+publisher:"University of Texas – Austin" +contributor:("Rochelle, Gary T")

University of Texas – Austin

1. -4185-8607. Pilot plant modeling of Advanced Flash Stripper with piperazine.

Degree: MSin Engineering, Chemical Engineering, 2018, University of Texas – Austin

URL: http://dx.doi.org/10.26153/tsw/1318

► Implementation of carbon capture using amine scrubbing is limited by the large energy penalty of CO₂ capture and compression. Alternative stripper designs can reduce lost… (more)

Subjects/Keywords: Carbon capture; Pilot plant; Piperazine; Advanced flash stripper

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APA (6^th Edition):

-4185-8607. (2018). Pilot plant modeling of Advanced Flash Stripper with piperazine. (Masters Thesis). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/1318

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Chicago Manual of Style (16^th Edition):

-4185-8607. “Pilot plant modeling of Advanced Flash Stripper with piperazine.” 2018. Masters Thesis, University of Texas – Austin. Accessed March 07, 2021. http://dx.doi.org/10.26153/tsw/1318.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

MLA Handbook (7^th Edition):

-4185-8607. “Pilot plant modeling of Advanced Flash Stripper with piperazine.” 2018. Web. 07 Mar 2021.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

-4185-8607. Pilot plant modeling of Advanced Flash Stripper with piperazine. [Internet] [Masters thesis]. University of Texas – Austin; 2018. [cited 2021 Mar 07]. Available from: http://dx.doi.org/10.26153/tsw/1318.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Council of Science Editors:

-4185-8607. Pilot plant modeling of Advanced Flash Stripper with piperazine. [Masters Thesis]. University of Texas – Austin; 2018. Available from: http://dx.doi.org/10.26153/tsw/1318

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

University of Texas – Austin

2. Frailie, Peter Thompson, II. Modeling of carbon dioxide absorption/stripping by aqueous methyldiethanolamine/piperazine.

Degree: PhD, Chemical Engineering, 2014, University of Texas – Austin

URL: http://hdl.handle.net/2152/25019

► Rigorous thermodynamic and kinetic models were developed in Aspen Plus® Rate SepTM for 8 m PZ, 5 m PZ, 7 m MDEA/2 m PZ, and… (more)

▼ Rigorous thermodynamic and kinetic models were developed in Aspen Plus® Rate SepTM for 8 m PZ, 5 m PZ, 7 m MDEA/2 m PZ, and 5 m MDEA/5 m PZ. Thermodynamic data was regressed using a sequential regression methodology, and incorporated data for all amine, amine/water, and amine/water/CO₂ systems. The sensitivity of CO₂ absorption rate was determined in a wetted wall column simulation in Aspen Plus®, and the results were used in Microsoft Excel to determine the optimum reaction rates, activation energies, and binary diffusivities. Density, viscosity, and binary diffusivity are calculated using user-supplied FORTRAN subroutines rather than built-in Aspen Plus® correlations. Three absorber configurations were tested: adiabatic, in-and-out intercooling, and pump-around intercooling. The two intercooled configurations demonstrated comparable improvement in capacity and packing area, with the greatest improvement in 8 m PZ occurring between lean loadings of 0.20 and 0.25 mol CO₂/mol alkalinity. The effects of absorber temperature and CO₂ removal were tested in the adiabatic and in-and-out intercooled configurations. For 7 m MDEA/2 m PZ at a lean loading of 0.13 mol CO₂/mol alkalinity reducing the absorber temperature from 40 °C to 20 °C increases capacity by 64% without an appreciable increase in packing area. Increasing CO₂ removal from 90% to 99% does not double the packing area due to favorable reaction rates at the lean end of the absorber. Two stripper configurations were tested: the simple stripper and the advanced flash stripper. For all amines, absorber configurations, and lean loadings the advanced flash stripper demonstrated the better energy performance, with the greatest benefit occurring at low lean loadings. An economic estimation method was developed that converts purchased equipment cost and equivalent work to $/MT CO₂. The method is based on economic factors proposed by DOE-NETL and IEAGHG. The total cost of CO₂ decreases as lean loading decreases for all amines and configurations. Increasing CO₂ removal from 90% to 99% results in a 1% increase in the total cost of CO₂ capture. Decreasing absorber temperature for 7 m MDEA/2 m PZ from 40 °C to 20 °C decreases total cost of CO₂ capture by up to 9.3%. Advisors/Committee Members: Rochelle, Gary T. (advisor).

Subjects/Keywords: Carbon dioxide; Amine scrubbing

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Frailie, Peter Thompson, I. (2014). Modeling of carbon dioxide absorption/stripping by aqueous methyldiethanolamine/piperazine. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/25019

Chicago Manual of Style (16^th Edition):

Frailie, Peter Thompson, II. “Modeling of carbon dioxide absorption/stripping by aqueous methyldiethanolamine/piperazine.” 2014. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/25019.

MLA Handbook (7^th Edition):

Frailie, Peter Thompson, II. “Modeling of carbon dioxide absorption/stripping by aqueous methyldiethanolamine/piperazine.” 2014. Web. 07 Mar 2021.

Vancouver:

Frailie, Peter Thompson I. Modeling of carbon dioxide absorption/stripping by aqueous methyldiethanolamine/piperazine. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2014. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/25019.

Council of Science Editors:

Frailie, Peter Thompson I. Modeling of carbon dioxide absorption/stripping by aqueous methyldiethanolamine/piperazine. [Doctoral Dissertation]. University of Texas – Austin; 2014. Available from: http://hdl.handle.net/2152/25019

University of Texas – Austin

3. Ashouripashaki, Mandana. Formation and decomposition of 1-nitrosopiperazine in the CO2 capture process.

Degree: MSin Engineering, Chemical Engineering, 2012, University of Texas – Austin

URL: http://hdl.handle.net/2152/19710

► Piperazine (PZ) is a cyclic diamine, which means it can absorb two moles of CO2 per mole of amine and potentially has a higher capacity… (more)

▼ Piperazine (PZ) is a cyclic diamine, which means it can absorb two moles of CO2 per mole of amine and potentially has a higher capacity for CO2 capture than monoethanolamine, the current solvent of choice for flue gas treatment. Nitrosamines are formed from the reaction between secondary or tertiary amines and nitrites or nitrogen oxides. Over 80% of nitrosamines are carcinogenic. The reaction of PZ and nitrite can form 1-nitrosopiperazine (also mononitrosopiperazine, MNPZ) and N-N,dinitrosopiperazine (DNPZ). Carcinogenicity of DNPZ is almost 20 times as that of MNPZ. There is also a possibility of nitrosamine formation of PZ in the CO2 capture process because of NOx in input flue gas, with the oxidative and thermal degradation products of PZ. Analytical methods were developed in order to perform kinetic studies of the reaction between a nitrite solution and PZ over a range of temperature from 20 to 150 °C at two different PZ concentrations, 8 and 2 mol/kg of solution, and three levels of CO2 loading, 0.3, 0.2, and 0.1 mole CO2/mole of alkalinity. At less than 75 °C, nitrite reacts with PZ and disappears during the reaction to an equilibrium concentration while at the higher temperature; the concentration of nitrite quickly decreases to a very low value. There is no evidence of DNPZ as a reaction product in all reaction conditions, but MNPZ is formed at the temperature greater than 75 °C. The MNPZ concentration approaches a maximum value consistent with the material balance and nitrite disappearance. By developing the time of reaction at the higher temperature a decomposition of MNPZ has been observed, by either the reverse of the formation reaction or decomposition to other compounds. By increasing the temperature, the maximum value of MNPZ concentration is achieved more quickly and the rate of MNPZ decomposition increases. Reactions follow the same trend at both PZ concentration and at the three different degrees of CO2 loading. A model has been established considering temperature, PZ concentration, and CO2 loading. The calculated activation energies of MNPZ production and decomposition were determined. MNPZ decomposition is more rapid than PZ degradation. Advisors/Committee Members: Rochelle, Gary T. (advisor).

Subjects/Keywords: Piperazine; Nitrosopiperazine; CO2 capture

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APA (6^th Edition):

Ashouripashaki, M. (2012). Formation and decomposition of 1-nitrosopiperazine in the CO2 capture process. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/19710

Chicago Manual of Style (16^th Edition):

Ashouripashaki, Mandana. “Formation and decomposition of 1-nitrosopiperazine in the CO2 capture process.” 2012. Masters Thesis, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/19710.

MLA Handbook (7^th Edition):

Ashouripashaki, Mandana. “Formation and decomposition of 1-nitrosopiperazine in the CO2 capture process.” 2012. Web. 07 Mar 2021.

Vancouver:

Ashouripashaki M. Formation and decomposition of 1-nitrosopiperazine in the CO2 capture process. [Internet] [Masters thesis]. University of Texas – Austin; 2012. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/19710.

Council of Science Editors:

Ashouripashaki M. Formation and decomposition of 1-nitrosopiperazine in the CO2 capture process. [Masters Thesis]. University of Texas – Austin; 2012. Available from: http://hdl.handle.net/2152/19710

University of Texas – Austin

4. Ding, Junyuan. Modeling the advanced flash stripper for CO2 capture using 5 m piperazine.

Degree: MSin Engineering, Chemical engineering, 2016, University of Texas – Austin

URL: http://hdl.handle.net/2152/45549

► Amine scrubbing is the most mature technology for post-combustion CO2 capture. Several studies have demonstrated that the advanced flash stripper (AFS) consumes less energy among… (more)

▼ Amine scrubbing is the most mature technology for post-combustion CO2 capture. Several studies have demonstrated that the advanced flash stripper (AFS) consumes less energy among stripper alternatives. This thesis seeks to demonstrate the AFS energy performance and cost over a wide range of CO2 loading. Solvent models based on experimental results have been created by previous researchers and are available for simulation and process modeling in Aspen Plus®. In collaboration with Membrane Technology and Research Inc., various hybrid amine/membrane configurations were studied to minimize the total CO2 capture cost. CO2 in the flue gas is enriched by membranes from 12% to 18 and 23% for coal-fired power plant, and from 6% to 12~18% for natural gas combined cycle power plant (NGCC). The CO2 loading covers the range of flue gas CO2 from coal-fired power plants and NGCC. For each configuration, the cold and warm rich bypasses are optimized to minimize the energy cost. The cost optimization is also demonstrated on 5 m PZ, 5 m MDEA/5 m PZ, and 2 m PZ/3 m HMPD. The most cost-effective solvent varies with the flue gas CO2. When applied to a coal-fired power plant, hybrid parallel amine/membrane designs with 99% and 95% CO2 removal cost less than hybrid series with 60% CO2 removal. The equivalent work of the parallel configuration with 99% CO2 removal using 5 m MDEA/5 m PZ (32.3 kJ/mol CO2) is less than using 5 m PZ (34.0 kJ/mol CO2). The equivalent work with 95% CO2 removal (Case 19) using 5 m MDEA/5 m PZ (32.5 kJ/mol CO2) is less than using 5 m PZ (33.3 kJ/mol CO2). The capital cost with 99% CO2 removal using 5 m MDEA/5 m PZ (70.5MM) is more than using 5 m PZ (67.5MM). The capital cost with 95% CO2 removal using 5 m MDEA/5 m PZ (73.5MM) is less than using 5 m PZ (79.5MM). The total annual cost with 95% CO2 removal using 2 m PZ/3 m HMPD (38.7/tonne CO2) is less than using 5 m PZ (41.5/tonne CO2). When applied to NGCC, the cost of amine scrubbing is reduced by increasing absorber inlet CO2 by membranes. However, this is offset by the membrane cost. As absorber inlet CO2 increases from 6% to 18%, the operating cost decreases from 18.8 to 15.4/tonne CO2, while total regeneration cost decreases from 35.6 to 33.1/tonne CO2. Advisors/Committee Members: Rochelle, Gary T. (advisor).

Subjects/Keywords: Stripper; CO2 capture; Amine scrubbing; Coal-fired; NGCC

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APA (6^th Edition):

Ding, J. (2016). Modeling the advanced flash stripper for CO2 capture using 5 m piperazine. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/45549

Chicago Manual of Style (16^th Edition):

Ding, Junyuan. “Modeling the advanced flash stripper for CO2 capture using 5 m piperazine.” 2016. Masters Thesis, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/45549.

MLA Handbook (7^th Edition):

Ding, Junyuan. “Modeling the advanced flash stripper for CO2 capture using 5 m piperazine.” 2016. Web. 07 Mar 2021.

Vancouver:

Ding J. Modeling the advanced flash stripper for CO2 capture using 5 m piperazine. [Internet] [Masters thesis]. University of Texas – Austin; 2016. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/45549.

Council of Science Editors:

Ding J. Modeling the advanced flash stripper for CO2 capture using 5 m piperazine. [Masters Thesis]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/45549

5. Du, Yang, active 21st century. Thermodynamics of aqueous piperazine/aminoethylpiperazine for CO₂ capture.

Degree: MSin Engineering, Chemical Engineering, 2014, University of Texas – Austin

URL: http://hdl.handle.net/2152/25831

► Aqueous piperazine (PZ) blended with N-(2-aminoethyl) piperazine (AEP) is an attractive solvent for CO₂ capture from coal-fired power plants. Blending PZ with AEP can remediate… (more)

Subjects/Keywords: Piperazine; N-(2-aminoethyl) piperazine; CO₂ capture; Thermodynamics; Modeling

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APA (6^th Edition):

Du, Yang, a. 2. c. (2014). Thermodynamics of aqueous piperazine/aminoethylpiperazine for CO₂ capture. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/25831

Chicago Manual of Style (16^th Edition):

Du, Yang, active 21st century. “Thermodynamics of aqueous piperazine/aminoethylpiperazine for CO₂ capture.” 2014. Masters Thesis, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/25831.

MLA Handbook (7^th Edition):

Du, Yang, active 21st century. “Thermodynamics of aqueous piperazine/aminoethylpiperazine for CO₂ capture.” 2014. Web. 07 Mar 2021.

Vancouver:

Du, Yang a2c. Thermodynamics of aqueous piperazine/aminoethylpiperazine for CO₂ capture. [Internet] [Masters thesis]. University of Texas – Austin; 2014. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/25831.

Council of Science Editors:

Du, Yang a2c. Thermodynamics of aqueous piperazine/aminoethylpiperazine for CO₂ capture. [Masters Thesis]. University of Texas – Austin; 2014. Available from: http://hdl.handle.net/2152/25831

6. Nguyen, Bich-Thu Ngoc. Amine volatility in CO₂ capture.

Degree: PhD, Chemical Engineering, 2013, University of Texas – Austin

URL: http://hdl.handle.net/2152/21988

► This work investigates the volatilities of amine solvents used in post-combustion CO₂ capture from coal-fired power plants. Amine volatility is one of the key criteria… (more)

▼ This work investigates the volatilities of amine solvents used in post-combustion CO₂ capture from coal-fired power plants. Amine volatility is one of the key criteria used in screening an amine solvent for CO₂ capture: (1) amine losses up the stack can react in the atmosphere to form ozone and other toxic compounds; (2) volatility losses can result in greater solvent make-up costs; (3) high losses will require the use of bigger water wash units, and more water, to capture fugitive amines prior to venting - these translate to higher capital and operating costs; (4) volatilities need to be measured and modeled in order to develop more accurate and robust thermodynamic models. In this work, volatility is measured using a hot gas FTIR which can determine amine, water, and CO₂ in the vapor headspace above a solution. The liquid solution is speciated by NMR (Nuclear Magnetic Resonance). There are two key contributions made by this research work: (1) it serves as one of the largest sources of experimental data available for amine-water volatility; (2) it provides amine volatility for loaded systems (where CO₂ is present) which is a unique measurement not previously reported in the literature. This work studied the volatility of 20 alkanolamines in water at 0.5 - 1.1 molal (m) in water (< 1.5 mol% amine) at zero loading (no CO₂) from 40 ° - 70 °C. An empirical group contribution model was developed to correlate H[subscript 'amine'] to molecular structures of both alkylamines and alkanolamines. The model incorporated additional functional groups to account for cyclic structures and to distinguish between different types of alkyl groups based on the attached neighboring groups. This model represented the experimental H[subscript 'amine'], which spanned five orders in magnitude, to well within an order of magnitude of the measured values. The second component of this research involves upgrading the AspenPlus® v.7.3 model of MDEA-PZ-CO₂-H₂O system primarily by improving MDEA thermodynamics for MDEA-H₂O, MDEA-CO₂-H₂O, and MDEA-PZ-CO₂-H₂O. A key modification was made to include the carbonate (CO₃²⁻) species into the model chemistry set which greatly improved the fit of CO₂ solubility for MDEA-CO₂-H₂O at ultra lean loading ([alpha]) for 0.001 < [alpha] < 0.01. With MDEA-PZ-H₂O, no MDEA-PZ cross interaction parameters were needed to match the blend volatility. Ultimately, both the blend volatility, at unloaded and loaded conditions, along with speciation were adequately represented by the upgraded model. The final component of this research involves screening the volatilities of novel amines at unloaded and nominal lean loading condition from 40 ° - 70 °C (absorber operating conditions). The volatility of tertiary and hindered amines, such as MDEA and AMP, respectively, is not a strong function of loading because these amines are unable to form stable carbamates. Conversely, the volatility of mono-amines and of diamines decreases by ~3 and 5-20 times, respectively, due to a much greater extent of carbamate-forming speciation. PZ or… Advisors/Committee Members: Rochelle, Gary T. (advisor).

Subjects/Keywords: CO2; MEA; MDEA; PZ; Henrys constant; Group contribution; Amine screening; Thermodynamic model

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APA (6^th Edition):

Nguyen, B. N. (2013). Amine volatility in CO₂ capture. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/21988

Chicago Manual of Style (16^th Edition):

Nguyen, Bich-Thu Ngoc. “Amine volatility in CO₂ capture.” 2013. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/21988.

MLA Handbook (7^th Edition):

Nguyen, Bich-Thu Ngoc. “Amine volatility in CO₂ capture.” 2013. Web. 07 Mar 2021.

Vancouver:

Nguyen BN. Amine volatility in CO₂ capture. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2013. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/21988.

Council of Science Editors:

Nguyen BN. Amine volatility in CO₂ capture. [Doctoral Dissertation]. University of Texas – Austin; 2013. Available from: http://hdl.handle.net/2152/21988

7. Xu, Qing, doctor of chemical engineering. Thermodynamics of CO₂ loaded aqueous amines.

Degree: PhD, Chemical Engineering, 2011, University of Texas – Austin

URL: http://hdl.handle.net/2152/ETD-UT-2011-12-4819

► Thermodynamics is important for the design of amine scrubbing CO₂ capture processes. CO₂ solubility and amine volatility in aqueous amines were measured at high temperature… (more)

▼ Thermodynamics is important for the design of amine scrubbing CO₂ capture processes. CO₂ solubility and amine volatility in aqueous amines were measured at high temperature and pressure. A rigorous thermodynamic model was developed for MEA-CO₂-H₂O in Aspen Plus®. CO₂ solubility at 80-190°C was obtained from total pressure measurements. Empirical models as a function of temperature and loading were developed for CO₂ solubility from 40 to 160°C in aqueous monoethanolamine (MEA), piperazine (PZ), 1-methylpiperazine (1MPZ), 2-methylpiperazine (2MPZ), PZ/2MPZ, diglycolamine® (DGA®), PZ/1MPZ/1,4-dimethylpiperazine (1,4-DMPZ), and PZ/methyldiethanolamine (MDEA). The high temperature CO₂ solubility data for MEA is comparable to literature and compatible with previous low temperature data. For MEA and PZ, amine concentration does not have obvious effects on the CO₂ solubility. The heat of CO₂ absorption derived from these models varies from 66 kJ/mol for 4 m (molal) PZ/4 m 2MPZ and to 72, 72, and 73 kJ/mol for MEA, 7 m MDEA/2 m PZ, and DGA. The heat of absorption estimated from the total pressure data does not vary significantly with temperature. At 0-0.5 loading ([alpha]), 313-413 K, 3.5-11 m MEA (mol fraction x is 0.059-0.165), the empirical model of MEA volatility is ln(PMEA/xMEA) = 30.0-8153/T-2594[alpha]²/T. In 7 m MEA with 0.2 and 0.5 loading, PMEA is 920 and 230 Pa at 120°C. At 0.3-0.5 loading, the enthalpy of MEA vaporization, -[Delta]Hvap,MEA, is about 70-73 kJ/mol MEA. At 0.25-0.4 loading, 313-423 K, 4.7-11.3 m PZ (x is 0.078-0.169), the empirical model of PZ volatility is ln(PPZ/xPZ) = -123+21.6lnT+20.2[alpha]-18174[alpha]²/T. In 8 m PZ with 0.3 and 0.4 loading, PPZ is 400 and 120 Pa at 120°C, and 2620 and 980 Pa at 150°C. At 0.25-0.4 loading, -[Delta]Hvap,PZ is about 85-100 kJ/mol PZ at 150°C and 66-80 kJ/mol PZ at 40°C. [Delta]Hvap,PZ has a larger dependence on CO₂ loading than [Delta]Hvap,MEA in rich solution because of the more complex speciation/reactions in PZ at rich loading. Specific heat capacity of 8 m PZ is 3.43-3.81 J/(g•K) at 70-150°C. Two new thermodynamic models of MEA-CO₂-H₂O were developed in Aspen Plus® starting with the Hilliard (2008) MEA model. One (Model B) includes a new species MEACOOH and it gets a better prediction than the other (Model A) for CO₂ solubility, MEA volatility, heat of absorption, and other thermodynamic results. The Model B prediction matches the experimental pKa of MEACOOH, and the measured concentration of MEACOO-/MEACOOH by NMR. In the prediction the concentration of MEACOOH is 0.1-3% in 7 m MEA at high temperature or high loading, where the heat of formation of MEACOOH has effects on PCO₂ and CO₂ heat of absorption. Model B solved the problems of Model A by adding MEACOOH and matched the experimental data of pKa and speciation, therefore MEACOOH may be considered an important species at high temperature or high loading. Although mostly developed from 7 m MEA data, Model B also gives a good profile for 11 m (40 wt%) MEA. Advisors/Committee Members: Rochelle, Gary T. (advisor).

Subjects/Keywords: Thermodynamics; CO₂ capture; Aqueous amine; CO₂ solubility; Amine volatility; Aspen plus model; Heat of absorption

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APA (6^th Edition):

Xu, Qing, d. o. c. e. (2011). Thermodynamics of CO₂ loaded aqueous amines. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2011-12-4819

Chicago Manual of Style (16^th Edition):

Xu, Qing, doctor of chemical engineering. “Thermodynamics of CO₂ loaded aqueous amines.” 2011. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/ETD-UT-2011-12-4819.

MLA Handbook (7^th Edition):

Xu, Qing, doctor of chemical engineering. “Thermodynamics of CO₂ loaded aqueous amines.” 2011. Web. 07 Mar 2021.

Vancouver:

Xu, Qing doce. Thermodynamics of CO₂ loaded aqueous amines. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2011. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/ETD-UT-2011-12-4819.

Council of Science Editors:

Xu, Qing doce. Thermodynamics of CO₂ loaded aqueous amines. [Doctoral Dissertation]. University of Texas – Austin; 2011. Available from: http://hdl.handle.net/2152/ETD-UT-2011-12-4819

8. Madan, Tarun. Modeling of stripper configurations for CO₂ capture using aqueous piperazine.

Degree: MSin Engineering, Chemical Engineering, 2013, University of Texas – Austin

URL: http://hdl.handle.net/2152/21486

► This thesis seeks to improve the economic viability of carbon capture process by reducing the energy requirement of amine scrubbing technology. High steam requirement for… (more)

▼ This thesis seeks to improve the economic viability of carbon capture process by reducing the energy requirement of amine scrubbing technology. High steam requirement for solvent regeneration in this technology can be reduced by improvements in the regeneration process. Solvent models based on experimental results have been created by previous researchers and are available for simulation and process modeling in Aspen Plus®. Standard process modeling specifications are developed and multiple regeneration processes are compared for piperazine (a cyclic diamine) in Chapter 2. The configurations were optimized to identify optimal operating conditions for energy performance. These processes utilize methods of better heat recovery and effective separation and show 2 to 8% improvement in energy requirement as compared to conventional absorber-stripper configuration. The best configuration is the interheated stripper which requires equivalent work of 29.9 kJ/mol CO₂ compared to 32.6 kJ/mol CO₂ for the simple stripper. The Fawkes and Independence solvent models were used for modeling and simulation. A new regeneration configuration called the advanced flash stripper (patent pending) was developed and simulated using the Independence model. Multiple complex levels of the process were simulated and results show more than 10% improvement in energy performance. Multiple cases of operating conditions and process specifications were simulated and the best case requires equivalent work of 29 kJ/mol CO₂. This work also includes modeling and simulation of pilot plant campaigns carried out for demonstration of a piperazine with a 2-stage flash on at 1 tpd CO₂. Reconciliation of data was done in Aspen Plus for solvent model validation. The solvent model predicted results consistent with the measured values. A systematic error of approximately +5% was found in the rich CO₂, that can be attributed to laboratory measurement errors, instrument measurement errors, and standard deviation in solvent model data. Stripper Modeling for CO₂ capture from natural gas combustion was done under a project by TOTAL through the Process Science and Technology Center. Two configurations were simulated for each of three flue gas conditions (corresponding to 3%, 6% and 9% CO₂). Best cases for the three conditions of flue gas require 34.9, 33.1 and 31.6 kJ/mol CO₂. Advisors/Committee Members: Rochelle, Gary T. (advisor).

Subjects/Keywords: Piperazine; Carbon capture; Amine scrubbing; Stripper configuration

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APA (6^th Edition):

Madan, T. (2013). Modeling of stripper configurations for CO₂ capture using aqueous piperazine. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/21486

Chicago Manual of Style (16^th Edition):

Madan, Tarun. “Modeling of stripper configurations for CO₂ capture using aqueous piperazine.” 2013. Masters Thesis, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/21486.

MLA Handbook (7^th Edition):

Madan, Tarun. “Modeling of stripper configurations for CO₂ capture using aqueous piperazine.” 2013. Web. 07 Mar 2021.

Vancouver:

Madan T. Modeling of stripper configurations for CO₂ capture using aqueous piperazine. [Internet] [Masters thesis]. University of Texas – Austin; 2013. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/21486.

Council of Science Editors:

Madan T. Modeling of stripper configurations for CO₂ capture using aqueous piperazine. [Masters Thesis]. University of Texas – Austin; 2013. Available from: http://hdl.handle.net/2152/21486

9. Sexton, Andrew James, 1981-. Amine oxidation in CO₂ capture processes.

Degree: PhD, Chemical Engineering, 2008, University of Texas – Austin

URL: http://hdl.handle.net/2152/18121

► Aqueous amine solutions were batch loaded into 500 mL glass jacketed reactors and subjected to oxidative degradation at both low and high gas rates. Solutions… (more)

▼ Aqueous amine solutions were batch loaded into 500 mL glass jacketed reactors and subjected to oxidative degradation at both low and high gas rates. Solutions at low gas were degraded with 100 mL/min of 98%O2/2%CO2 with mass transfer achieved by vortexing. Samples were drawn from the reactor during the course of the experiment and analyzed for degradation using ion chromatography and HPLC with evaporative light scattering detecion. In a parallel apparatus 7.5 L/min of 15%O2/2%CO2 was sparged through 350 mL of solution; additional mass transfer was achieved by vortexing. A Fourier Transform Infrared Analyzer collected continuous gas-phase data on amine volatility and volatile degradation products. Hydroxyethyl-formamide (HEF), hydroxyethylimidazole (HEI) and formate are the major carbon containing monoethanolamine (MEA) oxidation products; HEF, HEI and ammonia are the major nitrogen containing products. In terms of catalyst oxidation potential, Cu > Cr/Ni (combined) > Fe > V. The oxygen stoichiometry (ν) ranges from 1.5 mol MEA degraded/mol O2 consumed for Cu and Fe catalyzed systems to 1.0 for V catalyzed systems. Estimation of rates from an industrial absorber show degradation costs to range from $1.17 / metric ton (MT) CO2 captured for a system controlled by the solubility of O2 to $2.22 / MT CO2 for a mass transfer controlled system. Inhibitors A and B (reaction mechanism inhibitors) and EDTA (a chelating agent) were established as effective MEA oxidation inhibitors. EDTA and Inhibitor A were successful inhibitors at 100 mM, while 7.5 mM Inhibitor B successfully inhibited degradation. Sodium sulfite and reaction intermediates formaldehyde and formate (expected oxygen scavengers) were unsuccessful at inhibiting MEA oxidation. Cu catalyzes concentrated PZ oxidation, while Fe has no effect on PZ oxidation even at high catalyst concentration. MEA/PZ blends were more susceptible to oxidation than any other amine system investigated. It is believed that free radicals formed in the MEA oxidation process serve to accelerate the degradation of the PZ structure. All MEA analogs (glycine, ethylenediamine and ethylene glycol) and secondary/hindered amines (diethanolamine, diglycolamine and 2-amino-2-methyl-1-propanol) were resistant to oxidation in the presence of Fe or Cu, except for diethanolamine. Advisors/Committee Members: Rochelle, Gary T. (advisor).

Subjects/Keywords: Amines; Mass transfer

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APA (6^th Edition):

Sexton, Andrew James, 1. (2008). Amine oxidation in CO₂ capture processes. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/18121

Chicago Manual of Style (16^th Edition):

Sexton, Andrew James, 1981-. “Amine oxidation in CO₂ capture processes.” 2008. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/18121.

MLA Handbook (7^th Edition):

Sexton, Andrew James, 1981-. “Amine oxidation in CO₂ capture processes.” 2008. Web. 07 Mar 2021.

Vancouver:

Sexton, Andrew James 1. Amine oxidation in CO₂ capture processes. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2008. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/18121.

Council of Science Editors:

Sexton, Andrew James 1. Amine oxidation in CO₂ capture processes. [Doctoral Dissertation]. University of Texas – Austin; 2008. Available from: http://hdl.handle.net/2152/18121

University of Texas – Austin

10. Stowe, Haley Maren. Theoretical studies of aqueous amine solvents for carbon dioxide capture.

Degree: PhD, Materials Science and Engineering, 2020, University of Texas – Austin

URL: http://dx.doi.org/10.26153/tsw/10191

► Aqueous amine-based chemical scrubbing has been considered the most promising near-term solution for CO₂ capture from flue gas, yet the underlying reaction mechanisms are still… (more)

▼ Aqueous amine-based chemical scrubbing has been considered the most promising near-term solution for CO₂ capture from flue gas, yet the underlying reaction mechanisms are still not fully understood. Moreover, its widespread implementation is hindered by the high cost associated with the parasitic energy consumption during solvent regeneration, along with degradation and corrosion problems. First-principles-based atomistic modeling can play a significant role in elucidating the complex physicochemical phenomena underlying CO₂ reaction-diffusion behavior in aqueous amine-based solvent, especially when direct experimental characterization at the atomic level may be difficult. An improved fundamental understanding of these reaction mechanisms and intermolecular interactions can be used to provide explanations for experimental observations and fundamental data, and improve kinetic and thermodynamic models for process optimization. Here, our recent theoretical works on the molecular mechanisms underlying CO₂ capture and solvent regeneration in aqueous amines are presented. Through systematic comparative analyses of primary, tertiary, and sterically hindered amines, and diamines, we provide significant insights into how the mechanisms and rates of competing CO₂ absorption routes can be influenced by the solvent structure, the relative strengths of intra- and intermolecular hydrogen bond interactions, and steric constraints. We also use a theoretical approach to examine the mechanisms occurring during thermal degradation, as well as the process underlying leaching of metal ions into solution due to corrosion and subsequent oxidative degradation, which remain unclear. These studies further demonstrate the importance of a detailed atomic-level description of the solution structure and dynamics to describe the reactions and in predicting the thermodynamic and kinetic properties in CO₂-loaded aqueous amines. Moreover, an accurate description of solvent composition near the gas interface and near the iron surface is critical in predicting the CO₂ capture and corrosion processes, respectively. This dissertation highlights the increasingly important role of first-principles-based computer simulations in the detailed mechanistic study of CO₂ capture by amine-based solvents, including solvent degradation and corrosion processes. The improved understanding gained from computational studies combined with experiment validations will greatly aid in the design and development of new solvents and inhibitors in efforts to improve the efficiency of commercial-scale applications Advisors/Committee Members: Hwang, Gyeong S. (advisor), Henkelman, Graeme (committee member), Johnston, Keith P (committee member), Ren, Pengyu (committee member), Rochelle, Gary T (committee member).

Subjects/Keywords: Carbon capture; CO₂; Molecular dynamics; Aqueous amine

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APA (6^th Edition):

Stowe, H. M. (2020). Theoretical studies of aqueous amine solvents for carbon dioxide capture. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/10191

Chicago Manual of Style (16^th Edition):

Stowe, Haley Maren. “Theoretical studies of aqueous amine solvents for carbon dioxide capture.” 2020. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://dx.doi.org/10.26153/tsw/10191.

MLA Handbook (7^th Edition):

Stowe, Haley Maren. “Theoretical studies of aqueous amine solvents for carbon dioxide capture.” 2020. Web. 07 Mar 2021.

Vancouver:

Stowe HM. Theoretical studies of aqueous amine solvents for carbon dioxide capture. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2020. [cited 2021 Mar 07]. Available from: http://dx.doi.org/10.26153/tsw/10191.

Council of Science Editors:

Stowe HM. Theoretical studies of aqueous amine solvents for carbon dioxide capture. [Doctoral Dissertation]. University of Texas – Austin; 2020. Available from: http://dx.doi.org/10.26153/tsw/10191

University of Texas – Austin

11. James, Corey Matthew, 1976-. Reducing the cost of operational water on military bases through modeling, optimization, and control.

Degree: PhD, Chemical Engineering, 2017, University of Texas – Austin

URL: http://hdl.handle.net/2152/62970

► Military municipal water systems provide safe and clean water to the surrounding community while also supporting the intense and often unpredictable training schedules of the… (more)

▼ Military municipal water systems provide safe and clean water to the surrounding community while also supporting the intense and often unpredictable training schedules of the tenant units. Much like their civilian counterparts, military water systems are also consumers of great amounts of energy and capital. As a part of the Army Net Zero program in 2011, an annual water inventory conducted on eight U.S. Army installations concluded that consumption was 5.5 billion gallons. Using the Environmental Protection Agency’s average national estimate of 1,500 kWh of energy consumed for every 1,000 gallons of treated water, it is readily apparent that the department of defense is a heavy consumer of both water and energy. Because the scale of the military’s usage is so vast, so too is their waste. Waste in water systems is common and commonly neglected, as many were initially constructed decades ago and the commodity that they transport is relatively inexpensive. However, recent droughts affecting regions of the United States highlighted the need to conserve and avoid waste, regardless of the commodity price. The efficiency of water systems is highly dependent upon developing accurate models and using those models to accurately deal with disturbances such as demand and chlorine concentration. This work extends water distribution system modeling, optimization, and control to a military setting where constraints are tighter for resiliency purposes, demands are often unpredictable, and saving money and water improves defense capabilities. First, a discretized nonlinear, equation based model of a known system at an existing U.S. Army installation that accurately predicts system behavior under typical demand considerations. The model is calibrated for accuracy using actual system data from a military installation and employed in a nonlinear optimization program to study reduction of costs, minimizing waste, and improvements in energy efficiency. Demand profiles were constructed from residential data and scaled to better represent demand on military bases. With very little adjustment, this model can be used to optimize similar systems in the military inventory. Water and energy savings exceed 10% in the optimized system, which predicts the Army could save greater than $1.5 million per year in the continental United States if rigorous optimization was conducted on storage and pumping at every base. It is shown that a reduced order empirical model is a viable alternative to the computationally expensive equation based approach. The empirical model is used to implement model predictive control, providing the system protection against large and unpredictable disturbances. This method adds an additional manipulated variable, chlorine injection, to ensure efficient constraint compliance. Experimental results show this method further supports the aforementioned savings in the optimized system alone, while efficiently handling disturbances. This research closes previous gaps in research, particularly on military installations. First,… Advisors/Committee Members: Edgar, Thomas F. (advisor), Webber, Michael E., 1971- (advisor), Rochelle, Gary T (committee member), Baldea, Michael (committee member), Werth, Charles J (committee member).

Subjects/Keywords: Control; Optimization; Water; Energy; Military

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APA (6^th Edition):

James, Corey Matthew, 1. (2017). Reducing the cost of operational water on military bases through modeling, optimization, and control. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/62970

Chicago Manual of Style (16^th Edition):

James, Corey Matthew, 1976-. “Reducing the cost of operational water on military bases through modeling, optimization, and control.” 2017. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/62970.

MLA Handbook (7^th Edition):

James, Corey Matthew, 1976-. “Reducing the cost of operational water on military bases through modeling, optimization, and control.” 2017. Web. 07 Mar 2021.

Vancouver:

James, Corey Matthew 1. Reducing the cost of operational water on military bases through modeling, optimization, and control. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2017. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/62970.

Council of Science Editors:

James, Corey Matthew 1. Reducing the cost of operational water on military bases through modeling, optimization, and control. [Doctoral Dissertation]. University of Texas – Austin; 2017. Available from: http://hdl.handle.net/2152/62970

University of Texas – Austin

12. Perez, Krystian Xavier. Analysis, modeling and optimization of residential energy use from smart meter data.

Degree: PhD, Chemical engineering, 2016, University of Texas – Austin

URL: http://hdl.handle.net/2152/46454

► Approximately 38% of electricity consumption within the United States can be attributed to residential buildings, a vast share of which is in heating, ventilation and… (more)

▼ Approximately 38% of electricity consumption within the United States can be attributed to residential buildings, a vast share of which is in heating, ventilation and cooling. The load placed on the grid by residential consumers is highly variable and strongly influenced by weather and human activity patterns. Meeting fluctuations in demand is challenging and expensive for electricity producers and grid operators. Reducing variability in residential energy use can contribute significantly to increasing the uniformity of energy demand on the grid and diminish reliance on inefficient, polluting “peaking” plants that are used to meet extremely high demands. Achieving this goal requires tight coordination between energy consumption and generation, as well as the means to store energy generated in periods of low demand for use during the time intervals when consumer demand peaks. There is a common perception that a single home has a minor impact on the entire grid. However, owing to the fact that consumption patterns of homes are similar, while a single home does not have a large impact on the grid, entire neighborhoods do. Motivated by the above, this work explores the interaction between residential energy consumption and the electric grid. An analysis, modeling and optimization framework on smart meter data is developed to anticipate and modulate energy usage of ensembles of residential homes in order to reduce peak power demand. Much of the data used in this work come from Pecan Street, Inc., a smart grid demonstration project in Austin, TX. First, a nonintrusive load monitoring algorithm is developed to isolate air-conditioning (A/C) energy use from whole-house energy consumption data. Subsequently, a simplified reduced-order model is derived from smart meter data and thermostat set-point data to predict A/C energy use. The models of an ensemble of homes are placed within a centralized model predictive control scheme to minimize peak community A/C energy use. Reductions in peak energy use are achieved by shifting the thermostat set-points of individual homes. The approach is further expanded by simultaneously scheduling the operation of time-shiftable appliances to further reduce the community peak load. This integrated operation reduces peak loads by an average of 25.5%. This work also considers the impact of control and optimization techniques on designing a micro-grid that operates near autonomously from the electric power grid. Lastly, this work presents a tool to compare energy demand patterns of houses from smart meter data and indicates that high-energy houses would benefit from energy audits to improve energy efficiency. Advisors/Committee Members: Edgar, Thomas F. (advisor), Baldea, Michael (advisor), Novoselac, Atila (committee member), Webber, Michael E (committee member), Rochelle, Gary T (committee member).

Subjects/Keywords: Residential energy; Home energy management

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APA (6^th Edition):

Perez, K. X. (2016). Analysis, modeling and optimization of residential energy use from smart meter data. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/46454

Chicago Manual of Style (16^th Edition):

Perez, Krystian Xavier. “Analysis, modeling and optimization of residential energy use from smart meter data.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/46454.

MLA Handbook (7^th Edition):

Perez, Krystian Xavier. “Analysis, modeling and optimization of residential energy use from smart meter data.” 2016. Web. 07 Mar 2021.

Vancouver:

Perez KX. Analysis, modeling and optimization of residential energy use from smart meter data. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/46454.

Council of Science Editors:

Perez KX. Analysis, modeling and optimization of residential energy use from smart meter data. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/46454

University of Texas – Austin

13. -0020-5212. Dynamic modeling of post-combustion amine scrubbing for process control strategy development.

Degree: PhD, Chemical engineering, 2016, University of Texas – Austin

URL: http://hdl.handle.net/2152/39612

► Intensified process designs with advanced solvents have been proposed to decrease both capital and operating costs of post-combustion carbon capture with amine scrubbing. These advanced… (more)

▼ Intensified process designs with advanced solvents have been proposed to decrease both capital and operating costs of post-combustion carbon capture with amine scrubbing. These advanced flowsheets create process control challenges because process variables are designed to operate near constraints and the degrees of freedom are increased due to heat recovery. Additionally, amine scrubbing is tightly integrated with the upstream power plant and downstream enhanced oil recovery (EOR) facility. This work simulated an amine scrubbing plant that uses an intercooled absorber and advanced flash stripper configuration with aqueous piperazine to capture CO2 from a 550 MWe coal-fired power plant. The objective of this research was to develop a process control strategy that resulted in favorable closed-loop dynamics and near-optimal conditions in response to disturbances and off-design operation. Two models were created for dynamic simulation of the amine scrubbing system: a medium-order model of an intercooled absorber column and a low-order model of the entire plant. The purpose of the medium-order model was to accurately predict the absorber temperature profile in order to identify a column temperature that can be controlled by manipulating the solvent circulation rate to maintain a constant liquid to gas ratio. The low-order model, which was shown to sufficiently represent dynamic process behavior through validation with pilot plant data, was used to develop a plantwide control strategy. A regulatory control layer was implemented and tested with bounding cases that represent either electricity generation requirements, CO2 emission regulations, or EOR constraints dominating the control strategy. Satisfying the operational and economic objectives of one system component was found to result in unfavorable dynamic performance for the remainder of the system. Self-optimizing control variables were identified for the energy recovery flowrates of the advanced flash stripper that maintained good energy performance in off-design conditions. Regulatory control alone could not satisfactorily achieve the set point for CO2 removal rate from the flue gas. A supervisory model predictive controller was developed that manipulates the set point for the stripper pressure controller in order to control removal. The straightforward single-input, single-output constrained linear model predictive controller exhibited a significant improvement compared to PI control alone. Advisors/Committee Members: Rochelle, Gary T. (advisor), Edgar, Thomas F. (advisor), Baldea, Michael (committee member), Akella, Maruthi R (committee member), Chen, Eric (committee member).

Subjects/Keywords: Amine scrubbing; Dynamic modeling; Process control; Carbon capture

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APA (6^th Edition):

-0020-5212. (2016). Dynamic modeling of post-combustion amine scrubbing for process control strategy development. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/39612

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Chicago Manual of Style (16^th Edition):

-0020-5212. “Dynamic modeling of post-combustion amine scrubbing for process control strategy development.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/39612.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

MLA Handbook (7^th Edition):

-0020-5212. “Dynamic modeling of post-combustion amine scrubbing for process control strategy development.” 2016. Web. 07 Mar 2021.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

-0020-5212. Dynamic modeling of post-combustion amine scrubbing for process control strategy development. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/39612.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Council of Science Editors:

-0020-5212. Dynamic modeling of post-combustion amine scrubbing for process control strategy development. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/39612

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

University of Texas – Austin

14. Huang, Ph. D., Ling. The effects of drought on predicted air quality in Texas.

Degree: PhD, Chemical engineering, 2015, University of Texas – Austin

URL: http://hdl.handle.net/2152/32179

► Drought is a natural disaster that has profound and complex social, economic, and environmental impacts. As drought is predicted to occur more frequently within Texas… (more)

▼ Drought is a natural disaster that has profound and complex social, economic, and environmental impacts. As drought is predicted to occur more frequently within Texas with changes in future climate, it is critical to understand its impacts on regional air quality as the State endeavors to achieve and maintain attainment with National Ambient Air Quality Standards for ozone and fine particulate matter. Drought-induced changes in various natural systems, including emissions of biogenic hydrocarbons from vegetation and the physical removal of pollutants by vegetation via dry deposition, have the potential to effect air quality. This work characterizes land cover for eastern Texas climate regions during years with severe to exceptional drought conditions as well as years with average to above average precipitation patterns. Variability in meteorological conditions, biogenic emissions, and dry deposition rates is explored with widely applied global and regional models that have been configured specifically for multi-year analysis of eastern Texas conditions. The Comprehensive Air Quality Model with Extensions (CAMx), which has been used for air quality planning and management efforts in Texas, is used to quantify the relative contributions of various physical and chemical processes to ground-level ozone formation and changes in ground-level ozone concentrations during representative drought and wet periods. The analyses indicate that drought influences air quality in complex ways. This work suggests that the two largest drought driven changes to the physical and chemical processes that influence air quality are increased biogenic emissions due to elevated temperatures and decreased air pollutant removal through dry deposition due to changes in leaf-level processes. Both of these changes degrade air quality and their combined effect can be as large as an increase of approximately 5 ppb in ground level, 8-hour averaged ozone concentrations in parts of eastern Texas. The effects of soil moisture on biogenic emissions estimates can be as significant as temperature, but current land surface model configurations and the adequacy of the Model of Emissions of Gases and Aerosols Nature (MEGAN) algorithm to fully represent short and long-term responses to soil moisture remain highly uncertain. The characterization of soil moisture through ground and satellite-based measurement programs and validation of global and regional-scale land cover distributions should continue to be high priorities to support air quality planning in Texas. Advisors/Committee Members: Allen, David T. (advisor), McDonald-Buller, Elena (advisor), Hildebrandt Ruiz, Lea (committee member), Fu, Rong (committee member), Rochelle, Gary T (committee member).

Subjects/Keywords: Drought; Ground-level ozone; Biogenic emissions; Dry deposition

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Huang, Ph. D., L. (2015). The effects of drought on predicted air quality in Texas. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/32179

Chicago Manual of Style (16^th Edition):

Huang, Ph. D., Ling. “The effects of drought on predicted air quality in Texas.” 2015. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/32179.

MLA Handbook (7^th Edition):

Huang, Ph. D., Ling. “The effects of drought on predicted air quality in Texas.” 2015. Web. 07 Mar 2021.

Vancouver:

Huang, Ph. D. L. The effects of drought on predicted air quality in Texas. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2015. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/32179.

Council of Science Editors:

Huang, Ph. D. L. The effects of drought on predicted air quality in Texas. [Doctoral Dissertation]. University of Texas – Austin; 2015. Available from: http://hdl.handle.net/2152/32179

University of Texas – Austin

15. -2330-9786. Oxidation of piperazine in post-combustion carbon capture.

Degree: PhD, Chemical Engineering, 2018, University of Texas – Austin

URL: http://hdl.handle.net/2152/68015

► Solvent oxidation in amine scrubbing systems for post-combustion CO₂ capture is a significant issue. Piperazine (PZ) is a promising solvent due to its relative stability… (more)

▼ Solvent oxidation in amine scrubbing systems for post-combustion CO₂ capture is a significant issue. Piperazine (PZ) is a promising solvent due to its relative stability and performance. PZ oxidation rates and products were thoroughly characterized in the High Temperature Oxidation Reactor (HTOR) bench-scale cyclic degradation apparatus and compared to observed PZ oxidation from campaigns at the UT Austin SRP, CSIRO Tarong, and "Pilot Plant 2" (PP2) pilot-scale facilities. The HTOR simulated solvent conditions cycling between a 40-55 °C absorber and a 120-150 °C stripper. In both the bench and pilot-scale the intermediary degradation products piperazinol, piperazinone, and ethylenediamine were initially the most significant degradation products before reaching steady-state concentrations, with ammonia and formate the most significant final products produced from the decomposition of the intermediates. PZ oxidation increased as the solvent degraded due to the cycling of dissolved iron, aldehydes, and hydroperoxide contaminants, which could be oxidized in the absorber and subsequently oxidize PZ at high temperature. An N₂ sparger was used to selectively remove dissolved oxygen (DO) in the HTOR before heating while still allowing for oxidation due to contaminant cycling. Ammonia was correlated to dissolved iron at 0.72 mmol NH₃/kg PZ/hr/(mmol/kg Fe) [superscript 0.5]. An additional 0.4 mmol NH₃/kg/hr was produced due to direct reaction of PZ with DO regardless of the level of contamination. Dissolved iron was solubility-limited in both the HTOR and pilot plants, but increased as the solvent degraded, resulting in the autocatalytic effect of PZ oxidation. HTOR data was used to model oxidation and solvent management costs for a full-scale amine scrubber. The model matched observed oxidation at SRP and Tarong. Maintaining 0.1 to 0.5 wt % contaminant accumulation optimized amine make-up, solvent reclaiming, and increased energy costs due to changes in solvent viscosity, at a minimum of $2.6/MT CO₂ for PZ treating coal flue gas with a thermal reclaimer to remove contaminants. Feed rate and amine recovery in the reclaimer were the most impactful design variables, followed by operating temperature and hold-up in the stripper, prescrubbing of flue gas contaminants SO₂ and NO₂, and least significantly N₂ sparging to remove DO. Advisors/Committee Members: Rochelle, Gary T. (advisor), Ekerdt, John G (committee member), Willson, Grant (committee member), Chen, Eric (committee member), Sexton, Andrew J (committee member).

Subjects/Keywords: Carbon capture and sequestration; Amine scrubbing; Piperazine; Amine oxidation

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APA (6^th Edition):

-2330-9786. (2018). Oxidation of piperazine in post-combustion carbon capture. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/68015

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Chicago Manual of Style (16^th Edition):

-2330-9786. “Oxidation of piperazine in post-combustion carbon capture.” 2018. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/68015.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

MLA Handbook (7^th Edition):

-2330-9786. “Oxidation of piperazine in post-combustion carbon capture.” 2018. Web. 07 Mar 2021.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

-2330-9786. Oxidation of piperazine in post-combustion carbon capture. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2018. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/68015.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Council of Science Editors:

-2330-9786. Oxidation of piperazine in post-combustion carbon capture. [Doctoral Dissertation]. University of Texas – Austin; 2018. Available from: http://hdl.handle.net/2152/68015

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

University of Texas – Austin

16. -8257-6190. Corrosion of stainless and carbon steel in aqueous amine for CO₂ capture.

Degree: PhD, Chemical Engineering, 2019, University of Texas – Austin

URL: http://dx.doi.org/10.26153/tsw/2683

► Post-combustion carbon capture and storage with amine absorbents is a key technology needed to provide low-cost decarbonized electricity. Improving understanding of corrosion by amines may… (more)

▼ Post-combustion carbon capture and storage with amine absorbents is a key technology needed to provide low-cost decarbonized electricity. Improving understanding of corrosion by amines may reveal a solvent system compatible with carbon steel, which would reduce plant capital costs. Corrosion of stainless and carbon steel in aqueous monoethanolamine (MEA) and piperazine (PZ) has been measured. High temperature amine corrosion was measured in a bench-scale pressure vessel and iron solubility in amines was screened in stirred reactors. Corrosion was measured at two PZ pilot plants and one MEA pilot plant, using coupons and electrical resistance probes. Corrosion products were characterized by SEM and powder X-ray diffraction. Carbon steel (C1010) often performs well in 5 molal PZ up to 150 °C due to the formation of a passivating FeCO₃ layer. This layer is promoted at high temperature, high CO₂ loading, low solution velocity, and in amines with low Fe²⁺ solubility. FeCO₃ formation is favorable at high temperature because Fe²⁺ solubility decreases and the kinetics of FeCO₃ formation are faster. This also means that FeCO₃ is not observed at low temperature. Despite this, carbon steel performs well at low temperature due to slower kinetics of metal oxidation. Depassivation and high corrosion of stainless steel (316L) can occur in amine solutions at high temperature (150 °C) when conditions are relatively anoxic and reducing. Performance of stainless at high temperature in PZ suggests that it can be pushed into and out of the passive state by small process changes, such as different flue gas O₂ concentrations. However, stainless performs well in both MEA and PZ in pilot plants at ≈120 °C. Fe³⁺ corrosion products are generated in the absorber, then reduced to Fe²⁺ in the high temperature, anoxic conditions of the stripper. In this way, carried-over Fe³⁺ is responsible for oxidation of amine and corrosion at high temperature. Certain highly corrosive amines also have high Fe²⁺ solubility. Ethylamines like MEA are likely the correct chain length to form stable complexes with Fe²⁺ in solution. Stable Fe²⁺-amine complexes cause high Fe²⁺ solubility, which prevents FeCO₃ formation and leads to high corrosion. Advisors/Committee Members: Rochelle, Gary T. (advisor), Hwang, Gyeong S (committee member), Keitz, Benjamin K (committee member), Wheat, Harovel G (committee member).

Subjects/Keywords: Corrosion; CO₂ capture; Amine scrubbing; Piperazine; Monoethanolamine

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APA (6^th Edition):

-8257-6190. (2019). Corrosion of stainless and carbon steel in aqueous amine for CO₂ capture. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/2683

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Chicago Manual of Style (16^th Edition):

-8257-6190. “Corrosion of stainless and carbon steel in aqueous amine for CO₂ capture.” 2019. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://dx.doi.org/10.26153/tsw/2683.

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Author name may be incomplete

MLA Handbook (7^th Edition):

-8257-6190. “Corrosion of stainless and carbon steel in aqueous amine for CO₂ capture.” 2019. Web. 07 Mar 2021.

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Author name may be incomplete

Vancouver:

-8257-6190. Corrosion of stainless and carbon steel in aqueous amine for CO₂ capture. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2019. [cited 2021 Mar 07]. Available from: http://dx.doi.org/10.26153/tsw/2683.

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Author name may be incomplete

Council of Science Editors:

-8257-6190. Corrosion of stainless and carbon steel in aqueous amine for CO₂ capture. [Doctoral Dissertation]. University of Texas – Austin; 2019. Available from: http://dx.doi.org/10.26153/tsw/2683

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

University of Texas – Austin

17. -2661-6175. Influence of water on the CO₂ capture mechanism, capacity and thermodynamic properties of aprotic heterocyclic anion ionic liquids.

Degree: PhD, Chemical Engineering, 2020, University of Texas – Austin

URL: http://dx.doi.org/10.26153/tsw/9111

► Ionic liquids (ILs) are promising alternative solvents for carbon capture applications, including aprotic heterocyclic anion (AHA) ILs. These ILs were specifically designed for this application.… (more)

▼ Ionic liquids (ILs) are promising alternative solvents for carbon capture applications, including aprotic heterocyclic anion (AHA) ILs. These ILs were specifically designed for this application. They bind with CO2 in a 1 to 1 mole ratio, with a modest enthalpy of reaction. Water is an important impurity present in the flue gas, and understanding its effect is critical in designing the separation process. Water is of particular importance for ILs because it can change their physical properties and the chemistry of their reaction with CO2. In this dissertation, a comprehensive study regarding the reaction mechanism, CO2 solubility and equilibrium values of the IL-CO2-H2O system is presented. The changes in the reaction mechanism of AHA ILs with CO2 in the presence of water were investigated using NMR spectroscopy methods. It was established that in addition to the anion reacting with CO2 to form carbamate, the anion reacts with water and is reprotonated, leaving hydroxide to react with CO2 to form bicarbonate. The amount of reprotonated anion, carbamate and bicarbonate formed depends strongly on the nature of the anion and substituent groups on it. Additionally, the enthalpy, entropy and equilibrium constants for the reaction between the IL and CO2 in the presence of water were estimated. This was done by fitting experimental data of the CO2 absorption isotherms of AHA ILs and water mixtures to a Langmuir model. The results revealed that the enthalpy of the reaction leading to bicarbonate formation is larger in magnitude than the value obtained for the reaction of the neat IL with CO2 (only carbamate formation). An increase in the overall enthalpy of reaction could increase the amount of energy needed for the IL regeneration process and, subsequently, the cost of carbon capture. Nevertheless, it was concluded that water present in the post-combustion flue gas will not hinder the use of AHA ILs, in CO2 capture applications. Advisors/Committee Members: Brennecke, Joan F., 1962- (advisor), Johnston, Keith P (committee member), McCready, Mark J (committee member), Rochelle, Gary T (committee member).

Subjects/Keywords: Ionic liquids; CO2 capture; Water

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APA (6^th Edition):

-2661-6175. (2020). Influence of water on the CO₂ capture mechanism, capacity and thermodynamic properties of aprotic heterocyclic anion ionic liquids. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/9111

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Author name may be incomplete

Chicago Manual of Style (16^th Edition):

-2661-6175. “Influence of water on the CO₂ capture mechanism, capacity and thermodynamic properties of aprotic heterocyclic anion ionic liquids.” 2020. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://dx.doi.org/10.26153/tsw/9111.

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Author name may be incomplete

MLA Handbook (7^th Edition):

-2661-6175. “Influence of water on the CO₂ capture mechanism, capacity and thermodynamic properties of aprotic heterocyclic anion ionic liquids.” 2020. Web. 07 Mar 2021.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

-2661-6175. Influence of water on the CO₂ capture mechanism, capacity and thermodynamic properties of aprotic heterocyclic anion ionic liquids. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2020. [cited 2021 Mar 07]. Available from: http://dx.doi.org/10.26153/tsw/9111.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Council of Science Editors:

-2661-6175. Influence of water on the CO₂ capture mechanism, capacity and thermodynamic properties of aprotic heterocyclic anion ionic liquids. [Doctoral Dissertation]. University of Texas – Austin; 2020. Available from: http://dx.doi.org/10.26153/tsw/9111

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

University of Texas – Austin

18. Abdulla, Thaer Adnan. An experimental investigation of batch distillation column control.

Degree: PhD, Chemical Engineering, 2019, University of Texas – Austin

URL: http://dx.doi.org/10.26153/tsw/5871

► The development of an inferential soft sensor for a pilot-plant distillation column separating an ethanol-water mixture using neural network (NN) models has been investigated in… (more)

▼ The development of an inferential soft sensor for a pilot-plant distillation column separating an ethanol-water mixture using neural network (NN) models has been investigated in this work. Inferential sensors are increasingly used in the process industries to infer the value of the main quality variable while utilizing much easier to measure secondary variables of the process. The lags between the input variables and the output variables vary due to changes in operating conditions. Previous studies have introduced different methods to estimate lags for input and output variables, but all of them have assumed these lags to be constant regardless of the changes in the operating conditions. In this work, an inferential sensor that can predict the composition of ethanol at the top product using time lags for the input variables and varied first-order time constant lags with the output variable has been developed. The developed inferential sensor is based on a neural network (NN) model. Principal Component Analysis (PCA) and Projection to Latent Structures (PLS) methods are used in this work to remove the outliers from the input variables set and to determine the most correlated values of the input variables and their lags with the output variable Xa (ethanol composition of distillate product) respectively. The model adaptively selects the correct first-order time constant lags of an output variable according to the instantaneous operating condition (the composition of ethanol is increased or decreased) and assigns a best value for each case. The experimental data resulting from the operation of pilot-scale batch distillation column of ethanol-water system has been used to build these NN models first and then to validate their performance. The proposed NN model structure with time lags for input variables and varied first-order time constant lags for output variable gave higher accuracy compared with the NN model without any time lag for input and output variables. This new developed NN based soft sensor has been used in an inferential proportional-integral (PI) control scheme to control the ethanol composition of the distillate. The initial inferential control results of using one tuning parameter set during the whole operation showed imperfect control results. So, using updated tuning parameter sets (gain scheduling/adaptive tuning) within this inferential PI control scheme based on the ethanol mole fraction region is necessary to improve the control performance. The results of this new developed PI control scheme showed a good control performance compared with the initial control results of this inferential controller using one set of tuning parameters. Then, this new developed NN based soft sensor has also been used in an advanced control scheme (model predictive control or MPC scheme). Two DeltaV MPC control schemes (MPC11 and MPC22) have been developed in this work. The control results of DeltaV MPC22 control scheme showed better control performance compared with other control schemes (inferential PI and MPC11… Advisors/Committee Members: Edgar, Thomas F. (advisor), Baldea, Michael (committee member), Rochelle, Gary T. (committee member), Akella, Maruthi R. (committee member).

Subjects/Keywords: Data-driven soft sensors; ANN; Batch distillation; Inferential PI control; Model predictive control (MPC)

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APA (6^th Edition):

Abdulla, T. A. (2019). An experimental investigation of batch distillation column control. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/5871

Chicago Manual of Style (16^th Edition):

Abdulla, Thaer Adnan. “An experimental investigation of batch distillation column control.” 2019. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://dx.doi.org/10.26153/tsw/5871.

MLA Handbook (7^th Edition):

Abdulla, Thaer Adnan. “An experimental investigation of batch distillation column control.” 2019. Web. 07 Mar 2021.

Vancouver:

Abdulla TA. An experimental investigation of batch distillation column control. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2019. [cited 2021 Mar 07]. Available from: http://dx.doi.org/10.26153/tsw/5871.

Council of Science Editors:

Abdulla TA. An experimental investigation of batch distillation column control. [Doctoral Dissertation]. University of Texas – Austin; 2019. Available from: http://dx.doi.org/10.26153/tsw/5871

University of Texas – Austin

19. Ganesh, Hari Sai. Modeling, control, and optimization of an industrial austenitization furnace.

Degree: PhD, Chemical Engineering, 2019, University of Texas – Austin

URL: http://dx.doi.org/10.26153/tsw/1047

► Steel production and processing is both energy-intensive (2% of overall energy consumption) and one of the biggest contributors to CO₂ emissions. Its use is projected… (more)

▼ Steel production and processing is both energy-intensive (2% of overall energy consumption) and one of the biggest contributors to CO₂ emissions. Its use is projected to increase by 1.5 times that of present levels (around 1.6 billion metric tonnes per year) by 2050 to meet the needs of a growing population. The main goal of this research is to minimize the energy consumption of a steel quench hardening (or heat treating) process, currently in operation at an industrial partner, by mathematical modeling, optimization, advanced control, and heat integration. The quench hardening processes consists of heating pre-finished metal parts to a certain temperature in a continuously operating furnace (austenitization), followed by rapid cooling (quenching) in water, brine or oil to induce desired metallurgical properties like hardness, toughness, shear strength, tensile strength, etc. The novelty of this work lies in the two scale modeling approach considered to solve the furnace energy consumption minimization problem. We improve a previously developed two-dimensional (2D) physicsbased model of the heat treating furnace that computes the energy usage of the furnace and the part temperature distribution as a function of time and position within the furnace under temperature feedback control. We predict the effect of process variables on microstructural evolution of the parts using an empirical relation reported in the literature and their consequent effects on the metallurgical properties of the quenched product. The physics-based model combined with the empirical model is used to simulate the furnace operation for a batch of parts processed sequentially under heuristic temperature set points with a simple linear control strategy suggested by the operators of the plant. We then minimize the energy consumption of the furnace without compromising the product quality by real-time optimization (RTO), model predictive control (MPC), and heat integration using radiant recuperators. Energy savings of 3.7%, 15.93%, and 20.88% were obtained under model predictive control, heat integration, and optimized set points respectively compared to reference heuristic operation case without heat integration and MPC. Advisors/Committee Members: Baldea, Michael (advisor), Edgar, Thomas F. (advisor), Ezekoye, Ofodike A. (committee member), Rochelle, Gary T. (committee member).

Subjects/Keywords: Austenitization; Furnace; Modeling; Optimization; Control

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APA (6^th Edition):

Ganesh, H. S. (2019). Modeling, control, and optimization of an industrial austenitization furnace. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/1047

Chicago Manual of Style (16^th Edition):

Ganesh, Hari Sai. “Modeling, control, and optimization of an industrial austenitization furnace.” 2019. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://dx.doi.org/10.26153/tsw/1047.

MLA Handbook (7^th Edition):

Ganesh, Hari Sai. “Modeling, control, and optimization of an industrial austenitization furnace.” 2019. Web. 07 Mar 2021.

Vancouver:

Ganesh HS. Modeling, control, and optimization of an industrial austenitization furnace. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2019. [cited 2021 Mar 07]. Available from: http://dx.doi.org/10.26153/tsw/1047.

Council of Science Editors:

Ganesh HS. Modeling, control, and optimization of an industrial austenitization furnace. [Doctoral Dissertation]. University of Texas – Austin; 2019. Available from: http://dx.doi.org/10.26153/tsw/1047

University of Texas – Austin

20. Fulk, Steven Michael. Measuring and modeling aerosols in carbon dioxide capture by aqueous amines.

Degree: PhD, Chemical engineering, 2016, University of Texas – Austin

URL: http://hdl.handle.net/2152/41723

► Pilot scale CO2 capture plants have shown that amine condensation onto seed nuclei results in very high amine emissions which are very difficult to control… (more)

▼ Pilot scale CO2 capture plants have shown that amine condensation onto seed nuclei results in very high amine emissions which are very difficult to control using traditional aerosol removal techniques. Aerosol emissions can be suppressed by adjusting operating conditions such that drops evaporate, or, alternatively, grow to a size that can be efficiently captured by low cost methods. The effects of operating conditions on aerosol growth were investigated by experimental measurement and numerical modeling with sensitivity analyses. Total particle densities and particle size distributions (PSDs) were measured using a custom-built phase Doppler interferometer (PDI) on bench and pilot scale CO2 absorbers. Seed nuclei were generated using vaporized H2SO4, gaseous SO2, and flue gas from a coal-fired power plant. PSDs were used to calculate the aerosol amine concentration when compared to total phase (gas and aerosol) measurements collected by FTIR. The effects of operating conditions on aerosol growth were simulated in a combined heat and mass transfer model coded in MATLAB®. Aerosol transport equations included corrections for surface curvature and transport length scale regimes. Absorber and water wash models were simulated using Aspen Plus®. Inlet CO2 is crucial in creating supersaturation in the absorber; the loading difference between the aerosol and bulk solvent creates an amine driving force for condensation. Aerosols grow faster in non-intercooled columns due to differences in solvent composition (CO2 loading) and temperature. H2O condensation is the primary growth mechanism in the water wash. Reducing the water wash amine concentration and providing additional residence time leads to more aerosol growth. Doubling the water wash height results in a 13.7 % increase in the final aerosol diameter for a generic 8 m PZ absorber. Similar to some other volatile amines, PZ forms 1–5 μm aerosols because its amine volatility is a strong function of CO2 loading. The amine concentration in measured aerosol distributions, calculated by PDI/FTIR comparison, was one-to-two orders of magnitude lower than the bulk solvent. SO2 forms aerosol with PZ. 65 % of injected SO2 leaves in the aerosol phase. Therefore, SO2 polishing scrubbers are essential and systems should not be designed for simultaneous absorption of CO2 and SO2. Advisors/Committee Members: Rochelle, Gary T. (advisor), Bonnecaze, Roger T (committee member), Chen, Eric (committee member), Hildebrandt Ruiz, Lea (committee member), McDonald-Buller, Elena (committee member).

Subjects/Keywords: Carbon dioxide capture; Aerosols; Amines; Phase doppler interferometry

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APA (6^th Edition):

Fulk, S. M. (2016). Measuring and modeling aerosols in carbon dioxide capture by aqueous amines. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/41723

Chicago Manual of Style (16^th Edition):

Fulk, Steven Michael. “Measuring and modeling aerosols in carbon dioxide capture by aqueous amines.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/41723.

MLA Handbook (7^th Edition):

Fulk, Steven Michael. “Measuring and modeling aerosols in carbon dioxide capture by aqueous amines.” 2016. Web. 07 Mar 2021.

Vancouver:

Fulk SM. Measuring and modeling aerosols in carbon dioxide capture by aqueous amines. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/41723.

Council of Science Editors:

Fulk SM. Measuring and modeling aerosols in carbon dioxide capture by aqueous amines. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/41723

21. -5585-894X. Aerosol measurement and mitigation in CO₂ capture by amine scrubbing.

Degree: PhD, Chemical Engineering, 2018, University of Texas – Austin

URL: http://hdl.handle.net/2152/67989

► Amine solvent losses are a significant issue for CO₂ capture by amine scrubbing. Solvent lost through aerosol emission represents an environmental hazard with adverse economic… (more)

▼ Amine solvent losses are a significant issue for CO₂ capture by amine scrubbing. Solvent lost through aerosol emission represents an environmental hazard with adverse economic implications. This research focuses on developing analytical systems to quantify amine aerosol emissions. Fourier Transform Infrared Spectrometry quantified amine emissions and Phase Doppler Interferometry determined aerosol size and concentration. Baghouse pretreatment of the flue gas significantly reduced amine emissions through collection of aerosol nuclei. A baghouse at the National Carbon Capture Center (NCCC) reduced monoethanolamine (MEA) emission by over a factor of 10. An SO₃ generator was built to facilitate bench and pilot scale aerosol experiments by reacting SO₂ in air over vanadium pentoxide catalyst at 520 °C. Aerosol generation at UT-SRP produced up to 1.7 grams per minute of SO₃, with conversion exceeding 81 %. Bench scale experiments achieved conversion greater than 97 % and aerosol concentration up to 7E4 cm⁻³. SO₃ increased piperazine (PZ) emission by up to 7.6 mol PZ/ mol SO₃. SO₂ increased PZ emission by 1 mol/ mol SO₂, and increased MEA emissions by 3.9 mol/ mol SO₂. H₂SO₄ increased PZ emission by 3 mol/ mol H₂SO₄. PZ resisted aerosol emissions with lower SO₃ content; this is because a low inlet aerosol nuclei concentration results in rapid aerosol growth and subsequent collection by impaction. Higher process temperatures correlated with decreasing PZ emission, supporting the growth and capture theory. Increasing the solvent PZ content was shown to strongly correlate with increasing PZ emission. In bench scale experiments, PZ emission and aerosol size both increased as the PZ content in the solvent increased. Lowering the temperature bulge stage reduced PZ emission and the aerosol size. Increasing the inlet CO₂ correlated with larger aerosol. Increasing the solvent CO₂ loading and the inlet SO₃ resulted in greater aerosol concentration. Operations with a blower upstream of the absorber increased MEA aerosol emission. The upstream blower resulted in larger aerosol in greater quantities, containing a greater quantity of MEA Reduced MEA emission with an intermediate blower are probably due to collection of aerosol through impaction within the blower. Advisors/Committee Members: Rochelle, Gary T. (advisor), Chen, Eric (committee member), Bonnecaze, Roger T (committee member), Hildebrant Ruiz, Lea (committee member), Knuutila, Hanna (committee member).

Subjects/Keywords: Amine aerosol; CO2 capture; Pilot plant; FTIR; PDI

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APA (6^th Edition):

-5585-894X. (2018). Aerosol measurement and mitigation in CO₂ capture by amine scrubbing. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/67989

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Author name may be incomplete

Chicago Manual of Style (16^th Edition):

-5585-894X. “Aerosol measurement and mitigation in CO₂ capture by amine scrubbing.” 2018. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/67989.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

MLA Handbook (7^th Edition):

-5585-894X. “Aerosol measurement and mitigation in CO₂ capture by amine scrubbing.” 2018. Web. 07 Mar 2021.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

-5585-894X. Aerosol measurement and mitigation in CO₂ capture by amine scrubbing. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2018. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/67989.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Council of Science Editors:

-5585-894X. Aerosol measurement and mitigation in CO₂ capture by amine scrubbing. [Doctoral Dissertation]. University of Texas – Austin; 2018. Available from: http://hdl.handle.net/2152/67989

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

University of Texas – Austin

22. Pattison, Richard C. Equation-oriented modeling, simulation, and optimization of integrated and intensified process and energy systems.

Degree: PhD, Chemical engineering, 2016, University of Texas – Austin

URL: http://hdl.handle.net/2152/46459

► Process intensification, defined as unconventional design and/or operation of processes that results in substantial performance improvements, represents a promising route toward reducing capital and operating… (more)

▼ Process intensification, defined as unconventional design and/or operation of processes that results in substantial performance improvements, represents a promising route toward reducing capital and operating expenses in the chemical/petrochemical process industry, while simultaneously achieving improved safety and environmental performance. In this dissertation, intensification is approached from three different angles: reactor design and control, process flowsheet design and optimization, and production scheduling and control. In the first part of the dissertation, three novel concepts for improving the controllability of intensified microchannel reactors are introduced. The first concept is a latent energy storage-based temperature controller, where a phase change material is confined within the walls of an autothermal reactor to improve local temperature control. The second concept is a segmented catalyst layer which modulates the rate of heat generation and consumption along the length of an autothermal reactor. Finally, the third concept is a thermally actuated valve, which uses small-scale bimetallic strips to modulate flow in a microchannel reactor in response to temperature changes. The second part of the dissertation introduces a novel framework for equation-oriented flowsheet modeling, simulation and optimization. The framework consists of a pseudo-transient reformulation of the steady-state material and energy balance equations of process unit operations as differential-algebraic equation (DAE) systems that are statically equivalent to the original model. I show that these pseudo-transient models improve the convergence properties of equation-oriented process flowsheet simulations by expanding the convergence basin in comparison to conventional steady state equation-oriented simulators. A library of pseudo-transient unit operation models is developed, and several case studies are presented. Models for more complex unit operations such as a pseudo-transient multistream heat exchanger and a dividing-wall distillation column are later introduced, and can easily be included in the flowsheet optimization framework. In the final part of the dissertation, a paradigm for calculating the optimal production schedule in a fast changing market situation is introduced. This is accomplished by including a model of the dynamics of a process and its control system into production scheduling calculations. The scheduling-relevant dynamic models are constructed to be of lower order than a detailed dynamic process model, while capturing the closed-loop behavior of a set of scheduling-relevant variables. Additionally, a method is given for carrying out these production scheduling calculations online and in "closed scheduling loop,"' i.e., recalculating scheduling decisions upon the advent of scheduling-relevant process or market events. An air separation unit operating in a demand response scenario is used as a representative case study. Advisors/Committee Members: Baldea, Michael (advisor), Edgar, Thomas F. (committee member), Rochelle, Gary T (committee member), Bonnecaze, Roger T (committee member), Biros, George (committee member).

Subjects/Keywords: Process modeling; Process control; Flowsheet optimization; Integration of scheduling and control; Equation-oriented modeling; Process intensification; Process integration

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APA (6^th Edition):

Pattison, R. C. (2016). Equation-oriented modeling, simulation, and optimization of integrated and intensified process and energy systems. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/46459

Chicago Manual of Style (16^th Edition):

Pattison, Richard C. “Equation-oriented modeling, simulation, and optimization of integrated and intensified process and energy systems.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/46459.

MLA Handbook (7^th Edition):

Pattison, Richard C. “Equation-oriented modeling, simulation, and optimization of integrated and intensified process and energy systems.” 2016. Web. 07 Mar 2021.

Vancouver:

Pattison RC. Equation-oriented modeling, simulation, and optimization of integrated and intensified process and energy systems. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/46459.

Council of Science Editors:

Pattison RC. Equation-oriented modeling, simulation, and optimization of integrated and intensified process and energy systems. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/46459

University of Texas – Austin

23. Park, Jungup. Data-driven modeling and optimization of sequential batch-continuous process.

Degree: PhD, Chemical engineering, 2016, University of Texas – Austin

URL: http://hdl.handle.net/2152/39461

► Driven by the need to lower capital expenditures and operating costs, as well as by competitive pressure to increase product quality and consistency, modern chemical… (more)

▼ Driven by the need to lower capital expenditures and operating costs, as well as by competitive pressure to increase product quality and consistency, modern chemical processes have become increasingly complex. These trends are manifest, on the one hand, in complex equipment configurations and, on the other hand, in a broad array of sensors (and control systems), which generate large quantities of operating data. Of particular interest is the combination of two traditional routes of chemical processing: batch and continuous. Batch to continuous processes (B2C), which constitute the topic of this dissertation, comprise of a batch section, which is responsible for preparing the materials that are then processed in the continuous section. In addition to merging the modeling, control and optimization approaches related to the batch and continuous operating paradigms – which are radically different in many aspects – challenges related to analyzing the operation of such processes arise from the multi-phase flow. In particular, we will be considering the case where a particulate solid is suspended in a liquid ``carrier'', in the batch stage, and the two-phase mixture is conveyed through the continuous stage. Our explicit goal is to provide a complete operating solution for such processes, starting with the development of meaningful and computationally efficient mathematical models, continuing with a control and fault detection solution, and finally, a production scheduling concept. Owing to process complexity, we reject out of hand the use of first-principles models, which are inevitably high dimensional and computationally expensive, and focus on data-driven approaches instead. Raw data obtained from chemical industry are subject to noise, equipment malfunction and communication failures and, as such, data recorded in process historian databases may contain outliers and measurement noise. Without proper pretreatment, the accuracy and performance of a model derived from such data may be inadequate. In the next chapter of this dissertation, we address this issue, and evaluate several data outlier removal techniques and filtering methods using actual production data from an industrial B2C system. We also address a specific challenge of B2C systems, that is, synchronizing the timing of the batch data need with the data collected from the continuous section of the process. Variable-wise unfolded data (a typical approach for batch processes) exhibit measurement gaps between the batches; however, this type of behavior cannot be found in the subsequent continuous section. These data gaps have an impact on data analysis and, in order to address this issue, we provide a method for filling in the missing values. The batch characteristic values are assigned in the gaps to match the data length with the continuous process, a procedure that preserves meaningful process correlations. Data-driven modeling techniques such as principal component analysis (PCA) and partial least squares (PLS) regression are well-established for modeling batch… Advisors/Committee Members: Edgar, Thomas F. (advisor), Baldea, Michael (advisor), Djurdjanovic, Dragan (committee member), Rochelle, Gary T (committee member), Truskett, Thomas M (committee member).

Subjects/Keywords: Sequential batch-continuous process; Data-driven modeling; Time scale bridging model; Scheduling; Control; Real-time optimization

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APA (6^th Edition):

Park, J. (2016). Data-driven modeling and optimization of sequential batch-continuous process. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/39461

Chicago Manual of Style (16^th Edition):

Park, Jungup. “Data-driven modeling and optimization of sequential batch-continuous process.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/39461.

MLA Handbook (7^th Edition):

Park, Jungup. “Data-driven modeling and optimization of sequential batch-continuous process.” 2016. Web. 07 Mar 2021.

Vancouver:

Park J. Data-driven modeling and optimization of sequential batch-continuous process. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/39461.

Council of Science Editors:

Park J. Data-driven modeling and optimization of sequential batch-continuous process. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/39461

University of Texas – Austin

24. Chen, Xi, 1981-. Carbon dioxide thermodynamics, kinetics, and mass transfer in aqueous piperazine derivatives and other amines.

Degree: PhD, Chemical Engineering, 2011, University of Texas – Austin

URL: http://hdl.handle.net/2152/ETD-UT-2011-08-4312

► To screen amine solvents for application in CO2 capture from coal-fired power plants, the equilibrium CO2 partial pressure and liquid film mass transfer coefficient were… (more)

▼ To screen amine solvents for application in CO2 capture from coal-fired power plants, the equilibrium CO2 partial pressure and liquid film mass transfer coefficient were characterized for CO2-loaded and highly concentrated aqueous amines at 40 – 100 °C over a range of CO2 loading with a Wetted Wall Column (WWC). The acyclic amines tested were ethylenediamine, 1,2-diaminopropane, diglycolamine®, methyldiethanolamine (MDEA)/Piperazine (PZ), 3-(methylamino)propylamine, 2-amino-2-methyl-1-propanol and 2-amino-2-methyl-1-propanol/PZ. The cyclic amines tested were piperazine derivatives including proline, 2-piperidineethanol, N-(2-hydroxyethyl)piperazine, 1-(2-aminoethyl)piperazine, N-methylpiperazine (NMPZ), 2-methylpiperazine (2MPZ), 2,5-trans-dimethylpiperazine, 2MPZ/PZ, and PZ/NMPZ/1,4-dimethylpiperazine (1,4-DMPZ). The cyclic CO2 capacity and heat of CO2 absorption were estimated with a semi-empirical vapor-liquid-equilibrium model. 5 m MDEA/5 m PZ, 8 m 2MPZ, 4 m 2MPZ/4 m PZ and 3.75 m PZ/3.75 m NMPZ/0.5 m 1,4-DMPZ were identified as promising solvent candidates for their large CO2 capacity, fast mass transfer rate and moderately high heat of absorption. The speciation in 8 m 2MPZ and 4 m 2MPZ / 4 m PZ at 40 °C at varied CO2 loading was investigated using quantitative 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. In 8 m 2MPZ at 40 °C over the CO2 loading range of 0 – 0.37 mol CO2/mol alkalinity, more than 75% of the dissolved CO2 exists in the form of unhindered 2MPZ monocarbamate, and the rest is in the form of bicarbonate and dicarbamate; 19% - 56% of 2MPZ is converted to 2MPZ carbamate at 0.1 - 0.37 mol CO2/mol alkalinity. A rigorous thermodynamic model was developed for 8 m 2MPZ in the framework of the Electrolyte Nonrandom Two-Liquid (ENRTL) model. At 40 °C, the reaction stoichiometry for 2MPZ and CO2 is around 2 at lean loading but diminishes to 0 at rich loading. Bicarbonate becomes the major product at CO2 loading greater than 0.35 mol/mol alkalinity. The predicted heat of CO2 absorption is 75 kJ/mol at 140 °C and decreases with temperature when CO2 loading is above 0.25. The mass transfer rate data for 8 m 2MPZ was represented with a rate-based WWC model created in Aspen Plus®. The reaction rate was described with termolecular mechanism on an activity basis. With minor CO2 loading adjustment and regression of pre-exponential kinetic constants and diffusion activation energy, a majority of the measured CO2 fluxes in the WWC experiments were fitted by the model within ±20% over 40 – 100 °C and 0.1 – 0.37 mol CO2/mol alkalinity. The diffusion activation energy for 8 m 2MPZ at the rich loading is about 28 kJ/mol. The activity-based reaction rate constant at 40 °C for 2MPZ carbamate formation catalyzed by 2MPZ is 1.94×1010 kmol/m3•s. The calculated liquid film mass transfer coefficients are in close agreement with the experimental values. The liquid film mass transfer rate is dependent on the diffusion coefficients of amine and CO2 to the same extent at lean loading and 40 °C. The sum… Advisors/Committee Members: Rochelle, Gary T. (advisor), Alper, Hal S. (committee member), Bryant, Steven L. (committee member), Korgel, Brian A. (committee member), Ganesan, Venkat (committee member).

Subjects/Keywords: Piperazine derivatives; Carbon dioxide solubility; Liquid film mass transfer coefficient; Heat of absorption

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APA (6^th Edition):

Chen, Xi, 1. (2011). Carbon dioxide thermodynamics, kinetics, and mass transfer in aqueous piperazine derivatives and other amines. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2011-08-4312

Chicago Manual of Style (16^th Edition):

Chen, Xi, 1981-. “Carbon dioxide thermodynamics, kinetics, and mass transfer in aqueous piperazine derivatives and other amines.” 2011. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/ETD-UT-2011-08-4312.

MLA Handbook (7^th Edition):

Chen, Xi, 1981-. “Carbon dioxide thermodynamics, kinetics, and mass transfer in aqueous piperazine derivatives and other amines.” 2011. Web. 07 Mar 2021.

Vancouver:

Chen, Xi 1. Carbon dioxide thermodynamics, kinetics, and mass transfer in aqueous piperazine derivatives and other amines. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2011. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/ETD-UT-2011-08-4312.

Council of Science Editors:

Chen, Xi 1. Carbon dioxide thermodynamics, kinetics, and mass transfer in aqueous piperazine derivatives and other amines. [Doctoral Dissertation]. University of Texas – Austin; 2011. Available from: http://hdl.handle.net/2152/ETD-UT-2011-08-4312

University of Texas – Austin

25. -1081-1133. Mass transfer rate in semi-aqueous amines for CO₂ capture: Mass transfer rate in semi-aqueous amines for carbon dioxide capture.

Degree: PhD, Chemical Engineering, 2018, University of Texas – Austin

URL: http://hdl.handle.net/2152/70605

► Amine scrubbing is the most promising solution to address CO₂ emission from power plants. Solvent development can significantly reduce the capital and energy cost of… (more)

▼ Amine scrubbing is the most promising solution to address CO₂ emission from power plants. Solvent development can significantly reduce the capital and energy cost of the process. This work rigorously studies the CO₂ mass transfer and solubility at flue gas treating process condition for aqueous and semi-aqueous amines. A second-generation aqueous amine solvent: 2methylpiperazine (2MPZ) blended with piperazine (PZ) that has been developed with good overall performance. The effect of viscosity on absorption rate and heat exchanger has been identified. Optimal concentration for 2MPZ/PZ is found to be 5 m (5 mole/kg water). Thermodynamic and kinetic model has been developed for 2MPZ/PZ in Aspen Plus to allow economic assessments, and process modeling. Semi-aqueous MEA/PZ composes of physical solvent, water, and amine has been characterized. Ultra-fast absorption rate at lean loading has been achieved. The effect of viscosity, diffusivity, CO₂ activity (physical solubility), and amine activity on mass transfer rate (kg') has been studied. kg' increases because of reduced operating CO₂ loading (higher MEA concentration at the same P [superscript *] [subscript CO2]), greater CO₂ physical solubility, and greater MEA activity. The increase in kg' becomes less significant at higher loading due to low diffusivity by high viscosity. The mass transfer model of CO₂ diffusion and reaction with semi-aqueous MEA was built in MATLAB [superscript ®]. Sensitive analysis shows the relationship between rate and solvent physical/thermal properties. The pseudo first order approximation is not applicable to semi-aqueous MEA because of surface depletion of MEA. The energy use of CO₂ capture by amine scrubbing can be estimated by adding minimum work and lost work. Semi-aqueous amines reduces the lost work in the condenser due to less water evaporation in the stripper, which. However; second generation amine processes use advanced stripper configurations can accomplish the same effect with little additional capital cost. Besides viscosity, thermal conductivity and heat capacity also effect the heat exchanger cost. Comprehensive normalized capacity has been developed. An advanced solvent with high normalized capacity can reduce the CAPEX/OPEX of the heat exchanger no matter the solvent is water lean or not. [Mathematical equation]. Advisors/Committee Members: Rochelle, Gary T. (advisor), Sanchez, Isaac C. (committee member), Hwang, Gyeong S. (committee member), Dugas, Ross E. (committee member).

Subjects/Keywords: Carbon capture; Mass transfer

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APA (6^th Edition):

-1081-1133. (2018). Mass transfer rate in semi-aqueous amines for CO₂ capture: Mass transfer rate in semi-aqueous amines for carbon dioxide capture. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/70605

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Chicago Manual of Style (16^th Edition):

-1081-1133. “Mass transfer rate in semi-aqueous amines for CO₂ capture: Mass transfer rate in semi-aqueous amines for carbon dioxide capture.” 2018. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/70605.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

MLA Handbook (7^th Edition):

-1081-1133. “Mass transfer rate in semi-aqueous amines for CO₂ capture: Mass transfer rate in semi-aqueous amines for carbon dioxide capture.” 2018. Web. 07 Mar 2021.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

-1081-1133. Mass transfer rate in semi-aqueous amines for CO₂ capture: Mass transfer rate in semi-aqueous amines for carbon dioxide capture. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2018. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/70605.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Council of Science Editors:

-1081-1133. Mass transfer rate in semi-aqueous amines for CO₂ capture: Mass transfer rate in semi-aqueous amines for carbon dioxide capture. [Doctoral Dissertation]. University of Texas – Austin; 2018. Available from: http://hdl.handle.net/2152/70605

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

University of Texas – Austin

26. Torres López, David Enrique. Enhancing the productivity of volatile oil reservoirs using fluorinated chemical treatments.

Degree: PhD, Chemical Engineering, 2011, University of Texas – Austin

URL: http://hdl.handle.net/2152/ETD-UT-2011-08-4253

► Many producing volatile oil reservoirs experience a significant decrease in well deliverability when the bottom-hole pressure of the well falls below the bubble point pressure.… (more)

▼ Many producing volatile oil reservoirs experience a significant decrease in well deliverability when the bottom-hole pressure of the well falls below the bubble point pressure. This is due to the liberation of a gas phase which resides in the pore space and blocks the flow of the oil phase. This situation is known as "gas blocking". This occurs because the presence of two or three immiscible phases (gas, oil and water) results in a reduction of the oil saturation and a decrease in the oil relative permeability. The main objective of this research was to develop an effective and durable chemical treatment method to improve and/or restore the productivity of volatile oil wells undergoing "gas blocking". The treatment method is based on the use of fluorinated surfactants in tailored solvents to increase the oil relative permeability by changing the wettability of the rock’s surface. High-temperature high-pressure (HTHP) core flood experiments were used to evaluate the uses of fluorinated surfactants under reservoir conditions. Analytical tools such as X-ray photoelectron spectroscopy (XPS), high-performance liquid chromatography (HPLC) and computerized axial tomography (CT Scan) were also used to interpret the experimental results. High-pressure high-temperature (HPHT) coreflood tests showed that the treatments improved the oil and gas relative permeability in both sandstone and limestone cores. This was observed for synthetic volatile oil mixtures with gas-oil ratios (GOR) in the range of 4000 to 13,000 scf/STB at low capillary numbers (Nc) on the order of 1x10-5 to 1x10-6 and for PVT ratios greater than 0.5. The fluorinated chemical treatments were effective in the presence of connate water over the temperature range of 155°F to 275°F. Wettability alteration was measured using contact angle and imbibition rate tests. Results from analytical tools showed that fluorinated surfactants were uniformly adsorbed along the core and the surfactant desorption after treatment was low (10 ppm or less). The gas saturation decreased following treatment and both the oil and gas relative permeability increased. Numerical simulations using the measured relative permeability data were used to estimate the gain in productivity for treated wells. The proposed fluorinated chemical treatments could be used as a preventive treatment or for a damaged well that has already been producing below the bubble point to increase oil production rates and recoverable reserves. Advisors/Committee Members: Sharma, Mukul M. (advisor), Pope, Gary A. (advisor), Rochelle, Gary T. (committee member), Bonnecaze, Roger T. (committee member), Freeman, Benny D. (committee member).

Subjects/Keywords: Volatile oil; Fluorinated surfactants; Gas blocking; Wettability alteration

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APA (6^th Edition):

Torres López, D. E. (2011). Enhancing the productivity of volatile oil reservoirs using fluorinated chemical treatments. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2011-08-4253

Chicago Manual of Style (16^th Edition):

Torres López, David Enrique. “Enhancing the productivity of volatile oil reservoirs using fluorinated chemical treatments.” 2011. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/ETD-UT-2011-08-4253.

MLA Handbook (7^th Edition):

Torres López, David Enrique. “Enhancing the productivity of volatile oil reservoirs using fluorinated chemical treatments.” 2011. Web. 07 Mar 2021.

Vancouver:

Torres López DE. Enhancing the productivity of volatile oil reservoirs using fluorinated chemical treatments. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2011. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/ETD-UT-2011-08-4253.

Council of Science Editors:

Torres López DE. Enhancing the productivity of volatile oil reservoirs using fluorinated chemical treatments. [Doctoral Dissertation]. University of Texas – Austin; 2011. Available from: http://hdl.handle.net/2152/ETD-UT-2011-08-4253

University of Texas – Austin

27. -3170-9069. Absorber and aerosol modeling in amine scrubbing for carbon capture.

Degree: PhD, Chemical Engineering, 2018, University of Texas – Austin

URL: http://hdl.handle.net/2152/71424

► A rate-based PZ aerosol growth model was developed in gPROMS [superscript ®] ModelBuilder. Amine Aerosol growth was simulated at the unique conditions of piperazine (PZ)… (more)

▼ A rate-based PZ aerosol growth model was developed in gPROMS [superscript ®] ModelBuilder. Amine Aerosol growth was simulated at the unique conditions of piperazine (PZ) and the pilot plant absorber configurations at the National Carbon Capture Center. Amine aerosol growth is driven by amine-limited diffusion. As aerosol concentration increases, aerosol growth decreases due to the depletion of the amine driving force in the gas phase. Aerosol growth can be increased by enhancing the gas-film mass transfer coefficient of packing. A solvent with moderate volatility, like PZ, will produce aerosol that grows to larger size and is easier to collect. Solvents with low volatility should be avoided as they produce aerosol that is hard to collect. Process configurations that provide greater water partial pressure in the water wash, such as higher operating temperature and pre-humidified empty space, will help aerosol grow. Two pilot plant campaigns were designed and conducted in this work. 5 molal (m) PZ was operated for the first time and provided significant absorber performance benefits over 8 m PZ due to enhanced mass transfer rates from lower solvent viscosity. Parametric tests were performed with a wide range of absorber operating conditions. With the existing model correction, the pilot plant absorber model could reasonably capture the measured absorber performance. For future campaigns, this work recommended that the pilot plant absorber should be operated at both pinched and not pinched conditions. Both equilibrium correction (correct for errors in solvent loading measurements and effects of degradation) and packing correction (correct for effects of rivulets and drop and additional mass transfer caused by distributors and chimney trays) should be utilized in the data reconciliation process. A membrane-amine hybrid carbon capture system for natural gas combined cycle (NGCC) power plants was proposed and evaluated. When the inlet CO2 increases from 4% to 18%, the total absorption costs decrease by 60% and the total regeneration costs remain the same. Amine scrubbing without the direct contact cooler was found to be a superior design for NGCC carbon capture. The absorber gas inlet must be designed to avoid excessive localized temperature and solvent evaporation. Advisors/Committee Members: Rochelle, Gary T. (advisor), Hildebrandt Ruiz, Lea (committee member), Bonnecaze, Roger (committee member), Svendsen , Hallvard (committee member).

Subjects/Keywords: Absorber; Aerosol

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APA (6^th Edition):

-3170-9069. (2018). Absorber and aerosol modeling in amine scrubbing for carbon capture. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/71424

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Chicago Manual of Style (16^th Edition):

-3170-9069. “Absorber and aerosol modeling in amine scrubbing for carbon capture.” 2018. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/71424.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

MLA Handbook (7^th Edition):

-3170-9069. “Absorber and aerosol modeling in amine scrubbing for carbon capture.” 2018. Web. 07 Mar 2021.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

-3170-9069. Absorber and aerosol modeling in amine scrubbing for carbon capture. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2018. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/71424.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Council of Science Editors:

-3170-9069. Absorber and aerosol modeling in amine scrubbing for carbon capture. [Doctoral Dissertation]. University of Texas – Austin; 2018. Available from: http://hdl.handle.net/2152/71424

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

University of Texas – Austin

28. Sherman, Brent Joseph. Thermodynamic and mass transfer modeling of aqueous hindered amines for carbon dIoxide capture.

Degree: PhD, Chemical engineering, 2016, University of Texas – Austin

URL: http://hdl.handle.net/2152/39630

► With the detrimental effects of global climate change beginning to be felt, there is a growing consensus that something must be done. One part of… (more)

▼ With the detrimental effects of global climate change beginning to be felt, there is a growing consensus that something must be done. One part of the solution is carbon capture and storage using amine scrubbing to capture 90% of the CO2 from power plants burning coal and natural gas. To actualize this solution, process models are necessary. A process model requires an accurate thermodynamic and mass transfer model with physically meaningful parameters. While hindered amines are commercially used, the reason for their mass transfer rates is still an open question. These two needs are addressed in this work. To improve thermodynamic modeling, the physical significance of the electrolyte non-random two-liquid (eNRTL) regressed binary interaction parameters were examined. To improve mass transfer modeling, a response surface methodology (RSM) approach was used to give statistically significant regressed parameters. The mass transfer of two hindered amines, 2-amino-2-methyl-propan-1-ol (AMP) and 2-piperidineethanol (2PE) was studied to determine the role of carbamate. The absolute difference in eNRTL binary interaction parameters was found to moderately correlate with the pKa of the amine. An analogy method was developed to enable thermodynamic model creation for amines in the absence of some physical property data. The carbamate reaction plays a determining role in mass transfer of hindered amines. Based on Bronsted plots, 2PE appears to form carbamate using the same mechanism as unhindered, cyclic secondary amines, while AMP does not seem to use the same mechanism as unhindered, primary amines. The rate constant for bicarbonate formation for both amines is a factor of twelve faster than predicted from tertiary amine bicarbonate formation, indicating that neither seems to form bicarbonate using the tertiary amine mechanism. The six models constructed in this work enable process modeling and economic comparisons of solvents. Four binary interaction parameters were the most physically significant and should be regressed for future solvents. The high bicarbonate reaction rate of the hindered amines should be further investigated to determine if the mechanism is different or if this is model artifice, as either outcome will substantially improve mass transfer modeling for all amines. Advisors/Committee Members: Rochelle, Gary T. (advisor), Baldea, Michael (committee member), Chen, Chau-Chyun (committee member), Chen, Eric (committee member), Hwang, Gyeong (committee member).

Subjects/Keywords: eNRTL; Separations; Carbamate stability; Wetted-wall column; Blend solvent; Amine scrubbing

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sherman, B. J. (2016). Thermodynamic and mass transfer modeling of aqueous hindered amines for carbon dIoxide capture. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/39630

Chicago Manual of Style (16^th Edition):

Sherman, Brent Joseph. “Thermodynamic and mass transfer modeling of aqueous hindered amines for carbon dIoxide capture.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/39630.

MLA Handbook (7^th Edition):

Sherman, Brent Joseph. “Thermodynamic and mass transfer modeling of aqueous hindered amines for carbon dIoxide capture.” 2016. Web. 07 Mar 2021.

Vancouver:

Sherman BJ. Thermodynamic and mass transfer modeling of aqueous hindered amines for carbon dIoxide capture. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/39630.

Council of Science Editors:

Sherman BJ. Thermodynamic and mass transfer modeling of aqueous hindered amines for carbon dIoxide capture. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/39630

University of Texas – Austin

29. Sachde, Darshan Jitendra. Absorber performance and configurations for CO2 capture using aqueous piperazine.

Degree: PhD, Chemical engineering, 2016, University of Texas – Austin

URL: http://hdl.handle.net/2152/39631

► Absorber design for CO2 capture with amine solvents is complicated by the presence of temperature gradients and multiple rate controlling mechanisms (chemical reaction and convective… (more)

▼ Absorber design for CO2 capture with amine solvents is complicated by the presence of temperature gradients and multiple rate controlling mechanisms (chemical reaction and convective mass transfer). The development of rigorous rate-based models has created the opportunity to study the performance limiting mechanisms in detail. A structured approach was developed to validate absorber models, identify limiting phenomena, and develop configurations that specifically address limiting mechanisms. A rate-based model utilizing concentrated aqueous piperazine (PZ) was the focus of model validation and process development. The model was validated using pilot plant data, matching the number of transfer units (NTU) within + 1% while identifying a systematic bias (loading measurement) between the model and pilot plant data. The validated model was used to define limiting cases (isothermal and adiabatic absorbers) to study the effects of operating conditions on the formation of temperature-induced mass transfer pinches. The method allowed for screening of intercooling benefits – high CO2 applications (15% - 27% CO2) require intercooling over the entire practical loading range for PZ and benefit significantly from simple in-and-out intercooling with limited additional benefit expected from advanced design. Low CO2 (4% CO2) applications are expected to benefit the most from improved intercooling, but also have the largest operating window without the need for intercooling (< 0.22 mol CO2/mol alkalinity for 8 m PZ). An analogous approach was developed to study rate mechanisms. A mass transfer parameter sensitivity analysis approach was developed to identify the relative contribution to overall mass transfer resistance of each mechanism as a function of operating conditions and position in the absorber column. The pseudo-first order and instantaneous reaction asymptotic solutions to the reaction-diffusion problem were used to define a dimensionless parameter that quantifies the approach of the modeling results to the limiting conditions and was found to be predictive of the relative liquid film resistance (diffusion vs. reaction) at all conditions. The results of the analysis indicated that the absorber is strongly diffusion controlled, has limited gas-film resistance, and that equilibrium constraints at the rich end of the absorber (depletion of free amine) significantly increase diffusion limitations. Finally, the validation and mechanistic studies provided the basis for four new absorber configurations: 1) integration of a spray nozzle in the intercooling loop, 2) solvent recycle intercooling, 3) integrated flue gas and solvent cooling functions, 4) hybrid intercooling (high intensity contacting with intercooling). Each approach coupled mass transfer enhancement with intercooling and provided new degrees of freedom for operation and design of absorbers for CO2 capture. Advisors/Committee Members: Rochelle, Gary T. (advisor), Baldea, Michael (committee member), Bhown, Abhoyjit (committee member), Chen, Eric (committee member), Hwang, Gyeong (committee member).

Subjects/Keywords: CO2 capture; Piperazine; Absorber; Amine scrubbing; Mass transfer; Intercooling

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sachde, D. J. (2016). Absorber performance and configurations for CO2 capture using aqueous piperazine. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/39631

Chicago Manual of Style (16^th Edition):

Sachde, Darshan Jitendra. “Absorber performance and configurations for CO2 capture using aqueous piperazine.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/39631.

MLA Handbook (7^th Edition):

Sachde, Darshan Jitendra. “Absorber performance and configurations for CO2 capture using aqueous piperazine.” 2016. Web. 07 Mar 2021.

Vancouver:

Sachde DJ. Absorber performance and configurations for CO2 capture using aqueous piperazine. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/39631.

Council of Science Editors:

Sachde DJ. Absorber performance and configurations for CO2 capture using aqueous piperazine. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/39631

University of Texas – Austin

30. Freeman, Stephanie Anne. Thermal degradation and oxidation of aqueous piperazine for carbon dioxide capture.

Degree: PhD, Chemical Engineering, 2011, University of Texas – Austin

URL: http://hdl.handle.net/2152/ETD-UT-2011-05-3290

► Absorption-stripping with aqueous, concentrated piperazine (PZ) is a viable retrofit technology for post-combustion CO2 capture from coal-fired power plants. The rate of thermal degradation and… (more)

▼ Absorption-stripping with aqueous, concentrated piperazine (PZ) is a viable retrofit technology for post-combustion CO2 capture from coal-fired power plants. The rate of thermal degradation and oxidation of PZ was investigated over a range of temperature, CO2 loading, and PZ concentration. At 135 to 175 °C, degradation is first order in PZ with an activation energy of 183.5 kJ/mole. At 150 °C, the first order rate constant, k1, for thermal degradation of 8 m PZ with 0.3 mol CO2/mol alkalinity is 6.12 × 10-9 s-1. After 20 weeks of degradation at 165 °C, 74% and 63%, respectively, of the nitrogen and carbon lost in the form of PZ and CO2 was recovered in quantifiable degradation products. N-formylpiperazine, ammonium, and N-(2-aminoethyl) piperazine account for 57% and 45% of nitrogen and carbon lost, respectively. Thermal degradation of PZ likely proceeds through SN2 substitution reactions. In the suspected first step of the mechanism, 1-[2-[(2-aminoethyl) amino]ethyl] PZ is formed from a ring opening SN2 reaction of PZ with H+PZ. Formate was found to be generated during thermal degradation from CO2 or CO2-containing molecules. An analysis of k1 values was applied to a variety of amines screened for thermal stability in order to predict a maximum recommended stripper temperature. Morpholine, piperidine, PZ, and PZ derivatives were found to be the most stable with an allowable stripper temperature above 160 °C. Long-chain alkyl amines or alkanolamines such as N-(2-hydroxyethyl)ethylenediamine and diethanolamine were found to be the most unstable with an allowable stripper temperature below 120 °C. Iron (Fe2+) and stainless steel metals (Fe2+, Ni2+, and Cr3+) were found to be only weak catalysts for oxidation of PZ, while oxidation was rapidly catalyzed by copper (Cu2+). In a system with Fe2+ or SSM, 5 kPa O2 in the inlet flue gas, a 55 °C absorber, and one-third residence time with O2, the maximum loss rate of PZ is expected to 0.23 mol PZ/kg solvent in one year of operation. Under the same conditions but with Cu2+ present, the loss rate of PZ is predicted to be 1.23 mole PZ/kg solvent in one year of operation. Inhibitor A was found to be effective at decreasing PZ loss catalyzed by Cu2+. Ethylenediamine, carboxylate ions, and amides were the only identified oxidation products. Total organic carbon analysis and overall mass balances indicate a large concentration of unidentified oxidation products. Advisors/Committee Members: Rochelle, Gary T. (advisor), Maynard, Jennifer A. (committee member), Reible, Danny D. (committee member), Katz, Lynn E. (committee member), Critchfield, James (committee member).

Subjects/Keywords: Degradation; Thermal degradation; Oxidation; Amine degradation; Thermal stability; Piperazine; PZ; CO2 capture; Carbon dioxide capture

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APA (6^th Edition):

Freeman, S. A. (2011). Thermal degradation and oxidation of aqueous piperazine for carbon dioxide capture. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2011-05-3290

Chicago Manual of Style (16^th Edition):

Freeman, Stephanie Anne. “Thermal degradation and oxidation of aqueous piperazine for carbon dioxide capture.” 2011. Doctoral Dissertation, University of Texas – Austin. Accessed March 07, 2021. http://hdl.handle.net/2152/ETD-UT-2011-05-3290.

MLA Handbook (7^th Edition):

Freeman, Stephanie Anne. “Thermal degradation and oxidation of aqueous piperazine for carbon dioxide capture.” 2011. Web. 07 Mar 2021.

Vancouver:

Freeman SA. Thermal degradation and oxidation of aqueous piperazine for carbon dioxide capture. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2011. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/2152/ETD-UT-2011-05-3290.

Council of Science Editors:

Freeman SA. Thermal degradation and oxidation of aqueous piperazine for carbon dioxide capture. [Doctoral Dissertation]. University of Texas – Austin; 2011. Available from: http://hdl.handle.net/2152/ETD-UT-2011-05-3290

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations