subject:(Fouling test)

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University of Cape Town

1. Hallatt, Nicolaas. The development of a test rig to determine fouling factors of feedwater heaters.

Degree: MSc, Mechanical Engineering, 2019, University of Cape Town

► Feed water heaters are large shell and tube heat exchangers. They from part of the Rankine cycle used in coal fired power plants with the… (more)

▼ Feed water heaters are large shell and tube heat exchangers. They from part of the Rankine cycle used in coal fired power plants with the main purpose being the improvement of the overall cycle efficiency. Like most heat exchangers, feed water heaters suffer from fouling. Fouling is defined as “any undesirable deposit on heat exchanger surfaces that increases resistance to heat transmission”. In the design of heat exchangers, fouling is accommodated by adding additional surface area to the heat exchanger. The amount of additional area is determined by the use of fouling factors. Although this is the only wide-spread method accepted in industry, the fouling factors in use are outdated, generally considered conservative and lead to oversized heat exchangers. The purpose of this study was to design and build a test rig that can accurately measure fouling factors of feed water heater tubes that has been in service for a full life cycle. A comprehensive literature study was performed to decide on the most effective test method, as well as the required instrument type and accuracy. The best method was found to be where the overall heat transfer coefficient for a fouled tube, outside cleaned tube (half clean) and clean tube was measured. The measured values are then converted to the internal, external and overall fouling factors. Validation test were done on the test rig. These included energy balance tests, theoretical comparison tests and repeatability tests. The results of all tests were acceptable and within measurement uncertainty limits. Five sample test tubes, obtained from a 30 year old LP heater at an Eskom power station, were tested. The results indicated that the average measured fouling factors were less than 20% of the commonly used HEI fouling factors. This is significantly lower and confirms that the fouling factors in use for this specific case are conservative. The test rig proved to be accurate and effective in measuring the fouling factors. Although the tests shows promising results, the small amount of tubes tested from only one heat exchanger are not sufficient to make meaningful conclusions. The test rig is now ready for a future study where a large sample of tubes can be tested. Advisors/Committee Members: Fuls, Wim (advisor).

Subjects/Keywords: Feedwater Heater; Fouling Factors; Test Rig

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APA (6^th Edition):

Hallatt, N. (2019). The development of a test rig to determine fouling factors of feedwater heaters. (Masters Thesis). University of Cape Town. Retrieved from http://hdl.handle.net/11427/31774

Chicago Manual of Style (16^th Edition):

Hallatt, Nicolaas. “The development of a test rig to determine fouling factors of feedwater heaters.” 2019. Masters Thesis, University of Cape Town. Accessed February 26, 2021. http://hdl.handle.net/11427/31774.

MLA Handbook (7^th Edition):

Hallatt, Nicolaas. “The development of a test rig to determine fouling factors of feedwater heaters.” 2019. Web. 26 Feb 2021.

Vancouver:

Hallatt N. The development of a test rig to determine fouling factors of feedwater heaters. [Internet] [Masters thesis]. University of Cape Town; 2019. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/11427/31774.

Council of Science Editors:

Hallatt N. The development of a test rig to determine fouling factors of feedwater heaters. [Masters Thesis]. University of Cape Town; 2019. Available from: http://hdl.handle.net/11427/31774

University of Illinois – Urbana-Champaign

2. Qian, Yu. Integrated computational and experimental framework for the assessment of railroad ballast life-cycle behavior.

Degree: PhD, 0106, 2015, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/72751

► Ballast, typically comprising large sized aggregate particles with uniform gradation, is an essential layer in the railroad track substructure. Functions of ballast include facilitating load… (more)

▼ Ballast, typically comprising large sized aggregate particles with uniform gradation, is an essential layer in the railroad track substructure. Functions of ballast include facilitating load distribution and drainage, maintaining track geometry and track stability, and providing track resilience and noise absorption. Throughout its service life, ballast goes through changes in gradation and aggregate particle shape properties. These changes affect the particulate nature of ballast layer behavior, which has not been thoroughly understood from laboratory experiments and field performance. Moreover, numerical simulations that treat ballast as a continuum layer may often fail to address individual particle interactions at the micro-scale, which is a key perspective in modeling more realistically the behavior of any aggregate layer assembly. The main focus in this research effort has been to develop an integrated computational-experimental framework to evaluate ballast life-cycle behavior. Laboratory experiments and numerical simulations based on the Discrete Element Method (DEM) were performed to better understand micro-mechanical interactions affecting complex ballast assembly behavior and to provide quantitative evaluations of field response and performance under dynamic train loading. Starting from aggregate particle scale, grain size distributions and particle morphological properties of clean and fouled ballast materials were analyzed in the laboratory in order to provide input properties for the DEM numerical simulations. Moving to the laboratory scale, large-scale triaxial tests were performed in the laboratory under controlled monotonic and repeated loading conditions for shear strength and permanent deformation characteristics, respectively. The experimental studies indicated that the shearing rate had no significant influence on the results of the ballast triaxial tests. Compared to clean ballast, fouled ballast samples in dry condition had higher permanent deformation under repeated loading due to particle degradation but not necessarily lower strength than clean ballast. The laboratory experiments were simulated using the DEM platform, which integrated aggregate image analysis technology into numerical modeling with the ability to generate particles in the DEM simulations for the same grain size distributions and morphological properties of ballast particles used in the laboratory tests. The DEM simulations of shear strength and permanent deformation tests could capture complex ballast behavior reasonably accurately. With the use of a newly introduced “incremental displacement” shearing method, numerical simulations could be completed with less iteration or computational expense. Using the integrated computational-experimental framework, effects of geogrid reinforcement and presence of moisture on ballast at different stages of its life-cycle have also been investigated. Furthermore, full validation of the framework approach was accomplished through field testing efforts; ballast settlement trends computed… Advisors/Committee Members: Tutumluer, Erol (advisor), Tutumluer, Erol (Committee Chair), Hashash, Youssef M. (committee member), Ghaboussi, Jamshid (committee member), Barkan, Christopher P.L. (committee member), Buttlar, William G. (committee member).

Subjects/Keywords: ballast; discrete element modeling; triaxial test; filed test; strength; permanent deformation; fouling; degradation

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APA (6^th Edition):

Qian, Y. (2015). Integrated computational and experimental framework for the assessment of railroad ballast life-cycle behavior. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/72751

Chicago Manual of Style (16^th Edition):

Qian, Yu. “Integrated computational and experimental framework for the assessment of railroad ballast life-cycle behavior.” 2015. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed February 26, 2021. http://hdl.handle.net/2142/72751.

MLA Handbook (7^th Edition):

Qian, Yu. “Integrated computational and experimental framework for the assessment of railroad ballast life-cycle behavior.” 2015. Web. 26 Feb 2021.

Vancouver:

Qian Y. Integrated computational and experimental framework for the assessment of railroad ballast life-cycle behavior. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2015. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/2142/72751.

Council of Science Editors:

Qian Y. Integrated computational and experimental framework for the assessment of railroad ballast life-cycle behavior. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/72751

McMaster University

3. Kazemi, Amir Sadegh. Development of stirred well filtration as a high-throughput technique for downstream bioprocessing.

Degree: MASc, 2014, McMaster University

URL: http://hdl.handle.net/11375/16153

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Micro-scale processing (MSP) techniques are miniaturized version of upstream and downstream conventional unit operations that are designed to accelerate the pace of bioprocess design and… (more)

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Micro-scale processing (MSP) techniques are miniaturized version of upstream and downstream conventional unit operations that are designed to accelerate the pace of bioprocess design and development. Previous ‘dead end’ filtration studies have demonstrated the usefulness of this concept for membrane filtration processes. However, these experiments were performed without stirring which is the most common strategy to control the effects of concentration polarization and fouling on filtration performance. In this work, the pressure-driven stirred conditions of a conventional stirred-cell module were integrated with a 96-well filter plate to develop a high throughput technique called ‘stirred-well filtration’ (SWF). The design allowed for up to eight constant flux filtration experiments to be conducted at once using a multi-rack programmable syringe pump and a magnetic lateral tumble stirrer. An array of pressure transducers was used to monitor the transmembrane pressure (TMP) in each well. The protein sieving behavior and fouling propensity of Omega™ ultrafiltration membranes were assessed via a combination of hydraulic permeability measurements and protein sieving tests in constant filtrate flux mode. The TMP profile during filtration of bovine serum albumin (BSA) solution was strongly dependent on the stirring conditions – for example the maximum TMP in the stirred wells were an average of 7.5, 3.8, and 2.6 times lower than those in the unstirred wells at filtrate fluxes of 12, 36, and 60 LMH (5, 15, and 25 μL/min) respectively. The consistency of the data across different wells for the same stirring condition was very good. To demonstrate the effectiveness of the SWF technique, the eight tests for a simple 2² factorial design-of-experiments (DOE) test with duplicates was run to evaluate the effect of solution pH and salt concentration on protein filtration. The combination of SWF with statistical methods such as DOE is shown to be an effective strategy for high-throughput optimization of membrane filtration processes.

Dissertation

Master of Applied Science (MASc)

Advisors/Committee Members: Latulippe, David, Chemical Engineering.

Subjects/Keywords: Microscale processing; High-throughput testing; Downstream bioprocessing; Stirred well filtration (SWF); BSA filtration; Micromixing; Fouling test; Omega™ membrane

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APA (6^th Edition):

Kazemi, A. S. (2014). Development of stirred well filtration as a high-throughput technique for downstream bioprocessing. (Masters Thesis). McMaster University. Retrieved from http://hdl.handle.net/11375/16153

Chicago Manual of Style (16^th Edition):

Kazemi, Amir Sadegh. “Development of stirred well filtration as a high-throughput technique for downstream bioprocessing.” 2014. Masters Thesis, McMaster University. Accessed February 26, 2021. http://hdl.handle.net/11375/16153.

MLA Handbook (7^th Edition):

Kazemi, Amir Sadegh. “Development of stirred well filtration as a high-throughput technique for downstream bioprocessing.” 2014. Web. 26 Feb 2021.

Vancouver:

Kazemi AS. Development of stirred well filtration as a high-throughput technique for downstream bioprocessing. [Internet] [Masters thesis]. McMaster University; 2014. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/11375/16153.

Council of Science Editors:

Kazemi AS. Development of stirred well filtration as a high-throughput technique for downstream bioprocessing. [Masters Thesis]. McMaster University; 2014. Available from: http://hdl.handle.net/11375/16153

The Ohio State University

4. Plewacki, Nicholas. Modeling High Temperature Deposition in Gas Turbines.

Degree: MS, Aero/Astro Engineering, 2020, The Ohio State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1587714424017527

► This thesis covers the intensive research effort to elucidate the role of elevated temperature in deposition. Several experimental campaigns were conducted in this pursuit. The… (more)

▼ This thesis covers the intensive research effort to elucidate the role of elevated temperature in deposition. Several experimental campaigns were conducted in this pursuit. The testing explored high temperature deposition with 0-10 micron Arizona Road Dust (ARD) with the intent of creating a yield strength model that included temperature effects and could be incorporated into the existing OSU deposition model.Experimental work was first conducted in the impulse kiln facility where small amounts of the test dust were placed on ceramic targets and rapidly exposed to temperatures between 1200K and 1500K. Trends in the packing factor confirmed the existence of two threshold values (1350K and 1425K) that could be linked to strength characteristics of the dust when exposed to high temperatures. Using the information obtained from the kiln experiments, HTDF testing was conducted between 1325K and 1525K. Exit temperatures were set at 25K intervals in this region with a constant jet velocity of 150 m/s. The capture efficiency data showed this trend with temperature and indicated a softening temperature and melting temperature of 1362K and 1512K respectively. With these critical values in hand, the Ohio State University Molten Model was created to modify yield strength with particle velocity and temperature. The model was tested using CFD and showed a good capability for capturing particle temperature effects in deposition from an impinging particle-laden jet.A subsequent test campaign was conducted to explore the effect of varying surface temperature on deposition. Hastelloy coupons with Thermal Barrier Coatings (TBCs) were subjected to a constant jet at 1600K jet and 200 m/s while being cooled via a backside impingement jet. Surface temperatures between 1455K and 1125K were impacted with 0-10 micron ARD while an IR camera monitored the surface. Coupons with higher coolant flowrates (lower surface temperature) saw significantly lower deposition rates than the higher surface temperatures. CFD simulations using the newly vetted OSU Molten Model were not able to account for the strong decrease in deposition with boundary layer cooling. Therefore, it was posited that the model should eventually incorporate both particle and surface temperatures in its formulation. Advisors/Committee Members: Bons, Jeffrey (Advisor).

Subjects/Keywords: Aerospace Engineering; depostion; gas turbine; gas turbine engine; turbomachinery; fouling; particle; particle impact; particle deposition; melting; experiment; combustion; multiphase flow; test dust; dust; gas turbine deposition; engine efficiency; propulsion; jet engine

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

APA (6^th Edition):

Plewacki, N. (2020). Modeling High Temperature Deposition in Gas Turbines. (Masters Thesis). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1587714424017527

Chicago Manual of Style (16^th Edition):

Plewacki, Nicholas. “Modeling High Temperature Deposition in Gas Turbines.” 2020. Masters Thesis, The Ohio State University. Accessed February 26, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587714424017527.

MLA Handbook (7^th Edition):

Plewacki, Nicholas. “Modeling High Temperature Deposition in Gas Turbines.” 2020. Web. 26 Feb 2021.

Vancouver:

Plewacki N. Modeling High Temperature Deposition in Gas Turbines. [Internet] [Masters thesis]. The Ohio State University; 2020. [cited 2021 Feb 26]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1587714424017527.

Council of Science Editors:

Plewacki N. Modeling High Temperature Deposition in Gas Turbines. [Masters Thesis]. The Ohio State University; 2020. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1587714424017527

5. Kazemi, Amir Sadegh. Development of High-throughput Membrane Filtration Techniques for Biological and Environmental Applications.

Degree: PhD, 2018, McMaster University

URL: http://hdl.handle.net/11375/23404

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Membrane filtration processes are widely utilized across different industrial sectors for biological and environmental separations. Examples of the former are sterile filtration and protein fractionation via microfiltration (MF) and ultrafiltration (UF) while drinking water treatment, tertiary treatment of wastewater, water reuse and desalination via MF, UF, nanofiltration (NF) and reverse-osmosis (RO) are examples of the latter. A common misconception is that the performance of membrane separation is solely dependent on the membrane pore size, whereas a multitude of parameters including solution conditions, solute concentration, presence of specific ions, hydrodynamic conditions, membrane structure and surface properties can significantly influence the separation performance and the membrane’s fouling propensity. The conventional approach for studying filtration performance is to use a single lab- or pilot-scale module and perform numerous experiments in a sequential manner which is both time-consuming and requires large amounts of material. Alternatively, high-throughput (HT) techniques, defined as the miniaturized version of conventional unit operations which allow for multiple experiments to be run in parallel and require a small amount of sample, can be employed. There is a growing interest in the use of HT techniques to speed up the testing and optimization of membrane-based separations. In this work, different HT screening approaches are developed and utilized for the evaluation and optimization of filtration performance using flat-sheet and hollow-fiber (HF) membranes used in biological and environmental separations. The effects of various process factors were evaluated on the separation of different biomolecules by combining a HT filtration method using flat-sheet UF membranes and design-of-experiments methods. Additionally, a novel HT platform was introduced for multi-modal (constant transmembrane pressure vs. constant flux) testing of flat-sheet membranes used in bio-separations. Furthermore, the first-ever HT modules for parallel testing of HF membranes were developed for rapid fouling tests as well as extended filtration evaluation experiments. The usefulness of the modules was demonstrated by evaluating the filtration performance of different foulants under various operating conditions as well as running surface modification experiments. The techniques described herein can be employed for rapid determination of the optimal combination of conditions that result in the best filtration performance for different membrane separation applications and thus eliminate the need to perform numerous conventional lab-scale tests. Overall, more than 250 filtration tests and 350 hydraulic permeability measurements were performed and analyzed using the HT platforms developed in this thesis.

Thesis

Doctor of Philosophy (PhD)

Membrane filtration is widely used as a key separation process in different industries. For example, microfiltration (MF) and ultrafiltration (UF) are used for sterilization and…

Advisors/Committee Members: Latulippe, David, Chemical Engineering.

Subjects/Keywords: Membrane filtration; Ultrafiltration; Downstream bio-processing; High-throughput (HT) testing; Wastewater treatment; Hollow-fiber membranes; Humic acids; High-throughput filtration; Design-of-experiments (DOE); Process optimization; Microscale filtration; Microfluidic flow control system; Stirred well filtration; SWF; High-throughput hollow-fiber module; HT-HF; Constant TMP; Constant flux; Multi-modal filtration; Bioseparation; MMFC; Microscale parallel-structured, cross-flow filtration; MS-PS-CFF; PEG; Dextran; FITC-Dextran; BSA; DNA; IgG; α-lactalbumin; Biomolecule separation; Module hydrodynamics; Concentration polarization; Membrane fouling; Micromixing; Omega™ membrane; Microscale processing; Fouling test; PVDF membrane; Surface modification; Polydopamine; Membrane cleaning; Membrane backwashing; Sodium alginate; Polyethersulfone; PES; Hydraulic permeability; Membrane permeability; ZeeWeed® membrane; Filtration ionic strength; Filtration pH; Solution conditions; Water treatment; Environmental separations; Biological separations

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

APA (6^th Edition):

Kazemi, A. S. (2018). Development of High-throughput Membrane Filtration Techniques for Biological and Environmental Applications. (Doctoral Dissertation). McMaster University. Retrieved from http://hdl.handle.net/11375/23404

Chicago Manual of Style (16^th Edition):

Kazemi, Amir Sadegh. “Development of High-throughput Membrane Filtration Techniques for Biological and Environmental Applications.” 2018. Doctoral Dissertation, McMaster University. Accessed February 26, 2021. http://hdl.handle.net/11375/23404.

MLA Handbook (7^th Edition):

Kazemi, Amir Sadegh. “Development of High-throughput Membrane Filtration Techniques for Biological and Environmental Applications.” 2018. Web. 26 Feb 2021.

Vancouver:

Kazemi AS. Development of High-throughput Membrane Filtration Techniques for Biological and Environmental Applications. [Internet] [Doctoral dissertation]. McMaster University; 2018. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/11375/23404.

Council of Science Editors:

Kazemi AS. Development of High-throughput Membrane Filtration Techniques for Biological and Environmental Applications. [Doctoral Dissertation]. McMaster University; 2018. Available from: http://hdl.handle.net/11375/23404

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