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University of Oulu

1. Upola, H. (Heikki). Disintegration of packaging material:an experimental study of approaches to lower energy consumption.

Degree: 2017, University of Oulu

Abstract The old corrugated container (OCC) recycling process produces pulp suspension from recovered packaging material with sufficient strength and cleanliness to meet regulatory requirements for produced packaging material. Pulping is the first unit operation in the OCC recycling process and the most energy-intensive unit operation, accounting for 20–30% of the total energy used in the process, if dispersion is not used. From the viewpoint of improving the energy efficiency of the OCC recycling process, the pulping stage is an important research target. The approach of this thesis work was to experimentally study practical possibilities to decrease the energy requirements of the OCC pulping process by understanding disintegration mechanisms and pulping fundamentals. The pulping process was conceptually divided into three separate phases: wetting, bulk disintegration, and residual disintegration. The aim was to elucidate the effect of each phase on disintegration kinetics and specific energy consumption of pulping, and to discuss how those phases could be intensified to minimize energy consumption. The results suggest that forced wetting of OCC material by mechanical pressing increases the disintegration rate owing to thorough impregnation of water into the OCC material, which efficiently reduces the material’s wet strength by cutting hydrogen bonds. The method can potentially reduce the energy requirement of the pulping process by about 30%. Bulk disintegration by falling the material in high-consistency drum pulping was emulated in a specially designed device. The results reveal that the energy needed for material disintegration depends significantly on the material’s wet strength. Pulping energy consumption can be lowered in the residual disintegration phase by separating the easily disintegrated weaker materials in an early stage from the drum and continuing pulping of the remaining non-disintegrated material (Fractional pulping). This setup led to estimated energy savings of around 20%. During the thesis work, the authors developed an analysis device that photographs flakes separated from the pulp and determines flake size distribution by image analysis. The device revealed the difference between the low- and medium-consistency OCC pulping mechanisms.

Tiivistelmä Pahvin kierrätysprosessissa kerätyistä pakkausmateriaaleista valmistetaan uusiomassaa, joka käytetään uuden pahvin valmistukseen. Kierrätysprosessin ensimmäinen yksikköoperaatio on pulpperointi eli pahviraaka-aineen kuiduttaminen sulpuksi. Pulpperointi on usein koko kierrätysprosessin energiankulutukseltaan suurin yksikköprosessi, joka voi viedä jopa 20 – 30 % koko prosessin energiankulutuksesta. Tämän vuoksi pulpperoinnin energiankulutuksen pienentämiseen tähtäävä tutkimus on erittäin tärkeää. Työn tarkoituksena oli tutkia kokeellisin menetelmin mahdollisuuksia vähentää pulpperoinnin energiankulutusta. Tavoitteena oli saada ymmärrystä pulpperoinnin hajotusmekanismeista ja pulpperointiin vaikuttavista tekijöistä. Tässä työssä pulpperointi…

Advisors/Committee Members: Illikainen, M. (Mirja), Ämmälä, A. (Ari).

Subjects/Keywords: OCC; Pre-wetting; corrugated container; defibering; disintegration; pulping; recycling; repulping; esivettyminen; kierrätys; kuidutus; pahvi; pakkausmateriaali; pulpperointi; rumpupulpperi

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

APA (6th Edition):

Upola, H. (. (2017). Disintegration of packaging material:an experimental study of approaches to lower energy consumption. (Doctoral Dissertation). University of Oulu. Retrieved from http://urn.fi/urn:isbn:9789526214788

Chicago Manual of Style (16th Edition):

Upola, H (Heikki). “Disintegration of packaging material:an experimental study of approaches to lower energy consumption.” 2017. Doctoral Dissertation, University of Oulu. Accessed August 23, 2017. http://urn.fi/urn:isbn:9789526214788.

MLA Handbook (7th Edition):

Upola, H (Heikki). “Disintegration of packaging material:an experimental study of approaches to lower energy consumption.” 2017. Web. 23 Aug 2017.

Vancouver:

Upola H(. Disintegration of packaging material:an experimental study of approaches to lower energy consumption. [Internet] [Doctoral dissertation]. University of Oulu; 2017. [cited 2017 Aug 23]. Available from: http://urn.fi/urn:isbn:9789526214788.

Council of Science Editors:

Upola H(. Disintegration of packaging material:an experimental study of approaches to lower energy consumption. [Doctoral Dissertation]. University of Oulu; 2017. Available from: http://urn.fi/urn:isbn:9789526214788

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