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Modelling and sustainability analysis of biorefineries using sugarcane lignocellulose to produce polyethylene, sorbitol, glucaric acid and levulinic acid at existing South African sugar mills
Thesis (PhD)--Stellenbosch University, 2021.
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Stellenbosch : Stellenbosch University
2021
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| _version_ | 1867614079545245696 |
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| access_status_str | Open Access |
| author | Kapanji, Kutemba Kaina |
| author2 | Gorgens, Johann F. |
| author_browse | Gorgens, Johann F. Kapanji, Kutemba Kaina |
| author_facet | Gorgens, Johann F. Kapanji, Kutemba Kaina |
| author_sort | Kapanji, Kutemba Kaina |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/110112 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:46:20.037Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/110112 Modelling and sustainability analysis of biorefineries using sugarcane lignocellulose to produce polyethylene, sorbitol, glucaric acid and levulinic acid at existing South African sugar mills Kapanji, Kutemba Kaina Gorgens, Johann F. Stellenbosch University. Faculty of Engineering. Dept. of Process Engineering. Sustainability -- Evaluation Biomass energy -- Environmental aspects Sugar factories -- South Africa -- Economic aspects Bagasse industry Biorefineries -- Economic aspects Lignocellulose -- Biotechnology UCTD Thesis (PhD)--Stellenbosch University, 2021. ENGLISH ABSTRACT: The sugar industry in South Africa and the region has been plagued by factors including the low international sugar prices, reduced cane yields due to climate change and competition from new market entrants producing sweeteners. Therefore, to remain relevant and sustainable, this industry seeks to generate extra revenue by producing bio-based chemicals and bio-energy from part of the bagasse and brown leaves in biorefinery complexes, alongside sugar products. Using a rapid screening approach, bio-based chemicals polyethylene, sorbitol, glucaric acid and levulinic acid were shortlisted for possible production in such biorefineries (objective one). Conceptual biorefinery process flow diagrams were designed in Aspen Plus® v 8.6 producing the aforementioned chemicals with electricity cogeneration in combined heat and power plants, annexed to a conventional sugar mill (objective two), including a base case scenario that only produced electricity. This was followed by determining the techno-economic viability of the bio-energy self-sufficient biorefineries using developing countries’ economic parameters and a discounted cash flow rate of return methodology on real terms using a 9.7% hurdle rate that reflects South Africa’s and developing countries’ economic conditions (objective three). The internal rate of return (IRR), net present value (NPV) and minimum product selling price (MPSP) were indicators used to determine profitability. The most economically viable scenario coproduced levulinic acid, gamma valerolactone, furfural and electricity (LA-GVL-F-E) and attained a 23% IRR and US$ 253 million NPV at a 9.7% hurdle rate, due to economies of scale benefits and increased profit margins from its multiple chemical products followed by LA-F-E with a 17% IRR and US$ 139 million. At present, most second generation bio-based chemicals cannot compete with first generation or fossil–based counterparts due to the large capital investment costs associated with processing lignocelluloses. A substantial premium is required on second-generation bio-based products if they are to compete with fossil-based or first generation products. In addition to economic viability, the overall sustainability of profitable biorefineries was assessed based on their environmental and social impacts (i.e. job creation) in objective four. For the environmental impact, a “cradle to factory gate” life cycle assessment in SimaPro® was used and the AWARE methodology applied for the water footprint. The most sustainable scenario produced glucaric acid via dilute acid pretreatment (Glucaric.DA) followed by LA-F-E. Objective five was a multi criteria decision assessment (MDCA) on profitable scenarios that ranked and scored the biorefineries based on equal and varied national sustainable (economic, environmental and social) representative weightings. When equal representative weightings of 33.33% were applied to the sustainability indicators, scenario LA-F-E attained the highest aggregate score followed by Glucaric.DA and Sorbitol.DA (chemicals produced via dilute acid pretreatment) and lastly, LA-GVL-F-E. The generated results can inform key sugar industry stakeholders of the most sustainable biorefineries for future feasibility studies. Therefore, potential exists at typical sugar mills for the sustainable valorisation of lignocelluloses for revenue generation and the advancement of a green economy. Future studies should investigate the sustainability of biorefineries utilising first and second generation feedstocks and also valorising part of the lignin to produce high-value chemicals. AFRIKAANSE OPSOMMING: Die suikerindustrie in Suid-Afrika en die streek word deur faktore geteister soos die lae internasionale suikerpryse, verlaagde rietopbrengs as gevolg van klimaatsverandering en kompetisie van nuwe markdeelnemers wat versoeters vervaardig. Daarom, om relevant en volhoubaar te bly, poog die industrie om ekstra inkomste te genereer deur bio-gebaseerde chemikalieë en bio-energie uit ’n gedeelte van die bagasse en bruin blare in bioraffinaderykompleks, saam met suikerprodukte, te produseer. Deur ’n vinnige siftingsbenadering, is bio-gebaseerde chemikalieë poliëtileen, sorbitol, suikersuur en levuliniensuur gekortlys vir moontlike produksie in sulke bioraffinaderye (doelwit 1). Konsepsuele bioraffinaderyprosesvloeidiagramme is ontwerp in Aspen Plus® v 8.6 wat die voorafgenoemde chemikalieë met elektrisiteitkogenerasie produseer in aanlegte wat hitte en krag kombineer, geannekseer aan ’n konvensionele suikermeul (doelwit 2), insluitend ’n basis scenario wat slegs elektrisiteit produseer. Dit is gevolg deur die bepaling van die tegno-ekonomiese uitvoerbaarheid van die bio-energie selfonderhoudende bioraffinaderye deur ontwikkelende lande se ekonomiese parameters te gebruik, en ’n korting op kontantvloeiopbrengsmetodologie op reële terme deur ’n 9.7% versperringskoers te gebruik wat Suid-Afrika en ontwikkelende lande se ekonomiese kondisies reflekteer (doelwit 3). Die interne opbrengskoers (IRR), netto huidige waarde (NPV) en minimum produkverkoopsprys (MPSP) was indikators wat gebruik is om winsgewendheid te bepaal. Die mees ekonomies uitvoerbare scenario het levuliniensuur, gamma valerolaktoon, furfuraal en elektrisiteit (LA-GVL-F-E) koproduseer en het ’n 23% IRR en US$253 miljoen NPV gehad by ’n 9.7% versperringskoers, as gevolg van skaalbesparingsvoordele en verhoogde winsmarge van sy veelvoudige chemiese produkte, gevolg deur LA-F-E met ’n 17% IRR en US$139 miljoen. Tans kan meeste tweede-generasie bio-gebaseerde chemikalieë nie met eerste generasie of fossiel-gebaseerde teenbeelde kompeteer nie as gevolg van die groot kapitaalbeleggingkostes geassosieer met prosessering van lignosellulose. ’n Aansienlike premie word vereis op tweede-generasie bio-gebaseerde produkte as hulle met fossiel-gebaseerde of eerste-generasie produkte wil kompeteer. Saam met ekonomiese uitvoerbaarheid, is die algehele volhoubaarheid van winsgewende bioraffinaderye geassesseer gebaseer op hul omgewings- en sosiale impak (i.e. werkskepping) in doelwit 4. Vir die omgewingsimpak is ’n lewenssiklusanalise van die “begin tot fabriekshek” in SimaPro® gebruik en die AWARE-metodologie toegepas vir die watervoetspoor. Die mees volhoubare scenario het suikersuur via verdunde suur voorbehandeling (Glucaric.DA) produseer, gevolg deur LA-F-E. Doelwit vyf was ’n multikriteriabesluitassessering (MDCA) op winsgewende scenario’s wat bioraffinaderye rangskik en punte gee gebaseer op gelyke en gevarieerde nasionale volhoubaarheid (ekonomies, omgewing, en sosiaal) verteenwoordigende gewigstoekennings. Toe gelyke verteenwoordigende gewigstoekennings van 33.33% toegepas is op die volhoubaarheidsindikators, het scenario LA-F-E die hoogste aggregaattelling behaal, gevolg deur Glucaric.DA en Sorbitol.DA (chemikalieë geproduseer via verdunde suur voorbehandeling), en laaste, LA-GVL-F-E. Die gegenereerde resultate kan sleutel suikerindustriebelanghebbers van die mees volhoubare bioraffinaderye inlig vir toekomstige uitvoerbaarheidstudies. Potensiaal bestaan daarom by tipiese suikermeule vir die volhoubare valorisasie van lignosellulose vir inkomstegenerasie en die bevordering van ’n groen ekonomie. Toekomstige studies moet die volhoubaarheid van bioraffinaderye wat eerste- en tweede-generasie toevoermateriale gebruik, ondersoek, en ook die valorisering van ʼn gedeelte van die lignien om hoë waarde chemikalieë te produseer. The financial assistance of the National Research Foundation (NRF) towards this research is hereby acknowledged. Opinions expressed and conclusions arrived at, are those of the author and are not necessarily attributed to the NRF. Doctoral 2021-03-08T11:22:18Z 2021-04-21T14:40:55Z 2021-03-08T11:22:18Z 2021-04-21T14:40:55Z 2021-03 Thesis http://hdl.handle.net/10019.1/110112 en_ZA Stellenbosch University xxiv, 361 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Sustainability -- Evaluation Biomass energy -- Environmental aspects Sugar factories -- South Africa -- Economic aspects Bagasse industry Biorefineries -- Economic aspects Lignocellulose -- Biotechnology UCTD Kapanji, Kutemba Kaina Modelling and sustainability analysis of biorefineries using sugarcane lignocellulose to produce polyethylene, sorbitol, glucaric acid and levulinic acid at existing South African sugar mills |
| title | Modelling and sustainability analysis of biorefineries using sugarcane lignocellulose to produce polyethylene, sorbitol, glucaric acid and levulinic acid at existing South African sugar mills |
| title_full | Modelling and sustainability analysis of biorefineries using sugarcane lignocellulose to produce polyethylene, sorbitol, glucaric acid and levulinic acid at existing South African sugar mills |
| title_fullStr | Modelling and sustainability analysis of biorefineries using sugarcane lignocellulose to produce polyethylene, sorbitol, glucaric acid and levulinic acid at existing South African sugar mills |
| title_full_unstemmed | Modelling and sustainability analysis of biorefineries using sugarcane lignocellulose to produce polyethylene, sorbitol, glucaric acid and levulinic acid at existing South African sugar mills |
| title_short | Modelling and sustainability analysis of biorefineries using sugarcane lignocellulose to produce polyethylene, sorbitol, glucaric acid and levulinic acid at existing South African sugar mills |
| title_sort | modelling and sustainability analysis of biorefineries using sugarcane lignocellulose to produce polyethylene sorbitol glucaric acid and levulinic acid at existing south african sugar mills |
| topic | Sustainability -- Evaluation Biomass energy -- Environmental aspects Sugar factories -- South Africa -- Economic aspects Bagasse industry Biorefineries -- Economic aspects Lignocellulose -- Biotechnology UCTD |
| url | http://hdl.handle.net/10019.1/110112 |
| work_keys_str_mv | AT kapanjikutembakaina modellingandsustainabilityanalysisofbiorefineriesusingsugarcanelignocellulosetoproducepolyethylenesorbitolglucaricacidandlevulinicacidatexistingsouthafricansugarmills |