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Techno-economic analysis of integrated sugarcane biorefinery scenarios for the production of 2,3-butanediol, 1,3-butadiene, polyhydroxybutyrate (PHB) or citric acid
Thesis (MEng)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867613805667680256 |
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| access_status_str | Open Access |
| author | Gouws, Mirelle René |
| author2 | Görgens, Johann Ferdinand |
| author_browse | Gouws, Mirelle René Görgens, Johann Ferdinand |
| author_facet | Görgens, Johann Ferdinand Gouws, Mirelle René |
| author_sort | Gouws, Mirelle René |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/127275 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:41:59.323Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/127275 Techno-economic analysis of integrated sugarcane biorefinery scenarios for the production of 2,3-butanediol, 1,3-butadiene, polyhydroxybutyrate (PHB) or citric acid Gouws, Mirelle René Görgens, Johann Ferdinand Dogbe, Eunice Sefakor Stellenbosch University. Faculty of Engineering. Dept. of Process Engineering. Sugar factories – Economic aspects -- South Africa Citric acid -- South Africa Biorefineries -- South Africa Thesis (MEng)--Stellenbosch University, 2023. ENGLISH ABSTRACT: To prevent the closures of South African sugar mills currently experiencing economic strain, biorefineries annexed to existing sugar mills - utilizing residues and/or by-products from the mill - for profitable biochemical and/or biofuel production, have been suggested. Residues and/or by-products readily available at a sugar mill include sugarcane molasses, first-generation (1G) feedstock, and sugarcane bagasse and brown leaves from harvesting residues, second generation (2G) feedstock. The study considered the economic feasibility of individually producing either 2,3-butanediol (2,3-BDO), 1,3-butadiene (1,3-BD), polyhydroxybutyrate (PHB) or citric acid at a biorefinery annexed to an existing sugar mill. Two biorefinery scenarios were developed for 2,3-BDO, PHB and citric acid, utilizing either 1G or integrated 1G2G feedstock. For 1,3-BD however, four scenarios were developed, where two scenarios produce 1,3-BD with 2,3-BDO as intermediate product and two produce 1,3-BD with ethanol as intermediate product. The study involved process development based on literature data, simulation of the production processes using Aspen Plus® software, conducting techno-economic analyses to determine the primary economic indicator, minimum selling price (MSP), and conducting sensitivity analyses to assess which factors had the largest impact on the MSP of each scenario. Finally, the greenhouse gas emissions (GHG) of each scenario was determined using the RSB GHG Calculator Tool. The MSPs determined for 2,3-BDO, 1,3-BD, PHB and citric acid were 1.91 and 2.28 $/kg; 4.08, 4.55, 5.71 and 5.72 $/kg; 6.81 and 7.23 $/kg; and 2.44 and 2.60 $/kg, respectively. The 2,3-BDO and PHB biorefinery scenarios were all deemed profitable with regards to the respective market prices of 2.63 $/kg and 7.6 $/kg. The 1,3-BD and citric acid scenarios were all deemed unprofitable, with market prices of 1.05 $/kg and 0.8 $/kg. The difference in MSPs can overall be attributed to the yields of the various processes, although, the yield is not the only decisive factor. Citric acid, with an exceptional overall yield, had a higher MSP compared to 2,3-BDO, with a lower overall yield, due to the high capital cost associated with aerobic fermentation of citric acid versus microaerobic fermentation of 2,3-BDO. Producing 1,3-BD with 2,3-BDO as intermediate product was more economical with MSPs of 4.08 and 4.55 $/kg compared to producing 1,3-BD with ethanol as intermediate with MSPs of 5.71 and 5.72 $/kg. This was mainly attributed to low catalytic selectivities and conversions of the latter as well as the high capital costs associated with the two-step catalytic upgrading of ethanol to 1,3-BD. Furthermore, utilizing 1G feedstock at a biorefinery proved to be more economical compared to utilizing 1G2G feedstock. The inferior economics of a 1G2G biorefinery can be attributed to the significant utility and capital cost contributions associated with 2G feedstock processing. Specifically the high capital cost of enzymatic hydrolysis equipment and the high energy consumption associated with the concentration of the hemicellulose hydrolysate prior to fermentation. The PHB scenarios were the only scenarios with notable GHG emissions. The low utility requirements of these scenarios meant that most of the biogas produced in the wastewater treatment plant was flared, releasing large quantities of CO2 into the atmosphere. AFRIKAANS OPSOMMING: Om die sluiting van Suid-Afrikaanse suikermeulens, wat tans ekonomiese druk ervaar, te voorkom, is bioraffinaderye wat aan bestaande suikermeulens geannekseer is – wat residu en/of neweprodukte vanaf die meule benut – voorgestel vir winsgewende biochemiese en/of biobrandstandstof produksie. Residu en/of neweprodukte wat geredelik vanaf ‘n suikermeul beskikbaar is, sluit in suikerrietmolasse, eerstegenerasie (1G) grondstof, en suikerrietbagasse en bruin blare vanaf oesreste, tweedegenerasie (2G) grondstof. Die studie het die ekonomiese uitvoerbaarheid oorweeg om individueel óf 2,3-butaandiol (2,3-BDO), 1,3- butadieen (1,3-BD), polihidroksiebutiraat (PHB) óf sitroensuur te produseer by ‘n bioraffinadery wat aan ‘n bestaande suikermeul geannekseer is. Twee bioraffinadery-scenario’s is ontwikkel vir 2,3-BDO, PHB en sitroensuur, met die gebruik van óf 1G grondstof óf geïntegreerde 1G2G grondstof. Vir 1,3-BD is daar egter vier scenario’s ontwikkel, waar twee scenario’s 1,3-BD produseer met 2,3-BDO as tussenproduk en twee scenario’s 1,3-BD produseer met etanol as tussenproduk. Die studie behels prosesontwikkeling gebaseer op literatuurdata, simulasie van die produksieprosesse deur gebruik te maak van Aspen Plus® sagteware, die uitvoer van tegno-ekonomiese analises om die primêre ekonomiese aanwyser, die minimum verkoopprys (MSP), te bepaal, en die uitvoer van sensitiwiteitsanalises om te bepaal watter faktore die grootste impak op die MSP van elke scenario het. Laastens is die kweekhuisgasvrystellings (GHG) van elke scenario bepaal met behulp van die RSB GHG berekeningsgereedskap. Die MSP’s wat vir 2,3-BDO, 1,3-BD, PHB en sitroensuur bepaal was, is 1.91 en 2.28 $/kg; 4.08, 4.55, 5.71 en 5.72 $/kg; 6.81 en 7.23 $/kg; en 2.44 en 2.60 $/kg, onderskeidelik. Die 2,3-BDO en PHB bioraffinadery scenario’s word almal as winsgewend beskou met betrekking tot hulle onderskeie markpryse van 2.63 $/kg en 7.6 $/kg. Die 1,3-BD en sitroensuur scenario’s word almal as onwinsgewend beskou, met markpryse van 1.05 $/kg and 0.8 $/kg. Die verskil in MSP’s kan oor die algemeen toegeskryf word aan die opbrengste van die verskillende prosesse, alhoewel die opbrengs nie die enigste deurslaggewende faktor is nie. Sitroensuur, met ‘n uitsonderlike algehele opbrengs, het ‘n hoër MSP in vergelyking met 2,3-BDO, met ‘n laer algehele opbrengs, as gevolg van die hoër kapitaalkoste wat met aërobiese fermentasie van sitroensuur geassosieer word in vergelyking met die mikroaerobiese fermentasie van 2,3-BDO. Die vervaardiging van 1,3-BD met 2,3-BDO as tussenproduk is meer ekonomies met MSP’s van 4.08 en 4.55 $/kg in vergelyking met die vervaardiging van 1,3-BD met etanol as tussenproduk met MSP’s van 5.71 and 5.72 $/kg. Dit kan hoofsaaklik toegeskryf word aan die lae katalitiese selektiwiteite en omskakelings van die laasgenoemde sowel as die hoë kapitaalkoste wat met twee-stap katalitiese opgradering van ethanol na 1,3-BD geassosieer word. Verder was die gebruik van 1G grondstof by ‘n bioraffinadery meer ekonomies in vergelyking met die gebruik van 1G2G grondstof. Die substandaarde ekonomiese resultate van ‘n 1G2G bioraffinadery kan toegeskryf word aan die aansienlike energie- en kapitaalkostes wat met die verwerking van 2G grondstof geassosieer word. Spesifiek die hoë kapitaalkoste van ensiematiese hidrolise-toerusting en die hoë energieverbruik wat met die konsentrasie van die hemisellulose hidrolisaat voor fermentasie geassosieer word. Die PHB scenario’s was die enigste scenario’s met noemenswaardige GHG uitlaatings. Die lae energie- en hitteverbruik van dié scenario’s het beteken dat meeste van die biogas wat in die afvalwatersuiweringsaanleg vervaardig is, opgevlam word, wat groot hoeveelhede CO2 in die atmosfeer vrystel. Masters 2023-03-03T12:02:07Z 2023-05-18T07:13:30Z 2023-03-03T12:02:07Z 2023-05-18T07:13:30Z 2023-03 Thesis http://hdl.handle.net/10019.1/127275 en_ZA en_ZA Stellenbosch University Ix, 147, xxxvii pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Sugar factories – Economic aspects -- South Africa Citric acid -- South Africa Biorefineries -- South Africa Gouws, Mirelle René Techno-economic analysis of integrated sugarcane biorefinery scenarios for the production of 2,3-butanediol, 1,3-butadiene, polyhydroxybutyrate (PHB) or citric acid |
| title | Techno-economic analysis of integrated sugarcane biorefinery scenarios for the production of 2,3-butanediol, 1,3-butadiene, polyhydroxybutyrate (PHB) or citric acid |
| title_full | Techno-economic analysis of integrated sugarcane biorefinery scenarios for the production of 2,3-butanediol, 1,3-butadiene, polyhydroxybutyrate (PHB) or citric acid |
| title_fullStr | Techno-economic analysis of integrated sugarcane biorefinery scenarios for the production of 2,3-butanediol, 1,3-butadiene, polyhydroxybutyrate (PHB) or citric acid |
| title_full_unstemmed | Techno-economic analysis of integrated sugarcane biorefinery scenarios for the production of 2,3-butanediol, 1,3-butadiene, polyhydroxybutyrate (PHB) or citric acid |
| title_short | Techno-economic analysis of integrated sugarcane biorefinery scenarios for the production of 2,3-butanediol, 1,3-butadiene, polyhydroxybutyrate (PHB) or citric acid |
| title_sort | techno economic analysis of integrated sugarcane biorefinery scenarios for the production of 2 3 butanediol 1 3 butadiene polyhydroxybutyrate phb or citric acid |
| topic | Sugar factories – Economic aspects -- South Africa Citric acid -- South Africa Biorefineries -- South Africa |
| url | http://hdl.handle.net/10019.1/127275 |
| work_keys_str_mv | AT gouwsmirellerene technoeconomicanalysisofintegratedsugarcanebiorefineryscenariosfortheproductionof23butanediol13butadienepolyhydroxybutyratephborcitricacid |