Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Techno-economic and environmental assessment of polylactic acid, polybutylene succinate and polybutylene adipate-co-terephthalate biorefineries annexed to a typical South African sugar mill
Ratshoshi, B. K. 2025. Techno-economic and environmental assessment of polylactic acid, polybutylene succinate and polybutylene adipate-co-terephthalate biorefineries annexed to a typical South African sugar mill. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Ava...
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
Stellenbosch : Stellenbosch University
2025
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613895979433984 |
|---|---|
| access_status_str | Open Access |
| author | Ratshoshi, Brankie Karabo |
| author2 | Gorgens, Johann F. |
| author_browse | Gorgens, Johann F. Ratshoshi, Brankie Karabo |
| author_facet | Gorgens, Johann F. Ratshoshi, Brankie Karabo |
| author_sort | Ratshoshi, Brankie Karabo |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Ratshoshi, B. K. 2025. Techno-economic and environmental assessment of polylactic acid, polybutylene succinate and polybutylene adipate-co-terephthalate biorefineries annexed to a typical South African sugar mill. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/5d2103a2-6413-4301-9bfb-e4662a858db1 |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132266 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:43:25.190Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/132266 Techno-economic and environmental assessment of polylactic acid, polybutylene succinate and polybutylene adipate-co-terephthalate biorefineries annexed to a typical South African sugar mill Ratshoshi, Brankie Karabo Gorgens, Johann F. Farzad, Somayeh Stellenbosch University. Faculty of Engineering. Dept. of Chemical Engineering. Sugar factories -- South Africa Biodegradable plastics -- South Africa Environmental impact analysis Biomass chemicals Biopolymers -- Environmental aspects UCTD Ratshoshi, B. K. 2025. Techno-economic and environmental assessment of polylactic acid, polybutylene succinate and polybutylene adipate-co-terephthalate biorefineries annexed to a typical South African sugar mill. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/5d2103a2-6413-4301-9bfb-e4662a858db1 Thesis (PhD)--Stellenbosch University, 2025. ENGLISH ABSTRACT: Production of synthetic plastics has increased drastically, with a worldwide production capacity of 359 million tons in 2018, which is already a threat to the environment. Biobased Polylactic acid (PLA), polybutylene succinate (PBS) and polybutylene adipate-co-terephthalate (PBAT) are of particular interest as they are biodegradable and could be produced from renewable biomass. This study investigated the techno-economic and environmental assessment of producing biobased PLA, PBS and PBAT in an energy-self-sufficient biorefinery annexed to a typical South African sugar mill.A typical South African sugar mill produces A or C molasses (a brown syrup obtained as a byproduct of sugarcane refining), sugarcane bagasse (dry fibrous material that remains after crushing sugarcane) and harvesting residues (brown leaves and tops resulting from sugarcane harvesting). However, these sugarcane materials can be valorised into a value-added product into a 1G, 2G and 1G2G biorefinery.A1G biorefinery uses A or C molasses as feedstock, a 2G utilises sugarcane bagasse and harvesting residues and 1G2G uses a combination of sugarcane molasses, bagasse and harvesting residue to produce biobased products. Process designs and flowsheets were developed using AspenPlus® software, based on available data from the literature.The 1G biorefineries were based on A molasses (25.4 tons/h) and the 2Gs on bagasse and harvesting residues (65.0 tons/h in a mass ratio of 1.0:2.3). The 1G2G PLA was based on A molasses, bagasse and harvesting residue (25.4 tons/h and 65 tons/h),while the 1G2G PBS biorefinery was based on C molasses (due to energy limitations to achieve an energy self-sufficient biorefinery), bagasse and harvesting residue (11.6 tons /h and 65.0 tons/h). Only 1G PBAT biorefinery was developed due to energy limitation and compared to the production of its most attractive monomers (1,4-butanediol). The mass and energy balances from the simulations were used to estimate the process equipment and utility cost, while the economic evaluation and sensitivity analysis were executed in Excel spreadsheets to evaluate PLA's, PBS's and PBAT’s economic feasibility. A life cycle assessment (LCA) study on the best-performing scenarios was conducted according to ISO 14040 and 14044 standards and compared with fossil-derived polyethylene terephthalate (PET), low-density polyethylene (LDPE), polystyrene (PS) and polypropylene (PP). A cradle-to-biorefinery gate approach was implemented in SimaPro 8.5 software to analyse the environmental burdens using the characterisation factors employed by the CML-IA baseline method developed by the Centre of Environmental Science of Leiden University. The simulation results have demonstrated that PBS scenarios were the most energy-intensive polymers, which required energy ranging from 5.1-8.2 MJ/kg of biomass and sugars processed compared to PLA scenarios (5.5-5.8 MJ/kg) and PBAT scenario (4.7 MJ/kg of sugars processed). These significantly impacted the production volume as PBS scenarios had a low production rate (24.4-47.3 kt/annum) and could not achieve economies of scale benefits. The techno-economic analysis of PBAT versus the 1,4-butanediol (BDO) scenario showed that both scenarios were economically feasible but producing BDO was beneficial owing to its higher internal rate of return (34.3%) compared to PBAT (19.1%) production. The 1G2G PLA scenario not only showed superior performance amongst the biodegradable polymers in terms of the economic metrics (minimum selling price of 2965 US$/ton at 20% internal rate of return) but also showed the best environmental performance with a global warming potential (GWP100a) of 0.58 CO2 eq./kg of PLA. The 1G PBS was the second-best performing scenario with a minimum selling price of 2980 US$/ton and GWP100a of 0.95 CO2 eq./kg of PBS followed by the 1G PLA (minimum selling price of 3320US$/ton and GWP100a of 1.03 CO2 eq./kg of PLA), while the 1G2G PBS and 1G PBAT showed the worst environmental performance with GWP100a of 4.33 CO2 eq./kg of PBS and 9.74 CO2 eq./kg of PBAT, respectively. The results of the investigated scenarios have shown that the production of 1G2G PLA and 1G PBS biorefineries in an energy-self-sufficient context are sustainable alternatives to fossil-derived polymers owing to their lower GWP100a (3.38 CO2 eq./kg of PS, 2.99 CO2 eq./kg PET, 1.97 CO2 eq./kg of PP and 2.1 CO2 eq./kg of LDPE) and comparable selling price (PET, LDPE, PS and PP were sold at 1500, 1382, 1800 and 2200 US$/ton respectively). AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Doctoral 2025-06-02T08:15:25Z 2025-06-02T08:15:25Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132266 en Stellenbosch University 240 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Sugar factories -- South Africa Biodegradable plastics -- South Africa Environmental impact analysis Biomass chemicals Biopolymers -- Environmental aspects UCTD Ratshoshi, Brankie Karabo Techno-economic and environmental assessment of polylactic acid, polybutylene succinate and polybutylene adipate-co-terephthalate biorefineries annexed to a typical South African sugar mill |
| title | Techno-economic and environmental assessment of polylactic acid, polybutylene succinate and polybutylene adipate-co-terephthalate biorefineries annexed to a typical South African sugar mill |
| title_full | Techno-economic and environmental assessment of polylactic acid, polybutylene succinate and polybutylene adipate-co-terephthalate biorefineries annexed to a typical South African sugar mill |
| title_fullStr | Techno-economic and environmental assessment of polylactic acid, polybutylene succinate and polybutylene adipate-co-terephthalate biorefineries annexed to a typical South African sugar mill |
| title_full_unstemmed | Techno-economic and environmental assessment of polylactic acid, polybutylene succinate and polybutylene adipate-co-terephthalate biorefineries annexed to a typical South African sugar mill |
| title_short | Techno-economic and environmental assessment of polylactic acid, polybutylene succinate and polybutylene adipate-co-terephthalate biorefineries annexed to a typical South African sugar mill |
| title_sort | techno economic and environmental assessment of polylactic acid polybutylene succinate and polybutylene adipate co terephthalate biorefineries annexed to a typical south african sugar mill |
| topic | Sugar factories -- South Africa Biodegradable plastics -- South Africa Environmental impact analysis Biomass chemicals Biopolymers -- Environmental aspects UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132266 |
| work_keys_str_mv | AT ratshoshibrankiekarabo technoeconomicandenvironmentalassessmentofpolylacticacidpolybutylenesuccinateandpolybutyleneadipatecoterephthalatebiorefineriesannexedtoatypicalsouthafricansugarmill |