Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration
Makakavhule, N. 2025. Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/195a5c6e-0970-4305-9919-00b557...
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Published: |
Stellenbosch : Stellenbosch University
2025
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613769719349248 |
|---|---|
| access_status_str | Open Access |
| author | Makakavhule, Nduvho |
| author2 | Naidoo, Paramespri |
| author_browse | Makakavhule, Nduvho Naidoo, Paramespri |
| author_facet | Naidoo, Paramespri Makakavhule, Nduvho |
| author_sort | Makakavhule, Nduvho |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Makakavhule, N. 2025. Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/195a5c6e-0970-4305-9919-00b557928b9b |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132639 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:41:24.431Z |
| 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:10019.1/132639 Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration Makakavhule, Nduvho Naidoo, Paramespri Stellenbosch University. Faculty of Engineering. Dept. of Chemical Engineering. Methanol -- Synthesis Sequestration (Chemistry) Hydrogenation Blast furnace gas Greenhouse gases -- Environmental aspects UCTD Makakavhule, N. 2025. Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/195a5c6e-0970-4305-9919-00b557928b9b Thesis (MEng)--Stellenbosch University, 2025. ENGLISH ABSTRACT: The synthesis of low-carbon methanol from CO₂ and H₂ was examined using two carbon capture processes, amine absorption with methyldiethanolamine (MDEA) and Vacuum Pressure Swing Adsorption (VPSA), both enhanced by a Water Gas Shift (WGS) reactor. This novel study focused on capturing CO₂ from Blast Furnace Gas (BFG) in the iron and steel industry for methanol production through CO₂ hydrogenation comparing the two carbon capture processes with heat integration. Methanol holds significance beyond its role as a chemical feedstock, emerging as an attractive alternative fuel due to its ease of storage and diverse applications in fuel and chemical processes. As a versatile, globally traded chemical, it serves as a vital feedstock for the chemical industry and as an energy carrier, contributing to products such as paints, textiles, solvents, and plastics. Industry projections indicate substantial growth in methanol demand by 2050, driven by advancements in petrochemical technologies, including methanol-to-olefins (MTO), methanol-to-gasoline (MTG), and methanol-to-propylene (MTP). Additionally, renewable methanol production using green hydrogen and captured CO₂ is expected to play a significant role in meeting future demand. This research evaluated three methanol production capacities for both the amine and VPSA carbon capture plants by adjusting the BFG feed rates: 148 kg/s (capacity 1), 29.5 kg/s (capacity 2), and 5.91 kg/s (capacity 3). The amine plant achieved methanol outputs of 261 kt/a, 52 kt/a, and 10 kt/a, while the VPSA plant produced 275 kt/a, 55 kt/a, and 11 kt/a. Analysis of key plant parameters revealed significant variations in energy efficiency between the two systems. The VPSA system was significantly more energy efficient, requiring approximately 88% less energy for the storage and utilization of 1 kg of captured CO2 and the production of 1 ton of methanol, using only 12% of the energy consumed by the amine plant. For the regeneration duty, the amine plant required 41% more energy per ton of BFG, due to the thermal intensive solvent regeneration in the stripper reboiler, while the VPSA system used only 59% of this energy. The WGS steam requirement to produce 1 kg of methanol was 5% higher in the amine plant, with the VPSA plant consuming only 95% of the steam required by the amine system. Conversely, the VPSA plant exhibited a 22% higher electricity demand per ton of methanol, driven by the continuous operation of vacuum pumps, meaning the amine plant used 78% of the electricity required by the VPSA system. These results highlight the trade-offs between the two systems, with the VPSA system offering superior energy efficiency in most aspects, despite its higher electricity consumption. Heat integration analysis demonstrated significant improvements in thermal efficiency for both systems. The efficiency for the amine-based process increased from approximately 30% to 50% after heat integration, while for the VPSA systems a smaller improvement from approximately 45% to 55% was observed. The amine system's larger efficiency gains were attributed to its complex heat exchange network and higher energy demands for solvent regeneration, creating additional heat integration opportunities. Economic analysis through carbon tax and credit calculations revealed that plants with carbon capture technology are more economically viable than those without. At maximum capacity, the amine process generated annual carbon credits of R4.08 billion, resulting in a net gain of R4.00 billion after carbon deductions. The VPSA plant produced R3.92 billion in annual carbon credits, with a net gain of R3.84 billion, showing slightly lower profitability (4% less) compared to the amine plant. The study demonstrated clear economies of scale, with larger plant capacities yielding significantly higher annual net impacts. The highest capacity configuration (148 kg/s of BFG) showed the potential to generate approximately five times more profit than the medium capacity and twenty-five times more than the lowest capacity, highlighting the economic advantages of larger scale operations. This profitability was primarily driven by carbon credits earned from storing and utilizing the captured CO₂ rather than emitting it. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Masters 2025-06-12T07:38:02Z 2025-06-12T07:38:02Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132639 Stellenbosch University xxi, 213 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Methanol -- Synthesis Sequestration (Chemistry) Hydrogenation Blast furnace gas Greenhouse gases -- Environmental aspects UCTD Makakavhule, Nduvho Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration |
| title | Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration |
| title_full | Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration |
| title_fullStr | Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration |
| title_full_unstemmed | Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration |
| title_short | Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration |
| title_sort | sustainable methanol production from blast furnace gas comparing carbon capture techniques and optimizing hydrogen integration |
| topic | Methanol -- Synthesis Sequestration (Chemistry) Hydrogenation Blast furnace gas Greenhouse gases -- Environmental aspects UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132639 |
| work_keys_str_mv | AT makakavhulenduvho sustainablemethanolproductionfromblastfurnacegascomparingcarboncapturetechniquesandoptimizinghydrogenintegration |