Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
The synthesis of Combined Heat and Mass Exchange Networks (CHAMENs) with renewables considering environmental impact
Process synthesis is used to evaluate different potential designs to select the most suitable that fulfils some process goals. There is ever-increasing pressure to reduce operating cost and emission of pollutants as energy prices continue to increase and more regulations are set by government. To ad...
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
Department of Chemical Engineering
2020
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613178660126720 |
|---|---|
| access_status_str | Open Access |
| author | Kim, So-Mang |
| author2 | Isafiade, Adeniyi J |
| author_browse | Isafiade, Adeniyi J Kim, So-Mang |
| author_facet | Isafiade, Adeniyi J Kim, So-Mang |
| author_sort | Kim, So-Mang |
| collection | Thesis |
| description | Process synthesis is used to evaluate different potential designs to select the most suitable that fulfils some process goals. There is ever-increasing pressure to reduce operating cost and emission of pollutants as energy prices continue to increase and more regulations are set by government. To address these concerns, optimisation methods based on heuristics, pinch technology and mathematical programming can be adopted. Since the early 90s, mathematical programming has gained significant attention to solve large and complex problems. Extensive studies have been conducted for heat exchange network synthesis (HENS), which was first used to optimise utility usage and operating costs. Many existing mass exchange network synthesis (MENS) methods are derived from HENS techniques since analogies exist between the two networks. Integrating the synthesis of mass and heat exchange networks in what is known as combined heat and mass exchange network synthesis (CHAMENS) can be beneficial because mass transfer is affected by operating temperature. However, very little research has been done in this area of process synthesis due to their complex nature. It is even more challenging to find literature involving the regeneration of multiple recyclable MSAs in a network synthesis context. Furthermore, the few studies that have considered CHAMENS have done the optimisation considering economic performance alone, whereas the consideration of environmental impact as an additional objective can help attain a more sustainable process. This thesis builds on current knowledge of CHAMENs synthesis methods by considering CHAMENs with detailed regeneration networks (RENs) involving multiple recyclable MSAs, multiple regenerating streams, and solar thermal as an alternative energy source, using a multi-period synthesis approach. Simultaneously optimising a combination of these networks is not a trivial task due to the resulting large model size having many binary and non-linear terms and the interactions among them. Stage-wise superstructure (SWS) synthesis approaches for heat and mass exchanger networks are adopted in this thesis for the synthesis of CHAMENs. A new superstructure for RENs, which is equivalent to that of a MEN, is presented in this thesis. The combined superstructure, which involves multiple MSAs, multiple regenerants, and multiple hot and cold process streams, is integrated with solar thermal energy as a renewable energy option. The availability of solar thermal energy is simplified by discretizing into two time periods of daytime and nighttime operations. The proposed CHAMEN model is also extended to handle multi-objective optimisation (MOO) of environmental impact and economic objectives to identify the optimal network configuration. Two examples were solved, and the results obtained showed that the implementation of integrated solar panels and thermal storage tanks could reduce the environmental impact of the combined networks by 76% and 26% for case studies 1 and 2 respectively. However, such eco-friendly infrastructure resulted in increased total annual cost (TAC) values of 36% and 15% respectively for the two case studies. These results indicate that by using the methodologies developed in this thesis, trade-offs can be established between economics and environmental impact as objectives. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/31376 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:00.945Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2020 |
| publishDateRange | 2020 |
| publishDateSort | 2020 |
| publisher | Department of Chemical Engineering |
| publisherStr | Department of Chemical Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/31376 The synthesis of Combined Heat and Mass Exchange Networks (CHAMENs) with renewables considering environmental impact Kim, So-Mang Isafiade, Adeniyi J Chemical Engineering Process synthesis is used to evaluate different potential designs to select the most suitable that fulfils some process goals. There is ever-increasing pressure to reduce operating cost and emission of pollutants as energy prices continue to increase and more regulations are set by government. To address these concerns, optimisation methods based on heuristics, pinch technology and mathematical programming can be adopted. Since the early 90s, mathematical programming has gained significant attention to solve large and complex problems. Extensive studies have been conducted for heat exchange network synthesis (HENS), which was first used to optimise utility usage and operating costs. Many existing mass exchange network synthesis (MENS) methods are derived from HENS techniques since analogies exist between the two networks. Integrating the synthesis of mass and heat exchange networks in what is known as combined heat and mass exchange network synthesis (CHAMENS) can be beneficial because mass transfer is affected by operating temperature. However, very little research has been done in this area of process synthesis due to their complex nature. It is even more challenging to find literature involving the regeneration of multiple recyclable MSAs in a network synthesis context. Furthermore, the few studies that have considered CHAMENS have done the optimisation considering economic performance alone, whereas the consideration of environmental impact as an additional objective can help attain a more sustainable process. This thesis builds on current knowledge of CHAMENs synthesis methods by considering CHAMENs with detailed regeneration networks (RENs) involving multiple recyclable MSAs, multiple regenerating streams, and solar thermal as an alternative energy source, using a multi-period synthesis approach. Simultaneously optimising a combination of these networks is not a trivial task due to the resulting large model size having many binary and non-linear terms and the interactions among them. Stage-wise superstructure (SWS) synthesis approaches for heat and mass exchanger networks are adopted in this thesis for the synthesis of CHAMENs. A new superstructure for RENs, which is equivalent to that of a MEN, is presented in this thesis. The combined superstructure, which involves multiple MSAs, multiple regenerants, and multiple hot and cold process streams, is integrated with solar thermal energy as a renewable energy option. The availability of solar thermal energy is simplified by discretizing into two time periods of daytime and nighttime operations. The proposed CHAMEN model is also extended to handle multi-objective optimisation (MOO) of environmental impact and economic objectives to identify the optimal network configuration. Two examples were solved, and the results obtained showed that the implementation of integrated solar panels and thermal storage tanks could reduce the environmental impact of the combined networks by 76% and 26% for case studies 1 and 2 respectively. However, such eco-friendly infrastructure resulted in increased total annual cost (TAC) values of 36% and 15% respectively for the two case studies. These results indicate that by using the methodologies developed in this thesis, trade-offs can be established between economics and environmental impact as objectives. 2020-02-28T08:00:06Z 2020-02-28T08:00:06Z 2019 2020-02-27T12:07:30Z Master Thesis Masters MSc http://hdl.handle.net/11427/31376 eng application/pdf Department of Chemical Engineering Faculty of Engineering and the Built Environment |
| spellingShingle | Chemical Engineering Kim, So-Mang The synthesis of Combined Heat and Mass Exchange Networks (CHAMENs) with renewables considering environmental impact |
| thesis_degree_str | Master's |
| title | The synthesis of Combined Heat and Mass Exchange Networks (CHAMENs) with renewables considering environmental impact |
| title_full | The synthesis of Combined Heat and Mass Exchange Networks (CHAMENs) with renewables considering environmental impact |
| title_fullStr | The synthesis of Combined Heat and Mass Exchange Networks (CHAMENs) with renewables considering environmental impact |
| title_full_unstemmed | The synthesis of Combined Heat and Mass Exchange Networks (CHAMENs) with renewables considering environmental impact |
| title_short | The synthesis of Combined Heat and Mass Exchange Networks (CHAMENs) with renewables considering environmental impact |
| title_sort | synthesis of combined heat and mass exchange networks chamens with renewables considering environmental impact |
| topic | Chemical Engineering |
| url | http://hdl.handle.net/11427/31376 |
| work_keys_str_mv | AT kimsomang thesynthesisofcombinedheatandmassexchangenetworkschamenswithrenewablesconsideringenvironmentalimpact AT kimsomang synthesisofcombinedheatandmassexchangenetworkschamenswithrenewablesconsideringenvironmentalimpact |