The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform
Nilay Shah - One of the best experts on this subject based on the ideXlab platform.
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Multiscale design and analysis of CO2 networks
International Journal of Greenhouse Gas Control, 2020Co-Authors: Ahmed Alhajaj, Nilay ShahAbstract:Abstract Carbon Capture and Storage (CCS) is an essential technology for CO2 emissions reductions, which will allow us to continue consuming fossil fuels in the short to medium term. In this work, we developed a multiscale modeling and optimization approach that links detailed models of the capture plant, Compression Train and pipelines with the CO2 supply-chain network model. This was used to find the cost-optimal CO2 network considering a case-study of meeting a national reduction target in the United Arab Emirates that supplies CO2 for EOR activities. The main decision variables were the optimal location and operating conditions of each CO2 capture and Compression plant in addition to the topology and sizing of the pipelines while considering the whole-system behaviour. A key result of our study was that the cost-optimal degree of capture should be included as a degree of freedom in the design of CO2 networks and it is a function of several site-specific factors, including exhaust gas characteristics, proximity to transportation networks and adequate geological storage capacity. This conclusion serves to underscore the need to comprehend the science governing the physical behaviour at different scales and the importance of a whole-system analysis of potential CO2 networks.
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A techno-economic analysis of post-combustion CO2 capture and Compression applied to a combined cycle gas turbine: Part I. A parametric study of the key technical performance indicators
International Journal of Greenhouse Gas Control, 2016Co-Authors: Ahmed Alhajaj, Niall Mac Dowell, Nilay ShahAbstract:Abstract In order to mitigate significant capital expenditure and parasitic energy demands associated with post combustion capture plant, many studies focused on improving its performance and efficiency through improvement in the design, integration of utilities and selection of key operating parameters (KOPs) using various key performance indicators (KPIs). In this study, an equilibrium monoethanolamine-based CO2 capture plant and Compression Train model was developed, validated and then used to assess the effects of KOPs on the performance of the CO2 capture and Compression process applied to a 400 MWe combined cycle gas turbine (CCGT) power plant in hot countries using selected non-monetized key economic and environmental performance indicators. These were selected so as to allow performance comparisons without resorting to economic assumptions (e.g., discount rates, costs of energy), which make such comparisons difficult. The results illustrate higher Compression power and dramatic increase of cooling water requirements in coolers and washing water systems in hot countries. This work elucidates the complex compromise between minimizing capital and operating expenditure indicators, and environmental impacts. It highlights the importance of considering the whole process, as opposed to simply focusing on the energy penalty associated with solvent regeneration.
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A techno-economic analysis of post-combustion CO2 capture and Compression applied to a combined cycle gas turbine: Part II. Identifying the cost-optimal control and design variables
International Journal of Greenhouse Gas Control, 2016Co-Authors: Ahmed Alhajaj, Niall Mac Dowell, Nilay ShahAbstract:Abstract A detailed optimization-orientated model of monoethanolamine-based CO 2 capture plant and Compression Train in which all the technical and economic assumptions are defined and/or optimized was developed and used to simultaneously determine the cost optimal control and design variables including feed fraction ratio at different degrees of capture (DOC), which represents the amount of CO 2 removed, for plant designs that partially bypass the CO 2 capture process so as to achieve low to moderate reductions of CO 2 , but at lower overall cost. The effects of varying carbon prices on the levelized cost of CO 2 capture and Compression were also studied. The capture bypass option was observed to be the cost optimal choice for lower than 60% overall DOC. Carbon prices were observed to have a clear impact on the cost optimal DOC, with the cost-optimal DOC shifting from 70%⿿80% to 85%⿿90% at carbon prices of $4/t CO 2 to $23/t CO 2 respectively. The study highlighted that if a suitably high carbon price does not materialize through a market mechanism, appropriate policies need to be put in place to achieve decarbonisation targets.
Ahmed Alhajaj - One of the best experts on this subject based on the ideXlab platform.
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Multiscale design and analysis of CO2 networks
International Journal of Greenhouse Gas Control, 2020Co-Authors: Ahmed Alhajaj, Nilay ShahAbstract:Abstract Carbon Capture and Storage (CCS) is an essential technology for CO2 emissions reductions, which will allow us to continue consuming fossil fuels in the short to medium term. In this work, we developed a multiscale modeling and optimization approach that links detailed models of the capture plant, Compression Train and pipelines with the CO2 supply-chain network model. This was used to find the cost-optimal CO2 network considering a case-study of meeting a national reduction target in the United Arab Emirates that supplies CO2 for EOR activities. The main decision variables were the optimal location and operating conditions of each CO2 capture and Compression plant in addition to the topology and sizing of the pipelines while considering the whole-system behaviour. A key result of our study was that the cost-optimal degree of capture should be included as a degree of freedom in the design of CO2 networks and it is a function of several site-specific factors, including exhaust gas characteristics, proximity to transportation networks and adequate geological storage capacity. This conclusion serves to underscore the need to comprehend the science governing the physical behaviour at different scales and the importance of a whole-system analysis of potential CO2 networks.
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A techno-economic analysis of post-combustion CO2 capture and Compression applied to a combined cycle gas turbine: Part I. A parametric study of the key technical performance indicators
International Journal of Greenhouse Gas Control, 2016Co-Authors: Ahmed Alhajaj, Niall Mac Dowell, Nilay ShahAbstract:Abstract In order to mitigate significant capital expenditure and parasitic energy demands associated with post combustion capture plant, many studies focused on improving its performance and efficiency through improvement in the design, integration of utilities and selection of key operating parameters (KOPs) using various key performance indicators (KPIs). In this study, an equilibrium monoethanolamine-based CO2 capture plant and Compression Train model was developed, validated and then used to assess the effects of KOPs on the performance of the CO2 capture and Compression process applied to a 400 MWe combined cycle gas turbine (CCGT) power plant in hot countries using selected non-monetized key economic and environmental performance indicators. These were selected so as to allow performance comparisons without resorting to economic assumptions (e.g., discount rates, costs of energy), which make such comparisons difficult. The results illustrate higher Compression power and dramatic increase of cooling water requirements in coolers and washing water systems in hot countries. This work elucidates the complex compromise between minimizing capital and operating expenditure indicators, and environmental impacts. It highlights the importance of considering the whole process, as opposed to simply focusing on the energy penalty associated with solvent regeneration.
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A techno-economic analysis of post-combustion CO2 capture and Compression applied to a combined cycle gas turbine: Part II. Identifying the cost-optimal control and design variables
International Journal of Greenhouse Gas Control, 2016Co-Authors: Ahmed Alhajaj, Niall Mac Dowell, Nilay ShahAbstract:Abstract A detailed optimization-orientated model of monoethanolamine-based CO 2 capture plant and Compression Train in which all the technical and economic assumptions are defined and/or optimized was developed and used to simultaneously determine the cost optimal control and design variables including feed fraction ratio at different degrees of capture (DOC), which represents the amount of CO 2 removed, for plant designs that partially bypass the CO 2 capture process so as to achieve low to moderate reductions of CO 2 , but at lower overall cost. The effects of varying carbon prices on the levelized cost of CO 2 capture and Compression were also studied. The capture bypass option was observed to be the cost optimal choice for lower than 60% overall DOC. Carbon prices were observed to have a clear impact on the cost optimal DOC, with the cost-optimal DOC shifting from 70%⿿80% to 85%⿿90% at carbon prices of $4/t CO 2 to $23/t CO 2 respectively. The study highlighted that if a suitably high carbon price does not materialize through a market mechanism, appropriate policies need to be put in place to achieve decarbonisation targets.
Robin Smith - One of the best experts on this subject based on the ideXlab platform.
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application of optimal design methodologies in retrofitting natural gas combined cycle power plants with co2 capture
Applied Energy, 2016Co-Authors: Ming Pan, Nan Zhang, Farah Aziz, Simon Perry, Igor Bulatov, Robin SmithAbstract:Abstract Around 21% of the world’s power production is based on natural gas. Energy production is considered to be the significant sources of carbon dioxide (CO 2 ) emissions. This has a significant effect on the global warming. Improving power plant efficiency and adding a CO 2 capture unit into power plants, have been suggested to be a promising countermeasure against global warming. This paper presents a new insight to the application of energy efficient technologies in retrofitting natural gas combined cycle (NGCC) power plants with CO 2 capture. High fidelity models of a 420 MW NGCC power plant and a CO 2 capture plant with CO 2 Compression Train have been built and integrated for 90% capture level. These models have been then validated by comparisons with practical operating data and literature results. The novelty of the paper is to propose optimal retrofitting strategies to minimize the efficiency penalty caused by integrating carbon capture units into the power plant, including (1) implementing heat transfer intensification techniques to increase energy saving in the heat recovery steam generator (HRSG) of the power plant; (2) extracting suitable steam from the HRSG to supply the heat required by the capture process, thus on external heat is purchased; (3) employing exhaust gas recirculation (EGR) to increase the overall energy efficiency of the integrated process, which can benefit both power plant (e.g. increasing power plant efficiency) and capture process (e.g. reducing heat demands). Compared with the base case without using any integrating and retrofitting strategies, the optimal solution based on the proposed approaches can provide sufficient heat to CO 2 capture process, and keep the same power generation. The optimal solution shows that, the flue gas flow-rate is reduced 33% in the inlet of CO 2 capture process, heat demand in CO 2 capture decreases 4.3%, heat output from the power plant increases from 0 MW to 133 MW, and more than 22% of profit is obtained in the integrated system. This demonstrates the validity and efficiency of the proposed approaches in retrofitting existing NGCC power plants with CO 2 capture.
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Techno-economic optimization of IGCC integrated with utility system for CO2 emissions reduction?Maximum power production in IGCC
Chemical Engineering Research and Design, 2013Co-Authors: Mona Gharaie, Megan Jobson, M. Hassan Panjeshahi, Nan Zhang, Robin SmithAbstract:Abstract Environmental legislation, with its increasing pressure on the energy sector to control greenhouse gases, is a driving force to reduce CO2 emissions. In this paper, pre-combustion CO2 capture through integration of a site utility system with an integrated gasification combined cycle (IGCC) is investigated as an option to provide a compressed CO2-rich stream from a process site for sequestration. This work presents a two-step procedure for integration and optimization of a site utility system with an IGCC plant: (i) screening and optimization of IGCC plant performance parameters; (ii) integration and optimization of the utility system of the site with the IGCC plant. In the first step, an optimization approach applies the results of screening studies based on rigorous simulation of the IGCC. Having fixed the inlet fuel flow rate, the IGCC design parameters (including oxygen consumption, diluent flow rate and turbine exit pressure) are optimized for maximum power generation. Energy flows between the IGCC and CO2 Compression Train are considered. In the second step, the economic and operating performance of the utility system integrated with the IGCC plant are modeled and optimized for minimum operating cost to find the most appropriate level of integration. In a case study illustrating the approach, 94% of the fuel is gasified; additional power generation offsets the operating costs of pre-combustion CO2 capture.
Meihong Wang - One of the best experts on this subject based on the ideXlab platform.
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Optimal Operation of MEA-Based Post-Combustion Carbon Capture Process for Natural Gas Combined Cycle Power Plants
Exergy for A Better Environment and Improved Sustainability 1, 2018Co-Authors: Xiaobo Luo, Meihong WangAbstract:Carbon capture for fossil fuel power generation draws an increasing attention because of significant challenges of global climate change. This paper aims to explore the optimal operation of MEA-based post-combustion carbon capture (PCC) process for natural gas combined cycle (NGCC) power plant. Levelized cost of electricity (LCOE) is formulated as the objective function to be minimized in optimization. The rate-based steady state process model including the absorber, stripper and Compression Train and other auxiliary equipment was developed in Aspen Plus® to give accurate prediction of process performance. The techno-economic estimate was carried out for the base case for whole chain of NGCC integrated with PCC, CO2 transport and storage (TS thus a higher carbon price is needed to re-justify the cost of high carbon capture level of PCC process.
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Optimal operation of MEA-based post-combustion carbon capture for natural gas combined cycle power plants under different market conditions
International Journal of Greenhouse Gas Control, 2016Co-Authors: Xiaobo Luo, Meihong WangAbstract:Carbon capture for fossil fuel power generation attracts an increasing attention in order to address the significant challenge of global climate change. This study aims to explore the optimal operation under different market conditions for an assumed existing natural gas combined cycle (NGCC) power plant integrated with MEA-based post-combustion carbon capture (PCC) process. The steady state process models for NGCC power plant, PCC process and CO2 Compression Train were developed in Aspen Plus® to give accurate prediction of process performance. Levelised cost of electricity (LCOE) is formulated as the objective function in optimization studies. Economic evaluation was carried out for the base case of the integrated system including CO2 transport and storage (T&S). The optimal operations were investigated for the carbon capture level under different carbon price, fuel price and CO2 T&S price. The study shows that carbon price needs to be over €100/ton CO2 to justify the total cost of carbon capture from the NGCC power plant and needs to be €120/ton CO2 to drive carbon capture level at 90%. Higher fuel price and CO2 T&S price would cause a higher operating cost of running carbon capture process thus a higher carbon price is needed if targeted carbon capture level is to be maintained.
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heat integration of natural gas combined cycle power plant integrated with post combustion co2 capture and Compression
Fuel, 2015Co-Authors: Xiaobo Luo, Meihong Wang, Jian ChenAbstract:Abstract Carbon capture for fossil fuel power generation draws an increasing attention because of significant challenges of global climate change. This study aims to explore the integration of a 453 MW e natural gas combined cycle (NGCC) power plant with an MEA-based post-combustion carbon capture (PCC) process and CO 2 Compression Train. The steady state models of the NGCC power plant, the PCC process and Compression Train were developed using Aspen Plus® and were validated with the published data and experimental data. The interfaces between NGCC and PCC were discussed. Exhaust gas recirculation (EGR) was also investigated. With EGR, a great size reduction of the absorber and the stripper was achieved. An advanced supersonic shock wave compressor was adopted for the CO 2 Compression and its heat integration was studied. The case study shows net efficiency based on low heating value (LHV) decreases from 58.74% to 49.76% when the NGCC power plant is integrated with the PCC process and Compression. Addition of EGR improves the net efficiency to 49.93% and two Compression heat integration options help to improve the net efficiency to 50.25% and 50.47% respectively. This study indicates NGCC including EGR integrated with PCC and supersonic shock wave Compression with new heat integration opportunity would be the future direction of carbon capture deployment for NGCC power plant.
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Simulation-based techno-economic evaluation for optimal design of CO2 transport pipeline network
Applied Energy, 2014Co-Authors: Xiaobo Luo, Meihong Wang, Eni Oko, Chima OkezueAbstract:Abstract For large volumes of carbon dioxide (CO 2 ) onshore and offshore transportation, pipeline is considered the preferred method. This paper presents a study of the pipeline network planned in the Humber region of the UK. Steady state process simulation models of the CO 2 transport pipeline network were developed using Aspen HYSYS®. The simulation models were integrated with Aspen Process Economic Analyser® (APEA). In this study, techno-economic evaluations for different options were conducted for the CO 2 Compression Train and the trunk pipelines respectively. The evaluation results were compared with other published cost models. Optimal options of Compression Train and trunk pipelines were applied to form an optimal case. The overall cost of CO 2 transport pipeline network was analyzed and compared between the base case and the optimal case. The results show the optimal case has an annual saving of 22.7 M€. For the optimal case, levelized energy and utilities cost is 7.62 €/t-CO 2 , levelized capital cost of trunk pipeline is about 8.11 €/t-CO 2 and levelized capital cost of collecting system is 2.62 €/t- CO 2 . The overall levelized cost of the optimal case was also compared to the result of another project to gain more insights for CO 2 pipeline network design.
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Techno-Economic Analysis of a Natural Gas Combined Cycle Power Plant with CO2 Capture
Computer Aided Chemical Engineering, 2013Co-Authors: Chechet Biliyok, Meihong Wang, Roberto Canepa, Hoi YeungAbstract:Abstract Power generation via natural gas is projected to increase over the next decade. CO2 capture would be required to mitigate the associated emissions. Integrating a capture plant to power plants can be explored via process simulation. Hence, high fidelity models of a natural gas combined cycle power plant and a post-combustion capture plant were built – a 440MW power plant model that is tuned and validated with data from GE’s GateCycle®, and a rate-based capture plant model that is scaled up from a previously validated model. Along with a suitably sized Compression Train, the plants are integrated for 90% CO2 capture. Net power output is observed to fall by 14%, but cooling water demand increases by 33%. A 40% exhaust gas recirculation (EGR) results in a marginal recovery in output, but also raises cooling water demand further. A redesign of the steam cycle to account for integration would potentially improve performance. Economic analysis is performed via a bottom-up approach. The integrated plant overnight cost is determined to be 45% higher than cost of the power plant without capture, but is only 43% higher with EGR. The cost of electricity also increases by 41% for the integrated plant, but by only 38% with EGR. Lastly, the cost of CO2 avoided is estimated to be €69 per ton of CO2, but reduces to €63 with EGR.
Yann Le Moullec - One of the best experts on this subject based on the ideXlab platform.
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Vacuum Regeneration of Amine Solvent for Post-Combustion Carbon Capture with Compression Train Integration
Energy Procedia, 2013Co-Authors: Yann Le MoullecAbstract:Abstract The main aim of this study is the assessment of vacuum operating pressure for amine based solvent regeneration with respect to plant efficiency and economic in order to conclude about its industrial potential. The capture process considered is the conventional two columns configuration with MEA solvent. A regeneration pressure range from 0.06 to 2.5 bar have been investigated. The thermal integration with the power plant has been performed on a new built, advanced supercritical power plant adapted for CO 2 capture. Flue gases condensation heat and CO 2 Compression heat have been fully integrated in the steam cycle. Influence of stripper pressure on optimal lean loading ratio and columns basic design (height and diameter) have been investigated, with a focus on the influence of the CO 2 Compression heat integration strategy. Calculations of plant efficiency have been completed by simplified economical calculations for the levelized cost of electricity (LCOE) and avoided CO 2 (LCCO 2 ) in order to assess the industrial interest of stripper vacuum operation. Regarding plant efficiency the optimal pressure is at the minimum value: i.e. 0.06 bar with a loss of efficiency of 7.6%pt. In the pressure range from 0.5 bar (medium vacuum) to 2.5 bar (standard stripper pressure), plant efficiency is quite stable with a minimum around atmospheric pressure with 9.4%pt loss of efficiency. Regarding plant economics the main impact of vacuum regeneration is not the cost of the larger stripper but the cost of the very large compressor needed to maintain vacuum condition. At very low pressure, absorber and stripper have the same operating temperature therefore the economizer is no longer needed. Coupled with the improved plant efficiency, the effect of pressure on cost of electricity and cost of avoided CO 2 is very small. The expected gain for deep vacuum stripper is not large enough to justify pilot demonstration of such operating parameters.
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Assessment of carbon capture thermodynamic limitation on coal-fired power plant efficiency
International Journal of Greenhouse Gas Control, 2012Co-Authors: Yann Le MoullecAbstract:Abstract The most mature CO 2 carbon capture process comes with a 12–10% pts efficiency loss when coupled with a coal-fired power plant and for both post and oxy-combustion. Pre-combustion induces less efficiency loss but at the cost of a more complicated overall process. Since the last decade numerous improvements have been made and this work tries to evaluate the thermodynamic minimum impact of CO 2 capture processes on such coal power plants. After detailing the calculation hypothesis, the purely thermodynamic impact has been assessed: they are 3.2% pt for post-combustion divided into 40% for separation and 60% for Compression, 4.2% for pre-combustion especially due to CO-shift (60%), the rest evenly divided between separation and Compression and 2.9% for oxy-combustion divided into one third for O 2 production and two thirds for Compression and with a small efficiency gain compared to aero-combustion due to the reduction in flue gas volume. In the second part of this work, the realistic minimum energy consumption is assessed with some assumptions about compressor and pump efficiency, temperature pinch and overall process conditions. This study shows a 6.8% pt loss of efficiency for MEA absorption post-combustion process combined with classical Compression Train, 5.8% pt for a cryogenic post-combustion process, 6.6% pt for a MDEA absorption pre-combustion process with classical Compression Train, 5.4% pt for the cryogenic ASU oxy-combustion with standard cryogenic CPU. These realistic minimal impacts of CO 2 capture on supercritical coal power plants highlight the difficulty in designing a process with less than 5% pt of efficiency loss which is the main technological challenge of the CO 2 capture field at the moment. The better performance achievable seems around 6.0% pt loss of efficiency with good integrated low regeneration duty solvent for post-combustion or highly efficient ASU and CPU for oxy-combustion. However, a power plant practical efficiency of more than 40% is readily achievable with a well designed IGCC plant and, in near future, with USCPC power plant.