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- Mocholí Montañés, Rubén, 1990, et al.
(author)
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Demonstrating load-change transient performance of a commercial-scale natural gas combined cycle power plant with post-combustion CO2 capture
- 2017
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In: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836. ; 63, s. 158-174
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Journal article (peer-reviewed)abstract
- The present work aims to study the transient performance of a commercial-scale natural gas combined cycle (NGCC) power plant with post-combustion CO2 capture (PCC) system via linked dynamic process simulation models. The simulations represent real-like operation of the integrated plant during load change transient events with closed-loop controllers. The focus of the study was the dynamic interaction between the power plant and the PCC unit, and the performance evaluation of decentralized control structures. A 613 MW three-pressure reheat NGCC with PCC using aqueous MEA was designed, including PCC process scale-up. Detailed dynamic process models of the power plant and the post-combustion unit were developed, and their validity was deemed sufficient for the purpose of application. Dynamic simulations of three gas turbine load-change ramp rates (2%/min, 5%/min and 10%/min) showed that the total stabilization times of the power plant's main process variables are shorter (10–30 min) than for the PCC unit (1–4 h). A dynamic interaction between the NGCC and the PCC unit is found in the steam extraction to feed the reboiler duty of the PCC unit. The transient performance of five decentralized PCC plant control structures under load change was analyzed. When controlling the CO2 capture rate, the power plant performs in a more efficient manner at steady-state part load; however, the PCC unit experiences longer stabilization times of the main process variables during load changes, compared with control structures without CO2 capture rate being controlled. Control of L/G ratio of the absorber columns leads to similar part load steady-state performance and significantly faster stabilization times of the power plant and PCC unit's main process variables. It is concluded that adding the PCC unit to the NGCC does not significantly affect the practical load-following capability of the integrated plant in a day-ahead power market, but selection of a suitable control structure is required for efficient operation of the process under steady-state and transient conditions.
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| 3. |
- Normann, Fredrik, 1982, et al.
(author)
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Partial Capture of Carbon Dioxide from Industrial Sources - A Discussion on Cost Optimization and the CO2 Capture Rate
- 2017
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In: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 114, s. 113-121
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Conference paper (peer-reviewed)abstract
- This work discusses the cost optimal capture rate of absorption based carbon capture processes by a combination of process simulations and cost-estimation. The influence of the quality of the CO2 source (quantity, continuity and CO2 concentration) and the availability of low cost heat on the absolute and specific capture cost are highlighted. The results stress that partial capture of CO2 could lower the specific capture cost (€/ton CO2) and that the relation between capital expenditure and lowered energy demand should be reconsidered for cases with access to low-cost heat.
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| 4. |
- Òsk Gardarsdòttir, Stefanìa, 1987, et al.
(author)
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Effects of CO2-absorption control strategies on the dynamic performance of a supercritical pulverized-coal-fired power plant
- 2017
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In: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 1520-5045 .- 0888-5885. ; 56:15, s. 4415-4430
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Journal article (peer-reviewed)abstract
- This work investigates the interactions that occur between a supercritical pulverized-coal-fired power plant and a downstream CO2-absorption process during load changes in the power plant, by linking the dynamic models of the two systems. The derived dynamic model for this integrated system is implemented in the dynamic modeling and simulation software Dymola. The operation of the integrated system is investigated in two modes of operation, considering various power plant loads and levels of steam availability for the CO2-absorption process. Several schemes for control of the CO2-absorption process, which have been suggested in the literature, are implemented for the integrated system and their effects on power plant operation are evaluated. Comparison of the simulation results obtained through varying the power plant load with and without CO2 absorption reveal that the CO2-absorption process has slower process dynamics than the power plant cycle, with the CO2 absorption stabilizing in more than 1 hour, while the power generation generally stabilizes in 6–9 minutes, in the power plant both with and without CO2 absorption. The control scheme used for the CO2-absorption process is important, as pairing of the control variables in relatively slow control loops increases the settling time of the power plant by up to 30 minutes with respect to power output. The results suggest that the investigated CO2-absorption process does not affect significantly the load-following capabilities of the power plant. Redirecting steam from the CO2-absorption process to the low-pressure turbine section in order to increase power generation (during a hypothetical peak-load demand) results in fluctuations of process variables in the power plant during the 2 hours of reduced steam availability to the CO2-absorption process. This is observed for both control schemes applied to the CO2-absorption process, and the power generation is not stabilized until the operation is restored to full load.
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