Evaluation of Novel CO2 Capture Process Concepts with CCGT Plant

  • Mohammad Nahyan Arshad Ansari

Student thesis: Master's Thesis

Abstract

This thesis aims to reduce the high energy penalty associated with MEA based CO2 capture process by implementing a hybrid solution. This involves introduction of optimum combination of process configurations as well as replacement of MEA with MDEA/PZ blend having lower energy requirement. As various process configurations form several possible combinations, this thesis aims to develop a systematic approach to consider all different combinations and the synergistic effects of combining different process configurations in one flowsheet in order to identify the optimum combination. The thesis provides a comprehensive investigation on the technoeconomic performance of MEA and MDEA/PZ based post combustion capture process integrated to a 750MW Combined Cycle Gas Turbine (CCGT) power plant. Rigorous rate-based models were developed in Aspen Plus to evaluate the technical performance while a comprehensive economic model was developed to evaluate the economic performance. The good agreement between the simulation model results and CCGT pilot plant data concluded that the developed rate-based model can accurately predict the CO2 capture by aqueous amines. Moreover, parametric studies were performed to evaluate the effect of various parameters on the regeneration energy which helped to identify the optimum value for each parameter. In addition, the thesis highlights that the current trend in literature studies of evaluating any novel solvent or process configuration based on only one key performance indicator (regeneration energy savings) can be misleading. For example, IHS configuration resulted in 8.85% energy savings in MEA case; however, the high capital cost of interstage heat exchanger and interstage pump resulted in overall negative cost savings (-2.04%). Hence, this thesis concludes that evaluation of any novel solvent or process configuration depends on two key performance indicators: Regeneration Energy Savings and Levelized Capture Cost Savings. The main results of the regeneration energy and economic analysis in this thesis revealed that replacing MEA with MDEA/PZ blend along with introducing an optimum combination of three process configurations (AIC+RSS+LVC) resulted in minimum regeneration energy of 2.17 GJ/tCO2 and minimum levelized cost of capture and compression of 49.28 $/tCO2.
Date of AwardJul 2022
Original languageAmerican English

Keywords

  • Hybrid
  • process configurations
  • regeneration energy
  • levelized capture cost and optimization.

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