Optimization and energy assessment of technological process for CO2 capture system of natural gas and coal combustion

Abstract

Flue gas stream generated from combusted natural gas, petroleum, and coal in power plants contains enormous CO2 with detrimental effects on the environment. CO2 capture systems must be integrated into these power plants to prevent emissions of CO2 into the open atmosphere. This work uses rate-based process modelling and a parametric design approach to optimally design large-scale amine-based PCC and compression systems that can be integrated into real 550 MW coal-fired and 555MW NGCC fired power plants. A comparative analysis of energy and economy is also conducted. Based on monoethanolamine (MEA), the process parameters of the post-combustion capture and compression system for CO2 were used as the study baseline. Different amines and alternative flow scheme optimization of the post-combustion capture with compression models are developed for coal and natural gas combined cycle (NGCC) cases and their energy consumption performances compared. Also, the operating and capital costs of the CO2 Capture and Storage (CCS) plant are determined for the overall process of economic evaluation concerning technical and economic performance parameters. The results show that rich solvent cooled recycle (RSR) and lean vapour compression (LVC) process modification under the integration case of CO2 capture and compressed Coal, energy savings of 20.4%, 41.8% and 34.8% for MEA, piperazine activated methyldiethanolamine solution (MDEA+PZ) and piperazine activated monoethanolamine (MEA+PZ) respectively, is possible when compared with the basic situation of MEA. RSR+LVC process modification under the integration case of CO2 capture and compressed NGCC, energy savings of 18.9%, 35.4% and 34.4% for MEA, MDEA+PZ and MEA+PZ, respectively, is possible when compared with the basic situation of MEA. Economic performance: the total annual operating costs of MDEA+PZ, RSR+LVC technological process optimized for the coal case was reduced by approximately 30% compared with the basic situation of MEA, while that for the NGCC case was reduced by 19%. The cost of CO2 avoided for the coal used MDEA+PZ into RSR+LVC technological process optimized capture is decreased by 13% compared with coal captured in MEA basic situation. For the NGCC cases, the cost of CO2 avoided for the NGCC of MDEA+PZ, RSR+LVC process optimized capture is decreased by 7% compared with NGCC with MEA basic case capture.