Process simulation and parametric sensitivity study of CO2 capture from 115 MW coal–fired power plant using MEA–DEA blend

Abstract

This study used ProMax® 4.0 process simulator (rate–based model) to conduct a parametric sensitivity of carbon dioxide (CO2) capture from a 115 MW coal–fired power plant (Boundary Dam 3 power plant) using monoethanolamine (MEA) and diethanolamine (DEA) blend. Saskatchewan Power Corporation (SaskPower), Canada provided the flue gas composition used in this study. The validated simulation was used to determine the effects of some process variables (independent process variables) on different dependent process variables. The independent process variables are flue gas temperature (TFG, oC), lean amine temperature (TLA, oC), lean amine flow rate (FLA, tonne/day), lean amine concentration difference (CMEA–DEA, kmol/m3) and reboiler temperature (TREB, oC). The dependent process variables are MEA and DEA vaporization from the absorber, CO2 absorption efficiency (%), regeneration energy (GJ/tonne CO2), rich amine loading (RAL, mol CO2/mol amine) and lean amine loading (LAL, mol CO2/mol amine). Amine degradation was investigated by the O2 absorption rate (tonne O2/day), NO absorption rate (tonne NO/day) and NO2 absorption rate (tonne NO2/day). The vaporization rates of MEA (tonne MEA/day) and DEA (tonne DEA/day) were also investigated. The contribution of amine and water make–up costs, regeneration energy, pump electrical energy, blower electrical energy and compressor electrical energy towards variable operating expenditure (V–OPEX) were also investigated. Results showed that NO also contributes to amine degradation. From the parametric analysis it was observed that TREB has the greatest influence on most of the dependent process variables. It was also discovered that the regeneration energy, compressor electrical energy and amine, water make–up cost and cooling water contributed 82.5%, 12.3%, 1.1%, 0.9% and 0.5% of the V–OPEX respectively.