Exergetic and exergoeconomic analysis of post-combustion CO2 capture using MEA-solvent chemical absorption

Abstract

Carbon Capture and Storage (CCS) has been acknowledged as a technology for CO2 emission reduction. However, developments to lower cost and energy consumption remains an important challenge.Exergetic and exergoeconomic analyses are methods which could be applied to optimize the energy consumption of CO2 capture technologies. An exergetic analysis reveals the locations and causes of inefficiency in an energy conversion process and provides options for improvements. An exergoeconomic analysis establishes the process of cost formation of different streams, including products, within energy systems based on exergy and economic cost balances. This paper aims to develop an exergy-based analysis of a post-combustion CO2 capture process using chemical absorption.A comprehensive flowsheet model has been built for an MEA-solvent chemical absorption, using ASPEN PlusTM Version 8.6 for a coal-fired power plant with a capture rate of 90%. Results have shown the highest irreversibilities to occur in the units related to the chemical capture of CO2 (77% of total losses) and in the CO2 pipeline compressor (9% of total losses). An improvement in the design of the plant reduces the unit cost of carbon capture from 35.0 US$/tonCO2 in the baseline case to of 31.8 US$/tonCO2.