Techno-Economic Evaluation of CO2 Capture in Biomass Boilers: A Comparison between MEA and DEA

Abstract

The increase in carbon dioxide (CO2) emissions has driven the development of mitigation technologies, with Bioenergy with Carbon Capture and Storage (BECCS) standing out as a promising alternative for achieving negative emissions. Among the available technologies, chemical absorption using amines presents a high level of industrial maturity. In this context, this study performed a technical and economic assessment of CO2 capture from the flue gas of a sugarcane bagasse–fired boiler with a flow rate of 200 t/h, corresponding to a steam production of 100 t/h. Monoethanolamine (MEA) and diethanolamine (DEA) were evaluated as solvents through simulations carried out in Aspen Plus®, considering both absorption and desorption stages. The results indicated a capture efficiency of 90% and a CO2 purity of 99%. The optimal liquid-to-gas mass ratio was 2.5 for MEA and 3.25 for DEA, corresponding to loadings of 0.30 and 0.40 mol CO2/mol solvent, respectively. The reboiler energy requirements were 4.4 and 4.8 GJ/tCO2. The economic analysis indicated a CAPEX between 6.7 and 7.6 MUS$/year and an OPEX between 19 and 20 MUS$/year, resulting in capture costs ranging from 81 to 88 US$/tCO2. The results confirm the technical feasibility of the process and the superior economic performance of MEA under the evaluated conditions.