Comparison of Water- and Amine-Based Carbon Capture Processes for Air and Oxyfuel Combustion Technologies

Carbon capture, utilization, and storage (CCUS) technologies can efficiently contribute to the mitigation of greenhouse gas emissions. Carbon capture with pressurized water is applied in the ammonia plant, and it has recently gained significant attention due to its environmentally friendly features. In this study, the technoeconomic evaluation of the water-based carbon capture system is carried out and compared with the alternative using aqueous MEA solution. The flue gas originates from a gas-fired power plant. Two options are considered: (i) an air-combustion system and (ii) an oxyfuel combustion system. The calculated results show that in both air and oxyfuel-combustion technologies, the power consumption of the H2O–CO2 capture method exceeds that of the MEA–CO2 capture method by approximately 30% and 45%, respectively. This considerable difference notably increases the operational costs of the power plant. However, by the application of gas dehydration before the H2O–CO2 capture technique, the power consumption and the cost of water-based carbon capture can be significantly decreased. Although such an improvement makes the water-based carbon capture system the least energy consuming alternative, it requires mainly electricity and still has higher utility costs compared to MEA-based alternatives.