Techno-Economic Analysis of a Hybrid System for Flue-Gas Separation: Combining Membrane and Enzymatic-Absorption Processes

摘要

Fossil-fuel power plants supply a large part of global energy for domestic and industrial applications at the expense of releasing a high volume of carbon dioxide (CO2) in the atmosphere. The gas separation market is currently dominated by amine-based absorption technology, which is costly, energy-intensive, and less ecofriendly. Herein, a hybrid system including membrane and enzymatic-absorption processes is proposed to remove CO2 in flue-gas emitted from a 600 MWe power plant. As the above-mentioned standalone processes suffer from high investment cost and energy consumption, the hybrid process would exhibit better performance through sharing partial CO2 capture between two separation units. The optimization results reveal that the membrane process becomes economically more efficient through removing CO2 in bulk by 75% from the flue-gas. The complete CO2 capture through the enzymatic-absorption unit then allows to remarkably reduce solvent circulation rate between absorption and desorption units, as well as the energy of CO2 regeneration. Overall, the hybrid process contributes to decrease the total electricity loss by 124 MW and the total annual cost by 139 M $, which are 10 and 37% lower than those in the standalone membrane process, respectively.