Integrated Process of Monoethanolamine-Based CO<sub>2</sub> Absorption and CO<sub>2</sub> Mineralization with SFGD Slag: Process Simulation and Life-Cycle Assessment of CO<sub>2</sub> Emission
Zhi Yan, Yan Wang, Hairong Yue, Changjun Liu, Shan Zhong, Kui Ma, Wenjie Liao, Siyang Tang, Bin Liang
Abstract
Integrated CO2 absorption and mineralization (IAM) is a promising approach to fix CO2 in a far less energy-intensive way. The semidry flue gas desulfurization (SFGD) slag containing a considerable amount of Ca(OH)2 is potential for mineralizing CO2. In this work, an IAM process combining monoethanolamine (MEA)-based CO2 absorption and mineralization with SFGD slag is proposed and investigated to provide a systematical evaluation of the net CO2 fixation. A desorption efficiency of 68% and an entrainment efficiency of 32 wt % were experimentally determined. An entire IAM process model with a design specification of 8350 N m3/h flue gas feeding and a CO2 fixation efficiency of 90% is simulated using Aspen Plus software. Net CO2 fixation efficiency is analyzed through life-cycle assessment (LCA). A direct relationship between parameters and LCA of CO2 emission is built based on parameter sensitivity analysis. The IAM process, achieving the goal of gaseous waste treatment with solid waste, shows significant environmental benefits in reducing CO2 emission. MEA loss is the major contributor to CO2 emission, and energy consumption follows. A net CO2 fixation efficiency of 87.6% can be obtained with the optimized parameters. Reducing MEA loss would be effective to increase net CO2 fixation efficiency of the whole process. This work provides a quantitative understanding of CO2 fixation of the IAM process for industrial application and a guideline for further process optimization.