Enhanced SO2 and CO2 synergistic capture with reduced NH3 emissions using multi-stage solvent circulation process

• Proposed a novel process for SO 2 and CO 2 synergistic capture using NH 3 /K 2 CO 3. • Enhanced SO 2 and NH 3 removal by circulating desulfurization-washing solution. • Obtained SO 2 capture efficiency greater than 99 % and NH 3 emissions less than 5 ppm. • Achieved a regeneration energy consumption of 2.42 GJ/t CO 2. NH 3 -based SO 2 and CO 2 synergistic capture technology shows promise in reducing the costs associated with current flue gas desulfurization and CO 2 capture systems. However, it faces challenges such as NH 3 slip and high energy consumption. In this study, we proposed an advanced Multi-Stage Solvent Circulation (MSC) process that incorporates a desulfurization-washing solution circulation, which involved partitioned absorption according to different functions of SO 2 capture, CO 2 capture, and NH 3 emission control. The experimental results demonstrated that using desulfurization solution in place of water for washing reduced the NH 3 emissions from the absorber and desorber by 10.6 % and 7.9 %, respectively. Additionally, the recovered NH 3 enhanced SO 2 capture, resulting in a 61.8 % decrease in SO 2 emission concentration. A pilot-plant trial model for SO 2 and CO 2 synergistic capture was further developed using Aspen Plus. The impact of operational time and parameters on capture efficiency and energy consumption were analyzed. Under typical flue gas conditions, the process achieved SO 2 capture efficiency of > 99 %, regeneration energy consumption of 2.42 GJ/t CO 2 , NH 3 emissions of < 5 ppm. This study presents a novel approach for designing a SO 2 and CO 2 synergistic capture system, which has the potential to facilitate the economic and effective implementation of post-combustion flue gas pollutant control management and carbon emission reduction.