A Comparison Of Monoethanolamine And Chilled Ammonia CO₂Capture Technology

Chemical absorption is suggested as one of the possible, promising technologies forcapturing CO₂from industrial power plant. Among previous studies, most researchersconcern about the developing of high efficient and low energy consumes absorbents. In ourthesis, two kinds of sorbents （monoethanolamine and chilled ammonia） were employed anda comparison between their efficiency was taken.Firstly，a simulation model of ethanolamine based or chilled ammonia based carbondioxide capture system was established based on ASPEN simulation platform. The effect ofthe main operating parameters （temperature, pressure, lean load, absorbent concentration,etc.） to renewable heat consumption and absorption capacity was analyzed, and then got thebest optimized capture system operating parameters. Simulation results show that: Formonoethanolamine based CO₂capture system, the thermal energy requirement was3.71GJ/t CO₂, the power penalty was40.85kWh/t, and the absorption capacity was18.4m³solution/t CO₂. For chilled ammonia based CO₂capture system, the thermal energyrequirement was2.64GJ/t CO₂, the power penalty was127.66kWh/t, and the absorptioncapacity was4.24m³solution/t CO₂.Then, a300MW power plant simulation was carried out, obtained the informationsuch as thermodynamic parameters of major steams, for the preparation of the CO₂capturesystem integrated with power plant. By comparing the simulation results and the actualoperation data, verified the reliability of simulation results.Finally, we studied the integration characteristics of CO₂capture system with powerplant. The choice of steam extraction location was the main consideration point of CO₂capture system integrated with power plant，there was certain selection method to choosethe steam extraction location. Reasonable choice for the extraction location can maximizethe use of steam heat value, reduce the power plant efficiency losses. Formonoethanolamine based CO₂capture system, the power plant efficiency loss was11.3%,the amount of extracted steam demand was0.87kg steam/kg CO₂, and the CO₂emissionwas2.82mol CO₂/kWh with CO₂capture. For chilled ammonia based CO₂capture system, the power plant efficiency loss was10.4%, the amount of extracted steam demand was0.62kg steam/kg CO₂, and the CO₂emission was2.74mol CO₂/kWh with CO₂capture.A comprehensive comparison of two capture technologies showed that，with lowenergy penalty and high absorption capacity, the chilled ammonia based capture system wassuperior to the monoethanolamine based capture system.