Analysis Of Energy Consumption Characters In MEA And Ammonia Based Carbon Capture And Optimization Of System

Greenhouse effect caused by CO₂ emission makes people clearer and clearer about the harms of CO₂ emissions, particularly in fossil fueled power plant. Carbon Capture and Storage is thought to be the most effective method to reduce CO₂ emissions in short term. Wet process post-combustion carbon capture represented by MEA based carbon capture with a long history is thought to be the most mature and applicable. But a large amount of steams must be extracted from the power plant to meet the energy need of the MEA based carbon capture system. In order to apply this technique in real power plant, the parameters of carbon capture system must be optimized, the energy consumption of the stripper and the cost of the carbon capture power plant must be reduced. Here, a model of the MEA based carbon capture system was established with the help of Aspen Plus, a variable condition model of a coal fired power plant and the technical economic evaluation model of the carbon capture power plant were established. The influence of CO₂ load in lean MEA solution, concentration of MEA solution, pressure in the stripper and lean solvent temperature and carbon capture rate on the performance of MEA based carbon capture system and carbon capture plant were analyzed. Then the optimum parameters of the carbon capture system were selected.MEA solution was expensive and can be easily degraded in the mixer of O2 and CO₂. With strong corrosive, MEA only can be used after dilution. Much energy will be consumed in the carbon capture system and the output of the power plant will be strongly reduced. MEA based carbon capture system was blocked by the shortcomings put above. Ammonia based carbon capture system can reduce the energy consumption, doesn't have corrosive problems, it was cheap and didn't produce organic products, so there is vast application prospect for it. An ammonia based carbon capture system-Chilled Ammonia Process?short for CAP? was established with the help of Aspen Plus. The coupling method of the CAP and the power plant were proposed and selected. The influence of the main parameters?ammonia concentration, CO₂ load in the lean solution, inlet temperature of the absorber and pressure of the stripper? of the carbon capture system on the performance of the carbon capture system and carbon capture plant were analyzed. Then the feasible parameters of the CAP system were selected.CAP is much complexer than MEA based carbon capture process. First, CAP must add refrigeration equipments; second, ammonia capture system must be added to reduce the slip of ammonia and last CAP needs two steam extractions so the system is complicated. Under the optimized parameters, the energy consumption of the CO₂ capture system was 0.85GJ/?tCO₂? and the energy consumption of the ammonia capture system was 1.89GJ/?tCO₂?. They were much smaller than that in MEA based carbon capture?3.96GJ/?tCO₂??. But 0.09GJ/?tCO₂? refrigerate power must be added. All in all, power generation efficiency of the power plant with CAP can be 0.40% higher, coal consumption can be 3.89g/kWh lower, net output can be 28.93 MW higher than that of MEA based carbon capture power plant. From technical economical analysis, the initiate investment of the CAP based carbon capture power plant was 21.20% higher than that of MEA based carbon capture power plant. The power generation cost of the MEA based carbon capture power plant is 0.020?/kWh higher and carbon capture cost is 31.21?/?tCO₂? higher than that of CAP based carbon capture power plant. So, the energy and technical economic performance of the CAP based carbon capture power plant was better than that of MEA based carbon capture power plant.