| The amount of CO2 from power plants accounts for roughly 30 percent of the total CO2 emmission. Therefore researching and optimizing CO2 capture from flue gas from power plants of low cost and large scale are of great significance. The existing carbon capture technology has a great disadvantage of high energy consumption. Aimed at decreasing energy consumption, optimization and improvement of CO2 capture system which will concentrate CO2 40,000t/a is researched based on PRO/Ⅱsimulation platform. Using chemical method, pure MEA and MEA+MDEA blend amines are researched in the paper. The research provides the reference and guidance of CO2 capture from flue gas of power plants for industry use, for the purpose of reducing the cost, decreasing the energy consumption and increasing the yield of CO2.CO2 absorption model of chemical method is established. The influences of key factors (volume flow rate of absorption solution, temperature of absorption solution, temperature of flue gas, concentration of absorbent etc.) on CO2 absorption rate are analyzed. CO2 loadings at various trays are compared. The influence of MEA concentration of blend amines solution on CO2 absorption rate is discussed. And prompting effect on CO2 absorption rate is inquired when the pressure of absorber increased. Absorption process parameters are acquired through simulation.The results show that 40℃is the proper temperature of absorption solution and flue gas. And adding a small amout MEA to MDEA solution greatly prompts the CO2 absorption.CO2 desorption model of chemical method is established.The influences of key factors (reboiler heat duty, pressure of reboiler etc.) on CO2 desorption rate are analyzed. The influence of reboiler pressure on the temperature of outlet lean amine is investigated. Temperatures of regenerator at various trays are compared. And prompting effect on CO2 desorption rate is inquired when the pressure of regenerator decreased. The results show that the optimizing reboiler heat duty is 7000kw, and the optimizing pressure of reboiler is 120kpa when using MEA absorption.The optimizing reboiler heat duty is 5000kw～5500kw, and the optimizing pressure of reboiler is 90kpa when using MEA+MDEA absorbent.Carbon capture technology is improved in the process flow by adding a pipe. Recycling stream of absorbent solution is bring to the absorption process. The minimum volume flow rate is reduced in the improved process flow. As a result, reboiler heat duty is decreased. The results of simulation show that the yield of CO2 is increased 5.0%～14.3% and reboiler heat duty decreased 7.5%～8.1% by adopting the modified process flow compared with the typical process flow. |
