Simulation And Optimization Of Efficient Internals Of Flue Gas CO₂Capture Column Of Large-scale Power Plant

Chemical absorption method has been widely used in the flue gas CO2captureproject of the coal-fired power plant, but there are still some problems in thelarge-scale applications:1) The amplification effect of the column. The enlargementof the column causes the uneven distribution of the gas liquid, which lead to thereduction of the capture efficiency of the flue gas CO2。2) Mechanical problems ofthe large column. The design of the internals’ support structures and other problemsneed to be solved in the Large-scale column.This paper carried out the matching study of the amine solution and the captureequipment, and screened a kind of tower packing with high efficiency, highthroughput and low pressure drop. The author also studied the distributioncharacteristics of the gas distributor, the optimization of the support structure of thepacking truss, which can effectively reduce the operation cost of the capture device,reduce the amplification effect of the large-scale packing tower, and improve thestability of the capture device.Based on the actual process route of the flue gas CO2capture demonstrationproject of the power plant, the author designed and built the measurementexperiment platform of the desorption energy consumption of CO2capture withbatch chemical method, measured the absorption rate of MEA solution of variousconcentration, observed the changing rule that desorption rate is determined by time,and observed the coupling rule of the desorption energy consumption and thedesorption velocity of the alcohol amine and the desorption amount of CO2at thesame time. The author found that the increase of the amine solution concentration ishelpful to improve the absorption rate of CO2, and the desorption energy consumption of the15wt%of the MEAis the minimum.Flue gas CO2capture packed of the power plant can take both the squarereinforced concrete column and the circular steel column. From the aspects of thestructure, gas-liquid mass transfer and investment cost, the gas phase distribution ofthe circular column is slightly better than the square column, and the initialinvestment of the reinforced concrete tower is low. Use Aspen software to makesystematic analysis of the flue gas CO2capture engineering of the coal-fired powerplant, and overall considering the performance parameters, such as: packed towerdiameter, gas phase pressure drop, solution circulation volume, energy consumptionof the solution boiling and so on, the combination property of the Mellapak250X isbest, the minimum tower diameter is11.1m, and the packed height is16m.In the article, the author used the k-ε turbulent model of the FLUENT softwareto make numerical simulation of the flow field in the twin-tangential annular flowgas distributor under various widths of circular passage L and various amount of theguide plate N. The author found that the performance of the gas distributor is bestwhen the height of the tower is5m, the height of the distributor is4000mm, theamount of the baffles is14and the width of the circle passage is1800mm. Both thetwin-tangential annular flow gas distributor and the two-line vane gas distributor canmeet the requirements of the gas performance of the flue gas CO2capture column,the gas distribution performance of the twin-tangential annular flow gas distributor isbetter, while the pressure drop of the two-line vane gas distributor is lower.