Numerical Simulation Of MEA-based CO₂ Absorption In A Spray Column

Spray column are a very important part of power plant CO2 capture systems.Due to the complexity of the layout of the spray pipe of spray column that absorb CO2 by the MEA method in coal-fired power plants,the distribution uniformity of the smoke is low and the absorption efficiency is not high.Therefore,this paper studies the structure of the spray column to improve the distribution performance of the spray liquid in the spray column,the distribution performance of the flue gas in the spray column,and then increase the CO2 absorption rate in the flue gas,and the CO2 capture efficiency of the power plant.Improvement has implications.Spray nozzles,spray layer layout scheme,number of spray column inlets,smoke distributors,etc.were designed.FLUENT was used for numerical simulation,and then general-purpose finite-rate simulation was used to simulate CO2 absorption in MEA solution.in conclusion:1)The effect of uniform gas distribution on absorption efficiency is very large,close to a linear relationship.Through structural design and simulation analysis,it was found that the four-inlet porous ring spray column have higher distribution uniformity and lower pressure drop;2)According to the principle of large flow rate of atomizing nozzle size design,with 0.1240 kg / s as the inlet flow rate,after the atomization of droplets Socket particle diameter D32 is 118,the atomization angle of 87.6 °.0.1240 kg/s,0.1395 kg/s,0.1550 kg/s,and 0.1735 kg/s nozzle inlet flow rates were taken respectively.Numerical simulation under the same boundary conditions showed that the atomization cone angle increased with the increase of flow rate.Particle diameters continue to decrease.According to the number of nozzles in each layer and the position of nozzle installation,four different nozzle layout schemes are determined;3)Combining the component transport equations and chemical reaction mechanism,the kinetic data of the pre-exponential factor A and reaction activation energy E of the MEA solution absorbing CO2 reaction were obtained.Using FLUENT software to simulate the effects of the number of single-layer nozzles,single nozzle flow rate,smoke inlet velocity,and liquid-gas ratio on absorption efficiency under the same conditions,it can be found that: With the number of nozzles in the spray column With the increase,the absorption efficiency increases first,and then there is a small decrease.The layout scheme when the number of nozzles is 16 is considered as the optimal spray layout scheme;as the single nozzle flow rate increases,the absorption rate of CO2 absorption rate increases rapidly first and then increases.Slower speed;With the increase of the speed of the flue gas inlet,the absorption efficiency decreases;With the increase of the liquid-gas ratio,the absorption rate also increases.When the single-nozzle liquid-gas ratio reaches 0.4096L/m3,the absorption efficiency tends to increase,the absorption efficiency tends to a stable value in the end.