Experimental And Simulation Study On Mass Transfer Of Natural Gas Decarburization By Amine Method In The θ Ring Packed Column

For the natural gas pretreatment process,the amine decarbonization process using amine solution to absorb CO₂ in the packed column is currently widely used.In the purification process,gas-liquid mass transfer is mainly carried out on the surface of the column packing.The effective mass transfer area provided by the packing will directly affect the removal effect.At the same time,the performance of the amine absorbent as the basis of the process is equally important.Therefore,the research on the decarbonization and mass transfer process of the amine solution in the packed absorption column under high pressure is of great significance for optimizing operating parameters,improving processing capacity,and saving energy and reducing consumption.Based on the self-built 3mmθmesh ring packing absorption column,this paper conducts in-depth research on the process of natural gas decarbonization and mass transfer by experiment and numerical simulation.Through chemical absorption method,the effective mass transfer area a _V value of the filler under different influencing factors is obtained and its changing law is explored.The results show that:a _V increases with the increase of absorption pressure,but the growth trend is slow under high pressure（≥1MPa）;a _Vincreases first and then decreases with the increase of absorption temperature,but the value change range is small;a _V varies with the solution flow rate Increase and increase rapidly;gas flow has little effect on a _V;a _V increases with the increase of solution viscosity.Then use the amine absorbent with the formula36%wt.MDEA+4%wt.PZ+60%wt.H₂O to absorb CO₂/N₂ mixed gas under high pressure to simulate the decarburization process of natural gas,and the effects of different factors on the mass transfer performance of amine solution absorbing CO₂ were analyzed through experimental indicators such as the total volume mass transfer coefficient of gas phase K_Ga _V/total gas mass transfer coefficient K_ya _V,the removal rateηof packed column system and the temperature field of the packed column.The results show that the mass transfer performance increases with the increase of absorption pressure;With the increase of absorption temperature,the mass transfer performance first increases and then decreases,and the temperature field has obvious step temperature rise;With the increase of liquid flow rate,the mass transfer effect is obviously enhanced;With the increase of gas flow rate,the gas-liquid mass transfer performance increased,but the removal effect became worse.Finally,based on the two-film theory,a numerical model for predicting the mass transfer process using the self-built packed absorption column as a physical model is established,and the accuracy of the model under high pressure is corrected by introducing a pressure correction factor F.This model can be used to predict the CO₂ concentration and temperature distribution in the packed column.