气液膜接触器分离混合气中CO_2过程研究

建立了膜接触器吸收CO2 ,溶液热再生连续循环实验装置 ,评价了疏水性PP(聚丙烯 )微孔膜 ,MDEA(N 甲基二乙醇胺 )溶液及添加活化剂PZ(哌嗪 )的活化MDEA溶液吸收CO2 传质过程。结果表明 :在溶液浓度 2 5mol L ,气速0 5～ 3 0L min,液速 15～ 15 0mL min时 ,总传质系数Kov为 1 0× 10 - 5～ 3 6× 10 - 5m s(MDEA) ,1 6× 10 - 5～ 4 5×10 - 5m s(MDEA +PZ)。采用阻力层无因次关联方程模型预测Kov值 ,计算值和实验值符合较好。基于模型和实验结果 ,将PZ的吸收行为作为溶液的活化作用 ,在计算Kov值时 ,考虑活化作用因素并归结于化学增强因子E中 ,模型能更好地预测实验结果。实验证明在单一醇胺组份MDEA中添加少量PZ能提高总传质系数Kov值

SEPARATION OF CO2 FROM GAS MIXTURE IN GAS-LIQUID MEMBRANE CONTACTOR

The experimental setup for absorption of CO_2 with membrane contactor as absorber has been established.The absorbents composed of methyldiethanolamine (MDEA) aqueous solution or activated MDEA mixed with piperazine (PZ) aqueous solution were hot-regenerated in regenerator and were used continually and cycledly in the setup.Mass-transfer performances of absorption of CO_2 in PP microporous hollow fiber membrane contactor were studied.The results demonstrated that,under the conditions of 2 5 mol/L of amine concentration,the range of 0 5～(3 0 L/min) of gas flow-rate and the range of 15～150 ml/min of liquid flow-rate,the overall mass transfer coefficients K_(ov) of CO_2 absorption are about (1.0×10~(-5))～3.6×10~(-5) m/s for MDEA and 1.6×10~(-5)～4.5×10~(-5) m/s for MDEA+PZ.In addition,the value of K_(ov) was predicted by mathematical model of dimensionless resistances correlation equations.The results of prediction showed that the K_(ov) value of calculation was better accordant with experimental value.Based on the model and the results of experiments.effect of activation of PZ on absorption takes into account,and the factors of activiation are merged into enhancement factor E in calculation of K_(ov) value for activated aqucous solution.It is found that prediction values of the model were better agreed with experimental values.Meanwhile,the results of experiment concluded that the overall mass transfer coefficient K_(ov) is enhanced by means of adding activator PZ into MDEA aqueous solution.