用梯度硅藻土膜分离CO_2/N_2混合气

Separation of CO_2/N_2 mixture with gradient diatomaceous earth membrane

用梯度硅藻土膜管分离CO2 /N2 混合气 ,实验发现硅藻土膜对CO2 分子有亲合吸附作用 ,分离效果好 ,有高的分离因子 ,但渗透通量小。大的膜孔径和高的二氧化碳浓度不利于CO2 分子在硅藻土膜上的亲合吸附 ,分离效果不好 ,分离因子小 ,但有大的渗透通量。孔径沿径向由大到小逐渐梯度变化的膜结构能获得高的气体渗透通量和好的二氧化碳分离效果。合适的CO2 浓度范围为体积分数小于 15 % ,最佳气体渗透通量为 0 19mol/s/m2 。孔径 0 1μm的梯度硅藻土膜管有良好的CO2 分离性能 ,在通量 0 19mol/s/m2 ,原料气中CO2 含量为 10 %时 ,分离因子可达 4 3,CO2 的气体渗透速率为 3 2× 10 5mol/s/m2 /Pa。

The separation of CO 2/N 2 mixture using the gradient tubular membrane of diatomaceous earth was studied. It was found that the CO 2 molecule was adsorbed affinitively on the diatomaceous earth membrane. The diatomaceous earth membrane gave the high separation factor with low flux. The increasing of the pore size of the membrane or the concentration of the CO 2 resulted in the decreasing of the separation factor and increasing of the flux. The gradient diatomaceous earth membrane had special microstructure in which the pore size of the membrane was decreased gradually from large to small along radial. The high gas permeating flux and high separation factor can be obtained using this kind of gradient diatomaceous earth membrane. The suitable CO 2 concentration was lower than 15%(V). The separation factor of CO 2 and N 2 was 4 3 with the flux of 3 2 x10 5 mol·s 1 ·m 2 ·Pa 1 on the diatomaceous earth membrane of 0 1μm pore size under 10% CO 2 concentration.