炭膜的二氧化碳吸附扩散性能的研究

The CO_2 Absorption and Diffusion Performances of Carbon Membrane

以商业化的Kapton型聚酰亚胺为前驱体制备炭膜,采用容量法研究了不同炭化温度制备的炭膜CO2吸附和扩散行为,并利用Sips模型对实验数据进行拟合,DA方程计算炭膜的孔结构参数,Fick扩散模型求取CO2在炭膜内的扩散系数,采用XRD分析探讨了炭膜的炭结构。结果表明,炭膜孔结构随着热解炭化温度的提高,孔径收缩,且当炭化温度从600℃升高到800℃,炭膜的微孔体积随炭化温度的升高而增大,而800℃以后,微孔体积随炭化温度的升高而下降。CO2在不同炭膜中的扩散系数约为1.04×10-13~8.56×10-12m2·s-1,在实验测定的压力范围内扩散系数随着平衡压力的增大呈现出先增大后减小的规律。

Carbon membranes were prepared from the precursor of Kapton-type polyimide under different carbonization temperatures.The CO2adsorption and diffusion performance of the prepared carbon membrane were measured by means of volumetric method,where the adsorption data obtained were fitted by Sips model and the pore structure parameters of carbon membranes were calculated by DA equation.Fick diffusion model was used to calculate the CO2 diffusion coefficients in carbon membrane.Results indicate that the pore structures of carbon membranes are affected by the carbonization temperature.The pore sizes of carbon membrane are reduced as the carbonization temperature rises.The pore volume of carbon membrane is enlarged with the increase of carbonization temperature from 600 to 800℃ and decreased when the temperature is higher than 800℃.The CO2diffusion coefficients in the carbon membranes prepared at different carbonization temperatures are from 1.04×10-13m2·s-1 to 8.56×10-12 m2·s-1.Within the given pressure range in this work,the diffusion coefficient increases at first and then decreases as the equilibrium pressure rises.