摘要
采用体积法在273K和303K温度下对CO2、CH4和N2在不同硅/铝比的β沸石上的吸附分离性能进行了研究。实验结果表明,Langmuir-Freundlich模型能够较好地拟合吸附实验数据;同一样品上,CO2的吸附量要大于CH4和N2的吸附量;随着硅铝比的减小CO2的吸附量增加,而硅/铝比对CH4和N2的吸附量的影响较小。通过结合Virial方程计算CO2、CH4和N2在不同硅/铝比β沸石上的亨利定律常数和吸附选择性,发现所研究样品对CO2/CH4和CO2/N2均具有很高的吸附选择性,随着样品硅/铝比的减小,CO2/CH4和CO2/N2的吸附选择性显著增加,说明较低硅/铝比β沸石有利于分离CO2。用Clausius-Clapeyron方程求得CO2、CH4和N2在不同硅/铝比的β沸石上的吸附热与吸附量无关,表明β沸石是一种表面势场均匀的吸附剂。
The adsorption separation of CO2, CH4 and N2 was studied via volumetric measurements of β-zeolite samples with different SIO2/Al2o3 ratios at 273 and 303 K. Results showed that all the obtained adsorption isotherms are well correlated with the Langmuir-Freundlich model. For a certain sample, the adsorption capacity for CO2 is much higher than that for CH4 and N2. The adsorption capacity for CO2 increases with the decrease in SIO2/A1203 ratio under same temperature and pressure. The Henry law＇s constant and adsorption equilibrium selectivity of CO2, CH4, and N2 on different β-zeolite samples were calculated via Virial equation, showing that the β-zeolite samples have higher equilibrium selectivity for CO2 over N2 and CH4. The selectivity of CO2 over N2 and CH4 increases with the decrease in SIO2/A1203 ratio. Therefore, the β-zeolite sample with a low SiO2/Al203 ratio is a good candidate for the separation of carbon dioxide from its mixture with methane and nitrogen. The isosteric adsorption heat for CO2, CH4 and N2 calculated by Clausius-Clapeyron equation is independent with the increase of adsorption loading, which indicates that β -zeolite is an energetically homogenous adsorbent
出处
《化工进展》
EI
CAS
CSCD
北大核心
2009年第12期2116-2121,共6页
Chemical Industry and Engineering Progress
基金
江苏省高校自然科学重大基础研究项目(08KJA530001)
长江学者和创新团队发展计划项目(IRT0732)
关键词
二氧化碳
Β沸石
硅/铝比
吸附
分离
CO2
β-zeolite
SIO2/A1203 ratio
adsorption
separation
