| Zeolites have been widely used as catalysts, adsorbents and exchangersin chemical and petroleum industries due to their particular structure andproperties. It is very important to understand the adsorption of adsorbates invarious zeolites. In this paper, molecular simulation techniques was used tosimulate the adsoption and separation of alkanes/alkenes and their mixtures indifferent zeolites.Firstly, the zeolite-gust systems to be investigated in this study have beenset up and the corresponding parameters have been obtained. The simulatedisosteric heat of adsorption was in good agreement with the experiment datareported in literatures. Based on these facts, we got some results as follows:1.The saturated adsorption quantity of propene in MFI zeolites decrease as thetemperature increases at different temperatures;2. The selectivities of thezeolites for propene in the propane-propene mixtures is in order ofMOR>MFI>TON (with mole fraction of0.5for propane in gas phase);3. Forternary mixture，the adsorption isotherms in MOR zeolite show that the longerchain component is preferentially adsorbed at low pressures. The adsorptionquantity of propane increases the maximum and then decreases as thepressure increases. But for the shorter chain component, it is adsorbed athigher pressures and its adsorption increases as the pressure increases.Secondly, frameworks of NanZSM-5type zeolites with various Si/Alrations have been constructed. Then, the adsorption of propane and propeneon NanZSM-5with various Si/Al rations have been investigated and Henry`slaw constants, adsorption isotherms, potential sites of adsorption and theaverage potential energy were predicted. The dual-site Langmuir model wasapplied to simulate the adsorption of propane and propene in NanZSM-5typezeolites.The results show that Si/Al ratio of zeolite framework affects thepropane adsorption little, but the saturated adsorption of propene decreases as the Si/Al ratio was increasing. |
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