Study On Adsorption Separation Of Ethylene/Ethane In Refinery Dry Gas

Ethylene was an important chemical raw material and refinery dry gas was rich in it. Separation of ethylene/ethane from dry gas could effectively improve the processing capability of ethylene plant and economic benefits. Adsorption separation was a good process due to its low energy consumption and less economic input. This dissertation first compared the adsorption performances of different adsorbents for ethylene/ethane separation and optimized the preparation conditions and adsorption process conditions. The adsorption rate dynamics model of ethylene was also established.Results demonstrated that compared with the nut and coal activated carbons, coconut shell charcoal(CSC) was the suitable carrier of complexation adsorbent. The separation performance of CuCl2/CSC for ethylene/ethane was superior to that of AgNO3/VCSC and CuCl/CSC. Modern characterization results showed that high temperature activation could spread and reduct CuCl2on CSC. The optimal preparation and adsorption conditions of CuCl2/CSC were as follows:the optimum loading amount of CuCl2was36.7%(wt%), the optimum calcination temperature was400℃, adsorption temperature was40℃, feed gas flow was40mL/min. Dynamic adsorption capacity of ethylene on36.7%CuCl2/CSC reached23.55mg/g and ethylene/ethane separation factor reached7.6under latm. CuCl2/CSC had good regenerative properties, while existence of water and oxygen degraded the results of adsorption effects. Lagergren second-order kinetic equation fitted the adsorption rate of ethylene well and the adsorption isotherms of ethylene on CuCl2/CSC belonged to the preferential adsorption.In addition, the study of adsorption separation of ethylene/ethane on zeolite5A was made. The adsorption capacity of ethylene on zeolite5A reached33mg/g and the separation factor of ethylene/ethane reached4.5under latm,40℃. The decrease of adsorption temperature and the increase of adsorption pressure both contributed to the separation effects. AgNO3/5A adsorbent had obvious improvement of ethylene/ethane separation factor, but the adsorption capacity of ethylene significantly reduced.