Study On The Purification Of C5 Alkane Containing Alkene By Adsorption Method

Olefin/paraffin separations represent a class of the most important as well as most expensive separations in the chemical and petrochemical industry, especially for ethylene/ethane separation. Cryogenic distillation has been used for many years for these separations from olefin plants; even so it remains the most energy-intensive process because of the close relative volatilities of the components. The large energy and capital investment requirement provides the incentive for ongoing of olefin/paraffin separation technology research. So a number of alternatives have been investigated. The most promising one appears to be separation viaπcomplexation.In this paper, current situation of adsorption separation via complexation in industry application and complexation adsorbent research were summarized. At the same time, adsorption mechanism and preparation of new adsorbents with high adsorption selectivety of 3-methyl-1-butene were studied respectively, so did both adsorption equilibrium of the prepared sorbent and behavior of adsorption on fixed bed. All of these studies established a solid foundation of application in industry scale that the new process of olefin and paraffin's separation had lower economizes on energy. In this paper, the zeolites have been prepared for adsorption by cation exchange method in solution. The removal effects of 3-methyl-1-butene from isopentane in a fixed-bed microreactor by deficient zeolite adsorbents were investigated. The purifying effects of technology parameters during the adsorption process have been studied extensively. The main contents are as follows:AgA, AgY and AgMOR zeolite adsorbents have been prepared by cation exchange method in solution. A series of characterization methods, such as XRD, TG and water adsorption capacity, have been employed to evaluate the as-prepared adsorbents. After cation exchange, the crystallinity of AgA zeolite decreases, and it could not be promised adsorbents.By using fixed-bed, the adsorption properties of AgMOR and AgY zeolites to 3-methyl-1-butene have been investigated.AgMOR zeolite has a low adsorption capacity to the adsorbate. Under the conditions of 20℃, 1 atm, and material gas flow rate 40 mL/min, AgMOR zeolite could adsorb 0.84 mg 3-methyl-1-butene per gram. However, AgY zeolite could be a good adsorbent for 3-methyl-1-butene in isopentane. The adsorbed quantity is 115 mg/g under the condition of 20℃, 1 atm and material gas flow rate 40 mL/min. After adsorption, the mass percentage of 3-methyl-1-butene in isopentane drops from 600 ppm to 30 ppm.In the fixed-bed experiments, The effects of the adsorption temperature, bed height and gas flow rate on the adsorption breakthrough curve, adsorption capacity, LUB (equivalent length of unused bed) and Q (utilization rate of bed) were also discussed. It is shown that as the temperature rising, the adsorption quantity of 3-methyl-1-butene lowers down. We set 20℃as the appropriate temperature for removing 3-methyl-1-butene from pentane. The adsorption capacity is unrelated to the bed height, and the raising of the material gas flow rate is not propitious to the separation of 3-methyl-1-butene/pentane. The length of unused bed (LUB) was concerned to the gas flow rate but not to the bed height. The zeolite adsorbents can produce purified gas when the bed height was larger than LUB. The AgY adsorbents can be regenerated and reused for eighteen times.