Study On Technology Of Butane Catalytic Dehydrogenation For Butene With Fixed-Fluidized

Every year, a large quantity of C4hydrocarbons came from refining companies in China.However, light olefin with a lot of butane, which is remained after alkene extraction is sold asa fuel. This approach leads to low utilization，low added-value of C4hydrocarbons and awaste of resources.For example, butenes from butane catalytic dehydrogenation will be usedin other product if light olefin is further processed; it will improve the utilization and added-value of light olefin. Butane catalytic dehydrogenation for butene started in the1950’s andwas applied to the industrialization in the1970’s in the world. In China, this study began in1980’s or1990’s and continues to today, but it is still in the laboratorial scale. Currently, thisresearch is developed by Lanzhou Petrochemical Research Center and Lanzhou Institute ofChemical Physics.Two kinds of catalysts, noble metal catalysts and non-noble metal catalysts, are used inthe process of butane catalytic dehydrogenation for butene. Noble metal catalysts include Ptsystem, Rh system, Ir system, Pd system, and so on. However, Pd system catalyst is onlyapplied to the industry. Non-noble metal catalysts include Cr system, V system, Fe system,Mo system, Zn system, and so on, but the Cr system catalyst is tremendously used in industry.The mainstream technologies of butane catalytic dehydrogenation for butene in the worldinclude Oleflex technology comes from UOP company, Catofin technology comes fromLummus company, Star technology comes from Phillips company, FBD-4technology comesfrom Snamprogetti company, Linde technology comes from Linde company. However, thereis no independent technology about butane catalytic dehydrogenation for butene in Chinanowadays, and some technologies applied to the industry at home come from foreigncompanies.Therefore, the research on butane catalytic dehydrogenation for butene issignificant for no longer dependence on foreign multinationls.The process conditions of butane catalytic dehydrogenation for butene which was usedCr system catalyst (LICP-1) from Lanzhou Institute of Chemical Physics in fixed-flow bedreactor are studied in this paper. The test shows that LICP-1catalyst exhibits the differentconversion of butane ranging65~75%and selectivity of butene ranging80~81%in the pureisobutane at reaction temperature610℃, within1hour, airspeed of750h-1. Compared with the pure isobutane, LICP-1catalyst shows higher butenes selectivity of2~5%in refinery gasat reaction temperature590℃and airspeed of750h-1. The experiment indicates that catalystactivity increases slightly and the coking rate accelerates greatly with the increase oftemperature by comparing different temperature of590℃,600℃,610℃,620℃.In this paper, the thermodynamics process of butane catalytic dehydrogenation forbutene is analysed. The calculating formulas of r H m(T), r S m(T), r G m (T)are deduced.Each process of butane catalytic dehydrogenation for butene is calculated with these formulas.The comprehensive result shows that isobutene can be generated directly,1-butene is firstlygenerated by n-butane, and then isobutene, cri-butene, trans-butene are obtained byisomerization of1-butene.The different process conditions are studied in this paper, including catalyst fillingquantity, the amount of the carrier, the content ofisobutane, input quantity, the reactiontemperature, catalyst regeneration in the fixed-flow bed reactor with mixed C4hydrocarbonfrom Lanzhou petrochemical company as raw material. The study shows that the conversionof butane reaches about45%, selectivity of butenes as high as80%, the yield of butene wereabout45%when the catalyst filling quantity of252g, feed rate for150g/h, atmosphericpressure, the reaction temperature for610℃, the flow rate of N2for3L/min. The test findsthat LICP-1catalyst is poisoned by steam. The activity of toxic catalyst can regenerate afterroasting under700℃with air. The reactivity of Cr system catalyst is also studied in thispaper. The conversion of butane, the selectivity of butenes, the yield of the regeneratedcatalyst are the same as the fresh catalystat under the same reaction conditions. At the sametime, the result of regeneration shows that the activity of catalyst would not significantlyreduce for many times. Finally, the valuable information that butane catalyticdehydrogenation for butenes with LICP-1catalyst is obtained in this paper.