Process Development On Hierarchical Gas-Phase Catalytic Cracking Of Crude Oil For Light Olefin Productions

With the gradual increase of the demand for light olefins and the vigorous development of new energy vehicles planned by various countries in the world today,the demand for clean energy has been increased,and the demand for fuel oil has been reduced,resulting in excess capacity of fuel oil,making the integration of chemical refining and chemical industry a hot issue.The process of producing ethylene and propylene by direct catalytic cracking of crude oil has always been the focus of research.However,due to the gradual heavy quality and inferior quality of crude oil,its high viscosity,serious coking and other problems are easy to cause catalyst deactivation,which makes it difficult to process crude oil.In order to reduce the yield of coke and increase the yield of light olefins,our team developed a fractioned gas phase catalytic cracking process to achieve the purpose of producing more light olefins by using a new reactor and a new reaction process.In Py-GC /MS,the application of direct catalytic Pyrolysis of crude oil is studied,and the appropriate reaction conditions are explored.The optimum reaction temperature of acid-base catalyst is 630℃,and the yield of light olefins is 33.7%.The optimum reaction temperature of calcium aluminate catalyst is 700℃,and the yield of light olefins is 21.55%.The optimum reaction temperature of ZSM-5 catalyst is 600℃,and the yield of light olefins is 31.33%.The pilot scale experiment of direct catalytic cracking of crude oil was carried out in a self-mixing downcast bed to explore the best reaction conditions.The optimum reaction temperatures of ZSM-5,acid-base composite catalyst and calcium aluminate catalyst are 590℃,610℃ and 620℃,respectively.The yields of low olefin at the optimum reaction temperatures are 42.04%,40.8% and 38.76%,respectively.The acid-base composite catalyst is the best catalyst.In order to improve the yield of light olefins,the basic research on fraction-gas catalytic cracking of crude oil was carried out in Py-GC /MS.The optimal reaction temperature of acidbase composite catalyst was 610℃,and the yield of light olefins was 46.2%.The optimum reaction temperature of ZSM-5 as gas phase catalyst is 590℃,and the yield of low olefin is42.09%.The production of low olefin from crude oil was scaled up in pilot scale.The raw material was pretreated with calcium aluminate catalyst at 550℃,and the optimal reaction temperature of acid-base composite catalyst as gas phase catalyst was 590℃.The yield of low olefin was46.22%,propylene was 22.86%,and coke was 2.1%.When ZSM-5 was used as gas phase catalyst,the optimal reaction temperature was 590℃,and the yield of low olefins,propylene and coke was 44.31%,21.52% and 4.58% respectively.The acid-base composite catalyst has better effect when used as gas phase catalyst.Compared with the pilot-scale results of the hierarchical gas-phase catalytic cracking process and the direct catalytic dehydrogenation cracking process,under the same optimal reaction conditions,Compared with the direct catalytic cracking process,the methane yield,total low olefins yield,light oil yield and optimum reaction temperature decreased by 6.3%,5.42%,5.98% and 5.98% respectively.