Study On The Performance Of NCC-1 Catalyst For Producing More Propylene And Ethylene In Catalytic Cracking

NCC-1 catalyst is a new type of catalytic cracking catalyst developed on the basis of Y/ZSM-5 composite molecular sieve.Previous studies of Y/ZSM-5 zeolite always focused on the catalytic performance and reaction mechanism.Few articles reported the stability of the catalyst prepared from this type of zeolite.Therefore,it is urgent and necessary to study the stability and the capacity in catalytic cracking of Y/ZSM-5zeolite catalyst.In this paper,the decay of NCC-1 catalyst's activity was studied on the basis of ZDT-1 riser FCC pilot plant.The crystal structure,acidity,particle size and catalytic performance of NCC-1 catalyst were mainly observed.The results show that when using mixed wax oil as raw material the,crystal inity of the catalyst can reach and stabilize 89%of the fresh catalyst in 100 h under the experimental conditions of 500? reactor temperature,700? regenerator temperature,2.80 s residence time and 8.0catalyst-oil ratio.At the same time,the total acid content of the catalyst will decrease from 0.064 mmol/g to 0.051 mmol/g.The granularity has not changed much.The yield of liquefied gas in the product decreased from 44.37%to 34.70%,and the conversion of raw materials decreased from 85%to 77%.In this paper,we try to further optimize the catalytic performance of NCC-1catalyst by changing the experimental conditions.The results show that when the reaction temperature rises from 500? to 580?,the conversion of feed oil increases from 76.6%to 85.6%,and the yield of liquefied gas increases from 35.8%to 37.6%.After the residence time increased from 2.47 s to 3.81 s,the conversion of feed oil increased from 60.10%to 67.14%,and the yield of liquefied gas increased from 32.29%to 40.56%.In terms of physicochemical properties of the catalyst,the specific surface area of NCC-1 catalyst is similar to that of USY catalyst and USY catalyst with propylene additive.The acidity is between them,and the particle size distribution and wear index are similar.Compared with USY catalyst and USY catalyst with propylene promoter,the conversion of mixed wax oil on NCC-1 catalyst is 16%and 13%lower,respectively.However,the yields of ethylene and propylene are 2.54%and 16.46%,which can be increased by about 1%and 4%respectively compared with the other two catalysts..In summary,although the catalytic activity of NCC-1 catalyst is lower than that of traditional catalytic cracking catalyst.But the yield and selectivity of ethylene and propylene in the product are higher.NCC-1 catalyst is more suitable for the current trend of pursuing high value-added products in chemical industry.