| Propylene is one of the major raw materials used in organic synthesis. Global consumption of propylene upgrades significantly. In our country, a large surplus of C4 is used as low-value fuel. Research about catalytic pyrolysis process of C4 for producing propylene has concentrated more and more attention now. Therefore, studies and application of the catalytic pyrolysis rules of C4 hydrocarbons are great significant.The experiments were mainly carried out in the mixed flow reactor (MFR). At first, flow pattern was tested for ensuring that the gas flow follow fully mixed pattern in actual experiment condition. The experiment results show that the gas flow pattern in the reactor can reach mixed flow situation in actual experiment condition. The product distribution and reaction discipline was investigated respectively choosing C4 and isobutene as raw materials on the lab-made ZSM-5 zeolite catalyst. The equilibrium compositions of C2~C6 olefins were investigated, and were compared with the calculation results.During the experiment conditions, when the engine speed is 3000r/min and WHSV is 1.50~3.75h-1, the gas follows the mixed flow pattern, besides, the reactor is uniformly heated, hence there is no concentration gradient and temperature gradient. When using the C4 as the material, the conversion of C4 is high to about 80%. When the temperature is 530℃, WHSV is 3h-1, both the selectivity and yield of propylene are highest, and the yield can reach 29.41%. When using the isobutene as the material, the reaction abiding by the same mechanism that polymerization then cracking, and the optimum condition is that the temperature is 580℃and WHSV is 2.25h-1. The variation tendency as the temperature of equilibrium composition of the product distribution of catalytic pyrolysis of isobutene is basically consistent with the variation of the calculated values. Only considering thermodynamic factors in the circumstances, the best temperature of C4 catalytic pyrolysis to produce propylene is 600℃.
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