Studies On Catalytic Pyrolysis In Confined Fluidized Bed

With the development the chemical industry, Petro-chemical industry and other light industry, the demand for propylene, which is the most important organic chemical feedstock, increases very quickly. In this case, all kinds of propylene production technology are developing rapidly. The Catalytic Cracking Process and appropriate catalyst with the character of strong adaptability, mild operating conditions, are widely attended in the production of propylene at home and abroad. Confined fluidized bed reactor with low cost, high thermal efficiency, the isothermal bed temperature, the low operation and maintenance cost, is widely applied in the research of heavy oil refinery technology.Aimed at the catalytic pyrolysis having the characteristics of high temperature and large quantity of gaseous product, a confined fluidized bed experimental unit was designed and built. And through the experiments of cold-model, it shows that this kind of reactor is suitable for the research of catalytic pyrolysis. According to the comparison of test results of the new unit and the old one, it can meet the precision requirements. Moreover the temperature can be above 700℃, which can offer the high temperature circumstance demanded by catalytic pyrolysis, and overcome the shortcoming of temperature below 600℃offered by the old unit. The gas is collected by water displacement, and the resistant can be largely minished by extending the pipe diameter. The test results show that the unit has high operation feasibility.With the feed of Daqing AR, the pyrolysis performance of three kinds of catalysts ZC-7300, LTB-2 and LCC-200 was studied on the Confined fluidized bed experimental unit. With the maximizing light olefins catalyst LCC-200, the influence of the temperature, C/O, W/O, and space velocity on heavy oil catalytic pyrolysis yield distribution were studied in this article. The results showed that the LCC-200 catalyst could increase the yield of olefins. For this catalyst, under the optimized operation conditions of reaction temperature at 620℃, cat-to-oil ratio of 4, water-to-oil ratio of 0.1 and space velocity 10 h-1, the total yield of light olefins can reach 35 percent.In the same condition, the experimental results under the confined fluidized bed and the riser reactors were compared, and the affecting factor of differences was analyzed. The confined fluidized bed has the characteristic of fluidized bed, and the reaction results of the two kinds of reactors have a lot of similarity. So it is convenient to develop the new technology of catalytic cracking/pyrolysis, to evaluate property of feed and catalyst with the confined fluidized bed.