A Research On The Preparation Technology Of Thin-film Catalysts Used For Methanol To Olefins

Low-carbon olefins (ethene, propene) are important compounds on chemical engineering platform as well as the most useful chemical materials. Methanol to olefins (MTO) technology provides a new method to produce basic organic chemical materials from coals or natural gas. Now, it is one of the most possible ways to substitute the traditional method which produces olefins from oils. Meanwhile, it is also an effective way to extend coal chemical industry to petrochemical industry. So, it is very important to study the MTO catalysts and MTO technology in modern chemical engineering area.In this paper, MTO thin-film catalysts are prepared by the layer-separated growth method in fluidized-bed spray granulation technology. Molding process are also analyzed in this paper. The layer-separated growth process is separated into three stages including colliding stage, spreading stage and drying stage. The influencing factors such as concentration of the fluid, flux of the fluid, temperature of the bed, position of nozzle, excess gas speed and the flux of atomization air are analyzed based on the coating growth of the MTO thin-film catalysts and the amount of active components on the surface of the catalyst. The results turn out that within limits, if the concentration of fluid is higher, the flux of the fluid is faster, the position of nozzle is lower, the temperature of the fluidized-bed is lower, the excess gas speed is smaller and the flux of atomization air is smaller, it will be better for the growth of the catalyst coating. But, there is a critical point of the operation condition. It will effect coating growth and the amount of active components on the surface negatively or even lead to experiment failure.According to the analysis of the surface and cross section of the thin-film catalysts it is found that SAPO-34molecular sieve are located on the surface or coating of the catalysts. This method avoids the crazing on the surface of the catalysts. Based on the method of ASTM D5757～2000used for powder catalyst abrasion and characterization standard, MTO thin-film catalysts meet the requirement. By studying the property of the MTO thin-film catalysts, it turns out that MTO thin-film catalysts have the advantages of high conversion, high selectivity, long lifetime, high utilization. So, MTO thin-film catalyst is a good project to study.