Research On Performances Of Scale-up Catalyst For Methanol To Olefins

Methanol to olefins process based on coal or natural gas is considered to be the most attractive process to take place of petroleum route process. Research on the catalyst for methanol to olefins is of importance for the methanol to olefins process technology development. And in the process of industrialization of catalyst, investigation of catalyst scale-up preparation is an important stage as well as an essential stage. The paper gives some results about the performances of SAPO-34 molecular sieve catalyst prepared in the test device over methanol to olefins reaction.SAPO-34 molecular sieves are synthesized in autoclave being of lm3 and used as the catalyst for methanol to olefins reaction in the lab's reaction-regeneration fluidized bed with dimensions ofΦ30mm×320mm for its dense section andΦ68mm×160mm for its thin section. The effects of reaction temperature, space velocity (WHSV) and feed composition on molar fraction of ethylene and propylene are investigated. Meanwhile, the deactivated catalyst is regenerated in the fluidized bed and then the catalytic performances of the regenerated catalyst is studied to decide the optimal temperature and time of the regeneration. Also, the catalyst SAPO-34 and the regenerated catalyst are characterized by means of XRD, SEM, N2 isothermal adsorption/desorption, NH3-TDP, respectively.The results indicate that, under optimal conditions for proceeding operation methanol to olefins:i. e. temperature of 475℃, WHSV of 2.5h-1 and feed methanol composition of 90wt%, the total molar fraction of ethylene and propylene among the products can reach 90.3% which is very close to the molar fraction while the MTO reaction was catalyzed by the lab catalyst SAPO-34, and the regenerated catalyst performs as well as the fresh one when regenerated at 600℃for 90min. Also, the catalyst SAPO-34 and the regenerated catalyst were characterized by means of XRD, SEM, N2 isothermal adsorption/desorption, NH3-TPD. It comes out that, the microstructure and the distribution of the strong and weak acid site have no evident changes. The study shows that pilot-scale SAPO-34 catalyst acts as well as laboratorial SAPO-34 catalyst.