In the recent years demand for light olefins has been increased. Due to increasing of crude oil price, production of this component from naphtha is not economical. Methanol to olefins process has been attracted due to utilization of methanol which was produced from coal, biomass and especially natural gas. Our country has huge sources of natural gas and application of methanol to olefins process provides a new route for proper utilization of these sources. SAPO-34 catalyst is a nanostructure molecular sieve from SAPO family and is known as the best catalyst for methanol to olefins process because of small pore size and medium acidity. Fast deactivation is the main problem of this catalyst. Morphology and particle size has the most important role in activity and lifetime. Accordingly, using of appropriate synthesis methods for production of small particles and nanometric structure of SAPO-34 catalyst seems to be required. Incorporation of metal into the catalyst structure could increase the catalyst lifetime and reduce methane formation. Generally, molecular sieves were synthesized employing conventional hydrothermal method. In this research, nanostructured SAPO-34 based catalysts were synthesized by a new high temperature hydrothermal method and were improved by Ce.

The effect of temperature and time on the synthesis of SAPO-34 and CeSAPO-34 has been investigated. All the synthesized catalysts were characterized by XRD, FESEM, FTIR and BET techniques. The XRD analysis confirmed formation of nanostructured crystalline structure of SAPO-34 catalyst in various syntheses temperature. AlPO4 zeolite as a competition phase could be produced in the samples with high temperature and long synthesis time. FESEM analysis showed the production of small spherical particle with uniform particle size distribution. The BET analysis indicated appropriate surface area for the all nanostructured catalysts. The FTIR analysis illustrated the formation of CHA phase and related bonds. In order to evaluate the performance of fabricated catalyst, the samples were used in a low pressure experimental setup of methanol to olefins conversion. This experimental setup has been designed and made in Reactor and Catalysis Research Center at Sahand University of Technology. Using high temperature hydrothermal method for synthesis of SAPO-34 catalyst led to reduce particle size and changed the morphology to sphericity which resulted of accumulation of cubic particles. Particle size was controlled between 600 nm to 3μm by applying high temperature hydrothermal method. Small particles with uniform size distribution had a long lifetime in the methanol to olefins process. Catalyst synthesized at temperature of 300°C and 3 h had longest stability in period of 20 h. The concentration of 0.5% of cerium oxide led to a significant increase in stability and reduction in methane formation.