Effect of Mn and Ni Concentration on Synthesis of Nanostructured MnNiAPSO-34 Catalyst Used in Conversion of Methanol to Light Olefins

Nanostructured molecular sieve، SAPO-34 exhibits the best performance in the production of light olefins. Furthermore، due to the importance of MTO process، various researches have been conducted to improve SAPO-34 properties. Therefore، studying catalyst synthesis could be effective in controlling its structure and improving its properties. Using various metals like transition metals، could enhance catalyst acidity by creating new acid sites and resultantly increasing the catalyst lifetime. So، the present research is focused on the incorporation of Mn and Ni modifiers with different concentrations in synthesis of SAPO-34 zeolites to enhance the catalyst properties. MeAPSO-34s (Mn0. 05Ni0. 1APSO-34 and Mn0. 1Ni0. 05APSO-34) were synthesized by hydrothermal method using DEA as template and their catalytic properties and activities were investigated. The catalysts were characterized by XRD، FESEM، EDX، BET and FTIR techniques and catalytic performance tests were carried out toward MTO reaction. The results of XRD and FESEM for Mn0. 05Ni0. 1APSO-34 and Mn0. 1Ni0. 05APSO-34 catalysts showed a crystal size of 44. 5 and 47. 2 nm and particle size of 15 and 12. 2 μm، respectively. The BET analysis indicated large specific surface area for the catalyst synthesized with high concentration of Mn. The catalytic performance of the synthesized catalysts in MTO reaction showed that methanol conversion of all samples were 100% in the studied range of temperatures. Moreover، Mn0. 1Ni0. 05APSO-34 catalyst with respect to catalyst stability and activity is much better than Mn0. 05Ni0. 1APSO-34. The selectivity of light olefins for this catalyst with high specific surface area was 78% after 6 h time on stream.