Improvement of SAPO-34 performance in MTO reaction by utilizing mixed-template catalyst synthesis method

Abstract

In the present study, the silicoaluminophosphate (SAPO-34) molecular sieves were synthesized by one of tetraethyl ammonium hydroxide (TEAOH) or morpholine structure-directing agents (SDAs) as the single-template and their mixture as the mixed-template methods. The effects of different types and combinations of templates on the structure and morphology of SAPO-34 molecular sieves were investigated by XRD, SEM and BET techniques. The catalytic performance of the synthesized SAPO-34's were investigated in a fixed-bed reactor for methanol to olefin (MTO) reaction. In comparison to single-template SAPO's, mixed-template catalyst possessed larger surface area, smaller particle size and exhibited higher selectivity to light olefins (C2=–C4=) and longer lifetime.