Investigation of Key Factors and Their Interactions in MTO Reaction by Statistical Design of Experiments

Abstract

Abstract The effects of templating agent [i. e., tetraethyl ammonium hydroxide (TEAOH), triethylamine (TEA) and morpholine (MOR)] and molar ratio of SiO2/Al2O3 and H2O/Al2O3 over SAPO-34 catalysts in methanol to olefin (MTO) reaction were studied systematically. The exact effect of main factors and their interaction were studied by response surface methodology (RSM) applying central composite design (CCD). Two empirical models for two systems, based on these preparation variables for the yield of ethylene and propylene were constructed in two CCD studies and ultimately these models showed as counter and three-dimensional (3D) diagrams. Analysis of Variance (ANOVA) applied for investigating the significance of the variables indicated that TEA and SiO2/Al2O3 content were the most significant variables in the case (1) and case (2), respectively. The maximum predicted ethylene and propylene yield was 58.57 wt. % and 30.22 wt. %, for catalyst with TEA = 0.2, TEAOH = 0.38 in case (1). For case (2), catalyst with SiO2/Al2O3 = 0.17, H2O/Al2O3 = 101.18 showed the maximum ethylene and propylene yield of 49.87 wt. % and 20.58 wt. %, respectively.