Thesis (M.Sc.)--Chulalongkorn University, 2002

Ni-SAPO-34 and Ni-SAPO-44 catalysts with Si/Ni ratios of 40 and 80 were synthesized. In this study, tetraethylammonium hydroxide and cyclohexylamine were used as template in preparation of Ni-SAPO-34 and Ni-SAPO-44, respectively. Effects of template/P2O5 and Si/Ni ratios on formation of the catalysts were studied. The catalysts were characterized using XRD, XRF, ICP-AE, SEM, NH3-TPD and nitrogen adsorption techniques. The catalysts were tested for their activities in methanol conversion to olefins. Various parameters including time on stream, temperatures (300-500 ํC) and Si/Ni ratios affect the methanol conversion and product selectivity. It was found that, using a feed of 22% methanol in nitrogen at a gas hourly space velocity (GHSV) of 2000 h-1, the methanol conversion on Ni-SAPO-34 catalyst (Si/Al = 40) at 450 ํC is 100%. Only little coke formation is observed and the content of methane gas is low. Decrease of nickel content leads to higher selectivity to light olefins, principally ethylene, and less coke deposition in the catalysts. The degree of coke formation is quite low compared to other types of catalyst.