THE PARTIAL OXIDATION OF CH4 TO CH3OH AT HIGH PRESSURE IN A PACKED REACTOR

In a considered effort to improve turbulence and heat transfer while reducing reactant/product residence time (enhancing primary product preservation) in the partial oxidation of methane lo methanol, a glass lined reactor was packed successively with a scries of metal (beads), glass (beads) and carbon ("solid foam"). The metal surfaces included, nickel, copper, silver, line, tin and stainless steel. The surfaces were assessed in terms of the methanol selectivity determined in the conversion of methane to methanol, for each packing. The surfaces were found to favour methanol selectivity in the following order: glass (70%) > stainless steel (67%) > silver (64%) > nickel (63%) = zinc (63%) = tin (62%) > carbon (30%) > copper (0%). Copper promoted the direct and complete oxidation of methane to CO 2 and H 2 O. No appreciable advantage other than improved heat transfer was found using the metal beads. Apparently the increased surface area of the beads had a negative effect on the methanol yield, since the highest methanol selectivity in this study was obtained for the empty glass lined reactor (74%). In an additional study alternatives to the glass lined reactor were considered including stainless steel, carbon steel (Al06) and the corresponding Alonized steel. Carbon steel (66%) was found to be about as effective as stainless steel (70%) in terms of methanol selectivity though not as effective as glass (74%). Alonized steel (Al06) (40%) had an adverse effect on the methanol yield since its surface catalysed the dehydration of methanol to dimethyl ether (10%). Alonized stainless steel also produced dimethyl ether (3%) though less methanol was lost in Ms way (66%).