ABSTRACT
There are two basic types of methanol synthesis catalysts. One is a high-temperature, high-pressure catalyst and the other is a low-temperature, low-pressure catalyst. In both the low-temperature and high-temperature catalysts, the ratio of copper to zinc or of zinc to chromium can be very sharply modified. Furthermore, copper as copper oxide can be added to the zinc chromite composition to give a copper-zinc-chromium so-called high-temperature, high-pressure catalyst, which under the influence of the added copper will now be suitable for operation at lower temperatures and pressures. The high-temperature, high-pressure methanol synthesis catalyst has a composition of Cr2O3•CuO•ZnO or Cr2O3, ZnO. Both contain chromium and for this reason cannot be used for landfill because the chromium oxidizes in the landfill environment to water-soluble Cr6+. Low-temperature methanol synthesis catalyst has a composition of CuO•ZnO•Al2O3 in various proportions. It also must be reduced before use and usually is dumped from a reactor in at least partially reduced condition.
