Process to convert synthesis gas to olefins over a bifunctional chromium oxide/zinc oxide-SAPO-34 catalyst

A process for preparing a mixture of lower hydrocarbons, comprising

• (A) introducing a feedstream into a reactor,
• the feedstream comprising hydrogen gas and carbon monoxide gas, such that the volumetric ratio of hydrogen to carbon monoxide ranges from greater than 0.5:1 to less than 3:1;
• and
• (B) contacting the feedstream and a bifunctional catalyst in the reactor,
• the bifunctional catalyst having not been reduced prior to the contacting,
• the bifunctional catalyst comprising as components
• (1) chromium oxide/zinc oxide mixed metal oxides and
• (2) a SAPO-34 silicoaluminophosphate molecular sieve;
• under reaction conditions sufficient to form a product mixture,
• the reaction conditions comprising
• (a) a reactor temperature ranging from greater than 300 degrees Celsius to less than 450 degrees Celsius;
• (b) a pressure ranging from greater than 0.2 megapascals to less than 5.0 megapascals;
• the product mixture comprising, as calculated on a hydrogen-free, carbon monoxide-free, and carbon dioxide-free basis
• (c) a combined ethylene and propylene content greater than 30 percent by weight;
• (d) a combined ethane and propane content less than 50 weight percent;
• (e) a methane content less than 15 weight percent;
• (f) a combined saturated and unsaturated C4 and higher hydrocarbon content less than 20 weight percent;
• and
• (g) an oxygenates content less than 5 weight percent;
• each weight percentage being based upon total product mixture weight and,
• when taken together, equaling 100 weight percent.