Process for the production of methane containing gases

Abstract

Abstract A PROCESS FOR THE PRODUCTION OF A GAS CONTAINING A HIGH PROPORTION OF METHANE (E.G. 90% OR MORE) COMPRISES: (I) INTRODUCING A PREHEATED MIXTURE OF STEAM AND THE VAPOUR OF A PREDOMINANTLY PARAFFINIC HYDROCARBON FEEDSTOCK HAVING A FINAL BOILING POINT OF NOT MORE THAN 300*C. (E.G. NAPHTHA) INTO A FIRST CATALYTIC REACTION ZONE IN WHICH THE MIXTURE REACTS IN THE PRESENCE OF A STEAM REFORMING CATALYST TO GIVE A GAS CONTAINING METHANE, HYDROGEN, CARBON OXIDES AND UNDECOMPOSED STEAM; (II) COOLING THE GAS PRODUCED IN STAGE (I) BY ADDING A FURTHER QUANTITY OF AT LEAST ONE OF THE REACTANTS; (III) INTRODUCING THE GASEOUS MIXTURE FORMED IN STAGE (II) INTO A SECOND CATALYTIC REACTION ZONE IN WHICH THE CONSTITUENTS OF THE MIXTURE REACT IN THE PRESENCE OF A CATALYST TO INCREASE THE PROPORTION OF METHANE IN THE MIXTURE; AND (IV) REMOVING STEAM AND CARBON DIOXIDE FROM THE GAS LEAVING THE SECOND CATALYTIC REACTION ZONE. THE GAS MAY BE USED AS A SYNTHETIC NATURAL GAS. IN BOTH STAGES (I) AND (III) THE TEMPERATURE IS KEPT AS LOW AS POSSIBLE, DEPENDING ON THE CATALYST: FOR EXAMPLE, STAGE (I) MAY BE OPERATED AT A CATALYST BED TEMPERATURE OF 400-500*C., AND STAGE (III) SUCH THAT THE OUTLET TEMPERATURE IS 200-250*C., WHEN A LOW TEMPERATURE STEAM REFORMING CATALYST IS USED IN BOTH STAGES. THE REACTION ZONE IN STAGE (III) MAY BE INTERNALLY COOLED, AT LEAST AT THE OUTLET END OF THE ZONE. THE COOLING IN STAGE (II) IS PREFERABLY ACHIEVED BY ADDING COLD HYDROCARBON FEEDSTOCK.

Inventors

• 👤 Brian Hoyle Thompson

Bibliographic Details