Conversion of methanol to gasoline
AssigneeMobil Oil Corporation
InventorsSusan K. Marsh, Hartley Owen, Bernard S. Wright
Life of this patent
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Abstract
A methanol-to-gasoline (MTG type) conversion process in which the conversion is conducted in a fixed bed catalytic reactor. A C.sub.3 -C.sub.4 hydrocarbon diluent is generated from the effluent in a series of steps and recycled to the fixed bed reactor in order to dissipate the heat of reaction.
Claims13
A continuous process for converting C.sub.1 to C.sub.3 oxygenated hydrocarbon feedstock to gasoline boiling range hydrocarbons in a fixed bed adiabatic reaction zone with a crystalline acid zeolite catalyst at elevated temperature and pressure comprising:
- charging oxygenate feedstock to said fixed bed reaction zone under conditions to convert substantially all oxygenates;
- cooling reaction effluent from said fixed bed reaction zone to form an aqueous liquid phase, a gas phase rich in C.sub.2.sup.- hydrocarbons, and a liquid phase rich in C.sub.3 + hydrocarbons;
- separating at a pressure below the reactor pressure the effluent into an aqueous stream, a gaseous stream, and a condensed C.sub.3 + liquid hydrocarbon stream;
- pumping the condensed liquid stream to a pressure above reaction zone pressure;
- passing said pumped hydrocarbon to a heat exchange evaporation zone;
- partially vaporizing said pumped hydrocarbon stream to form a vapor phase rich in C.sub.3 -C.sub.4 hydrocarbons and a liquid phase rich in gasoline product;
- separating said partially vaporized stream into a liquid product and a C.sub.3 -C.sub.4 rich vapor recycle stream;
- heating said recycle stream to reaction temperature;
- mixing said vapor recycle stream with oxygenate feedstock;
- and
- passing the feedstock-recycle mixture to said fixed bed catalytic reaction zone at reaction temperature whereby the temperature rise resulting from the large heat of reaction is moderated by the recycled C.sub.3 -C.sub.4 hydrocarbon vapor.
In the continuous process for converting methanol and/or dimethylether feedstock to gasoline boiling range hydrocarbons in the presence of a diluent vapor in a fixed bed adiabatic reaction zone with a crystalline ZSM-5 zeolite catalyst wherein cooled reactor effluent is separated into a byproduct water stream, light hydrocarbon gas stream, and a condensed liquid hydrocarbon stream, the improvement comprising:
- maintaining an effluent phase separation zone under conditions of pressure and temperature to recover a byproduct water phase, a withdrawn by product vapor phase rich in C.sub.2.sup.- hydrocarbons and a condensed liquid hydrocarbon phase comprising a major amount of C.sub.3.sup.+ hydrocarbons;
- pumping the condensed liquid phase above reaction zone process pressure and heating the condensed liquid stream to vaporize a major amount of C.sub.3 -C.sub.4 hydrocarbons to provide a recycle diluent stream comprising C.sub.3 -C.sub.4 hydrocarbons and a liquid gasoline product stream;
- and
- reheating the C.sub.3 -C.sub.4 recycle diluent stream for combining with feedstock and introducing the feedstock-diluent mixture to the reaction zone at elevated temperature and process pressure.
A continuous process for converting oxygenated hydrocarbon feedstock containing methanol, dimethyl ether or mixtures thereof to gasoline boiling range hydrocarbons in a fixed bed adiabatic reaction zone with a medium pore crystalline acid zeolite catalyst at elevated temperature and pressure comprising:
- contacting oxygenate feedstock with said catalyst in said fixed bed reaction zone in the presence of C.sub.3 -C.sub.4 saturated hydrocarbons under conditions to convert substantially all oxygenates and a portion of said saturated hydrocarbons to produce gasoline range hydrocarbons;
- cooling reaction effluent from said fixed bed reaction zone to form an aqueous liquid phase, a gas phase rich in C.sub.2.sup.- hydrocarbons, and a liquid hydrocarbon phase rich in C.sub.3 + hydrocarbons;
- separating at a pressure below reaction zone pressure the effluent into a byproduct aqueous stream, a byproduct gaseous stream, and a condensed C.sub.3 + liquid hydrocarbon stream;
- pumping the condensed liquid stream to a pressure above reaction zone pressure;
- heating and partially vaporizing said pressurized hydrocarbon stream to form a vapor phase rich in C.sub.3 -C.sub.4 saturated hydrocarbons and a first liquid product stream rich in gasoline product;
- separating said partially vaporized stream into a second liquid product stream and a C.sub.3 -C.sub.4 rich vapor recycle stream;
- heating and mixing said vapor recycle stream with oxygenate feedstock;
- and
- passing the feedstock-recycle mixture to said fixed bed catalytic reaction zone at reaction temperature and pressure whereby adiabatic temperature rise resulting from heat of reaction is moderated by the recycled C.sub.3 -C.sub.4 hydrocarbon vapor.
Dependencies are inferred from the claim text.