A process for preparing C.sub.2 to C.sub.4 hydrocarbons includes introducing a feed stream into a reaction zone of a reactor, the feed stream comprising hydrogen gas and carbon monoxide. An additional stream is introduced into the reaction zone of the reactor, the additional stream comprising carbon dioxide. A combined stream that includes the feed stream and the additional stream is converted into a product stream comprising C.sub.2 to C.sub.4 hydrocarbons in the reaction zone in the presence of a hybrid catalyst. The hybrid catalyst includes a mixed metal oxide catalyst component, and a microporous catalyst component. The process operates at a gas hourly space velocity in excess of 2500 hr.sup.-1 and effectively yields a net carbon dioxide selectivity of less than 5.0% and a productivity of C.sub.2-C.sub.4 hydrocarbons greater than 75 g hydrocarbons per kilogram of catalyst per hour.

A process for preparing C2 to C3 hydrocarbons may include introducing a feed stream including hydrogen gas and a carbon-containing gas comprising carbon monoxide, carbon dioxide, and mixtures thereof into a reaction zone of a reactor, and converting the feed stream into a product stream comprising C2 to C3 hydrocarbons in the reaction zone in the presence of a hybrid catalyst. The hybrid catalyst may include a metal oxide catalyst component and a microporous catalyst component comprising 8-MR pore openings less than or equal to 5.1 A and a cage defining ring size less than or equal to 7.45 A, where a C2/C3 carbon molar ratio of the product stream is greater than or equal to 0.7.

The present invention features a direct synthesis of light olefins through the hydrogenation of carbon dioxide. In.sub.2O.sub.3 supported on cubic phase yttria-stabilized zirconia is used as a catalyst and is mixed with a molecular sieve to perform the hydrogenation. The cubic crystal structure of the yttria-stabilized zirconium dioxide is an excellent support for indium oxide particles and prevents their deactivation during CO.sub.2 hydrogenation. This direct synthesis route promotes a stable and efficient method for producing light olefins.

Catalysts and catalytic methods are provided. The catalysts and methods are useful in a variety of catalytic reactions, for example, the oxidative coupling of methane.

A process for preventing hazardous conditions at startup and shutdown of a reactor by sending an inert gas such as nitrogen to strip entrained oxygen from the catalyst when reactor temperatures are below about 240° C. During normal operation the entrained oxygen reacts with hydrocarbons to produce oxides but at the lower temperatures that are present at startup or shutdown these reactions do not occur sufficiently leaving oxygen that can cause hazardous conditions as temperatures increase upon startup. When the temperature is in the safe operating zone above 240° C., the nitrogen gas is stripped by air or other oxygen containing gas.

According to one or more embodiments, a method for forming light olefins may comprise introducing a hydrocarbon feed stream into a reactor, reacting the hydrocarbon feed stream with a dehydrogenation catalyst in the reactor to form a high temperature dehydrogenated product, separating at least a portion of the dehydrogenation catalyst from the high temperature dehydrogenated product in a primary separation device, combining the high temperature dehydrogenation product with a quench stream to cool the high temperature dehydrogenation product and form an intermediate temperature dehydrogenation product, and cooling the intermediate temperature dehydrogenation product to form a cooled dehydrogenation product.

A process for oxidative dehydrogenation of a hydrocarbon to produce an olefin and water may include contacting, in a fluidized bed, the hydrocarbon with a particulate material, which may include at least one oxygen transfer agent (OTA) and at least one fluidization enhancing additive. During at least a portion of contacting the hydrocarbon with the particulate material, the fluidized bed may be at a temperature at or above a melting point of one or more materials of the oxygen transfer agent. Further, during at least a portion of contacting the hydrocarbon with the particulate material, a surface of at least a portion of the OTA may comprise a molten layer. The fluidization enhancing additive may not undergo reduction in the fluidized bed during contacting the hydrocarbon with the particulate material and may be present in an amount that maintains sufficient fluidization of the particulate material.

According to one or more embodiments of the present disclosure, chemical streams may be processed by a method which may comprise operating a first chemical process, stopping the first chemical process and removing the first catalyst from the reactor, and operating a second chemical process. The reaction of the first chemical process may be a dehydrogenation reaction, a cracking reaction, a dehydration reaction, or a methanol-to-olefin reaction. The reaction of the second chemical process may be a dehydrogenation reaction, a cracking reaction, a dehydration reaction, or a methanol-to-olefin reaction. The first reaction and the second reaction may be different types of reactions.

The present invention relates to a process for the production of butadiene by condensation of ethanol using a catalyst containing sillica-supported elements from group 3A and group 4B of the periodic table. The catalyst of the present invention has high activity and selectivity to butadiene in the synthesis reaction of said olefin from ethanol.

A process for preparing C.sub.2 to C.sub.4 olefins includes introducing a feed stream of hydrogen gas and a carbon-containing gas into a reaction zone of a reactor and converting the feed stream into a product stream including C.sub.2 to C.sub.4 olefins in the reaction zone in the presence of a hybrid catalyst and in a non-oxidative atmosphere. The hybrid catalyst includes a metal oxide catalyst component comprising gallium oxide and zirconia, and a microporous catalyst component having an 8 membered ring structure. The process also includes periodically introducing an oxidative atmosphere into the reaction zone.