Processes for dehydrogenation of a hydrocarbon feedstock are described. The process can be run at lower H.sub.2/HC ratios and lower RITs while maintaining coke production at the same level as operation at higher H.sub.2/HC ratios and higher RITs without decreasing the yield per pass. Acceptable levels of coke were achieved when operating the process at low hydrogen to hydrocarbon molar ratio in the range of 0.01 to 0.40 and reactor inlet temperatures in the range of 500?-645? C. The process uses a low coke catalyst.

Large pill dehydrogenation catalysts and large screens slot width are combined in dehydrogenation units to reduce the pressure drop across the catalyst bed and reactor screens compared to conventional screen and catalyst size combinations. The catalyst has an average pill diameter in the range of 1.6 mm to 3.0 mm, and the slot width of the screen is in the range of about 30% to about 60% of the pill diameter.

Processes for regenerating an at least partially deactivated catalyst that can include a Group (10) element, an inorganic support, and a contaminant. The Group (10) element can have a concentration of from 0.001 wt % to 6 wt %, based on the weight of the inorganic support. The process can include (I) heating the deactivated catalyst using a heating gas mixture that includes H.sub.2O at a concentration >5 mol %, based on the total moles in the mixture to produce a precursor catalyst. The process can also include (II) providing an oxidative gas that includes ?5 mol % of H.sub.2O, based on the total moles in the oxidative gas, and (III) contacting the precursor catalyst at an oxidizing temperature with the oxidative gas for a duration of at least 30 seconds to produce an oxidized precursor catalyst. The process can also include (IV) obtaining a regenerated catalyst from the oxidized precursor catalyst.

This disclosure relates to processes, compositions, and systems useful for the oxydehydrogenation of alkanes to form olefins (e.g., for the conversion of ethane to ethylene). The processes use an oxygen transfer agent and may be carried out in any suitable reactor, including a reverse flow reactor, a circulating fluid bed reactor, or a cyclic co-flow reactor.

The invention discloses a binder-free high strength and low steam-to-oil ratio ethylbenzene dehydrogenation catalyst, which is characterized by comprising the following components in percentage by weight: (a) 60-85% Fe.sub.2O.sub.3; (b) 3-25% K.sub.2O; (c) 0.1-5% MoO.sub.3; (d) 3-20% CeO.sub.2; (e) 0.1-5% CaO; (f) 0.1-5% Na.sub.2O; (g) 0.1-5% MnO.sub.2, wherein the weight ratio of sodium oxide to manganese dioxide is 0.1-10; (h) 0.1-100 ppm of at least one element or oxide of Pb, Pt, Pd, Ag, Au, Sn; and no binder is added during the preparation of the catalyst. The low steam-to-oil ratio ethylbenzene dehydrogenation catalyst provided by the present invention contains no binder and maintains high strength, and has high activity and stability at low steam-to-oil ratio.

Catalyst compositions and processes for making and using same. The catalyst composition can include catalyst particles. The catalyst particles can include 0.001 wt % to 6 wt % of Pt and up to 10 wt % of a promoter that can include Sn, Cu, Au, Ag, Ga, or a combination thereof, or a mixture thereof disposed on a support. The support can include at least 0.5 wt % of a Group 2 element. All weight percent values are based on the weight of the support. The catalyst particles can have a median particle size in a range from 10 ?m to 500 pm. The catalyst particles can have an apparent loose bulk density in a range from 0.3 g/cm.sup.3 to 2 g/cm.sup.3, as measured according to ASTM D7481-18 modified with a 10, 25, or 50 mL graduated cylinder instead of a 100 or 250 mL graduated cylinder.

Processes for converting an alkane to an alkene. In some embodiments, the process can include contacting a hydrocarbon-containing feed with a first catalyst that can include Pt or a second catalyst that can include Cr within a conversion zone to effect dehydrogenation of at least a portion of the hydrocarbon-containing feed to produce an effluent that can include one or more dehydrogenated hydrocarbons and molecular hydrogen. The process can also include contacting the effluent with a solid oxygen carrier disposed within the conversion zone to effect combustion of at least a portion of the molecular hydrogen to produce a conversion product that can include the one or more dehydrogenated hydrocarbons and water. In some embodiments, contacting the feed with the first or second catalyst can occur in a first conversion zone and contacting the effluent with the solid oxygen carrier can occur in a second conversion zone.

Processes for upgrading a hydrocarbon. The process can include introducing, contacting, and halting introduction of a hydrocarbon-containing feed into a reaction zone. The feed can be contacted with a catalyst within the reaction zone to effect dehydrogenation, dehydroaromatization, and/or dehydrocyclization of the feed to produce a coked catalyst and an effluent. The process can include introducing, contacting, and halting introduction of an oxidant into the reaction zone. The oxidant can be contacted with the coked catalyst to effect combustion of the coke to produce a regenerated catalyst. The process can include introducing, contacting, and halting introduction of a reducing gas into the reaction zone. The reduction gas can be contacted with the regenerated catalyst to produce a regenerated and reduced catalyst. The process can include introducing and contacting an additional quantity of the feed with the regenerated and reduced catalyst to produce a re-coked catalyst and additional first effluent.

The present invention relates to a stabilized rhenium-based heterogeneous catalyst, obtainable by a process comprising contacting a rhenium-based heterogeneous catalyst with a stabilizing agent at a temperature in a range from 0-100 C., the stabilizing agent comprising an aliphatic hydrocarbon compound and use thereof.

A method for producing a conjugated diene according to one aspect of the present invention comprises a step of contacting a raw material gas containing an alkane with a first catalyst and a second catalyst in this order to obtain a product gas containing a conjugated diene. In the production method, the first catalyst contains Sn and Pt, and a content of Sn in the first catalyst is less than 12% by mass based on the total mass of the first catalyst; and the second catalyst contains Sn and Pt, and a content of Sn in the second catalyst is 12% by mass or more based on the total mass of the second catalyst.