In one aspect, the disclosure relates to a process for dehydrogenating a first dehydrogenation reactant into its unsaturated counterparts. The disclosed process comprises introducing a dehydrogenation reactant to a metal oxide catalyst having dehydrogenation activity, and dehydrogenating the dehydrogenation reactant to provide its unsaturated counterpart and hydrogen; selectively combusting the hydrogen released during dehydrogenation using a lattice oxygen from the metal oxide catalyst, resulting in a reduced metal oxide catalyst and steam; re-oxidizing the reduced metal oxide catalyst by introducing a gaseous oxidant to the reduced metal oxide catalyst; and optionally re-using the re-oxidized metal oxide catalyst for catalytic conversion and combustion. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

In one aspect, the disclosure relates to a process for dehydrogenating a first dehydrogenation reactant into its unsaturated counterparts. The disclosed process comprises introducing a dehydrogenation reactant to a metal oxide catalyst having dehydrogenation activity, and dehydrogenating the dehydrogenation reactant to provide its unsaturated counterpart and hydrogen; selectively combusting the hydrogen released during dehydrogenation using a lattice oxygen from the metal oxide catalyst, resulting in a reduced metal oxide catalyst and steam; re-oxidizing the reduced metal oxide catalyst by introducing a gaseous oxidant to the reduced metal oxide catalyst; and optionally re-using the re-oxidized metal oxide catalyst for catalytic conversion and combustion. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

Method for the preparation of a catalyst comprising vanadium pentoxide supported on a metal oxide catalyst carrier comprising the steps of a) providing particles of crystalline vanadium pentoxide and particles of a metal oxide catalyst carrier; b) solid state mixing the particles and dispersing the vanadium pentoxide particles on surface of the metal oxide carrier particles; and c) anchoring the dispersed vanadium pentoxide particles on surface of the metal oxide carrier particles by calcination at a temperature above 500 C., characterized in that sintering of the vanadium pentoxide particles is suppressed by addition of an anti-sintering metal oxide component, such as tungsten trioxide, during the anchoring in step c).

Method for the preparation of a catalyst comprising vanadium pentoxide supported on a metal oxide catalyst carrier comprising the steps of a) providing particles of crystalline vanadium pentoxide and particles of a metal oxide catalyst carrier; b) solid state mixing the particles and dispersing the vanadium pentoxide particles on surface of the metal oxide carrier particles; and c) anchoring the dispersed vanadium pentoxide particles on surface of the metal oxide carrier particles by calcination at a temperature above 500 C., characterized in that sintering of the vanadium pentoxide particles is suppressed by addition of an anti-sintering metal oxide component, such as tungsten trioxide, during the anchoring in step c).

A combustion system operated at low cost is provided. A combustion system 1 includes a combustion device 10 that burns fuel, an exhaust line L1 through which exhaust gas flows, the exhaust gas being generated through combustion of the fuel in the combustion device 10, a dust collector 50 that is disposed in the exhaust line L1 and that collects dust in the exhaust gas, and a denitration device 90 that is disposed in the exhaust line L1 and that removes nitrogen oxide from the exhaust gas using a denitration catalyst. The denitration device 90 is disposed downstream from the dust collector 50 in the exhaust line L1. The denitration catalyst contains 43 wt % or more of vanadium pentoxide and has a BET specific surface area of 30 m.sup.2/g or more.

A combustion system operated at low cost is provided. A combustion system 1 includes a combustion device 10 that burns fuel, an exhaust line L1 through which exhaust gas flows, the exhaust gas being generated through combustion of the fuel in the combustion device 10, a dust collector 50 that is disposed in the exhaust line L1 and that collects dust in the exhaust gas, and a denitration device 90 that is disposed in the exhaust line L1 and that removes nitrogen oxide from the exhaust gas using a denitration catalyst. The denitration device 90 is disposed downstream from the dust collector 50 in the exhaust line L1. The denitration catalyst contains 43 wt % or more of vanadium pentoxide and has a BET specific surface area of 30 m.sup.2/g or more.

A hydroprocessing catalyst or catalyst precursor has been developed. The catalyst is a transition metal molybdotungstate material or metal sulfides derived therefrom. The hydroprocessing using the transition metal molybdotungstate material may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.

The invention provides a catalyst enhanced MgAl-based hydrogen storage material, which is prepared by the following method: provide Mg and Al metal raw materials: weigh the Mg and Al metal raw materials according to a molar ratio of Mg: Al=(16-18): (11-13); perform the first vacuum melting on the Mg and Al metal raw materials; and crush the primary Mg alloy ingots to obtain the primary Mg alloy blocks; provide Ti, Zr and V metal raw materials weigh the primary Mg alloy blocks, and the Ti, Zr and V metal raw materials; perform ball milling treatment to obtain composite metal powder; press the composite metal powder into the loose alloy ingots; perform hot pressing treatment on the loose alloy ingots to obtain the dense alloy ingots, perform heat treatment on the dense alloy ingot; and wire cut the dense alloy ingots after heat treatment.

Described are SCR catalyst systems comprising a first SCR catalyst composition and a second SCR catalyst composition arranged in the system, the first SCR catalyst composition promoting higher N.sub.2 formation and lower N.sub.2O formation than the second SCR catalyst composition, and the second SCR catalyst composition having a different composition than the first SCR catalyst composition, the second SCR catalyst composition promoting lower N.sub.2 formation and higher N.sub.2O formation than the first SCR catalyst composition. The SCR catalyst systems are useful in methods and systems to catalyze the reduction of nitrogen oxides in the presence of a reductant.

Described are SCR catalyst systems comprising a first SCR catalyst composition and a second SCR catalyst composition arranged in the system, the first SCR catalyst composition promoting higher N.sub.2 formation and lower N.sub.2O formation than the second SCR catalyst composition, and the second SCR catalyst composition having a different composition than the first SCR catalyst composition, the second SCR catalyst composition promoting lower N.sub.2 formation and higher N.sub.2O formation than the first SCR catalyst composition. The SCR catalyst systems are useful in methods and systems to catalyze the reduction of nitrogen oxides in the presence of a reductant.