In a first stage of a methane conversion system, at least some methane (CH.sub.4) in an input gas flow stream can be converted into C.sub.2 hydrocarbons, hydrogen gas (H.sub.2), and aromatics to provide a first processed stream. The conversion can be direct non-oxidative methane conversion (DNMC). At least some of the aromatics can be removed from the first processed stream to provide a second processed stream. In a second stage of the methane conversion system, at least some of the H.sub.2 can be removed from the second processed stream to provide a recycle stream. The recycle stream can be returned to the first stage of the methane conversion system for further conversion of methane and removal of aromatics and H.sub.2 products.

In a first stage of a methane conversion system, at least some methane (CH.sub.4) in an input gas flow stream can be converted into C.sub.2 hydrocarbons, hydrogen gas (H.sub.2), and aromatics to provide a first processed stream. The conversion can be direct non-oxidative methane conversion (DNMC). At least some of the aromatics can be removed from the first processed stream to provide a second processed stream. In a second stage of the methane conversion system, at least some of the H.sub.2 can be removed from the second processed stream to provide a recycle stream. The recycle stream can be returned to the first stage of the methane conversion system for further conversion of methane and removal of aromatics and H.sub.2 products.

Process for the conversion of non-oxidative coupling of methane to ethylene, under non-oxidative conditions, comprising: providing a first stream containing at least 50 vol. % of methane based on the total volume of said first stream; providing a catalyst; putting in contact said first stream with said catalyst at a weight hour space velocity ranging from 0.5 to 100 h.sup.−1, a temperature ranging from 500° C. to 1100° C. and a pressure ranging from 0.1 MPa to 5 Mpa in the absence of oxygen; recovering a second stream containing unconverted methane if any, ethylene and hydrocarbons having at least 2 carbon atoms. Said process is remarkable in that said catalyst is a synthetic zeolite material, containing at least one metal M with silicon to metal M molar ratio Si/M as determined by inductively coupled plasma optical emission spectrometry ranging from 100 to 65440 and in that said metal M is incorporated inside of the zeolite tetrahedral sites.

The invention relates to a composition containing a catalyst having high catalytic stability for conducting oxidative coupling of methane (OCM) at high carbon efficiency, while improving both methane and oxygen conversion. Particularly, the inventive catalyst is a metal oxide supported catalyst, which contains an alkali metal promoter and a mixed metal oxide component having at least one alkali earth metal and at least one rare earth metal. The metal oxide support is selected in a manner, such that at least a portion of the metal oxide support is capable of reacting with at least a part or whole of the alkali metal promoter under conditions of calcination during catalyst preparation. The invention further provides a method for preparing such a metal oxide supported catalyst composition, using a calcination process. Additionally, the invention further describes a process for producing C.sub.2+ hydrocarbons, using such a catalyst composition.

The invention relates to a composition containing a catalyst having high catalytic stability for conducting oxidative coupling of methane (OCM) at high carbon efficiency, while improving both methane and oxygen conversion. Particularly, the inventive catalyst is a metal oxide supported catalyst, which contains an alkali metal promoter and a mixed metal oxide component having at least one alkali earth metal and at least one rare earth metal. The metal oxide support is selected in a manner, such that at least a portion of the metal oxide support is capable of reacting with at least a part or whole of the alkali metal promoter under conditions of calcination during catalyst preparation. The invention further provides a method for preparing such a metal oxide supported catalyst composition, using a calcination process. Additionally, the invention further describes a process for producing C.sub.2+ hydrocarbons, using such a catalyst composition.

A multilayer supported oxidative coupling of methane (OCM) catalyst composition (support, first single oxide layer, one or more mixed oxide layers, optional second single oxide layer) characterized by formula A.sub.aZ.sub.bE.sub.cD.sub.dO.sub.x/support; A is alkaline earth metal; Z is first rare earth element; E is second rare earth element; D is redox agent/third rare earth element; the first, second, third rare earth element are not the same; a=1.0; b=0.1-10.0; c=0.1-10.0; d=0-10.0; x balances oxidation states; first single oxide layer (Z.sub.b1O.sub.x1, b1=0.1-10.0; x1 balances oxidation states) contacts support and one or more mixed oxide layers; one or more mixed oxide layers (A.sub.a2Z.sub.b2E.sub.c2D.sub.d2O.sub.x2, a2=1.0; b2=0.1-10.0; c2=0.1-10.0; d2=0-10.0; x2 balances oxidation states; A.sub.aZ.sub.bE.sub.cD.sub.dO.sub.x and A.sub.a2Z.sub.b2E.sub.c2D.sub.d2O.sub.x2 are different) contacts first single oxide layer and optionally second single oxide layer, and second single oxide layer (AO), when present, contacts one or more mixed oxide layers and optionally first single oxide layer.

A multilayer supported oxidative coupling of methane (OCM) catalyst composition (support, first single oxide layer, one or more mixed oxide layers, optional second single oxide layer) characterized by formula A.sub.aZ.sub.bE.sub.cD.sub.dO.sub.x/support; A is alkaline earth metal; Z is first rare earth element; E is second rare earth element; D is redox agent/third rare earth element; the first, second, third rare earth element are not the same; a=1.0; b=0.1-10.0; c=0.1-10.0; d=0-10.0; x balances oxidation states; first single oxide layer (Z.sub.b1O.sub.x1, b1=0.1-10.0; x1 balances oxidation states) contacts support and one or more mixed oxide layers; one or more mixed oxide layers (A.sub.a2Z.sub.b2E.sub.c2D.sub.d2O.sub.x2, a2=1.0; b2=0.1-10.0; c2=0.1-10.0; d2=0-10.0; x2 balances oxidation states; A.sub.aZ.sub.bE.sub.cD.sub.dO.sub.x and A.sub.a2Z.sub.b2E.sub.c2D.sub.d2O.sub.x2 are different) contacts first single oxide layer and optionally second single oxide layer, and second single oxide layer (AO), when present, contacts one or more mixed oxide layers and optionally first single oxide layer.

A multilayer supported oxidative coupling of methane (OCM) catalyst composition (support, first single oxide layer, one or more mixed oxide layers, optional second single oxide layer) characterized by formula A.sub.aZ.sub.bE.sub.cD.sub.dO.sub.x/support; A is alkaline earth metal; Z is first rare earth element; E is second rare earth element; D is redox agent/third rare earth element; the first, second, third rare earth element are not the same; a=1.0; b=0.1-10.0; c=0.1-10.0; d=0-10.0; x balances oxidation states; first single oxide layer (Z.sub.b1O.sub.x1, b1=0.1-10.0; x1 balances oxidation states) contacts support and one or more mixed oxide layers; one or more mixed oxide layers (A.sub.a2Z.sub.b2E.sub.c2D.sub.d2O.sub.x2, a2=1.0; b2=0.1-10.0; c2=0.1-10.0; d2=0-10.0; x2 balances oxidation states; A.sub.aZ.sub.bE.sub.cD.sub.dO.sub.x and A.sub.a2Z.sub.b2E.sub.c2D.sub.d2O.sub.x2 are different) contacts first single oxide layer and optionally second single oxide layer, and second single oxide layer (AO), when present, contacts one or more mixed oxide layers and optionally first single oxide layer.

A method of performing an oxidative coupling of methane (OCM) reaction to produce C.sub.2+ compounds using a low temperature gas mixture feed is provided. The method includes introducing a gas mixture feed containing methane, oxygen, hydrogen, and carbon monoxide at a temperature of less than or equal to 300° C. to an inlet of an OCM reactor, which contains a combustion catalyst and an OCM catalyst. At least a portion of the gas mixture feed is combusted using the combustion catalyst to generate a heated gas mixture having a temperature of at least 450° C. The heated gas mixture contacts the OCM catalyst to initiate an OCM reaction and produce an OCM effluent that includes C.sub.2+ compounds. A system for performing an OCM reaction using a low temperature feedstock gas mixture is also provided.

A method of performing an oxidative coupling of methane (OCM) reaction to produce C.sub.2+ compounds using a low temperature gas mixture feed is provided. The method includes introducing a gas mixture feed containing methane, oxygen, hydrogen, and carbon monoxide at a temperature of less than or equal to 300° C. to an inlet of an OCM reactor, which contains a combustion catalyst and an OCM catalyst. At least a portion of the gas mixture feed is combusted using the combustion catalyst to generate a heated gas mixture having a temperature of at least 450° C. The heated gas mixture contacts the OCM catalyst to initiate an OCM reaction and produce an OCM effluent that includes C.sub.2+ compounds. A system for performing an OCM reaction using a low temperature feedstock gas mixture is also provided.