One variation of a method includes: ingesting an air sample captured during an air capture period at a target location for collection of a first mixture including carbon dioxide and a first concentration of impurities; conveying the first mixture through a liquefaction unit to generate a second mixture including carbon dioxide and a second concentration of impurities less than the first concentration of impurities; in a methanation reactor, mixing the second mixture with hydrogen to generate a first hydrocarbon mixture comprising a third concentration of impurities comprising nitrogen, carbon dioxide, and hydrogen; conveying the first hydrocarbon mixture through a separation unit configured to remove impurities from the first hydrocarbon mixture to generate a second hydrocarbon a fourth concentration of impurities less than the third concentration of impurities; and depositing the second hydrocarbon mixture in a diamond reactor containing a set of diamond seeds to generate a first set of diamonds.

One variation of a method includes: ingesting an air sample captured during an air capture period at a target location for collection of a first mixture including carbon dioxide and a first concentration of impurities; conveying the first mixture through a liquefaction unit to generate a second mixture including carbon dioxide and a second concentration of impurities less than the first concentration of impurities; in a methanation reactor, mixing the second mixture with hydrogen to generate a first hydrocarbon mixture comprising a third concentration of impurities comprising nitrogen, carbon dioxide, and hydrogen; conveying the first hydrocarbon mixture through a separation unit configured to remove impurities from the first hydrocarbon mixture to generate a second hydrocarbon a fourth concentration of impurities less than the third concentration of impurities; and depositing the second hydrocarbon mixture in a diamond reactor containing a set of diamond seeds to generate a first set of diamonds.

One variation of a method includes: ingesting an air sample captured during an air capture period at a target location for collection of a first mixture including carbon dioxide and a first concentration of impurities; conveying the first mixture through a liquefaction unit to generate a second mixture including carbon dioxide and a second concentration of impurities less than the first concentration of impurities; in a methanation reactor, mixing the second mixture with hydrogen to generate a first hydrocarbon mixture comprising a third concentration of impurities comprising nitrogen, carbon dioxide, and hydrogen; conveying the first hydrocarbon mixture through a separation unit configured to remove impurities from the first hydrocarbon mixture to generate a second hydrocarbon a fourth concentration of impurities less than the third concentration of impurities; and depositing the second hydrocarbon mixture in a diamond reactor containing a set of diamond seeds to generate a first set of diamonds.

A method for operation of an industrial plant having an energy accumulator unit for production of synthetic natural gas, a power plant unit for production of electricity, an oxygen tank, a carbon dioxide tank and a water tank. In a first operation mode the energy accumulator unit is supplied with excessed electricity from the public grid to produce synthetic natural gas, wherein the produced synthetic natural gas is discharged in a gas network, while oxygen and water which are produced together with the synthetic natural gas are stored in the oxygen tank and the water tank correspondingly. In a second operation mode gas from the gas network together with oxygen from the oxygen tank and water from the water tank are used in the power plant unit to produce electricity, which is supplied to the public grid. This way electricity production excess is efficiently accumulated for industrial or municipal use.

A method for operation of an industrial plant having an energy accumulator unit for production of synthetic natural gas, a power plant unit for production of electricity, an oxygen tank, a carbon dioxide tank and a water tank. In a first operation mode the energy accumulator unit is supplied with excessed electricity from the public grid to produce synthetic natural gas, wherein the produced synthetic natural gas is discharged in a gas network, while oxygen and water which are produced together with the synthetic natural gas are stored in the oxygen tank and the water tank correspondingly. In a second operation mode gas from the gas network together with oxygen from the oxygen tank and water from the water tank are used in the power plant unit to produce electricity, which is supplied to the public grid. This way electricity production excess is efficiently accumulated for industrial or municipal use.

A process for preparing C.sub.2 to C.sub.5 paraffins includes introducing a feed stream comprising hydrogen gas and a carbon-containing gas into a reaction zone of a reactor, and converting the feed stream into a product stream comprising C.sub.2 to C.sub.5 paraffins in the reaction zone in the presence of a hybrid catalyst. The hybrid catalyst includes a metal oxide catalyst component and a microporous catalyst component. The metal oxide catalyst component satisfies: an atomic ratio of Cu/Zn from 0.01 to 3.00; an atomic ratio of Cr/Zn from 0.01 to 1.50; and percentage of (Al+Cr) from greater than 0.0 at % to 50.0 at % based on a total amount of metal in the metal oxide catalyst component.

A process for preparing C.sub.2 to C.sub.5 paraffins includes introducing a feed stream comprising hydrogen gas and a carbon-containing gas into a reaction zone of a reactor, and converting the feed stream into a product stream comprising C.sub.2 to C.sub.5 paraffins in the reaction zone in the presence of a hybrid catalyst. The hybrid catalyst includes a metal oxide catalyst component and a microporous catalyst component. The metal oxide catalyst component satisfies: an atomic ratio of Cu/Zn from 0.01 to 3.00; an atomic ratio of Cr/Zn from 0.01 to 1.50; and percentage of (Al+Cr) from greater than 0.0 at % to 50.0 at % based on a total amount of metal in the metal oxide catalyst component.

A process for preparing C.sub.2 to C.sub.5 paraffins includes introducing a feed stream comprising hydrogen gas and a carbon-containing gas into a reaction zone of a reactor, and converting the feed stream into a product stream comprising C.sub.2 to C.sub.5 paraffins in the reaction zone in the presence of a hybrid catalyst. The hybrid catalyst includes a metal oxide catalyst component and a microporous catalyst component. The metal oxide catalyst component satisfies: an atomic ratio of Cu/Zn from 0.01 to 3.00; an atomic ratio of Cr/Zn from 0.01 to 1.50; and percentage of (Al+Cr) from greater than 0.0 at % to 50.0 at % based on a total amount of metal in the metal oxide catalyst component.

A biogas-utilizing methanation system includes: a solid oxide fuel cell using a to-be-treated gas as a fuel gas; a hydrogen production device capable of producing hydrogen by using power of a renewable energy power generation device; and a methanation device capable of methanating carbon dioxide in the system with the hydrogen produced by the hydrogen production device. The carbon dioxide in the system can be stored in a storage device on the basis of the supply amount of the to-be-treated gas or the power of the renewable energy power generation device.

A biogas-utilizing methanation system includes: a solid oxide fuel cell using a to-be-treated gas as a fuel gas; a hydrogen production device capable of producing hydrogen by using power of a renewable energy power generation device; and a methanation device capable of methanating carbon dioxide in the system with the hydrogen produced by the hydrogen production device. The carbon dioxide in the system can be stored in a storage device on the basis of the supply amount of the to-be-treated gas or the power of the renewable energy power generation device.