A methane (CH.sub.4) gas is synthesized from carbon dioxide (CO.sub.2) and hydrogen (H.sub.2) using catalyst-dielectric barrier discharge (DBD) plasma at room temperature and atmospheric pressure. In the method and apparatus for synthesizing methane gas of the invention, methane (CH.sub.4) gas, which is synthetic natural gas, can be effectively synthesized only from carbon dioxide (CO.sub.2) and hydrogen (H.sub.2) using DBD plasma at room temperature and atmospheric pressure, and also, additional heating and pressurization devices are not used during the methane gas synthesis process, thus reducing production costs and realizing high-value-added processing due to the absence of risks during the processing.

Aspects of the present disclosure involve a power supply circuit for powering a plasma reactor and more specifically initiating and maintain a plasma therein, and that can operate with power from an intermittent power source. The power supply may include an auxiliary-power supply or trigger circuit, in addition to a primary-power supply circuit, which can reduce the need for high-voltage equipment in the high-power section of the power supply. In one particular use, the power supply includes a high-voltage power output that may be used for generating a plasma between electrodes, for example, in a nitrogen-fixation plasma system. The power supply circuit may provide the flexibility to power a plasma reactor using an intermittent power source, such as solar, wind, and/or a periodic low-cost power grid, while reducing wasteful power conditioning, lowering the cost of operation, and increasing the efficiency of chemical production from the renewable energy.

A process comprises feeding a stream of reactant compounds to a reactor and discharging a liquid plasma into the reactant stream in the reactor, wherein the plasma initiates or accelerates a reaction of the reactant compounds to form a product composition. The reactor can comprise one or more chambers, a high-voltage electrode positioned at a first portion of the one or more chambers, a ground electrode positioned at a second portion of the one or more chambers, and a dielectric plate between the ground electrode and the high-voltage electrode that comprises openings through which the reactant stream can pass from the first portion to the second portion or from the second portion to the first portion. Discharging the plasma can include supplying electrical power to the high-voltage electrode such that plasma is discharged where the reactant stream flows through the openings.

A system and method for producing graphene includes a discharge assembly and a substrate assembly. The discharge assembly includes a cathode and an anode, which in one embodiment are offset from each other. The anode produces a flux stream that is deposited onto a substrate. A collection device removes the deposited material from the rotating substrate. The flux stream can be a carbon vapor, with the deposited flux being graphene.

A method for preparing high-temperature, active particle-containing steam. The method includes: 1) preparing steam; selecting one or several non-oxidizing gases as a working gas; ionizing the working gas into a plasma working medium by using a plasma generator; and 2) injecting the plasma working medium into a high-temperature steam generator to form high-temperature ionized environment while introducing the steam into the high-temperature steam generator for allowing the steam to contact with the plasma working medium so that the steam is heated and activated to form active particle-containing steam. A device for preparing the high-temperature, active particle-containing steam is also provided.

A reactor for reforming a liquid hydrocarbon fuel, and associated processes and systems, are described herein. In one example, a two stage process is disclosed in which a first reactor is coupled to a second stage reactor having a reaction volume greater than the first reactor. In the first reactor, the liquid hydrocarbon fuel is partially reformed and thereafter is inputted into the second stage reactor for complete partial oxidation. The reaction product is at last partially synthesis gas, a mixture of carbon monoxide, hydrogen, as well as other low hydrocarbons such as methane, ethylene, ethane, and acetylene. The low hydrocarbons can be reformed further in a solid oxide fuel cell. A portion of the gaseous, rotating contents of the second stage reactor may be input into the first reactor to help generate and sustain rotation within the first reactor.

Systems and methods for plasma based synthesis of graphitic materials. The system includes a plasma forming zone configured to generate a plasma from radio-frequency radiation, an interface element configured to transmit the plasma from the plasma forming zone to a reaction zone, and the reaction zone configured to receive the plasma. The reaction zone is further configured to receive feedstock material comprising a carbon containing species, and convert the feedstock material to a product comprising the graphitic materials in presence of the plasma.

A system and method for treating natural gas, including producing natural gas from a subterranean formation via a wellhead system to a nonthermal plasma (NTP) catalytic unit, converting by the NTP unit carbon dioxide (CO.sub.2) and hydrogen sulfide (H.sub.2S) in the natural gas into carbon monoxide (CO), elemental sulfur (S), and hydrogen (H.sub.2), and removing the elemental sulfur as liquid elemental sulfur to give treated natural gas. The NTP unit may convert methane (CH.sub.4) in the natural gas to heavier hydrocarbons.

The invention includes a system for producing a carbon dioxide conversion product, where the system includes a carbon dioxide gas source providing carbon dioxide; a delivery system for the carbon dioxide in fluid communication with the carbon dioxide gas source, wherein the delivery system delivers the carbon dioxide gas into a plasma reactor, and wherein the plasma reactor energizes the carbon dioxide gas as a plasma to produce activated carbon dioxide species; a secondary reactant source providing a secondary reactant in a secondary reactant stream that is separated from the carbon dioxide gas, wherein the secondary reactant stream is directed to contact the activated carbon dioxide species in a reaction zone, and wherein the contact between the activated carbon dioxide species and the secondary reactant in the reaction zone produces a reaction that yields the carbon dioxide conversion product. The invention also includes methods of the use of such a system for producing a carbon dioxide conversion product.

The invention includes a system for producing a nitrogen fixation product, where the system includes a nitrogen gas source providing nitrogen gas; a delivery system for the nitrogen gas in fluid communication with the nitrogen gas source, wherein the delivery system delivers the nitrogen gas into a plasma reactor, and wherein the plasma reactor energizes the nitrogen gas as a plasma to produce activated nitrogen species; a secondary reactant source providing a secondary reactant in a secondary reactant stream that is separated from the nitrogen gas, wherein the secondary reactant stream is directed to contact the activated nitrogen species in a reaction zone, and wherein contact between the activated nitrogen species and the secondary reactant produces a reaction that yields the nitrogen fixation product. The invention also includes methods of the use of such a system for producing a nitrogen fixation product.