The present disclosure relates to a power production system that is adapted to achieve high efficiency power production using partial oxidation of a solid or liquid fuel to form a partially oxidized stream that comprises a fuel gas. This fuel gas stream can be one or more of quenched, filtered, and cooled before being directed to a combustor of a power production system as the combustion fuel. The partially oxidized stream is combined with a compressed recycle CO.sub.2 stream and oxygen. The combustion stream is expanded across a turbine to produce power and passed through a recuperator heat exchanger. The expanded and cooled exhaust stream can be further processed to provide the recycle CO.sub.2 stream, which is compressed and passed through one or more recuperator heat exchangers in a manner useful to provide increased efficiency to the combined systems.

The present application relates to a production plant comprisinga synthesis gas generation step (1) arranged to receive a hydrocarbon or carboneous feedstock (2) and in a synthesis gas generation process provide a syngas, a production step (4) arranged to receive the syngas and produce a product stream (5), a reverse water gas shift step (4) arranged to receive a H2 rich gas stream (7) and a C02 feed (8) and in a RWGS step obtain a reverse shifted gas stream (9), andmeans (10) for adding said reverse shifted gas stream (9) to the synthesis gas stream (3).

A method of converting carbon containing compounds such as coal, methane or other hydrocarbons into a liquid hydrocarbon fuel utilizes a high pressure, high temperature reactor which operates upon a blend of a carbon compound including CO.sub.2 and a carbon source, a catalyst, and steam. Microwave power is directed into the reactor. The catalyst, preferably magnetite, will act as a heating media for the microwave power and the temperature of the reactor will rise to a level to efficiently convert the carbon and steam into hydrogen and carbon monoxide.

A plant, such as a hydrocarbon plant, is provided, which has a syngas stage for syngas generation and a synthesis stage where the syngas is synthesized to produce syngas derived product, such as hydrocarbon product. The plant makes effective use of various streams; in particular, CO.sub.2 and H.sub.2. The plant does not comprise an external feed of hydrocarbons. A method for producing a product stream, such as a hydrocarbon product stream is also provided.

The present invention relates to a novel heterogeneous catalyst for selective carbon dioxide methanation reaction having high activity and long-term stability, wherein the catalyst comprising of at least one alkali promoter metal, active metals selected from Nickel and Iron and a stable support for active metals having combination of CeO.sub.2-Al.sub.2O.sub.3. Further, the present invention provides a process for synthesis of said catalyst. Secondly, the present invention also provides a sustainable process for synthesis of methane using said novel heterogenous catalyst. The benefits of present invention are that it provides a sustainable CO.sub.2 methanation process as the novel outstanding catalyst having high performance and long-term stability and totally eliminates catalyst regeneration or reloading step due to its very long-term stability for >1000 h.