A method for using a downdraft gasifier comprising a housing and a refractory stack contained within the housing. The refractory stack may comprise various sections. Apertures in the sections may be aligned to form multiple columnar cavities. Each columnar cavity may comprise an individual oxidation zone. The method of use may include the steps of placing a feedstock into an upper portion of the refractory stack, measuring the temperature of each columnar cavity, and adjusting the flow of oxygen to a particular columnar cavity to maintain the temperature of the particular columnar cavity within a particular range.

This invention is directed to novel mixed transition metal iron (II/III) catalysts for the extraction of oxygen from CO.sub.2 and the selective reaction with organic compounds.

Provided herein are systems, methods and equipment that include Integrated Gasification Combined-Cycle technology to retrofit existing plants, that include, e.g., subsystems for separating char fines from syngas after it emerges from an internally-circulating fluidized bed carbonizer and injecting the char into the carbonizer draft tube as a fuel source. Efficiency and power generation are thus increased to the extent that inclusion of carbon capture systems are now possible for existing coal plants in order to significantly reduce carbon dioxide emissions.

The torrefaction unit 1 comprises at least one multiple hearth furnace 2 which is heated by a heat transfer fluid 16 comprising hot water taken form a water space 21 of a steam drum 11. The heat transfer fluid 16 is guided through a water circuit 20 to a heating system 19 of the at least one multiple hearth furnace 2. This means the multiple hearth furnace 2 is heated to a torrefaction temperature indirectly by the use of hot water as heat transfer fluid 16. This is environmentally advantageous. The torrefaction gas 3 created by the torrefaction of material comprising biomass such as municipal solid waste is preferably partially oxidized in a partial oxidation reactor 23 for creating syngas. Preferably, a part of the thermal energy of the syngas is used in an evaporator 9 and/or a superheater 13 to heat water and/or steam and/or to evaporate water. The evaporated water is preferably guided to a steam space 22 of the steam drum 11 and can, thus, be used to heat the heat transfer fluid 16. The partial oxidation reactor 23 and the temperature of the heat transfer fluid 16 can be controlled independently allowing to one single partial oxidation reactor 23 for at least two multiple hearth furnaces 2.

Exemplary reactor systems may include multiple reactors in fluid communication. Oxygen carrier particles comprising a support material and metal oxide can be provided to a first reactor along with flue gas comprising carbon dioxide (CO2). An output of the first reactor is free or substantially free of carbon dioxide (CO2). The oxygen carrier particles can then be provided to one or more reactors in the system along with a hydrocarbon stream and, in some instances, an oxidizing stream. Outlets from these one or more reactors may include hydrogen gas (H2), carbon monoxide (CO), and/or other species, depending upon the content of the hydrocarbon streams and the oxidizing streams.

Novel redox based systems for fuel and chemical production with in- situ CO.sub.2 capture are provided. A redox system using one or more chemical intermediates is utilized in conjunction with liquid fuel generation via indirect Fischer-Tropsch synthesis, direct hydro genation, or pyrolysis. The redox system is used to generate a hydrogen rich stream and/or CO.sub.2 and/or heat for liquid fuel and chemical production. A portion of the byproduct fuels and/or steam from liquid fuel and chemical synthesis is used as part of the feedstock for the redox system.

The present invention relates to a cyclone for gas/solid separation in a plant for chemical looping combustion of a hydrocarbon feedstock using reactors operating as circulating fluidized beds. The novel cyclone has a specific inlet pipe of which a lower wall and one of the lateral walls are inclined and which has at least one auxiliary-gas injection means at the lower wall, making it possible to reduce the deposition of solid matter at the inlet of the cyclone, to optionally carry out chemical reactions inside the cyclone, and to improve the efficiency of the cyclone.

A system for converting carbonaceous fuels is provided. The system includes a gaseous fuel conversion reactor, a solid fuel conversion reactor, and a fuel pretreatment fluidized bed reactor disposed between the gaseous fuel conversion reactor and the solid fuel conversion reactor. The fuel pretreatment fluidized bed reactor devolatilizes a solid fuel using heat to produce an off-gas and a devolatilized solid fuel. The gaseous fuel conversion reactor converts the off-gas from the fuel pretreatment fluidized bed reactor to a product gas stream comprising carbon dioxide and water. The solid fuel conversion reactor receives a mixture of oxygen carrier solids and devolatilized solid fuel from the pretreatment reactor discharge and reduces the devolatilized solid fuel with the oxygen carrier solids to convert the devolatilized solid fuel to an intermediate gas.

The invention relates to an integrated method for gasification and indirect combustion of a solid hydrocarbon feedstock in a chemical loop, comprising: contacting solid hydrocarbon feedstock (1) with water (2) in a gasification reaction zone RG in order to discharge ashes (9) and to produce a gaseous effluent (3) comprising syngas and water, supplying reduction reaction zone RR of a redox chemical loop with at least part of gaseous effluent (3) produced in the gasification reaction zone in order to produce a CO.sub.2 and H.sub.2O-concentrated gaseous effluent (4), reoxidizing the oxygen-carrying solid particles from reduction reaction zone RR of the chemical loop in oxidation reaction zone RO by means of an oxidizing gas (6) and discharging fumes (7). The invention also relates to a plant allowing said integrated method to be implemented.

The disclosure provides a metal ferrite oxygen carrier for the chemical looping combustion of solid carbonaceous fuels, such as coal, coke, coal and biomass char, and the like. The metal ferrite oxygen carrier comprises MFe.sub.xO.sub.y on an inert support, where MFe.sub.xO.sub.y is a chemical composition and M is one of Mg, Ca, Sr, Ba, Co, Mn, and combinations thereof. For example, MFe.sub.xO.sub.y may be one of MgFe.sub.2O.sub.4, CaFe.sub.2O.sub.4, SrFe.sub.2O.sub.4, BaFe.sub.2O.sub.4, CoFe.sub.2O.sub.4, MnFeO.sub.3, and combinations thereof. The MFe.sub.xO.sub.y is supported on an inert support. The inert support disperses the MFe.sub.xO.sub.y oxides to avoid agglomeration and improve performance stability. In an embodiment, the inert support comprises from about 5 wt. % to about 60 wt. % of the metal ferrite oxygen carrier and the MFe.sub.xO.sub.y comprises at least 30 wt. % of the metal ferrite oxygen carrier. The metal ferrite oxygen carriers disclosed display improved reduction rates over Fe.sub.2O.sub.3, and improved oxidation rates over CuO.