An oxygen carrier (OC) for use in Chemical Looping technology with Oxygen Uncoupling (CLOU) for the combustion of carbonaceous fuels, in which commercial grade metal oxides selected from the group consisting of Cu, Mn, and Co oxides and mixtures thereof constitute a primary oxygen carrier component. The oxygen carrier contains, at least, a secondary oxygen carrier component which is comprised by low-value industrial materials which already contain metal oxides selected from the group consisting of Cu, Mn, Co, Fe, Ni oxides or mixtures thereof. The secondary oxygen carrier component has a minimum oxygen carrying capacity of 1 g of O.sub.2 per 100 g material in chemical looping reactions. Methods for the manufacture of the OC are also disclosed.

The present invention concerns a CLC method and plant for a hydrocarbon feedstock, comprising combustion of said hydrocarbon feedstock (8) on contact with an oxygen carrier in form of particles in a reduction zone (R0), and oxidation of the oxygen carrier from reduction zone (R0) on contact with an oxidizing gas, preferably air, in an oxidation zone. According to the invention, gaseous oxygen is released by the oxygen carrier in a sealing device (S1) operating in a dual fluidized bed and positioned in the path of said carrier from the oxidation zone to the combustion zone, and it is mixed with part of the combustion fumes intended to be recycled to the reduction zone. The gaseous oxygen then enables combustion of the residual unburned species that may be contained in the combustion fumes and/or it participates in the combustion of the hydrocarbon feedstock in the reduction zone.

The present invention relates to a CLC and operation method thereof equipped with a loop seal separator using magnetic oxygen carrier particles and a magnetic separator. And more particularly, the present invention relates to a loop seal separator using magnetic oxygen carrier particles and a magnetic separator, wherein the loop seal separator comprises a duct into which the ash and magnetic oxygen carrier particles, discharged from a reducer, flow; a magnetic separator to separate the ash from the magnetic oxygen carrier particles, flowing into the duct, by magnetic material; an ash discharge pipe to discharge the ash, separated by the magnetic separator; and an oxygen-carrier-particle discharge pipe to encourage the magnetic oxygen carrier particles, separated by the magnetic separator, to flow into an oxidizer.

Oxygen carriers for chemical looping and scalable methods of preparation thereof. Wet impregnation of active metal precursors into porous substrates, together with selective adsorption of the precursors on the pore surfaces, enables transition metal oxides derived from the precursors to disperse throughout the substrate, even at the nanoscale, without increased sintering or agglomeration, thereby forming oxygen carriers suitable for chemical looping. The porous substrate can be an oxide, for example SiO.sub.2. The oxygen carriers can comprise relatively large oxide loadings of over about 20 wt. % and exhibit high reactivity over many regeneration cycles with substantially no loss in oxygen transport capacity or decrease in kinetics. The use of multiple transition metal oxides, for example NiO in addition to CuO, can greatly enhance chemical looping performance.

A system for converting fuel is provided and includes a first reactor comprising a plurality of ceramic composite particles, the ceramic composite particles comprising at least one metal oxide disposed on a support, wherein the first reactor is configured to reduce the at least one metal oxide with a fuel to produce a reduced metal or a reduced metal oxide; a second and reactor configured to oxidize at least a portion of the reduced metal or reduced metal oxide from the said first reactor to produce a metal oxide intermediate; a source of air; and a third reactor communicating with said source of air and configured to regenerate the at least one metal oxide from the remaining portion of the solids discharged from the said first reactor and the solids discharged from the said second reactor for by oxidizing the metal oxide intermediate.

The invention concerns a CLC process, and its installation, producing high purity dinitrogen, comprising:

(a) the combustion of a hydrocarbon feed by reduction of a redox active mass brought into contact with the feed,
(b) a first step for oxidation of the reduced active mass (25) obtained from step (a) in contact with a fraction of a depleted air stream (21b), in order to produce a high purity stream of dinitrogen (28) and a stream of partially re-oxidized active mass (26);
(c) a second step for oxidation of the stream of active mass (26) in contact with air (20) in order to produce a stream of depleted air and a stream of re-oxidized active mass (24) for use in step (a);
(d) dividing the stream of depleted air obtained at the end of step (c) in order to form the fraction of depleted air used in step (b) and a fraction complementary to the depleted air extracted from the CLC.

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, where MFe.sub.xO.sub.y is a chemical composition with 1.5x2.5 and 3.5y4.5 and M is one of Ca, Ba, and combinations thereof. For example, MFe.sub.xO.sub.y may be one of CaFe.sub.2O.sub.4, BaFe.sub.2O.sub.4, MgFe.sub.2O.sub.4. SrFe.sub.2O.sub.4 and combinations thereof. Mixing of the metal ferrite oxygen carrier and the solid carbonaceous fuel generates a product stream comprising at least 50 vol. % CO and H.sub.2. The MFe.sub.xO.sub.y may be supported on an inert support. In an embodiment, the MFe.sub.xO.sub.y comprises at least 30 wt. % of the metal ferrite oxygen carrier the inert support when present comprises from about 5 wt. % to about 60 wt. % of the metal ferrite oxygen carrier.

A system used for converting multiple fuel feedstocks may include three reactors. The reactor system combination can be so chosen that one of the reactors completely or partially converts the fuel while the other generates the gaseous product required by utilizing the gaseous product from the second reactor. The metal-oxide composition and the reactor flow-patterns can be manipulated to provide the desired product. A method for optimizing the system efficiency where a pressurized gaseous fuel or a pressurized utility is used for applications downstream can be used to any system processing fuels and metal-oxide.

An apparatus of hydrocarbon fuel reactors separates and purifies carbon dioxide (CO.sub.2). Interconnected fluidized beds are applied in chemical-looping combustion. A multi-stage reduction reaction is processed with iron-based oxygen carriers. Three reduction stages using the iron-based oxygen carriers are accurately and completely controlled. Each of the three stages is separately processed in an individual space. Oxygen in the iron-based oxygen carriers can be fully released. High-purity CO.sub.2 is obtained. Hydrogen can be produced as an option. Horizontal connection of three reduction reactors is changed into vertical one. An oxidation reactor is further connected. Thus, the whole structure occupies less area and effectively uses vertical space. Not only small space is effectively used; but also high-volume capacity is obtained. Each of the reactors has better geometry flexibility. The tandem reactor in each layer has less geometric influence and limitation. Therefore, each of the reactors can be resized on its own.

The invention relates to a method for operating a fluidized bed boiler, comprising: a) setting the ratio of secondary oxygen containing gas to primary oxygen containing fluidizing gas to a value ranging from 0.0 to 0.8; b) carrying out the combustion of fuel with a fluidized bed comprising ilmenite particle; and to a fluidized bed boiler.