Process for production of elemental iron

Abstract

The invention is directed to a process to prepare elemental iron by contacting an iron ore feed with a reducing gas to obtain iron and an off-gas. The reducing gas is prepared by performing the following steps (a) partially oxidizing a mixture comprising a sulphur containing solid carbonaceous fuel and gaseous CO 2 as carrier medium with oxygen, by supplying an oxygen containing gas and the solid carbonaceous fuel to a burner, thereby obtaining a gas comprising H 2 , CO, CO 2 and H 2 S; (b) removing CO 2 and H 2 S from the gas obtained in step (a) to obtain the reducing gas comprising H 2 and CO and a first stream comprising CO 2 and H 2 S; (c) reducing the content of H 2 S in the first stream comprising CO 2 and H 2 S obtained in step (b) in a liquid redox type process and (d) recycling at least part of the CO 2 obtained in step (c) to step (a).

1 . A process to prepare elemental iron by contacting an iron ore feed with a reducing gas to obtain iron and an off-gas, wherein the reducing gas is prepared by performing the following steps
 (a) partially oxidizing a mixture comprising a sulphur containing solid carbonaceous fuel and gaseous CO 2  as carrier medium with oxygen, by supplying an oxygen containing gas and the solid carbonaceous fuel to a burner, thereby obtaining a gas comprising H 2 , CO, CO 2  and H 2 S;   (b) removing CO 2  and H 2 S from the gas obtained in step (a) to obtain the reducing gas comprising H 2  and CO and a first stream comprising CO 2  and H 2 S;   (c) reducing the content of H 2 S in the first stream comprising CO 2  and H 2 S obtained in step (b) in a liquid redox type process and (d) recycling at least part of the CO 2  obtained in step (c) to step (a).   
     
     
         2 . The process according to  claim 1 , wherein
 the off-gas comprises CO 2  and H 2 S, and wherein CO 2  and H 2 S are removed from the off-gas to obtain a recycle reducing gas comprising CO and H 2  and a second stream comprising CO 2  and H 2 S, and wherein   the recycle reducing gas is used as reducing gas, and wherein the first and second stream comprising CO 2  and H 2 S are mixed and a mixture of the first and second stream comprising CO 2  and H 2 S is subjected to step (c).   
     
     
         3 . The process according to  claim 1 , wherein the weight ratio of CO 2  to the carbonaceous fuel in step (a) is less than 0.5 on a dry basis. 
     
     
         4 . The process according to  claim 1 , wherein the sulfur containing solid carbonaceous fuel is chosen from the group consisting of coal, petroleum coke, peat and solid biomass. 
     
     
         5 . The process according to  claim 1 , wherein the gas obtained in step (a) also comprises HCN and COS and wherein step (b) is performed by
 (i) contacting the gas as obtained in step (a) with a HCN/COS hydrolysis catalyst to convert HCN to NH 3  and COS to H 2 S, followed by removal of water and ammonia from the gas by cooling and/or scrubbing;   (ii) contacting the gas obtained in step (i) with a solvent, which is selective for absorbing CO 2  and H 2 S.   
     
     
         6 . The process according to  claim 5 , wherein the solvent comprises one or more compounds selected from the group consisting of N-methylpyrrolidone (NMP), dimethyl ether of polyethylene glycol (DMPEG), methanol, an amine and mixtures of amines with sulfolane. 
     
     
         7 . The process according to  claim 6 , wherein the solvent comprises di-isopropanol amine (DIPA) 
     
     
         8 . The process according to  claim 6  wherein the solvent comprises an amine and sulfolane. 
     
     
         9 . The process according to  claim 1 , wherein step (c) is performed by liquid redox type process by contacting the stream of CO 2  and H 2 S obtained in step (b) with an aqueous reactant solution comprising an iron (III) chelate of an organic acid or complex reactant system to produce elemental sulphur which is recovered as a by-product of the process either prior to or subsequent to regeneration of the reactant. 
     
     
         10 . The process according to  claim 1 , wherein a part of the CO 2  as obtained in step (c) is used for enhanced oil recovery, CO 2  sequestration or coal bed methane extraction. 
     
     
         11 . The process according to  claim 1 , wherein a part of the CO 2  as obtained in step (c) is injected into a subterranean zone to obtain a desired pressure in the subterranean zone to enhance the recovery of a hydrocarbon containing stream as produced from the subterranean zone. 
     
     
         12 . The process according to  claim 1 , wherein part of the reducing gas obtained in step (b) is used as a fuel in a gas turbine to generate power.