Hydrogen Production from the Steam−Iron Process with Direct Reduction of Iron Oxide by Chemical Looping Combustion of Coal Char

Abstract

Experimental results performed with a fluidized-bed reactor supported the feasibility of the three processes including direct reduction of iron oxide by char, H 2 production by the steam−iron process, and the oxidation of Fe 3O 4 resulting from the steam−iron process to the original Fe 2O 3 by air. Chars resulting from a Chinese lignite loaded with K 2CO 3 were used successfully as a reducing material, leading to the reduction of Fe 2O 3 to FeO and Fe for the steam−iron process, which was confirmed by both the off-gases concentrations and X-ray diffractometer analysis. The reduction of Fe 2O 3 by K-10-char at 1073 K is desirable from the perspective of the carbon conversion rate and high concentration of CO 2. The carbon in char was completely converted to CO 2 when the mass ratio of Fe 2O 3/K-10-char was increased to 10/0.3. The oxidation rate of K-10-char by Fe 2O 3 without a gasifying agent was comparable to the K-10-char steam gasification rate. The fractions of FeO and Fe in the reduced residue were ...