Influence of Sulfur Activity on the Reforming Reaction during Production of Iron Carbide with CO-CH4-H2-H2S Mixtures in Fluidized Bed

Abstract

Iron carbide was produced in a laboratory scale fluidized bed by carburizing reduced iron with CO-CH 4 -H 2 -H 2 S mixtures at 873K. The rates of carbide formation and steam reforming of methane have been measured by means of X-ray diffraction for the sampled particles and the outlet gas analysis. On the influence of sulfur activity and pressurization in the carburizing atmosphere, special attention was paid. With an increase in the total pressure, the carburization rate increases. The carburization with CH 4 proceeds to some extent, but that with CO-H 2 -H 2 O-H 2 S mixtures is the predominant reaction. At as low temperature as 873K, the rate of the reforming reaction is very slow and almost independent of the total pressure. Sulfur adsorbed on the surface of pores of reduced iron can suppress the decomposition of the iron carbides and the precipitation of free carbon, but it also retards the reforming reaction by poisoning the catalytic effect of reduced iron. Addition of some water vapor to the reaction gas also prevents the decomposition and the precipitation.