CALCIUM LOOPING PROCESS FOR HIGH PURITY HYDROGEN PRODUCTION

摘要

A process for producing hydrogen, comprising the steps of: (a) gasifying a fuel into a raw synthesis gas comprising CO, hydrogen, steam and sulfur and halide contaminants in the form of H₂S, COS and HX, where X is a halide; (b) passing the raw synthesis gas through a water gas shift reactor (WGSR) into which CaO and steam are injected, the CaO reacting with the shifted gas to remove CO2, sulfur and halides in a solid-phase calcium-containing product comprising CaCO₃, CaS and CaX₂; (c) separating the solid-phase calcium-containing product from an enriched gaseous hydrogen product; and (d) regenerating the CaO by calcining the solid-phase calcium-containing product at a condition selected from the group consisting of: in the presence of steam, in the presence of CO2, in the presence of synthesis gas, in the presence of H₂ and O₂, under partial vacuum, and combinations thereof. The CaO may have a surface area of at least 12.0 m2/g and a pore volume of at least 0.015 cm3/g, the CaO having a sorption capacity of at least about 70 grams of C02 per kilogram of CaO.