Development Of A Novel Catalyst Carrier For CO Sulfur-tolerant Catalysts

This paper described the hydrothermal synthesis of a carrier for sulfur-tolerant CO shift catalyst for application at high pressure and higher steam/gas ratio. Nanotechnology was adopted in preparation of the carrier to overcome the problem with existing catalysts (i. e., poor anti-rehydration properties and liability to deactivation). Pseudo-bohemite, gibbsite and magnesium hydroxide were used to synthesize magnesia-alumina spinel precursor at 180℃; urea was used as the structural modifier to adjust structure of the precursor powder, so as to enhance the content of composite hydroxide hydrates, which are more liable to be converted to magnesia-alumina spinel; Mineralization agent NH4F was used to regulate shape of the powder so as to lower the amount of bohemite needle crystals and form flake-shape powder; surfactant was introduced before drying to form superfine magnesia-alumina spinel powder with much smaller particle size than the raw material. Carrier with spinel structure was prepared after forming, drying and calcinations at 550℃, with crush strength higher than 150 N/cm. With framework of spinel, free γ-Al2O3 and water-absorbing MgO were greatly eliminated, and thus improve the anti-rehydration properties. Long-term hydrothermal test and tests in raw coal gas showed that anti-rehydration and catalytic properties of the catalyst based upon this carrier were superior to that of reference K8-11 and QCS-01, and can meet the requirement of pressurized gasification processes.