Many separation and reaction processes in industrial applications require the use of the granules-composite. However, the granules prepared by the conventional methods, i.e. tumble growth, tabletting and extrusion, suffer from some drawbaks such as poor mechanical strength and low attrition resistance.

The iodine-sulfur (IS) cycle consist of the following reactions: (1) decomposition of H2SO4 to SO2 and H2O, (2) decomposition of HI to H2 and I2, (3) production of HI and H2SO4 through reaction of I2 with SO2 and H2O. Metal oxides are considered as active catalysts for the sulfuric acid decomposition in temperature range of 600-950 ºC. Noble metals are reliably as highly active catalysts for decomposition reaction, but non-noble catalysts should be developed from the economic point of view.

The catalysts should be insulated in Al2O3 matrix to disperse and stabilize the active component. To overcome the problem of poor mechanical strength and attrition resistance, catalysts granules have be prepared by combination of the Yoldas sol-gel process and the oil-drop method. Furthermore, a coating of the granules with meso-structured barium sulfate could prevent the active component of the catalyst from the corrosive environment of the sulfuric acid.

In our work, the optimum composition of granules based on Cu/Fe alumina has been identified in the SO3 reaction. In this presentation, we will prepare the granule type of catalyst coated by BaSO4 for the direct decomposition of H2SO4 to produce hydrogen in IS cycle. The granule will be coated carefully by spray pyrolysis combined with fluidized system. The catalytic performance of the catalyst will be investigated by both SO3 and H2SO4 decomposition.

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