Catalyst preparation spray drying

In Du Pont patents (116) the catalyst is prepared by spray-drying a mixture of colloidal siUca or other carriers and Pt/Pd salts. Aqueous hydrogen peroxide solutions up to 20 wt % ate reported for reaction conditions of 10—17°C and 13.7 MPa (140 kg/cm ) with 60—70% of the hydrogen feed selectively forming hydrogen peroxide. 

The solid base catalysts were prepared by dissolving Cs(N03)2 (Aldrich, 99%) in the minimum amount of distilled water before addition to the silica support by spray impregnation a method used to give a high dispersion of the metal salt on the support. The amount of each precursor added was calculated in order to give a 10% loading of metal on each catalyst. The catalyst was then dried in an oven overnight at 373 K. Prior to the reaction the catalyst was calcined in situ in a flow of N2 (BOC, 02 free N2) at 10 cm3 min"1 for 2 hours at 723 K. 

Catalyst Y-G was prepared in conformity with the spray-drying method of Yates and Garland 27). Ni(N03)2 was dissolved in a small amount of distilled water, whereupon acetone and the requisite amount of aerosil were successively added to it. The slurry was transferred to an atomizer and sprayed with continuous agitation. The spray was directed to a glass surface and the particles adhering to this surface were dried by leading a stream of air over them. 

Catalysts were prepared using a spray dried slurry of the appropriate zeolite, clay and a proprietary inert binder. 

The crucial step in FCC catalyst production is the so called spray drying, where both the shaping and the drying of the composite catalyst are effected. This step is often overlooked in the open literature on zeolite preparation and few authors describe details on this operation. 

The chapters in Characterization and Catalyst Development An Interactive Approach, assembled from both academic and industrial contributors, give a unique perspective on catalyst development Some chapters thoroughly characterize the catalyst prior to plant evaluation, whereas others utilize characterization to explain performance variances. Some new types of catalysts incorporated into this volume include the preparation of novel catalyst supports based on alumina and hydrous titanates. Attrition-resistant catalysts and ultrafine ceramics were prepared by modified spray-drying methods. New catalyst compositions based on vanadium-containing anionic clays were proposed for oxidation. A recently commercialized catalyst based on magnesium spinel was proposed for use in the abatement of sulfur oxide pollutants in fluid... 

Micrographs obtained by EPMA are shown in Figure 4. The sample in this case was VPO with 10% amorphous silica as the hard phase. This composition was prepared by spray drying an aqueous slurry with about 40% solids made of l-2 im particles of the VPO catalyst precursor and polysilicic acid. The back-scattered image shows all elements present in the porous microsphere. The X-ray image of silicon clearly shows this element concentrated exclusively on the periphery of the microsphere. Independent X-ray diffraction and electron diffraction analysis of the peripheral layer of the microspheres showed that the silicon is present as amorphous silica. 

A recent patent by DSM [121] claims catalysts very similar to those reported by Furuoya [120]. Indeed, the catalyst preparation is the same as the one described by Furuoya [120bj. The only difference concerns the addition of siUca in relevant amounts, in the form of silica sol. This is claimed to give better reproducibiUty in performance for catalysts prepared in the powder form (by spray-drying). The best performance reported is 95% conversion and 58% yield to nitriles (fumaronitrile -1-maleonitrile -1- succinonitrile, the saturated dinitrile). The authors report the use of a low O2 concentration, with a feed composition of 0.50% butadiene, 2.50% ammonia and 4.4% oxygen (the balance being nitrogen). 

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