Spray-dried catalysts

Particle Structure. First of all, the particle structure has a fundamental influence on the degradation propensity. The extent of degradation as well as its mode will strongly depend on whether the particle is a single crystal, has an amorphous structure or is an agglomerate. For example, spray-dried catalysts, which are often used in fluidized bed reactors, are... 

Calcination of the spray dried catalyst in the regenerator zone at 390 C, then the active catalyst is produced by running the n-butane oxidation in air for several hours in the ... 

Alternate Modes of Catalyst Physisorption. Other forms of catalyst delivery to the reactor have been implemented. Catalyst solution has been injected directly into fluidized-bed gas-phase reactors (39), evidently creating a mist of in situ spray-dried catalyst. Spray-dried catalyst has been prepared ex situ as well, in an attempt to better control the morphology of the particles (40). Solid catal54ically active materials have also resulted from precipitation of MAO by aliphatic solvent (41) and through a low conversion polymerization (prepolymerization) prior to introduction to the large-scale polymerization medium (42). 

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. 

Fluidized-bed reactor systems put other unique stresses on the VPO catalyst system. The mixing action inside the reactor creates an environment that is too harsh for the mechanical strength of a vanadium phosphoms oxide catalyst, and thus requires that the catalyst be attrition resistant (121,140,141). To achieve this goal, vanadium phosphoms oxide is usually spray dried with coUoidal siUca [7631-86-9] or polysiUcic acid [1343-98-2]. Vanadium phosphoms oxide catalysts made with coUoidal sUica are reported to have a loss of selectivity, while no loss in selectivity is reported for catalysts spray dried with polysUicic acid (140). 

Manufacturing Processing and Uses. In commercial production, aqueous urea solution is mixed with acetaldehyde in 1 1 molar ratios. An acid catalyst is introduced into the reaction mixture which is staged at various process temperatures. After neutralization with a base, the CDU is separated from the mother hquor by filtration or spray drying. 

Miscellaneous Refinery catalyst regenerator Municipal incinerators Apartment incinerators Spray drying Precious metal refining... 

Engelhard s in-situ FCC catalyst technology is mainly based on growing zeolite within the kaolin-based particles as shown in Figure 3-9A. The aqueous solution of various kaolins is spray dried to form micR)spheres. The microspheres are hardened in a high-temperature l,3f)(TF/704°C) calcination process. The NaY zeolite is produced by digestion of the microspheres, which contain metakaolin, and mullite with caustic or sodium silicate. Simultaneously, an active matrix is formed with the microspheres. The crystallized microspheres are filtered and washed prior to ion exchange and any final treatment. 

The catalyst manufacturers control PSD of the fresh catalyst, mainly through the spray-drying cycle. In the spray dryer, the catalyst slurry must be effectively atomized to achieve proper distribution. As illustrated in Figure 3-10, the PSD does not have a normal distribution shape. The average particle size (APS) is not actually the average of the catalyst particles, but rather the median value. 

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. 

For the cracking of fraction No.6, a higher c/o-ratio was required for H2 compared with H6 in order to obtain a given conversion level. This reflects the additional activity supplied by the alumina part of the matrix. The contribution of the alumina in the matrix is also seen when fraction No. 6 is cracked over spray dried samples of the matrices only. At a c/o-ratio of 3.0, conversions of 33% and were obtained using the kaolin and the kaolin-alumina matrix, respectively. The tendency for higher coke and gas production at the expense of gasoline over catalyst H6 compared with H2 is also seen for oil No. 6. 

In an exploratory experiment, 13 different powder materials were tested in a FFB ACE unit. Most of the results were unremarkable except for three catalysts a low Z/M commercial maximum distillate catalyst (the same LZM catalyst used in the pilot riser experiment), a spray dried low surface area silica (inert) and the minimum aromatics breakthrough (MAB) catalyst. The inert material was included in the study to represent thermal cracking. The catalysts were steam deactivated in the fixed bed steamer prior to testing. Catalysts and the VGO-B feed properties are displayed in Tables 2.3 and 2.1, respectively. LCO aromatics were measured with 2D GC. Figures 2.7 through 2.9 illustrate the main results. 

Fluid cracking catalysts manufactured prior to 1960 were amorphous mixtures of silica and alumina, combined in such a manner that the mixture could be spray dried into a roughly spherical shape about 70 microns in diameter. Today s cracking catalyst in addition contains an inert filler and zeolite the principle active ingredient 0. today s cracking catalysts. 

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