Fluidized catalyst impregnation

Figure 2. Differentiation between liquefaction and gasification by-product waters by pH and redox potential characteristics 1 and 2, waste water PETC coal liquefaction development unit, disposable catalyst, runs DCD 13B and DCD 12 3, waste water, SRC-1 plant 4, scrubber water, light oil, Blacksville No. 2 coal 5, waste water, fixed-bed gasifier, METC 6, waste water, fluidized-bed gasifier, Rosebud coal, PETC 7, gasifier condensate, 40 atm Nt, catalyst-impregnated Illinois 6 coal 8, gasifier condensate, 40 atm He, Montana Rosebud coal.

Several reactors are presently used for studying gas-solid reactions. These reactors should, in principle, be useful for studying gas-liquid-solid catalytic reactions. The reactors are the ball-mill reactor (Fig. 5-10), a fluidized-bed reactor with an agitator (Fig. 5-11), a stirred reactor with catalyst impregnated on the reactor walls or placed in an annular basket (Fig. 5-12), a reactor with catalyst placed in a stationary cylindrical basket (Fig. 5-13), an internal recirculation reactor (Fig. 5-14), microreactors (Fig. 5-16), a single-pellet pulse reactor (Fig. 5-17), and a chromatographic-column pulse reactor (Fig. 5-18). The key features of these reactors are listed in Tables 5-3 through 5-9. The pertinent references for these reactors are listed at the end of the chapter. 

High Si02 zeolites impregnated with 0.8 Fluidized catalyst bed wt% Zn... 

Mungmart M, Kijsirichareonchai U, Tonanon N, Prechanont S. Panpranot J, Yamamoto T, Eiadua A, Sano N, Tanthapanichakoon W, Charinpanitkul T. Metal catalysts impregnated on porous media for aqueous phenol decomposition within three-phase fluidized-bed reactor. J. Hazard. Mater. 2011 185 606-612. 

The catalyst was prepared by impregnating porous alumina particles with a solution of nickel and lanthanum nitrates. The metal loading was 20 w1% for nickel and 10 wt% for lanthanum oxide. The catalyst particles were A group particles [8], whereas they were not classified as the AA oup [9]. The average particle diameter was 120 pm, and the bed density was 1.09 kg m . The minimum fluidization velocity was 9.6 mm s. The settled bed height was around 400 mm. The superficial gas velocity was 40-60 mm s. The reaction rate was controlled by changing the reaction temperature. 

The Econ-Abator system is a fluidized-bed catalytic oxidation system. Catalytic fluidized beds allow for destruction of volatile organic compounds (VOCs) at lower temperatures than conventional oxidation systems (typically 500 to 750°F). The technology uses a proprietary catalyst consisting of an aluminum oxide sphere impregnated with chromium oxide. 

Vanadyl naphthenate (in benzene) was used to metal load aluminas and aluminosilicate gels according to an established procedure (15) the naphthenate was obtained from Pfaltz and Bauer, Inc., and contained 2.9 wt% V. Decomposition of the naphthenate was performed by calcining the impregnated materials for 10 hours at 540 C in air. All catalysts were then steam-aged for five hours with -100% steam at 760 C in a fluidized bed. 

Catalytic Cracking Test. A standard microactivity test (MAT) was used to evaluate the conversion and selectivity of catalyst samples. The tests were done at the University of Pittsburgh s Applied Research Center (former Gulf Research Laboratory), a qualified laboratory for MAT evaluations. A standard method, developed by Gulf, was used without modification. A Cincinnati gas oil was cracked under the following conditions cat/oil=3, 16 h 1 WHSV, and 516°C. Prior to charging the reactor, all samples underwent a standard thermal pretreatment. Solids were first heat shocked for 1 h at 593°C. Next, selected materials were impregnated with 3000 ppm Ni and 6000 ppm V, as naphthenates. Then all samples were calcined for 10 h at 538°C. Finally, each material was steamed at 732°C for 14 h in a fluidized bed to produce a catalyst in a simulated equilibrium state. 

Catalysts are manufactured by various methods (such as precipitation, extrusion and spray drying) in the form of cylinders, rings, multi-lobed extru-dates and other shapes. They range in size from a few millimetres to several centimetres small spheres are used in fluidized bed reactors. Active phases can be dispersed on the pre-shaped support by several methods such as by impregnation of a solution of the active components. Alternatively the catalysts can be made by the extrusion of mixtures of solid components the support, active phase, and binder. For some reactions that are diffusion limited, the catalyt-ically active species are not uniformly distributed instead they are deposited on the outer shell of the catalyst particle (egg-shell catalysts), since those inside the particle cannot be involved in the reaction. 

In a column (such as a packed or fluidized bed) reactor, the reaction conversion is often limited by the diffusion of rcactani(s) into the pores of the catalyst or catalyst carrier pellets or beads. On the other hand, when the catalyst is impregnated or immobilized within membrane pores, the combination of the open pore path and the applied pressure... 

Supported bis(triphenylsilyl) chromate is widely used as a low-activity substitute for chromium oxide in fluidized-bed reactors with gas-phase reactants. To generate sufficient activity, it is necessary to add an organoa-luminum compound (e.g., AlEt3 or AlEt2OEt) to reduce and alkylate the catalyst. The aluminum alkyl is usually impregnated onto the silica-supported bis(triphenylsilyl) chromate. These catalysts usually provide a broader MW distribution than simple catalysts made from chromium oxide on silica, and the two types are often contrasted with each other [150]. Elowever, catalysts made from chromium oxide on silica can be similarly impregnated with such cocatalysts (Section 17) and they then produce the same broad MW distribution [155-159]. 

In Chapter 2 we discussed a number of studies with three-phase catalytic membrane reactors. In these reactors the catalyst is impregnated within the membrane, which serves as a contactor between the gas phase (B) and liquid phase reactants (A), and the catalyst that resides within the membrane pores. When gas/liquid reactions occur in conventional (packed, -trickle or fluidized-bed) multiphase catalytic reactors the solid catalyst is wetted by a liquid film as a result, the gas, before reaching the catalyst particle surface or pore, has to diffuse through the liquid layer, which acts as an additional mass transfer resistance between the gas and the solid. In the case of a catalytic membrane reactor, as shown schematically in Fig. 5.16, the active membrane pores are filled simultaneously with the liquid and gas reactants, ensuring an effective contact between the three phases (gas/ liquid, and catalyst). One of the earliest studies of this type of reactor was reported by Akyurtlu et al [5.58], who developed a semi-analytical model coupling analytical results with a numerical solution for this type of reactor. Harold and coworkers (Harold and Ng... 

Scheme 9. BP preparation of fluid-bed catalysts by impregnation of a fluidizable support... 

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