Typical Catalyst Composition

A more active bismuth phosphomolybdate (Table 4.13) was prepared simply by adding an appropriate volume of phosphoric acid to the initial solution. A typical catalyst composition was claimed to be Bi9PMoi2052-55 2Si02. The same catalysts could be used to produce both acrolein and acrylonitrile. 

C, 0.356—1.069 m H2/L (2000—6000 fU/bbl) of Hquid feed, and a space velocity (wt feed per wt catalyst) of 1—5 h. Operation of reformers at low pressure, high temperature, and low hydrogen recycle rates favors the kinetics and the thermodynamics for aromatics production and reduces operating costs. However, all three of these factors, which tend to increase coking, increase the deactivation rate of the catalyst therefore, operating conditions are a compromise. More detailed treatment of the catalysis and chemistry of catalytic reforming is available (33—35). Typical reformate compositions are shown in Table 6. 

A few industrial catalysts have simple compositions, but the typical catalyst is a complex composite made up of several components, illustrated schematically in Figure 9 by a catalyst for ethylene oxidation. Often it consists largely of a porous support or carrier, with the catalyticaHy active components dispersed on the support surface. For example, petroleum refining catalysts used for reforming of naphtha have about 1 wt% Pt and Re on the surface of a transition alumina such as y-Al203 that has a surface area of several hundred square meters per gram. The expensive metal is dispersed as minute particles or clusters so that a large fraction of the atoms are exposed at the surface and accessible to reactants (see Catalysts, supported). 

Effect of Catalyst Composition. Where acetic is the typical acid substrate, effective ruthenium catalyst precursors include ruthenium(IV) oxide, hydrate, ruthenium(III) acetyl-acetonate, triruthenium dodecacarbonyl, as well as ruthenium hydrocarbonyls, in combination with iodide-containing promoters like HI and alkyl iodides. Highest yields of these higher MW acids are achieved with the Ru02-Mel combination,... 

The supported Cu/Ce02 catalyst (denoted here as Cu/Ce-CTAB) was hydrother-mally prepared using Ce and Cu nitrates as precursors with a surfactant, CTAB [90], In a typical synthesis method, Ce(N03)3 6H20 was dissolved in hot distilled water, to which Cu(N03)2 3H20 in H20 was added dropwise. Then, CTAB was dissolved in a mixture of H20 and ethanol, and the obtained solution was added to the Cu + Ce solution. The typical molar composition is Cu/CTAB/H20 = 1.0 0.55 325. The homogeneous slurry mixture was hydrothermally treated at 175 °C for 24h in a Teflon-lined autoclave vessel under an autogeneous pressure. The resultant product was washed with distilled H20 and EtOH, and dried at ambient temperature for 10 h and then at 100 °C for 8h, followed by heating at 500°C for 6h under a He flow. The Cu contents of the obtained solid catalysts were determined by XRF. 

A simplified flowsheet for an ammonia plant that processes natural gas via steam reforming is shown in Figure 6.7. A block diagram of this same plant is shown in Figure 6.8. This diagram lists typical stream compositions, typical operating conditions, catalyst types (recommended by Synetix) and catalyst volumes82. 

The reaction takes place under fuel-rich conditions to maintain a nonflammable feed mixture. Typical feed composition is 13% to 15% ammonia, 11% to 13% methane and 72% to 76% air on a volumetric basis. Control of feed composition is essential to guard against deflagrations as well as to maximize the yield. The yield from methane is approximately 60% of theoretical. Conversion, yields, and productivity of the HCN synthesis are influenced by the extent of feed gas preheat, purity of the feeds, reactor geometry, feed gas composition, contact time, catalyst composition and purity, converter gas pressure, quench time and materials of construction. 

In principle, the SBA/Topspe process consists in mixing the burner exit gases with steam and sending the mixture to a fixed-bed reactor on a nickel base catalyst, at about 2.10 Pa absolute and about 950 C This technique, sometimes called partial catalytic oxidatioEu is only applied to the conversion of natural gas, LPG and naphthas, particularly because, if heavier feeds are used, problems arise in the prior separation of sulfur derivatives that cannot be t[Pg.42]

After the war, ARGF (Arbeitsgememschaft Ruhrehemie und turgi) developed the high-load fixed-bed process. The precipitated iron catalysts used consisted of Fe (100). SiOj (25), K2O (5). and Cu (5). The typical product composition obtained was 32% gasoline, 21 % diesel fuel, and 47% higher paraffins (wax) [3]. 

Catalyst Composition. Chemical compositions of typical nickel and cobalt zeolites are summarized in Table 1. Based on the total CEC derived from the initial sodium composition, 23 to 37% of the Zeolon and 8.4% of the Linde SK400 exchange sites are occupied by nickel cations. In Zeolon, 55% of the exchange sites are occupied by cobalt cations. A ratio of 1.41 1 for cobalt to nickel on the Zeolon exchange sites resulted where nickel and cobalt were exchanged under comparable conditions. 

Bulk (Unsupported) M0S2 and H 52- Promoted. The promoted catalysts display the phenomenon of synergy. The catalytic activity in hds and also in hydrogenation of olefines and aromatics is greater than the sum of the activities of the individual components and reaches a maximum value at a particular catalyst composition for both bulk and supported catalysts. An activity-composition plot is typically a volcano curve. The composition of the catalyst is expressed preferably as mole fraction of promoter (x = [M] / ([M] + [M ]) where M is the promoter and M is Mo or W. Synergy is discussed further in connection with supported catalysts in the following Section. 

Fig. 11 Schematic picture of the cathode catalyst layer and its composition, exhibiting the different functional parts. The typical catalyst layer thickness is l 10-20 pm.

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