Catalysts in reactors

Because there are many different ways to combine a catalyst with a membrane, there are numerous possible classifications of the CMRs. However, one of the most useful classifications is based on the role of the membrane in the catalytic process we have a catalytically active membrane if the membrane has itself catalytic properties (the membrane is functionalized with a catalyst inside or on the surface, or the material used to prepare the membrane is intrinsically catalytic) otherwise if the only function of the membrane is a separation process (retention of the catalyst in reactor and/or removal of products and/or dosing of reagents) we have a catalytically passive membrane. The process carried out with the second type of membrane is also known as membrane-assisted catalysis (a complete description of the different CMRs configurations will be presented in a specific chapter). 

Vc = volume of catalyst bed in reactor, including voids and Wc = weight of catalyst in reactor. 

Estimated from a space velocity range of 0.5-3.0. Space velocity here is defined as (weight of oil feed per hour)/(weight of catalyst in reactor), since catalyst volume is not fixed in the fluid bed mode of operation. 

Type of catalyst Mass of catalyst in reactor, g Pressure, psig Flow rate, cm /sec (measured at 0°C, 1 atm) Mole fraction p-Hj in exit gas, (.Vj,)2... 

Table 4.2. Activities and selectivities for the hydrogenation of buta-1,3-diene to butenes of catalysts derived from amorphous and crystalline copper-zirconium alloys [4.50], The experiments were performed under the following conditions 403 K, total surface area of catalyst in reactor 0.066 +0.003 m2, total pressure 180 kPa partial pressure ratio butadiene hydrogen = 1...

Related topics include the use of ion exchange resins as catalysts in reactors (Section 16.11.6.32), liquid-solid fixed bed reactors (Sections 16.11.6.14 and 16.11.6.15), and adsorption-liquid (Section... 

The apparatus was later modified so that the products from reactor 1 passed through a cooling coil to trap hydrocarbons greater than Cg. The remaining products were passed over the tungsten oxide catalyst in reactor 2. The product distribution was that which would be expected from isomerization alone, with little cracking, and the lifetime of the catalyst was much greater. 

FIGURE 51.10 Transients for the isotopic variants of ethane (closed markers) and ethene (open markers) at weight of catalyst in reactor bed (W) to molar flow of CO (F) ratio (W/F) = 16.8 kgcat s/mol (A) and W/F = 44.8 kgcat s/mol (B). Other experimental conditions are presented in Reference [19]. 

Figure 29 The influence of average residence time of catalyst in reactor on the selectivity of ethylene and propylene. Reaction conditions 7=500 °C catalyst inventory=1 kg, WHSV=2 h water MeOH = 20 80, and gas-solid contact time =1.3 s.

The characteristic of this process is that several processes are parallel or cross-carried out i.e., the reduction process for the each catalyst particle proceeds from surface to core step-by-step and the reduction process of whole catalyst in reactor (bed) proceeds from the top (outside) down (internal) step by step, and also reaction process of H2 with N2 forms ammonia on reduced catalysts. Therefore, temperature (t) of catalyst bed, the reduction degree (i ) of catalyst and water vapor concentration (y>) are changing. Trends of different types of reactors at different reduction stages are shown in Fig. 5.26. 

Uniform coke content of catalyst in reactor, (Cc)o =10 wt-% Bed void fraction at minimum fluidization, Snif = 0.55 Flow rates = 2000 tons/h = 200 tons/h Wlihco = 0.77 h... 

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