Catalysts hydrogen factor

When the hydrogen pressure is 1 atm, and the temperature is 77 °K, the experimentally observed (apparent) rate constant is 0.159 cm3/ sec-g catalyst. Determine the mean pore radius, the effective diffusivity of hydrogen, and the catalyst effectiveness factor. 

Hydrogen factor. This is a relative number proportional to the specific hydrogen yield, defined as specific H2 = H2 yield (100-conversion)/conversion. The hydrogen factor depends on the catalyst quality and is affected by nickel deposited on an equilibrium... 

This indicates that cos GhjO increases with the increase in oxygen content and decreases with the decrease in hydrogen content. This relationship was confirmed by the results of Kinoshita et al. [94] on the electrochemical treatment of carbon blacks. Hydrophilic carbons provide high catalyst utilization factors, whereas hydrophobic carbons (or graphitized carbons) allow easy water removal, avoid flooding of the CLs, and ensure better resistance to corrosion [8,96,97]. 

In the hydrogenation of oc-methylstyrene, varying degrees of catalyst effectiveness factors t] were found ... 

FIGU RE 23.13 Catalyst effectiveness factor vs. mole fraction of hydrogen in the bulk for low activity catalyst at a temperature of 295 K. Lines represent the model predictions of Jaguste and Bhatia (1995), points represent experimental data of Kim and Kim [4]. Numbers in parentheses indicate the percent liquid Idling of the pore structure. (From Jaguste, D.N. and Bhatia, S.K., A.I.Ch.E.J., 37, 650-660, 1991. With permission.)... 

Finally, when a membrane reactor was employed in open architecture configuration along with a catalyst effectiveness factor of 0.6, the hydrogen recovery factor was evaluated as a function of the membrane permeation surface. The results are shown in Fig. 11.6. 

Simulation of tubular steam reformers and a comparison with industrial data are shown in many references, such as [250], In most cases the simulations are based on measured outer tube-wall temperatures. In [181] a basic furnace model is used, whereas in [525] a radiation model similar to the one in Section 3.3.6 is used. In both cases catalyst effectiveness factor profiles are shown. Similar simulations using the combined two-dimensional fixed-bed reactor, and the furnace and catalyst particle models described in the previous chapters are shown below using the operating conditions and geometry for the simple steam reforming furnace in the hydrogen plant. Examples 1.3, 2.1 and 3.2. Similar to [181] and [525], the intrinsic kinetic expressions used are the Xu and Froment expressions [525] from Section 3.5.2, but with the parameters from [541]. 

Figure 3.23 Hydrogen plant. Temperature approach to equilibrium and catalyst effectiveness factors.

Whenever hydrogen halide is evolved, and whenever hydrogen halide is used as a reactant or as a catalyst, the factor relating to the solubility of the hydrogen halide is of considerable significance. 

The support basicity was found to be the major factor influencing the nickel catalyst hydrogenation properties (Fig. 2). The activity of nickel catalysts in toluene hydrogenation decreased with increasing number of basic sites. 

The mechanism and rate of hydrogen peroxide decomposition depend on many factors, including temperature, pH, presence or absence of a catalyst (7—10), such as metal ions, oxides, and hydroxides etc. Some common metal ions that actively support homogeneous catalysis of the decomposition include ferrous, ferric, cuprous, cupric, chromate, dichromate, molybdate, tungstate, and vanadate. For combinations, such as iron and... 

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