Hydrogen composition

Both empirical formulae have hydrogen compositions assigned to agree with the composition chosen based on other evidence. 

The amounts of exchange and addition were calculated from a hydrogen isotope mass balance of the coal products, donor solvent and gas phase hydrogen. The starting and product weights of the coal and hydrogen compositions of the coal and coal products are shown in Table IV. From the values in Table IV, the net amount of hydrogen added to the coal, H, is... 

Both vanadium and niobium metals form dihydrides only at high pressures(27), and numerous phases with hydrogen compositions less than one(28). Experiments were performed to saturate vanadium clusters with deuterium. Figure 4 is a plot of the number of deuteri urn molecules found in the products. The solid straight lines are for D V ratios of 1 and 2. The corresponding curved dashed lines include corrections for some bulk atoms(2c). The best fit to the data including only surface atoms indicate a stoichiometry of 1.5. It is likely that this high surface stoichiometry is an indication of bulk i ncorporation of deuterium. 

Hydrogen chloride-water-inorganic compound systems, 13 817-818 Hydrogen composite curves, 20 746, 747 Hydrogen compounds. See Hydrides Hydrogen content, determination of, 13 789-790... 

Fig. 22. Experimentally observed and simulated light-off curves for fresh NSRC. (a) CO oxidation, influence of lean (excess of 02) and rich (excess of CO) conditions. Composition of inlet gas (mol. fractions)—lean mixture 0.25% CO, 7% 02 rich mixture 0.25% CO, 0.05% 02. (b) C3H6 oxidation, influence of inhibition by NO. Composition of inlet gas (mol. fractions) 200 ppm C3H6, 0.25% CO, 7% 02 and 0 or 150 ppm NO. (c) Water gas shift—production of hydrogen, composition of inlet gas (mol. fractions) 4.2% CO, 0.0% 02. All gas mixtures 10% H20, 10% C02 and balance N2. Temperature ramp 3K/min (Koci et al., 2007b).

The x-ray data presented in Figure 9 permit an estimation of the hydrogen composition at the 0 = 7 phase boundary via determination of the lattice parameter of the bcc 0-phase obtained on samples examined in the two-phase region. These results are included in Table V. The accuracy of these data are sufficient to conclude that the composition of 0-max (i.e., the maximum hydrogen composition exhibited by the single 0-phase) decreases with molybdenum content. This result agrees qualitatively with the data presented in Figure 7. 

HYDROGEN COMPOSITION VERSUS FRACTION OF STOICHIOMETRIC OXYGEN... 

The hydrogen composition of subsurface gases has been measured in geochemical studies. The H2 gas component in the gas mixture must be separated chromatographically and detected using high sensitivity instruments. The concentration of H2, He, Ne, Ar, N2, and CH4 in gas samples can be directly determined under optimum conditions use of an 8 m column packed with a 60-80 mesh 5 A molecular sieve activated at 360 °C for 12 h, and the use of oxygen gas as the carrier gas. The determination limit for H2 is 10 mL with a preamplifier. 

The hydrogen composition remained unchanged at two percent (2%) in both catalyzed and noncatalyzed runs. Our results with potassium carbonate do not support this conclusion. 

There are a number of explanations that can be offered for the observed differences in the carbon and hydrogen compositions of these humic substances. One is that the substances extracted by the two solvents are significantly different. Another, and more likely, explanation is that some oxidation occurs during extraction with sodium hydroxide. Bremner (1950) has... 

Use a feedback loop which measures the recycled gas hydrogen composition to adjust the value of the hydrogen fresh feed rate (composition controller, CC1). 

Changes in the hydrogen composition of the fresh hydrogen stream This disturbance will affect the hydrogen composition of the reactor inlet stream. To eliminate its effect we can use the feedback composition controller, CC1, which was installed for material balance control. It measures the hydrogen recycle composition and adjusts the fresh hydrogen flow rate. 

Adjust the hydrogen makeup flow rate Fg. From eq. (25.3) of Table 25.2 we can see that Fa depends on yH2 (i.e., the value of the recycled gas composition in hydrogen), which must be maintained at 0.4 (see the assumptions resulting from process optimization in Table 25.1). Therefore, we can use a feedback controller which measures the hydrogen composition in the recycled gas and adjusts Fg in order to maintain yH2 = 0.4. 

Rate constants for carbon monoxide s adsorption, desorption, and irreversible surface binding (e.g., its chemisorption), at different hydrogen compositions, over the... 

Coke deposition is a potential problem in steam reformers, and is favored by low steam to carbon ratio and high temperatures. High hydrogen composition also lowers the potential for carbon deposition. The following three reactions can deposit solid carbon, and the thermodynamic equilibrium relationships for these reactions, when carbon is graphite, are well loiown. ... 

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