Hydrogen/carbon ratios, variation with

H/C = atomic hydrogen-to-carbon ratio V = vitrinite content of coal VM volatile matter St = total sulfur TRM = total reactive macerals The adequacies of these reactivity correlations, expressed as a percentage of the total variation in the data set explained by the model, were 80.0%, 79.2%, and 47.5% respectively. A later paper in the series (21) concentrated on the development of reactivity correlations for a set of 26 high volatile bituminous coals with high sulfur contents, and extended the models previously developed in include analyses of the liquefaction products and coal structural features. These structural features included the usual... 

These observations can be put on a more chemical basis by examining the variation of AHpp with the atomic hydrogen-to-carbon ratio (Figure 4). Here, the clustering of exinite properties is even more prominent. The single deviant exinite point comes from a very different organic matter type—alginite, rath-... 

The reformer takes an input flow rate of methane and computes the hydrogen output. The reformer module balances energy by combusting the reformate stream with air and exchanging the heat released to the catalyst reactor. Parameters on the reformer are the steam-to-carbon ratio and the outlet temperature of the exhaust products from the internal burner. The temperature at which the equilibrium reforming occurs depends on these parameters. Figure 1 shows the variation in thermal efficiency of the reformer with temperature and steam-to-carbon ratio. The minimum steam-to-carbon ratio is 2 however, reformers are often operated with excess steam to improve the efficiency and prevent coking problems. 

The nature of the substituent directly attached to the N-atom influences the properties (basicity, reduction potential, etc.) of the C=N function more than the nature of the substituents at the carbon atom. For example, it was found that the Ti-ebthi catalyst (Fig. 1) can hydrogenate only hf-alkylimines but not N-arylimines [6]. Oximes and other C=N-X compounds show even a more pronounced variation in their reactivity. The following sections give a short summary of the results obtained for different classes of C=N groups. Only catalysts with synthetically useful selectivities or otherwise of interest were included in Tables 2, 3, 4, 5, and 6 (s/c substrate/catalyst ratio, tof turnover frequency at high conversion). 

Carbon laydown increases as the hydrogen-to-hydrocarbon ratio (HHCR) decreases.47 The variation of ageing rate with HHCR is very steep for HHCR < 10 molar (Fig. 6.5).27 Lowering the Weight-Hourly Space Velocity (WHSV) at constant HHCR increases carbon laydown.47... 

The soft (chloroform-extractable) and hard coke fractions fi om a suite of deactivated Co/Mo hydrodesulfurisation (HDS) catalysts with carbon contents ranging from 5 to 18% have been characterised. The hard coke accounted for between 50 and 70% of the total carbon, but was responsible for much less of a reduction in BET surface area as the carbon content increased. Indeed, significant variations in hard coke structure were revealed by solid state C NMR with the aromaticity ranging from 0.6 to over 0.9 with increasing carbon content and time on stream. The relatively high aliphatic contents and atomic H/C ratios for the hard cokes obtained at low levels of carbon deposition (5-7%) suggested that much of the carbon should be removed under reductive conditions. Indeed, hydropyrolysis, in which the deactivated catalysts were heated from ambient to 500°C under a hydrogen pressure of 15 MPa, removed over 90% of the carbon and recovered 70% of the BET surface that had been lost. 

Determine the equilibrium composition that is achieved at 300 bar and 700 K when the initial mole ratio of hydrogen to carbon monoxide is 2. You may use standard enthalpy and Gibbs free energy of formation data. For purposes of this problem you should not neglect the variation of the standard heat of reaction with temperature. You may assume ideal solution behavior but not ideal gas behavior. You may also use a generalized fugacity coefficient chart based on the principle of corresponding states as well as the heat capacity data listed below. 

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