Hydrogen utilization

Changing process configuration to SRC-II was successful in producing about 50% additional oil. However, a large increase in light hydrocarbon gas make accompanied this increase with an attendant reduction in hydrogen utilization efficiency, and problems persisted using coals other than Kentucky 9/14. 

In very broad terms, hydrogenation activity in terms of hydrogen utilization increases as coal rank decreases. Thus, in the absence of any other information, one can expect WVGS 13423 to be the more reactive of the two Obviously, generalities about hydrogenation behavior should not be extended to other coals based solely on a limited data set. Nevertheless, important differences between the pitches derived from WVGS 13421 and WVGS 13423 are apparent. 

Poor hydrogen utilization results in less than optimal thermal efficiencies for all developing processes. 

Catalytic hydrogenation of aromatic compounds proceeds exothermically under atmospheric pressure, without addendum required for keeping the reaction conditions. In contrast to the other media such as compressed hydrogen and liquefied hydrogen, external heat should be provided toward organic chemical hydrides at the site of hydrogen utilization. 

It is to be noted that the difference in dissipation of energy between the thermal energy demanded by organic chemical hydrides and the mechanical energy by compression or liquefaction of hydrogen is quite significant because the former is supplied as waste heat, whereas the latter is lost at the site of hydrogen utilization for fuel cells or ICEs. 

In the previous decades, severe accidents have happened involving hydrogen utilized in industrial and other applications. The determinant causes for a catastrophic event may be classified into the following [13] ... 

Other methods of reducing the nitroso compound include the use of ammonium sulfide4 and hydrogenation utilizing Adams catalyst.5... 

Zehnder, A. J. B., B. A. Huser, T. D. Brock and K. Wuhrmann, 1980, Characterization of an acetate decarboxylating, non-hydrogen-utilizing methane bacterium. Archives of Microbiology 124, 1-11. 

The principles for hydrogen utilization systems are also discussed, and the frontier examples are introduced. 

The precious ways of hydrogen utilization have the principles based upon the two non substitutive properties of hydrogen, that is, hydrogen energy systems are not only ecological but also energetic. 

One of the local recycle systems (LRS) of hydrogen utilization is due to physical and reversible reaction as [19]... 

PEM fuel cells and chemical heat pump will be the new frontiers in the hydrogen utilization systems. However, if hydrogen protein can be biologically created, it will be a great gospel for mankind. 

B. Friedrich, E. Schwartz (1993) Molecular biology of hydrogen utilization in aerobic chemolithotrophs. Annu. Rev. Microbiol., 47 351-383... 

Improvement in hydrogen utilization from the reformate flow... 

Many synthetic applications of Rh-catalyzed hydrogenation of a-dehydroamino acid derivatives have recently been explored (Scheme 26.2). Takahashi has reported a one-pot sequential enantioseiective hydrogenation utilizing a BINAP-Rh and a BINAP-Ru catalyst to synthesize 4-amino-3-hydroxy-5-phenylpentanoic acids in over 95% ee. The process involves a first step in which the dehydroami-no acid unit is hydrogenated with the BINAP-Rh catalyst, followed by hydrogenation of the / -keto ester unit with the BINAP-Ru catalyst [87]. A hindered pyridine substituted a-dehydroamino acid derivative has been hydrogenated by a... 

More complicated expressions than those above can be used in the 0-D models, but these usually stem from a more complicated analysis. For example, the equation used by Ticianelli and co-workers comes from analysis of the catalyst layer as a flooded agglomerate. In the same fashion, eq 21 can be embedded and used to describe the polarization behavior within a much more complicated model. For example, the models of Springer et al. " and Weber and Newman " use a similar expression to eq 21, but they use a complicated 1-D model to determine the parameters such as ium and R. Another example is the model of Newman,who uses eq 22 and takes into account reactant-gas depletion down the gas channels by, in essence, having a limiting current density that depends on the hydrogen utilization. All of these types of models, which use a single equation to describe the polarization behavior within a more complicated model, are discussed in the context of the more complicated model. 

The reactor was tested using a range of methanol and water concentrations, and researchers found the best results using a water and methanol mixture with a steam-to-carbon ratio (S C) of 1.1 1. They were able to achieve 90% conversion at 260 °C with a reactant liquid flow rate of 12 cmYh. Assuming a fuel cell efficiency of 60% and 80% hydrogen utilization, they estimated the output power to be 15 W. Eventually the complete system will include a cata-... 

Reduced hydrocarbon gas make resulting in reduced feed gas consumption and enhanced hydrogen utilization efficiency... 

Smatlak, C. R., J. M. Gossett, and S. H. Zinder, Comparative kinetics of hydrogen utilization for reductive dechlorination of tetrachloroethene and methanogenesis in an anaerobic enrichment culture , Environ. Sci. Technol., 30, 2850-2858... 

Representative performances in steady states obtained to date are (i) a conversion of 5%, a selectivity above 90%, and hydrogen utilization efficiency of 35% and a STY (space-time yield) of 80-100 h 1 g-PO kg-cat-1 over Au/mesoporous Ti-Si02 and (ii) a conversion of 10%, a selectivity of 76% and a STY of 134h-1 g-PO kg-cat-1 over Au/microporous TS-1. 

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