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Gasification, coal equilibria

As in any gasification of coal the exothermic reaction of carbon with oxygen to CO (60) and C02 (Eq. 78) and the endothermic reaction with water (Eq. 61) run in parallel in different extent it seems to be often a mere semantic question whether to classify- a process as a partial oxidation or to use just the more general expression of coal gasification. Bouduard equilibrium (Eq. 46), water gas shift equilibrium (Eq. 37) and methane formation equilibrium (Eq. 71) are additional determinants... [Pg.107]

Two- and Three-Phase Equilibrium Calculations for Coal Gasification and Related Processes... [Pg.393]

Liu, S., Wang, Y., Yu, L. and Oakey, J. (2006) Thermodynamic equilibrium study of trace element transformation during underground coal gasification. Fuel Processing Technology, 87(3), 209-15. [Pg.299]

A tube-wall reactor, in which the catalyst is coated on the tube wall, is conceptually ideally suited for highly exothermic and equilibrium-limited reactions because the heat generated at the wall can be rapidly taken away by the coolant. Previous work (1) has numerically demonstrated that for highly exothermic selectivity reactions, the optimized tube-wall reactor is superior from both steady state production and dynamic points of view to the fixed-bed reactor. Also, the tube-wall reactor is being advanced as a possible reactor for carrying out methanation in coal gasification plants (2). From a reaction engineering point of view, it therefore seems appropriate to analyze the reactor for the analytically resolvable case of complex first-order isothermal reactions. [Pg.459]

Table 1 shows the equilibrium oxygen partial pressure of several metal oxides, i. e. the minimum oxygen partial pressure which is required for oxide formation. A comparison with Table 2, in which typical oxygen partial pressures of industrial processes are listed, clearly demonstrates, that in coal gasification processes and petrochemical plants stable oxide scales can only be expected on alumina formers. Chromia becomes unstable at the low oxygen partial pressures encountered in such processes. [Pg.203]

Modern chemical processing demands much better estimates of physical properties than in previous eras because the costs of excessive design are now often too great. High-pressure systems are of particular concern, and they are becoming more prevalent as in coal gasification and liquefaction and in Fischer-Tropsch syntheses. A weak link in estimation techniques for these systems is the vapor—liquid equilibrium distribution of components at temperatures well above the critical temperature of one or more of the species present and below the critical temperature of the others. [Pg.104]

This principle can be, and has been, applied to hi temperature gas mixtures. Specifically, the removal of H,S from fuel gas streams (natural gas and coal gasification product streams). Since the membrane is exposed to the same pressure on both sides, there is no theoretical limit to the pressure at which the process operates. Also, since there is no reaction or absorption equilibrium, there is no theoretical limit to removal. [Pg.536]

If a membrane is manufactured so as to be already in equilibrium with the gas to be treated, it will not have to undergo the stresses inherent in the density changes associated with sulfiding a carbonate membrane or carbonating a sulfide membrane. While techniques for manufacturing such a membrane are still imder study, the concept has been successfiiUy used in both the coal gasification process cell d and the natural gas process cell ... [Pg.539]

Fig. 5-6 Equilibrium composition of the product gas after steam-coal gasification as a function of temperature and (left) 0.1 MPa, (nght) 4 MPa, from [30]... Fig. 5-6 Equilibrium composition of the product gas after steam-coal gasification as a function of temperature and (left) 0.1 MPa, (nght) 4 MPa, from [30]...
Figure 10-31. Quasi-equilibrium gas-phase eomposition atthe gasification of low-quality coal as afunction of temperature (a) organic fraction (b) mineral fraction. In the figure, c volume fraetion of a eomponent, T, average temperature. Figure 10-31. Quasi-equilibrium gas-phase eomposition atthe gasification of low-quality coal as afunction of temperature (a) organic fraction (b) mineral fraction. In the figure, c volume fraetion of a eomponent, T, average temperature.

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See also in sourсe #XX -- [ Pg.278 ]




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Coal gasification

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