Hydrogasification yields

Table 18. Gas Composition and Yield from Integrated Hydrogasification Process at Stage T...

In general terms, as the molecular weight of the feedstock is increased, similar operating conditions of hydrogasification lead to decreasing hydrocarbon gas yields, increasing yields of aromatic Hquids, with carbon also appearing as a product. 

The hydrogasification reactor operates at pressures of 1000-1500 psig and at temperatures of 760°-982°C in order to obtain the proper reaction rates and yields of methane required for process optimization. About 50% of the feed carbon is converted to gases in the hydrogasifier. 

At the hydrogasification conditions used, about 90% of the 360°C endpoint feed oil is gasified, yielding a raw gas containing about 52% methane and 10% ethane, with the remainder principally hydrogen. About 60% of the liquid products is benzene. Total liquid products are removed... 

The concept is a dilute-phase hydrogasification process in which coal is directly reacted with hydrogen to produce maximum yield of methane in the reactor. We are not, as an organization, competitive with industry either in hardware or in process work. 

In this process, gasification is carried out in the presence of hydrogen. Most of the research on hydrogasification has targeted methane as the final product. One approach involves the sequential production of synthesis gas and then methanation of the carbon monoxide with hydrogen to yield methane. Another route involves the direct reaction of the feed with hydrogen (Feldmann et al,... 

D.S. Scott Hydrogasification of biomass to produce high yields of methane. U.S. patent 4,822,935, April 1989. 

Results and Discussion. In dilute-phase hydrogasification, the composition of the effluent gas is determined by the feed gas rate and composition and the gas yield. The feed gas rate and composition can be selected somewhat freely, but the gas yield depends on many variables, some of which interact. The most prominent variables are coal rate, hydrogen coal ratio, maximum temperature attained by the solids and the vapors, residence times of the solids and the vapors, total pressure, hydrogen partial pressure, particle size and density, gas viscosity, heat... 

Development of dilute-phase hydrogasification is continuing to determine the effect of higher coal temperatures on yields and gas composition. Coals other than Pittsburgh seam also will be tested. 

Catalysts. The catalysts used were commercial cobalt molybdate and a laboratory-prepared depleted uranium catalyst. The cobalt molybdate consisted of cobalt and molybdenum oxides on 6- to 8-mesh alumina granules. The uranium catalyst consisted of 7.7% depleted uranium (uranium from which the U-235 has been removed) in the oxide form on 1/8-in. H-151 alumina balls. This catalyst had produced high gas yields in previous hydrogenation experiments with shale oil, and these results suggested its possible use as a hydrogasification catalyst. Both catalysts were maintained under a hydrogen atmosphere at approximate reaction temperature and pressure for about 12 hours before each experiment. 

Results of our most recent FDP reactor operations are summarized in Table I and the analyses of the feed coals used are listed in Table II. The main objectives of these experiments were (1) to establish the feasibility of directly producing a high Btu gas by hydrogasifying raw coal in a continuous reactor at economical pressures, (2) to measure the yields and distribution of coal hydrogasification reaction products, and (3) to provide data for scaling up the FDP reactor. 

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