Methane carbonaceous material

At Brookhaven National Laboratory in the 1980s, a two-step process was described for the coproduction of hydrogen and carbon, with methane being the intermediate see Steinberg.107108 In the first step, carbonaceous material is hydrogasified to methane with a subsequent thermal decomposition of the methane to hydrogen and carbon. In the process, water is also formed from the oxygen present in the fuel. A typical overall conversion of biomass, as reported by Milne et al.,5 would be... 

D. Lozano-Castello, J. Alcaiiiz-Monge, M. A. Casa-Lillo, D. Cazorla-Amoros, and A. Linares-Solano, Advances in the study of methane storage in porous carbonaceous materials, Fuel, 81, 1777-1803 (2002). 

Chung HM, Sackett WM (1979) Use of stable carbon isotope compositions of pyrolyticaUy derived methane as maturity indices for carbonaceous materials. Geochim Cosmochim Acta 43 1979-1988... 

The composition of the synthesis gas, particularly the concentrations of hydrogen, carbon monoxide, and carbon dioxide, affects the atmosphere throughout the reactor directly, and also indirectly by its effect on the composition of the recycle gas. Synthesis gas, prepared by partial combustion of methane or some less hydrogen-rich carbonaceous material, lacks sufficient hydrogen for the conversion of all the carbon monoxide to hydrocarbons, and in this sense the synthesis gas is deficient in hydrogen. Stoichiometrically methane has sufficient hydrogen to convert all its carbon to olefins by the two-step process ... 

A gasifier is used to produce synthesis gas from carbonaceous material. The solid is packed in a column, and gas is passed up through the bed, producing a mixture of combustible products, primarily methane, hydrogen and carbon monoxide, with a low to medium BTU content. 

Nanoporous carbonaceous materials are appropriate containers for storing molecules under strong confinement [196-207], In the case of the physical adsorption of methane with carbonaceous nanoporous materials, the attractive adsorption forces are only dispersive, therefore very weak hence, efficient carbonaceous materials for methane storage should have the highest possible specific surface areas and pore volume. However, the factor area is just not enough to get an efficient material, that is, the sizes of the pores are significant, especially when adsorption of a supercritical gas is concerned... 

The study of methane adsorption on activated carbon fibers has demonstrated, as was previously explained, that these carbonaceous materials, because of their cylindrical morphology and smaller diameter, have higher packing density than activated carbons with similar micropore volumes [191]. Subsequently, the higher adsorption capacity for the powdered activated carbons against the higher packing density for the fibers helps both kinds of materials reach similar, maximum adsorption values [191]. 

To conclude this section, widespread consensus exist that the adsorbents with the highest methane capacity are the carbonaceous materials, especially activated carbons [192], where storage values up to 200 v/v have been reported [213],... 

Early on the subsurface coal mining industry learned that swamp gas or firedamp was prevalent in underground coal mines. The gas is largely methane formed from the decay and rotting of carbonaceous materials to ultimately form coal. When pressure is released (as by drilling into the coal seam) the methane-rich gas migrates to the low pressure and is produced. The composition and properties of several coal bed methane streams are shown in Fig. 20.2.15... 

XPS and FTIR have been used for surface characterization in order to prove the formation of carbonaceous material on the NaP-modified MnOx catalyst surface. The results obtained offer clear evidence about formation of hydrocarbon deposits on the catalyst surface during the methane treatment. XPS showed a carbon line at 285 eV, whose intensity increased with a longer treatment in methane, this suggests that the amount of the carbon deposit increased. Intensity of Auger Na(KLL) line at ca. 264 eV was used as reference, since both ESCA and AFM studies showed that the surface of NaP particles remained uncovered by coke for a longer time than the manganese oxide surface The fine structure of the XPS line of C Is... 

After exposure to methane the IR spectra of manganese oxide showed absorption bands, which are characteristic of the C-H stretching vibrations (CHs 2962, 2872 cm CH2 2926, 2853 cm and CH 2890 cm ) [9]. The intensity of the C-H bands increased, if the exposure time to methane increased (Figs. 2,3). The intensity of the band at 1050 cm, which is assigned to V3(Si-0) of silica was used as an internal reference (Fig. 2). the intensity ratio for the CH2 and CH3 groups estimated for samples after 30 min reaction with methane, was found to be about five [10]. Thus XPS and FTIR surface analysis showed that carbonaceous material formed on the MnOx catalyst surface consists of CHx hydrocarbon deposits and manganese carbide species. 

At temperatures above 250-300°C, nickel catalysts cause extensive d radation of hydrocarbons with the formation of methane and hydrogen and the deposition of carbonaceous materials on the catalyst surface. However, on combining a hydrogenation catalyst such as nickel with a cracking catalyst such as silica-alumina so that the final catalyst contains 4-6 per cent by weight of nickd, a complex catalyst results which is quite active and... 

Coal, being largely composed of carbonaceous material, can also catch fire, in some cases spontaneously (Chapter 14). Coal, for the miner, has not been an attractive occupation. Interestingly though, the problem of methane may in the future become a profitable by-product from closed coal mines. Many countries are reported to millions of cubic feet of coal bed methane (CBM) trapped in abandoned coal mines. 

Hydrogasification Reaction of carbonaceous material such as coal with hydrogen to produce methane. 

Total organic carbon (TOC) analysis is based on the principle that carbon in an aqueous sample is converted to carbon dioxide by catalytic combustion or wet chemical oxidation. The carbon dioxide formed is measured directly by an infrared detector or converted to methane and measured by a flame ionization detector. The amount of carbon dioxide or methane is directly proportional to the concentration of carbonaceous material in the sample. Inorganic carbon is removed by acidification of the sample prior to analysis. 

It was half a century later that Gilliland and coworkers at Standard Oil rediscovered the looping principle and applied it for the production of synthesis gas [8] and the production of pure CO2 using Cu as the preferred carrier material [9]. It is noteworthy that the inventors already pointed out the fuel flexibility of the process (claiming broadly the use of oxidizable carbonaceous material and mentioning specifically hydrocarbons, methane, and coke). However, the process was not further pursued at the time, presumably due to lack of market demand. 

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