Methane production

U.S. capacity for producing biofuels manufactured by biological or thermal conversion of biomass must be dramatically increased to approach the potential contributions based on biomass availabiUty. For example, an incremental EJ per year of methane requires about 210 times the biological methane production capacity that now exists, and an incremental EJ per year of fuel ethanol requires about 14 times existing ethanol fermentation plant capacity. 

Fig. 9. Methane production by pyrolysis using sand and char recycle in fluidized two-bed system.

An estimate of the potential methane production possible from existing (ca 1992) municipal wastewater treatment plants that produce and use... 

Table 37. Potential Methane Production from Commercial U.S. Anaerobic Digestion Systems...

Prior to methanation, the gas product from the gasifier must be thoroughly purified, especially from sulfur compounds the precursors of which are widespread throughout coal (23) (see Sulfurremoval and recovery). Moreover, the composition of the gas must be adjusted, if required, to contain three parts hydrogen to one part carbon monoxide to fit the stoichiometry of methane production. This is accompHshed by appHcation of a catalytic water gas shift reaction. 

A low calorific value gas, which includes nitrogen from air, could be produced for boiler or turbine use in electric power production, or an intermediate calorific value gas containing no nitrogen for an industrial fuel gas, or synthesis gas for chemical and methane production could be provided. This approach which has been studied in Russia, Europe, Japan, and the United States, is stiU noncommercial in part because it is not economically competitive. 

Some of these compounds could be considered as dietary additives, but various other terms, including pesticides, can also be used. They can have beneficial effects on the environment and this aspect will be discussed later. The ionophore monensin, which is an alicyclic polyether (Figure 1), is a secondary metabolite of Streptomyces and aids the prevention of coccidiosis in poultry. Monensin is used as a growth promoter in cattle and also to decrease methane production, but it is toxic to equine animals. " Its ability to act as an ionophore is dependent on its cyclic chelating effect on metal ions. ° The hormones bovine somatotropin (BST) and porcine somatotropin (PST), both of which are polypeptides, occur naturally in lactating cattle and pigs, respectively, but can also be produced synthetically using recombinant DNA methods and administered to such animals in order to increase milk yields and lean meat production. "... 

Methane production [CO2 + H2 (or simple organic compound such as acetate) - CH4 + H2O] Methane-producing bacteria... 

Then the activation energy for methane production from Cads is the overall activation energy for the hydrogenation of Cads to CH4, and Eq. (1.5) gives the rate of methane production ... 

We now study the consequences of these BEP choices to the dependence of predicted rate of methane production on Eads- Making the additional simplifying assumption that the adsorption energy parameters in Eqs. (1.9b) and (1.9c) are the same, one finds for the rate of methane production an expression... 

Recently, anaerobic filter process has been widely used for the treatment of various waste-waters because of several advantages over aerobic process such as lower nutrient requirement, less surplus sludge production, and energy recovery via methane production [1]. Although many types of anaerobic filter process have already been successfully commercialized, the details of their complicated process dynamics are still challenging issues to be clarified for their stable operations. 

A methanogenic bacterium was isolated from oil reservoir brines by enrichment with trimethylamine. Methane production occurred only with trimethyl-amine compounds or methanol as substrates. Sodium ions, magnesium ions, and potassium ions were all required for growth. This organism appears to be a member of the genus Methanohalophilus based on substrate utilization and general growth characteristics [695]. 

Treating a coal seam with a well treatment fluid containing a dewatering agent will enhance methane production through a well. This additive enhances the permeability of the formation to water production and binds tenaciously to the coal surface so that the permeability-enhancement benefits are realized over a long production term. 

W. M. Harms and E. Scott. Method for stimulating methane production from coal seams. Patent US 5249627,1993. 

K. H. Nimerick and J. J. Hinkel. Enhanced methane production from coal seams by dewatering. Patent EP 444760,1991. 

Holtshausen, L., Chaves, A. V., Beauchemin, K. A., McGinn, S. M., McAllister, T. A., Odongo, N. E., Cheeke, P. R., and Benchaar, C. (2009). Feeding saponin-containing Yucca schidigera and Quillaja saponaria to decrease enteric methane production in dairy cows. /. Dairy Sci. 92, 2809-2821. 

Hickey, R.F., Vanderwilen, J., and Switzenbaum, M.S., The effects of organic toxicants on methane production and hydrogen gas levels during the anaerobic digestion of the waste activated sludge, Water Res., 21, 1417-1427, 1987. 

Belle Glade Carbonate Hot acid Organic plant wastes Neutralization Bacterial sulfate reduction Methane production... 

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