Methane increased production

Byproduced C02 in the DME reforming may be used for the methane increased production. 

After peroxide injection, conversion of methane increases fix)m -4% to -10%, methanol production increases 17 fold, and carbon dioxide increases 5 fold, along with modest increases in hydrogen and carbon monoxide. Introduction of hydroxyl radicals to the reactor leads to a greater fi action of product going to methanol as evidenced by methane conversion increasing 2.5 times, whereas methanol production increases 17 times. The increase in carbon dioxide is fiom "deep" oxidation of... 

If methanol utilization is to be increased, production needs to become more efficient and the infrastructure improved to make it more competitive. A major source of methane has been natural gas, since this has been the most economical source. Although the United States has both natural gas and coal, these are both nonrenewable resources. 

If the subsequent stage is at a lower temperature, carbon oxides and hydrogen recombine to methane, increasing the calorific value. Following C02 removal, very little enrichment is required lo achieve a product fully interchangeable with natural gas. 

Unlike the ethane case where the use of hydrogen as furnace fuel greatly reduces the carbon emissions in the CLOSED system, the lower hydrogen production and increased production of methane results in only a small lowering of emission intensity relative to the OPEN system. 

Hydrogen production by partial oxidation from methane increases with process temperature, but reaches a plateau value at around 1000 K (Fukada et ah, 2004). The theoretical efficiency is similar to that of conventional steam reforming, but less water is required (Lutz et ah, 2004). 

The behaviour of CO2 in Fischer-Tropsch synthesis was investigated using a promoted iron and a promoted cobalt catalyst. The decrease in yield of hydrocarbons is more pronounced on cobalt than on iron. The product distribution on iron remains nearly constant with increasing CO2 concentration, however on cobalt the selectivity to methane increases dramatically. 

Methane is an ubiquitous trace gas found in all marine and freshwaters. Its concentration in the surface waters of the open ocean is near saturation (1-3), however in some near shore areas, in anoxic basins, and in marine sediments the concentrations are significantly higher (4, 7) because of increased production rates. The highest production rates of methane are usually restricted to anoxic environments, but significant rates of production also have been observed in oxic marine water columns (8, 9). 

An example of cross-shelf variations in water properties and their influence on the distribution of methane is shown in Figure 4 (see Figure 1 for the location of the vertical section). The estuarine character of the embayment is clearly shown by the distribution of salinity, where low salinity water at the surface moving seaward is being replaced by higher salinity water at depth. High concentrations of methane are evident in the bottom waters of St. George Basin (PL4-PL8) and are the result of increased production and stratification. 

The consumption of methane increases with the amount of methane in the gas phase. This consumption is strongly related to the production of C2 hydrocarbons and to the active sites able to generate methyl radicals, while the low production of CO2 suggests a shortage of active sites for the oxidation of methane to CO2. 

Evidently the 10 % Pb0/Si02 catalyst has a different nature than the two lower loading samples, in the sense that it has something that inhibits the deep oxidation of methane, increasing the generation of methyl radicals and so the production of C2 hydrocarbons. 

Figure 1 illustrates the selectivity-conversion relationship between the various products obtained at 550 and 600 °C, during these experiments. It can be clearly be seen that HCHO was a primary product. Indeed as conversion increased HCHO selectivity decreased, with an analogous increase in CO selectivity. Further increase in CH4 conversion lead to the onset of increased COj selectivity, indicating a sequential reaction from methane to products as follows ... 

One widely known example of such ineffective attempts is the direct oxidation of methane-to-methanol (DOMM) (see Arutyunov and Krylov, 1998 and literature cited therein). Whereas at atmospheric or somewhat higher pressures the introduction of catalysts (or homogeneous promoters) accelerates the process and increases product (mainly formaldehyde) yield to some extent, at increasing pressures their efficiency sharply drops. As a result, the methanol yield cannot be increased by any means above the level attainable in high-pressure homogeneous oxidation. 

Initially acetic acid desorbed unaltered. However, as the tenperature increased, products of thermal decomposition and further reaction were observed. At 240°C there was a large 002 peak, some ethene, methane, water and acetone. Integration of the desorption peaks, followed by scaling by their respective sensitivity factors, gave the following mole percentages of products desorbed CO2 39, ethene 15.4, H2O 25.8, CH4 9.9 and acetone 9.9. A mass balance of the C, 0 and H atoms evolved gave a ratio of C 0 H of 109 114 212, approximately the ratio for acetic acid (2 2 4). This implies that the products desorbed were from the decomposition of acetic acid only. This supports the hypothesis that acetic acid was sorbed intact (i.e. equation 2 rather them equation 1). If water had been eliminated upon sorption on an acid site then the desorption products could not include acetic acid, as any water evolved would have rapidly desorbed from the zeolite at 150°C. 

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