Carbon Monoxide Fluxes

The total flux of CH4 to the atmosphere today is about 34 x 1012 moles y1 about 20% of this flux results from enteric fermentation processes in animals, termites, and humans. Of the remaining flux, about 60% comes from the process of methanogenesis in sediments of various types-primarily muds of rice paddy fields, swamps, and marshes. The overall bacterial reactions in sediments are the disproportionation of organic matter to CH4 and CO2, that is  

The main sink for methane in the atmosphere is oxidation by OH radical to carbon monoxide, which in turn is oxidized to carbon dioxide according to the reaction scheme first proposed by Levy (1971) and McConnell et al. (1971)  

Reaction of CH4 with OH accounts for the destruction of 76% of the methane flux to the atmosphere. Other sinks of tropospheric methane are shown in Table 9.2. 

The main source of carbon monoxide, aside from the fossil fuel burning flux, is ffom oxidation of CH4 (Table 9.3). The remainder comes ffom decomposition of organic matter in soils, and bacteria and algae in the ocean that actively generate CO from respiration processes according to  

The release of carbon monoxide ffom fossil fuel burning, principally from transportation sources, is currently about 28 x 1012 moles Cy1. The residence 

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D.J. Erickson (1989). Ocean to atmosphere carbon monoxide flux Global inventory... 

Sanhueza, E. Donoso, L. Scharfife, D. Cmtzen, P.J., 1994 Carbon Monoxide Fluxes from Natural, Managed, or Cultivated Savannah Grasslands , in Journal of Geophysical Research, 99 16421—16425. 

The sihcates formed in reactions 2 and 3 fuse with the added fluxes to form a Hquid slag at which point carbon monoxide loses its effectiveness as a reducing agent. Unreacted carbon from the fuel then becomes the predominant reductant in reducing both staimous siUcate to tin and ferrous siUcate to iron. The metallic iron, in turn, reduces tin from stannous siUcate ... 

Figure 10. Yield of Carbon Monoxide as a Function of Halon Concentration for the Fiber Reinforced Composite Materials. External Heat Flux of 60 kW/m2 in Normal Air was Used in the Experiments.

HIsmelt A direct iron smelting process in which noncoking coal, fine iron ore, and fluxes and gases, are injected into a molten iron bath the carbon monoxide produced is used to prereduce the ore in a fluidized bed. Under development by CRA, Australia, since the early 1980s, joined by Midrex Corporation in 1988. Their joint venture company, Hismelt Corporation, commissioned a pilot plant at Kwinana, near Perth, Australia, in 1993. 

Phosphorus is manufactured by the reduction of commercial-quality phosphate rock by coke in an electric furnace, with silica used as a flux. Slag, ferrophosphorus (from iron contained in the phosphate rock), and carbon monoxide are reaction byproducts. The standard process, as shown in Figure 2, consists of three basic parts phosphate rock preparation, smelting in an electric furnace, and recovery of the resulting phosphoms. Phosphate rock ores are first blended so that the furnace feed is of uniform composition and then pretreated by heat drying, sizing or agglomerating the particles, and heat treatment. 

Here iii " and mout denote the mass flow rate of the mixture entering from the inlet and leaving from the outlet respectively. Rate of consumption and rate of production of each species A is denoted by m sed and mv d. These rates include the flux of reactants, which take part in electrochemical reactions, across the chan-nel/electrode interfaces and also the consumption and production of species due to methane reforming reaction on the anode side. Both hydrogen and carbon monoxide electrochemistry was considered and it was assumed that n2, the fraction of the current that is produced from H2 oxidation, is known. Thus the specie consump-... 

Table 9.3. Global carbon monoxide sources and sinks fluxes in units of 1012 moles C y1. (After Seiler, 1974.)...

Comparison of carbon monoxide yield for PA6-based materials at different heat fluxes. 

The cooled yellow solution can be left overnight under a small flux of carbon monoxide and then allowed to react with Zn without any apparent variation in the yields of the product. However, the checkers note that the solution becomes cloudy on standing overnight under CO. 

The important reactions which occur in the blast furnace are the combustion of coke to carbon monoxide, the reduction of iron oxide by the carbon monoxide, and the combination of acidic and basic oxides (the impurities of the ore and the added flux) to form slag ... 

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