Carbon, combustion

Cast analysis of carbon is not appropriate for Type I. Sheet products analysis is appropriate for checking proper type of material. Extremely low carbon levels can be checked accurately usiag carbon-combustion chromatographic-type analy2ers. 

When one considers the potential high-energy release on rupture of a carborane unit, together with the thermodynamic stability of combustion products, it is hardly surprising that there is a body of literature that reports on the use of carbo-ranes within propellant compositions. Their use in energetic applications is to be expected when the enthalpy of formation (AH/) data for the products of combustion for boron are compared to those of carbon. Thermodynamic data for the enthalpy of formation of o-carborane and of typical boron and carbon combustion products is shown in Table 4. Measurements of the standard enthalpy of combustion32 for crystalline samples of ortho-carborane show that complete combustion is a highly exothermic reaction, AH = — 8994 KJmol. ... 

Contemporary Carbon Combustion Source Contributions to Urban Air Particulate Levels Using C-14 Measurements, to be published in Env. Sci. Tech., 1981. 

Fig. 28. The cumulative COj/CO ratio for coke bum-off on spherical catalyst beads versus combustion temperature in air (O) white amorphous silica-alumina ( ) green Cr02-containing amorphous silica-alumina (M) macroporous white catalyst. The weight (mg) of the bead tested is denoted by the numerals adjacent to the respective symbol. Dashed line represents intrinsic ratios from carbon combustion research. From Weisz (1966).

These carbon residues then can be burned with air in the second stage of combustion. There are two modes of carbon combustion, with and without flames. If there is no flame over the carbon, then reaction occurs by surface reaction. 

The particle injection studies also indicated that lead sulfate alone was more harmful than lead oxide or lead chloride, suggesting that in the absence of catalytic activity on carbon combustion, higher melting compounds are more harmful than materials of lower melting point. Flakes of iron oxide from a corroded exhaust valve and bits of ceramic material from a broken spark plug insulator are very potent sources of surface ignition... 

Isochoric Flame Temp, K,T Force,ft-lbs/lb,xlCT F v Unoxidized Carbon,% Combustibles,%... 

Fixed carbon combustible residue (other than ash) left after the volatile matter is driven off generally represents the portion of coal that must be burned in the solid state predominantly carbon but may contain appreciable amounts of sulfur, hydrogen, nitrogen, and oxygen (ASTM D-3172). 

H. L. Riley, Chemical and Crystallographic Factors in Carbon Combustion,... 

Carbon Combustion Efficiency (Selection of Coal Feed Diameter)... 

The above simplified analysis was intended to provide a feel for the relative importance of the processes that govern carbon loading, and therefore carbon combustion efficiency. More complete treatments of AFBC s are available which consider the detailed population balance equations for the char particles coupled with an oxygen balance (41-50). These treatments have given results which parallel observations on operating AFBC s but... 

Combustion rate of carbon. Combustion of spheres in flowing gas streams. Ind. Eng. Chem., 26 749-757. 

Carbon combustion reaction is first order and the rate of reaction is the rate controlling step. 

Component Moisture matter Fixed carbon combustible As collected Dry and ash-free... 

The first term of Eq. 80 represents the mass loss of char particles due to carbon combustion and the second term represents the mass loss of char particles due to sulfur reaction with oxygen. Using the stoichiometry of reactions 1 and 2, we can obtain the moles of oxygen used up in these respective reactions for any arbitrary height n as. 

There are two more quantities that must be defined to complete the description of the fluidized bed combustor viz., the carbon combustion efficiency, ncCE> sulfur absorption efficiency, nsAE- These are ... 

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