Emissivities of Combustion Products

5-21 Spectral emittances for carbon dioxide and water vapor after RADCAL. pcL = pwL = 0.36 atm-m, Tg = 1500 K. 

---

The use of cokes as fuels, or the heating of crucibles and furnaces with gas or oil-fired burners can cause emissions of combustion products, such as NOx and SO2. Additionally, the use of cokes and the presence of impurities (e g. oil, paint,. . . ) in scrap can cause the production of some products of incomplete combustion or recombination (such as PCDD/F) and dust. 

The emissive power of a fireball, however, will depend on the actual distribution of flame temperatures, partial pressure of combustion products, geometry of the combustion zone, and absorption of radiation in the fireball itself. The emissive power ( ) is therefore lower than the maximum emissive power (E ) of the black body radiation ... 

Although the gasifier product itself has low levels of NOx, the total systems emissions of this product must be carefully scrutinized. When clean biogas is eventually burned, NOx will be produced, as it is in most combustion systems with all fuels. The use of biogas rather than solid biomass fuels provides the opportunity to better control the combustion process, which can potentially result in lower NOx emissions. As such, gasification offers potential environmental emissions advantages over combustion alternatives. However, NOx may still occur as the gas is burned, and appropriate NOx control technologies may be needed. 

Whitby and Cantrell (16) report that aerosols collected near the surface of the earth are trimodal in nature. As listed in Table IV, these consist of distributions arising from (1) the irect emission of primary products from combustion having d = 0.02 un (2) coagulation of the aerosols from (1), or the c6ndensation of reaction products or water on the aerosols from (1), having = 0.16 and (3) larger particles arising from... 

Woodring JL, Duffy TL, Davis JT, et al. 1985. Measurements of combustion product emission factors of unvented kerosene heaters. An Ind Hyg Assoc J 46(7) 350-356. 

Reduction of Infrared Emission from Combustion Products 363... 

In the works devoted to study and development of MEISs numerous examples on their application to the analysis of various problems were certainly presented. They are formation of harmful substances during fuel combustion and cleaning of combustion products from these components, fuel processing, atmospheric pollution with anthropogenic emissions, stationary and nonstationary flow distribution in hydraulic systems, etc. These examples should illustrate practical efficiency of MEISs, their capabilities for revealing specific features of the modeled process and determining directions of its improvement. 

Combined Gas, Soot, and Particulate Emission In a mixture of emitting species, the emission of each constituent is attenuated on its way to the system boundary by absorption by all other constituents. The transmissivity of a mixture is the product of the transmissivities of its component parts. This statement is a corollary of Beer s law. For present purposes, the transmissivity of species k is defined as xk = 1 — Et. For a mixture of combustion products consisting of carbon dioxide, water vapor, soot, and oil coke or char particles, the total emissivity eT at any wavelength can therefore be obtained from... 

BOILERS—The control of combustion products varies with the fuel combusted and boiler design. For natural gas and fuel oil combustion, the control mechanism for NOx and CO emissions is typically a burner system that... 

The ubiquitous nature of PAHs in the environment, particularly as constituents of complex mixtures such as automobile emissions, coal tar, coke oven emissions, and combustion products of tobacco, increases the likelihood that the type of interactions discussed will occur. Thus, interactions may play a decisive role in the expression of toxicity and the development of cancer in exposed populations. 

---