Combustion-derived material

There are 210 different isomeric possibilities, 75 of which are PCDDs and 135 are PCDFs. The toxicity of these isomers varies greatly, and only 15 exhibit extreme toxicity, the most toxic of which is 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD). The toxicity of the other isomers is therefore expressed as a toxicity equivalent of 2,3,7,8-TCDD. The PCDDs and PCDFs are poorly water soluble but are fat soluble and are therefore able to accumulate in tissue fat, thus allowing them to bio-accumulate in living organisms. The origin of dioxins in the pulp and paper industry is not entirely clear. They may be produced from the chlorination of dibenzodioxin which may be present in recycled oils used to make defoamers, but they may also arise from wood chips which have been treated with polychlorophenol to prevent sap stain formation. It is also possible that they are derived from lignin by chlorination. Dioxins are also known to be formed naturally by combustion of material such as wood, and forest fires have been particularly identified as a likely major cause of dioxin emissions. 

Coal A sedimentary or metamorphic rock composed of at least 50 wt % and 70 v % combustible organic materials. In most cases, the organic carbon was derived from ancient terrestrial plants. Coals are potentially useful fuels (compare with lignite, subbituminous coal, bituminous coal, and anthracite). 

The combustible materials with which this paper is concerned are those used in building construction, such as wood and other compressed cellulosic derivative materials. The incombustible materials are metals which must be protected from reaching critical points when exposed to the heat of the fire. The critical points are the temperatures at which the metals soften and lose their structural strength under fire exposure. 

The oil furnace process uses aromatic petroleum oils and residues as feedstock and in the oil furnace process (Fig. 1), a highly aromatic feedstock oil (usually a refinery catalytic cracker residue or coal tar-derived material) is converted to the desired grade of carbon black by partial combustion and pyrolysis at 1400 to 1650°C in a refractory (mainly alumina) -lined steel reactor. 

Properties White powder or ointment-like granules or mass. Soluble in alcohol, ether, turpentine, and benzene insoluble in water. Combustible. Derivation Reaction of oleic acid with lead hydrate or carbonate, or of lead acetate and sodium oleate. Hazard Toxic material. Absorbed by skin. 

Additional support for the airborne transport of PAH is suggested by the results on the global distribution of PAH reported here. Thus, airborne transport of combustion-generated PAH from the New York City area to the sediments along the transect studied (Figure 5) is quite likely, especially since aeolian transport of land-derived material in this region has been documented (30). 

Barium hexaaluminate (BHA) has been prepared by a reverse microemulsion-mediated sol-gel method " . Several important preparation parameters were investigated in this work. Nanoparticles with excellent thermal stability could be obtained under optimal preparation conditions when compared to conventional sol-gel derived materials. This stability improvement is believed to occur since crystallization to the desired hexaaluminate phase took place at a relatively low temperature. Furthermore, this material has been tested as a catalyst for methane combustion . The light-olf temperature for 1 vol.% CH4 in air when using pure BHA as catalyst was observed to be 590 °C. This temperature could be lowered to 400 °C by depositing Ce02 on the catalyst. 

Energy derived from combustible waste materials or crops. 

In a more all encompassing classification, Doubleday (1999) produced a morphologically based description for all combustion derived particles collected in the eastern Canadian Arctic (including those from waste incineration, aircraft emission and domestic burning), where the fly-ash particles considered in this chapter formed classes, However, this was only used as a classification tool and not for fuel-type apportionment of the fly-ash particles. When applied to sediment material from the same area the results were expressed in terms of percentages of total particles or as percentages of total combustion particles. 

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