Polyvinyl chloride combustion

Polyvinyl chloride is considered to be a self-extinguishing polymer - in other words, it does not support combustion well. Why does it exhibit this behavior ... 

Ahling B.. Bjorseth, A., and Lunde, G. Formation of chlorinated hydrocarbons during combustion of polyvinyl chloride. Chemosphere, 7(10) 799-806, 1978. 

Combustible binder Polybuta- diene Cellulose acetate Polyurethane Polyurethane Polyester Polyvinyl chloride... 

The combustion of polyacrylonitrile produces hydrogen cyanide. Any of the chlorine-containing polymers will produce hydrogen chloride upon combustion. This would include polyvinyl chloride and polyvinylidene chloride. 

Coal Mine Fires. Fires in coal mines are particularly dangerous not only because a naked flame may ignite firedamp (or coal dust) and initiate an expln, but also because coal itself provides a virtually unexhaustible supply of fuel. Every precaution should be taken to prevent such fires and the use of combustible materials in mines should be avoided. As an example of fire caused by a combustible article, may be cited the disastrous fire in 1950 at Creswell Mine, England, responsible for the death of 80 people. It was caused by flammable rubber conveyer belting. To prevent a repetition of such disaster, the British National Coal Board ordered replacement of all underground rubber belting by non-flammable polyvinyl chloride belting... 

Polyvinyl chloride (PVC) is a common plastic that can produce dioxins and furans when burned. PVC is often present in municipal waste in large amounts, and is believed to contribute to the dioxins and furans from incinerators. Many sources of combustion produce dioxins and furans. Incinerators, both municipal and industrial, are significant sources dioxins and furans have been found in incinerator ash and in gases and tiny particles escaping through smokestacks. Power plants, smelters, steel mills, oil and wood stoves, and furnaces all emit dioxins and furans. 

Dioxins and furans are not produced deliberately, but are produced unintentionally as byproducts of combustions of organic matter in the presence of chlorine. Dioxins and fiirans consists of 135 possible chlorinated dibenzoftnan and 75 chlorinated dibenzo-p-dioxins with Irom 1 to 8 chlorine substituents (Figure 18.2). PCDDs/DFs are found as byproducts during the manufacture of some industrial chemicals such as PCBs, polychlorinated naphthalenes, chlorinated phenols, chlorinated phenoxyacids, polychlorinated diphenyl ethers, polyvinyl chlorides, and chlorinated phenoxy-2-phenols (Hutzinger et al, 1985 Hryhorczuk et al, 1986 ATSDR, 2001 Masunaga et al. 

Solubility in organic solvents Tetrahydrofuran (THF is regarded as a solvent with very universal properties, however it is combustible and its vapors must not be inhaled (see Section 7.5.2). In addition, suitable solvents are acetone and methyl-ethyl ketone. Thermoset materials are generally insoluble, polyvinyl chloride, Plexiglas, polystyrol, rubbers and poorly crosslinked polyurethane are swellable thermoplastics. 

Among various natural sources, the largest amounts of chlorinated hydrocarbons are supplied into the air by forest fires. In the combustion of cellulose, 2.2 mg of methyl chloride are formed per 1 g of substance burnt. Anthropogenic sources include the combustion of PVC (polyvinyl chloride) wastes, burning of plants in agriculture and uncontrolled fires resulting from human activity. 

The presence of chlorinated organic matter in a fuel will result in the formation of objectionable substances like HCl, halogenated acids, and other organochlorine compounds in the incinerator exit gases and particles (Eiceman et al., 1979 Mowrer and Nordin, 1987). During the combustion of chlorine-containing organic materials such as polyvinyl chloride and polyvinylidene chloride (36 and 37, respectively), new... 

Experimental and theoretical studies are presented from a laboratory-scale thermal destruction facility on the destructive behavior of surrogate plastic and nonplastic solid wastes. The nonplastic waste was cellulosic while the plastic waste contained compounds such as polyethylene, polyvinyl chloride, polystyrene, polypropylene, nylon, rubber, and polyurethane or any of their desired mixtures. A series of combustion tests was performed with samples containing varying composition of plastic and nonplastic. Experimental results are presented on combustion parameters (CO, excess air, residence time) and toxic emissions (dioxin, furan, metals). 

Computational Results Equilibrium thermochemical calculations (using STANJAN [35] and SOLGASMIX [36] codes) of a mixture of nonplastic and plastic surrogate solids were carried out under conditions of pyrolysis and combustion see Table 15.9. A large thermodynamic data file compiled from JANAF tables is used in these codes [37]. The nonplastic material is assumed to be cellulose while the plastic material may contain any or all of the following plastics polyethylene, polyvinyl chloride, polystyrene, polypropylene, polyethylene ter-aphathalic, nylon, latex in the form of rubber, polyurethane, and acetate. Cellulose represents the organic portion of the waste such as paper and cardboard. 

Other materials such as alumina trihydrate and magnesium hydroxide can be added to polyethylene to provide some measure of fire resistance. The resultant materials are termed flame-retardant polyethylenes (FRPE). FREE jacket materials are used in place of standard fire-resistant cable jackets when there are concerns that other compounds would release excessive combustion byproducts that are life-threatening, or which could damage sensitive electronics, if burned. Such materials do not have the same level of fire-resistance as the polyvinyl chloride (FVC) and polyvinylidene fluoride (FVDF) materials commonly used for indoor cable, so there are tradeoffs to consider when looking at the need for fire-resistance. Note that since jacket tracking is effectively caused by localized heating of the jacket material, some TRPEs and FRPEs may have similar material characteristics. 

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