Polychlorinated biphenyls combustion

M.3 Polychlorinated biphenyls (PCBs) were once widely used industrial chemicals but were found to pose a risk to health and the environment. PCBs contain only carbon, hydrogen, and chlorine. Aroclor 1254 is a PCB with molar mass 360.88 g-mol. Combustion of 1.52 g of Aroclor 1254 produced 2.224 g of CO, and combustion of 2.53 g produced 0.2530 g of H20. How many chlorine atoms does an Aroclor 1254 molecule contain ... 

Source Hexachlorobenzene may enter the environment from incomplete combustion of chlorinated compounds including mirex, kepone, chlorobenzenes, pentachlorophenol, PVC, polychlorinated biphenyls, and chlorinated solvents (Ahling et al., 1978 Dellinger et al., 1991). In addition, hexachlorobenzene may enter the environment as a reaction by-product in the production of carbon tetrachloride, dichloroethylene, hexachlorobutadiene, trichloroethylene, tetrachloro-ethylene, pentachloronitrobenzene, and vinyl chloride monomer (quoted, Verschueren, 1983). 

VAC TRAX is an ex situ thermal desorption process that separates contaminants such as volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), polychlorinated biphenyls (PCBs), and radioactive materials from soils, sludges, and solid trash. This process can be applied to mixed and unmixed waste streams. Because the nitrogen atmosphere in which the process occurs is inert, no combustion of organic material takes place. 

The electric infrared incineration technology is a mobile thermal processing system that is suitable for soils or sediments contaminated with organic compounds, polychlorinated biphenyls (PCBs), and metals. Liquid organic wastes can be treated after mixing with sand or soil. Electrically powered silicon carbide rods heat organic wastes to combustion temperature while any remaining combustibles are incinerated in an afterburner. 

Erickson MD, Swanson SE, Flora JD, et al. 1989. Polychlorinated dibenzofurans and other thermal combustion products from dielectric fluids containing polychlorinated biphenyls. Environ Sci Technol 23 462-470. 

Coincident with the development of sampling procedures were the constant iterative improvements in extraction, separation, identification and quantitation of organic compounds. Special emphasis was placed on selected compound classes such as the polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated benzenes, and chlorinated dibenzo-p-dioxins (dioxins). The best available procedures were used to determine these components because they have known acute or chronic effects and previous studies suggested that they might be present in effluents from the combustion of coal alone and combination coal/RDF. 

Polychlorinated Biphenyls (PCBs). The PCBs were observed in the stack effluents during the combustion of coal but these compounds were not produced in the combustion process by a de novo synthesis or from precursor compounds. The source of the PCBs was the indoor air used to support the combustion. This indoor air contained 0.11 ug/M3 of PCBs the concentration of PCBs in the stack gas was only 0.02 yg/M3 when coal containing no detectable level of PCBs was burned. For perspective, this emission level should be compared to the average ambient outdoor air level of about 0.006 yg/M3. 

Polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) (see Figure 1) are emitted into the atmosphere from the combustion of chlorine-containing materials.1-13 Additionally, PCBs, which were used as lubricants and dielectric fluids,13 are volatilized into the atmosphere from soils and bodies of water (for example, from the Great Lakes) after their disposal or inadvertent release into, and cycling through, the environment.114-18 Atmospheric concentrations of PCBs, PCDDs and PCDFs have been measured at numerous locations,2,15,1619-62 and these organochlorine... 

However, the use of perchlorates in pyrotechnic formulations is discouraged due to the supposed toxicity of this chemical which has been linked to causing thyroid disorders. Furthermore, the combustion of polychlorinated organic materials such as poly(vinyl) chloride has been shown to produce polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). These polychlorinated chemicals are highly toxic and are potent carcinogens. Therefore, the removal of perchlorates and chlorinated organic materials in pyrotechnic formulations would eliminate the formation of these aforementioned pollutants. 

Polychlorinated biphenyls (PCBs) are mixtures of biphenyls with 1 to 10 chlorine atoms per molecule. They are oily fluids with high boiling points, great chemical resistance, and low electrical conductivity, and have been used as plasticizers in polyvinyl polymers, insulators and coolants in transformers and heat exchange fluids. Dioxins and furans (see Section 9.1) are not produced intentionally but are derived from combustion processes of chlorinated aromatic hydrocarbons, pesticides and chlorinated solvents. 

Helm, P.A., Bidleman, T.F. (2003) Current combustion-related sources contribute to polychlorinated naphthalene and dioxin-like polychlorinated biphenyl levels and profiles in air in Toronto, Canada. Environmental Science and Technology, 37(6) 1075-1082. 

More recently, certain non-natural, exogenous contaminants in fats and vegetable oils have become an issue (43). Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dioxins, and aflatoxin, to name the more serious offenders, can hnd their way into fats and oils by a variety of pathways. In the case of PAHs, direct drying of seed materials (44, 45) is a major pathway. Dioxins, released to the environment as unintentional byproducts of combustion processes, are mainly found in animal and hsh fats as a result of ingestion of dioxin-contaminated feeds, soils, and sediments (46) by these animals. PCBs were used as dielectric fluids in electrical equipment and as flame-retardants until their production was banned (USA—1977 Europe—1985) they are generally not found in edible oils. 

See a/so Chlorophenols Combustion Toxicology Polychlorinated Biphenyls (PCBs) Polycyclic Aromatic Hydrocarbons (PAHs) TCDD (2,3,7,8-Tetrachlorodibenzo-p-Dioxin). 

Household wood combustion emissions Insecticides from spraying and application Polychlorinated biphenyls... 

Chlorobiphenyls (CBs) are used widely by industry, including transformers and capacitors in the electrical industry and inks, paints and paper in the printing and allied industries. Unwanted polychlorinated biphenyls (PCB) formulations and waste materials containing PCBs are normally incinerated. However, PCBs and waste products containing these materials are inadvertently or illegally disposed of at dump sites and landfill sites. Unsealed PCB sources are leached into the terrestrial and aquatic environment and incomplete combustion vaporises these compounds into the atmosphere therefore, they enter the wider global cycle of trace organic compounds and ubiquitous environmental contaminants that occur in bovine milk, milk powders and products as a result of intake via animal feed. 

In the latter area and in Waterways sediment three dominant and representative chemical groups were distinguished in the analyses and were selected for further study high molecular weight combustion polyaromatic hydrocarbons (CPAHs), polychlorinated biphenyls (PCBs) and lead. 

Table 6-5 Sediment Quality Criteria for Lead, Combustion Polyaromatic Hydrocarbons and Total Polychlorinated Biphenyls, as Derived from Data in Table 6-4 (after Chapman, 1986)...

More recently, environmental contamination by chlorinated dioxins and furans released during combustion processes has been recognized. These substances are formed not only during incineration of chlorinated phenols, but also during combustion of materials in home fireplaces and municipal incinerators (10). Chlorinated dioxins and dibenzofurans also are formed during fires involving polychlorinated biphenyls (15). 

Organic contaminants that present a concern to environmental protection include pesticides (used in agriculture), polycyclic aromatic hydrocarbons (PAHs, a by-product of incomplete combustion), polychlorinated biphenyls (PCBs, components of coolants and lubricants), phenols (used in the production of plastics and pesticides), dioxins (unwanted by-products of many industrial processes including incineration and chemical manufacturing of phenols, PCBs, and herbicides) and alkyphenols (surfactants in agrochemicals and household cleaning products). 

The polychlorinated biphenyls (PCBs) are synthetic organic chemicals with main sources in the environment being the processes of combustion and incineration (WHO, 1993). The organochlorine pesticides (OCPs), although banned internationally, can still be found in many environmental samples. Both classes of compounds are very persistent, tend to accumulate in the food chain and have negative effect on the human health (Cousins et al., 1998 Wade et al., 2002). For that reason many efforts have been made... 

HALOGENATED WAXES (1336-36-3) see PCBs or polychlorinated biphenyls. HALOWAX 1014 (1335-87-1) C,oH,CI Combustible solid (flash point unknown). Violent reaction with strong oxidizers, strong acids, powdered aluminum, potassium, sodium. On small fires, use dry chemical powder (such as Purple-K-Powder), alcohol-resistant foam, water spray, or COj extinguishers. Thermal decomposition releases toxic hydrogen chloride and phosgene gases. 

PHENOCHLOR (1336-36-3) see PCBs or polychlorinated biphenyls. PHENOL(108-95-2) CgHjOH Combustible solid, smelt (molten), or liquid [explosion limits in air (% by volume when heated) 3 to 10 flash point 174°F/79°C autoignition tenq) 1319°F/715°C Fire Rating 2]. Violent reaction with butadiene, strong oxidizers. Reacts, possibly violently, with strong acids caustics, aliphatic amines amides, oxidizers, calcium hypochlorite formaldehyde, lead diacetate menthol, y -naphthol, peroxydisulfuric acid peroxymonosulfuric acid potassiiun hydroxide sodium nitrite 1,2,3-trihydroxybenzene. Liquid attacks some... 

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