Chlorine emission

In 1990, a test using scrap tires (2x2 in. I DE) to generate steam for electricity was conducted at the Elexsys plant. The I DE replaced 20% of the plant s coal. Results showed that IDE is an environmentally sound fuel. Particulate emissions were reduced by the lower ash content of IDE, volatile organic compounds (VOC) were reduced because of more efficient burning of I DE compared to coal, and carbon dioxide emissions were reduced because I DE contains half the fixed carbon found in coal. Nitrogen oxide, chlorine emissions, and metals were also reduced, and ferrous metals and dioxins were nondetectable (7). 

Caustic scrubber systems should be installed to control chlorine emissions from condensers and at storage and transfer points for liquid chlorine. 

Rather than a tiered system to control hydrogen chloride and chlorine gas emissions, MACT combustion units must meet numerical emission limits for total chlorine. Owners and operators of these units must ensure that the total chlorine emission does not exceed specific limits, expressed in ppmv. For example, the allowable limit of total chlorine for a new incinerator is 21 ppmv. The owner or operator may choose to achieve this level by controlling the amount of chlorine entering the incinerator. By achieving the regulatory emission limit of chlorine, both hydrogen chloride and chlorine gas emissions will be reduced. 

Continuous measurement of NOx emissions in vent gases —Continuous emissions measurements of total hydrocarbons —Chlorine emissions monitoring —Hold-test-release protocols... 

Lobert JM, Keene WC, Logan JA, Yevich R (1999) Global Chlorine Emissions from Biomass Burning Reactive Chlorine Emissions Inventory. J Geophys Res 104 8373... 

McCulloch A, Aucott ML, Benkovitz CM, Graedel TE, Kleiman G, Midgley PM, Li YF (1999) Global Emissions of Hydrogen Chloride and Chloromethane from Coal Combustion, Incineration, and Industrial Activities Reactive Chlorine Emissions Inventory. 

Signorelli S. and Carroll M. R. (2001) Experimental constraints on the origin of chlorine emissions at the Soufriere HiUs Volcano. Montserrat. Bull. Volcanol. 62, 431—440. 

According to Lobert et al. (1999), the sum of aU chlorine emissions from biomass burning is —7Tg(Cl)a. About 9% is emitted as CH3CI, less than 1% as other alkyl chlorides while the largest part is emitted as unspecified volatile inorganic and as particulate chlorine. 

In an international effort, the Reactive Chlorine Emissions Inventory (Keene et al., 1999, and references therein) was compiled which includes chlorine emissions from the following four source-type classes (i) oceanic and terrestrial biogenic emissions (ii) sea salt aerosol production and dechlorination (iii) biomass burning and (iv) exclusively anthropogenic sources like industry, fossil fuel combustion, and incineration. They provide numbers from atmospheric burdens and fluxes for the individual species and sources. 

Aucott M. L., McCulloch A., Graedel T. E., Midgley P., and Li Y.-F. (1999) Anthropogenic emissions of trichlorometh-ane (chloroform, CHCI3 and chlorodifluoromethane (HCFC-22) reactive chlorine emissions inventory. J. Geophys. Res. 104, 8405-8415. 

Chang S., McDonald-Buller E., Kimura Y., Yarwood G., Neece J., Russell M., Tanaka P., and Allen D. (2002) Sensitivity of urban ozone formation to chlorine emission estimates. Atmos. Environ. 36, 4991-5003. 

Emission of hydrogen chloride is the third most important contribution to the global acidification from human activities. The two first are SO2 and NO, The HCI is a local pollutant, contrary to the other two. It is soluble in water and easily dissolved in rain droplets and, therefore, usually falls down near the emission source. The hydrogen chlorine emissions from combustion and gasification processes has been calculated to 3,5 Mt./year, The major part of the estimated global contribution of HCI to the atmosphere is evaporation from the oceans. Even with a redeponation of 90-% HCI to the oceans, the estimated emission will reach approximately 120 Mt./year, The majority of the emitted chlorine from a combustion process will leave as HCI in the gas phase which may cause problems like corrosion and formation of dioxins. 

Woody biomass is low in ash content, sulphur, chlorine and silica, and the ash itself is dominated by compounds of Ca and K. Biomass fuels from crops are higher in ash content, sulphur, chlorine and silica. The ash is dominated by oxides of Ca, K and Si. The fuels based on the growing parts of trees (bark+debries) show ash compositions between the two extremes, wood and acre crops. Therefore the largest chlorine emissions are expected from energy crops (grasses) and from agricultural by products (straw etc). 

Erickson, D. I, III, C. Seuzaret, W. C. Keene and S. L. Gong (1999) A general circulation model based calculation of HCl and CINO2 production from sea salt dechlorination Reactive chlorine emissions inventory. Journal of Geophysical Research 104, 8347-8372 Erickson, D. J., Ill (1993) A stability dependent theory for air-sea gas exchange. Journal of... 

Graedel T. E. and W. C. Keene (1999) Overview Reactive chlorine emissions inventory. Journal of Geophysical Research 104, 8331-8333... 

McCulloch, A., M. L. Aucott, C. M. Benkovitz, T. E. Graedel, G. Kleiman, P. M. Midgley and Y.-F. Li (1999) Global emissions of hydrogen chloride and chloromethane from coal combustion, incineration, and industrial activities Reactive chlorine emissions inventory. Journal of Geophysical Research 104, 8391-8404... 

Self, S. and A. X King (1996) Petrology and sulfur and chlorine emissions of the 1963 eruption of Gunung Agung, Bali, Indonesia. Bulletin Volcanology 58, 263-285 Self, S. (2006) The effects and consequences of very large explosive volcanic eruptions. Philosophical Transactions of the Royal Society A 364, 2073-2097 Sephton, M. A. (2002) Organic compounds in carbonaceous meteorites. Natural Products Reports 19, 292-311... 

Significant inputs of chlorine gas are emitted into the atmosphere in New York State the major source of chlorine emissions occurs in Niagara County, New York. Oxidant residuals have been measured in rainfall from Central New York. Maximum residuals in rainfall coincided with depressed pH values and maximum rainwater... 

Chlorine emissions in tons per year are summarized by county in Figure 1 these estimates may be conservative but do reflect potential source emissions. As suspected, the major source of chlorine emissions occurs in Niagara County, emitting approximately 185 tons per year Hooker Chemical Company of Niagara Falls, alone, emits 125 tons per year and is considered the largest chlorine emitter in the State. Other major centers of emissions include portions of Central and New York. These findings indicate that sig-quantities of chlorine gas are emitted into the atmosphere within New York State the possible transport and washout in rainfall of these emissions warrants further attention. 

Figure 1. Chlorine emissions for each county within New York State.

The final vent from the system should be regarded as a point of possible chlorine emission. It should be at a high level and away from personnel traffic and ventilation system intakes. Particularly when the low-pressure scrubbing device is a packed bed, booster fans may be added on the tail pipe. The piping arrangement around the fans then should avoid low points that could collect liquid. As with any vent manifold, the designer of a system serving several different units should take precautions to avoid mixtures in headers that may lead to undesirable side reactions. 

Khalil MAK, Moore RM, Harper DB, Lobert JM, Erickson DJ, Koropalov V, Sturges WT, Keene WC (1999) Natural emissions of chlorine-containing gases reactive chlorine emissions inventory. J Geophys Res Atmos 104 8333... 

In urban areas, chlorine emission originates mainly from the untreated smoke of household waste incineration plants burning plastic packaging, especially PVC-containing waste. In the atmosphere, chlorine in contact with moisture is transformed into hydrochloric acid. 

Chlorine emissions accelerate the atmospheric corrosion of all common metals, including aluminium. The higher the chlorine concentration and especially the higher the level of relative humidity the more this will be accelerated. This has been shown by test results at high chlorine levels (which are out of proportion with those found in an atmosphere polluted by chlorine emissions) (Table C.2.6). 

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