Domestic coal combustion

With regard to arsenosis related to domestic coal combustion, at least 3000 patients have been diagnosed in southwest Guizhou Province, with Xingren... 

During the investigation of chronic arsenic poisoning in southwestern Guizhou Province, Dr. D. Zhou developed an effective field test to analyze the As content of coal samples from small mines used by the villages for domestic coal combustion... 

Harrad SJ, Fernandes AR, Creaser CS (1991), Chemosphere 23 255-261.. .Domestic coal combustion as a source of PCDDs and PCDFs in the British environment"... 

However, 2,3-benzofuran was detected in emissions from a Swedish floor finish used on domestic flooring (van Netten et al. 1988), and in emissions from the pyrolysis of silk (Junk and Ford 1980), and in combustor flue gas emissions from fluidized-bed coal combustion at a concentration of 900 ng/g (Hunt et al. 1982). Exhaust produced by an automobile burning simple hydrocarbon fuels contained 2,3-benzofuran at concentrations ranging from less than 0.1 to 2.8 ppm (Seizinger and Dimitriades 1972), but an analysis of air in a highway tunnel in use by both diesel- and gasoline-powered vehicles indicated no... 

Coal combustion provides a substantial fraction of world energy production, both thermal and electrical. In addition, coal and its semi-processed derivative, coke, are cheap chemical reductants essential to the extraction of a variety of metals from their ores (e.g., Fe, Mn, Cu). The market for coal is likely to increase over the next decade only slowly in developed countries but more rapidly in developing countries with suitable domestic resources (e.g., China, India). 

MHD Coal/oil mixture (COM) Industrial heat/steam Pulverized Fluidized-bed Stoker COM Domestic/commercial Combustion energy capture by magnetic fields Burning coal/oil mixtures in oil furnaces Industrial plant power Hand-stoked space heating 8-11 1 Laboratory Demonstration Small Pilot Common Demonstration 800-4000 1-100 1-100 1-100 1-100 0.005-0.05 Same as above Noncaking 3-10 cm... 

These ratios indicate that there is a need for a very different secondary air supply in the combustion of urban waste compared with coal. In addition, because the deposits associated with domestic refuse combustion are generally alkali metal salts of relatively low melting point, it may be necessary to consider diluting the gases leaving the combustion space to reduce their temperature to below 650°C, the sintering temperature of the salts. The dilution may be achieved by the use of tertiary mr but this will, of course, reduce the thermal efficiency of the equipment. 

All the temperatures for the coal ash are significantly higher than the corresponding temperatures for the refuse derived fuel. The reason for these differences is that the ash produced by the combustion of domestic refuse, is different in chemical composition from the ash associated with coal combustion. 

Coal combustion is used in a range of applications, which vary from domestic fires to large industrial furnaces and utility boilers. While, for reasons of economy, the oxidant is usually air. 

The best-known example of coal combustion is provided by the domestic fire and the majority of industrial coal burners operate on the same overfeed principle. Once combustion has commenced, a number of separate reaction zones can be distinguished (Figure 14.12). The fresh, or green, coal is placed on the upper surface and the heat transferred from the bed below causes evaporation of the volatile material that burns in the secondary air and leaves a residue of fixed carbon or coke. 

Coal Combustion and Electricity Production World coal consumption is about 3.3 billion tonnes oil equivalent annually (2008), of which about 75% is used for to generate electricity. Coal currently supplies about 39% of the world s electricity, 4% based on lignite and 35% based on black (hard) coal (RWE, 2005). For electricity generation, coal is usually pulverized and burned in a furnace with a boiler to produce steam that is used in turbines to create electricity with about 40% efficiency for the entire process. In addition to electricity production, 13% of the global coal production is burned in the domestic and non-metallic industry, for example, for cement production. 

Moreover recent proposed amendments to the US Clean Air Act of 1970 have led to a number of possible compliance scenarios for the US utilities industry. As the title of this chapter suggests, the benefidal impact upon the environment has largely been lost in the arguments over the economic impacts. Similar debates are likely to arise in the UK in response to the European Commission s Large Plant Combustion Directive which will involve comparable discussions over waste disposal, the impact on the domestic coal industry and the choice of emission control technologies. 

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