ENVIRONMENTAL ASPECTS OF COAL UTILIZATION in Visual C#.NET

Decoding ANSI/AIM Code 128 in Visual C#.NET ENVIRONMENTAL ASPECTS OF COAL UTILIZATION

During the combustion or conversion of coal, many compounds can be produced, some of which are carcinogenic Coal also contains nitrogen, oxygen, and sulfur as well as volatile constituents and the minerals that remain as ash when the coal is burned Thus some of the products of coal combustion can have detrimental effects on the environment For example, coal combustion produces carbon dioxide (CO2) and it has been postulated that the amount of carbon dioxide in the earth s atmosphere could increase to such an extent that changes in the earth s climate will occur Also, sulfur and nitrogen in the coal form oxides [sulfur dioxide (SO2), sulfur trioxide (SO3), nitric oxide (NO), and nitrogen dioxide (NO2)] during combustion that can contribute to the formation of acid rain

In addition, coal combustion produces particulate matter (fly ash) that can be transported by winds for many hundreds of kilometers and solids (bottom ash and slag) that must be disposed Trace elements originally present in the coal may escape as volatile material (eg, chlorine and mercury) or be concentrated in the ash (eg, arsenic and barium) Using such devices as electrostatic precipitators, baghouses, and scrubbers can trap some of these pollutants Alternate means for combustion (eg, fluidized bed combustion, magnetohydrodynamics, and low nitrogen dioxide burners) are also available to provide more efficient and environmentally attractive methods for converting coal to energy When carbon dioxide is released into the atmosphere it does not prevent the shorterwavelength rays from the sun from entering the atmosphere but does prevent much of the long-wave radiation reradiated from the earth s surface from escaping into the space The carbon dioxide absorbs this upward-propagating infrared radiation and reemits a portion of it downward, causing the lower atmosphere to remain warmer than it would otherwise be (the greenhouse effect) Other gases, such as methane and ozone also cause this effect and, consequently, are known as greenhouse gases

Clean coal technologies (CCTs) are a new generation of advanced coal utilization processes that are designed to enhance both the efficiency and the environment acceptability of coal extraction, preparation, and use These technologies reduce emissions waste and increase the amount of energy gained from coal The goal of the program was to foster development of the most promising CCTs such as improved methods of cleaning coal, fluidized bed combustion, integrated gasification combined cycle, furnace sorbent injection, and advanced flue-gas desulfurization Acid rain is the result of a series of complex reactions involving chemicals and compounds from many industrial, transportation, and natural sources Sulfur dioxide emissions from new coal-fired facilities have been controlled since the 1970s by the various government regulations The goal of the various regulations is to ensure the continued decrease in emissions of nitrogen and sulfur oxides from coal combustion into the atmosphere As a result, emissions of sulfur dioxide have dropped even though coal use has increased

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