Understanding coal fired_thermal_power_plants


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  • In a thermal power plant, steam is produced and used to spin a turbine that operates a generator. Shown here is a diagram of a conventional thermal power plant, which uses coal, oil, or natural gas as fuel to boil water to produce the steam. The electricity generated at the plant is sent to consumers through high-voltage power lines.
  • Source:www.nwf.org
  • Understanding coal fired_thermal_power_plants

    1. 1. <ul><li>Power generating units are mega projects </li></ul><ul><li>Require huge capital investment </li></ul><ul><li>Require natural resources like, fossil fuels </li></ul><ul><li>Large amount of water </li></ul><ul><li>Changes the local eco system </li></ul><ul><li>Huge Impacts on the Environment and Health </li></ul>
    2. 3. <ul><li>In keeping with the policy of liberalization set in motion since 1991, welcoming private sector participation, Thermal Projects identified for private sector Participation in Karnataka </li></ul><ul><li>Mysore Stage I 2x250 MW </li></ul><ul><li>Mysore Stage II 2x500 MW </li></ul><ul><li>Hospet Thermal Power Station 2x250 MW* </li></ul><ul><li>Raichur Thermal Power Station 2x250 MW * </li></ul><ul><li>Mangalore Thermal Power Station 1000 MW </li></ul>
    3. 9. <ul><li>Air Quality </li></ul><ul><li>Around the coal based plants the ambient concentrations of Sulphur Dioxide, Oxides of Nitrogen and SPM are high. </li></ul><ul><li>Epidemiological Studies have shown that of the area surrounding coal based thermal plants, population living within a 2 -5 km radius of the plant suffers from respiratory disorders . </li></ul><ul><li>Two other gases, carbon dioxide and ozone are emitted. The high amount of carbon dioxide emission from thermal power plants contribute to global warming leading to climate change is significant Ground level ozone, which is formed due to photolytic reactions of NO x and its impacts are under study </li></ul>
    4. 10. <ul><li>Fly ash contains a toxic brew of dangerous chemicals and is the largest contributor to mercury pollution </li></ul>
    5. 11. <ul><li>Composition of Fly ash </li></ul><ul><li>It contains as main chemical components SiO2 (51.4 wt%), Al2O3 (22.1 wt%) and Fe2O3 (17.2 wt%; ignited weight basis). As commonly observed, many toxic elements and heavy metals are highly enriched in the fly ash relative to the original coal. For example, considerable amounts of Be (16.4 ppm), Cu (106 ppm), Zn (578 ppm), As (40.4 ppm), Cd (2.6 ppm), Hg (18 ppm), Pb (71 ppm), and U (21.8 ppm) is found in Fly ash. </li></ul>
    6. 12. <ul><li>Water slurry is used to take the ash from the power plant to the ash pond for disposal.  </li></ul><ul><li>Water slowly seeps into the ground while carrying with it the ash leachate. Water may contain harmful heavy metals like boron, which have a tendency to leach out over a period of time.  </li></ul><ul><li>When fly ash comes into contact with water, leaches into groundwater supplies which get polluted and unsuitable for domestic use.  </li></ul><ul><li>The release of ash pond decant into the local water bodies- water dries up, dust nuisance, increases turbidity, decreases primary productivity, affects fishes and other aquatic biota </li></ul>
    7. 13. <ul><li>The exposure of employees to high noise levels is very high </li></ul><ul><li>Increased transportation activities due to the operation of the power plants lead to increase in noise levels in the adjacent localities. </li></ul>
    8. 14. <ul><li>Large amount of land is used to dispose flyash from the coal based plants </li></ul><ul><li>Due to this there is change in natural soil properties.  It becomes more alkaline due to the alkaline nature of fly ash. </li></ul>
    9. 15. <ul><li>Minamata disease sometimes referred to as Chisso-Minamata disease is a neurological syndrome caused by severe mercury poisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of vision and damage to hearing and speech. In extreme cases, insanity, paralysis, coma and death follow within weeks of the onset of symptoms. A congenital form of the disease can also affect fetuses in the womb. </li></ul>
    10. 16. <ul><li>Minamata disease was first discovered in Minamata city in Japan in 1956. It was caused by the release of methyl mercury in the industrial Waste water from the Chisso Corporation's chemical factory, which continued from 1932 to 1968. This highly toxic chemical bioaccumulated in shellfish and fish in Minamata Bay and the Shiranui Sea, which when eaten by the local populace resulted in mercury poisoning. While cat, dog, pig and human deaths continued over more than 30 years, the government and company did little to prevent the pollution. </li></ul>
    11. 17. <ul><li>As of March 2001, 2,265 victims had been officially recognised (1,784 of whom had died)and over 10,000 had received financial compensation from Chisso, lawsuits and claims for compensation continue to this day. </li></ul><ul><li>A memorial service was held at the Minamata Disease Municipal Museum on 1 May 2006 to mark 50 years since the official discovery of the disease. </li></ul>
    12. 19. <ul><li>Each year power plants and chemical facilities create many tons of mercury pollution, which makes its way into our homes and bodies in fish. </li></ul><ul><li>Two of the biggest sources of mercury pollution are chlorine chemical plants and coal-fired power plants. Chlorine plants, which use massive quantities of mercury to extract chlorine from salt, &quot;lose&quot; dozens of tons of mercury each year; power plants emit around 50 tons of mercury pollution annually. Coal is naturally contaminated with mercury, and when it is burned to generate electricity, mercury is released into the air through the smokestacks. </li></ul>
    13. 21. <ul><li>Coal-fired power plants are the largest source of mercury air emissions worldwide. As the price of oil rises, coal becomes a more economically attractive source of energy in countries where it is abundant and inexpensive. Currently, coal-fired power plants supply seventy-five percent of China's energy; in the next eight years, China is expected to add more than 560 plants coal plants -- a pace of more than one new plant each week. </li></ul>
    14. 23. Land acquisition leads to loss of habitat of some species and results in loss of flora and faunal species
    15. 24. <ul><li>Uses of Fly ash </li></ul><ul><li>Fly ash is used in producing very strong high power concrete. Which is called self compacting Concrete(SCC), soil stabilization, fly ash fills roads, precast products like tiles and blocks, fly ash bricks also called green bricks , agricultural use , raising of dykes, mine filling etc. </li></ul>
    16. 25. <ul><li>Toxicology: </li></ul><ul><li>How Mercury Harms Humans Elemental (metallic) mercury and all of its compounds are toxic, exposure to excessive levels can permanently damage or fatally injure the brain and kidneys. </li></ul><ul><li>Elemental mercury can also be absorbed through the skin and cause allergic reactions. Ingestion of inorganic mercury compounds can cause severe renal and gastrointestinal damage. </li></ul><ul><li>Organic compounds of mercury such as methyl mercury are considered the most toxic forms of the element. Exposures to very small amounts of these compounds can result in devastating neurological damage and death. </li></ul><ul><li>For fetuses, infants and children, the primary health effects of mercury are on neurological development. </li></ul><ul><li>Even low levels of mercury exposure such as result from mother's consumption methyl mercury in dietary sources can adversely affect the brain and nervous system. </li></ul><ul><li>Impacts on memory, attention, language and other skills have been found in children exposed to moderate levels in the womb. </li></ul>
    17. 28. <ul><li>Air borne mercury is highly toxic when inhaled. How does it get in the air? Metallic mercury slowly evaporates when exposed to the air. The air in a room can reach unhealthy levels just from the mercury in a broken thermometer; </li></ul><ul><li>Mercury may be released into the air when coal, oil, or wood are burned as fuel or when mercury-containing wastes are incinerated. The resulting mercury concentrations in outdoor air are usually low and of little direct concern. However, mercury in the air can fall to the ground with rain and snow, landing on soil or in bodies of water, causing contamination. Lakes and rivers are also contaminated when there is a direct discharge of mercury-laden industrial or municipal waste into the water. </li></ul><ul><li>When mercury enters bodies of water, biological processes transform it to methylmercury, a highly toxic and bioaccumulative form. Fish can absorb methylmercury from their food and directly from water as it passes over their gills. </li></ul>
    18. 29. <ul><li>The cycle of mercury in nature is complex. This illustration summarizes how methyl mercury accumulates at the higher levels of the food chain and becomes concentrated in fish and animals that eat fish. </li></ul><ul><li>Methylmercury in the water and sediment is taken up by tiny animals and plants known as plankton. </li></ul><ul><li>Minnows and juvenile fish eat large quantities of plankton over time. </li></ul><ul><li>Larger predatory fish consume many smaller fish, accumulating methylmercury in their tissues. The older and larger the fish, the greater the potential for high mercury levels in their bodies. </li></ul><ul><li>Fish are caught and eaten by humans and animals, causing methylmercury to accumulate in human tissues. </li></ul><ul><li>Most people are exposed to mercury by eating fish containing mercury. There is no method of cooking or cleaning them that will reduce the amount of mercury in a meal. </li></ul>
    19. 32. <ul><li>Bio fuel </li></ul>