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Ultra-mega thermal plants Trends Prof Yash
Pal THIS UNIVERSE |
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Ultra-mega thermal plants A recent report datelined Bathinda, filed by TNS correspondent S.P. Sharma appeared in The Tribune dated October 31 describing the situation at Bathinda City: “It flyash all the way in Bathinda” along with a photograph of a scooterist virtually sailing through a cloud of flyash. This has made many of us ponder what would be the state of affairs once the two proposed “ultra-mega thermal plants” of Talwandi Sabo and Gidderbaha start operating.
An attempt has been made in this article to consider the problem. At the present stage, the thermal plants installed in Punjab have the capacity of 2120 MW, with 1260 MW Super Plant at Ropar, 440 MW Plant at Bathinda and 420 MW at Lehra Mohabat. The annual production of solid waste in the form of flyash (containing 20 per cent furnace bottom ash) from all the above listed TPs is around 20 lakh tons. The new thermal plants planned would add an additional generation capacity of 6480MW: l 1980 MW from the Talwandi Sabo Ultra-Mega Thermal Plant. l 2640 MW from the Gidderbaha Ultra-Mega Thermal Plant, l 1320 MW from the Rajpura Mega Thermal Plant l 540 MW from the Goindwal Thermal Plant. At that stage, the total thermal power generation capacity would be 8600 MW and the annual flyash production requiring proper handling would be above 80 lakh tonnes. The regulations issued by the Ministry of Environment and Forest (MOEF), Government of India, require that “all the thermal plants will have to ensure 100 per cent utilisation of the solid waste (flyash plus furnace bottom ash) within the prescribed period, which is nine years after their commissioning in the case of new TPs to be set up. In the case of the older existing plants, the time limit to achieve the 100 per cent utilisation target is “by the year 2015” i.e. within the next seven years. Flyash is fine powdery material and its particles are spherical in shape and of glassy nature. The flyash contains a reactive material which reacts with “lime” in the presence of water, to form calcium silicate hydrate, which acts as a binding material. This property of flyash is utilised for part replacement of cement in the case of cement concrete using OPC (Ordinary Portland Cement). Also PPC (Portland Puzzolana Cement) is obtained by mixing flyash with burnt clinker before grinding. The proportion of flyash, conforming to IS: 3812 (Part I-1) may vary between 15 per cent to 35 per cent. l Flyash can be used to form a “flowable fill” which pours freely and get set quickly and provide strength equal to that of “compacted soil”. So flyash in this form can be used to fill up trenches, cuts, abandoned mine etc. l Flyash can be used for building embankments for road construction. l Flyash can be used as “filler” in the manufacture of plastic components replacing “plastic resin”. Roller compacted concrete using flyash has been found to possess many merits and used in many situations. In case of the Ghatgar pumped storage scheme, the roller compacted concrete using flyash was used for construction of the Saddle Dam and the Upper Dam. Flyash has been beneficially used for “soil conditioning” of agricultural soils in Maharashtra and flyash has also been used to provide “fertiliser capability”. For this purpose it should be used in the “wet” form For burnt clay bricks, a 25 per cent replacement of soil with flyash is now a must for brickkilns located within 100 km. radius of TPs as per orders from the MOEF. Building blocks using upto 88 per cent of flyash: furnace bottom ash (in equal proportion) and 12 per cent lime have been produced by PMET, who has obtained a patent for the same. The blocks are “cured” in an auto-clave for six hours at steam pressure of 200 psi and 370 degree F temperature. The product thus obtained is called “BRIXX”. In case of the Ropar super thermal plant, the ash ponds were found to pollute groundwater and objections were raised the Punjab Pollution control Board and the PSEB was asked to take necessary steps’ to check this menace. Also, the air pollution has been found to be acute around the Ropar thermal plant area and so it has been decided to raise the chimney height by 200 ft to correct the situation by dispersing the pollutants over a wider area so as to minimise their intensity. Farmers in the areas surrounding the Ropar TP have complained of reduction in crop yields on account of ground water as well as atmospheric pollutants. This aspect needs to be studied by agencies like the PAU. This scenario is true for all thermal plants, though the intensity of the problem could vary. For the new Ultra-Mega Thermal Plants coming up, one can only hope that all the necessary environmental clearances are obtained and implemented in letter and spirit to avoid an environmental catastrophe. While Punjab enters the “Ultra-Mega Thermal” era to tackle its rising power needs, we should also plan ahead for disposal and utilisation of the mega-quantities of the solid wastes that would be obtained (flyash & FBA), so that environmental degradation is not obtained in the area of influence around these Ultra-Mega Thermal Plants. Progress and growth at the cost of the environment is not an acceptable trade-off. Keeping in mind that the binding 100 per cent flyash usage regulations are still 7-9 years away from implementation, we hope that we can avoid the Bathinda scooterist’s plight being repeated in other cities and villages of Punjab — the green state. |
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Trends More than 400 years after Danish astronomer Tycho Brahe challenged established wisdom about the heavens by analyzing a strange new light in the sky, scientists say they’ve finally nailed down just what he saw. It’s no big surprise. Scientists have known the light came from a supernova, a huge star explosion. But what kind of supernova? A new study confirms that, as expected, it was the common kind that involves the thermonuclear explosion of a white dwarf star with a nearby companion. The research, which analyzed a “light echo” from the long-ago event, is presented in Thursday’s issue of the journal Nature by scientists in Germany, Japan and the Netherlands. The story of what’s commonly called Tycho’s supernova began on Nov. 11, 1572, when Brahe was astonished to see what he thought was a brilliant new star in the constellation Cassiopeia. The light eventually became as bright as Venus and could be seen for two weeks in broad daylight. After 16 months, it disappeared. — AP
Fabric wipes away toxic chemicals A new dry wipe can clean up chemical agents such as mustard gas, giving soldiers a more convenient way to deal with toxic materials on the battlefield, U.S. researchers said on Wednesday. The wipe was developed by researchers at Texas Tech University in Lubbock in response to a call by the U.S. military for better ways to decontaminate military personnel and equipment. “This is the first time this kind of wipe has been developed and it has been tested against a real chemical agent,” Seshadri Ramkumar of Texas Tech, who developed the wipe, said in a telephone interview. — Reuters
Brains getting rewired? What does a teenage brain on Google look like? Do all those hours spent online rewire the circuitry? Could these kids even relate better to emoticons than to real people? These sound like concerns from worried parents. But they’re coming from brain scientists. While violent video games have gotten a lot of public attention, some current concerns go well beyond that. Some scientists think the wired world may be changing the way we read, learn and interact with each other. There are no firm answers yet. But Dr. Gary Small, a psychiatrist at UCLA, argues that daily exposure to digital technologies such as the Internet and smart phones can alter how the brain works. —AP
Perfume vials from Christ era A team of Franciscan archaeologists digging in the biblical town of Magdala in what is now Israel say they have unearthed vials of perfume similar to those that may have been used by the woman said to have washed Jesus’ feet. The perfumed ointments were found intact at the bottom of a mud-filled swimming pool, alongside hair and make-up objects, the director of the dig conducted by the group Studium Biblicum Franciscanum told the Terrasanta.net religious website. —Reuters |
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THIS UNIVERSE Air particles have certain weight. Why do not they fall on the earth due to its gravity? Why do they float in the space above the earth? The atmosphere is not at a temperature of 0 degrees Kelvin. If it were then all particles of atmosphere would condense on the surface of the earth. But the temperature of the atmosphere gives them certain random velocities. At any level in the atmosphere the pressure created by the random velocities of particles exactly balances the weight of the air mass above. That is the reason they do not fall on the earth. A body in still water moving with a constant speed produces waves. Then why does not the information of a charged particle moving with a constant speed spread in the space? Why is it necessary for it to be accelerated or decelerated? The moving body in still water makes waves because it is disturbing that water, even if it seems to remain still. Even though mechanical analogies are not very instructive for electromagnetic phenomena, a mechanical object moving in empty space away from all other objects remains undisturbed in its travel. As an approximate example think of the motion of the earth around the sun. It keeps going. If a charged body moves at constant speed, it implies that it is not losing any energy. If so it cannot be sending any signal of its presence because that also costs energy. Is it possible to increase the temperature of a gas by decreasing the number of molecules provided that pressure and volume are kept constant. I suggest you fix a picture in your mind. If you have a fixed volume with some gas in it, there would be a pressure on the walls of the vessel. This pressure will depend on the momentum of individual molecules bouncing off the walls and the number of molecules, per second that do the bouncing. The momentum of molecules depends on their random energy, which depends on temperature. If the number of molecules is decreased while keeping the volume constant, the only way to keep the pressure constant is to increase the energy of the molecules — which is the same thing as increasing the temperature. So your statement should be: If the number of molecules is decreased, the only way of keeping the pressure and volume constant is to increase the temperature! |
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