Thermal power plant working indian power sector electricity towers health risks


At present 54.09% or 93918.38 MW (Data Source CEA, as on 31/03/2011) of total electricity production in India is from Coal Based Thermal Power Station. A coal based thermal power plant converts the chemical energy of the coal into electrical energy. This is achieved by raising the steam in the boilers, expanding it through the turbine and coupling the turbines to the generators which converts mechanical energy into electrical energy.

In a coal based power plant coal is transported from coal mines to the power plant by railway in wagons or in a merry-go-round system. Coal is unloaded from the wagons to a moving underground conveyor belt. This coal from the mines is of no uniform size. So it is taken to the Crusher house and crushed to a size of 20mm. From the crusher house the coal is either stored in dead storage( generally 40 days coal supply) which serves as coal supply in case of coal supply bottleneck or to the live storage(8 hours coal supply) in the raw coal bunker in the boiler house. Raw coal from the raw coal bunker is supplied to the Coal Mills by a Raw Coal Feeder. The Coal Mills or pulverizer pulverizes the coal to 200 mesh size. The powdered coal from the coal mills is carried to the boiler in coal pipes by high pressure hot air. The pulverized coal air mixture is burnt in the boiler in the combustion zone electricity kwh to unit converter.

Generally in modern boilers tangential firing system is used i.e. the coal nozzles/ guns form tangent to a circle. The temperature in fire ball is of the order of 1300 deg.C. The boiler is a water tube boiler hanging from the top. Water is converted to steam in the boiler and steam is separated from water in the boiler Drum. The saturated steam from the boiler drum is taken to the Low Temperature Superheater, Platen Superheater and Final Superheater respectively for superheating. The superheated steam from the final superheater is taken to the High Pressure Steam Turbine (HPT). In the HPT the steam pressure is utilized to rotate the turbine and the resultant electricity history united states is rotational energy. From the HPT the out coming steam is taken to the Reheater in the boiler to increase its temperature as the steam becomes wet at the HPT outlet. After reheating this steam is taken to the Intermediate Pressure Turbine (IPT) and then to the Low Pressure Turbine (LPT). The outlet of the LPT is sent to the condenser for condensing back to water by a cooling water system. This condensed water is collected in the Hotwell and is again sent to the boiler in a closed cycle. The rotational energy imparted to the turbine by high pressure steam is converted to electrical energy in the Generator.

The turbine generator consists of a series of steam turbines interconnected to each other and a generator on a common shaft. There is a high pressure turbine at one end, followed by an intermediate pressure turbine, two low pressure turbines, and the generator. The steam at high temperature (536 ‘c to 540 ‘c) and pressure (140 to 170 kg/cm2) is expanded in the turbine.

The cooling tower is a semi-enclosed device for evaporative cooling of water by contact with air. The hot water coming out from the condenser is fed to the tower on the top and allowed to tickle in form of thin sheets or drops. The air flows from bottom of the tower or perpendicular to the direction of water flow and then exhausts to the atmosphere after effective cooling.

When the required flow of air and flue gas through a boiler can be obtained by the stack (chimney) alone, the system is called natural draught. When the gas within the stack is hot, its specific weight will be less than the cool air outside; therefore the unit pressure at the base of stack resulting from weight of the column of hot gas within the stack will be less than the column of extreme cool air. The difference in the pressure will cause a flow of gas through opening in base of stack. Also the chimney is form of nozzle, so the pressure at top is very small and gases flow from high pressure to low pressure at the top.

Induced draught: – Here a fan called ID fan is provided at the outlet of boiler, that is, just before the chimney. This fan sucks hot gases from the furnace through the superheaters, economiser, reheater and discharges q card gas station gas into the chimney. This results in the furnace pressure lower than atmosphere and affects the flow of air from outside to the furnace.

iii) Electrostatic precipitator: From air preheater this flue gases (mixed with ash) goes to ESP. The precipitator has plate banks (A-F) which are insulated from each other between which the flue gases are made to pass. The dust particles are ionized and attracted by charged electrodes. The electrodes are maintained at 60KV.Hammering is done to the plates so that fly ash comes down and collect at the bottom. The fly ash is dry form is used in cement manufacture.

We are proud in all our modesty to inform your k electric jobs test good self that we have successfully commissioned the ‘SCALEBAN’ in the 500MW power plant of one of the leading and most reputed power producer of the world i.e. NTPC at their Dadri (U.P.) unit (Please find attached photographs for the same). The installation in the other 500MW power plant will be done in the month of October 2014 during the proposed maintenance shutdown of the concerned power plant.

This is the biggest achievement in the history of Scaleban equipment, as the most reputed power producer of the country has joined hands with us to establish the sustainable, most efficient and cost effective solution for zero discharge with zero scaling. NTPC, after gaining confidence in our technology through in depth study of theoretical aspects and in situ analysis of the performance of the equipment at our client site has joined us in our mission to conserve water with zero scaling.

It is evident that conventional methods for stopping scale deposition in heat ex-changer surfaces are not efficient enough to target this specific problem of the industry. Also the conventional methods available to achieve zero liquid discharge (ZLD) are very costly to establish and operate and so we are encouraged to present our revolutionary technology to help the industry stakeholder to get Scale free condenser/heat ex-changer and to design most efficient, cost effective and sustainable solution for Zero Liquid Discharge (ZLD).

The cooling tower can be operated at very high COC of 15 to 20 as against 3 to 5 of conventional methods. Operations at higher COC will lead to minimization of blow down to almost negligible. There is lot of water conservation involved with use of Scaleban Technology. Practically, uses of Scaleban equipment can conserve water to the tune of more than 25% to 30%. Consumption of fresh water can be brought down by 100% as RO reject and ETP treated water can be directly utilized in cooling tower as make up water instead of soft water. Thus Scaleban has initiated a march towards establishment of a cost effective, most efficient and sustainable solution for the achievement of zero liquid discharge with water conservation and zero scaling.

Both, water and energy are the main area of concern for the industries now a days and gas oil ratio units no one in the world is able to create them; “conserving them is the only way to create them”. Scaleban can proudly claim the maximum conservation of water and energy on account of use of this revolutionary equipment as compared with any other technology available in the world.

-The power plant was commissioned in 1989 and supplied 135 MW. The Delhi State Industrial and Infrastructure Development Corporation (DSIIDC) had been asked to prepare a blueprint for “adaptive reuse”, and the agency presented its proposal in front of Chief Minister Sheila Dikshit and other officials on Wednesday. Dikshit has given in-principle approval to the project, which will require several clearances before it can begin. It will now be presented to the DDA and the DUAC. The project will take about 3 to 4 years to be implemented.

-“Cost of the project is close to Rs 600 crore. It will be a self financing project as power plant equipment will be sold off and also the office space developed inside the plant will be rented out. Rajghat power plant is spread over 46 acre and as per the DSIIDC proposal, 26 acre will be turned into a city forest. The ash pond inside the plant will be enlarged and converted into a waterbody. The soil there is contaminated due to ash depositing here over the years so it would be cleaned before work starts.

-The existing waterbody, which is used by the power plant, will be retained and redeveloped. The plan is to have the forest and the waterbody close to the Salimgarh Fort so that the area can be developed as a tourist spot. The area where coal handling was done will be converted electricity billy elliot broadway into a garden and the main building of the plant will be converted into office space. “We will not touch the outer structure or the envelope of the building. The only changes will be in the interior of the building. Also, demolishing the existing structure will cost more than retrofitting it,” said the official. This is the second power plant site that the government is redeveloping – retrofitting of the Indraprastha Power plant is already underway. Its equipment has already been auctioned.