Components & Working of Thermal Power Plant

Thermal Power Plant

Thermal Power Plants also called Thermal Power Generation Plant or Thermal Power Station.

Definition

“Thermal power plant” as the title infers is the place of mechanism which converts heat energy into electric power.

Thermal Power Plant Working Overview

In thermal power plants, the heat energy obtained from combustion of solid fuel (mostly coal) is used to convert water into steam, this steam is at high pressure and temperature. This steam is used to rotate the turbine blade turbine shaft is connected to the generator. The generator converts the kinetic energy of turbine impeller into electric energy.

Thermal Power Plants and Thermodyne

Thermodyne Engineering Systems has a wide experience in manufacturing boilers that generate high pressure and temperature steam required to rotate the turbine and generate electricity. Along with boiler we also have an experience in providing energy solutions to our customers thereby saving you a lot on the operating cost.

We also do turnkey projects including installation and commissioning of a boiler and its accessories.

Working Components of Thermal Power Plant

Thermal Power Plant consists of a whole set of steps in series for producing electricity.

The fuel is transported from mines via trains to the fuel storage facility in a power plant. The fuel transported to the plant is generally bigger in particle size and before it is fed to the boiler furnace it is broken down into smaller pieces using crushers. The fuel is then fed to the boiler generating a large amount of combustion heat.

On the other hand treated water free from impurities and air is fed to the boiler drum where the combustion heat from the fuel is transferred to water to convert it into high pressure and temperature steam.

Generally, flue gases from the boiler exhaust is at high temperature and if this heat is not utilized will lead to a large amount of losses resulting in reduced boiler efficiencies. So generally this waste heat is recovered by heating either air required for combustion or preheat water before sending it into a boiler.

Flue gases are then allowed to pass through a dust collector or a bag filter to arrest dust particles so as to prevent air pollution before sending it to the atmosphere through a chimney.

Fuel storage and handling plant:

The most essential part of any power plant is to store the fuel safely in an appropriate amount so that the plant can run smoothly in normal days as well as when the supply of fuel from mines is improper. So a fuel storage facility is defined in a plant to store an adequate amount of fuel.

In a thermal power plant, the first step in process of power generation is that the fuel is brought to breaker house with the help of belt conveyor, here light dust is separated with the help of rotary machine through the action of gravity. It further goes to the crusher where it is crushed to a size of about 50mm.

Water treatment plant:

In thermal power, plant water is used in large quantity this water is converted into steam and used to rotate the turbine so this water and steam come into direct contact with the boiler, boiler tubes, boiler accessories and turbine blades.

Normal water is taken from the river, well contains a lot of dirt, suspended particulate matter (SPM), dissolved minerals and dissolved gases such as air etc. If the water fed to the boiler is not treated then it will reduce the life and efficiency of equipment by corroding the surfaces and scaling of equipment which may lead to overheating of pressure parts and explosions.

Suspended matter from the water is removed by adding alum into the water tank through gravity separation. Addition of alum coagulates the suspended particles and due to increase in the density, it settles at the bottom of the tank through gravity.

After gravity separation, water softening is done by ion exchange process. As the hardness comes through the carbonates and bicarbonates of sodium and magnesium, these salts are removed from water anion exchange and cation exchange process.

Water also contains dissolved oxygen and this leads to corrosion and fouling of boiler tubes and surfaces when it comes in their contact. So removing dissolved oxygen from water is done by adding oxygen scavengers and by using a Deaerator tank. Deaerator tank also acts as a feed water tank to store the feed water. On heating feed water in a deaerator tank decreases the solubility of air in water, thereby removing the dissolved air from the water.

“Thermodyne  supplies both Water Softeners and Deaerator tanks to improve the quality of your feed water to the boiler as this improves the life and efficiency of your boiler and its equipment.”

Boiler:

A boiler is a pressure vessel which is used to generate a high-pressure steam at a saturated temperature. At this high pressure and temperature generally, bi-drum water tube boilers are used. Thermodyne Engineering Systems manufactures water tube boilers of various sizes and capacities that can run on various fuels.

Water tube boiler consists of a furnace enclosed by the water tubes membrane. The crushed fuel from the crushers is fed into the boiler furnace over the grate. The hot air from the Forced Draft (FD) fan is mixed with the crushed fuel causing combustion of fuel.

Combustion of fuel generates a lot of radiation heat which is transferred to water in the membrane tubes. Flue gases generated during combustion travel at high velocity across the convection bank of tubes thereby heating water through convection heat transfer. Hot water is sent to a boiler drum at high pressure through the feed water pump.

The boiler tubes which are in contact with low temperature acts as downcomers to circulate the water while the tubes which are in contact with high temperature acts as risers to carry steam. This leads to an effective circulation of water thereby preventing the tubes from getting overheated.

Steam leaving the boiler is at a saturated temperature and pressure but there are a lot of heat losses during its transportation to the turbines. So to increase the quality of steam, steam Superheater is installed in a radiative section of a boiler to increase its temperature and dryness fraction without increasing its pressure as well as to accommodate for the transportation temperature losses.

The exhaust gases leaving the boiler are generally at high temperature and this waste heat is extracted by installing an Economiser or Water Pre heaters to preheat the feed water to the boiler and Air Preheaters to pre-heat the air coming from the Forced Draft Fan required for the combustion of fuel. Installing these equipment help to decrease the flue gas temperature thereby increasing the efficiency.

The flue gases leaving the boiler also contain some ash particles, so to reduce the air pollution, flue gases are allowed to pass through the Dust Collectors and Bag Filters to remove the ash particulates from the flue gases and are sometimes passed through the Wet Scrubbers to decrease the sulfur content from the gases.

The flue gases are drawn through these equipment using an Induced Draft (ID) Fan which is designed for a fixed capacity and head to prevent any back pressure. After the ID fan, flue gases are exhausted off into the atmosphere using a chimney.

Turbine :

A turbine is a mechanical device which converts the kinetic and pressure energy of steam into useful work. From the superheater steam goes to the turbine where it expands and loses its kinetic and pressure energy and rotates the turbine blade which in turn rotates the turbine shaft connected to its blades. The shaft then rotates the generator which converts this kinetic energy into electrical energy.

Other Working Components of Thermal Power Plants

Thermodyne  is a trusted name in Indian Steam Boiler Industry. Backed by more than 15 Yrs of experience and 800+ installations across all major industry segments using boilers.

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