: a wide endless traveling chain that feeds and supports the fuel in a boiler furnace.

What is Travelling Grate stoker?

[′trav·əl·iŋ ¦grāt ′stō·kər] (mechanical engineering) A type of furnace stoker; coal feeds by gravity into a hopper located on top of one end of a moving (traveling) grate; as the grate passes under the hopper, it carries a bed of fresh coal toward the furnace.

What are the various types of stokers used for coal firing?

• Also called Mechanical Stokers.
• Travelling Grate Stoker.
• Chain Grate Stoker.
• Spreader Stoker.
• Vibrating Stoker.
• Underfeed Stoker.

What is grate in thermal power plant?

A furnace grate is provided in a steam boiler furnace for supporting the solid fuel in the furnace. Grate is so designed that it can also allow air to admit air in the solid fuel for combustion.

What is meant by overfeed and underfeed principle of coal firing?

Overfeed stoker is the type of stoker in which the coal is fed from the top and air is blown from below. Underfeed stoker is one where coal is fed from underneath and the air is fed from top.

What are types of boiler?

• Shell and tube boilers. Shell and tube boilers are also referred to as fire tube or smoke tube boilers. …
• Different types of fire tube boilers: …
• Lancashire boiler: …
• Locomotive boiler. …
• Reversal Chamber: …
• Wet Back Boilers: …
• Dry Back Boilers: …
• Two pass boilers:

How coal is pulverized?

Pieces of coal are crushed between balls or cylindrical rollers that move between two tracks or “races.” The raw coal is then fed into the pulverizer along with air heated to about 650 °F (340 °C) from the boiler. … The powdered coal from the pulverizer is directly blown to a burner in the boiler.

What is the function of grate?

Gratings over drains and air vents are used as filters, to block movement of large particles (such as leaves) and to allow movement of small particles (such as water or air).

What is Stoker power plant?

stoker, machine for feeding coal or other solid fuel into a furnace, usually supporting the fuel during combustion. … Power for running a stoker is usually furnished by an electric motor, and control of combustion is achieved by variable speed or intermittent drive.

What is grate system?

Grate firing is a type of industrial combustion system used for solid fuels. It now is used mainly for burning waste and biomass, but also for smaller coal furnaces.

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What is stoker coal?

Stoker coal refers to coal that has been crushed to specific sizes (but not powdered) for burning on a grate in automatic firing equipment.

How does the chain run in Travelling Grate Stoker?

How does the chain run in travelling grate stoker? Explanation: The chain travels over two sprockets. In both chain type and in bar type stokes. One sprocket is placed at the front end and other sprocket is placed at the rear end of the furnace.

What is overfeed Fuelbed?

In case of overfeed stokers, the coal is fed on the grate above the point of air admission. … The water vapour present in the air also reacts with coke to form CO, CO2 and H2. The gases leaving the fuel bed contain the N2, CO2, CO, H2 and H2O. Then additional air is supplied to burn the combustible gases.

What is pulverized fuel firing?

We refer the process of making the fuel powder as pulverization. … This pulverized coal gets sprayed in the combustion chamber with a blow of hot air. The air used to spray the coal into the combustion chamber must get dry before entering the chamber.

How is the fuel selected in the pulverized fuel system?

Explanation: Most of the large power plants use pulverized fuel firing system since it is higher in its thermal efficiency. And selection of it mainly depends upon the size of boiler unit, type of the coal available, nature of load on the plant, load factor, cost of the fuel and availability of skilled labors.

Why is mechanical handling of fuel necessary in power plant?

Mechanical Stoker Firing: Even though it is costlier, generally they are used to feed the solid fuels in small and medium size power plants, because of the following reasons: 1) Combustion is more efficient. 2) Fuel handling is automatic and combustion control is easier. 3) Faster response to load fluctuations.

What do you mean by pulverized?

1 : to reduce (as by crushing, beating, or grinding) to very small particles : atomize pulverize rock. 2 : annihilate, demolish. intransitive verb. : to become pulverized.

What is pulverized coal combustion?

Pulverised coal (PC) combustion is the most widely used technology for utility-scale power generation in the world. In PC boilers, coal is ground into fine particles (∼100 μm) and then injected with heated combustion air through a number of burners into the lower part of the furnace.

What do you understand by pulverized coal What are its advantages?

Advantages of pulverized coal It increases the efficiency of the boiler. It makes possible the use of wide variety of coal. It reduces time of raising temperature of steam. Combustion of pulverized coal can readily be adopted to automatic control.

What are the 3 types of boilers?

There are three main types of boilers you can install into your home: combi boilers, heat only (regular boilers) and system boilers.

How are boiler classified?

Boilers are classified into different types based on their working pressure and temperature, fuel type, draft method, size and capacity, and whether they condense the water vapor in the combustion gases. … Two primary types of boilers include Fire- tube and Water- tube boilers.

What is boiler PDF?

A steam boiler is a closed vessel, generally made of steel, in which water is heated by some source of heat produced by combustion of fuel and ultimately to generate steam. The steam produced may be supplied at low pressure for industrial process work in cotton mills, sugar industries etc.

How does a stoker work?

A mechanical stoker is a mechanical system that feeds solid fuel like coal, coke or anthracite into the furnace of a steam boiler. … The under feeder pushes fresh coal into the bottom of the furnace and then advances it upwards so that it mixes with the burning coal above.

What are the principal of stokers?

Explanation: In under feed type of stokers, the fuel and air move in the same direction. In this stoker air after passing through the holes in the grate comes in contact with the raw coal. As air diffuses through the bed of raw coal, it mixes with the volatile matter generated by the raw coal.

What is grating in?

In optics, a diffraction grating is an optical component with a periodic structure that diffracts light into several beams travelling in different directions (i.e., different diffraction angles). The emerging coloration is a form of structural coloration.

What is grating in drains?

Trench drain grates, sometimes called channel grates, cover an elongated horizontal trench drain rather than a single round drain pipe. … The drain consists of a horizontal trench that is open on top; the trench grate covers the top of the trench and allows water to flow into the drain along the its entire length.

What is grate and ash pit?

: a pit for ashes especially under a grate.

What are sewer grates called?

Large sewer grates, sometimes referred to as manhole covers, are the grates that can be found on roads and highways. Everything that drains down into these sewers usually ends up in the public sewer system. Although they are heavy and cumbersome, large manhole covers are stolen right from city streets.

What is heel proof?

The term “Heel Proof” is used quite often when selecting trench drain grates. This term generally refers to the attempt to keep the heel of a woman’s shoe out of the trench grate opening.

Where grate is located in boiler?

A grate in a boiler is a place in the combustion chamber upon which fuel wood or coal is burnt.

What is treated stoker coal?

Welcome. Smaller sizes of coal like stoker coal (some call it slack coal or furnace coal) or pea/nut sized coal, are oil treated to help control dust. These smaller sizes of oil treated coals are best suited to be burned in automated auger feed type furnaces. For hand fired stoves, lump coal would be what I recommend.