Coal-fired plants produce electricity by burning coal in a boiler to produce steam. The steam produced, under tremendous pressure, flows into a turbine, which spins a generator to create electricity. The steam is then cooled, condensed back into water and returned to the boiler to start the process over.
How do you calculate coal fired boiler efficiency?
In direct method, the efficiency is evaluated by dividing the heat output with the fuel power (input) of the boiler, whereas indirect method considers the ratio of sum of major losses to the fuel power input of the boiler, which will be finally subtracted from unity .
What do you mean by pulverization of coal?
In a pulverized coal combustion process, the coal is ground to talcum-powder fineness, and injected through burners into the furnace with combustion air. The fine coal particles heat up rapidly, undergo pyrolysis and ignite. The bulk of the combustion air is then mixed into the flame to completely burn the coal char.
What causes clinkers in a coal fired boiler?
Coal clinkers form when noncombustible elements contained in coal such as iron, calcium, silicon, aluminum and sodium interact with sulfur and carbon at high temperatures. These elements melt together with clays and alkalis to form a glassy slag that eventually hardens into clinkers.
In what form is the coal used in boiler?
Bituminous coal is commonly used in power plant boilers for generation of electric power.
How efficient is coal?
With coal-fired power plants achieving an average 33 percent efficiency, it’s crucial to build advanced HELE plants to reduce global carbon emissions. … The International Energy Agency predicts that coal will generate more electricity in 2040 than all new renewable technologies (excluding hydro) combined.
What is boiler efficiency?
Definition of Boiler Efficiency is “The percentage of the total absorption heating value of outlet. steam in the total supply heating value.” In other word, it is a rate how the boiler runs efficiently.
Why is coal crushed before burning?
The concept of burning coal that has been pulverized into a fine powder stems from the belief that if the coal is made fine enough, it will burn almost as easily and efficiently as a gas. … As the coal gets crushed by the rolling action, the hot air dries it and blows the usable fine coal powder out to be used as fuel.
What is pulverization process?
Definition of pulverization
“Pulverization” (comminution, crushing, grinding) is the process of applying an external force to a (solid) material of a certain size to destroy it and reduce it into pieces that are smaller than the original size.
What is left after coal?
Coal ash is the powdery substance that remains after burning coal. … The sludge, which is created from solutions sprayed inside exhaust stacks to capture the harmful chemicals that cause acid rain, sulfur dioxide and nitrogen oxide, falls to the bottom.
What are clinkers in coal?
Clinker coal is the result of a seam of coal catching fire and burning so hot that it baked surrounding rock layers into brick-like formations.
Do you need a chimney for a coal stove?
Generally, wood stoves and coal stoves do need chimneys to vent properly. Some coal stoves can be direct-vented out through a side wall but it is always preferable to have a chimney to ensure it functions properly.
What causes clinkers?
When wood is pelletized for use in pellet-burning stoves, those impurities can result in “clinkers.” A clinker is a particle that isn’t burned during the normal combustion process. … Clinkers can also form when minerals in the ash fuse together or when dirt is introduced into the combustion chamber.
What are the 5 types of coal?
Coal is classified into four main types, or ranks: anthracite, bituminous, subbituminous, and lignite. The ranking depends on the types and amounts of carbon the coal contains and on the amount of heat energy the coal can produce.
What is boiler used for?
Boilers are used to produce steam. The generation part of a steam system uses a boiler to add energy to a feedwater supply to generate steam. The energy is released from the combustion of fossil fuels or from process waste heat.