Coal fired boiler types pdf

Whereas this system was designed to describe deposits from coalfired steam generators, it may be applied to other environments or equipment. Coal fired boiler is widely used to generate thermal energy by burning fuel in the firebox. Although coal is primarily a mixture of carbon black and hydrogen red atoms, sulfur atoms yellow are also trapped in coal, primarily in two forms. Pulverized fuel boilerpulverized fuel boiler generate thermal energy by burning pulverized coal powdered coal or coal dust. Blowdown protects boiler surfaces from severe scaling or corrosion problems that can result otherwise. How to run a coal fired boiler at the best efficiency. There are a considerable number of ways to feed coal in use, including, handfired boilers, chain or traveling grate stokers, vibrating grate stokers, underfeed stokers, spreader stoker, pulverized coal boilers, cyclone boilers and fluidized bed boilers. Pulverized coal powder blown with combustion air into boiler through burner. Continue to next page 17 the cost of cycling coal fired power plants figure 2. This design allows for air to enter and escape during filling and draining of the boiler. In case of combustion type furnace, depending upon the kind of combustion, it can be broadly classified as oil fired, coal fired or gas fired.

From a thermophysics perspective, two phase mixtures of water and steam are replaced by a single supercritical fluid when the boiler pressure increases above the critical pressure of 22. Estimates of emissions from coal fired thermal power. Pulverized coal firing is the method of choice for large industrial boilers e. As grate moves along the length of the boiler furnace, the coal burns before dropping off at. Classification of steam boilers boiler classification can be based on many factors like usage, fuel fired, fuel firing system, type of arrangement etc. Commonly known types are pulverized coal fired boilers, fluidized bed boilers, super critical boilers, oil and gas fired boilers. A large thermoelectric plant like this burns a lot of coalin this case, about 11 million tons per year. Boiler fuels, emissions and efficiency ced engineering. The pollutants emitted from thermal power plants depend largely upon the characteristics. The purpose of boiler blowdown is to control solids in the boiler water. As expected, the supercritical boilers averaged a lower heat rate than the subcritical boilers. As the national hitech enterprise certificated by the government and the 500 largest machinery industrial enterprises, taishan group had been dedicated in supplying turn key coal fired boiler and industrial boiler solutions to worldwide customers since in 1994.

It rapidly breaks down in water to form calcium hydroxide caoh 2 and is carried by rainwater to the water bodies from the slag dump zones. Zbg is a reliable boiler manufacturer with 71 years history and experience in all types of boilers designing and manufacturing. Coal flow biasing for making uniform temperature distribution in reheater 752010 cfd modeling of 500 mw tangential coal fired boiler page 51 15% flow. Over the past two decades, existing plants have been phasing out pond. Types of coal there are various types of coal, from anthracite with its high carbon content to bituminous coal, subbituminous coal and lignite brown coal, which is an even younger coal. Boiler types according to the type of fuel used or fuelburning methods coal fired boilers, oil fired boilers, gas fired boilers, biomass boilers, electric boilers circulating fluidized bed boiler fbc boiler.

Coal that has been ground into a fine powder by a pulverizer is blown into a furnacelike device, called a boiler, and burned. Life cycle assessment of coalfired power production. Different types of coal fired steam boilers for power stations. Boilers that operate higher than 15 psig are called highpressure boilers. With this information the operators are able to minimize damage, maximize the assets life and reliability while reducing maintenance costs. Air preheaters aph air preheaters aph is the shell and tube type heat exchangers used for preheating the air which is fed to the boiler or furnaceskilns for combustion of fuels. Types of boiler furnaces coalfired boilers can be classified regarding the type of a furnace. Coal and oilfired steam power plants have steam turbines to convert the heat energy of combustion into mechanical energy, which then operates an electric generator. Coal boilers are commonly used to heat water and create steam for energy production. In one form, the sulfur is a separate particle often linked with iron green with no connection to the carbon atoms, as in the center of the drawing. Stoker fired boiler are classified according to the method of feeding fuel to the furnace and by the type of grate. Coalfired boilers are mainly operated at either subcritical or supercritical conditions. A boiler or steam generator is a device used to create steam by applying heat energy to water. Although the definitions are somewhat flexible, it can be said that older steam generators were commonly termed boilers and worked at low to medium pressure 72,000 kpa or 1290 psi but, at pressures above this, it is more usual to speak of a steam generator.

Pulverizedcoalfired boilers emit between 70 and 85 percent of the ash in the coal as fly ash. Different types of coal fired steam boilers for power. 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. Coal fired boiler, biomass boiler designer and manufacturer. Cofiring biomass and coal is a timetested fuelswitching strategy that is particularly well suited to a stoker boiler, the type most often found at coalfired federal facilities. Due to pulverization, the surface area of coal becomes much larger, and in this method air required for combustion is much less. Evaluation of heat rates of coal fired electric power boilers. Different types of coal fired steam boilers for power stations 20161008 16. Boilers bureau of energy efficiency 27 syllabus boilers. Coal, petroleumbased oils, and natural gas are fossil fuels commonly fired in ici boilers. Coal burns in suspension, like the combustion in an oil or gasfired boiler. The combustion process of the pulverized coal in the boiler is a complicated nonlinear phenomenon. Pulverized coal fired pcf boilers general information coalfired water tube boiler systems generate approximately 38% of the electric power generation worldwide and will continue to be major contributors in the future.

A hot water boiler, strictly speaking, is not a boiler. Coal pulverizers are the notable materialhandling component largely unique to coal. A pulverized coalfired boiler is an industrial or utility boiler that generates thermal energy by burning pulverized coal also known as powdered coal or coal dust since it is as fine as face powder in cosmetic makeup that is blown into the firebox the basic idea of a firing system using pulverised fuel is to use the whole volume of the furnace for the combustion of solid fuels. This technology is well developed, and there are thousands of units around the world, accounting for well over 90% of coalfired capacity. Pulverized coal fired boilers, which are the most popular utility boilers today, have a high efficiency but a costly sox and nox. All plants use the steam turbine for the drop between the high pressure and temperature of the steam and the lower pressure of condensing vapor. Chapter three coalfired power plant designs, systems. Coal can provide lower operating costs in comparison to other fossil fuels like oil or natural gas, it is one of the cleanest fossil fuels available today due to the state of the art computerized pulverized coal handling and combustion technology. Pulverized coal fired pcf boilers general information coal fired water tube boiler systems generate approximately 38% of the electric power generation worldwide and will continue to be major contributors in the future.

Mostly fire tube boilers are of package type boilers they produce less amount less pressure of steam than water tube boilers. Different types of coal fired steam boilers are supplied by us for power stations. However, cofiring has been successfully demonstrated and practiced in all types of coal boilers, including pulverizedcoal boilers, cyclones, stokers, and fluidized. Coal is pulverized in some type of large mill pulverized coal is fired out into the furnace. Power generating equipment needs to be optimized for these different types of coal. This video describes the complete demonstration that how coal fired boiler actually works by an animated video. For steam turbinedriven cases, the exhaust is directed to the lp turbine condenser. Coalfired boiler efficiency can often provide lower operating costs in comparison to other fossil fuels almost 75% less than oil or natural gas. Oak ridge national laboratory may 2005 submitted by. Coal fired boilers coal fired boiler, biomass boiler. Equipment replacements versus starts for a 600 mw coalfired unit.

Boiler feedwater is pressurized with a single hp boiler feedwater pump bfp, powered by an electric drive for the 400 and 600mw cases and a steam turbine drive for the 900mw case. Pulverized fuel firing is most modern and efficient method of boiler firing. Boilers are classified as highpressure or lowpressure and steam boiler or hot water boiler. Bituminous coal is harder and blacker than lignite and subbituminous coal, and can be divided into two types. The steam produced may be supplied at low pressure for industrial process work in cotton mills, sugar industries etc. The heat produced converts water, which runs through a. Coal analysis for boiler designers hydrocarbon fuels are the.

Before firing a cold boiler with no steam pressure, open the air cock to allow air to figure 91boiler fittings. Pulverized fuel boiler most coalfired power station boilers use pulverized coal, and many of the larger industrial watertube boilers also use this pulverized fuel. In 20, nrdc analyzed boiler heat rates and applied a modeling methodology that grouped the. Air pre heaters primary objective is to extract the waste heat from the flue gases leaving the boiler. Industrialcommercial boiler population submitted to. Sometimes, combinations of fuels are used to reduce emissions or improve boiler performance. In the late 1970s, dry fly ash collection systems began growing in popularity, especially for new coalfired installations. An air cock is located in the uppermost steam space of a boiler, as shown in figure 92.

In travelling grate boiler coal is fed at one end of a moving steel chain grate. Boiler types and classifications wiki odesie by tech. Types, combustion in boilers, performances evaluation, analysis of losses, feed water treatment, blow down, energy conservation opportunities. A continuous blowdown uses a calibrated valve and a blowdown tap near the boiler water surface.