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Tangential firing is a method of firing a fuel to heat air in thermal power stations. The flame envelope rotates ensuring thorough mixing within the furnace, providing complete combustion and uniform heat distribution.
The most effective method for producing intense turbulence is by the impingement of one flame on another. This action is secured through the use of burners located in each of the four corners of the furnace, close to the floor or the water-screen. The burner nozzles are so directed that the streams of coal and air are projected along a line tangent to a small circle, lying in a horizontal plane, at the center of the furnace. Intensive mixing occurs where these streams meet. A scrubbing action is present which assures contact between the combustible and oxygen, thus promoting rapid combustion and reducing carbon loss. A rotative motion, similar to that of a cyclone, is imparted to the flame body, which spreads out and fills the furnace area. The ignition at each burner is aided by the flame from the preceding one.
With tangential firing the furnace is essentially the burner, consequently air and coal quantities need not be accurately proportional to the individual fuel nozzle assemblies. Turbulence produced in the furnace cavity is sufficient to combine all the fuel and air. This continuously ensures uniform and complete combustion so that test performance can be maintained throughout daily operation. With other types of firing the fuel and air must be accurately proportioned to individual burners making it difficult to always equal test results.
With this type of firing, combustion is extremely rapid, and short flame length results. The mixing is so intense that combustion rates exceeding 35,000 Btu/(ft3·h) or 360 kW/m3 are practical under certain conditions. However, since there is considerable impingement of flame over the furnace walls it is absolutely necessary that they be fully water-cooled. This sweeping of the water-cooled surfaces, in the furnace, by the gas increases the evaporation rate. Thus, in addition to absorption by radiation from the flame envelope, there is transfer by convection, and the resulting furnace temperatures are lower than with other types of burners, even though the heat liberation rates may be somewhat higher. Tangentially fired furnaces are usually clean in the upper zone and, as a result, both the furnace and the boiler are comparatively free from objectionable slag deposits. [1]
A Bunsen burner, named after Robert Bunsen, is a kind of gas burner used as laboratory equipment; it produces a single open gas flame, and is used for heating, sterilization, and combustion.
A boiler is a closed vessel in which fluid is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central heating, boiler-based power generation, cooking, and sanitation.
A furnace, referred to as a heater or boiler in British English, is an appliance used to generate heat for all or part of a building. Furnaces are mostly used as a major component of a central heating system. Furnaces are permanently installed to provide heat to an interior space through intermediary fluid movement, which may be air, steam, or hot water. Heating appliances that use steam or hot water as the fluid are normally referred to as a residential steam boilers or residential hot water boilers. The most common fuel source for modern furnaces in North America and much of Europe is natural gas; other common fuel sources include LPG, fuel oil, wood and in rare cases coal. In some areas electrical resistance heating is used, especially where the cost of electricity is low or the primary purpose is for air conditioning. Modern high-efficiency furnaces can be up to 98% efficient and operate without a chimney, with a typical gas furnace being about 80% efficient. Waste gas and heat are mechanically ventilated through either metal flue pipes or polyvinyl chloride (PVC) pipes that can be vented through the side or roof of the structure. Fuel efficiency in a gas furnace is measured in AFUE.
A fire-tube boiler is a type of boiler in which hot gases pass from a fire through one or more tubes running through a sealed container of water. The heat of the gases is transferred through the walls of the tubes by thermal conduction, heating the water and ultimately creating steam.
In a steam engine, the firebox is the area where the fuel is burned, producing heat to boil the water in the boiler. Most are somewhat box-shaped, hence the name. The hot gases generated in the firebox are pulled through a rack of tubes running through the boiler.
A combustor is a component or area of a gas turbine, ramjet, or scramjet engine where combustion takes place. It is also known as a burner, combustion chamber or flame holder. In a gas turbine engine, the combustor or combustion chamber is fed high-pressure air by the compression system. The combustor then heats this air at constant pressure. After heating, air passes from the combustor through the nozzle guide vanes to the turbine. In the case of a ramjet or scramjet engines, the air is directly fed to the nozzle.
A cyclone furnace is a type of coal combustor commonly used in large industrial boilers.
A thermal power station is a power station in which heat energy is converted to electricity. Typically, fuel is used to boil water in a large pressure vessel to produce high-pressure steam, which drives a steam turbine connected to an electrical generator. The low-pressure exhaust from the turbine passes through a steam condenser and is recycled to where it was heated. This is known as a Rankine cycle. Natural gas can also be burnt directly in a gas turbine similarly connected to a generator.
An air preheater is any device designed to heat air before another process (for example, combustion in a boiler With the primary objective of increasing the thermal efficiency of the process. They may be used alone or to replace a recuperative heat system or to replace a steam coil.
A forced-air central heating system is one which uses air as its heat transfer medium. These systems rely on ductwork, vents, and plenums as means of air distribution, separate from the actual heating and air conditioning systems. The return plenum carries the air from several large return grills (vents) to a central air handler for re-heating. The supply plenum directs air from the central unit to the rooms which the system is designed to heat. Regardless of type, all air handlers consist of an air filter, blower, heat exchanger/element/coil, and various controls. Like any other kind of central heating system, thermostats are used to control forced air heating systems.
A pulverized coal-fired boiler is an industrial or utility boiler that generates thermal energy by burning pulverized coal that is blown into the firebox.
A pulverizer or grinder is a mechanical device for the grinding of many different types of materials. For example, a pulverizer puritch is used to pulverize coal for combustion in the steam-generating furnaces of coal power plants.
An oil burner is a heating device which burns #1, #2 and #6 heating oils, diesel fuel or other similar fuels. In the United States ultra low #2 diesel is the common fuel used. It is dyed red to show that it is road-tax exempt. In most markets of the United States heating oil is the same specification of fuel as on-road un-dyed diesel.
Recovery boiler is the part of Kraft process of pulping where chemicals for white liquor are recovered and reformed from black liquor, which contains lignin from previously processed wood. The black liquor is burned, generating heat, which is usually used in the process of making electricity, much as in a conventional steam power plant. The invention of the recovery boiler by G.H. Tomlinson in the early 1930s was a milestone in the advancement of the kraft process.
Staged combustion is a method used to reduce the emission of nitrogen oxides (NOx) during combustion. There are two methods for staged combustion: air staged supply and fuel staged supply. Applications of staged combustion include boilers and rocket engines.
High Marnham Power Station was a coal-fired power station in Nottinghamshire, to the west of the River Trent, approximately 0.5 miles (0.8 km) north of the village of Marnham. Construction began in 1954, power generation commenced in 1959, and the station became fully operational in 1962. The plant operated until 2003 when it was decommissioned, though the cooling towers weren't demolished until 2012.
A Meker–Fisher burner, or Meker burner, is a laboratory burner that produces multiple open gas flames, used for heating, sterilization, and combustion. It is used when laboratory work requires a hotter flame than attainable using a Bunsen burner, or used when a larger-diameter flame is desired, such as with an inoculation loop or in some glassblowing operations. The burner was introduced by French chemist Georges Méker in an article published in 1905.
A coal burner is a mechanical device that burns pulverized coal into a flame in a controlled manner. Coal burner is mainly composed of pulverized coal machine, host of combustion machine control system, ignition system, the crater and others.
Computational fluid dynamics (CFD) are used to understand complex thermal flow regimes in power plants. The thermal power plant may be divided into different subsectors and the CFD analysis applied to critical equipment/components - mainly different types of heat exchangers - which are of crucial significance for efficient and trouble free long-term operation of the plant.
An industrial furnace, also known as a direct heater or a direct fired heater, is a device used to provide heat for an industrial process, typically higher than 400 degrees Celsius. They are used to provide heat for a process or can serve as reactor which provides heats of reaction. Furnace designs vary as to its function, heating duty, type of fuel and method of introducing combustion air. Heat is generated by an industrial furnace by mixing fuel with air or oxygen, or from electrical energy. The residual heat will exit the furnace as flue gas. These are designed as per international codes and standards the most common of which are ISO 13705 / American Petroleum Institute (API) Standard 560. Types of industrial furnaces include batch ovens, vacuum furnaces, and solar furnaces. Industrial furnaces are used in applications such as chemical reactions, cremation, oil refining, and glasswork.
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