Boiler furnaces

First of all, a technical clarification is necessary in the wider sense, motor fuels are chemical compounds, liquid or gas, which are burned in the presence of air to enable thermal engines to run gasoline, diesel fuel, jet fuels. The term heating fuel is reserved for the production of heat energy in boilers, furnaces, power plants, etc. 

Fig. 6. Cyclone furnace in effect a high, temperature, slag removal combustion chamber auxiliary to the gas-cooling boiler furnace.

Refractories. Its low coefficient of expansion, high thermal conductivity, and general chemical and physical stabihty make sihcon carbide a valuable material for refractory use. Suitable apphcations for sihcon carbide refractory shapes include boiler furnace walls, checker bricks, mufflers, kiln furniture, furnace skid rails, trays for zinc purification plants, etc (see Refractories). 

Industrial furnaces serve the manufacturing sec tor and can be divided into two groups. Boiler furnaces, which are the larger group and are used solely to generate steam, were discussed earlier in the subsec tion on industrial boilers. Furnaces of the other group are classified as follows by (1) source of heat (fuel combustion or electricity), (2) func-... 

The predominant air pollution problem of the nineteenth century was smoke and ash from fhe burning of coal or oil in the boiler furnaces of stationary power plants, locomotives, and marine vessels, and in home heating fireplaces and furnaces. Great Britain took the lead in addressing this problem, and, in the words of Sir Hugh Beaver (3) ... 

Fuel - Fuel supplies to boilers, furnaces, gas turbine and engine drivers, etc., are designed with features such as multiple fuels, propane vaporizer backup, and a liquid fuel surge tank, to promote reliabihty. The failure of any one fuel to a process unit or utihty generation facihty is used as the basis for evaluating a potential overpressure. 

Conduction, convection, and rachation of heat (from boilers, furnaces, forges, etc.) cause tlie ignition of flanunable liquids and combustibles. 

Although some integration has taken place where the appliance or boilermaker has assumed responsibility for the combustion system, overall, specialist manufacturers of combustion equipment who have developed products for each application such as boilers, furnaces, kilns and dryers, etc. serve the market. The burner makers have manufactured products which provide a packaged solution to the combustion requirement, looking after not just the burners and controls but also the fuel supply system, which may involve pumping, heating of the fuel, filtration and other peripheral equipment and functions. 

Volumetric heat release rates The rates of volumetric heat release from shell boiler furnaces fired by oil and gas are typically 175,000 to 235,000 Btu/ft3/hr. (Heat releases from the various tube passes are significantly lower than from the furnace, thus reducing the overall heat-flux rating.)... 

Solid fuels that have not been pulverized require a stoker to introduce the fuel into the boiler furnace at a controlled rate. There are two broad classes of stoker (overfeed and underfeed) and often several types within each class. 

Superheaters and reheaters are tube bundles located in either the boiler furnace section or the convection-pass section. They are designed to increase the temperature of generated steam prior to its being passed to a turbine. Many larger power boiler designs incorporate a steam reheater in addition to one or two banks of superheaters. 

Magnesium-based additives are commonly employed to treat boiler furnace area fouling and corrosion conditions. They are injected into heavy fuel oil or other combustible material. Cerium is superior in action to magnesium salts, however, because an equivalent weight of cerium increases the melting point of the deposit more than that of magnesium. 

Equipment located inside the boiler furnace area to direct the path of hot combustion gases and thus gain maximum heat absorption. 

Any of a number of steel tubes used simultaneously as heat transfer devices for both steam generation and boiler furnace cooling. Boiler tubes may be straight or bent. 

A device used to control the depth of coal entering the boiler furnace in a stoker feed system. 

The regulation of the combustion process in a boiler furnace. Control takes place by regulating the access of fuel or air. 

A boiler furnace. The part where fuel is combusted. 

Heat tolerant brickwork used in boiler furnaces. 

B1. Bagley, R., The application of heat transfer data to the design of once-through boiler furnaces, Proc. Inst. Mech. Engrs. (London) 180, Pt. 3C (1965-1966). 

It has been recognized for some time that fluids in motion, such as the atmosphere or the ocean, disperse added materials. This properly has been exploited by engineers in a variety of ways, such as the use of smoke stacks for boiler furnaces and ocean ontfalls for the release of treated wastewaters. It is now known that dilution is seldom the solution to an enviromnental problem the dispersed pollutants may accumulate to undesirable levels in certain niches in an ecosystem, be transformed by biological and photochemical processes to other pollntants, or have nnanticipated health or ecological effects even at highly dilute concentrations. It is therefore necessary to rmderstand the transport and transformation of chemicals in the natural environment and through the trophic chain ctrlminating in man. 

Thermal Process Studsvik (TPS) (Studsvik Eneriteknik AB) Woody biomass LHV Fuel gas, duel fuel engine, gas turbine, boiler/furnace/ kiln fuel 13-78 (upper limit commercial) 14.7... 

CycUme Furnaces In cyclone firing (Fig. 24-l4d) the coal is not pulverized but is crushed to 4-mesh (4.76-mm) size and admitted tangentially with primary air to a horizontal cylindrical chamber, called a cydone furnace, which is connected peripherally to a boiler furnace. Secondary air also is admitted, so that most all of the coal bums within the chamber. The combustion gas then flows into the boiler furnace. In the cyclone furnace, finer coal particles burn in suspension and the... 

Historical. The gases from a blast furnace, the smoke-stacks from boiler furnaces, cement plants, etc carry with.them solid particles in the form of dust. While the greater part of this dust may be recovered by passing the gases thru a dust collector , such as shown in Fig 242 of Ref 3, p 720 (our Fig E27) there are dusts, however, too fine to settle in the collector. The dust collector provides a... 

In fire-tube furnaces developed in the nineteenth century, such as typified by the Scotch-Marine boiler (Fig. 1), thin currents of water contact a multiplicity of tubes thus, the hot gases transmit heat simultaneously to all regions of the bulk of the water. Therefore, this boiler—furnace combination steams readily and responds promptly to load changes, and is, for a given amount of heating surface, the least expensive of all furnace—boiler installations... 

Many of the problems in combustion research stem from the difficulty of burning in combustors at high speeds and altitudes. The advances in this field have been tremendous. The jet-turbine combustor will release 500 times the energy for a given space as the stationary boiler furnace. Its operating problems have been overcome (with the usual partial aid of fundamental combustion research) so that the limiting operational altitudes of aircraft are well above 50,000 feet and the speeds are supersonic. 

Air is the usual source of oxygen for boiler furnaces. These combustion reactions are exothermic as indicated by the foregoing equations. 

This description deals with the basic chemistry necessary for understanding Ihe phenomena of combustion in boiler furnaces. Ability to calculate the release of heat in combustion and to determine the amount and nature of the combustion products is essential for the design, for example, of a steam generating plant and determination of its performance characteristics. 

In a boiler furnace (where no mechanical work is done) the heal energy evolved from the union of combustible elements with oxygen depends on the ultimate products of combustion and not on any intermediate combinations that may occur in reaching the final result. 

Molten ash is one of the products of combustion of coal in certain liigli-capacity boiler furnaces. It is also called slag. In some plants, the ash is removed from the furnace in this fluid form. Such furnaces are known as slag tap furnaces. Slag has some commercial value as ballast, coarse aggregate for concrete, road metal, etc. 

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