Fired furnace

White phosphorus may be made by several methods. By one process, tri-calcium phosphate, the essential ingredient of phosphate rock, is heated in the presence of carbon and silica in an electric furnace or fuel-fired furnace. Elementary phosphorus is liberated as vapor and may be collected under phosphoric acid, an important compound in making super-phosphate fertilizers. 

Fuel economy Fuel-fired furnaces Fuel gas Fuel oil... 

Furnaces, fuel-fired Furnaces, induction Furniture... 

It is useful to examine the combustion process appHed to soHd wastes as fuels and sources of energy. AH soHd wastes are quite variable in composition, moisture content, and heating value. Consequendy, they typically are burned in systems such as grate-fired furnaces or duidized-bed boilers where significant fuel variabiUty can be tolerated. 

Fuel-fired furnaces primarily utilize carbonaceous or hydrocarbon fuels. Since the purpose of a furnace is to generate heat for some useful appHcation, flame temperature and heat transfer are important aspects of furnace design. Heat transfer is impacted by the flame emissivity. A high emissivity means strong radiation to the walls. 

The analytical mechanisms for predicting the corresponding pollutant formation associated with fossil-fuel-fired furnaces lag the thermal performance prediction capabiUty by a fair margin. The most firmly estabUshed mechanism at this time is the prediction of thermal NO formation (24). The chemical kinetics of pollutant formation is, in fact, a subject of research. 

PPS fiber has excellent chemical resistance. Only strong oxidising agents cause degradation. As expected from inherent resia properties, PPS fiber is flame-resistant and has an autoignition temperature of 590°C as determined ia tests at the Textile Research Institute. PPS fiber is an excellent electrical iasulator it finds application ia hostile environments such as filter bags for filtration of flue gas from coal-fired furnaces, filter media for gas and liquid filtration, electrolysis membranes, protective clothing, and composites. 

Vitreous silica is used for gas-heated or electrically heated devices ia various shapes, eg, as a tube or muffle because of its electrical resistivity, impermeabihty, and low expansion. In its simplest form, an electric-resistance furnace consists of a vitreous siUca tube or pipe on which the resistance element is wound (see Furnaces, ELECTRIC). Because of its iadifference to temperature gradients, a tubular furnace of vitreous siUca maybe made to operate at different temperatures at various portions of the tube, either by arrangement of the heating elements or by cooling sections of the tube with water. Vitreous siUca pipes may be employed ia vacuum-iaduction and gas-fired furnaces (see Vacuum technology) (221). 

Furnaces for Oil and Natural Gas Firing. Natural gas furnaces are relatively small in size because of the ease of mixing the fuel and the air, hence the relatively rapid combustion of gas. Oil also bums rapidly with a luminous flame. To prevent excessive metal wall temperatures resulting from high radiation rates, oil-fired furnaces are designed slightly larger in size than gas-fired units in order to reduce the heat absorption rates. 

Instead of gas turbine exhaust, air preheat has been used in some plants to reduce fuel consumption. Flue gas leaving the furnace stack passes through an air preheater, and the preheated air is suppHed to the burners. By using mostly hearth burners, the duct work and the investment cost can be minimised with air preheat and gas turbine exhaust. It is also possible with 100% waH-fired furnaces, and has been proven in commercial operation (34). 

REIST Aerosol Science and Technology, Second Edition RHINE, TUCKER Modeling of Gas-Fired Furnaces and Boilers and Other Industrial Heating Processes ROSSITER Waste Minimization Through Process Design SAMDANI Safety and Risk Management Tools and Techniques in the CPI... 

Knowledge of the composition of coal ash is usehil for estimating and predicting coal performance in coke making and, to a hmited extent, the folding and corrosion of heat-exchange surfaces in pidverized-coal-fired furnaces. 

The circular burner shown in Fig. 27-17 is widely used in horizontally fired furnaces and is capable of firing coal, oil, or gas in capacities as tigh as 174 GJ/h (1.65 X 10 Btii/h). In such burners the air is often swirled to create a zone of reverse flow immediately downstream of the burner centerline, which provides for combustion stability. 

An advantage of a stoker-fired furnace is its easy adaptability to firing almost any unsized solid fuels. Bark, bagasse, or refuse can normally be fired on a stoker to supplement the coal with a minimum amount of additional equipment. Thus, such supplementaiy waste fuels may be able to contribute a higher percentage of the total heat input in a stoker-fired furnace than in a PC furnace without expensive equipment modifications. 

The failure took place in a large water-tube boiler used for generating steam in a chemical plant. The layout of the boiler is shown in Fig. 13.1. At the bottom of the boiler is a cylindrical pressure vessel - the mud drum - which contains water and sediments. At the top of the boiler is the steam drum, which contains water and steam. The two drums are connected by 200 tubes through which the water circulates. The tubes are heated from the outside by the flue gases from a coal-fired furnace. The water in the "hot" tubes moves upwards from the mud drum to the steam drum, and the water in the "cool" tubes moves downwards from the steam drum to the mud drum. A convection circuit is therefore set up where water circulates around the boiler and picks up heat in the process. The water tubes are 10 m long, have an outside diameter of 100 mm and are 5 mm thick in the wall. They are made from a steel of composition Fe-0.18% C, 0.45% Mn, 0.20% Si. The boiler operates with a working pressure of 50 bar and a water temperature of 264°C. 

Steam stripping is not adequate for the bottoms purity required. More positive stripping is obtained by charging the tower bottom liquid to a heating unit known as a reboiler. In a typical reboiler, 50% of the feed is vaporized and returned to the tower below the bottom plate. A fractionating tower equipped with a steam heated reboiler is shown in Figure 4. The reboiler may also be heated by a hot oil stream, such as a pumparound reflux stream from the primary fractionator of a cracking unit, or by a fired furnace. 

Some gas processes use direct fired furnaces. Process fluid flows inside tubes that are exposed to a direct fire. In this case radiant energy is important. Furnaces are not as common as other devices used in production facilities because of the potential fire hazard they represent. Therefore, they are not discussed in this volume. 

Feuer, n. fire furnace, hearth, forge light (as for a signal), beacon. 

The main use of residual fuel oil is for power generation. It is burned in direct-fired furnaces and as a process fuel in many petroleum and chemical companies. Due to the low market value of fuel oil, it is used as a feedstock to catalytic and thermal cracking units. 

Combustion/ Solid fuel-fired furnaces Fuel in direct contact Recuperative Manual and Batch, periodic Natural/self, Crucible, shaft Melting roasting Shaft, muffle... 

Gaseous fuel-fired furnaces Multi fuel-fired furnaces heated by-products of combustion. Material is heated by heat transfer draught furnaces ... 

The reactor used for the aluminothermic reduction of niobium pentoxide is shown schematically in Figure 4.17 (A). It is a steel pipe, lined on the inside with alumina and provided with a pipe cap. The charge, consisting of stoichiometric amounts of niobium pentoxide and aluminum powder, is blended and loaded in the lined pipe, and covered with alumina. The cap is closed and the reaction initiated by placing the loaded bomb in a gas-fired furnace, preheated to 800 °C, and by raising the temperature of the furnace to 1100 °C. 

Conventional riffle box, as shown in Fig. 24, used normally for 2-way splitting in coal-fired furnace and boiler applications. 

Steam reforming is traditionally carried out in large fired furnaces containing many catalyst-containing tubes. There are several requirements in reforming that might normally be considered mutually incompatible ... 

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