Oil firing

Hokkaido University Hokkaido MDX-1 5 2.5 oil-fired open cycle test facihty... 

Similar to oil-fired plants, either low NO burners, SCR, or SNCR can be appHed for NO control at PC-fired plants. Likewise, fabric filter baghouses or electrostatic precipitators can be used to capture flyash (see Airpollution controlmethods). The collection and removal of significant levels of bottom ash, unbumed matter that drops to the bottom of the furnace, is a unique challenge associated with coal-fired faciUties. Once removed, significant levels of both bottom ash and flyash may require transport for landfilling. Some beneficial reuses of this ash have been identified, such as in the manufacture of Pordand cement. 

A notable difference between the newer large machines and the somewhat smaller units is the use of multiple, reverse-flow can combustors configured annulady. Because the individual cans are relatively small, they reportedly lend themselves well to laboratory experimentation with various fuel types, including reduced-heat value synfuels (see Fuels, synthetic). A dry, low NO version of the can combustors has been developed for both gas and hquid fuel firing. NO emissions can reportedly be held below 25 ppm when firing gas fuel. By employing water injection, NO emissions can be held below 60 ppm for oil-fired units. 

The simplest unit employing vacuum fractionation is that designed by Canadian Badger for Dominion Tar and Chemical Company (now Rttgers VFT Inc.) at Hamilton, Ontario (13). In this plant, the tar is dehydrated in the usual manner by heat exchange and injection into a dehydrator. The dry tar is then heated under pressure in an oil-fired hehcal-tube heater and injected directly into the vacuum fractionating column from which a benzole fraction, overhead fraction, various oil fractions as side streams, and a pitch base product are taken. Some alterations were made to the plant in 1991, which allows some pitch properties to be controlled because pitch is the only product the distillate oils are used as fuel. 

In extremely cold environments, engines can quickly become difficult, sometimes nearly impossible, to start. If ordinary gasoline- or diesel-oil-fired heaters are used, the coolant circulation pump, air fan, etc, must be powered from the vehicle s batteries, thus curtailing the time the system can be used, especially at very low temperatures when it is needed the most. By adding PbTe thermoelectrics to such heater systems, about 2% of their thermal output can be turned into electricity to mn the heater s electronics, fuel pump, combustion fan, and coolant circulation pump, with stiH sufficient power left over to keep the vehicle s battery fliUy charged. The market for such units is in the hundreds of thousands if manufacturing costs can be reduced. 

S. M. DeCorso, R. A. Symonds, and G. Vermes, Crude Oil Firing in the Utilif Gas Turbine, ASME 71-WA/GT-ll, American Society of Mechanical Engineers, New York, 1971. 

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. 

Auxiliary Equipment On direct-heat rotating equipment, a combustion chamber is required for high temperatures and finned steam coils are used for low temperatures. If contamination of the produc t with combustion gases is undesirable on direct-heat units, indirect gas- or oil-fired air heaters may be employed to achieve temperatures in excess of available steam. 

Unless material characteristics hmit the gas temperature, the inlet temperature is usually fixed by the heating medium employed i.e., 400 to 450 K for steam or 800 to 1100 K for gas- and oil-fired burners. The proper exit-gas temperature is largely an economic function. Its value may be determined as follows ... 

Mercury from cinnabar ore 225 tons ore/day (95% recovery) (2) 18,0 ft. diam, 8 hearth furnaces Furnaces fired on hearths 3 to 7, inclusive retention time of 1,0 hr, furnaces are oil-fired with low-pressure atomizing air burners all air, both primary and secondary, introduced through the burners draft control by Monel cold-gas fans downstream from mercury condensers. 

NO -laden fumes are preheated by effluent from the catalyst vessel in the feed/effluent heat exchanger and then heated by a gas- or oil-fired heater to over 600° F. A controlled quantity of ammonia is injected into the gas stream before it is passed through a metal oxide, zeolite, or promoted zeolite catalyst bed. The NO is reduced to nitrogen and water in the presence or ammonia in accordance with the following exothermic reactions ... 

Oil-fired 65 5 80 Oils produced from solid wastes possibly required to be blended to reduce corrosiveness... 

FIG. 27-29 Circular register liiirncr with water-cooled throat for oil firing. (Bahcock i- Vld/eur Co.)... 

Fuel Characteristics Fuel choice has a major impact on boiler design and sizing. Because of the heat transfer resistance offered by ash deposits in the furnace chamber in a coal-fired boiler, the mean absorbed heat flux is lower than in gas- or oil-fired boilers, so a greater surface area must be provided. Figure 27-42 shows a size comparison between a coal-fired and an oil-fired boiler for the same duty. 

FIG. 27-42 Comp arison of the sizes and shapes of typical 500-MWg coal- and oil-fired boilers. Adapted with permission fixjm Lawn, Principles of Combustion Engineering for Boilers, Academic Press, London, 1987.)... 

Limits on flue-gas velocities for gas- or oil-fired industrial boilers... 

There are a number or types of special brick obtainable from individual producers. High-burned kaolin refractories are particularly valuable under conditions of severe temperature and heavy load or severe spalling conditions, as in the case of high-temperature oil-fired boiler settings or piers under enamehng furnaces. Another brick for the same uses is a high-fired brick of Missouri aluminous clay. 

U.S. Interagency Team Proposes Program to Quantify Effects of Kuwait Oil Fires," /. Air Waste Management Assoc. 41,(6), June 1991. 

The NOx water injeetion rate for oil firing versus gas turbine eompressor inlet temperature... 

High-temperature corrosion is induced by accelerated reaction rates inherent in any temperature reaction. One phenomenon that occurs frequently in heavy oil-firing boilers is layers of different types of corrosion on one metal surface. 

Harada, Y. High Temperature Corrosion in Heavy Oil Firing Boilers, Proc. Fifth Int. Cong, on Metallic Corrosion (Houston, TX National Association of Corrosion Engineers, 1974). 

Both gas and oil-fired heating systems consist of several subsystems. The oil burner pump draws fuel... 

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