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US 4,223,640 AGranted
Fuel firing
AssigneeThe Babcock & Wilcox Company
InventorsRobert S. Rochford, Robert S. Leckonby, Ronald C. Lutwen, Gerald A. Cymny
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AssigneeThe Babcock & Wilcox Company
InventorsRobert S. Rochford, Robert S. Leckonby, Ronald C. Lutwen, Gerald A. Cymny
Estimating the term…
An apparatus and method to permit the burning of high and varying moisture content fuels without requiring supplemental fuel (oil or gas) firing. The invention provides in-situ drying of the high and varying moisture content fuels by modulating the temperature of the combustion air entering the furnace (11) of the vapor generator (10). The variable flow paths taken by the air and flue gas are functions of the moisture content of the fuel being fired. The flue gas may be selectively by-passed around an economizer (20) for direct introduction into a first air heater (30). The gas is then passed through a precipitator (34) and a second air heater (40). Combustion air is passed through the second air heater (40) and may be then apportioned between the first air heater (30) and a by-pass (60) around the air heater (40) before introduction into the furnace (11).
In combination with a vapor generator having a furnace for burning fuels of varying moisture content, an apparatus for preheating air required for combustion and comprising conduit means defining an air and a flue gas flow path to and from the furnace, respectively, and economizer disposed in the gas flow path for preheating feedwater for the vapor generator, spaced first and second air heaters disposed downstream gas flow-wise of the economizer and communicating with the air and gas flow paths to heat the air through indirect heat exchange with the gas, the second air heater being disposed upstream air flow-wise and downstream gas flow-wise of the first air heater, means for regulating the air temperature including conduit means defining an air flow path by-passing the first air heater and a gas flow path by-passing the economizer, damper means for apportioning the flow of air between the first air heater and the by-pass air flow path and damper means for apportioning the flow of gas between the economizer and the by-pass gas flow path in response to changes in flue gas temperature resulting from changes in fuel moisture content.
A method for burning fuels of varying moisture content, and including a vapor generator furnace, an economizer for preheating feedwater for the vapor generator through indirect heat exhange with flue gas, spaced first and second air heaters for preheating combustion air in indirect heat exchange with flue gas, and conduit means for by-passing flue gas around the economizer and combustion air around the first air heater, which comprises the steps of:
Dependencies are inferred from the claim text.