Foster Wheeler Energy Corporation

Westinghouse Electric Corporation

Robert Lenox Criswell

Paul Vincent Guido

Morton H Binstock

Albert J Zipay

Michael C Polagye

In a fluidized boiler system, the rate of fuel flow and bed depth are simultaneously controlled in response to variations in a load demand signal representing the need for steam output from the system. When the load demand changes, the rate of fuel flow is varied accordingly to provide a change in the bed temperature to thus provide a rapid response to the change in the demand signal. At the same time, the system changes the rate of flow of limestone to the bed and the rate of removal of spent particulate material of the bed to change the bed depth to respond more slowly to the change in the demand signal. As the depth of the fluidized bed approaches a value corresponding to the demand signal, the temperature of the bed will change back toward a median value.

Fluidized bed heat exchanger with control to respond to changes in demand

A steam blending control is provided for two or more boilers in an electric power plant. To blend an oncoming boiler with an on-line boiler, the oncoming boiler is fired to a pressure ramp setpoint and outlet steam is isolated from the plant turbine and directed through position controlled bypass valve means. When steam temperature and pressure conditions are matched, the oncoming boiler isolation valve is opened and the bypass flow then existing is stored in a memory. The oncoming boiler bypass flow is cut back with total oncoming boiler steam flow controlled to the memorized flow valve as a setpoint. Flow from the on-line boiler is cut back under load control as the oncoming boiler flow to the plant turbine is increased. Deblending is implemented in a similar manner.

Multiple boiler steam blending control system for an electric power plant

A power generation system in which one or more vapor generators are provided for driving a turbine having a relatively high pressure section and at least one relatively low pressure section. A reheater is disposed between the high pressure turbine section and the low pressure turbine section and its outlet is connected to the latter section. The steam outlet of the vapor generator is connected directly to the high pressure turbine section and directly to the reheater, and the outlet of the reheater is connected directly to the low pressure turbine section and directly to the condenser.

Power generation system

There has been provided a control for regulating the pressure excursions in a furnace having forced draft and induced draft fans. A pressure detector responsive to pressure in the furnace delivers an output indicative thereof. Circuit means, responsive to the pressure detector means and a set point input, delivers a correction signal output. Fan control means coupled to the induced draft fan is responsive to a demand input signal corresponding to a desired flow rate through the furnace and is likewise responsive to the correction signal for delivering a fan control signal for regulating said induced draft fan in accordance with variations in the flow rate and pressure excursions in the furnace. An override circuit is responsive to the pressure detector and an override set point input to produce an override output for controlling the induced draft fan at a rate substantially higher than that of the correction signal. There is also provided a transfer and memory circuit responsive to combustion air flow to the furnace and a furnace trip condition such that the circuit produces a signal to modify said fan control signal in accordance with the actual air flow to the furnace and in anticipation of an inevitable furnace pressure excursion caused by said furnace trip.

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Florham Park, NJ, United States of America

Robert Lenox Criswell