Hearth negative pressure control method and system for coal-fired generating unit draught fan driven by small steam turbine

Abstract

The invention relates to a hearth negative pressure control method and a hearth negative pressure control system for a million-kilowatt coal-fired generating unit draught fan driven by a small steam turbine. Hearth negative pressure is adjusted through the force of the draught fan and can be controlled by changing the opening of a guide blade of the fan and the rotating speed of the small steam turbine for driving the draught fan, the automatic control process is finished through a control circuit, and the control circuit measures negative pressure in a hearth in real time, compares the measured negative pressure with a set value, is adjusted through a program proportional integral link and the like in the control circuit, and sends a signal to control the opening of the guide blade of the draught fan or the rotating speed of the small steam turbine so as to keep the hearth negative pressure stable. By the method and the system, technical guarantee is provided for driving the draught fan by using the small steam turbine under the condition of ensuring that the hearth negative pressure requirement is met and the unit normal variable load adjustment and unit failure working conditions, standard coal consumption is low when the small steam turbine drives the draught fan to supply power, auxiliary power and coal consumption for power supply are obviously reduced, more electricity is sold to a power grid, economic benefits are obvious, and obvious energy-saving benefits and technical popularization value are achieved.

Description

technical field [0001] The invention relates to a furnace negative pressure automatic control method driven by a small steam turbine of an induced draft fan of a coal-fired generating set with a million kilowatts, and also relates to a control system used in the method. Background technique [0002] At present, the conventional design of induced draft fans of domestic coal-fired generator sets is driven by electric motors. With the increase of the capacity of generator sets, it becomes more and more difficult to design power consumption when electric motors are used, and it will cause a large increase in investment costs. . If the design of the induced draft fan and the desulfurization booster fan is optimized, and the scheme of combining the booster fan and the induced draft fan is adopted, the maximum working condition electric power of the induced draft fan will be close to 11,000 kilowatts. Due to the high power of the motor, it is very difficult to design power for the ...

AI Technical Summary

Problems solved by technology

[0002] At present, the conventional design of induced draft fans of domestic coal-fired generator sets is driven by electric motors. With the increase of the capacity of generator sets, it becomes more and more difficult to design power consumption when electric motors are used, and it will cause a large increase in investment costs.

If the design of the induced draft fan and the desulfurization booster fan is optimized, and the scheme of combining the booster fan and the induced draft fan is adopted, the maximum working condition electric power of the induced draft fan will be close to 11,000 kilowatts. Due to the high power of the motor, it is very difficult to design power for the plant. Excessive start-up current will also cause the voltage of the power bus of the factory 6KV module to be too low, which will affect the safety of other operating equipment

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