Feedwater regulating system used for boiler in heat-engine plant

Abstract

The invention discloses a feedwater regulating system used for a boiler in a heat-engine plant. The boiler is used for supplying steam to a steam turbine. The feedwater regulating system comprises a first water-feeding pump, a first water pump motor and a first frequency converter. A water outlet of the first water-feeding pump is communicated with a water inlet of the boiler, and the first water-feeding pump is used for pumping water into the boiler. The first water pump motor is connected with the first water-feeding pump through a first hydraulic coupler to drive the first water-feeding pump to run. The first frequency converter is disposed between a power supply and the first water pump motor, and the first frequency converter is used for making the frequency of the power supply fluctuate from 0 to 50 Hz to regulate the rotational speed of the first water-feeding pump so as to control the quantity of feedwater of the first water-feeding pump. According to the feedwater regulating system, the rotational speed of the water-feeding pump can be regulated through regulating the frequency of the power supply, the efficiency of speed regulation is higher compared with the prior art that speed regulation is carried out through changing the opening of a scoop tube by a conventional hydraulic coupler, the energy consumption is low, and the effect of energy conservation is distinct.

Description

technical field [0001] The invention relates to the field of feed water for boilers in thermal power plants. More specifically, the present invention relates to a feedwater conditioning system for boilers in thermal power plants. Background technique [0002] The 2×330MW unit of Datang Guiguan Heshan Power Generation Co., Ltd. was put into operation in 2004. The boiler is a 1004t / h boiler manufactured by Dongfang Boiler (Group) Co., Ltd. The steam turbine and generator are manufactured by Beijing Beizhong Steam Turbine Motor Co., Ltd. The unit has the characteristics of quick start / stop and strong peak regulation capability, and its designed minimum stable load is 40% of the rated load. The electric feed water pump of each unit is 2 for use and 1 for backup. During normal operation, the water supply system is automatically controlled by DCS (distributed control system). When it is greater than 30%, the DCS adopts the three-impulse control mode of the main steam drum water ...

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Problems solved by technology

[0003] Since it was put into production, the feedwater pump motor of this unit has been in the state of power frequency operation. During the start / stop stage and load changing stage of the unit, the output can only be adjusted by adjusting the opening of the hydraulic coupler spoon tube. Operation in the economic zone, so it is necessary to carry out frequency conversion transformation for this feed water pump motor

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