Energy-saving boiler feed pump drive system for thermal power plant

Abstract

The invention provides an energy-saving boiler feed pump drive system for a thermal power plant and solves the configuration problem of the water feed pump of a current thermal power generating unit and the problem that the water feed pump is high in energy consumption. A synchronous automatic clutch is disposed between a small steam turbine and a synchronous motor. A planet gear speed regulating device is disposed between the synchronous motor and the water feed pump. The synchronous motor is connected into a plant bus through a synchronizing switch. The water feed pump can be driven by the small steam turbine or the motor, the reliability is higher than a traditional steam pump manner or electric pump manner, optimized operation according to unit back pressure conditions can be achieved, and the drive manner of the water feed pump can be switched timely to save energy. An independent steam discharge cooling system for the small steam turbine is not needed, steam discharged from the small steam turbine can be directly discharged into a mainframe steam discharge system, influence on water feed adjusting due to the fact the shaft power of the small steam turbine is affected by back pressure sudden drop caused by high back pressure and heavy winds does not need to be worried about even for direct air cooling units, and system simplification and project construction cost lowering are facilitated.

Description

technical field [0001] The invention relates to a drive system for a boiler feed water pump in a thermal power plant, in particular to an energy-saving boiler feed water pump drive system for a thermal power plant. Background technique [0002] The boiler feed water pump is the most powerful auxiliary engine in a thermal power plant. The driving mode of the feed water pump has a great influence on the grid capacity of the unit. The efficiency of the boiler feed water pump group also has a great impact on the energy consumption of the unit. At present, domestic boiler feed water pumps have small steam turbines. There are two ways of driving and motor drive, and there is also a way in foreign countries that the main steam turbine directly drives the feed water pump. The setting of the feed water pump should meet the 105-110% BMCR working condition of the unit, and the setting of the induced draft fan should meet the TB working condition. Compared with the normal operating cond...

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Problems solved by technology

[0010] When the air-cooled unit is in normal operation, the small steam turbine always keeps the steam inlet regulating valve fully open, which avoids the problem of low operating efficiency caused by the small steam inlet regulating valve opening of the small steam turbine, and the small steam turbine does not need to be equipped with a separate exhaust cooling system. The exhaust steam of the steam turbine can be directly discharged into the exhaust system of the main steam turbine. Even for the direct air-cooled unit, there is no need to worry about the high back pressure and strong wind causing the sudden drop of the back pressure to affect the shaft power of the small steam turbine and affect the water supply adjustment, and it is helpful To simplify the system and reduce the engineering cost

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