Heat supply system capable of switching from extraction condensing to zero output of low-pressure cylinder and working method of heat supply system

Abstract

The invention discloses a heat supply system capable of switching from extraction condensing to low-pressure cylinder zero output and a working method of the heat supply system. A small-caliber medium-low pressure communicating pipe with a valve with an adjusting function is additionally arranged on a medium-low pressure communicating pipe of an original heat supply extraction condensing unit in parallel and serves as low-pressure cylinder steam inlet flow control before the low-pressure cylinder is cut off; temperature and pressure sensor monitoring data are newly added on an original seven-section steam extraction pipeline of the low-pressure cylinder to be connected into a unit control system, and the steam superheat degree is obtained and serves as a criterion of a low-pressure cylinder removal time point; a pipeline with a valve is additionally arranged in a pipeline between a six-section steam extraction valve of a low-pressure cylinder and the low-pressure cylinder to a condenser, when the cutting-off time point of the low-pressure cylinder arrives, the six-section steam extraction valve and the seven-section steam extraction valve are closed firstly, then a small-caliber medium-low pressure communicating pipe valve is closed, and finally the valve between the six-section steam extraction valve and the condenser is opened. Non-condensed gas in the low-pressure cylinder and hot standby steam of the communicating pipe are pumped out in advance, and the system ensures normal operation of the long movable blade of the low-pressure cylinder in a high-vacuum environment and no overtemperature of the inlet of the condenser.

Description

technical field [0001] The invention belongs to the technical field of combined heat and power generation and steam turbine operation, and specifically relates to a heating system and a working method thereof that switch from condensate extraction to low-pressure cylinder zero output. Background technique [0002] At present, in order to improve the heating and peak-shaving capacity of the heating units, the heating units in the northern region are implementing the "low-pressure cylinder zero output" transformation, that is, the steam turbine operates without the low-pressure cylinder during the heating peak-shaving period. The mainstream method is to add a small-flow steam pipeline between the medium and low-pressure cylinders to cool the blast heat in the low-pressure cylinder. The cylinder is sprayed with water for cooling. In the actual application of this method, the steam with a small flow rate does not play a cooling role, but only accelerates the flow to take away t...

AI Technical Summary

Problems solved by technology

Therefore, mainly due to the poor controllability of the large-diameter heating butterfly valve, the adjustment range of heating and extraction is narrowed.

[0004] During the process of the heating unit from condensate pumping operation to the removal of the low-pressure cylinder, it is difficult to grasp the cut-off time point under different unit load conditions. A certain opening value of the heating butterfly valve in the connecting pipe is often used as the cut-off time point of the low-pressure cylinder, resulting in low pressure Cylinder removal process is too rigid, poor flexibility

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