Protection for preventing heat-engine plant reheater cold segment pipe from generating water impact

Abstract

The invention relates to a protection technique used for preventing water shock from happening in a cold reheat pipe of a reheater in a heat-engine plant. The protection of the invention uses the basic control functions of a DCS system to realize the purpose of protecting the cold reheat pipe of the heat-engine plant and preventing water shock from happening in the cold reheat pipe of the reheater on the bases that the DCS control system, a bypass control system and a reheater cooling control system can all work normally and not only the requirements of relevant document of the power system can be met but also the conventional designed functions are not changed. Simultaneously, as a small quantity of water-spraying of the reheater is allowed to be input during the start of the unit, the temperature of reheated steam can be easily controlled, thus achieving the purpose of shortening the start time of the unit, saving energy and improving the economic efficiency of the unit. The protection technique can be widely applied to the thermal generator set with one-time intermediate reheating.

Description

1. Technical field [0001] Under the condition of ensuring the safety of the unit, a set of thermal power plant reheater is designed based on the principle of "simple, practical and reliable" by using the existing reheater desuperheating water system, bypass control system and DCS control logic function of the unit A protection and control scheme for pipeline water impact in the cold section, which can be widely used in thermal power plants with primary intermediate reheating units. 2. Background technology [0002] At present, the primary intermediate reheating units of large and medium-sized thermal power plants are not designed to protect the cold section of the reheater. However, during the start-up process of some domestic power plants, reheating occurs due to abnormalities in related field equipment or misoperation by operators. Accidents caused by water impact on the pipeline in the cold section of the heater, and each accident is related to the opening of the high sid...

AI Technical Summary

Problems solved by technology

[0004] However, during the actual start-up process of the unit, especially the unit started by the medium-pressure cylinder, the temperature and pressure of the reheat steam are high, and the reheater flue baffle or swing nozzle is used to control the temperature of the reheat steam. The unit basically cannot meet the requirements during the start-up period of the unit, and it is easy to cause the reheat steam to overheat. Therefore, the operating personnel generally use the reheater accident spray water to control the temperature of the reheat steam to meet the start-up requirements of the unit. Once the unit is ready to be connected to the grid, the emergency spray valve of the reheater will be closed

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