50mw grade ultra-high temperature back pressure recovery type exhaust steam regulation bypass system and its control method

Abstract

The invention discloses a 50MW grade ultra-high-temperature back pressure steam turbine recovery type steam exhaust adjustment bypass system. The system comprises a 50MW grade ultra-high-temperature back pressure steam turbine and a main atmospheric steam exhaust pipeline; a recovery type adjustment bypass system is further arranged on the part, between a steam exhaust valve and a safety valve, ofthe main atmospheric steam exhaust pipeline and comprises a steam exhaust adjustment bypass pipeline, an adjustment bypass adjusting valve, an atmospheric type flash vessel, a drainage pump and a deaerator; one end of the steam exhaust adjustment bypass pipeline is connected to the main atmospheric steam exhaust pipeline, and the other end of the steam exhaust adjustment bypass pipeline is connected to the atmospheric type flash vessel; the adjustment bypass adjusting valve is arranged on the adjustment bypass pipeline; the atmospheric type flash vessel is connected to the deaerator through adrainage pipeline; and the drainage pump is arranged on the drainage pipeline. The system has the advantage that the 50MW grade ultra-high-temperature back pressure steam turbine can be protected atstarting stage of the 50MW grade ultra-high-temperature back pressure steam turbine and under the working condition of the maximum heating load. Meanwhile, the invention further discloses a specific control method for the system.

Description

technical field [0001] The patent of the invention relates to the field of thermal engine and thermal control automation in power plants, and in particular to a recovery type exhaust steam regulation bypass system and its control method for a 50MW ultra-high temperature back pressure machine. Background technique [0002] As a commonly used model for combined heat and power generation, the back pressure heating unit has the advantages of high comprehensive energy utilization efficiency, energy saving and environmental protection, and can well meet the needs of centralized heating in cities and industrial parks. The "Cogeneration Management Measures" jointly issued by the National Development and Reform Commission and other departments also encourages the development of back-pressure heating units, so how to ensure the safe and economical operation of back-pressure heating units is of great significance. [0003] The start-up process of the back pressure machine is quite diff...

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Problems solved by technology

[0003] The start-up process of the back pressure machine is quite different from the start-up process of the pure condensing unit. When the pure condensing unit is started, the low-pressure cylinder exhaust steam is directly discharged into the condenser, there is no environmental influence factor such as noise, and the working medium is also well recovered; However, the back pressure machine does not have a condenser, and the parameters of the exhaust steam at start-up cannot meet the requirements of the external heating steam parameters. During the start-up, the back-pressure unit needs to exhaust steam to the air, which is not only noisy, but also the exhaust steam cannot be effectively recovered.

[0004] In addition, for large-scale back pressure machines with ultra-high temperature parameters of 50MW level, due to the increase of the steam intake and temperature of the steam turbine, the exhaust steam volume increases, the exhaust steam temperature increases, and the start-up time becomes longer during the start-up period of the unit, resulting in 50MW level The size of the main exhaust pipe of the ultra-high temperature back pressure machine is also much larger than the size of the exhaust pipe of the back pressure machine with the conventional inlet steam temperature, and the waste of working fluid is serious; It is difficult to accurately control the back pressure of the pipeline, and the unit has certain safety problems; when the exhaust steam is overpressured, the back pressure is relatively unstable, and the safety valve often operates, which affects external heating

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