Measures to prevent the bending and burning of the

2022-09-21
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Measures to prevent the bending of the main shaft and the burning of the bearing bush of the steam turbine

in order to prevent the bending of the rotor of the steam turbine and the burning of the bearing bush, the relevant provisions of the technical measures to prevent the bending accident of the main shaft of the 200000 kw unit [(85) Dian Sheng Huo Zi No. 87, Ji Huo Zi No. 64] issued by the former Ministry of water resources and electric power should be carefully implemented, and the following key requirements should be put forward:

1 prevent the bending of the main shaft of the steam turbine

1.1 materials that should be available and familiar with

1.1.1 the maximum shaking value (double amplitude) of the original bending of the rotor installation, the axial position of the maximum bending point and the position in the circumferential direction

1.1.2 the installation position of the measuring point of the main shaft bending meter, the original shaking value (double amplitude) of the rotor, and the position of the highest point in the circumferential direction

1.1.3 Bode diagram and measured critical speed of shafting during normal startup of unit

1.1.4 under normal conditions, the turning current and current swing value, as well as the corresponding oil temperature and jacking oil pressure

1.1.5 idling curve during normal shutdown, and the opening time of corresponding vacuum and jacking oil pump. The idling curve of vacuum shutdown process is destroyed in an emergency

1.1.6 the decline curve of the main metal temperature of the cylinder under the normal state of the unit after stopping the teaching mechanics center machine

1.1.7 axial clearance and radial clearance of flow passage part

1.1.8 it shall have typical startup curve and shutdown curve of the unit under various states, and shall be fully included in the operation regulations

1.1.9 record the main parameters and states that are much higher than those in other European countries during the whole process of unit startup and shutdown. After shutdown, regularly record important parameters such as cylinder metal temperature, shaft bending, turning current, cylinder expansion, differential expansion, etc. until the next hot start of the unit or the cylinder metal temperature is lower than 150 ℃

1.1.10 for the transformation of the system and the important operation or test that has not been specified in the operation regulations, the safety technical measures must be formulated in advance and implemented after being approved by the superior competent department

1.2 the turbine must meet the following conditions before starting, otherwise it is forbidden to start

1.2.1 the main shaft shaking, shaft string, differential expansion, low oil pressure and zhenanyang is a big city, etc. the meter display is correct, and the protection is normally put into operation

1.2.2 the shaking value of the main shaft shall not exceed the specified value of the manufacturer or ± 0.02mm of the original value

1.2.3 the temperature difference between the upper and lower cylinders of the high-pressure outer cylinder shall not exceed 50 ℃, and the temperature difference between the upper and lower cylinders of the high-pressure inner cylinder shall not exceed 35 ℃

1.2.4 the main steam temperature must be 50 ℃ higher than the maximum metal temperature of the cylinder, but not higher than the rated steam temperature. The superheat of steam shall not be less than 50 ℃

1.3 operation during unit startup and shutdown 6 Press the "start" key to take measures

1.3.1 the continuous turning time before the start of the unit shall comply with the relevant regulations of the manufacturer, which shall not be less than 2 ~ 4h, and not less than 4H for hot start. If the barring is interrupted, the time shall be counted again

1.3.2 during the starting process of the unit, the shutdown due to abnormal vibration must return to the turning state, and comprehensive inspection, careful analysis and identification of the causes should be carried out. When the unit has met the starting conditions, it can be started again after continuous turning for not less than 4H. Blind starting is strictly prohibited

1.3.3 put the turning gear into operation immediately after shutdown. When the turning current is larger than the normal value, swings or has abnormal sound, find out the cause and deal with it in time. When the steam seal friction is serious, place the high point of the rotor at the highest position, close the cylinder drainage, maintain the temperature difference between the upper and lower cylinders, monitor the rotor curvature, and manually crank 180 ° after confirming that the rotor curvature is normal. When the turning gear does not move, it is strictly prohibited to use the crane to forcibly turn the gear

1.3.4 when the barring is temporarily stopped due to barring failure after shutdown, the change of rotor curvature should be monitored. When the curvature is large, manual barring should be used for 180 °, and continuous barring should be put into operation in time after the barring is normal

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