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Background introduction

The gas turbine power plant adopts the STAG-109FA-SS single-shaft combined cycle unit, which is composed of a PG9351FA gas turbine, a two-cylinder dual-flow steam turbine with a D10 three-pressure reheat system, a 390H hydrogen-cooled generator, and a triple-pressure reheat but with a condenser The natural circulation waste heat boiler for deoxygenation is composed of [1]. Except that the waste heat boiler is supplied by Hangzhou Boiler, the rest are provided by Harbin Power Equipment Co., Ltd. and General Electric Company of the United States. The gas turbine, steam turbine and generator are rigidly connected in series on a long shaft, and the shaft configuration is in the form of GT (gas turbine)-ST (steam turbine)-GEN (generator).

Status of bearing operation

The gas turbine unit has been shut down for a long time after being overhauled. After the cold start-up, it was found that the temperature of the bearing bush metal of the unit 4# was high. When the unit is running at full load, real-time monitoring of 4# bearing bush, 5# bearing bush and lubricating oil inlet temperature is carried out. Through the monitoring data, it can be found that when the unit is operating at full load, the temperature measurement points of the two bushes of 4# bearing are near the high alarm value of the bearing bush temperature, while the temperature of the 5# bearing bush is basically below 100 ℃, and the bearing bush has temperature during operation. High abnormal phenomena threaten the safe and stable operation of the unit.

Bearing maintenance

After analysis, this bearing inspection includes two items. The first item is to restore the bearing orifice plate to the initial design value. The second item is to remove the 4# and 5# bearings and inspect them, and if necessary, the bearing Re-poured. After dismantling the bearing, first check the appearance of the bearing bush. It is found that there are obvious indentations in the central area of the lowermost bush of the bearing. This area is in contact with the hard steel area on the inner surface of the bearing and is the main stress area of the bush. This phenomenon can be It is inferred that the pad has received a relatively large load, and the bearing pad is likely to be deformed. In order to further verify the appeal inference, the lower half of the bearing was subjected to the step of pressing the false shaft, and the contact between the bearing bush and the rotor was checked. After pressing the false shaft, the red lead on the bearing bush was unevenly distributed. It can be judged that the bearing bush has been deformed and needs to be returned to the factory for re-pouring. After the bearing bush is poured, the bearing is reinstalled into the unit, and the bearing and rotor Find the center and restore the relative position of the bearing and the rotor to the state before repair.