37. Briefly describe the impact of moisture in medium-pressure steam on compressors and the methods for dealing with it
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37. Briefly describe the impact of moisture in medium-pressure steam on compressors and the methods for dealing with it
1. It has a significant impact on the efficiency of the turbine. The normal steam flow follows the shape of the blades, and factors such as the angle of impact of the expanding gas stream are all designed in accordance with aerodynamic principles. It has the highest efficiency, but when water is present, the droplets hitting the blades have a significant impact. 2. The greater impact is an increase in axial thrust. The axial thrust of the turbine is handled by a dedicated system. Especially reaction steam turbines. In impulse turbines as well, the axial thrust increases. In severe cases, the tiles of the thrust bearing can be burned out. This thus results in static and kinetic friction.
Impact: (1) Sudden drop in steam pressure and temperature； (2) The steam flow rate fluctuates, and the steam consumption by the turbine increases ； (3) If the rotation speed decreases, increase the opening of the steam valve. (4) In severe cases, water hammer occurs, damaging the turbine. Methods: (1) Ensure stable operation of the boiler unit ； (2) Open the steam drain valve to enhance drainage, simultaneously reduce the pressure at the compressor outlet to lower the unit’s load; in severe cases, initiate an emergency shutdown.
In daily operations, the steam temperature must not drop below 180°C. If it approaches or falls below this temperature, the operators on site must drain condensate at the lowest point of the steam pipelines near the turbine, and those in charge of steam generation should make timely adjustments, such as reducing the amount of water used for cooling. If there are no significant changes in the vibration and displacement of the turbine units, they can continue to operate or run at reduced load; however, if the temperature does not return to normal after a long period of time, it is best to initiate an emergency shutdown, as water has a significant impact on the blades.