Steam turbine is a kind of turbine mechanical equipment that converts heat energy of steam into mechanical energy. In air separation plant, steam turbine is used as power source of air compressor instead of motor, which saves a lot of power consumption for air separation users, so it is widely used in air separation field.
The following is about the influence of steam temperature or pressure on the safety performance of steam turbine:
Theoretically, the higher the main steam temperature, the higher the steam turbine operation economy. However, in actual operation, due to the direct contact between the steam inlet part and high-pressure part of the steam turbine and the high-temperature steam, when the steam temperature is too high, the mechanical strength and allowable stress of the steam turbine parts will decrease due to the temperature rise, which will shorten the service life of the unit; when the main steam temperature decreases, the output power of the steam turbine will decrease correspondingly, so it is necessary to increase the steam turbine output power in order to keep the unit power unchanged In addition, if the main steam temperature is too low, it is easy to increase the moisture loss of the low-pressure stage, which will aggravate the erosion of the moving blades.
With the increase of main steam pressure, the work capacity of steam is improved. However, if the pressure is too high, the pressure difference between the inlet and outlet of the corresponding nozzle will increase, and the bending stress of the regulating stage blade will increase, which will cause damage to the blade and nozzle, increase the stress of the pressure bearing parts such as the air guide pipe, steam chamber and valve, which will threaten the safe operation of the unit; if the main steam pressure is too low, the equipment operation economy will be reduced, the available enthalpy drop of the steam turbine will be reduced, the steam consumption will be large, and the axial thrust will be increased, which will make the last stage The increase of stress on the blade leads to blade deformation.
Therefore, in the commissioning and operation of steam turbine, the temperature and pressure of steam must be kept within the design range and adjusted appropriately according to the actual situation to ensure the economic and stable operation of the air separation plant.
