The control of stable first and second steam temperatures in biomass boiler operation is of great significance to the safe and economic operation of the unit. When the steam temperature is too high, it will cause the strength of some metals such as superheater, reheater, steam pipe and steam turbine cylinder and rotor to decrease, resulting in shortened service life of the equipment.
When the temperature is severely overheated, the heated surface tube will also be damaged. If the steam temperature is too low, the thermal cycle efficiency will be affected, and the steam humidity at the turbine blade will be too large. In severe cases, water hammer may occur, causing blade breakage damage.
If the steam temperature rises and falls sharply, in addition to the large thermal stress on the welded joints and joints of the biomass-fired boiler, the relative displacement between the cylinder and the rotor of the steam turbine will increase, that is, the expansion difference will increase. Even the dynamic friction between the impeller and the diaphragm occurs, causing severe vibration.
In addition, the deviation of the steam temperature on both sides of the steam turbine is too large, which will cause uneven heating on both sides of the steam turbine and uneven thermal expansion. Therefore, the steam temperature should be closely monitored, analyzed and adjusted during biomass boiler operation, and the steam temperature stability should be controlled by the most reasonable method.