How to adjust the superheated steam temperature and reheated steam temperature of boiler? What are the principles and methods?

The adjustment methods of steam temperature can be summarized into two categories: flue gas side adjustment and steam side adjustment. The so-called steam side adjustment refers to adjusting the steam temperature by changing the enthalpy of steam (such as water spray desuperheater); The adjustment of flue gas side is to adjust the temperature of superheated steam (such as flue gas baffle) by changing the distribution ratio of heat absorption between radiation heating surface and convection heating surface in boiler (such as swinging burner and flue gas recirculation) or changing the amount of flue gas flowing through superheater. 1. superheated steam temperature adjustment at present, the superheated steam temperature adjustment of drum boiler is mainly based on water spray desuperheating, and large-capacity boilers are usually equipped with desuperheaters with more than two poles. The once-through boiler is mainly adjusted by the ratio of fuel quantity to water supply quantity, maintaining the intermediate point temperature, and spraying water to cool down for correction. Guidance: the steam temperature adjustment of drum boiler is based on one-time water spray desuperheating, and its water spray amount depends on the steam temperature in front of desuperheater, so that the screen wall temperature does not exceed the allowable value; Secondary spray cooling is used as fine adjustment to ensure the stability of superheated steam temperature. The steam temperature of once-through boiler is mainly adjusted roughly to ensure a reasonable ratio of fuel to feed water. On this basis, the superheated steam temperature is finally adjusted finely by desuperheating water. 2. Reheat steam temperature adjustment The commonly used methods of reheat steam temperature adjustment include flue gas baffle, flue gas recirculation, swinging burner and emergency water spraying to cool down. Guidance: Try not to use emergency water spray during operation, which will affect the thermal efficiency of the unit. As far as possible, flue gas side adjustment is the main means to adjust the reheat steam temperature. It should be noted that at low load, water should be sprayed as little as possible or not to reduce the temperature, and the combustion mode should be adjusted in combination with flue gas side adjustment to control the steam temperature. If water spray is used to cool down at low load, improper use will easily lead to low steam temperature, which is not conducive to safety. When the automatic steam temperature regulator is put into use, the steam temperature should be kept stable.