Adjustment method of flue gas temperature in power plant

This question is really difficult to answer, because most of the reasons for smoke temperature still exist in the design, so I will briefly talk about several adjustment methods in operation.

1, reduce the burning flame center. Methods: The corner-cutting boiler can be put into the lower burner and withdrawn from the upper burner, so that the flame center will be lowered in the original position, the heat absorption of the water wall will increase, the outlet temperature of the furnace will decrease, and the temperature of the tail flue will also decrease. Other types of boilers, such as W-type boilers and offset boilers, can reduce the staged air flow, so that the flame center will also be reduced. In short, reducing the flame center position can reduce the exhaust temperature.

2. In addition, the temperature of flue gas can be adjusted by periodically purging the furnace, tail flue and air preheater, which will make the heating surface clean, so that the heating surface can absorb the heat of flue gas more easily. Thereby reducing the temperature of the flue gas.

3. Even if the heat exchange element of the air preheater is cleaned during maintenance, the components of the cold end of the air preheater are usually cleaned with high-pressure water. Because the cold end temperature is very low, it is easy to condense during operation, so that sulfur dioxide and sulfur trioxide in flue gas condense and stick to the heat exchange elements at the cold end, blocking the flow surface and reducing the heat exchange coefficient. Therefore, the air preheater should be washed in time during maintenance.

4. In addition, from the aspect of coal quality, let me explain to you that low ash coal quality is more favorable to reduce the exhaust temperature, because if there is too much ash in coal, it will also affect the heat exchange between flue gas and heating surface.

5. Maintain an appropriate excess air coefficient during operation. In short, the air volume should not be too large, because too large air volume will make more heat in the furnace be taken away by the flue gas, which will increase the temperature of the flue gas, so it is necessary to ensure the proper air volume operation. In fact, it is necessary to check the sealing condition of the furnace, especially the water seal at the bottom of the furnace. The destruction of the water seal at the bottom of the furnace will make a lot of air enter from the bottom of the furnace, make the flame center of the furnace rise, and also make the exhaust temperature rise.

In short, there are still many aspects that can be adjusted in operation, just depending on the design of the boiler. If it is operation or design, first learn the principles of thermodynamics, which is the foundation. I hope the answer will help you.