Methods for improving boiler thermal efficiency

When designing low-pressure industrial boilers, manufacturers have already considered the issue of overheating efficiency, and it is unlikely to save energy by changing the equipment or flue gas. Therefore, it is best to start from the operation aspect for boiler energy conservation (the method of steam condensate recovery will not be discussed here). According to relevant data surveys, the design thermal efficiency of domestic low-pressure industrial boilers is generally between 70-90%, and the actual operating thermal efficiency is generally around 60-80%, some even below 50%. As long as small low-pressure industrial boilers are operated and maintained properly, they can fully achieve the design thermal efficiency of boiler manufacturers.

Boiler management and operation should pay attention to the following points:

1、 Monitor the exhaust temperature of the boiler. Usually, the maximum heat loss of a boiler is exhaust gas loss, so it is important to control the exhaust gas temperature of the boiler. Generally, the exhaust gas temperature of coal-fired low-pressure industrial boilers (mainly referring to boilers below 10 tons and pressure less than 1.6 MPa, the same below) is 150-180 ℃, and the exhaust gas temperature of oil-fired boilers is 210-240 ℃. Therefore, when the exhaust gas temperature is too high, it is necessary to find the cause and eliminate it in a timely manner. The reasons for the high exhaust temperature of coal-fired boilers include: 1. The negative pressure in the furnace is too high, 2. The flue gas is short circuited, 3. The smoke scale on the heating pipeline is too thick, 4. The scale inside the boiler is too thick, etc. The reasons for the high exhaust temperature of oil-fired boilers include: 1. Poor air and oil regulation, which prevents the oil from fully burning to the tail of the chimney for secondary combustion, 2. There is too much smoke and ash, which needs to be cleaned in a timely manner, 3. The flue gas is short circuited, 4. The scale is too thick, etc

2、 Control the boiler discharge rate. The discharge rate of general industrial boilers is controlled at 5-10%. On the premise of ensuring that the boiler water is qualified (mainly based on the total alkalinity and pH value), the lower the discharge rate of the boiler, the better. The principle of "frequent discharge, less discharge, and uniform discharge" should be adhered to for discharge.

3、 Maintain the furnace walls and insulation layer of the boiler. The heat dissipation loss of the boiler is also a relatively large heat loss. Currently, boiler manufacturers have considered it thoroughly in their manufacturing and design, so there is no need for us to change it. We just need to maintain it well. The temperature of the outer surface of a general boiler does not exceed 50 ℃. If it is too high, the cause should be identified and eliminated in a timely manner. The insulation layer of the boiler should be kept dry frequently. For coal-fired boilers, long-term positive pressure operation is not allowed, otherwise it is easy to damage the furnace wall and coal gate.

4、 Adjust the ratio of fuel to air volume to ensure that the fuel is fully burned as much as possible. Generally, small boilers do not have instruments such as air volume testing, so they can only be adjusted based on experience. For oil-fired boilers, during normal combustion, the flame is yellow white, not harsh, stable, and there is no visible smoke in the chimney; For coal-fired boilers, the flame is light yellow during normal combustion, there is no visible smoke in the chimney, the coal slag is basically burned, and the coal particles are as uniform as possible.

5、 There should be comprehensive boiler water treatment. Perfect boiler water treatment and water quality testing can maximize the prevention of boiler scaling and correct guidance for pollution discharge, which many small boilers have not achieved and enterprises usually do not pay attention to.

The above is the answer to this question from Jiangsu Sifang Clean Energy Equipment Manufacturing. If you have any doubts about other boiler related issues, please consult Jiangsu Sifang Clean Energy Equipment Manufacturing online customer service or call 0516-85532690. Jiangsu Sifang Clean Energy Equipment Manufacturing professional technical personnel will promptly answer your questions.