The thermal efficiency of oil and gas heating boiler
For oil or gas heating boiler, to save fuel and improve the thermal efficiency of the boiler, the common measures are as follows:
1. Adopt flue gas waste heat recovery technology to reduce smoke emission loss.
The main factor affecting the heat loss of smoke exhaust is smoke exhaust temperature. The higher the exhaust temperature, the greater the heat loss.
At present, most newly built boilers are equipped with flue gas waste heat recovery device, such as economizer, semi-condensing or fully condensing flue gas waste heat recovery device, these measures can effectively reduce the smoke exhaust temperature, improve the thermal efficiency of the boiler.
2. If the excess air coefficient is too high, it is equivalent to breathing in the extra cold air into the furnace. This part of the extra cold air does not participate in the combustion, but is discharged in vain after heating, and the heat loss of exhaust smoke increases.
If the cold air entering the furnace continues to increase, beyond a certain limit, the temperature in the furnace will decrease and incomplete combustion loss will increase.
When the excess air coefficient is too low, the fuel cannot be completely burned due to insufficient oxygen, resulting in the increase of incomplete combustion loss. The long-term serious incomplete combustion will lead to the boiler heated area carbon, affect the heat exchange efficiency, smoke loss continues to increase.
Therefore, reasonable control of air-fuel ratio, as far as possible to reduce the exhaust smoke heat loss q2 and incomplete combustion loss q3, is another key point to improve the thermal efficiency of the boiler.
3, strict control of boiler water quality, scientific control of scale.
Boiler water will contain a variety of impurities and calcium, magnesium and other scaling substances, the boiler will inevitably scale. The thermal conductivity of scale is very low, so once scale forms on the heating surface, due to the increase in thermal resistance, the boiler exhaust temperature will rise, exhaust heat loss will increase.
Test data show that the scale of 1mm on the heating surface of the boiler will increase the heat loss of exhaust smoke by about 2% ~ 4%. The thicker the scale on the heating surface of the boiler, the greater the thermal resistance, and the more the thermal efficiency of the boiler will decrease.
Boiler scaling not only reduces the thermal efficiency of the boiler, but also makes the heating surface of the boiler rise high, causing damage to the heating surface and even causing boiler explosion accident.
Therefore, the use of high-quality soft water treatment device, in strict accordance with the flow of boiler water softening treatment device, control the boiler water quality, can delay the formation of scale.
At the same time, real-time control of boiler scale, grasp the status of boiler scale, scale cleaning when necessary is also very important.
4. Strengthen insulation, prevent leakage and reduce heat loss.
Since the temperature of boiler body and steam heating pipe system is always higher than the air temperature in boiler room, part of the heat will be dissipated to the surrounding air in the form of radiation and convection, which becomes the heat loss of boiler. Therefore, when the insulation layer of boiler and heat pipe system is damaged or leakage is found, it should be repaired in time to reduce heat loss.
The above is my personal opinion on "how to improve the thermal efficiency of oil or gas heating boiler", which I hope will be useful to you.
