Factors Affecting Gas Boilers Thermal Efficiency

September 23, 2020

The thermal efficiency of a boiler is the percentage of the heat available from the fuel. The heat of gas boilers to produce hot water or steam mainly comes from the heat generated by fuel combustion. However, the fuel entering the boiler cannot be completely burned and released for various reasons, and the heat released by combustion will not be effectively used for the production of steam and hot water, among which a part of the heat will be lost.

8tph gas boilers

8tph gas boilers

It is well known that the initial cost of a boiler is only a small fraction of the total boiler-related costs over its lifetime. In the life of a boiler, the main cost is the cost of fuel. Ensuring efficient operation of boilers is critical to optimizing fuel costs. The thermal efficiency of the boiler directly reflects the boiler’s performance, which is an important reference data when choosing a boiler. When the gas steam boiler is in operation, a series of chemical and physical reactions will occur in the furnace. In the process of use, hard and dense scale will be formed on the heating surface, which will directly lead to the reduction of heat exchange efficiency of the boiler.


How to Improve Gas Boilers Thermal Efficiency

  1. Reduce boiler exhaust heat loss
    • Reduce the air leakage rate of the high air preheater, especially the air leakage rate of the rotary air preheater.
    • Strictly control the boiler water quality target. When the scale content in the water cooling wall tube reaches 400mg/m, pickling shall be timely.
    • Try to burn high quality fuel with low sulfur content to reduce the air temperature at the inlet of the air preheater. In ancient times, large capacity generation boilers were all equipped with air preheaters to avoid dew on the heating surface of the cold front end of the air preheater and cause high temperature corrosion of the air preheater.
  2. Reduce heat loss due to incomplete quenching of machinery
    • According to the boiler load and time to adjust the quenching conditions, reasonable distribution of air, so that the fuel in the furnace fully extinguished.
    • Adjust the feed amount according to fuel volatilization and time, so as to maintain the optimal value of fuel amount.
  3. Reduce the heat loss of boiler, and strengthen the maintenance and overhaul of boiler pipe and body insulation layer


14MW gas fired hotwater boiler

14MW gas fired hotwater boiler

Thermal efficiency of ZOZEN gas boilers is more than 98% and NOx emissions are reduced to 30mg/Nm3; Boiler structure design is reasonable, using ZOZEN independent research and development of efficient heat transfer element threaded smoke pipe, extend the flue gas retention time in the furnace, effectively improve the thermal efficiency. Professional thermal insulation technology makes the heat generated by natural gas combustion only a small part of the dispersion to the outside air, the vast majority of the gas steam boiler absorption and utilization.

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