"The fuel that consumes most in the use of boilers is fuel. To take energy-saving measures, it is necessary to start with the selection of fuel.". Under current socio-economic conditions, there are three main types of boiler fuels, namely, solid fuel, gas fuel, and liquid fuel. These three different fuels generate different amounts of heat and pose different levels of harm to the environment. On the whole, gaseous fuels have great advantages in terms of heating quality and environmental protection, and should be given priority when selecting fuels. However, in some boiler heating systems, due to the impact of production processes and fuel supply capacity, the selection of gaseous fuels is still subject to certain restrictions. In the selection of fuel oil, due to its high cost, it is often more expensive to choose this fuel for boiler heating. Currently, it is feasible to use briquette and vaporize it before using it. This way, there is less residue after combustion, and the amount of exhaust gas emitted during excessive combustion is also small. Moreover, the calorific value of combustion of briquette after vaporization is relatively high, so it is more cost-effective to use it in boiler heating.

In terms of combustion mode, the combustion modes of different forms of fuel are different: gaseous fuels mainly include flame combustion and flameless combustion, which is also known as gas phase combustion. The flame is long and has a clear contour. The speed of flame combustion is greatly related to the mixing speed of air. Flameless combustion refers to solid phase combustion, which has a faster combustion speed and a higher combustion temperature. The disadvantage is that the combustion capacity is relatively small. There are also two combustion forms of liquid fuels, namely, high-pressure atomization and low-pressure atomization. High pressure atomization is more suitable for some larger boilers. Although it can effectively recover the residual heat from flue gas, the operating cost and energy consumption are relatively high. Low pressure atomization is mainly applicable to small and medium-sized boilers, with high energy consumption and cost. Although it is not convenient to collect flue gas, corresponding methods can still be used to collect waste heat. Among the forms of solid fuel combustion, coal gasification combustion is the best, and thin coal seams are the worst. During boiler selection, various conditions should be compared based on the actual situation to determine the appropriate fuel and combustion method.