The combustion process of any fuel includes two stages of "fire" and "burning". Only when the fuel reaches the ignition temperature can the combustion be stabilized. When the gaseous fuel is mixed with air, the gas fuel section accounts for a certain percentage of the volume of the mixed gas in order to be ignited. This category is called the ignition concentration range or the fire concentration limit. It is related to the oxidation reaction rate of C, the diffusion rate of air and combustion products. Generally, gaseous fuels are burned by long flame combustion, short flame combustion, and flameless combustion. Long-flame combustion is also called diffusion-type combustion. The gas is completely out of air in the burner, and after being sprayed, it is mixed with air to be burned, and the flame is long. Short-flame combustion means that the gas is pre-supported and partially mixed in the burner, partially burned after being sprayed, and the other part is mixed with air and continues to burn, and the flame is short. Flameless combustion means that the gas and air are completely mixed before or during the burner. After burning or after the burner, the flame is almost invisible due to rapid combustion.