Combustion method of burner for hot blast furnace
Combustion method of burner for hot blast furnace
The combustion of gas fuel in the burner of the hot blast stove is controlled by both physical processes and the mixing process of gas and air. Depending on the mixing of the two gases, it is usually divided into long-flame combustion, no-flame combustion, and short-flame combustion. To complete the combustion of a certain amount of gas, the combustion space required for long-flame combustion is large, while the space required for short-flame combustion is small.
This means that under the same adiabatic conditions, the combustion temperature of short flames will be higher. The amount of air required for complete combustion of a certain amount of gas is defined as the theoretical air amount. The actual air volume is always greater than the theoretical air volume, and the ratio is the excess air coefficient. In the three combustion processes, the excess air coefficient of premixed combustion of the hot blast stove burner must be very small, while the excess air coefficient of diffusion combustion of the hot blast stove burner must be large. If the excess air is heated to the combustion temperature, it will consume heat, which will inevitably lead to a decrease in the overall combustion temperature. Therefore, the combustion temperature of premixed combustion is higher than that of diffusion combustion.
It can be seen that the closer the combustion mode of the hot-blast furnace burner is to premixed combustion, the better it is; this is also the reason why it is difficult to achieve high air temperatures with sleeve burners, rectangular burners, rotating multi-nozzle stratified mixing burners, and other similar burners.