The method to prevent tempering is based on the premise of reducing flame propagation speed, increasing outlet velocity of gas-air mixture and ensuring uniform velocity field.The anti-tempering measures adopted in installation and production mainly include the following aspects:
1. According to the nature of the gas, the combustion method should be selected reasonably. For the gas with fast flame propagation speed (gas with high hydrogen content), atmospheric combustion and non-flame combustion should not be adopted.
2. When using dirty gas, a purification device (such as a filter, etc.) should be set up. When the purification device still fails to prevent scaling of gas nozzle and mixing pipe, the combustion device should be descaled, or a structure that is easy to remove dirt should be adopted, and the operation system of regular cleaning should be stipulated.
When using water-containing gas, there should be a water separator to avoid freezing of gas nozzle and mixing pipe in cold weather.
When the furnace is operating under low load, part of the burner burner should be turned off to ensure that the operating burner load is not less than the permitted minimum load.
5. In the process, the minimum pressure value should be specified according to the nature of the gas and the form of the burner. When the gas pressure drops to the low limit, the operation should be stopped to ensure that the exit velocity of the gas-air mixture is not less than the flame propagation velocity.
6. According to the nature of the gas, the structure and process of the burner, if tempering occurs due to excessive burner head temperature, the burner head can be cooled to reduce the flame propagation speed.