The so-called low calorific value gas refers to gaseous fuel with low calorific value obtained from the gasification of solid fuels such as coal or coke. The fuel staged combustion technology of this burner is also called three-stage combustion technology or reburning technology. Air and fuel are fed into the furnace in stages to form an initial combustion zone, a reburning zone and a burnout zone. During flue gas recirculation, part of the low-temperature flue gas is directly sent to the combustion area, or mixed with primary air or secondary air and then sent to the combustion area, which not only reduces the combustion temperature, but also reduces the oxygen concentration, thereby reducing the nitrogen oxides. Emission concentration. So what are the other characteristics of low calorific value gas burners? The editor will introduce it below.

Features of low calorific value gas burner:

1. Gas contains few combustible components, low calorific value, high ignition temperature, slow flame propagation speed, and difficulty in ignition and stable combustion;

2. The gas pressure is low and the fluctuation range is large. It is easy to backfire when the pressure is too low and the speed is too slow;

3. Low calorific value gas is mostly the exhaust gas from chemical production lines. Multiple production lines need to be aggregated and comprehensively utilized, and the flow rate of gas changes greatly;

4. The operation of the chemical process has a great impact on the composition and calorific value of the exhaust gas. The combustion process of the exhaust gas, such as the air distribution coefficient, needs to be matched and adjusted in time, otherwise it is easy to flameout.

5. According to combustion theory, in order to ensure stable combustion of low calorific value gas, the main combustion stabilizing measures include optimizing ignition conditions, increasing flame temperature, and optimizing combustion field distribution.

6. Optimize fire conditions. Low calorific value gas fuel has a high ignition limit, is more difficult to ignite, and has a lower combustion temperature. To this end, it is necessary to increase the calorific value of gas and reduce the lower ignition limit of fuel.

7. Increase the flame temperature. The increase in combustion temperature can enhance the radiation heat transfer in the furnace and improve the combustion conditions in the furnace. The actual flame temperature is related to the device type, combustion efficiency, fuel type, air/gas preheating temperature, etc.

8. Optimize combustion field distribution. The distribution of the combustion field includes the distribution of gas, space and flue gas in the combustion space. The optimized distribution of the combustion field, especially the temperature field, comes from the heating of fresh gas and air by high-temperature flue gas, which in turn promotes the air and flue gas to heat up to Ignition temperature.

The above is the editor’s summary of the characteristics of low calorific value gas burners. The introduction of its characteristics is because the performance of the burner plays a major role in the reliability and economy of low calorific value gas combustion equipment. Starting from the generation mechanism of nitrogen oxides, through specially designed burner structures and by changing the air-to-coal ratio of industrial burners, the aforementioned air classification, fuel classification and flue gas recirculation can be used to reduce the concentration of nitrogen oxides in low-nitrogen combustion. Technology is used in burners to reduce the concentration of ignition oxygen as much as possible and appropriately reduce the temperature of the ignition zone to minimize the generation of nitrogen oxides. This is the main design concept of low-nitrogen oxide burners at present. Another commonly used combustion technology in low-NOx burners is low-NOx swirl combustion technology.