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Classification of common flame shapes of burners
Classification of common flame shapes of burners
1、 Active flame.
The shape, length and blackening time of the flame are relatively suitable, which is most beneficial to the quality of clinker calcination and the combustion efficiency of pulverized coal. It meets the temperature requirements of the firing zone, with low heat consumption, and the whole flame is active and powerful. This is a flame shape that operators want to get, and it is also a flame shape of normal forging.
2、 Long black flame.
This kind of flame has a long black head, low combustion efficiency and low front temperature rise. The reasons are as follows:
① Poor coal quality, low calorific value, large ash content, coarse coal particles, high humidity, etc;
② Burner failure causes poor pulverized coal air mixing effect and slow combustion speed;
③ Improper burners are used, with large external air and small internal air, improper ratio of air and coal, and insufficient air volume.
In case of such flame formation, it is necessary to timely analyze the causes, check whether the coal quality and fineness are appropriate, whether the spiral blades of the three-channel burner are damaged, and whether the air volume is sufficient. In addition, this kind of flame is also easy to occur due to improper operation, such as too fast grate bed speed, low secondary air temperature due to thin material, and long black fire head due to pulverized coal ring at kiln mouth.
3、 Slow flame (long flame).
The main reason why the flame is not concentrated in the burning zone is that the internal wind is too small to spread due to poor rotation; The external wind is too strong, the diffusion inhibition is too strong, and the flame is elongated.
However, when the front temperature is too high or the furnace brick is burnt during the operation, this flame can be adopted, which can be effectively alleviated in time; In addition, this type of flame can also be used before ignition, feeding or hanging the kiln, and can be changed when it is normal.
4、 Diffusion flame.
The shape of the flame is short and thick, belonging to the abnormal flame shape. The main reasons for its occurrence are:
① The fired belt kiln skin has a ring and a large material ball, which promotes the flame to push forward, often resulting in high front temperature, turbidity in the kiln, uneven incoming materials, large fluctuations in the host current, and increased negative pressure at the kiln end. If not handled in time, the kiln lining will be burnt out or the clinker quality will be unqualified, and the output will be reduced.
② The use of the multi-duct coal injection pipe is improper, the internal air is too large, the external air is too small, and the secondary air temperature is too high, which makes the kiln lining easy to be burned.
③ The swirl angle at the end of the internal air duct is too large, the external air cannot be controlled, and the diffusion is serious.
④ The flame hood of the multi-duct coal injection pipe is burnt out, and the closed smoke hood burns, causing flame spread.
When such flame shape is found, it is necessary to timely check whether there is ring formation in the kiln, the proportion of secondary air, whether the temperature of secondary air is too high, whether the negative pressure at the kiln end is too small, and whether the inclination of spiral blades is appropriate.
5、 Touch the kiln skin flame.
This flame moves upward, which is very easy to wash the kiln skin, shorten the service life of refractory bricks, raise the furnace temperature, and the flame shape is very abnormal, which is not conducive to heat transfer and clinker quality. The reasons are as follows:
① The position of the burner on the kiln body section is incorrect, which is above the centerline, and the red kiln is easy to occur at 6m of the kiln body.
② The shock wave generated by the nozzle being too close to the outside and the secondary air being too large will cause the flame to float upward, which is mainly due to improper operation of the cooler or serious air leakage of the kiln head cover.
When the flame of this shape is found, timely check whether the position of the burner on the cross section of the kiln shell is correct, whether the cold air volume at the kiln head is too large, and whether the secondary air volume is too large, and deal with the cause in time.Author：Ebico