What factors affect the flame length of a rotary kiln?

The influence of the gas velocity in the rotary kiln on the flame length is that the faster the flow rate, the longer the flame, and the gas flow rate is affected by the primary wind speed and the exhaust air at the end of the rotary kiln. On the one hand, the increase of primary wind speed can increase the effective range of pulverized coal and lengthen the flame; On the other hand, it makes the wind and coal mix evenly, so that the combustion speed is fast and the flame is short, which are two opposite effects. At the same time, in order to prevent "tempering", the ejection velocity should be greater than the flame diffusion velocity.

The injection speed is related to the diameter of the rotary kiln, the large diameter of the rotary kiln requires a higher injection speed, and the smaller kiln diameter injection speed takes a small value, so as to create good conditions for the heat exchange between the flame and the material. The increase of the exhaust air at the tail of the rotary kiln increases the negative pressure at the tail of the rotary kiln, and the increase of the secondary air increases the gas flow rate outside the flame, so that the flame is elongated. The influence of pulverized coal combustion speed on the flame length of rotary kiln The pulverized coal combustion speed accelerates and shortens the flame length, and the factors affecting the combustion speed are as follows:

Fineness of pulverized coal: the finer the fineness of pulverized coal, the faster the combustion speed, the finer the pulverized coal, the larger the surface area of pulverized coal, and the increase in the contact area between coal and oxygen in the air, so the combustion rate is accelerated. Secondary air temperature:

The temperature increases, the combustion rate is fast, and the flame is short. The form of the coal nozzle: The form of the coal nozzle affects the mixing of wind and coal, and the more evenly the wind and coal are mixed, the faster its combustion rate.

The influence of the volatile content of coal on the length of the flame: bituminous coal with high volatile content can catch fire at a place close to the nozzle, and the flame is longer, while the coal with low volatile content is the opposite (because the ignition temperature decreases with the increase of volatile, the volatile content is different, the ignition point is different from the nozzle, the volatile content is high and the ignition is early, and the heating process of the coal lasts a long distance, so the flame is long. Most of the heat energy of coal with low volatile content can be released in a short distance, so that the flame concentration flame is short, and sometimes local high temperature phenomena occur).

In the process of calcining clinker, the situation in the kiln changes greatly, so there are many factors that affect the length of the flame. Assuming that other conditions remain constant, the factors that cause the flame to grow are as follows:

1. Large exhaust air;

2. Less material; 3. Low calcination temperature;

4. a slow train; 5. The pulverized coal has a coarse temperature, large ash content, low volatile content, and more fixed carbon;

6. The position of the coal pipe is high, and it extends into the kiln more;

7. Coal is small once, and the wind temperature is yours for one or two times;

8. The diameter of the coal pipe is large, the pin pulling angle is small, and the flat tip is long;

9. Stop the kiln and burn.

Assuming that other conditions remain constant, the factors that cause the flame to be short are as follows:

1. Small exhaust;

2. Thickness of material layer;

3. The kiln speed is fast;

4. The primary wind is strong, the secondary wind is small, and the coal is appropriate;

5. Burning and pressing, high temperature of the fire point;

6. The volatiles of pulverized coal are high, and the primary and secondary air temperature is high;

7. The position of the coal pipe is too low, partial material, and outer;

8. The diameter of the coal pipe is small, the angle is large, the flat tip is short, and the wind wing is installed.

The temperature of the rotary kiln The kiln flame high temperature temperature measurement and detection device.

Reactors, rotary kilns, hot blast furnaces and other kilns are widely used in metallurgy, building materials and other industries, and it can complete different process operations such as drying, roasting and volatilization of materials. With the different processes of the industry, the types of materials, heating methods, fuels, flame temperatures, negative pressure control conditions in the kiln are also very different, but in most cases temperature control is required, so the temperature in the kiln is a key parameter, which directly affects the output, quality and energy consumption of the product.

The factors that affect the flame of the rotary kiln are as follows:

1. Large exhaust air;

2. Less material; 3. Low calcination temperature;

4. a slow train; 5. The pulverized coal has a coarse temperature, large ash content, low volatile content, and more fixed carbon;

6. The position of the coal pipe is high, and it extends into the kiln more;

7. Coal is small once, and the wind temperature is yours for one or two times;

8. The diameter of the coal pipe is large, the pin pulling angle is small, and the flat tip is long;

9. Stop the kiln and burn.

Assuming that other conditions remain constant, the factors that cause the flame to be short are as follows:

1. Small exhaust;

2. Thickness of material layer;

3. The kiln speed is fast;

4. The primary wind is strong, the secondary wind is small, and the coal is appropriate;

5. Burning and pressing, high temperature of the fire point;

6. The volatiles of pulverized coal are high, and the primary and secondary air temperature is high;

7. The position of the coal pipe is too low, partial material, and outer;

8. The diameter of the coal pipe is small, the angle is large, the flat tip is short, and the wind wing is installed.

The main factors affecting the flame shape of the rotary kiln are the combustion speed of pulverized coal and the speed of air movement in the kiln. Its specific contents are as follows: (The influence of the quality of pulverized coal and its dosage Volatile matter of pulverized coal:

Pulverized coal with low volatile content is easy to form a flame with a long black fire head, a short high temperature part, and a high local flame temperature. The pulverized coal with high volatile content (although the fire is fast, but because the volatile fractionation and combustion take a certain amount of time, and the gas layer on the surface of the coke particles is thick, so the oxygen around the coke begins to burn is not much, so it forms the flame that is close to the kiln head, the temperature is slightly lower, and the high temperature part is longer. Ash content of pulverized coal:

When the coal ash content increases, the calorific value decreases, and the combustion speed slows down, so that the flame elongates and the temperature decreases. Moisture of pulverized coal: When the moisture increases, the flame temperature decreases and the black fire head is elongated.

The amount of coal: the greater the concentration of coal in the primary wind, the more pulverized coal is.

The longer the primary and secondary air mixes, the longer the duration of the ignition. Therefore, when the primary wind does not change, the amount of coal used increases, and the flame will elongate. (Influence of the position and shape of the injector Nozzle position:

When the coal injector position is in the kiln position of the secondary air, the primary and secondary air mixture is weak, prolongs the combustion time, and makes the flame elongate. If it is strengthened before the secondary air enters the kiln position.

Mixing between the primary and secondary winds to shorten the flame, etc. Please refer to the detailed information.

The reasonable distribution of the appropriate flame and the temperature in the kiln plays a very important role in the improvement of clinker production and quality, the thickness and length of the kiln skin, the life of the kiln lining, the fuel consumption, the temperature of the cylinder, the reduction of pollution and the protection of the environment. Therefore, the cement rotary kiln has strict requirements for the flame, especially in the new dry rotary kiln, the shape, temperature and strength of the flame are required to be appropriate for the calcination of clinker in the rotary kiln. Ensure that the heat exchange of high thermal efficiency can be carried out over the entire flame length, and at the same time, the kiln skin can not be locally overheated and the peak temperature appears, and it should be able to adapt to the change of kiln conditions.

To meet these requirements, the following conditions should be met:

1. The air supply volume of the primary air should be as small as possible, and the coal air can be mixed fully and evenly, and the secondary air with high temperature can be fully used as much as possible to achieve the purpose of increasing production and saving energy.

2. The combustion efficiency and the burnout rate of pulverized coal are high, which avoids the deterioration of clinker quality and process accidents caused by incomplete combustion.

3. The flame shape is good and stable, which adapts to the needs of the change of kiln conditions, and the temperature field distribution in the kiln is reasonable to avoid the peak temperature and the flame has no pulse.

4. The shape of the flame can be adjusted easily and flexibly according to the needs.

5. The pulverized coal burner is safe and reliable, has a long service life, does not temper, and can adapt to high temperature and wear resistance.

6. The adaptation to coal quality is necessary to be strong, and it can adapt to the needs of coal quality fluctuations.

7. The ignition is easy to heat up quickly, so as to shorten the ineffective time and reduce the labor intensity.

8. There should be hot flue gas backmixing in the flame jet to increase the ambient temperature of pulverized coal combustion and reduce the oxygen concentration, which not only increases the combustion rate, reduces the burnout time, but also reduces the generation of NO, which is conducive to environmental protection.

Once the wind is strong, the flame grows, and it has nothing to do with how fast the gas burns. If your central wind (i.e. straight wind) is fully turned on, then the larger the flame will be, and generally the central wind of our kiln is turned on to the maximum. Do you mean that the wind will blow the flame out under what circumstances?

As long as the fan at the end of the kiln and the primary air are turned on (Hz of normal firing), there will be no negative pressure in the kiln, and it will not go out. Other than that. The ignition point of the gas is 530, and as long as the temperature inside the kiln is higher than that, even if there is no open flame, the gas will ignite on its own.

Once the wind turns on very strongly, it will not blow out the fire.

You can use an electric welding handle to simulate it. In actual production, the primary wind mainly affects the shape of the flame, and cannot guarantee the complete combustion of the gas, so it is not only the bigger and the longer. In the case of a certain gas, the primary wind changes from small to large, and the flame length changes from short to long and then shorter.

The above are all in actual production, and I am just a beginner. The matter of my unit is burning, I hope it will help you.

The firing temperature of cement clinker in rotary kiln is 1300 1450, and the flame temperature should reach 1540 1700, and the flame temperature should be about 350 500 higher than the firing temperature. When the flame temperature is too low, it is difficult for clinker to be burned, and the f-cao is high, and the ignition loss is large. If the flame temperature is too high, it is easy to produce clinker overburning, burn out the kiln lining, and often occur the phenomenon of red kiln, which not only wastes energy, but also does not reduce the quality of clinker. The new dry pre-decomposition kiln is different from other kiln types, and the production requirements:

Thin material fast burning:. The material heats up quickly in the kiln, and due to the thin material layer, the faster the heat transfer and reaction speed, the lower the energy required for clinker firing, and the higher the kiln output. In order to increase the heating rate of the material, it is necessary to increase the flame temperature, under the premise of ensuring the quality of the clinker, the shorter the residence time of the material in the high-temperature firing zone, the better the quality of the fired clinker, and the higher the strength of 28d.

In order to shorten the residence time of the material in the high temperature zone, it is necessary to increase the flame temperature and speed up the kiln, that is, "thin material fast burning". Therefore, increasing the flame temperature is the basic premise of increasing the kiln output and reducing the consumption, the flame temperature is not high, the kiln speed can not be accelerated, and even run or underburn. Information in:

During the combustion process of pulverized coal in the rotary kiln, heat transfer (heat transfer to low-temperature pulverized coal) and movement towards the kiln tail are also carried out. Pulverized coal is ejected by the burner, first preheated and dried, and then the volatile matter ignites and burns, generating heat, the temperature rises, and the flame is formed - the black fire head (the distance at which the pulverized coal starts burning after ejection) and the burning flame surface (at the interface between the black fire head and the white flame). The flame surface is subject to two moving forces:

One is the moving phenomenon of heat transfer to the unburned pulverized coal at the back, and its velocity is called flame propagation velocity; The second is the combustion velocity (ejection velocity) of the phenomenon of forward (kiln tail) movement by the burner. When the propagation velocity is equal to the ejection velocity, there is no "tempering" or "stalling".