Four channel coal powder burner: supporting cement kiln, ceramic sand pellet rotary kiln

1、 Overview and Application Fields of Four Channel Burners:

The HRQ series four channel coal powder burner is specially designed by Zhengzhou Zhongwei Environmental Protection Equipment Co., Ltd. using international advanced technology for different kiln types, coal powder characteristics, and process conditions. Its unique structure and reasonable process parameters ensure the full mixing of coal powder with primary and secondary air, with high combustion efficiency, high thermal intensity, and good flame shape. It has been repeatedly verified in practice and is easy to use and adjust.

At present, it has been widely used in various kiln types such as cement kilns, pellet kilns, lime kilns, lithium kilns, magnesium oxide kilns, alumina kilns, chromate kilns, beneficiation kilns, etc. in industries such as building materials, metallurgy, chemical engineering, and power generation. The four channel burner has advanced technology, precise processing, unique nozzle material, high temperature resistance and wear resistance, long service life, and easy replacement.

2、 Structural characteristics of four channel coal powder burner:

Structure and performance characteristics

The HRQ series four channel pulverized coal burner is composed of pipelines, nozzles, metal ripple compensators, butterfly valves, pressure measuring instruments, and protective layers.

Pipeline: including axial flow air duct, swirl air duct, coal air duct, central air duct, and fuel pipe. Because the fuel pipe is used for ignition, it is commonly referred to as a four channel system.

Nozzles: Made of special materials, the nozzle area of each series of burners can be adjusted to adjust the wind speed, which is one of the key components to ensure the shape and lifespan of the flame.

Metal ripple compensator: It is the main component that connects various pipelines, seals, and adjusts the shape of the flame.

Butterfly valve: used to regulate air volume.

Pressure measuring instrument: indirectly displays the spray speed of the air outlet inside the burner.

Protective layer: refers to the refractory pouring layer, which is poured by the user themselves.

The four channel coal powder burner utilizes the principle of co flow and large velocity difference in the same direction, fully and effectively utilizing secondary air to quickly raise the temperature of the coal powder to the ignition point, forming a thick conical flame just after leaving the nozzle. The internal air adopts stable plate technology to achieve stable flame effect, while reducing the nozzle temperature and improving the nozzle service life. It protects the kiln skin and extends the service life of the kiln lining. The primary air consumption only accounts for 5-7% of the theoretical air consumption, Remarkable energy saving. It can be used for 30-35% lignite and 10% anthracite. N0x exhaust emissions can be reduced by more than 30%. Specification performance parameters

The product structure of the four channel coal powder burner is a variety of problems encountered by Zhengzhou Zhongwei Environmental Protection Equipment Co., Ltd. in the engineering practice of the three channel coal powder burner. The nozzle structure of the four channel coal powder burner has been determined. From the inside out, it is sequentially divided into * air, swirl air, coal air, and DC air channels. According to user requirements, ignition oil guns can also be installed in the * air channel. * Air flows out through small holes distributed on the flame stabilizing plate, The flow rate is approximately 0.03% -0.05% of the total amount of primary air, and its function is to adjust the negative pressure in the jet * reflux zone, change the position and size of the high temperature zone at the head. The swirl air channel adopts a long spiral blade axial cyclone, which has a unique structure that not only reduces aerodynamic resistance but also generates sufficient swirl strength.

The coal air channel is designed scientifically, which is not easy to block during use and ensures the service life of easily worn parts with ceramic adhesive. The DC air channel mouth is equipped with 12-16 nozzles distributed in a circumferential direction, and the special cavity linear design and processing accuracy of the nozzle can make the outlet air flow of the nozzle strong and powerful, reduce energy loss, increase the outlet momentum of the DC external air, and improve the injection manifold. In addition, the DC air channel is also equipped with a flame stabilizing cover outside to avoid premature flame divergence, At the same time, it also plays a role in protecting the nozzle head

The engineering practice of Zhengzhou Zhongwei Environmental Protection Equipment Co., Ltd. has proven that the disc flame stabilizer helps to form an internal reflux zone. The geometric shape of the swirl air outlet plays an important role in the various velocities in the jet and the position of the internal reflux zone. Under the same swirl intensity conditions, using an expansion type extension port can increase the radial distance between the axial and tangential velocity peaks and the reverse mass flow rate. The inner and outer sleeves of the swirl air channel of the four channel pulverized coal burner adopt an axial expansion structure, which can be adjusted in real-time according to the working conditions to produce an expansion and extension effect at the nozzle. Operation practice has proven that this adjustment method is very effective in controlling the shape of the flame.

The product of the primary air mass flow rate m (kg/s) of a four channel pulverized coal burner and its injection speed is called the thrust M (N) of the burner. The mixing rate of secondary hot air and coal powder during the combustion process, as well as the combustion rate of coal powder, increase with the increase of burner thrust, but excessive thrust can also have negative effects. From the above, it can be seen that if the range of thrust or relative momentum values is limited, to reduce the primary air volume, it is necessary to increase the primary air speed. It can be roughly estimated that the primary wind speed corresponding to the primary air volume is around 180-220M/S. At present, the speed of most three channel burners in China has not reached this value.

The primary wind speed range of the four channel pulverized coal burner is 160-250M/S for direct current external air, 120-245M/S for swirling internal air, and 20-35M/S for coal air. Basically meets the aforementioned requirements. The effectiveness of industrial applications has also confirmed that increasing the momentum of the primary air outlet can effectively reduce the primary air volume

1. Good adjustability of flame shape: The four channel magnesium powder burner has multiple adjustment methods. The different ratios of internal and external air and the outlet jet flow pattern can be adjusted in a large range and steplessly under the condition of constant total air cooling, thus obtaining a flame shape that can adapt to any working condition

2. Energy saving and consumption reduction: Due to the low primary air volume and the adjustable ratio of direct and swirl air, which is conducive to complete combustion of coal powder, the four channel coal powder burner can effectively reduce coal consumption. Theory and practice have shown that every 1% reduction in primary air volume can reduce heat consumption by 8.70~10.46kJ/kg of fuel. Meanwhile, the secondary air temperature has significantly increased.

3. Strong adaptability to coal, which can be used for low volatile coal or anthracite; According to the volatile content (%) of combustion, properly adjust the fineness of pulverized coal (generally the 0.080mm sieve residue percentage is controlled at 0.5~0.75 times of the volatile content), and adjust the thrust of the burner accordingly, so that low volatile coal or anthracite can be used for rotary kiln calcination.

4. Low NOx emissions: During normal operation, there is a negative pressure zone formed by high-temperature flue gas reflux at the head of the four channel coal powder burner, which can avoid local high temperatures. The temperature curve along the kiln length changes smoothly, thus effectively suppressing the generation of "combustion NOx" and "high-temperature NOx", with a reduction of 20-30%. The flue gas emissions meet the national environmental protection emission standards.

5. Reasonable structure and excellent overall performance: The four channel coal powder burner has a beautiful appearance, complete supporting facilities, low system resistance, convenient and fast flame adjustment, convenient maintenance, and overall performance meets the level of foreign multi-channel burners.

6. New technology and materials ensure service life: Special wear-resistant spraying technology has been applied to the easily worn parts of the four channel coal powder burner, which increases the wear-resistant life of key parts of the burner by 5-10 times compared to ordinary steel. The head and nozzle of the four channel coal powder burner are made of heat-resistant steel material, which can ensure that the burner has a lifespan of more than two years at 1100 ℃.

7. Convenient and flexible positioning adjustment:

The suspension device of the four channel coal powder burner can expand and deflect according to the working  (Zhengzhou Zhongwei Environmental Protection Equipment Co., Ltd., Zhengzhou Deste Automation Equipment Co., Ltd.) undertakes the "general contracting" project of large-scale gas and oil fired kilns, automation control systems, desulfurization and denitrification equipment, kiln refractory material masonry, and online monitoring devices both domestically and internationally. It is a "one-stop" environmental protection kiln solution provider and implementer, For more technical details, please call (WeChat synchronization): 15713691937.

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