I. Overview and Application Fields of Multi-channel Coal Powder Burners:

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

　　Multi-channel burners are technologically advanced, precisely processed, and use unique nozzle materials that are high-temperature and wear-resistant, resulting in a long service life and easy replacement.

　　II. Structural Performance Characteristics of Multi-channel Coal Powder Burners:

　　The coal powder burner utilizes the principle of large velocity difference in the same direction and co-flow, making full and effective use of secondary air, allowing the coal powder to quickly increase its temperature to the ignition point. A thick conical flame is formed as soon as it leaves the nozzle. The inner air uses stable plate technology to stabilize the flame and simultaneously reduce the nozzle temperature, increasing the nozzle service life, protecting the kiln skin, and extending the service life of the kiln lining. The primary air consumption only accounts for 5-7% of the theoretical air volume, resulting in significant energy saving. It can be used for lignite with 30-35% ash content and anthracite with about 10% volatile matter, and NOx emissions can be reduced by more than 30%.

　　The nozzle structure of the four-channel coal powder burner is arranged from the inside out: center air, swirl air, coal air, and direct-flow air channels. An ignition oil gun can also be installed in the center air channel according to user requirements.

　　Center air: flows out through small holes distributed on the central flame stabilization plate, with a flow rate of about 0.03%-0.05% of the total primary air volume. Its function is to adjust the negative pressure of the central recirculation zone of the jet and change the position and size of the high-temperature zone at the head.

　　Coal air channel: It is not easily blocked during use, and ceramics are bonded to easily worn parts to ensure service life. The direct-flow air channel is equipped with 12-16 circumferentially distributed nozzles. The special cavity linear design and processing precision of the nozzles ensure that the airflow from the nozzles is strong and powerful, with less energy loss, improving the momentum of the direct-flow outer air, improving the jet shape. In addition, a flame stabilizer is installed outside the direct-flow air channel to prevent premature flame dispersion and protect the nozzle head.

　　Years of rotary kiln burner engineering practice by Zhengzhou Zhongwei Environmental Protection Equipment Co., Ltd. has proven that the central disc flame stabilizer helps to form an internal recirculation zone. The geometric shape of the swirl air outlet will have an important impact on the various velocities in the jet and the position of the internal recirculation 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.

　　The inner and outer tubes of the swirl air channel of the coal powder burner adopt an axial telescopic structure, which can be adjusted in real-time according to the operating conditions, making the nozzle produce an expansion and extension effect. Operational practice has proven that this adjustment method is extremely effective in controlling the flame shape. The product of the mass flow rate m (kg/s) of the primary air of the coal powder burner and its ejection velocity is called the thrust M (N) of the burner. During combustion, the mixing rate of the secondary hot air and coal powder and the combustion speed of the coal powder both increase with the increase of the burner thrust, but excessive thrust will also produce negative effects. From the above, it can be seen that if the thrust or relative momentum value range is limited, the primary air velocity must be increased to reduce the primary air volume. It can be roughly estimated that the primary air velocity corresponding to the primary air volume is around 180-220 m/s. Currently, the velocity of most domestic three-channel burners has not reached this value.

　　The primary air velocity range of the four-channel coal powder burner is 160-250 m/s for the direct-flow outer air, 120-245 m/s for the swirl inner air, and 20-35 m/s for the coal air. Practical results have also confirmed that increasing the momentum at the primary air outlet can effectively reduce the primary air volume.

　　1. Good flame shape adjustability: The coal powder burner has multiple adjustment methods. Different proportions of inner and outer air and outlet jet shapes can be adjusted steplessly over a wide range without changing the total air volume, thus obtaining a flame shape that can adapt to any operating conditions.

　　2. Energy saving and consumption reduction: Due to the low primary air volume and the adjustable optimal ratio of direct-flow air and swirl air, it is conducive to the complete combustion of coal powder. Therefore, the four-channel coal powder burner can effectively reduce coal consumption. Practice shows that reducing the primary air volume by 1% can reduce heat consumption by 8.70-10.46 kJ/kg of fuel. At the same time, the secondary air temperature is significantly increased.

　　3. Strong adaptability to coal, suitable for low-volatile coal or anthracite: According to the combustion volatile content (%), the coal powder fineness is appropriately adjusted (generally, the percentage of residue on a 0.080 mm sieve is controlled at 0.5-0.75 times the percentage of volatile matter), and the thrust of the burner is adjusted accordingly, which can realize the use of low-volatile coal or anthracite for rotary kiln calcination.

　　4. Low NOx emissions: During normal operation, there is a negative pressure zone formed by the high-temperature flue gas recirculation at the head of the four-channel coal powder burner, which can avoid local high temperatures, and 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%, and the flue gas emissions meet 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, small system resistance, flexible and quick flame adjustment, convenient maintenance, and overall performance that reaches the level of foreign multi-channel burners.

　　6. New technologies and new materials ensure service life: Special wear-resistant spraying technology has been used on the easily worn parts of the four-channel coal powder burner, increasing the wear resistance of key parts 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, ensuring a service life of more than two years under conditions of 1100℃.

　　7. Convenient and flexible positioning adjustment: The suspension device of the four-channel coal powder burner can be extended and deflected according to the needs of the kiln conditions, adjusting its working position in the kiln to ensure stable and reliable thermal conditions. The inner and outer tubes of the swirl air channel adopt an axial telescopic structure, which can be adjusted in real-time according to the operating conditions, making the nozzle produce an expansion and extension effect.

　　Coal powder burners have been widely used in cement kilns, pelletizing kilns, lime kilns, lithium kilns, magnesium oxide kilns, alumina kilns, chromate kilns, ore dressing kilns, ceramsite sand, bauxite, kaolin, and various other kiln types in the building materials, metallurgy, chemical, and power industries.

　　Zhengzhou Zhongwei Environmental Protection Equipment Co., Ltd. classifies rotary kiln burners according to different fuels used: natural gas rotary kiln burners, liquefied gas rotary kiln burners, light hydrocarbon gas rotary kiln burners, coke oven gas rotary kiln burners, converter gas rotary kiln burners, blast furnace gas rotary kiln burners, calcium carbide furnace gas rotary kiln burners, ore furnace gas rotary kiln burners, diesel rotary kiln burners, heavy oil rotary kiln burners, mixed gas rotary kiln burners, mixed oil and gas rotary kiln burners, and mixed gas rotary kiln burners, etc.

　　Zhengzhou Zhongwei Environmental Protection Equipment Co., Ltd. undertakes "turnkey" projects for rotary kiln burners, automated control systems, kiln lining construction, desulfurization and denitrification equipment, and online monitoring devices, responsible for design, equipment manufacturing, and construction.

The ZED series four-channel pulverized coal burner is specially designed by Zhengzhou Zhongwei Environmental Protection Equipment Co., Ltd. for different kiln types, different pulverized coal characteristics, and different process conditions.