Reasonable selection of burners in asphalt mixing plants

Reasonable selection of burners in asphalt mixing plants
The development of automatic control burners has formed a series of light oil engines, heavy oil engines, gas engines, and dual purpose engines. Reasonable selection and maintenance of burners can save a lot of money and extend the service life of the combustion system. In recent years, many asphalt mixing plant enterprises have begun to look for suitable Alternative fuel to improve their competitiveness in the face of reduced profits due to rising oil prices. Due to the special factors of working conditions and use places, Roadworks machinery has been focusing on the use of oil-based burners. In the past few years, light oil has been used as the main fuel. However, due to the continuous rise in light oil prices, costs have rapidly increased. In recent years, most heavy oil burners have been used.
Although the demand for fuel is changing, the quality requirements for burners are becoming increasingly high. Good ignition performance, efficient combustion efficiency, and wider regulation ratio are often the goals pursued by construction units. However, there are also many burner manufacturers and different brands, and only the correct choice can meet the above requirements.
Choose different types of burners
1. According to the atomization method
The burner is divided into pressure atomization, medium atomization, and rotary cup atomization. (1) Pressure atomization is a high-pressure pump that transports fuel to the nozzle for atomization, and then mixes with oxygen for combustion. It has the characteristics of uniform atomization, simple operation, low consumption of materials, and low cost. At present, most road construction machinery adopts this atomization method.
(2) The medium atomization is premixed with the fuel to the periphery of the nozzle through 5-8kg compressed air or pressurized Vapor pressure. The fuel is premixed, which is characterized by low fuel requirements (such as poor residual oil and other oil products), but there are many consumables and high costs. At present, this type of model is rarely used in the road construction machinery industry.
(3) Rotating cup atomization is the process of removing fuel from the atomization by rotating the cup and disc at a high speed (approximately 6000rpm). It can burn poor oil, such as high viscosity residual oil. But the model is expensive, and the turntable is prone to wear and tear, requiring high levels of debugging. At present, the road construction machinery industry basically does not use this type of machine.
2. Burner according to machine structure
It can be divided into integrated spray gun type and split spray gun type (1) The integrated gun machine is a combination of fan motor, oil pump, chassis, and other control components. Its characteristics are small volume and small adjustment ratio, usually 1:2.5. It adopts a high-voltage electronic ignition system with low cost. High requirements for fuel quality and environment. Equipment with emissions below 120t/h and using diesel as fuel can choose this model, such as the German "Weissot".
(2) The split type gun machine divides the main engine, fan, oil pump unit, and control components into four independent mechanisms. Its characteristics are large volume, high output power, and the use of gas ignition systems, with a relatively large adjustment range, generally ranging from 1:4 to 1:6, and even up to 1:10. It has low noise, low fuel quality, and environmental requirements. This type of model is often used in the road construction industry both domestically and internationally, such as "Parker" in the UK, "Tanaka" in Japan, and "ABS" in Italy.
3. Burner
The structural automatic control burner can be divided into gas supply system, oil supply system, control system, and combustion system.
(1) Gas supply system
To fully burn fuel, sufficient oxygen must be provided. Different fuels have different air volume requirements. For example, each kilogram of oil must be completely burned at the standard pressure of No. 0 diesel, and 15.7m3/h of air must be distributed. To completely burn the heavy oil with a calorific value of 9550Kcal/Kg, 15m3/h of air must be distributed.
(2) The fuel supply system must provide reasonable combustion and mixing space for the complete combustion of fuel. Fuel delivery methods can be divided into high-pressure delivery and low-pressure delivery. Among them, the pressure atomization burner adopts a high-pressure delivery method, with a pressure requirement of 15-28 bar. The rotary cup atomization burner adopts a low-pressure conveying method, with a pressure requirement of 5-8 bar. At present, the fuel supply system in the road construction machinery industry mostly adopts high-pressure transportation.
(3) Control system The road construction machinery industry, due to the particularity of its operating conditions, selects burners with mechanical control and proportional regulation.
(4) The flame shape and combustion of the combustion system depend entirely on the combustion system. The flame diameter of the burner is generally required to not exceed 1.6m, and the adjustment effect is good, usually set at around 1:4~1:6. If the flame diameter is too large, it will cause serious carbon deposition on the furnace barrel. A long flame can cause the exhaust gas temperature to exceed the standard and damage the dust collection bag. It also burns the material or fills the material curtain with oil. Taking the 2000 type mixing plant of our unit as an example, the diameter of the drying cylinder is 2.2m and the length is 7.7m. The maximum flame diameter cannot be greater than 1.5m, and the flame length is preferably adjustable within 2.5-4.5m.