Reasonable Selection, Maintenance, and Energy Conservation of Burners in Asphalt Mixing Plants

Reasonable Selection, Maintenance, and Energy Conservation of Burners in Asphalt Mixing Plants
The development of self-control burners has formed a series of products, including light oil engines, heavy oil engines, gas engines, and dual-purpose oil and gas engines. Reasonable selection and maintenance of burners can save a lot of money and extend the service life of combustion systems. With the changing demand for fuel, the quality requirements for burners are also increasing. Good ignition performance, efficient combustion efficiency, and wide adjustment ratios have always been the goals pursued by various construction units. However, there are many burner manufacturers and different brands, and only when selected properly can the above requirements be met.
1、 Selection of 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 the process of delivering fuel to the nozzle for atomization through a high-pressure pump, and then mixing it with oxygen for combustion. It has the characteristics of uniform atomization, simple operation, low consumables, and low cost. Nowadays, most highway construction machinery adopts this atomization mode.
(2) Medium atomization is a combustion process that involves pre mixing fuel with compressed air or pressurized vapor pressure of 5-8kg to the periphery of the fuel nozzle. Its characteristic is that it does not require high fuel requirements (such as poor quality oil such as residue), but it has more consumables and higher costs. Currently, this type of machine is less commonly used in the road construction machinery industry.
(3) Rotating cup atomization refers to the process in which fuel is released from atomization through a high-speed rotating cup plate (about 6000 rpm) and can burn high viscosity residual oil. However, this model is expensive and the rotor is prone to wear and tear, requiring debugging. At present, the highway construction machinery industry generally does not adopt this model.
2. Burner structure: Automatic control burners can be divided into gas supply system, gas supply system, control system, and combustion system.
(1) Gas supply system: To ensure complete combustion of fuel, sufficient oxygen must be provided, and different fuels have different requirements for air volume.
(2) Fuel supply system: Fuel must have a reasonable combustion and mixing space in order to fully burn. The transportation methods of fuel are divided into high-pressure transportation and low-pressure transportation. The pressure atomization burner adopts a high-pressure conveying method, with a pressure requirement of 15-28 bar. The rotary cup atomization burner adopts low-pressure conveying and requires a pressure of 5-8 bar. Currently, the oil supply system of road construction machinery mostly adopts high-pressure conveying.
(3) Control system: Due to the particularity of construction conditions, the road construction machinery industry chooses burners with mechanical control and proportional adjustment.
(4) Combustion system: The shape of the flame and the combustion process depend entirely on the combustion system. The flame diameter of the burner generally does not exceed 1.6m, and it is best to adjust the width, usually set at around 1:4~1:6. When the flame diameter is too large, it can cause serious carbon deposits to form on the furnace barrel. If the flame is too long, it can cause the exhaust gas temperature to exceed the standard and damage the dust removal bag. It can also scorch the material or make the material curtain covered with oil stains.
2、 Maintenance of burners
1. Check the fuel regulating valve. If the surface of the screw or nut is too dirty or rusty, it is necessary to repair or replace the regulating valve.
2. Oil pump: Regularly check if the pump is intact, the internal pressure is stable, and replace damaged sealing devices or leaks. When using hot oil, check that all oil pipes are well insulated.
3. The filter installed between the oil tank and the oil pump must be regularly cleaned and checked for excessive wear to ensure smooth fuel delivery from the tank to the oil pump and reduce the possibility of potential component failure. The Y-shaped filter on the burner should be cleaned regularly, especially when using heavy or residual oil, to prevent clogging of the fuel injector and valve. During operation, check the pressure gauge on the burner to see if it is within the normal range. 
4. For burners that require compressed air, check if the pressure device generates the required pressure in the burner, clean all filters on the supply pipeline, and check for leaks in the pipeline.
5. Check if the inlet protection device of the combustion atomization air blower is installed correctly, and if the fan casing is not damaged or leaking. Observe the operation of the blades, and adjust the blades to eliminate excessive noise or vibration. The belt drive blower should be regularly lubricated and tightened with bearings to ensure that the blower can generate rated pressure. Clean and lubricate the air valve joint to ensure smooth operation. If there are any obstacles in operation, replace the parts. Check if the wind pressure meets the usage requirements.
6. Regularly clean the fuel injector and check the spark gap of the ignition electrode (about 3 millimeters).
7. Regularly clean the flame detector (electric eye) to determine whether the installation position is correct, whether the temperature is appropriate, if the position is incorrect, or if the temperature is too high, it can cause unstable photoelectric signals and even fire interruption.
2、 Reasonable use of combustion oil
Combustion oil is classified into light and heavy according to its viscosity equivalence. Light oil can achieve good atomization effect without heating. Before using heavy oil or residual oil, it should be heated to ensure that the viscosity of the oil is within the allowable range of the burner. The results can be measured using a viscometer to find the optimal fuel heating temperature. The residual samples should be sent to the laboratory in advance to determine the heating value. After a period of use, the burner should be inspected and adjusted for heavy or residual oil. When inspecting dryers and bag filters, a combustion gas analyzer can be used to check whether the fuel is fully burned and whether there is oil or oil smell, to avoid fire and oil blockage. Due to changes in oil, the accumulation of oil stains on the atomizer will increase, so regular cleaning is necessary. In addition, after the work is completed, turn off the burner switch first, and then turn off the heavy oil heating. When the machine is shut down for a long time or the weather is cold, switch the oil circuit valve and clean the oil circuit with light oil, otherwise the oil circuit will be blocked or difficult to ignite.
With the rapid development of highway construction, the effective utilization of combustion systems can not only extend the service life of mechanical equipment, but also reduce engineering costs and save a lot of funds and energy.