The structure and classification of fuel burners
1. Combustion characteristics of oil
Oil is a liquid fuel, and the boiling point of liquid fuel is always lower than its ignition temperature, so the combustion of oil is actually carried out in a gaseous state. When the oil is burning, what directly participates in the combustion is not the oil in the liquid state, but "oil gas". Therefore, the combustion of oil droplets includes three processes of evaporation, diffusion and combustion, and they are carried out simultaneously. Has the following characteristics:
(1) Oil burns in the state of vaporization and gasification
(2) Oil has the characteristics of diffusion combustion
(3) The oil needs to be atomized before burning
(4) Oil has different thermal decomposition characteristics under different conditions
2. The structure of the oil burner
In order to make the fuel oil burn well, it is necessary to improve the atomization quality of the oil, so that the oil mist can be fully mixed with the air, which is mainly achieved by means of a burner. The burner is the key equipment of the oil-fired boiler, which consists of the fuel injection part (atomizer), the air regulator part, the ignition and combustion stabilization device, the electrical system, the motor and the servo motor, etc.
The fuel injection part is composed of oil pump, oil pump regulating valve, filter screen, oil preheater, solenoid valve, fuel injector, oil return regulating valve, etc. The air regulator part is composed of fan, air baffle, adjusting sleeve, shell, etc.
The ignition and stable combustion device is composed of a transformer, ignition electrode, etc., and the stable combustion device is composed of an air regulating plate and a combustion head
The electrical system consists of a flame sensor, a combustion program controller, a fuel heating controller, etc.
Motor The servo motor provides power for the fan machine, oil pump, damper adjustment, and oil return adjustment.
3. Oil atomizing nozzle
(1) Mechanization
The mechanical atomizing nozzle uses high oil pressure to spray oil from the nozzle hole at high speed to achieve atomization. The commonly used mechanical atomizing nozzles are centrifugal nozzles.
The simple mechanical atomizing nozzle is composed of atomizing sheet: swirl chamber, oil separator and nozzle nut, etc. The fuel with a certain pressure and temperature enters the tangential groove through the oil inlet hole and the oil equalization groove to obtain a high speed. , and then into the swirl chamber. The oil produces strong centrifugal rotation in the swirl chamber, causing the groove to pulsate, and is ejected from the nozzle hole to form a hollow conical film. Due to the turbulent flow of the oil, it diffuses through the nozzle hole, coupled with the centrifugal force, forms surface tension and is crushed into many fine oil particles to achieve the purpose of atomization.
(2) Rotor cup atomization
Its working principle is that the fuel oil is sent to the cup-shaped device rotating at a high speed of 3000~5000r/min through the hollow shaft. The mouth flies out and is atomized into very fine oil particles. At the same time, the fan blades installed on the same shaft blow out the primary wind along the mouth of the rotor through the guide vane, and the rotation direction of the primary wind is opposite to that of the oil droplets, so that the oil droplets are further atomized.
4. Classification of oil burners
The burner is a device that combines the fuel delivery and atomization device with the air regulating device through a circuit. Combined into one, called the integral burner. In addition to ensuring better fuel supply to the boiler and making it burn completely, it is also equipped with automatic control, alarm and protection devices. There is also a split foundation, that is, the oil system and the wind system are separated, so the circuit system is also separated. According to different fuels, burners are divided into light oil (kerosene and diesel oil), heavy oil (residual oil) and oil-gas dual-purpose burners.