How To Maintain The Combustion Temperature Of Dual Fuel Burner


How To Maintain The Combustion Temperature Of Dual Fuel Burner
The dual fuel burner is the embodiment of modern combustion technology in the industrial combustion equipment industry. The injection velocity of high-temperature combustion products at the outlet can reach 100 m/s~300 m/s. It has the technical advantages of energy saving and controllable flame momentum. China has been widely used in the steel, chemical, light industry, and other industries of various heating furnaces.

The dual fuel burner consists of an oil nozzle and an air regulator. The oil nozzle is arranged on the axis of the air conditioner to atomize the oil into small droplets, spray it into the combustion chamber at a certain diffusion angle (also known as the atomization angle), mix it with the air sent by the air conditioner, and ignite it. There are two main types of nozzles: pressure atomization and dual fluid atomization. The pressure atomizing oil nozzle is composed of a splitter plate, a rotary plate, and an atomizing plate. The oil pressure is generally 2~3 MPa.

The oil rotates at high speed in the vortex plate, ejects through the central hole, and decomposes into small droplets under centrifugal force. The average diameter of atomized oil droplets is less than 100 microns. The dual fluid atomizing nozzle uses steam or compressed air as the atomizing medium to accelerate the oil cracking and atomization. The Y-shaped nozzle using steam as the atomizing medium is named because the steam passage and oil passage form a Y-shaped oblique intersection. Dual fuel burner has the advantages of a large load regulation range and low steam consumption.

In order to achieve complete combustion of dual fuel burner, gas and air enter the combustion chamber through multiple nozzle holes. The gas jet and the air jet collide one by one and mix evenly. The direction of the resultant jet vector should be parallel to the main axis of the combustion chamber. The jet penetrates another jet, causing uneven mixing. In order to reduce NOx generation, partition combustion is adopted. The combustion temperature in the front zone is lower than that in the rear zone, and the combustion temperature at the outlet of the combustion chamber is higher.

The front zone is lean combustion, the rear zone increases oxygen supply and the excess air coefficient at the combustion chamber outlet α=1。 This design can not only reasonably distribute air, ensure complete combustion and prevent the generation of CO, but also maintain low combustion temperature and reduce the generation of harmful gas NOx. The combustion chamber wall is cooled. The combustion chamber is full of high-temperature combustion products. The metal chamber wall must be fully cooled to work safely.

In the design, the air is used to flow in the chamber outside the combustion chamber to absorb the heat conducted by the chamber wall to ensure that the chamber wall works within a safe temperature range. At the same time, preheating the air can promote complete combustion and increase the theoretical combustion temperature. In the local high-temperature area of the combustion chamber nozzle, a layer of gas film is specially designed to protect the metal wall. Due to the above design, the service life of the dual fuel burner can reach 3 years.