How to maintain the combustion temperature of an oil gas dual purpose burner
The dual purpose burner for oil and natural gas is a manifestation of modern combustion technology in the industrial combustion equipment industry. The injection speed of high-temperature combustion products at the outlet can reach 100m/s~300m/s. It has technological advantages such as energy conservation and controllable flame momentum. Various heating furnaces have been widely used in industries such as steel, chemical, and light industry in China.
The dual purpose 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, which are sprayed into the combustion chamber at a certain diffusion angle (also known as atomization angle), mixed with the air sent out by the air conditioner, and ignited. There are two main types of nozzles: pressure atomization and dual fluid atomization. The pressure atomizing oil nozzle is composed of a splitter, a rotating plate, and an atomizing plate. The oil pressure is generally 2-3 MPa.
Oil generates high-speed rotational motion in the vortex plate, is sprayed out through the central hole, and decomposes into small droplets under the action of 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 rupture and atomization of the oil. The Y-shaped nozzle, which uses steam as the atomizing medium, is named because the steam channel and oil channel form a Y-shaped oblique intersection point. The dual purpose oil and gas burner has the advantages of large load regulation range and low steam consumption.
In order to achieve complete combustion of the dual purpose burner, gas and air enter the combustion chamber through multiple nozzle holes. The gas jet and air jet collide one by one, mixing evenly. The direction of the synthesized 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 the generation of NOx, partitioned 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 for lean combustion, the rear zone increases oxygen supply, and the excess air coefficient at the outlet of the combustion chamber α= 1。 This design can not only distribute air reasonably, ensure complete combustion, prevent the generation of CO, but also maintain a lower combustion temperature and reduce the generation of harmful gas NOx. The combustion chamber wall is cooled and filled with high-temperature combustion products. The metal chamber wall must be fully cooled in order to work safely.
In design, air is used to flow in the chamber outside the combustion chamber to absorb the heat transmitted by the chamber wall, ensuring that the chamber wall operates within a safe temperature range. Meanwhile, 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 purpose oil and gas burner can reach 3 years.