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What are the boiler combustion devices
Jun 24, 2018

The combustion process of various fuels is different, so the structure of the combustion device is also different. The combustion device can be divided into gas, liquid and solid fuels.

A gas fuel combustion device is usually called a burner. Its main function is to send gas and air to the furnace in a certain proportion and certain mixing conditions (also in the burner), and to meet the requirements of the flame during the heating process in the furnace. According to the mixture of gas and air in the burner, it can be divided into flame and flameless burner. The characteristic of the flame burner is that the gas and air are not mixed or only partially mixed in the burner, and the flame is sprayed to the furnace and then burning in the mixed edge, thus the flame is longer and has a clear outline. When the flame burner is used, the main means of strengthening the combustion and organizing the flame is to change the mixture of gas and air, such as dividing the gas and air into a lot of fine flow, making the gas flow and air flow intersecting at a certain angle, or using the swirling device to accelerate the mixing of the air.

The characteristic of the flameless burner is that the gas and air are evenly mixed in the burner, and the flame can be ignited immediately after the burner is ejected. The flame is very short and there is no clear flame outline. The flameless burner used in the industrial furnace is a jet burner, which is inhaled directly from the atmosphere by the injection of gas, and then mixed in the mixed tube and then completes the combustion reaction in the fire path made of refractory material.

In 60s, in order to meet the needs of the new heating process, a high speed burner with a gas outlet speed of more than 100 meters per second, a flat flame burner with a disc shaped Flame and a burner, and a preheater and a smoke exhaust device, have been formed as a whole. In order to reduce the environmental pollution caused by NOX, a new type of combustion device, such as low nitrogen oxide burner, has been developed.

A liquid fuel burning device is usually called an oil nozzle or nozzle. The fuel oil needs to be atomized and then burned, so the nozzle should have good atomization ability in addition to the basic performance of the general combustion device to ensure the full combustion of the fuel. According to the atomization method, the nozzle can be divided into a low pressure nozzle, a high-pressure nozzle, a mechanical nozzle and a rotary cup nozzle, wherein the low pressure nozzle and the high-pressure nozzle are widely applied.

The low pressure nozzle uses all the combustion air as the atomization medium, the atomization of the oil by the momentum of the air flow, the atomization of the particle size 80~100 microns, the air pressure is generally 2940~7840 PA, the flame in the combustion is generally 600~1400 millimeter. High pressure oil nozzle is used as atomization medium with steam or compressed air, and the pressure is generally up to (3~12) x 105 pa. Because the pressure of the atomizing medium is high, the velocity of the spray can reach or exceed the sound speed, so the atomization ability of the high-pressure oil nozzle is stronger than the low pressure nozzle, and the atomization particle size can reach 20~30 microns, but it needs to attach a passage to transport the combustion air. Road and corresponding airflow guidance facilities.

Industrial furnace for solid fuel combustion using solid fuel, commonly used block coal bed combustion method and pulverized coal jet combustion method. The combustion device with block coal bed combustion method is referred to as the combustion chamber, which is divided into an artificial coal combustion chamber and a mechanical coal combustion chamber. Lump coal is stacked on the grate manually or mechanically, and the combustion supporting air passes through the coal seam from the bottom of the grate to the completion of the combustion reaction.

The pulverized coal jet combustion method is the size of the pulverized coal to 50~60 microns. It is sprayed into the furnace with air, and the combustion reaction is completed through the pulverized coal burner during the movement, forming a flame with a certain shape.