Detailed description of various gas burners
A gas burner is a gas combustion device that allows gas and air to enter the combustion area separately or mixed to achieve stable combustion. There are various types of gas burners, and the following will introduce several commonly used burners on industrial boilers through gas supply methods.
1、 Natural air supply burner.
According to the shape of the furnace, circular or rectangular burners can be selected. Low pressure gas flows out through the fire holes in the pipe and is pre mixed with air. This is a diffusion combustion method with a primary air coefficient, so it is also called a diffusion burner.
The burner has stable combustion, convenient operation, and a simple structure, which can meet the requirements of 300-400Pa low-pressure gas. However, the excessive air coefficient in the furnace is large, resulting in high smoke heat loss and incomplete combustion heat loss of gas. The combustion rate is low, and it can only be used in small capacity boilers.
2、 Injection type burner.
There are many types of this type of burner, which can be divided into two types based on their combustion methods: partial air premixing method and air premixing flameless combustion method. The injection medium used can be air or gas at a certain pressure, and the former requires an air blowing device.
1. Atmospheric injection burner.
This type of burner gas enters the injector at a certain flow rate from the nozzle, injects air once at the nozzle contraction, and then the two gases mix and flow into the burner head, flowing out of the fire hole and burning in the form of a natural flame.
This burner is also only used for small boilers and is suitable for various low-pressure gases. It does not require a blowing device, but has a large heat load and a bulky and bulky structure.
2. Air injection burner.
When the air pressure head is between 5000-600OPa, a negative pressure is formed through the nozzle through the injector contraction, and low-pressure gas is sucked into the four pipe holes. The two gases are mixed in the mixing pipe to form a uniform gaseous mixture, which flows to the outlet of the fire hole and then burns in a stable smoke and fire passage connected to the outlet.
This burner is a flameless burner that completely burns air premixed, with a small excess air coefficient at the furnace outlet and high combustion intensity. However, it requires a blowing device and consumes a lot of electricity. It is suitable for positive pressure furnaces with air preheaters.
3、 Blast type burner.
Blast burners generally consist of distributors, gas distributors, and fire channels, with a wide variety of types, commonly used including swirl and flat flow burners.
This type of burner has basically the same air distribution system as fuel burners. There are two types of gas splitters: single tube and multi tube. Its structure is simple, and the flame characteristics generated during combustion are similar to those of general swirl and direct flow fuel burners. The burner has strong mixing, perfect combustion, low excess air coefficient, but greater resistance.
4、 Imported gas burner.
It mainly includes three parts, namely gas system, air system, and control system.
The function of the gas system is to provide gas for combustion. Mainly composed of filters, regulators, pressure switches, safety valves, solenoid valves, flow control valves, distributors, etc.
The function of the wind system is to provide a certain amount and pressure for combustion. It mainly consists of a casing, fan impeller, air door, flame stabilizer (with air distribution plate), combustion head, shaft, sliding rod, air door dial, pressure measuring hole, combustion head adjustment screw, etc.
The function of the control system is to make the burner run according to the specified program. It mainly consists of wiring terminals, threading holes, control boxes, contactors, thermal relays, ignition transformers, ignition electrodes, electric motors (servo motors), photoelectric tubes, flame sensors, etc.