What are burners used in boilers? types of burners


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What are burners?

Most boilers get their heat from the hot water or steam from the combustion of the fuel that a burner requires.

The burners are to control the fuel and air mixture so that the combustion occurs smoothly and uniformly inside the furnace of the boiler.

The heat transfer from burners is often a complicated process because of the turbulent fluid flow, high-temperature chemical reactions, and spectral gaseous radiation.

Parts of burner:

The burner controls the amount of air supplied to the fire by some means. The media can vary from a single blade damper to variable input blades at the fan inlet and can include a VSD (variable speed drive) in the fan motor.

To provide stable combustion, the dampers or VSD must control the air flow without sticking or falling, which produces variations in the air flow. The dampers also have to control the flow without producing distortions in the flow of air to the burner.

Gas Burner:

Gas burners can be pre-mix and post-mix technique. Post-mix means gas and oil combines after they enter the furnace, premix burners are vice-versa.

premiximage imagePostmix

There are two options for the post-mix gas burners, which are usually identified as atmospheric burners or power burners. Atmospheric burners usually do not have fans or blowers to deliver the combustion air to the burner and rarely have draft fans.

Pre-mix burners are less used burners, Many operators that went from the burning process equipment to the boiler plant are comfortable with the premix burners.
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Oil Burners:

Fuel oil is injected into the burner using oil guns with burner tip at the end. The design and arrangement of the tip and the gun depend on the type of atomization system. There are two types of Oil burners.

  1. Vaporizing Burners

  2. Atomizing burners

Vapourising burner:

In the vaporization burners, the volatile fuel passes at low pressure through a tube adjacent to the flame, where the vaporization takes place. The vapour stream issues out of an orifice at a high velocity and entrains primary air.

Atomizing burner:

image

Atomizing burners have an arrangement for the atomization of liquid fuels before the actual combustion takes place. For atomization, initially, a jet or a thin film of liquid is obtained and allowed to emerge into the open atmosphere at a suitable velocity.

The design and arrangement of the tip and the gun depending on the type of atomization system.

Pressure atomizing burners have one or more tips at the end of a tube placed in the burner at the point where the oil must be injected to develop the air/fuel mixture.

There may be one or more burner tips with a burner gun. Differential pressure, air atomization and vapor burners need two pipes, one to transport the oil to the tip and another to supply air or steam or return the oil from the tip.