Boiler classification method based on the respective criteria and types of boilers

Classification of boilers based on boiler pressure

Steam pressure of boiler is less than or equal to 20Kg/cm², called low pressure boiler or low pressure boiler.

The steam pressure of the boiler is in the range of 20 – 45Kg/cm². Medium pressure boiler or medium pressure boiler

The steam pressure produced by the furnace is in the range of 45 to 80 Kg/cm². High pressure boiler or high pressure boiler

The steam pressure produced by the furnace is more than 80kg/cm², super high pressure boiler

Classification of boilers by fuel source

Boilers use different fuel sources; solids (firewood, coal, wood…) liquid (oil) or gas (gass) to burn to boil water, thereby generating heat to meet different needs for the production process and life human. Based on different fuel sources, boilers are classified according to their respective fuels.

Classification of boilers by fuel sourceClassification of boilers by fuel source

Coal fired boiler

Wood fired boiler

Rice husk fired boiler

Boiler burning DO oil, gass, biomass

Classification of boilers according to criteria of combustion technology

According to the development and improvement of the boiler through the stages, the boiler is designed to use different combustion technologies, to burn the fuels. Some types of boilers use outstanding combustion technology:

Classification of boilers according to criteria of combustion technologyClassification of boilers according to criteria of combustion technology

Chain grate boiler: The fuel will be put on the grate, and the chain grate will move to bring the fuel slowly into the combustion chamber automatically.

Static log boiler: It is using the technology of burning fuel on a fixed burner, putting fuel into the combustion chamber by manual method.

Fluidized bed boiler: An industrial boiler using fluidized bed combustion chamber technology, burning fuels in the fluidized layer. The boiling layer is made up of millions of grains of sand, slag or some kind of special material.

Classification of boilers according to the movement criteria of heat and water

Fire tube boiler is a type of furnace with a tubular combustion chamber design and water surrounding the combustion chamber. From the tube of the combustion chamber, the heat will radiate to heat the surrounding water and then convert it into steam. This type of boiler has a limited pressure of about 30Kg/cm², ie a capacity of about 30 tons/h. Fire tube boilers are usually applied to small and medium sized factories; or as auxiliary boilers on ships.

Water tube boiler: The opposite of fire tube boiler. Water is directed inside the tubes inside the combustion chamber. Through the wall of the water pipe, thermal energy will transfer heat and heat the water inside the tube. This type of boiler can produce hot steam with pressure up to 180 bar, capacity can reach 300 tons/h. Some large boilers used in thermal power plants can have a capacity of up to 2000 tons/h.

Combined boiler: This type of boiler has a combination of fire tube boiler and water tube boiler.

Classification of boilers according to the movement criteria of heat and waterClassification of boilers according to the movement criteria of heat and water

Classification of boilers by tube design

Horizontal or horizontal cage boiler: The boiler body is designed to be horizontal to the floor.

Vertical cage boiler or vertical boiler: The boiler body is designed to be vertical and cylindrical

Classification of boilers according to the circulation of water and steam

Natural circulation boiler: The water and steam flow is automatically recirculated based on the difference in pressure and volume.

Forced circulation boiler: This type of furnace is designed to use a circulation pump to force the flow of water and steam to circulate in the pipeline.

Besides the above boiler classification criteria, in fact the boiler products market will be a combination of the above criteria with an option in that criterion. Some boiler models will modify the combination of options in different criteria to make the most of resources, optimize costs while ensuring efficiency:

Waste heat boiler – Heat recovery boiler

This type of boiler: the heat source from the exhaust gas from the boiler itself and other equipment reuses. This both saves operating costs and helps protect the environment. Type of waste heat boiler – heat recovery boiler is commonly used in chemical plants.

This type of waste heat boiler adopts water tube boiler design with natural or forced circulation mechanism. In order to achieve a suitable flow in the tube and to ensure sufficient water content at the outlet of the steam generator during each operating and operating cycle of the boiler. Each waste heat boiler system is equipped with a reheater, an economizer, a superheater and a superheater.

Cooling boiler

This type of cooling boiler: heat will be taken from the engine hot air inlet. Its heat input is about 900 degrees Celsius and operates mainly as cooling devices. That is, the boiler must react to cooling heat as quickly as possible to reduce the temperature. Avoid thermal fractures and decomposition reactions generated as well as heat exchange at the very high gas inlet.

Tubular design coolers shall be installed hermetically sealed with no gaps at the tube-to-screen connections, at least on the air inlet side, so that heat exchange can be facilitated without loss of heat. waste.

Circulating fluidized bed boiler

The furnace uses a fluidized-bed combustion chamber, a fluidized bed made up of sand grains, coal slag, or some other materials to burn fuel, combined with recovery and recirculation technology using particles with auxiliary equipment to convert chemical energy in fuel into steam energy.

Circulating fluidized bed boilerCirculating fluidized bed boiler

Structure of fluidized bed boiler includes:

Recirculating boiler combustion chamber: is the place where the fuel combustion takes place. Conventional combustion chambers are divided into 2 floors: upper and lower floors.

Equipment for separating and recovering solid particles: There are usually 2 types of recovery by impact principle or centrifugal principle.

Solid particle circulation device

Additional heat exchanger

Steam boiler once evaporating

One-time evaporator boiler is a type of boiler commonly used in large-scale thermal power plants. The furnace regularly operates at a steam temperature of up to 650 degrees C, a pressure greater than 230 bar. In other manufacturing industries including small and medium-sized thermal power plants, this type is rarely used The reason is that the single-evaporation boiler requires the water used to be demineralized.

The above is a boiler classification method, which can be based on many different criteria to classify types of boilers, in order to help users visualize and grasp the outstanding features of each type of furnace and have choice to suit your needs. However, in reality, there will also be boiler product models that have many different combinations of factors and are not included in the list of boiler types according to the above criteria. The article shares the most overview of method information for boiler classification. Hope the information in the article will bring a lot of useful information to you.

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