Classification of boilers

Classification by use

Power station boiler: boiler for thermal power plant, large capacity, high parameters, new technology, strict requirements. It is the main product of Shanghai boiler Factory.

Industrial boiler: boiler that provides steam or hot water in the process, heating and cooling of textile, printing and dyeing, pharmaceutical, chemical, oil refining, paper making, etc., in various industries. It is one of the products of Shanghai Boiler Factory.

Domestic boilers: boilers that provide low-parameter steam or hot water for industrial and mining, enterprises and institutions, hotels, service industries, etc. Such boilers are in great demand and there are many manufacturers all over the country.

Special boilers: such as double-working medium two-steam cycle boilers, nuclear fuel, ships, locomotives, waste liquid, waste heat, direct current boilers and so on.

Classification by pressure

Atmospheric boiler (non-pressure boiler, that is, a boiler that works at a normal atmospheric pressure)

Low pressure boiler (pressure less than or equal to 2.5MPa)

Medium pressure boiler (pressure less than or equal to 3.9MPa)

High pressure boiler (pressure less than or equal to 10.0MPa)

Ultra-high pressure boiler (pressure less than or equal to 14.0MPa)

Sub-critical boiler (pressure between 17-18MPa)

Supercritical boiler (pressure between 22- 25MPa)

According to the type of working medium and output state

The working medium of the boiler is water, and the output working medium is water steam. Steam can be divided into saturated steam and superheated steam. The working medium of the boiler is water, and the output working medium is unsaturated hot water. Special working medium boiler Boiler working medium other than water chemical fluids, such as mercury mercury steam boiler.

According to the body structure type

Boiler shell boiler combustion and endothermic evaporation are completed in a cylinder body, it has horizontal and vertical points, such as early orchid development, cannon furnace and so on. The main heating surface of the water tube boiler is a tube boiler, which is a major improvement of the early boiler, and the safety and reliability are greatly improved.

Boiler drum boiler, boiler drum placed outside the fire side is not heated boiler, there are double drum, single drum and multi-drum type, pot drum has horizontal type, vertical type, etc.

By fuel or energy type

When a boiler burns a different fuel, it is called a boiler of that fuel or a mixed boiler of two fuels. A boiler in which fuel is burned on a bed of material, or grate furnace or layer furnace. It is generally a lump of granular raw coal with a maximum capacity. Chamber combustion boiler fuel in the furnace or furnace combustion, generally pulverized coal boiler, oil, gas boiler, etc., the contemporary maximum capacity of the unit, also known as suspended combustion boiler, there are semi-suspended combustion boilers between layer combustion and chamber combustion, such as mechanical coal thrower, wind thrower boiler and so on.

Cyclone combustion boiler Pulverized coal or fine coal burning in the cyclone boiler, it has two kinds of horizontal and vertical, the cyclone combustion heat intensity is very high, suitable for low ash melting point coal and difficult to fire coal.

The boiler of boiling combustion is placed on the fire bed with granular fuel, and the fuel layer is pulsated and boiled into fluidization under high pressure wind blowing, also known as the fluidized bed boiler.

According to the slag discharge method

There are solid and liquid slag discharge, solid slag discharge is well known liquid slag discharge coal ash at high temperature combustion to form a liquid, flow into the water to crack into translucent crystals for building materials.

According to the flue gas pressure in the furnace

The negative pressure system is established when the flue gas pressure from the furnace to the boiler outlet is lower than the atmospheric pressure, so that the suction force of the induced draft fan is greater than that of the supply fan. Conversely, when the supply pressure of the fan is greater than the suction capacity of the induced draft fan, micro-positive pressure combustion is formed. Micro-positive pressure combustion can reduce the loss of air leakage heat, but the sealing requirements of the boiler are much higher. The pressurized combustion boiler increases the pressure of the combustion flue gas to several atmospheres, and the pressure flue gas is used as the working medium of the gas turbine, which promotes the generator to generate electricity or drives the air compressor to obtain higher pressure air as the combustion medium.

It is divided in a circular manner

The flow circulation of the working fluid in the water wall of the natural circulation boiler relies on the specific gravity difference of the working fluid between the rising and falling tubes to establish a circulating pressure head to produce a natural circulation, which is only suitable for subcritical pressure.

The auxiliary circulation boiler is equipped with a circulation pump between the water wall and the downcomer to overcome the flow resistance and ensure the safety and reliability of the water circulation. It is suitable for boilers with sub-critical and near-critical pressure.

Direct current boiler from the water to the superheated steam outlet, relying on the feed pump pressure once through the heating surface of the boiler, it is suitable for high pressure above to more than a supercritical pressure.

The boiler with controllable forced recirculation system is attached to the evaporation section of the DC boiler to maintain good operating conditions of the water wall during low load or start-up, and to enter pure DC operation at high load.

The principle of the low-rate circulating boiler is similar to that of the controlled circulating boiler, which reduces the circulating ratio of the water wall to about and speeds up the evaporation rate.

According to the overall layout

The overall arrangement of the boiler generally has a variety of "D" type, "T" type, "π" type, "tower" type and "box" type, and so on.

According to the boiler room layout

The boiler is all in an open environment

Part of the boiler is in the open air, and the other part has a simple house. The boiler is all in the boiler room.

According to the ventilation

Natural ventilation boiler Boiler combustion air depends on the chimney to draw the wind naturally inhaled, are used for small boilers.

Mechanical ventilation balance ventilation boiler Large boiler smoke system resistance is large, the air required for combustion is forced into the fan, the combustion flue gas is drawn out by the induced draft fan, to maintain the resistance balance of the smoke duct.

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