Structure of ordinary boilers

Ordinary boiler is by boiler tube system, combustion chamber. According to the working process of the boiler, the boiler can be divided into two parts: boiler body and combustion equipment.

The boiler body includes water wall, boiler tube bundle, superheater, economizer and air preheater, etc. They are all various forms of heating surface. The heat energy of the flue gas is transmitted to the public office through these heating surfaces. The other side of the boiler body is the working medium - water, steam or air. Both water and steam have high pressure when working, so the main parts of boiler body should have the ability to withstand stress, and the boiler body should also have good heat transfer performance.

Combustion equipment includes coal hopper, coal gate, boiler row, air chamber and furnace wall, furnace arch, etc. Their role is to feed the fuel into the fuel chamber, provide the conditions required for combustion, and complete the combustion process of the fuel. The form of combustion equipment mainly depends on the type of fuel and the mode of combustion. The traditional combustion mode of industrial boilers in China is mainly layer combustion, that is, coal formation is burned on the grate. The grate can be fixed or mechanized, such as chain grate. The combustion equipment should be suitable for the combustion of different kinds of coal, ensure the timely ignition and burning of fuel, and have a certain combustion intensity, which can provide heat energy for the boiler.

In general, the working process of a layer-fired industrial boiler with coal as fuel is that the raw coal is fed into the coal hopper by the coal conveyer, and the coal in the coal hopper can fall directly on the chain grate moving slowly forward. Enter the combustion chamber through the coal gate. The air in the combustion chamber is supplied by the air chamber under the grate. The high temperature flue gas produced by fuel combustion transfers heat to the water wall around the combustion chamber in the form of radiation exothermic, and then enters the convection flue through the slag-proof pipe. The convection flue is separated by smoke wall, and the flue is equipped with superheater and boiler tube bundle. The function of the superheater is to heat the saturated vapor from the pot tube into superheated vapor. The use of steam is different, and the requirements for superheated steam temperature are different. Superheater is generally composed of carbon steel or alloy steel pipe made of serpentine tube in rows. The diameter of superheater tube is about ∮30~50 mm.. The The boiler tube bundle is a cluster of tube bundles connected with the upper and lower boiler tubes. The water in the tube absorbs the heat of the flue gas and evaporates. The steam produced ∮50~70 mm.. The The flue gas scour the superheater and boiler tube bundle to release heat and enter the tail flue. The tail flue is equipped with economizer and air preheater and other heating surfaces. The flue gas temperature entering the tail flue is generally 400~500℃, and the economizer and air preheater are used to absorb this part of the flue gas heat. The economizer is made of bent rows of carbon steel pipes and is also made of cast iron pipes. The feed water temperature of industrial boiler is relatively low, generally between 20~105℃. The economizer is used to heat the boiler feed water. It can effectively absorb the heat of the flue gas and reduce the temperature of the flue gas. Air preheater is also made of steel pipe heating surface. The flue gas flows through the pipe and the air scour the tube bundle horizontally outside the pipe. The cold air inhaled by the fan absorbs part of the heat of the flue gas in the air preheater and is heated to a certain temperature into the air chamber of the grate. The lower temperature flue gas after heat release is discharged into the atmosphere through the induced fan and chimney. The lower the flue gas temperature discharged into the atmosphere. It shows that the more heat is absorbed, the higher the degree of heat energy is used and the higher the thermal efficiency of boiler.