Fuel and smoke air system

Fuel and smoke air systemxsJBoiler Burner

The main fuel used for boilers in our country is coal.Generally large boilers and power station boilers often burn pulverized coal, so it is necessary to have a pulverized coal system.As is shown in the picture, the coal dropped from the original coal bunker is sent to the coal feeder for pulverizing.The coal is dried at the same time in the grinding process, and the drying medium is usually hot air.The cold air is fed into the air preheater by an air blower, where it absorbs the heat of the smoke and becomes hot air.Part of the hot air through the discharge machine after the high pressure head into the coal mill, in the coal heating and drying at the same time to carry the pulverized coal left the coal mill, it can be seen that this part of the hot air in addition to as a drying medium, also plays the role of conveying coal powder, usually this part of the hot air is called a primary wind.In the direct blowing system as shown in the figure, after the gas-powder mixture comes out of the coal mill, it is sent directly to the burner through the coal powder pipeline, and then it is sprayed into the furnace chamber for combustion.It should be pointed out that in the intermediate silo pulverization system, the primary air carries the pulverized coal into the pulverized coal separator, where the pulverized coal is separated from the airflow and stored in the pulverized coal bunker, and the pulverized coal is supplied to the burner from the pulverized coal bunker by the pulverized coal feeder according to the load requirements.It can also be seen from the figure that another part of the hot air from the air preheater enters the furnace directly through the air outlet of the burner to provide the air needed for pulverized coal combustion. This part of the hot air is called secondary air.xsJBoiler Burner

Pulverized coal releases a lot of heat when burned in the furnace.There is a wall of water - cooled pipe which is composed of metal pipe.However, due to the limitation of heat load and furnace volume, the smoke temperature at the furnace outlet is generally as high as about.In order to make use of the high temperature flue gas, the flue is also equipped with superheater (divided into several stages), reheater, economizer and air preheater.High temperature flue gas flows through these heating surfaces in turn and radiates heat to them by convection and radiation.The exhaust temperature from the air preheater is generally around.At this time, the flue gas has been unable to reuse, is sent to the dust collector for separation, the vast majority of the flue gas carried fly ash away, and then by the fan into the chimney, finally into the atmosphere.xsJBoiler Burner