What is the flue gas flow of a boiler? The flow of the boiler flue gas system

Boiler flue gas flow:

1. The furnace burns to produce high-temperature flue gas.

2. The rise of high-temperature flue gas transfers heat to the heating surface.

3. The flue gas enters the tail flue under the action of the suction fan and continues to the economizer.

The preheater transfers heat.

4. The flue gas enters the dust removal device.

5. The flue gas passes through the suction fan.

6. The flue gas is discharged into the air through the chimney.

The main reason for the blackness of the flue gas of pulverized coal boiler is that the flue gas contains incomplete combustion of carbon. The main reasons are:

1. The pulverized coal particles are too pulverized, and the pulverized coal is too late to burn in the furnace and is carried out of the high temperature area of the furnace by the flue gas.

2. There is no process for changing the type of coal burned.

Circulating fluidized bed boiler.

Why is pollutant emission lower than that of pulverized coal boilers? Because the circulating fluidized bed combustion technology belongs to the clean coal combustion technology, the low temperature combustion and graded air supply make the NOx generation less, and limestone can be used as a desulfurization additive to achieve desulfurization in the furnace at low cost.

Generally, the problems of pulverized coal boilers are mainly the problems of the burner, the refinement of pulverized coal, and the transformation of the furnace for pulverized coal.

The flue gas flow of a boiler refers to the flow path of the flue gas produced after burning fuel in the boiler. Generally speaking, the flue gas flow of a boiler consists of the following parts:

1.Fuel combustion chamber:The fuel is burned in the combustion chamber, which produces high-temperature flue gases.

2.Flue:The flue gas enters the flue gas from the combustion chamber and passes through the pipes in the flue, and the flue gas temperature gradually decreases.

3.Flue gas purification equipment:The flue gas enters the flue gas purification equipment, such as dust collectors, desulfurization equipment, etc., for purification treatment.

4.Chimneys:The purified flue gas enters the chimney and is discharged into the atmosphere.

In the flue gas flow, the flow of flue gas is driven by a fan or induced draft fan inside the boiler. Whether the flue gas flow design of the boiler is reasonable or not directly affects the thermal efficiency and environmental performance of the boiler. Therefore, in the process of boiler design and operation, it is necessary to fully consider the optimization of flue gas flow and the selection of purification equipment to achieve higher thermal efficiency and better environmental protection effect.

Boiler flue gas flow of power plant: furnace combustion produces high-temperature flue gas--- high-temperature flue gas rises to transfer heat to the heating surface--- flue gas enters the tail flue under the action of suction fan, continues to transfer heat to the economizer and preheater--- flue gas enters the dust removal device--- flue gas passes through the suction fan--- flue gas is discharged into the air through the chimney.

The flue gas generated by boiler combustion passes through the tail heating surface (including economizer, air preheater, etc.), enters the dust removal, desulfurization, denitrification and other equipment and is sent to the chimney by the induced draft fan and discharged into the atmosphere, and the desulfurization and denitrification equipment of some power plants is located at the rear end of the induced draft fan.

The process of boiler flue gas system is as follows

(1) Combustion air: air blower - air preheater - secondary bellows - burner.

(2) Powder supply air: air - primary fan - air preheater - coal mill - burner.

3) Flue gas: flue gas - screen superheater - high temperature superheater - high temperature reheater - low temperature superheat low temperature reheater - economizer - denitrification device - air preheater - dust collector - induced draft fan - desulfurization tower chimney.

Boiler combustion system.

It is a system consisting of air flow channels that are pressurized and heated and sent to fuel preparation equipment and burners, flue gas channels that extract combustion products from furnaces and flues, flue gas flow channels that are discharged directly or purified to the chimney (or partially returned to the combustion system) and related equipment.

Chinese name.

Flue gas system. English name.

Definition of Flue Gas and Air System.

In the boiler combustion system, the cold air is pressurized, heated and sent to the coal mill and burner, the air duct, and the induced draft fan, flue gas pipe, pipe accessories and related equipment that extracts the combustion products from the furnace and discharges them to the chimney or part of the coal mill after purification.

Applied Disciplines. Electric power (first-level discipline), boiler (second-level discipline).

Look at what boilers too. I know.

The main function of a coal-fired boiler is to produce qualified steam for users, and to turn it into high-temperature and high-pressure steam by burning coal to heat the water in the boiler. The simple process is: feed water - economizer - steam drum - water wall - return steam drum - enter the superheater - supply steam to the user port, the boiler here is a general industrial steam drum boiler, with a water wall and superheater in the furnace, the boiler efficiency is relatively high.

Of course, there are many types of boilers, and the structure is also diverse, and the boiler process mentioned here is only one of the more representative industrial drum boilers.

Normally, the flue gas emitted from the boiler needs to go through the following treatment steps:

Flue gas pretreatment: Solid particles in flue gas are removed by equipment such as dust collectors.

Flue gas desulfurization: Sulfur dioxide in flue gas is removed by limestone-gypsum wet desulfurization, semi-dry desulfurization or sepiolite desulfurization.

Flue gas denitrification: Selective catalytic reduction (SCR) technology or selective non-catalytic reduction (SNCR) technology is usually used to remove nitrogen oxides from flue gas.

Flue gas dust removal: Harmony uses electrostatic precipitators, bag filters and other equipment to further remove fine particles and fine dust in the flue gas.

Flue gas debalance and wide water: reduce the moisture content in the flue gas through air preheater, condenser and other equipment.

Different boiler emission standards and the environment in which they are used will also affect the specific process flow.

The flue gas emitted from the boiler usually needs to go through the following processes:

Combustion process: The fuel in the boiler is burned under heating conditions, producing heat and flue gas.

Flue gas purification: The flue gas contains a certain amount of pollutants, such as sulfur dioxide, nitrogen oxides, particulate matter, etc., which need to be removed by purification equipment. Commonly used flue gas purification equipment includes electrostatic precipitators, desulfurization devices, denitrification devices, dust collectors, etc.

Flue gas cooling: After the flue gas is treated by the purification equipment, the temperature is high, and it needs to be cooled and cooled by equipment such as heat exchanger or condenser to prevent damage to equipment such as discharge pipes and chimneys due to high temperature.

Emission pipeline: After the flue gas is treated by the above process, it is discharged into the atmosphere through the discharge pipeline. In order to ensure the quality and safety of flue gas emissions, the discharge pipes need to meet certain norms and standards.

The substances contained in the flue gas are more complex, if we start from the particulate matter alone, we generally use the pulse bag filter to treat the particulate matter. If the flue gas contains sulfur, then we will use a spray tower for desulfurization. If there are nitrogen oxides, then we need to denitrify.

The flue gas flow in the boiler is as follows:

In combustion and flue gas systems, the blower feeds air into an air preheater to heat it to a certain temperature. The pulverized coal is ground to a certain fineness in the coal mill and carried by a part of the hot air from the air preheater into the furnace chamber through the burner. The pulverized coal and air mixture from the burner are mixed with the rest of the hot air in the furnace chamber and burned, releasing a large amount of heat.

After combustion, the hot flue gas flows through the furnace, the slag tube bundle, the superheater, the economizer and the air preheater in order, and then passes through the dust removal device to remove the fly ash in it, and finally is sent to the chimney by the induced draft fan to be discharged to the atmosphere.

Boiler flue gas flow of power plant: furnace combustion produces high-temperature flue gas--- high-temperature flue gas rises to transfer heat to the heating surface--- flue gas enters the tail flue under the action of suction fan, continues to transfer heat to the economizer and preheater--- flue gas enters the dust removal device--- flue gas passes through the suction fan--- flue gas is discharged into the air through the chimney.

Flue gas flow: the air enters the bellows after being heated by the primary air duct to the primary air preheater through the primary air duct, and participates in the combustion by entering the combustion chamber, and the air entering by the secondary fan is heated by the secondary air duct to the secondary air preheater, and enters the furnace at different heights to participate in the combustion through the secondary air duct arranged in high and low levels. The high-temperature flue gas generated in the furnace is exported to the superheater through the furnace chamber through the smoke partition wall, the folding smoke plate to the convection tube bundle, and after the heat exchange is completed in the convection tube bundle, the primary air preheater, the economizer, and the secondary air preheater to the exhaust gas dust collector, and the flue gas treated by the dust collector and desulfurized is discharged into the atmosphere through the chimney by the induced draft fan.