With the control demand of serious pollution, high efficient pulverized coal fired industrial boiler with its excellent combustion technology and flue gas pollution control technology in coal burning equipment take charge as chief of. The classification of the burner and the principle of part of the burner are as follows.
Burner classification
1, the pulverized coal burner with a precombustion chamber
This is the earliest and the most widely used new type pulverized coal burner in our country. Burner with a precombustion chamber by the pre combustion chamber of refractory material or heat resistant steel plate manufacturing.
2, blunt body burner
This type of burner is the development of Huazhong University of science and technology at the beginning of 80s, the scope of its application after the burner with a precombustion chamber. Used in boiler burning coal, lean coal and anthracite, used as flame stabilizing and improving combustion. It is in the corner of the burner at each corner of an air vent outlet, set up a bluff bodies - bluff body, the pulverized coal airflow circulation in the wake of the bluff body, the entrainment of high temperature flue gas for fuel ignition and flame stabilization. After the fire of the pulverized coal in the furnace consists of four corner tangential combustion.
3, flame stability vessel burner
The ship type pulverized coal burner was successfully developed by Tsinghua University in the middle of 80s. The structure for the installation of a ship in the conventional pulverized coal burner flame stabilizer once in the air outlet, and the center of a small oil gun ignition. After adopting the structure, on the pulverized coal into the furnace to bypass it later, away from a nearby air jet to form a waist. High temperature and high concentration of pulverized coal and proper oxygen concentration area is formed between the two sides of the outer edge of the beam waist, a good fire source ignition of pulverized coal air flow, thereby stabilizing combustion in furnace.
4, burner
Burner using centrifugal force or inertial force of a pulverized coal air flow into rich and poor powder powder flow flow two streams, respectively through different nozzle into the combustion chamber. In this way, a high concentration of pulverized coal powder can be separated under the condition that the total amount of wind is constant. Because the high concentration pulverized coal flow has good ignition and flame stability, it does not require a particularly strong heat return flow.
In this way, not only to achieve a simple and easy to strengthen the fire, but also to avoid the disadvantages of heat backflow. This burner has wide adaptability to coal, not only for lignite burning high ash low quality bituminous coal and high water, is also used for burning anthracite and lean coal.
Burner principle
The 1 is the use of pulverized coal burner, the air mixture flow, namely primary air flow into rich and poor powder powder flow flow two streams, which can improve the concentration of pulverized coal rich powder flow in the premise of a total change of wind.
2 rich powder fuel flow in the excess air coefficient is less than 1 under the condition of combustion, the powder flow in the fuel lean combustion excess air coefficient greater than or close to 1 under the conditions of the two streams together so that the total coefficient of excess air burner is kept in a reasonable range.
The separation principle of 3 shades
(1) the centrifugal type pulverized coal concentrator used in W flame boiler;
(2) the centrifugal force generated by turning the pipeline has been used in the pulverized coal concentration, four corner tangential combustion furnace on;
Conical axial separator for shutter;
(3) with pulverized coal concentrator swirl blade, fan for burning high moisture lignite coal mill direct firing system.
4 principle of steady combustion
The concentration of pulverized coal in the powder flow is increased, that is, the amount of the air current is decreased, the heat is reduced, the flame speed is increased, and the fuel is burning in advance. However, the concentration of pulverized coal is not better. If the pulverized coal concentration is too high, it will affect the lack of oxygen due to volatile combustion, particle heating rate decreased, but the flame speed decreases, the ignition distance stretched, and will produce soot. The optimal concentration of pulverized coal and coal on the optimum value of low volatile coal and coal is higher than that of bituminous coal. Rich powder flow after the fire, the fire source provides for the poor powder flow, which will enhance the stability of the whole fire, burning torch, thereby expanding the boiler without oil combustion and load adjusting range and adaptability of coal.
5 to reduce pollution
Pulverized coal combustion with NO and a very small amount of NO2 generation, they are collectively referred to as nitrogen oxides, NOX said, is a harmful gas emissions. To reduce the amount of NOX generated, the flame temperature is low, the oxygen concentration in the combustion zone is low, and the residence time of the fuel in the high temperature zone is short. Burner can reduce the emissions of NOX in the products, it is also a kind of low NOX burner.
6 prevent the residue
Pulverized coal particles reducing atmosphere at high temperature, ash melting point of coal ash is greatly reduced, so that when the dust in the smoke to contact the heating surface or the furnace wall, could still maintain a softening state or molten state, sticking on the wall surface, the formation of slag.
The invented burner, a pulverized coal air flow along the horizontal direction of separating light, pulverized coal is located in the back side, the side of the water wall, the water wall near the pulverized coal concentration decreased, the increase of oxygen concentration, the reducing atmosphere decreased, increased the melting temperature of ash, can reduce the possibility of furnace slagging. At the same time, concentration of pulverized coal in the fire side, thus obtaining a fiery, stable combustion