Design and Application of Coal and Oil Burners
The drying of raw materials is usually electric heating, microwave, freezing, hot air, solar energy, etc. At present, most of the drying equipments used in the building materials industry are boiling furnaces. Such hot air drying methods have large drying power and raw material performance. Features that are less affected by pollution. However, there are also disadvantages such as the large size of the equipment, the large number of equipment operators, and the generated exhaust gas that has a certain impact on the environment. To this end, Jiangsu Haike has developed kerosene dual-purpose burners, which meet the requirements for drying. Solve the many shortcomings of boiling furnace equipment.
1. Requirements for the design of coal and oil burners:
1) The combustion power is large and must be adapted to the conditions in the building materials industry that require a lot of hot air. Under normal circumstances, the demand for high-temperature hot air ranges from tens of thousands to 100,000 cubic meters per hour.
2) The fuel has strong adaptability, ie it can burn pulverized coal and burn diesel.
3). The pollution produced is small. Now the environmental protection requirements are more and more stringent. Diesel fuel produces almost no pollution, and the pollution resulting from the combustion of pulverized coal is also less than the pollution produced by the burning of coal gangue in a boiling furnace.
4) The equipment has a small footprint and is easy to operate. Relatively difficult to ignite the boiling furnace, high-pressure fan is difficult to adjust the amount of air, coal and oil burners to achieve a real start, no one guarded. Moreover, the device's appearance is greatly reduced.
2. Structural features of coal and oil burners.
Coal and oil burners are equipped with both a pulverized coal burner and a diesel burner. Both burners share a rotating furnace body. Compact structure. Seamless integration.
2.1, Diesel Burner
(1) Mounting Flange (2) Rear Cover (3) Ignition Electrode (4) High-Temperature High-Voltage Cable (5) Ignition Transformer (6) Servomotor (7) Air Inlet Flange (8) Relay Box (9) Fire Mirror (10) Three-way block (11) Solenoid valve (12) Electric eye (13) Oil pump (14) Coupling (15) Oil pump assembly (16) Motor
Working principle: After power on, the motor runs and the ignition transformer starts to discharge after 10-20 seconds. The fuel in the fuel tank is sucked into the oil pump after passing through the filter. After being pressurized by the oil pump, it is sent out. The solenoid valve then opens and the fuel passes through the nozzle mist. After the spurts are ejected and mixed thoroughly with the air, ignition is performed by the ignition electrode for 10 seconds. The ignition transformer stops working and the burner works normally. For the two-stage and three-stage burners, the low-ignition solenoid valve is opened first. After the combustion is stabilized, the high-ignition solenoid valve is opened. The sprayed oil mist encounters a low-flame flame and ignites, and the high-flame flame is stabilized and then enters. Normal combustion state.
Main structural description of diesel burners
The fuel injector is the most critical part of the burner. Its operation will directly affect the operation and output of the burner. The burner uses a high-pressure centrifugal atomizing nozzle. This nozzle is used when the injection pressure is greater than 0.6MPa. A good atomization effect can be obtained. With the increase of the injection pressure, the atomization quality is also improved, and the injection amount is increased. On the contrary, the injection pressure is reduced, the atomization quality is reduced, and the injection amount is reduced. The fuel injector consists of a nozzle housing 1, an atomizer 2, a pressure screw cap 3 and an oil filter screen 4 (see figure below). The injection hole on the nozzle housing and the chute on the atomizer 2 are important structures to ensure the atomization quality of the fuel. The atomization angle and fuel injection amount are critical, and it should be ensured that the dimensions are accurate and clean. Any damage, deformation and dirt will seriously affect the normal operation of the fuel injectors and the burners, so they should be cleaned and replaced regularly. The pressure screw cap 3 should be tightly pressed on the atomizer 2, otherwise it will affect the fuel atomization effect and the fuel injection amount. The oil filter 4 is used to filter fuel to prevent impurities from entering the nozzle and affect the normal operation of the nozzle. It should be made of a 200-mesh filter and should keep the filter 4 clean and complete.
2.1.2. Burner head
The head of the burner is the part where the burner atomizes, ignites, and burns the fuel. It consists of a diffuser (1), a stabilizing disk (2), an injector (3), and an ignition electrode (4). , Combustion cylinder (5) and other components (see below). The combustion air sent from the blower enters the burner head from the air supply short pipe (5) and is divided into two parts when it flows into the diffuser drum (1). The first part is rotated when it passes through the fume cup (2). Mixed combustion. The formation of a high-temperature flue gas recirculation zone in the diffuser (1) plays a crucial role in stabilizing the flame. The higher the ratio of the air passing through the flame-stabilizing disk to the combustion air, the better the stability of the flame. The flame at the time of combustion is also short; the second part of the air flows into the diffuser through the annular passage between the outer edge of the fume cup (2) and the diffuser and is then combusted with the fuel. Since the diffuser has a small volume and a short length, only a small amount of fuel is burned in it. On the other hand, the rest of the fuel is mixed with the combustion air. On the other hand, it is injected into the combustion chamber of the furnace and continues to burn to form a certain length of flame. Burning heating equipment needs. The relative position of the ignition electrode and the stabilizing disk is very important. As shown in the figure below, the spark generated by it must be within the range of the flammable gas, and the flow rate of the gas should not be too high, otherwise it will not be easy to ignite.
2.1.3. Throttle and its regulating mechanism
Flap is used to adjust the amount of air entering the burner. There are three methods for adjusting the damper:
(1) Manual throttles
Where single-section burners are adjusted by hand, the fixing screws on the damper are loosened first. According to the size of the fuel injection, the opening of the damper is adjusted so that the amount of combustion air matches the injection quantity. Then tighten the fixing screws.
(2) Hydraulic cylinder damper
It uses the angle of rotation of the hydraulic cylinder to control the opening of the damper.
(3) Servo Motor Adjustable Air Door
It uses the angle of the servomotor to control the throttle opening.
2.1.4. Gear Pumps
Providing fuel for diesel burners
2.1.5. Electric eye. Fault red light and controller
(1) Electric eye (flame monitor)
Electric eye is a device that monitors the flame. If the flame is not on after the start of the burner, or the flame suddenly goes out during operation, the electric eye will not feel the luminosity of the flame and the controller will stop everything within 10 seconds. operating. At the same time, a red light is on the controller.
(2) Fault red light
When the burner is not properly started and operated for some reason, the controller will stop all operations of the burner within 10 seconds and the fault red light will illuminate. In this case, you should carefully check all the possible causes of the failure, and eliminate them one by one, then press the fault red light for a few seconds and the burner will restart.
The controller controls the entire operation of the burner.
2.2 Pulverized Coal Burner
(1) Main motor of coal duster (2) Coal speed reducer (3) Coal duster (4) Coal lowering valve (5) Upper coal bunker (6) Coal injection pipe (7) ) Diesel burner (8) Furnace body (9) Coal and oil common fan (10) Support platform
Working principle: Small granular coal is fed into the coal duster through the silo and plug valve. The internal hammer of the coal grinding machine grinds the coal particles into about 200 mesh of fine pulverized coal. The large impeller at the outlet of the coal pulverizer is rotated at a high speed, and the fine pulverized coal is injected into the pulverized coal pipe through the pulverized coal pipe. In the rotating furnace, a high-speed rotating pulverized coal flow is formed. The igniter ignites the diesel fuel that is ignited and burned by the atomized diesel fuel and comes into contact with the flow of high-speed rotating coal dust to form a stable combustion flame. At this point, the injection of fuel and the continuous combustion of pulverized coal continue to provide continuous hot air for the drying of the material.
Pulverized coal burner main structure:
2.2.1 Coal duster mainly consists of coal hopper, coal feeding screw, shell, main shaft, hammerhead, liner, fan, splitter and motor.
There are bearing seats at both ends of the housing, deep groove ball bearings, and the shaft between the bearing seat and the shaft is sealed with a felt ring, and the rear bearing seat is provided with a seal ring. The bearing seat is fixed at both ends of the machine body, and both end caps are seal. The main body is composed of two parts: a crushing room and a fan room. Two sets of working devices are installed on the rotating main shaft. The drive is driven by a motor. The belt is driven by a V-belt. The body is composed of upper and lower shells. The upper shell has coal inlets and inlets. Vents, air inlets use baffles to adjust the amount of air intake. After the pulverized coal and air are mixed in the upper part of the fan room, they are pulled out. The lower shell feet and the bottom of the channel steel are fixed with bolts. The inside of the crushing chamber is fixed with a liner. And the side plate, in the fan room, fixed fan body on the shaft.
2.2.2 Ignition oil supply system consists of storage tank, gear oil pump, oil pump motor, flame nozzle, overflow valve and high pressure hose.
2.2.3 Furnace consists of a tail unit, a combustion chamber, a furnace body rotation drive, etc.;
The tail unit integrates fans, coal inlet pipes, ignition holes, observation holes, and diesel burners. Pulverized coal and air are combined at the tail to form a high-speed rotating pulverized coal flow to realize swirling combustion. The combustion chamber is made of steel plate and made of refractory bricks. It can withstand high temperatures up to 1200°C. The furnace drive consists of a large gear ratio reducer, supporting rollers and belts to ensure that the furnace is at a very low speed. Under conditions of rotation, to prevent the formation of large coking coal powder combustion process.
2.2.4 Support platform and guide rail assembly ensures that the furnace body can move back and forth in the axial direction. Clearing and overhauling.
3. The coal and oil dual-burner has been used in many units such as Nanchang Brother Building Materials Co., Ltd., Anhui Yisheng Yiju Building Materials Technology Co., Ltd., Shenzhen Yidong Dongyang Building Material Co., Ltd., etc.; general reaction burner power, energy The utility model has the advantages of high efficiency, less environmental pollution, and simple and convenient operation. Compared with the boiling furnace, the operator can be reduced. In short, the purpose and requirements of product development have been achieved.