The control system of natural gas closed burner is composed of electric valve, sensor, PLC remote control cabinet and computer control software.
Each layer of nozzle adopts partial pressure control. After entering the torch area, the natural gas is divided into four paths, controlled by electric valves, respectively into the first, second, third and fourth layers of the burner nozzle. The whole device runs automatically under the centralized supervision of the automatic ignition system.
The burner nozzle and igniter are controlled by pressure transmitter as trigger condition. When the pressure is higher than the ignition set value, the igniter starts to ignite the long flame and burns normally; When the pressure is higher than the first layer of burner nozzle valve set value, long open fire normal combustion, the first layer of burner valve automatically open, natural gas into the first layer of burner nozzle combustion; When the pressure is higher than the second layer of burner nozzle valve set value, long open fire normal combustion, the second layer of burner nozzle valve automatically open, natural gas combustion by the first layer, the second layer of burner nozzle combustion at the same time; When the pressure is higher than the third layer burner nozzle valve set value, long open fire normal combustion, the third and fourth layer burner nozzle valve automatically open, the first, second, third and fourth layer burner nozzle burning at the same time.
When the pressure is below the lower limit of the burner nozzle valve, the burner nozzle valve will be closed. When the pressure is below the lower limit of the fourth burner nozzle valve, the fourth burner nozzle valve closes, etc.; Turn off the flame when the pressure is below the lower limit of the flame. The four-layer burner nozzle burns automatically according to pressure changes to achieve stable exhaust emissions and prevent frequent start and stop of the torch.
(1) External axial flow air duct
The nozzle of the outer axial flow duct adopts semicircular hole structure, which has a certain inclined taper, reduces the wind resistance and improves the injection intensity. The external axial wind is sprayed through the semi-conical holes intermittently, and the high-speed air sprayed can completely absorb the high-temperature secondary air. The outlet area of the external axial flow duct can be stepless adjusted, and then the outlet wind speed of the external axial flow wind can be adjusted.
(2) pulverized coal air duct
Pulverized coal air duct is arranged between the external axial flow air duct and the cyclone air duct. The pulverized coal diffuses rapidly under the action of external axial wind and cyclone and burns rapidly. At the same time, the axial wind and swirling wind can control the direction and distribution of coal powder in the kiln, and effectively adjust the flame shape and flame temperature distribution.
(3) Cyclone air duct
The cyclone pipe is arranged inside the pulverized coal pipe. Whirlwind through a number of conical semicircle spiral groove spray a number of high-speed whirlwind, cyclone effect, so that the coal quickly dispersed from the burner, reduce the concentration of coal powder, improve the contact time and contact area of coal powder and air, so that the coal can quickly combustion, improve the combustion efficiency of coal powder. The outlet area of the cyclone pipe can be stepless adjusted, and then the outlet wind speed of the external cyclone can be adjusted.
(4) Eddy current air duct
The vortex duct is arranged inside the vortex duct, and the vortex wind is sprayed through a plurality of spiral Angle cyclones. By adjusting the axial displacement, the jet Angle of the eddy wind can be adjusted to adjust the shape of the flame. Through the whirlwind, the burning flame is more concentrated and the flame is more stable.
Biogas burner is composed of back pressure valve, flame arrester, manual maintenance valve, pneumatic valve, burner, exhaust hole, electrical control device, igniter and so on. Biogas burner is an advanced combustion equipment for reliable air emission after complete combustion of biogas. According to the inherent characteristics of biogas combustion, it effectively solves the above problems of general biogas combustion of air. Biogas burners are widely used in various industries of air emissions. Biogas burner system is easy to operate, safe and reliable. In order to ensure the reliability of the system, the imported automatic combustion control system is selected.
The burner consists of combustion chamber, ejector nozzle, support structure, combustion and flame monitoring system, flame arrester, main actuator, condensate discharge, PLC control cabinet and other components. The main body is 304 stainless steel, the combustion chamber is a double layer of stainless steel or ceramic fiber insulation. Large closed structure, built-in ceramic temperature module, suitable for durable combustion. Biogas project is becoming one of the important ways to improve agricultural efficiency and increase farmers' income. The use of biogas burner can effectively alleviate the hostility between village energy and environmental protection, end the national ecology, farmers get rich policy, take biogas production as the link, promote the village rich project, effective use of resources, reduce pollution emissions, production resource conservation and environmental protection society, End gas production, fertilizer synchronization, breeding, breeding priorities, farmers' income, agricultural efficiency, village urbanization policies.
During normal operation, the burner's spatial positioning protects the kiln surface. Life cycle of refractory materials. Barrel temperature and clinker quality will have a great impact.
Generally speaking, the front fulcrum of the burner is the centering point, and the back fulcrum is the controllable point. With the up, down, left and right adjustment of the rear fulcrum, the Angle between the center line of the burner and kiln barrel changes; The forward and backward movement of the burner car can change the distance of the burner into the kiln.
Burner datum positioning
Position of burner after feeding
(1) Increase the mixture of pulverized coal and combustion air, improve the combustion rate, and the fuel is completely stable combustion.
(2) Increase the means to adjust the air volume and wind speed of each channel to make the flame shape and temperature adjustment flexible and convenient, suitable for clinker calcination.
(3) Long service life of burner.
(4) Protect the lining material in the kiln and prolong the service life of the lining.
(5) Stabilize clinker quality and improve system output.
(6) Simple structure, convenient maintenance and replacement, reduce the impact of burner failure on the system running time.
(7) Minimize the amount of primary air, increase the utilization of high temperature secondary air, and improve the utilization rate of clinker recovery heat.
(8) The system resistance should be as low as possible to reduce the power consumption of the primary fan.
(9) it can reduce the emission of harmful substances (especially NOx).
(10) Use of low-grade fuel, enhance the comprehensive utilization of fuel, lower equipment prices and maintenance costs.
The role of the burner refractory mud is to connect the molding products, so that the brick joints between the refractory brick to prevent slag and metal melt through the brick joints into the internal refractory brick. Therefore, the burner refractory mud must have good construction performance. After barbecue heating, should have good sintering performance and enough corrosion resistance.
As refractory mud is the weakest link in the process of firebrick use, especially the refractory mud between the lining of firebrick determines the service life of firebrick to a great extent. Generally speaking, the burner refractory brick is red stone brick or low creep brick or cordierite brick, and the pipe part is andalusite brick or low creep brick. After pre-laying, the refractory brick polishing problem is found, so that the construction is more convenient and the ash seam is smaller.
Due to the severe temperature and erosion of burners and pipes, many andalusite bricks are constructed with high aluminum mud. In the process of use, refractory mud and brick bonding is not good, frequent thermal shock parts easy to shrink crack, ash crack increase, resulting in brick fall off or draw lots, affect the service life of furnace lining.
Because andalusite does not shrink at high temperature, low creep rate, small thermal expansion coefficient, strong chemical erosion resistance, strong thermal shock resistance, so in the burner and pipeline parts of the andalusite fire mud. Andalusite refractory mud with andalusite as the main raw material high strength, very stable.
Therefore, the refractory mud used for hot blast stove burner and pipe bricklaying must use andalusite mud, which not only has good spreadability, but also does not shrink stably at high temperature and improves the service life.
Burner design is the key factor to determine the combustion efficiency and flame type, and burner exit flow analysis is one of the best ways to verify burner design.
The burner used in the analysis consists of two concentric tubes arranged in a ring with a cyclone to provide oxidant (air or oxygen-rich air). In order to induce vortex of different strength, eight guide vanes with different angles are designed. The fuel injection mode and the ratio of fuel to oxygen-rich air determine the combustion mode of the burner. The burner can be changed from diffusion type to partially premixed type and vortex type. In this study, radial fuel injection was used to enhance mixing in the area near the burner outlet.
The test was carried out in a square chamber with a height of 1 meter and a cross section of 48x48cm2 under the action of one atmosphere pressure. The outer walls of the combustion chamber are water-cooled and lined with refractory material. In the V3V system, 250L/min of air was added to the annulus to test the non-reactive (flameless) flow condition. The volume velocity is about 4.7 m/s, and the alumina particles used for dispersing are used as tracers. The average diameter is around 1μm.
The measuring body includes the central axis of the burner, extending outwards and containing approximately half of the burner. The camera is mounted on the V3V-9000-TS(center left) and the laser is placed on the other side of the chamber. Because of the strong three-dimensional nature of flow, the V3V-9000-TS system is considered to be a very suitable tool for flow analysis. In addition, the high spatial resolution of 1mm3 in the results provides a very detailed understanding of flow details and is an effective method for validating burner designs.
In the heat energy equipment system, the selection of fuel burner is more important. So in the process of choosing a burner, what factors do we need to measure specifically?
High-end will choose imported, functional, of course, the price is high, the quality is relatively good;
What brand series of hot water heaters can be basically;
Diesel, heavy oil, liquefied natural gas, natural gas and so on, different fuel choice of burner categories are not the same;
The maximum thermal power after conversion is usually obtained by dividing the maximum thermal power you need by 0.8 to select the burner with the maximum power value in the nameplate logo. This is just a rough choice. The actual output of the burner is related to the environment (temperature, altitude, etc.), combustion chamber structure, flue, gas machine and gas pressure, valve selection, etc. The choice of burner will affect the later adjustment and use, whether it will be seriously used;
The old equipment will directly refer to the original, there is no basis to see the diameter of the installation hole of the original equipment, the position and space around the center of the installation hole, so that the selected fuel burner can be installed and debugable and maintained.
1.Adjustment of oil pump
The outlet pressure of the pump is set to 12bar. When the fuel temperature drops to below 5℃, the outlet pressure of the oil pump can be adjusted to 14bar to ensure the smooth ignition of the burner and improve the stability of the flame. When regulating the pressure, connect the oil pressure gauge to the pressure gauge interface of the oil pump, and rotate the pressure regulating screw to adjust the outlet pressure of the oil pump.
2.Adjustment of combustion head
The position value of the combustion head should be adjusted according to the requirements of different nozzle specifications. When adjusting, rotate the adjusting rod of combustion head with a 6mm wrench, and the ruler will move once every 3 turns. The holes in the head of the adjusting rod can help adjust the count. In no case shall the position value of the burner be greater than the specified value. The regulating rod rotates to the right (+ direction), the air volume increases, the air pressure decreases, the CO2 content in the flue gas decreases, and the combustion head is close to the nozzle, which is suitable for low temperature ignition. The regulating rod rotates to the left (- direction), the air volume decreases, the wind pressure increases, the CO2 content in the flue gas increases, and the combustion head is far away from the nozzle, which is suitable for ignition under normal conditions.
3.Adjustment of ignition electrode
Before installing the nozzle, loosen the screw, move the electrode head, and remove the nozzle. When the electrode head is fixed, the distance between the electrode head and the nozzle should be kept at 2-2.5mm, and the size between the two electrodes should be kept at 4.0±0.3mm to ensure the accurate ignition of the electrode head.
The automatic windshields are driven by hydraulic pressure to ensure that all windshields are open. When adjusting, loosen the screws, adjust the fixed windshield, and tighten the screws when reaching the appropriate position. When adjusting, check the smoke color of the burner and the burner burns completely.
Burner is an important equipment component of cement kiln firing system. In addition to factors such as clinker quality, refractory life in the kiln, clinker coal consumption, environmental emissions and so on, the durability of castable lining of burner will greatly affect the selection and collocation of burner. After the equipment is put into operation, the damage phenomenon of refractory castable such as peeling, crack and spalling often appears.
The first layer is pale yellow with obvious corrosion phenomenon, indicating that liquid phase is generated on the surface of castable. The second layer is white and has the most loose structure. The castable has completely deteriorated and is basically the crystallization accumulation of alkali and salt. The third layer is light black with dense structure, and aggregate particles in castable components can be seen. The 4 layers are gray with dense structure and no crystalline material is found. The matrix part and aggregate particles of castable can be clearly seen.
The mineral composition of the first layer is mainly anorthite (CAS₂), wollastonite (C₂S) and potassium feldspar (KAS6) phases. The analysis shows that the wollastonite (C₂S) in this position is caused by the adhesion of cement clinker on the castable surface of burner liner. Calcium feldspar (CAS₂) generation may be due to cement clinker in the calcium material penetration into the lining castable, and castable matrix part of the reaction generated. The production process of potassium feldspar (KAS6) may be that the vapor phase substance containing K is volatilized from the basic substance in the original combustion material during the high-temperature calcination process, which condenses and deposits on the surface of the burner castable after encountering with the substrate of the castable, and is generated by reaction with the matrix of the castable at high temperature. Both minerals are low melts, and liquid phase is produced by melting at high temperature, resulting in corrosion of the lining surface, which reduces the surface strength of castable and accelerates its wear.
New compounds such as KAS₂(white garnet) and KAS₄(potassium Nenet) from salt K that has infiltrated into the castable react with the matrix to form volume expansion, changing the composition and structure of the matrix and causing damage to the castable. On the other hand, after K salt penetrates into castable matrix, it gradually cools and deposits in the process of temperature reduction. Due to its low volume density, volume expansion will occur after deposition, resulting in damage of castable matrix. And because its mechanical properties are completely different from the original matrix, it may fracture or damage the castable matrix due to volume change under the action of thermal stress or temperature fluctuation. Fe₂O₃, Na₂O, MgO and other oxides as shown in Table 1.
At present, fully premixed condensing module boiler is widely used in residential district, school, office building, mall and large industrial and commercial service building heating, hot water and so on. But for the maintenance of this piece, many people may not know how to carry out maintenance, how to operate, and related matters needing attention.
Power off and restart the system. If the pressure is less than 0.5bar, water the system to 1 to 2 bar. If it is not necessary, please do not switch off the power supply of the module boiler, and keep the electricity on so that the module boiler is in the state of self-inspection and self-protection.
If the module boiler is not used in a short period of time, press the switch button to shut down, do not dial off the power supply, keep the gas connected, in case the anti-freezing function cannot start in winter.
Press the switch button to shut down the machine, turn off the power, turn off the gas valve, turn off the module furnace tap water inlet valve, and then empty the module boiler and heating system, in case of freezing the module furnace and heating system in winter, damage the module furnace and heating system.
4.Maintenance and maintenance
The modular boiler must be cleaned and maintained more than once a year. If the time limit is exceeded, the performance of the modular boiler will decline because of foreign matters in the pipes, causing abnormal noise and becoming the cause of failure.
The preparation work before starting
5, softening water equipment can run normally. The softened water should meet the standard of GB1576, the water level in the soft water box is normal, and the pump runs without failure.
2, the burner into automatic cleaning, ignition, partial load, full load operation state;
3, when rising to a certain pressure, regular sewage should be carried out once, and check the water level in the furnace.
Inspection work in operation
4, patrol pump pressure is normal, there is no abnormal sound.
Accident stop furnace
1, when it is found that the boiler body produces abnormal phenomenon and the safety control device fails, the emergency disconnect button should be pressed to stop the operation of the boiler;
3, when the power fuel problems should be taken to press the emergency disconnect button;
4, when there is harm to the boiler or personal safety phenomenon should take emergency measures to stop the furnace.
Temporary power failure precautions
3, close the boiler continuous sewage valve to prevent other boiler faults;
4, close the oxygen supply valve;
5, according to the normal order of furnace stop, check whether the boiler fuel, gas, water valves meet the requirements of furnace stop;
Matters needing attention when gas is insufficient
3, observe the burning situation at any time, the flame is normal for wheat yellow.