Questions&Answers

The functions and characteristics of PLC control system

(1) For the combustion system of calcining rotary kiln, the size and proportion of the primary damper can be automatically controlled according to the hot air temperature from the furnace; Adjusting the valve and valve simultaneously with coarse adjustment and fine adjustment can avoid the temperature oscillation during the adjustment process.

(2) Equipped with hot/cold starting switch and local/remote ignition functions to adapt to various working conditions.

(3) With hand/self-moving optional on/off. When manual mode is adopted, each execution unit can be started and stopped manually on the control cabinet, and the control valve, small fire gas electric control valve and electric damper can be separately controlled, so as to meet the requirement of manual control of temperature rise during drying kiln.

(4) Purge before ignition and purge after flameout can be realized automatically for each startup or shutdown to ensure safety.

(5) With system safety interlocking protection function. When the gas pressure is ultra-low, the wind pressure is ultra-low, or the induced draft fan stops, or when the gas leakage occurs on site or the burner shuts off, sound and light shall be sent to alarm, and the fuel shall be cut off immediately and the primary and secondary fans shall be kept for purging. There is a special emergency stop button, when pressed immediately cut off the fuel. When the secondary air pressure is very low, sound and light alarm will be issued without stopping.

(6) During the working process of the burner, when the control system detects any conditions that do not meet the requirements of safe combustion, it will immediately conduct safety linkage, cut off the natural gas and purge. The next ignition can only be carried out after troubleshooting.

(7) the DCS control system and the upper machine communication is to rely on up a machine with dry contact and analog signals, including the flameout, low wind pressure, low gas pressure, ignition flame failure, small fire flame, scavenging before and after the scavenging furnace with embers and other rotary kiln parameter overrun, combustion chamber overtemperature switch quantity, and natural gas, air pressure, flow rate signal, analog signals such as the opening of the valve position.

(8) The control loop has a separate manual control function. In case of PLC failure, the burner can also be manually controlled.

First,Boiler combustion transformation of thermal power plant

At present, China's technology and technology cannot achieve the full realization of nuclear power generation, so its main power generation mode is still thermal power plants. In order to solve its environmental pollution problem, it is necessary to apply the low-nitrogen combustion transformation technology accordingly, so that China's thermal power plants power generation on the road of sustainable development. The core of its low-nitrification combustion transformation is to upgrade the traditional combustion mode to the three-dimensional graded combustion mode by using the vertical pulverized coal super-concentration separation technology. In the actual transformation process, the burner in the original boiler needs to be re-improved and rearranged to be a low-nitrogen burner in an overall way, and its pulverized coal nozzles should be changed to an up-down swinging structure and separated vertically to achieve the purpose of improving the heat efficiency of the low-nitrogen burner and reducing NOx emission.

Second, low nitrogen combustion operation optimization of thermal power plant.

After replacing the traditional burner with a low-nitrogen burner, it is necessary to carry out corresponding optimization work, so as to ensure the normal operation of the boiler comprehensively and improve the power generation rate, expand the economic benefits of the thermal power plant, and reduce the gap between steam temperature and smoke temperature on both sides. At present, the commonly used operation optimization measures for low nitrogen combustion in thermal power plants can be roughly divided into adjusting pendulum Angle and burnout wind. Adjust the primary wind, secondary wind and boundary wind; Adjust the oxygen in the furnace; Adjust a few measures such as pulverized coal fineness.

Adjusting the pendulum Angle and burning-out air means that under the condition of high steam temperature, appropriately reducing the burner's pendulum Angle and optimizing the burning-out air can effectively reduce the oxygen content, appropriately increase the upper combustion rate, and significantly improve its low-nitrogen combustion efficiency.

Adjustment of primary air, secondary air and perimeter wind refers to the realization of low oxygen combustion in the main combustion area through the realization of secondary air combination, and the actual adjustment of corresponding parameters, and the more suitable adjustment of secondary air through the actual low-nitrogen combustion situation.

Adjusting the oxygen content in the furnace refers to controlling the oxygen content in the furnace between 2.5% and 3.5%, which can obviously reduce NOx emission and ensure that the boiler can maintain a good working efficiency for a long time.

To adjust the fineness of coal powder is to adjust the separator baffle appropriately, make it smaller, reduce the fineness of coal powder, and finally make the combustion of coal powder more sufficient, which can effectively prevent the overheating of the heating surface due to the low oxygen environment, and improve the safety and stability of its boiler operation.

Cause analysis

(1) The head of the lamp is located outside of the center air gun. Because of the high load of the center air gun, the head of the lamp is in the high temperature area, so the welding seam of the head of the lamp on the lamp is aged, leading to the flame burning from the weld and burning out the head of the lamp.

(2) The burner now in use was designed and manufactured according to the environmental requirements at that time. The central air gun is arranged in the central position of the burner, and the burner itself is composed of a burning path made up of brazing brick and fire path brick, and a burning flame is formed in the burning path.

(3) Due to the high hydrogen content in the fuel (61%), the flame burns faster, so the flame temperature in the central area of the firebrick is very high. Due to the damage or non-solid insulation lining between the firebrick installation and the furnace bottom, the temperature of the firebrick radiates to the furnace,the bottom plate and the upper cylinder of the burner cause the overtemperature of the burner housing.

(4) In the high temperature region at the center of the burner, local high temperature causes N2 and O2 in the air to react to produce a large amount of NOx (NO, NO2); In the fuel gas, the hydrogen content is too high (more than 20%), resulting in the fuel combustion speed is too fast, the flame center temperature is high, so a large amount of NOx is formed, resulting in the flue gas emission cannot meet the emission standards.

The measure

1. Adjustment of burner head size, height and load distribution

Combined with the change of fuel gas composition, the nozzle size of the center gun and side gun of the burner can be changed to reduce the load of the center gun by 20% and reduce the flame height. Adjust the nozzle size of edge gun, so as to adapt to the composition change of fresh air to a certain extent.

2. Burner head coking, partial flame burning, furnace temperature uneven

During the process of fuel gas entering the burner nozzle, affected by the high temperature flame of the surrounding main burner, it may be heated to carbonization and coking inside the burner under the nozzle, gradually causing partial flame burning and uneven furnace temperature. In view of this operation situation, the fuel gas composition should be adjusted, and the fuel gas should be separated from liquid in advance. The gas-liquid separator should be set with liquid level meter to drain out the liquid in time when the liquid phase is generated, so as to prevent the fuel gas from taking liquid.

3. Overtemperature of outer wall of burner

In order to solve the overtemperature phenomenon of the outer wall of the concentrated flame burner, the innovative modification of increasing the height of the small brazier in the central gun of the burner, improving the flame core, reducing heat radiation and avoiding excessive heat radiation to the outer wall of the burner was adopted.

4. The NOx content in the flue gas after combustion exceeds the standard

Adopt graded combustion (multi-gun structure), inside and outside two layer side air gun; Flue gas recycling technology, the change in burner burner brick structure form, will be cut between high ever-burning lamps only design auxiliary air rifle gun and level, the main gun out from the edge of the burner brick, implements the fuel gas classification and by introducing a relatively low temperature of flue gas spray hole high-speed, the burner flame cutting into high area, avoid the generation of high temperature, will be independent of its center point changes to eight small spear, point size by phi 80 changed to phi 34, into the wind form changed to ring into the wind, the evenness of fuel gas and air mixture. Fuel fractional combustion technology arranges fuel gas nozzles in a stepped shape. All the burning air is injected into the center of the burner and passes through the stepped fuel gas nozzles in turn to form several burning areas. Above the nozzle with the lowest position is the primary combustion area. The primary fuel gas is completely burned under the condition of a large amount of excess air, the temperature is not easy to rise, and the nitrogen oxide generated is reduced. The secondary fuel gas nozzle is usually arranged on the outside of the burner brick, and the secondary fuel is injected into the mixed flue gas from the upstream. High speed injection of secondary fuel gas can produce a low pressure zone, will be the furnace in cold sinking of oxygen poor smoke inhalation combustion zone to participate in the combustion, which not only reduces the flame temperature, but also can reduce the oxygen concentration in the combustion zone, thus reducing NOx generation.

Data processing in a power generation system

By intelligently testing and verifying the data generated by the power generation system, optimizing the boiler combustion regulation system has shown the potential to save millions of dollars in fuel costs per year. The thermal power plant data 800 MW rated combustion units are equipped with intelligent control and regulation systems to improve fuel economy. By implementing the boiler burner management system for data processing, power plants can save millions of yuan in costs during the boiler's operating life. The system based on intelligent control can improve combustion efficiency and reduce fuel consumption and cost. The data processing in the power generation system comes from the large amount of real-time data generated during the operation of the boiler and generator. The intelligent control of analyzing and acting on the large amount of data is beyond the capability of operators. An intelligent control electronic system is designed to manage and control the boiler combustion process, reducing deficiencies in manual intervention. Boiler burner automation technologies have been operating for decades, but they still cannot handle the operational data levels generated by combustion systems. However, intelligent control can overcome the challenge of massive data and create an optimized boiler combustion regulation system. How data variables affect boiler output, such as low calorific value, intelligent control must be adapted to maintain the limit level and improve combustion efficiency. Because maintenance, instrument calibration, and fuel change status are ongoing, operators do not work well. The adaptive characteristics of intelligent control systems enable them to deal more effectively with real-time changes in physical parameters such as temperature, fuel supply rate and intake damper position. A change in fuel supply will change the intake damper position almost instantaneously, intelligently adjusting the correct damper position to compensate for the change in fuel supply.

Boiler combustion pollution control

Boiler combustion is itself a polluting process, and environmental laws strictly limit the concentrations of sulfur dioxide, nitrogen oxide and PM2.5 that are released into the atmosphere, and have become increasingly stringent with the development of society. Intelligent control can effectively improve existing boiler designs and pollution reduction technologies, enabling plants to provide heat or electricity at a reasonable cost while complying with environmental regulations. Intelligent control of pollution from coal-fired boilers can be applied at all stages of the combustion process. The choice of fuel for boiler combustion is the first step in reducing flue gas pollutants. For example, natural gas combustion is cleaner than fuel oil, medical waste or biomass and produces the least amount of pollutants in its flue gas. Most domestic boilers cannot choose fuel, and the intelligent control system can adjust the fuel and air volume ratio of each layer of burners according to the industrial analysis of the fuel into the furnace, so as to reduce pollution. Intelligent control of boiler combustion can also reduce the production of nitrogen oxides, the boiler fuel from ignition to burnout each process can be calculated and data analysis to give the most reasonable air ratio. For the flue gas recirculation boiler, through the intelligent control system to adjust the amount of flue gas sent back to the combustion chamber, can better the oxygen content of the empty box air, reduce the core flame temperature.

Reduce slagging tendency of boiler

Intelligent control of boiler combustion air redistribution is achieved by closing the center hood to force more air to the sides, since the boiler combustion has a common bellows and hood in the maximum open state. Intelligent control of combustion balance can minimize the oxygen depletion zone and temperature point in the furnace and effectively reduce the slagging tendency of the boiler. By intelligent control, the feed rate of the pulverizer is improved and the fuel is transferred to the lower burner, which provides more residence time before the boiler burns out, and the flue gas temperature is kept under the ash melting temperature to minimize the possibility of slagging.

Exhaust temperature

From the overall operation of the furnace, the greatest heat loss of the furnace is taken away by the exhaust smoke. If the smoke temperature is reduced, the heat released by the smoke can be effectively reduced, so as to improve the heat efficiency of the furnace. The waste heat recovery system of the device is now equipped with an acoustic ash cleaner. In daily operation, the air preheater is used for the acoustic ash blowing of heat pipe to reduce the ash and scale accumulation of heat pipe and convection pipe and improve the efficiency of the preheater, but the effect on reducing the exhaust temperature is not obvious. During the maintenance shutdown in 2019, in addition to the transformation of the heating furnace burner, the heat pipe of the heating furnace waste heat recovery air preheater will be replaced. After the normal operation of the furnace, the exhaust temperature is 162.9℃, which exceeds the 140℃ specified in the Furnace Pipe Rules. The heat loss of the furnace is calculated as 3068KJ/kg fuel. The main reason for the analysis may be that the baffle of the flue gas direct-discharge duct of the furnace may not be closed properly, and part of the flue gas is pumped back into the air preheater again, resulting in the mismatch of smoke and air volume. According to the actual situation on site, it is planned to remove the original heat pipe preheater and replace a new air preheater at the place where the original heat pipe preheater is to reduce the exhaust temperature of the heating furnace to 110℃. In addition, the natural ventilation burner of F202 in the heating furnace waste heat recovery system is replaced with a forced ventilation burner, and the annular air duct and auxiliary air duct, fast-opening air door and baffle valve are added. The combustion-supporting air entering F202 furnace is introduced into the air preheater and then sent to F202 furnace after preheating. After the modification, the thermal efficiency of the furnace is expected to increase from 90.8% to 92.8%.

Oxygen content

The oxygen content of flue gas directly affects the thermal efficiency and safe and stable operation of heating furnace. The flue gas oxygen content is high, the thermal efficiency is low, the furnace tube is easy to oxidize; The low oxygen content of flue gas makes it easy to cause incomplete combustion. During the thermal efficiency test of the furnace, the oxygen content on-line instrument display data of the furnace are all greater than the oxygen content data of the flue gas inlet of the air preheater, the oxygen content instrument may be installed in an unreasonable position or the test is not accurate. The content of oxygen in flue gas is the main parameter that affects the combustion effect of heating furnace. The inaccurate determination of oxygen content is easy to cause insufficient fuel gas combustion, increase the loss of incomplete combustion, and decrease the thermal efficiency of heating furnace.

Operation management

Improve the operating efficiency of the automatic control system of the heating furnace, strengthen the stable control of various parameters such as the total volume, branch flow and temperature inside the heating furnace, and improve the operating efficiency of the heating furnace. There is one induced draft fan in the hydrogenation unit. Under the current practical situation, the opening degree of the flue damper of three reheating furnaces is optimized, the inlet temperature of the air preheater is controlled well, the service life of the air preheater is improved, and the exhaust temperature of the reheating furnace is reduced. In addition, operators should be regularly trained and tested to improve their operational skills and theoretical level, improve operators' understanding of the field heating furnace system, and enhance their operation guarantee technology.

Retrofit of burner

The boiler originally had 4 layers of 16 blast furnace gas burners, the first and fourth layers of burners were replaced by coke oven gas burners after the transformation. There were 8 burners in two layers, and the gas pipe, corresponding valve instrument accessories, ignition device, local control box and other accessories were replaced accordingly. The second and third layers of blast furnace gas burners were old.

Modification of heating surface

For coke oven gas calorific value is higher, coke oven gas boiler heating surface need less, the existing boiler heating surface is relatively big, will lead to the following conditions: (1) due to the chamber of a stove or furnace heating surface is too big, lead to a stove or furnace outlet flue gas temperature is reduced, superheater heat decreases, superheater steam temperature is lower than the original, can not reach the rated temperature, especially in low load condition is more serious, need to increase the superheater in the heated area. (2) Due to the large sulfur and water content in coke oven gas, too low exhaust temperature will cause serious low-temperature corrosion to the heating surface of the tail. Therefore, it is necessary to reduce the heating surface of the tail coal economizer and increase the exhaust temperature.

Reconnect the gas line

DN800 main pipe of coke oven gas shall be set up from the main network of the north ring of coke oven gas to boiler No. 5, butterfly valve, blind plate valve and corresponding metering device shall be installed, and branch pipe, four-angle pipeline and regulating valve shall be installed according to the design requirements of burner.

Modification effect

(1) After the transformation of coke oven gas, the boiler is in good running condition and all operating parameters meet the requirements, eliminating the adverse effect of high and direct mixing combustion mode of coke oven gas on boiler operation. The smoke exhaust temperature rose from the average 137℃ before the modification to the average 153℃, which greatly reduced the low-temperature corrosion of the heating surface at the end of the boiler.

(2) After the transformation, the surplus of coke oven gas in Xuangang was effectively digested, and the environmental pollution caused by the release of coke oven gas was eliminated.

(3) Reduce the amount of blast furnace gas burning, transfer to other boilers consumption, improve the steam load of other boilers, at the same time, improve the spontaneous electricity.

(4) It solves the bottleneck problem existing in the current all-fired BF gas boiler and can effectively maintain the normal operation of the turbo-blower in the case of the interruption of BF gas, thus creating conditions for the overall stability of Production in Xuangang.

The flame shape

It is a thin disk - shaped flame that extends evenly around the wall or top of the furnace.

structure

It is composed of ejector, head and burner (fire hole).

The working principle

The gas is inhaled by the nozzle for one time, mixed and then discharged through the strip fire hole of the head. The secondary air is inhaled by the negative pressure in the furnace and meets with the gas mixture at the outlet of the fire hole. When the two are mixed, they burn in the brick groove of the burner, forming a flat flame.

The characteristics 

1,Uniform heating to prevent local overheating -- as the flame center is a reflux zone, it has the effect of stabilizing the flame and stirring.

2, the center of the flame is the reflux zone - enhanced combustion, need less excess air - reduce the NOx content in the flue gas.

3, the furnace heating (convection, radiation heat transfer intensifies), and close to the heated parts - heating materials quickly, save gas.

4,Uniform pressure inside the furnace (positive pressure zone around the furnace wall) -- prevent cold air inhalation.

5,High requirements for manufacturing and installation, limited positioning, and not too large thermal load.

The NOx produced during combustion mainly includes fuel type, thermal type and rapid type. As for gas fuel, the NOx produced by gas combustion is mainly of the rapid type and thermal type due to the little nitrogen in the fuel. From the perspective of reducing thermal type and rapid type NOx, the core technology of low nitrogen combustion is to rationally optimize the mixing process of fuel and combustion air and control the local high temperature in the furnace.

At present, low-nitrogen gas burners generally adopt technologies such as graded combustion and thick-light combustion, etc. Although NOx production can be reduced to a certain extent, it cannot meet the existing environmental protection standards [3]. On the basis of the existing technology, the new low-nitrogen gas burner integrates the most advanced ultra-low nitrogen combustion technologies, such as subsonic supermixing and strong and weak cyclone hedging dynamics [4-5] (FIG. 1 -- FIG. 3). On the one hand, fuel and air are fully mixed, local high-temperature zone in the furnace is eliminated, and the residence time of flue gas in the high-temperature zone is reduced. On the other hand, it enhances the combustion stability and provides a favorable guarantee for increasing the flue gas external circulation technology. In order to meet the standard that NOx emission mass concentration of gas boiler is lower than 30 mg/m3, flue gas recirculation technology must be added on the basis of existing low-nitrogen burners to achieve the emission standard of gas boiler. Flue gas recirulation will be low temperature flue gas boiler tail into the combustion air, and fully mixed with the combustion air to participate in combustion, can effectively reduce the volume fraction of oxygen in the combustion air, thus reducing the initial mixing combustion intensity and combustion temperature in the furnace, and finally reduce the furnace thermal NOx generation effect.

Considering the flue gas recirculation effect and the influence of combustion stability, a new type of low nitrogen gas burner design makes the gas fuel in the throat section into plane distribution, combustion flame along the radial and axis from the inner to the outer layers of support, superior combustion stability, and overcome the existing low nitrogen gas burners in after adding flue gas recirculation combustion efficiency is low, the problem of the flame, and can effectively control quality of NOx emission concentration under 30 mg/m3. New type burner with low nitrogen recycling flue gas is mainly in guarantee under the condition of combustion stability, reduce the combustion air oxygen volume fraction, burner combustion intensity decrease throat area, makes the fuel part turned back along the depth of the chamber of a stove or furnace combustion, flame length longer, can make full use of furnace space to reduce the flame temperature, thus inhibiting type thermal NOx formation.

1. Positioning of burner

Many companies use "light column" burners positioning, accurate control, but not easy to operate. It is better to use the position scale to locate on the kiln head section. Generally, it is better to control the position slightly to the right of the X axis of the kiln head section or slightly to the fourth quadrant. In special process conditions can do a little fine tuning.

2. Influence of burner position on kiln conditions

During installation, when the burner is in the horizontal position, the center point and the cross section center point of the kiln are at the same point. Before the end of each overhaul, the position of the burner is corrected and checked more than once. During normal production, the method to determine the correct position of the burner and to adjust the burner is as follows:

Look from the kiln, the shape of the flame should complete strong, lively, not scour kiln skin, also can't top material calcined, outer flame of fire in contact with the material with stove, if the location of the burner is too partial, the flame will flush into the kiln, kiln cylinder local high temperature, reduce the service life of kiln lining, and the calcining zone of the kiln will be backward outspread, furnace thermal system disorder, serious when, soon red kiln feeding. At this point, the burner should be properly adjusted to the direction of the material, so that the flame flame and material contact. If the burner is too close to the material, the flame will support the material, causing the top fire forced burning incomplete coal powder is wrapped by the rolling material, burning with a serious reduction atmosphere, reducing the quality of clinker. The gas with a serious reducing atmosphere is brought into the preheater system to reduce the temperature of the liquid phase of the material, make the preheater system crust or even block, and affect the normal calcining of the kiln. At this time, the burner should be properly adjusted away from the material to make the flame smooth and powerful.

3. Adjustment of normal and abnormal conditions

In normal operation, if the temperature of the kiln firing zone is low, the opening of the inner wind butterfly valve should be increased and the opening of the outer wind butterfly valve should be reduced to shorten the flame and improve the temperature before kiln. When the sintering temperature is too high, it is necessary to open the outer wind butterfly valve and close the inner wind butterfly valve, so as to make the flame elongate, maintain a certain fast turning rate of the kiln, and improve the output and quality of clinker.

If found thick kiln stove or ring, should be disposed in time, otherwise it will affect the yield and quality of clinker, into the furnace burner that outside the wind butterfly valve fully open, endogenous wind butterfly valve is short, the center of butterfly valve will open a big wind, make the flame, burning with ward, improve the body temperature, if found burnt with a flat piece of material, certificate after circle has dropped, the burner all back to the furnace mouth position, outside the wind butterfly valve closed small open degree, endogenous wind butterfly valve open big, center of butterfly valve to close small wind, shorten the flame, improve kiln speed, good control of clinker junction temperature, protect the calcining zone kiln. Because there are a lot of factors, should be according to the kiln type and the structure of the ring, the specific situation analysis, as long as the method is reasonable, it is not difficult to deal with.

Therefore, the method can be used to solve the problem

1. Close all switches without power supply and check the fuse

1. Limit controller TL is turned on for adjustment or update

1. Adjust or update the security controller

1. Control box lock restart (1 second after lock)

1. Disconnect the motor protection (phase loss) and reset the thermal relay

1. Replace the stuck pump after damage

1. Check the connection for electrical connection errors

1. Control box is damaged and replaced

1. Replace the motor controller if it is damaged

1. Motor damage and replacement

1. Photocell short circuit replace the photocell

1. Eliminate the light source or replace the control box when light and simulated flame appear

1. Reset after phase-missing protection connection

1. There is no oil in the oil tank or there is water in the oil tank. Raise the oil level or drain the water

1. Improper adjustment of combustion head and air control valve. See page 5-8

1. Primary solenoid valve or safety solenoid valve has not been opened to check the circuit and replace the solenoid valve

1. The primary nozzle is blocked, dirty or damaged and replaced

1. The ignition electrode is not adjusted or dirty-adjusted or cleaned

1. The electrode is replaced due to the failure of the insulation equipment

1. Damage of high voltage cable or replacement of ground

1. Deformation replacement and protection of high voltage cable due to high temperature

1. Ignition transformer is damaged and replaced

1. Solenoid valve or transformer connection error check

1. Control box is damaged and replaced

1. Pump does not move restart and see the reason for previous immobility

1. The connecting shaft joint is damaged and replaced

1. Inversely connect the inlet and outlet pipelines

1. The pump connection valve is closed and open

1. Dirty filter: pipeline - pump - nozzle cleaning

1. Replace the connection by reversing the motor

Lock within 5 seconds after successful ignition. 1. Photocell or control box damaged and replaced

1. Clean the dirty photocell

1. The first-class hydraulic cylinder is not opened to replace the hydraulic cylinder

Pulsating ignition or ignition instability 1. Incorrect setting of combustion head

1. Dirty electrode or improper position adjustment (see Figure B on page 5)

1. The damper is set incorrectly, and the level 1 wind is too high for adjustment (see Figure D on page 8).

1. Primary nozzle not suitable for boiler or burner adjustment (see table on page 4)

1. First stage nozzle is damaged and replaced

1. The pump pressure is not suitable for adjustment between 10 and 14bar

The control device TR is not closed for adjustment or replacement

1. Control box is damaged and replaced

1. Secondary solenoid valve coil is damaged or solenoid valve is blocked and replaced

The second nozzle is sprayed with oil, but the damper cannot reach the fire position. 

1. Secondary hydraulic cylinder is damaged and replaced

The burner will stop at the stage of fire switching, and the burner will start again. 

1. Clean the dirty photocell

1. Excessive air volume reduction

Abnormal fuel supply 1. Check that oil is supplied to the burner from a tank close to the burner due to the oil supply system or pump

There is water in the tank. Remove the water from the bottom of the pump with other pumps

Pump noise, abnormal movement 1. Inlet pipe intake. The inlet pressure of the oil pump is too high (higher than 35cm hg) to tighten the connection

1. Too large liquid level difference between tank/burner adopts circulating circuit for oil supply

1. Pipe diameter is too small to increase

1. Plug and clean the oil inlet filter

1. Oil inlet valve is closed and open

1. The condensation of paraffin causes the temperature to drop and another light oil is added

After a long time of interruption, the pump does not start. 1. The return pipe is not immersed in the oil, return it to the inlet oil level

1. The inlet gas of the oil system fastens the joint

Pump leakage 1. Leakage from the seal to replace the pump

Smoke - black or white smoke 1. Insufficient air volume adjust the damper according to page 5,8

1. Wrong nozzle type selection or plug replacement

1. Replace or clean the nozzle filter block

1. Wrong adjustment of pump pressure to 10-14bar

1. Keep the fire blade dirty, loose or damaged. Clean, tighten or replace it

1. The furnace exhaust capacity is not large enough to increase

- white smoke 1. Too much air intake adjust the damper according to page 5,8

Dirty burner 1. Replace the dirty nozzle or filter

1. Improper injection amount or Angle of the nozzle refer to the push nozzle, page 4

1. Screw the nozzle loose and tight

1. Clean sundries on fire stabilizers

1. Incorrect combustion head or insufficient air volume adjust according to page 5 to open the damper

1. The length of the combustion head is not suitable for the connection between boiler and boiler plant

1. Burner nozzle does not spray oil

The possible causes are oil supply pipeline blockage, oil pump not pumping, oil supply pipeline vacuum leakage, etc. Remove the high pressure discharge pipe to check the oil condition of the oil pump. When pumping oil normally, the oil column should be ejected outward. There is another reason why the nozzle does not spray oil, that is, the oil solenoid valve is not energized. When the oil break solenoid valve loses power, even if the oil pump is in normal operation, the high-pressure end will not supply oil to the fuel injection nozzle. Only after the controller makes the oil break solenoid valve electrified can diesel fuel be allowed to blow out, the purpose of which is to prevent the original accumulation of diesel fuel in the furnace from deflating when it meets an open fire. Under normal circumstances, the burner carries out a pre-blow air to clean the combustion chamber of residual diesel oil, and then fuel injection ignition. In the pre-blowing stage, although the oil pump motor is running, the oil cut-off solenoid valve is not energized, and the high-pressure diesel oil pumped by the oil cut-off solenoid valve cannot reach the fuel injection nozzle.

2. No ignition high pressure

When the ignition transformer is energized, a high voltage of about 8KV is generated. This voltage breaks through the electrode gap, generating a strong spark that ignites the diesel oil mist. When the flame burns stably, the spark ignition is no longer needed, and the flame sensor sends the flame status information to the controller to stop the work of the ignition transformer. First, the ignition transformer is not energized (it may be due to poor contact of the power supply line or the relay in the controller). The other is that the insulation between the two thermal electrodes is poor due to carbon deposition, and the high voltage is leaked, so there is no discharge spark. The distance between the ignition electrodes should be about 3mm, and the distance between the ignition electrodes and the front face of the nozzle should be about 5-7mm. The two electrodes must be well insulated.

3. Low pressure of burner oil pump

After long-term use and wear of the oil pump, its maximum pressure will gradually decrease, resulting in bad oil injection atomization and difficulty in ignition. After fire, there will be a large number of smoke and unstable flame, and it is of no help to adjust the pressure of the oil pump. The aging of the nozzle results in a similar situation of poor atomization.

Look: that is, by observing the surface phenomena, so as to find and troubleshoot. Such as indicator light, alarm light, motor steering, electric eye, electrode position, damper and combustion head position, servo motor action, chimney installation, tubing diameter, wiring, thermal relay, flame color, smoke color, oil pressure gauge, gas pressure gauge, etc.

Listen: Use the sound to determine the fault position of the burner. For example, the sound of electrode rod discharge, ignition and deflagration, oil pump, motor, program controller running, fire switching, solenoid valve switch, etc.

Q: That is, ask the user. Such as wire modification, voltage fluctuation, temperature setting, fuel replacement, oil line cleaning, failure time, failure regularity, the length of service time, the recent self-inspection position and process.

Repair: according to the above three points and combined with the working principle of the burner to determine the fault location and repair.