Questions&Answers

Burner rotor scale is composed of rotor, mounting frame, transmission device, weight measuring system and soft joint. The rotor is mounted in an explosion-proof housing together with the sealing plate. The whole burner rotor scale shell and the rotor transmission device are suspended in a frame as a whole. There are two fixed rolling bearing pedestals suspended from the frame to support the burner rotor scales. The third suspension is connected to a weighing device with a load sensor. The feed pipe, discharge pipe and compressed air pipe of the burner rotor balance are provided with soft joints connected with the corresponding parts.

The feeding process of the burner rotor scale is: pulverized coal is directly discharged from the pulverized coal silo through the sliding gate, and enters the rotor part through the soft joint at the entrance. The pulverized coal is taken away by the compartment of the rotor, rotated 225°, and reaches the discharge area. The air of the bottom compressed air pipe blows the pulverized coal in and out of the material port and sends it to the burner.

The rotor shell is made of ductile iron and is divided into two parts: upper shell and lower shell. The upper shell is provided with a feed port and a discharge port, and the lower shell is provided with an air inlet and a flange for the butt of the transmission device. The rotor is cast iron composed of two rows of interlocking small compartments connected to the drive shaft through the central hub. On the upper and lower sides of the rotor, there are two sealing plates respectively. The sealing plate is a special casting. The specific clearance between the rotor and the sealing plate can be adjusted by special screws in the housing. The whole rotor and the sealing plate are installed in the shell of the burner rotor scale. The explosion-proof design can withstand the sudden pressure of 1 Mpa. The reducer of the transmission device is connected with the lower shell of the burner rotor scale by a flange. The DC speed regulating motor is transferred to the reducer through the toothed belt. The output shaft of the reducer is connected with the shaft of the rotor. The digital speed measuring motor is connected with the driving device, and the rotor speed is measured by the contactless sensor. The weight measuring system is composed of load sensor balance and damping device.

To ensure reduction and reducing and the bias stability of heavy equipment, in order to make the transmission power consumption and low degree of wear of the internal parts, Pfister company to solve some special technical problems, which is used for the hydrostatic bearing system of balance of the rotor of the burner and load with a pneumatic control device internal seal on the pipeline to burner, using method of the pressure vessel formation arc small air barrier to feed, with the exhaust pipe cleaning nozzle arc storehouse.

In the production process of cement industry, the problem of erosion and wear of the inner wall of the inlet and outlet of the pulverized coal rotor scale of the burner is often encountered. Under normal conditions, most enterprises repair or even directly scrap and replace by surfacing abrasion resistant electrode. Generally speaking, the surfacing effect is not ideal, and the cost of scrap replacement of imported parts is relatively high. Therefore, the wear of pulverized coal rotor scales of the burner, which is washed by pulverized coal for a long time, has also become an equipment problem affecting the continuous and normal production of cement enterprises. Polymer composite material technology relies on the structure of the material itself to bring strong adhesion, high wear resistance, impact and erosion resistance and other properties to fully realize the rapid operation of the site and repair after the completion of the use effect.

Burner pulverized coal rotor scale feed port erosion wear repair

In the working process of pulverized coal burner rotor scale, the inlet part bears the serious erosion and wear process. The medium environment of this part is very bad, which often causes the wear of the inlet. When serious, it can cause shell perforation and cause significant damage to the equipment. This kind of problem exists in the use of equipment for a long time, and it is difficult to solve by using the conventional general repair method, the replacement cost is high, and the enterprise increases a lot of downtime, which seriously affects the normal production schedule. This problem can be solved by the excellent wear resistance and good plasticity of the technical products.

Burner pulverized coal rotor scale discharge port erosion wear repair

In the working process of pulverized coal burner rotor scale, the outlet part bears the serious erosion and wear process. The medium environment of this part is very bad, which often causes the wear of the outlet. When serious, it can cause shell perforation and cause significant damage to the equipment. This kind of problem exists in the use of equipment for a long time, and it is difficult to solve by using the conventional general repair method, the replacement cost is high, and the enterprise increases a lot of downtime, which seriously affects the normal production schedule. This problem can be solved by the excellent wear resistance and good plasticity of the technical products.

The shell part of the pulverized coal burner rotor scale bears serious erosion and wear process in the working process. The medium environment of the part is very bad, and serious erosion and wear often occur, which causes significant damage to the equipment and affects the measuring accuracy of the rotor scale. This kind of problem exists in the use of equipment for a long time, and it is difficult to solve by using the conventional general repair method, the replacement cost is high, and the enterprise increases a lot of downtime, which seriously affects the normal production schedule. This problem can be solved by the excellent wear resistance and good plasticity of the technical products.

1. optimize the wind pressure set value

Usually, an initial value of the primary wind pressure setting value should be given preliminarily before the boiler is officially started. When the boiler is officially started, with the increase of unit load, the primary air volume will also increase, and the primary air duct pressure will also change. When the opening of the hot air baffle in the pulverizer system is less than 50%, the primary air pressure setting value can be reduced appropriately at this time. When the > is 80%, it is necessary to increase the wind pressure set value.

2. Adjust the burner to swing the nozzle properly

By adjusting the position of the burner nozzle, the purpose of automatic value setting is achieved. First of all, the nozzle Angle can be adjusted according to the internal flue gas temperature of the boiler. When the Angle is large, it will increase the burden of solid combustion and cause greater heat loss. However, a smaller inclination will result in a larger amount of residue accumulation, so it is necessary to find the best inclination by adhering to the principle of scientific adjustment. Secondly, the rotation rate of the burner nozzle can be adjusted to realize the synchronous operation of the air flow and avoid the uneven distribution of the air structure inside the boiler. Finally, the position of the burner nozzle can also be placed in accordance with the law of "upper group lower group upper group", so that the heat load of the main combustion area is reduced.

3. Scientific arrangement of cyclone burner

The cyclone burner is actually a new type of boiler burner, which is mainly composed of secondary air duct, primary air duct and cyclone. In order to ensure the timeliness of pulverized coal boiler combustion, the swirl burner can be optimized according to the following contents:

(1) The corresponding primary wind speed is designed for different kinds of coal to avoid the occurrence of local backflow area inside, which affects the combustion quality.

(2) The swirl intensity can be adjusted. When the swirl intensity of the swirl burner in the boiler is weakened, it will have an impact on the combustion degree, so it needs to be adjusted appropriately according to the actual situation.

4. Determine the secondary air damper setting value

When optimizing the automatic setting value, it is necessary to further determine the secondary air small damper setting value. The secondary air small damper plays an important role in pulverized coal boiler, which can effectively reduce the influence caused by the obstruction to the operation of the coal mill. When optimizing it, it can be carried out from the following two aspects:

(1) the adaptability of the burner in pulverized coal boiler can be appropriately enhanced, and the internal combustion effect can be better by using the way of circumferential wind. On the one hand, the perimeter wind can scientifically control the combustion rate of high-quality bituminous coal, so that it will not burn all the fuel prematurely, resulting in a shorter combustion time of the boiler. Therefore, if the quality of bituminous coal used in pulverized coal boilers is high, the circumferential air volume can be appropriately increased; On the other hand, the circumferential wind can reduce the concentration of pulverized coal. Therefore, for anthracite or coal with poor volatility, the circumferential air volume should be lowered to promote the development of coal combustion in the boiler to stabilize.

(2) the combustion of pulverized coal boiler needs reasonable use of auxiliary wind, which can adjust the wind direction in the boiler. When the momentum in the boiler is relatively small, it is not conducive to the smooth combustion of coal. On the contrary, the pulverized coal in the boiler will be separated from it, which affects the actual combustion quality and leads to more residue.

1. Optimization and adjustment of flue gas

Under the condition of satisfying the performance guarantee of NOx removal rate and ammonia escape rate, the SCR system is designed to have the lowest continuous operation temperature of 315℃ and the highest continuous operation temperature of 420℃. Ammonia spraying should be stopped when SCR reactor inlet is below 315℃. The pre-smoke temperature of SCR reactor was controlled to be less than 450℃.

2. Optimize and adjust the amount of ammonia injection

According to the boiler load, fuel amount, SCR inlet NO concentration and outlet NO concentration to adjust the amount of ammonia injection. Influenced by the uneven concentration distribution in the ammonia injection reaction zone and the poor characteristics of the ammonia injection valve, when the load change is relatively large, the regulator timely manually interferes with the operation of the ammonia injection valve and adjusts the adjustment range according to the operation situation of the ammonia injection valve and the NOx concentration value at the SCR reactor outlet. If the differential pressure at the SCR inlet and outlet exceeds 750Pa, the soot blowing frequency should be increased until the differential pressure is normal, otherwise ammonia spraying should be stopped.

3. Optimization and adjustment of dilution air flow

The dilution air flow rate is set according to the maximum ammonia injection amount corresponding to the denitrification efficiency, so that the ammonia volume concentration in the ammonia/air mixture is less than 5%. In the ammonia air mixer, ammonia and air should be evenly mixed and maintained at a certain pressure. The dilution air volume on each side shall not be less than 3200Nm3/h.

4. Optimization of operation mode of pulverizing system

When the unit is running normally, keep the lower pulverizing system running for a long time. The NOx concentration at the SCR inlet of the lower mill was lower than that of the upper mill. Under the condition of ensuring the normal operation of the coal mill, and the high melting point of coal ash, it is not easy to reduce the primary air pressure when the burner mouth cokes, which can effectively reduce the concentration of nitrogen oxides at the denitrification SCR inlet.

5. Adjustment and optimization of burnout air opening

In order to adapt to the load change, the opening of SOFA wind baffle should be adjusted in time to ensure that the high temperature and low oxygen in the burning area, the low temperature and rich oxygen in the burning area, and the generation of NOx should be reduced. Through the burnout air optimization adjustment test, SOFA damper opening (H layer 20%,I layer, G layer opening are in 70%) and fully closed G layer SOFA damper, fully open I, H layer SOFA damper, denitrification device spraying ammonia reduced 14.13kg/ H. When the load changes, adjust the opening of SOFA wind baffle in time according to the NOx concentration of SCR inlet.

6. Adjustment and optimization of oxygen capacity

A slightly higher oxygen content at low load is beneficial to the stability of boiler combustion, while a slightly lower oxygen content at high load is beneficial to the reduction of fan power consumption. Under the premise of ensuring the stability of boiler combustion, maintaining the appropriate oxygen amount is beneficial to reduce the generation of NOx. Oxygen content above 500MW load was maintained at about 3.0%, 400 ~500MW at about 3.5%, 350 ~450MW at 4.0%, and 300MW at about 4.5%.

7. Adjustment and optimization of soot blowing

The denitration area uses the sonic soot blower to blow soot regularly, and the steam soot blower is used as the standby. The test shows that in order to ensure the best soot blowing effect in the denitrification area, the following soot blowing operation mode is developed: 2 sonic soot blowers in the same layer are set as one group, and 2 soot blowers on both sides of the reactor are set as one group, and the soot cleaning is performed simultaneously in the group. Each group of acoustic soot blowers will sound 10s when blowing soot, and the next group will sound 40s.

8. Strictly control the quality of coal

Affected by the tight supply of coal market, the power plant takes the way of mixing and burning to reduce the cost of power generation. Most of the time, the coal source is unstable, can not meet the requirements of the design of coal. It is found through the test that the coal ash content in the furnace is high, the dust content of the flue gas is increased, and the maintenance of the same load will increase the amount of ammonia injection, which is not conducive to the control of nitrogen oxides. Therefore, the coal ash content should be strictly controlled and not exceed the design value as far as possible.

The formation mechanism of NOx

The primary air is mixed with the gas, ignited and ejected, and the secondary high-speed airflow coils the surrounding furnace gas back flow, so that the oxygen concentration in the flame combustion area is reduced, and the oxygen concentration of 2% ~ 15% is obtained, forming oxygen-poor combustion, and the production of NO is reduced.

Air passes into the combustion area twice, so that the whole combustion process is divided into two stages, avoiding excessive concentration of high temperature area, and the temperature field in the furnace is more uniform. In high temperature regenerative combustion system, smoke and air switch device is needed, thus reversing valve is the key equipment of the system if the by pass valve, the system has a pair of high temperature regenerative combustion devices will need 4 sets of switch valve, and USES the directional control valve, the system in high temperature regenerative combustion device is only need a switch valve, cost can be greatly, reduce the reversing control in general is given priority to with when reversing, but when overtemperature exhaust system must have at the same time to enforce the function of reversing reversing valve commutation time by time and temperature of master-slave control, i.e., according to the timing, but at the same time, when the regenerator flue gas temperature more than set set, The control system will automatically alarm and control the reversing valve to force reversing according to the temperature signal.

the furnace pressure control in the combustion process

In the process of periodic switching of combustion/exhaust in regenerative combustion system, the furnace pressure will also change periodically, but the change of furnace pressure will obviously lag behind the switching of combustion system. The disturbance to the control system during periodic reversing is the difference between regenerative furnace and conventional furnace. But due to the interference is foreseeable interference, control system in the automatic control mode, the system can be used "shock" the method of interference filter system, to stabilize the combustion and to prevent the cold wind, absorption system should be set inside the furnace pressure in the 0 to 50 pa micro positive pressure condition, the computer system should be able to control the adjustment of the machine top butterfly valve opening automatically track the set value, guarantee within the scope of furnace pressure has been set.

1.Before the installation of oil-gas boilers, relevant units should determine safe and reliable gas supply methods in accordance with national standards or industrial standards such as GB50028 "Urban Gas Design Code". The pressure vessels, pressure pipes and gas cylinders used in the gas supply system should meet the requirements of relevant safety technical specifications and standards for special equipment.

2.The configuration of the burner must meet the technical requirements of the burner configuration specified in the technical data of the boiler factory. 3. Burners shall meet the requirements of safety technical specifications and standards such as Boiler Safety Technical Supervision Regulations, and oil and gas burners shall pass type tests.

3.The boiler user shall not modify and unlist the operation control program of the burner without permission.

4.The boiler user shall conduct daily inspection of the burner, boiler safety accessories and safety interlocking devices in accordance with the requirements of relevant safety technical specifications for boilers, and make inspection records.

5.When the burner needs to be repaired, the boiler user shall ask the manufacturer of the burner or its authorized unit to do so. 7. After the completion of the installation of new boilers, the system commissioning shall be completed jointly by the boiler user and the boiler erection unit or the boiler manufacturing enterprise. During the commissioning, boiler operators with corresponding qualifications shall carry out the boiler operation.

6.The technical personnel of the boiler manufacturing unit or its authorized unit shall provide on-site guidance when the burner is to be debuged6. The technical personnel of the boiler manufacturing unit or its authorized unit shall provide on-site guidance when the burner is to be debuged7.

7.During the commissioning of the boiler system and burner, the safety management organization of the boiler user unit shall ensure that irrelevant personnel shall not gather near the boiler.

8.The transformation and replacement of the burner shall follow the relevant construction notification procedures in accordance with the provisions of the boiler repair. The burner manufacturer or its authorized unit shall be responsible for the transformation, replacement and commissioning of the boiler burner, and the boiler user shall cooperate with the work. After the transformation and replacement of the burner, the user shall conduct self-inspection of the safety accessories such as the boiler safety valve and safety interlock protection device, and form self-inspection records.

9.Any transformation, repair and replacement of the burner shall not reduce the safety performance and energy efficiency index of the boiler and shall meet the environmental protection requirements.

10.Please read the attached technical data carefully before commissioning, ignition and use of boilers and burners, and carry out the work in strict accordance with the operating procedures.

11.When the burner is working, abnormal movement, abnormal sound or other abnormal conditions, it should stop running in time, find the reason, and continue to use after troubleshooting.

Commissioning of gas supply pipeline

After the burner is installed, it is necessary to connect it to the air supply pipe network. The diameter of the gas supply pipe should meet the requirements of air supply, and the pressure loss should not exceed 5mbar. For the burner, when the diameter of the gas supply pipe is 1.5 or 40mm, the connection of the gas supply pipe of the burner should leave enough space to ensure the opening of the burner, so as to facilitate future maintenance work. Install the following components in sequence: 1. Ball valve; 2. Filter; (3A. Pressure regulating valve); 4. Double solenoid valve. If the gas pressure is higher than 500mbar, it is necessary to install a voltage regulator at the front of the pressure regulator valve to ensure that the gas pressure at the front of the pressure regulator valve is between 300-500mbar.

The following points should be noted when installing the components:

a.In order to avoid the gas pressure dropping too much when the burner is working, the distance between the pressure stabilizer valve and the double solenoid valve should not be more than 1.5 meters. The double solenoid valve is as close to the burner as possible, and the diameter of the pipe should not be less than 40mm.

b.All parts must be installed horizontally. If the double solenoid valve and the pressure stabilizer valve are installed vertically, the resistance of these parts will be increased.

c.Air tightness should be checked after all pipes are connected.

the inspection work before the start

a.Check whether the cables and wires are properly connected; Check the supply voltage, 380-400VAC, check all motor steering; Check whether each instrument works normally.

b.Disconnect the servo motor and check whether the damper mechanism and gas butterfly valve are flexible.

c.Check whether the photoelectric eye works normally. Check air tightness of heat conducting oil pipeline.

d.Start the heat conduction oil circulating pump, add the heat conduction oil of appropriate specifications as required until the oil shortage indicator is extinguished, check whether there is leakage in the heat conduction oil pipeline, and tighten it if necessary.

Winter heating is an important part of college logistics. Especially in northern colleges and universities, the quality of winter heating is one of the important indicators to assess the level of logistics service. High school is a densely populated area, and its campus heating buildings include student dormitories, classrooms, offices, family buildings and other categories, which consume a lot of energy. Due to the lack of unified planning of city heating, most colleges and universities in northern China still adopt the mode of boiler self-heating.

1.Overall replacement of the boiler

Replaced the original coal burning boiler and gas boiler as a whole for the low nitrogen full premixed condensing boiler, energy saving, environmental protection, can fundamentally solve the problem of boiler emissions levels, a new type of boiler nox emissions are less than 30 milligram, meet the requirements of national low nitrogen transformation, because for one-piece replacement equipment at the same time, the runtime components compatibility is good, high thermal efficiency as a whole. The disadvantage of this method is that the boiler belongs to special equipment, and there are still gas hazard sources in the university after replacing the boiler. Because the boiler still exists, it will occupy a certain campus area, and the overall replacement of the boiler needs a large amount of money.

2.Replace the burner

On the basis of retaining the main body of the original boiler, the burner is replaced, and the low nitrogen emission is realized by replacing the burner. The replacement of the burner is cheaper than the replacement of the boiler, but the transformation effect of the replacement of the burner is not as good as the overall replacement of the boiler, and the nitrogen oxide emission is usually about 30-80 mg after the transformation. Because the burner belongs to the afteraddition equipment, there is a matching problem between the burner and the original boiler body, and there are some hidden dangers in operation.

3.Access to municipal heating pipe network

With the increasing thermal capacity of thermal power plants and heating plants, the coverage of urban heat network is gradually extended to the vicinity of colleges and universities. Municipal heating quality is high. After the university is connected to the municipal government, it will provide heating according to the municipal high standard, which can improve the campus environment, cancel the original boiler in the campus, and reduce the transformation of the heat source equipment in the future. At the same time, the boiler room can be vacated to improve the use efficiency of the property. However, colleges and universities have weakened their control over heating. In the future, the increase or decrease of heating area, adjustment of heating time and heating charge should be negotiated with the heating group. Pipeline and equipment need to be modified according to municipal standards, and the investment is high.

4.Replace other clean energy heating equipment

Clean energy, also known as green energy, will not directly produce environmental pollution. At the same time, in low temperature environment, clean energy can also achieve high efficiency heating, such as air source heat pump using the effect of two-stage compression technology. But at present the scale of clean energy should not be too large. Due to the high outlet temperature of the original boiler, the design of the main pipe is smaller, and the outlet temperature of the heat pump unit is lower, the heating scale is too large, it is likely to appear temperature failure, the host often reported failure and many other problems.

If gas is selected, the gas leakage detection device works to detect whether the gas pressure is normal and whether there is gas leakage. If it is normal (if the fuel is diesel, this detection process is not available), then the next step is to switch to the combustion controller. Before the ignition of a stove or furnace purging 36 seconds, if after the purge air pressure switch check enough pressure, servo motor to the ignition position - CAM Ⅴ set position, the ignition transformer energizing, spark ignition electrode, and a double solenoid valve is opened entirely (if the fuel is diesel, the level of electromagnetic valve and solenoid valve open), fuel mixing head, mixed with the air fan sent, ignition burning.

After 2-3 seconds, the ignition transformer stops working, and the photoelectric eye detects the flame signal. If the flame signal is normal, the controller will supply power to the servo motor, turn to the setting position of Cam II, and work with low fire. If the selector switch to allow the fire, and two temperature controller allows, the servo motor to continue running (if the fuel is diesel, the transfer to the CAM Ⅰ Settings are opened at the location of the secondary electromagnetic valve,) to the CAM Ⅱ II set position, the fire work.

If fuel is selected, allow the knob to close at full load and start the burner. By adjusting the throttle lever, after make the burner ignition, damper at about 10%, the status of flame and gas color, if gas is white smoke, the damper is larger, the appropriate measures to reduce CAM, if gas is black smoke, the small air door, need to appropriately increase the CAM (2), until the burner flame bright, exhaust almost no color.

Turn the full load permit knob on, start the burner, and wait until the burner is turned to the fire. Adjust the air door adjusting steel belt, so that the size of the air door opening should be about 70-80%. Then observe the exhaust gas and flame state, if the exhaust gas is white smoke, the damper is larger, it is necessary to appropriately reduce the CAM, or reduce the position of the steel belt, if the exhaust gas is black smoke, the damper is smaller, it is necessary to appropriately increase the CAM, or increase the position of the steel belt. Until the burner flame is bright and the exhaust gas is basically colorless.

1.The capitalization and marketization of enterprises are effective

Industrial boiler enterprises in shaanxi construction jinniu, China Nuclear Power and a few other enterprises are still state-owned, the rest of the enterprises are private enterprises. The transformation of corporate identity creates conditions for the entry of capital. With the further development of the capital market and the need of enterprise development, the capitalization of some boiler enterprises has been completed, and Huaguang, Suzhou Hailu, Hangpan and Chuanrun shares have been listed successively. Recently, Bosch Thermal acquired Wuhan Tianyuan, China Building Materials Holding Company Nantong Wanda, Disen purchased Changzhou Boiler and so on. There are reasons to believe that changes in ownership will be easier and more frequent in the future. The channel that foreign capital enters boiler enterprise of our country will be more unblocked, the pace also will be faster. But followed is the enterprise talented person especially the backbone talented person's flow frequently intensifies.

2.Industry concentration has been improved

Due to the industrial boiler industry manufacturers too many, the products are similar, enterprises due to different products and present different degrees of competition, the competition of conventional products is relatively fierce, some enterprises regardless of the cost of the market, increase production does not increase income phenomenon still exists to a certain extent. But with the gradual rationalization of the competition rules, through the competition make the industry concentration and product brand effect has a certain degree of increase, and form a batch of products of famous enterprises, such as oil and gas in furnace, double liang boiler co., LTD in jiangsu, zhejiang, boiler co., LTD., anyang party fast, zhejiang force gathered all see, the director of the company; In biomass, garbage power boiler, Jiangxijiang Union, Nantong Wanda and other leading; In terms of waste heat utilization, due to different service industries, relevant enterprises have different characteristics. Boiler enterprises have formed their own leading products or main businesses, such as Hangzhou-Boiler Industry, Sea-Land Heavy Industries, etc. What all these characteristic enterprises have in common is single-mindedness, professionalism and persistence, while others are large and small and complete.

3.The degree of overcapacity is increasing

In the future, the degree of over-capacity of a-class boilers will be further aggravated, and many enterprises will not last long. Compared with the industrial boiler, its capacity is more difficult to resolve (difficult to exit), it is worth noting that the three power are all the same to expand the industrial boiler market, success or failure only know their own.

1. Chemical composition analysis

In order to find out the cause of corrosion cracking of the stainless steel nozzles of the effective boiler gas burner, it is necessary to analyze the chemical composition of the nozzles with the problems. In the actual testing process, the inspectors should strictly follow the chemical testing standards and obtain the accurate chemical composition of the nozzle by using the fixed full-spectrum direct reading spectrometer. By analyzing the chemical results, we know that the chemical material of the nozzle conforms to the initial standard.

2. Mechanical performance test

In the process of detecting the stainless steel nozzle of boiler gas burner, it is necessary to carry out the mechanical property test of the stainless steel nozzle. Before the test, according to the test specifications, the test personnel to the stainless steel nozzle bend material for tensile test, its tensile strength and normal temperature yield strength meet the use standard, in the occurrence of corrosion and fracture of the bend test, the bend elongation is far lower than the normal value; After the end of the tensile test, the stainless steel nozzle elbow material did not appear necking, and the crack area showed the characteristics of brittle fracture.

3. Metallographic observation

The inspector shall grind, polish and corrode the elbow material at the cracked location in Figure 1, and then place it under the observation mirror to find the presence of coking attachment and carburizing layer in the elbow in the cracked area. By increasing the microscope magnification to improve the observation coefficient, it can be found that the coking attachment inside the elbow presents a block shape and exists in a continuous network, and the coking attachment far away from the inside of the elbow mainly exists in a broken chain, and the carburizing layer appears a shrinking trend; There are a lot of carbides in the coking attachment, as shown in FIG. 3. Through careful observation, it can be known that the more close to the inside of the elbow carbide material content is higher, the depth of its internal carburizing layer compared to the external carburizing layer thickness decreased, the number of grain boundary material. After sampling and observing the elbow with severe corrosion in FIG. 2, the outside of the elbow is first ground and polished, and then examined through a microscope. It can be seen that the grain boundary in the severely corroded area of the elbow has a great degree of oxidation, and a large number of carbides appear inside. The shape of the area near the inside of the elbow is similar and the oxidation degree is less.

4. SEM morphology observation and energy spectrum analysis

In order to get more accurate reasons for corrosion cracking of stainless steel nozzles of boiler gas burner, the inspectors should also observe the SEM morphology of the bends with corrosion conditions, so as to get accurate reasons. In the actual operation, the inspector needs to sample the elbow with serious corrosion problems first, and then treat it. After observation by electron microscope, it will be found that there are more cracks and voids in the elbow. By analyzing the carbide precipitation phase and austenite collectivity, it can be found that the permeable layer of elbow pipe is mainly composed of various elements.

1.Maintenance and treatment of burner ignition fault

If frequent ignition failures occur during the operation of the burner, the maintenance personnel should consider whether there is a blockage of the tubing. If it is found that the oil pipeline is indeed blocked after on-site inspection, the properties and characteristics of oil raw materials should be analyzed, and then the oil viscosity in the pipeline should be reduced to the normal level by means of oil replacement, heating and catalysis, so as to realize the unobstructed protection of oil pipeline. In addition, the electrode contact fault of the burner nozzle may also lead to the ignition failure of the burner. Therefore, the maintenance personnel should also be in the utility meter support, the nozzle of the combustion gun ignition test, and then implement a reasonable parameter adjustment, the distance between the nozzle and the ignition electrode control in 4 ~ 6mm.

If the burner goes out after ignition during operation, the maintenance personnel should check the filter to see if there is too much sediment in the internal environment of the filter, and then clean it through compressed air. At the same time, if the photocell is covered with a thick dust layer, the transmission stability of its optical signal will be affected, so that the remote control system will produce automatic oil-cutting action, and then the flame will be extinguished due to the lack of oil support. In this issue, maintenance personnel should not only do a good job of the photocell and the surrounding equipment environment clean, but also through the welding technology, the photoelectric cell's circuit connection quality optimization adjustment.

2.Maintenance and treatment of burner flame quality problems

The flame quality problems of burners used in steam injection boilers are mainly divided into three categories: flame combustion is not strong, unstable and not complete. Faced with the problem of weak flame burning, the maintenance personnel should check the operating quality of fuel pump to determine the continuous supply level of oil raw materials. At this point, if it is found that the fuel pump aging is more serious, the oil flow level is low, should be implemented in a timely manner to replace, clean and other treatment means, so as to ensure that the burner flame maintain sufficient fuel support; Facing the problem of unstable flame combustion, the maintenance personnel should conduct quality inspection from two angles of oil and air distributor.

On the one hand, the water content of the current oil should be analyzed, and appropriate dehydration treatment should be carried out. On the other hand, the operation parameters of the air distributor should be dynamically tested to check the stability of its wind pressure supply and adjust the guide vane and regulating ring accordingly; Faced with the problem of incomplete flame combustion, maintenance personnel should be committed to improving the proportion of air oil in the internal environment of the steam injection boiler, so as to provide more adequate oxygen support for oil combustion, so as to ensure the continuity of flame combustion, improve the economic application efficiency of the burner.