Accident and Safety Technology Analysis and Repair of Air Compressor Broken Shaft Accidents of Japanese Acid Air Separation Center Wang Yawei Wuyuan Iron and Steel Company Power Plant, Loudi City, Hunan Province, is the process of dismantling the air compressor broken shaft accident and the disintegration inspection of Japan The situation was comprehensively introduced to analyze the cause of the accident and the process of breaking the shaft.
Finally, the localization and repair process of this air compressor and the operation after the transformation are introduced in detail.
Table Keywords Air Compressor Broken Shaft Semi-open Impeller Rotor Clearance Matching Repair Instrument Kw Air Compressor Introduction Air Compressor is a supporting air compressor for air separation equipment introduced from Japan Acid Company. It is broadcasted by Ishikawajima. (Manufactured two-axis semi-open impeller three-stage centrifugal compressor, put into operation in the month.
The technical parameters are as follows: the speed of the air volume and the motor and the year and month. After the air compressor of the Shaogang air separation unit is shut down, we will use this air compressor (hereinafter referred to as the air compressor) and the other two space-time sub-equipment devices. The air compressor is connected to the grid to jointly supply air to the air separation equipment.
At the beginning of the operation of this air compressor, the vibration value of the shaft is about m, and the displacement is much higher than the rated value. (28 expansion to the maximum of 35 blades. Accident process and damage. The air compressor makes an abnormal noise during operation. The shaft vibration value exceeds the spelling m alarm, and the vent valve automatically opens and vents.
The operator did not find any other problems after preliminary inspection. Due to the urgent need for resumption of production, no further inspection could be carried out.
Thereafter, the value of the shaft vibration during the operation of this air compressor rises to a square m and fluctuates frequently.
The low-level and continuous abnormal sound of the secondary volute exhaust pipe and the cooler in the moon air compressor, and the vibration value of the secondary shaft suddenly rises from the mixing m to the 45-m mixing m alarm, and the m interlocking stop The production of oxygen is forced to stop the inspection immediately, and only a special person can be dispatched to monitor the operation.
At the time, the air compressor suddenly smoked and made a sharp noise, and the surveillance personnel immediately took emergency stop measures.
The air compressor is dismantled and the damage is as follows: The first and second low speed rotor gear shafts are twisted from the root of the secondary impeller.
(2) The apex angle of the two blades on the intake side of the two-stage semi-open impeller is broken. The resistance angle of the two c5 has been broken by the impeller and enters the secondary cooler with the airflow.
There is obvious ash accumulation on the blade fracture of the impeller.
The exhaust side (blade outer edge) of all the blades is ground to a deep, triangular-shaped gap and is bluish.
The outer circumference of the impeller rear end cap is about to be severely worn.
(3) The outer impeller of the first-stage impeller wears, the deepest point in the diameter direction.) After the secondary impeller breaks the shaft, the impellers of each stage move toward the air inlet, causing the front end surface of the blade to rub against the inlet end of the volute. The secondary wear is severe and the third grade is lighter.
(5) All oil seals and gas seals, as well as primary and secondary bearings, are damaged.
(6) The deflector in the elbow of the secondary intake pipe is severely corroded, and the outer edge of the elbow has a triangular steel plate with a side length of 45 thick.
The piece of the detached steel plate was broken by the secondary impeller and entered the secondary outlet cooler. It was found to be rusty. The intercooler primary and secondary intake manifolds and volutes are severely corroded.
The air compressor has been officially put into operation since the year of the year until the accident occurs. The intermediate cooler has never been subjected to core inspection and cleaning anti-corrosion work. Therefore, the weight of the scale removed from the severely rusted cooler is more than falling off. Part of the rust is carried away by the airflow, and another part is deposited at the bottom of the cooler and plugs the drain nozzle, making it difficult for the condensate in the cooler to drain from the trap and can only be carried to the next stage with the gas flow.
Analysis of the cause of the broken shaft In the first phase of the air compressor vibration cryogenic technology year, Wang Yawei, the acid and air separation unit equipped with the air compressor broken shaft accident analysis and repair accident and safety technology value high alarm, is due to the shattering The torque of the guide plate is replaced by the torque of the gas-gut-lock nut, and the instantaneous vibration value of the second-stage impeller with the team flow is increased.) The volute of the air compressor is an integral ring structure, which is caused by the installation. .
Since the vibration value is too high, the stop interlock has a delay second moving low speed rotor, the secondary impeller must be removed from the rotor, so the function is made, so there is no automatic stop at that time.
The collision between the straight two-stage impeller and the shaft adopts a clearance fit, and the gap is connected. The result is that the apex angle of the two ends of the two impellers is hit by one to prevent the shaft and the impeller from rotating relative to each other. crack.
This can be said to be the cause of the broken shaft accident.
The torque of the lock nut is increased to and in the shaft and the impeller due to the rush to restore oxygen production, at the time (plus a cylindrical pin.
Day) It is not only impossible to dismantle this air compressor, but it must be cast aluminum ring on the volute end cover to ensure that the semi-open leaf continues to overload operation.
The vibration and stress concentration causes a gap between the side of the wheel and the ring at the corners of the two blades to be within a range.
The cracks continue to grow and expand.
The ash accumulated at the angle of the impeller is mainly formed on the 9th day of the month, and the repaired air compressor mainframe is formed during the period of Shenyang.
The first test run of the blower factory test bench.
When the spindle speed rises (3) due to the continuous expansion of the blade crack, the two blades are wound to the approximate time (the rated speed is the length of the Shenyang apex angle connected to the body is shorter and shorter, and accordingly, the blower factory is A coupling joint that was machined and tested suddenly twisted the apex angles of the two blades and began to shake under the impact of the airflow.
Month off.
One end of the coupling loses its restraint, and during the inertial motion, the air compressor emits a low and continuous abnormal sound and the vibration value suddenly emerges and flies away at a distance.
The original Japanese coupling was damaged and risen to the anomaly of worship, which is the result.
After that, it was scrapped and the test failed.
The crack accelerates in the jitter.
However, at the time of the damage, the domestic coupling was installed and installed, and the air compressor was not repaired. In order to maintain the oxygen supply, this station carried out the second test.
During the test run, it was found that the secondary vibration value was higher and the air compressor had to operate with disease.
Until the day of the day, the belt fluctuated greatly (the apex angle of the blade after the two-hour test run was broken off during operation, and a clear impact sound was heard at the exit of the secondary impeller.
After disintegration inspection, it was found that the impeller and the aluminum diffuser repeatedly collided, causing the blade outlet side of the secondary impeller to be worn between the damaged rings, especially the secondary aluminum ring has been completely destroyed by the impeller. The low speed rotor gear shaft is at the root of the secondary impeller. Was broken.
Broken, the flaws on the secondary impeller are about this fault. (4) The reason for the alarm and the stop interlock value of this air compressor is that the material of the ring is not properly selected.
The coefficient of thermal expansion of aluminum is about mixing and mixing m, so the vibration value of the secondary shaft before the broken shaft suddenly rises twice as much as that of steel. The aluminum ring set on the steel volute is not as high as 45 weeks in operation. The personnel are highly valued.
At that time, the hot bumps collided with the impeller.
Most people think that this may be caused by the impeller ash falling off, so I didn't learn the lesson of this failure. We decided to stop the first and second levels decisively.
The accident proved that the shape of the ring on the volute end of the shaft vibration value was changed to carbon steel, and the rise of the first and second rotors was a precursor to the broken shaft accident.
After the entire system is re-checked, the watch is removed and the size repair process is repaired. The high-speed dynamic balance is redone.
Due to the high price of the Japanese side, the time required for delivery is long, and in the past 9 years, after repeated and repeated balancing and trial transportation, the transportation procedures are cumbersome and the road is far away.
After careful investigation and research, the secondary vibration value has been high and cannot meet the design requirements.
After the investigation, we decided to take the road of localization and entrusted the Shenyang Blower Factory to analyze it. The reason is that we did not have to repair the structure of this Japanese air compressor, and other work was done by ourselves.
Through, the low-speed rotor secondary impeller and the shaft cooperation scheme (the anus between the Japanese original low-speed rotor in the accident has been unrecognizable, the gap of a cylindrical pin a lock nut) is the reference to the Japanese original so the mapping and copying this road can not get through .
The technical staff of both sides made reference to the big design, and now it seems that this plan is unreasonable.
The data of the related quantity, after repeated research, has developed the following repair scheme. The key problem is that it cannot guarantee the precise positioning of the secondary impeller on the shaft.
The two semi-open impellers are designed by ternary flow theory. During the installation process, it can not guarantee the vertical stainless steel forging material of the impeller and the shaft after disassembly and assembly. It is processed by five-axis CNC milling machine, and its externality does not change. The change in the perpendicularity causes the high-speed dynamic balance path to become unbalanced with the qualified rotor.
In the operation process, since the total length of the centrifugal (2) gear shaft is the function of the pinion modulus of the pinion, the gap between the inner hole of the impeller and the shaft is increased by 51 to increase the number of teeth and the width of the tooth.
To the spell m, plus only one positioning pin, under the action of the torque, (3) the interference fit between the first stage impeller and the shaft, the interference is the side of the impeller biased to the positioning pin, causing the impeller and the shaft to be different. Affect the dynamic balance of the first phase of the accident and the safety technology.
According to the above analysis, we took two measures. The first item is to strictly control the variation of the perpendicularity between the impeller and the shaft during the installation. The second item is to increase the positioning pin between the secondary impeller and the shaft to three symmetrical. .
On the day of the month, the test was resumed at the test bench of the Shenyang Blower Factory and finally succeeded.
The vibration record of the air compressor at the rated speed is shown in the table Wang Yawei, the acid-acid space is equipped with the air compressor broken shaft accident analysis and repairing the air compressor vibration value time secondary three-level repair after the air compressor with load operation summary repair The air compressor was shipped to our factory as a whole.
On the day of installation, the test is completed and the test run with load is started (air supply to air-tolerant equipment).
At present, this air compressor is in good condition and can replace the original Japanese air compressor.
The following is a set of main parameters for the operation of the air compressor at the time of the year, the inlet guide vane opening 52, the exhaust pressure flow, the voltage, the current amplitude, the first stage mixing, the second stage mixing, and the third stage.
However, there is still a certain gap between the original air compressor and the original equipment after the transformation of the old air compressor, mainly in three aspects.
The original air compressor started smoothly and the sound was not loud.
After the repair, the opening of the guide vane of the air compressor is greater than that of the rear sound, and the feeling of crossing the surge zone is particularly obvious. The vibration speed has increased.
The highest vibration value of the air compressor before normal operation is within the range of worship.
After the transformation, the secondary vibration value is operated in the vicinity of the spell m. In addition, the axial vibration speed of the large gear by the oil pump end is changed after the replacement of the coupling mold by Chuanxiong, and the test situation is still not improved.
However, according to the provisions of Section 8 of the Technical Conditions for Large Air Separation Equipment, the vibration speed of the turbine compressor is not more than qualified.
(3) Unit energy consumption has increased.
Before the transformation on the date of the year, the exhaust pressure, the flow rate voltage, the current, the electricity, the hour meter reading, and the unit consumption is not flying/resistant.
After the transformation of the year and month, the situation of exhaust pressure, flow, voltage, current, electricity, electricity, and continents) k total hours of electricity meter reading), resistance.
Compared with before the transformation, the energy consumption of the air compressor has increased. After the localization of this imported air compressor, although the performance and the original Japanese equipment still have a certain gap, but the operation The situation is good and can meet the process requirements.
This localization transformation was a success.
On the date of revision, there were three cases of nitrogen suffocation and death.
At about 30 minutes of the year, Shanghai Coking Co., Ltd. was overhauled with a nitrogen-filled new gas generator, causing people to inhale nitrogen, and people died of severe hypoxia and suffocation. .
On the day of the month, the factory was shut down and repaired. The air compressor buffer tank was shut down. (Before the inspection, the gas was blown off by nitrogen. When a migrant worker wears a filter gas mask and stands outside the tank to clean the hydrolyzate in the tank, the suffocation falls on the tank. Inside, a technician found that he had rescued him and also dumped another worker and found that the canister rescued the technician, but he fell.
After the rescue of the two people in the tank, but the rescue is invalid. .
In the year, the old system of Shandong Lunan Fertilizer Plant was overhauled, and the refrigerator was replaced with nitrogen. Due to leakage inside the valve, nitrogen leaked into the synthetic system refined oil separator. The migrant workers who were carrying out anti-corrosion operations were suffocated, and two of them rescued. Invalid death.
Hangyang Standardization Room Xianghong Collection) I want to be safe, I will start safely from me and guarantee safety.
Cryogenic technology year
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