The reason for the high vibration of the high-pressure cylinder is analyzed and corresponding improvement measures are proposed. The performance parameter high-pressure cylinder is a cylindrical structure consisting of three impellers of three or four sections. The impeller is arranged in a back-to-back mode. The axial force is balanced by the thrust bearing. The radial bearing is made of tilting pad bearings and consists of five tiles. Oil seal oil drain hole, the problem of the inlet passage to the opening. Since the unit has been running since the test run, the vibration value of the high pressure side radial watt of the compressor high pressure cylinder has been high, reaching 75 production exceeding the alarm value, sometimes even higher, forcing the process. The interlock is removed to maintain operation. This state makes the compressor unit extremely unstable, and many accidents occur, which becomes a hidden danger of safe and stable operation of the production.
After many years of analysis of the operating state of the high-pressure cylinder of the unit and the on-line monitoring spectrum analysis of the radial vibration value of the high-pressure cylinder, the inspection records have been reviewed several times. It is believed that the main reason for the unstable and high vibration value of the high-pressure cylinder radial wattage is Radial tile. Therefore, in the use of parking opportunities in the years, we have comprehensively tested and repaired the radial pads of the high-pressure cylinders. After the overhaul, the compressor unit is put into operation, and the vibration value of the radial wattage in front of the high-pressure cylinder is mixed with the following operation, which better solves the problem of high vibration value of the high-pressure cylinder, and the unit has been transferred to a good operating state since then. The operating cycle is extended. Analysis and solution to the vibration of the high-pressure cylinder radial tile.
From the spectrum analysis, it is further confirmed that if the alignment is not good, the amplitude of the second harmonic is large, and the result is that the double frequency is small.
The rotor imbalance is also the main cause of vibration. Its main feature is that the radial amplitude at the bearings at both ends of the compressor will increase simultaneously with the number of revolutions and load of the unit, and our carbon dioxide high pressure cylinder is always the front diameter. To the Waigao, the vibration value of the other side is within the design range. In addition, after checking the records, the rotor was dynamically balanced in the Lanhua Machinery Plant in the following year.
Oil film whirl and oil film oscillation cause vibration oil film whirl and oil film oscillation are self-excited vibration caused by mechanical properties of oil film in sliding bearing. The sharp increase of spindle amplitude due to oil film rupture often leads to catastrophic accident of unit damage. Phenomena occur mostly in elliptical tile structures. The tile of the tilting pad bearing is in line contact with the tile shell, and can swing around the fulcrum, forming a convergence space between the tile surface and the journal.
Since the tile can swing with the load, it can automatically adjust the gap between it and the journal to change the bearing capacity of the oil film. Therefore, the tilting tile bearing generally does not have oil film oscillation, and the carbon dioxide compressor high-pressure cylinder radial bearing adopts a five-watt block bearing, so that this phenomenon can be eliminated. The rotor of the rotor hot-sleeve fitting is insufficient. The impeller on the rotor of the high-speed rotator such as the gas turbine compressor is usually mounted on the shaft by means of hot-pressing. The cooperation of the shaft and the disk parts such as the impeller is an interference fit.
If the interference is not enough, the disk parts such as the impeller will have a gap with the shaft under the centrifugal force generated by the high-speed rotation of the rotor, and there will be relative sliding between the mating surfaces. The larger the sliding amount, the more the vortex speed of the rotor will be. Large, causing rotor motion instability. After reviewing the original record of the running rotor, it is known that the impeller between the impeller and the main shaft is in between, which is in accordance with the design value, thus eliminating the possibility of such a reason. There are problems with the bearing. There are mainly gaps in the bearing. The gap is not suitable. The contact is not good enough. The lubricating oil is not suitable for the lubricating oil. In the process of overhauling the high-pressure cylinder of the compressor unit in recent years, each maintenance is strictly in accordance with the technical requirements of the maintenance regulations, and the radial bush of the high-pressure cylinder is installed. It is often that when the vehicle is just driving, the radial vibration value of the front of the high-pressure cylinder is low, generally in the foot, but after running for a period of time, after several times of loading and subtraction, the radial vibration value of the high-pressure cylinder will rise to the material. It will even reach the foot of the material.
In the previous inspections, when the front radial bushing clearance of the high-pressure cylinder was reviewed, it was found that the clearance value after each operation was larger than the clearance during installation, and the clearance was obtained during the inspection. There is no obvious wear on the tile. For this large amount of variation, we initially think that the reason should be on the radial tile. When the radial vibration of the high-pressure cylinder rises, the advanced spectrum monitor is used to monitor the front radial vibration a4 of the high-pressure cylinder. It is found that the vibration spectrum is mainly based on the power frequency, and the change is obvious and accompanied. The load increases and decreases and fluctuates up and down. Through the analysis of the spectrum, it is further revealed that the reason for the high vibration of the front radial tile is mainly caused by poor contact of the radial pads or changes in the gap.
We used the parking opportunity to overhaul the high pressure cylinder of the CO2 compressor unit. In order to further confirm whether the previous analysis and judgment is correct, the center will be carefully reviewed. The data of the review and the data at the time of installation are basically the same. The back-grid force of the thrust plate is not misaligned, and these data are repaired. The measured data is identical, only the front radial watts, that is, the wattage is the raw data, and the display of these data confirms that the previous theoretical inference is correct. Therefore, this inspection is based on the previous analysis focus on the tile of the front radial tile of the high pressure cylinder.
From the inspection situation, the surface of the radial tile in front of the high-pressure cylinder is not obviously worn, and the journal has no obvious wear, but the increase of the amount of wattage does exist. After the tile surface of the tile and the adjustment pad were cleaned and washed many times, it was found that the value of the tile thickness changed greatly each time, and then the red tile powder was used to contact the tile with the matching pad, and the display was performed. It is very clear that only the two sides of the adjustment pad are in line contact with the tile, the middle portion has no contact point, and the adjustment pad on the tile is in rough contact with the tile.
In order to make the tile not scrapped, and the stainless steel skin added after the adjustment pad, the total thickness of the tile is restored to the end of the adjustment, the unit is reloaded, and the gap between the tile and the high pressure cylinder is still used. Tile, because the surface of the old tile is more reliable after it has been worn-in, and the contact with the shaft.
Considering that the tile pillow was sunk in the previous overhaul, it has been pocked on it. In order to make the tile frame and the tile pillow have no imaginary contact, the front radial bushing force of the high pressure cylinder is adjusted to the rest of the components. Reload according to the technical requirements of the maintenance procedures. After the compressor unit is operated, the load is the standard value of the Ningxia Petrochemical Year's lining, and the high pressure cylinder is thrown. After the overhaul, after four times of loading and unloading and opening and stopping, the vibration value remained basically unchanged, indicating that the overhaul solved the problem of high radial vibration value of the high pressure cylinder. Re-use of the spectrum to test the front radial wattage a4 of the high-pressure cylinder, and find that the vibration spectrum of the front radial wattage of the high-pressure cylinder is mainly based on the power frequency, but its amplitude is significantly reduced. The overhaul solves the problem of high radial vibration value and easy fluctuation of the high pressure cylinder, indicating that the problem of radial tile is indeed present. In the future inspection and overhaul of the compressor unit, targeted maintenance should be carried out to ensure the safe and stable operation of the compressor unit.
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