Understand centrifugal air compressor in one article!
release date：2024-08-22
With the rapid development of technology in my country's air compression industry, air compressors have made great improvements in structural layout and functional form, and centrifugal air compressors have become a new generation of air compression equipment. Due to the lack of understanding of the principles of centrifugal compressors in petrochemical industry production, there is a risk of equipment failure in actual production control. A detailed analysis of the causes and treatment methods of centrifugal compressor failures has a guiding role in the automated scheduling of mechanical equipment.
1. Principle of Centrifugal Compressors
Compressors can be divided into various categories from different perspectives. According to the type of compressor, they are divided into fixed, mobile, and closed types. Centrifugal compressors are one of the most commonly used equipment.
1.1 Principle
Centrifugal air compressors are speed compressors. When the gas load is stable, centrifugal air compressors work stably and reliably. Centrifugal air compressors are driven by impeller" target="_blank">impellers to rotate at high speed, which generates centrifugal force in the gas. Due to the expansion pressure flow of the gas in the impeller, the flow rate and pressure of the gas after passing through the impeller are increased, and compressed air is continuously produced. According to this principle, centrifugal compressors can provide sufficient air pressure in the mechanical transmission system, promote effective linkage between mechanical components, and provide reliable power for the operation of external link devices.
1.2 Features
For the compressors used in the early days, the centrifugal compressors not only have a streamlined and improved component structure, but also the overall structural layout of the compressor is more in line with the operating function of the equipment. At present, centrifugal compressors are assembled with one or more rotating impellers to speed up the flow of gas, which is very helpful for gas pressure control. According to the usage, the gas pressure of the centrifugal air compressor has the characteristics of stability during operation, the degree of wear between the components is relatively light, and it will not cause excessive wear to the mechanical parts. These are all helpful to improve the gas operation speed of the compressor and improve the exhaust efficiency.
2. Operation failure and processing
In recent years, centrifugal air compressors have been used more widely in the chemical industry. This type of equipment not only provides a guarantee for the regulation of its own gas pressure energy, but also provides sufficient gas pressure energy for the compressor connection equipment, thereby driving the high-efficiency operation of the mechanical transmission system. The compressor uses the continuous flow of gas to convert the original mechanical energy of the motor. The working intensity of this process is affected by the working load of the mechanical equipment. In view of the continuous increase in the operating load of mechanical equipment in the chemical industry, the failure rate of centrifugal compressors has also increased significantly.
2.1 Sudden drop in oil pressure
The reason for the sudden drop in compressor oil pressure is relatively complicated and is closely related to the composition of the components in the unit. The handling of this fault should be based on the actual situation. In general, the drop in oil pressure is related to the oil pump, oil pipe and other lubrication system oil pipes. To handle this fault, pressure testing and handling work must be done well. For example, when the oil pump fails, the pressure is also reduced. The oil pump should be checked in time to find out the cause of the failure; when the fault is related to the oil pipe, the fault is caused by the relevant rupture and leakage. The specific measure is to replace the new oil pipe.
2.2 Reduced gas outlet flow
The main reason for the reduction in gas outlet flow is the filter and sealing device. Improper control of these two components will reduce the gas flow and affect the normal function of the compressor equipment. Troubleshooting methods: First, the reduction in air intake caused by gas filter blockage is the main reason for the filter failure. The gas filter can be cleaned to eliminate the fault; second, the reason for the failure of the sealing device is that the sealing gap is too large, causing leakage. The best solution is to replace the seal or adjust it according to regulations.
2.3 The outlet temperature of the cooler is too high
The temperature at the outlet of the gas cooler is greater than 60°C. The occurrence of this fault is related to the cooling water volume of the cooler and its cooling pipe, flow rate, and the coordination between the tube sheet and the tube. For example, the coordination between the tube sheet and the tube is loose or the cooling tube is broken, and the temperature at the outlet of the gas cooler cannot be maintained, which exceeds the allowable range; the operating pressure of the compressor is too high, which increases the wear of the components and produces a significant temperature rise phenomenon. Specific treatment measures include using a tube expander to tighten the loose tube, or blocking both ends of the damaged tube, and cleaning the core of the cooler.
2.4 The bearing temperature is too high
The bearing is the core component of the centrifugal compressor operation failure, which determines the operating efficiency of the entire equipment. Excessive bearing temperature is a common fault in the operation of the compressor. The main manifestations of temperature failure are: the throttle ring aperture of the oil inlet of the bearing is too small, the oil inlet is insufficient; the oil pressure of the lubrication system drops or the oil filter is blocked, the oil inlet is reduced; the cooling water of the oil cooler is insufficient, and the oil inlet temperature is too high. According to these fault phenomena, the actual processing process requires repairing the lubrication system oil pump, oil pipe or cleaning the oil filter; adjusting the water inlet of the oil cooler cooling water; the throttle ring aperture of the oil inlet of the bearing is too small, the oil inlet is insufficient, and the throttle ring aperture is appropriately increased; repair the oil cooler, eliminate the water leakage fault or replace new oil.
2.5 Excessive bearing vibration
The vibration load increases the bearing load range and causes the failure and loss of the centrifugal air compressor structure, which is very harmful to the damage of parts. The fault manifestations of excessive bearing vibration load: the dynamic balance accuracy of the rotor or speed increaser gears is destroyed; the interference between the bearing cover and the bearing back is too small; the gear meshing is poor, the gear is severely worn or damaged. For this type of fault handling, the main method is to recalibrate the dynamic balance; scrape the horizontal center surface of the bearing cover or grind the adjustment gasket to ensure that the interference is 0.02-0.06mm; check the gear wear, recalibrate the non-parallelism, center distance and meshing area between the large and small gears to meet the requirements.
2.6 Poor cooling effect of the cooler
The cooler is mainly used to adjust the stability of the internal temperature of the compressor, maintain a balanced temperature to create a superior compressor operating environment, and the cooling failure affects the function of the entire equipment. The main fault manifestations: reduced cooling capacity of the gas cooler; dirt on the surface of the cooling pipe; rupture of the cooling pipe or loose fit between the pipe and the tube sheet. To handle the cooler failure, it is necessary to check the components from many aspects, and focus on checking the cooling water volume. The water flow rate in the cooler pipe should be less than 2m/s; clean the cooler core; block the two ends of the damaged pipe or use a tube expander to expand the loose pipe. If necessary, the cooler can be re-installed to improve the cooling effect of the actual operation of the compressor and reduce the incidence of cooling failures.
3. Daily maintenance of centrifugal compressors
Based on the background of industrial science and technology reform, many mechanical equipment have been promoted and applied in industry production. Air compressors are responsible for converting mechanical energy into gas pressure energy, which facilitates the daily operation and regulation of mechanical automatic control systems. On the one hand, regularly check the functional status of the compressor mechanical system, detect fault hazards through equipment debugging methods, and do a good job in handling operating faults in advance; on the other hand, disassemble and inspect the main components such as bearings and coolers to determine whether there are problems such as wear and lubrication of mechanical parts, and replenish lubricating oil in time to improve the system operation efficiency; for some aging compressor equipment, new equipment or components can be replaced when necessary, which is also an effective way to prevent faults.
4. Conclusion
Centrifugal air compressors optimize and upgrade the structure of traditional compressors, improve the conversion efficiency of compressors to electric mechanical energy, promote mechanical energy to generate more air pressure energy, and drive the automation control of chemical machinery and equipment systems. In view of the functional characteristics of centrifugal air compressors, enterprises must do a good job in fault handling when selecting such equipment, promptly solve the fault risks existing during the operation of the compressor, and reduce the functional damage caused by faults to mechanical equipment. In addition to timely handling of various faults, it is also necessary to regularly inspect and maintain compressor components to effectively prevent the failure rate of compressor operation.
Source: Internet
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