The Primary Cause of Unstable Operation of Screw Air Compressors
Thanks to remarkable high efficiency and energy-saving performance, twin-screw air compressors have been widely adopted in industries and become the preferred model for air compressor upgrading. During practical operation, carbon deposits and scaling are the biggest issues hindering the long-term stable operation of such compressors.
Causes of Carbon Deposits in the Oil Circuit of Air Compressors
The formation mechanism of carbon deposits inside air compressors is complicated. Large dust particles can enter the unit if the air filter fails to intercept contaminants. In terms of lubricating oil: the lubricant inside the air compressor exists in an atomized state and contacts air under high temperature, high pressure and high oxygen partial pressure together with metallic catalytic surfaces, leading to rapid oxidation and deterioration of lubricating oil.
On the other hand, continuous oil evaporation leaves heavy oil fractions inside the exhaust pipeline, which undergo thermal decomposition and dehydrogenation polymerization. The reaction products mix with mechanical impurities in intake air and metal wear debris generated inside the compressor. These mixtures settle on equipment surfaces and are further heated, eventually forming carbon deposits.
Causes of Scaling in the Water Cooling System of Air Compressors
Cooling water circulates continuously. Water evaporation concentrates various inorganic ions and organic substances, and dust and debris also enter the water loop. Coupled with rising water temperature, the solubility of carbonate declines. Meanwhile, dissolved carbon dioxide escapes and breaks the carbonic acid equilibrium, facilitating carbonate precipitation. Dense carbonate scale accumulates on the surfaces of heat exchangers and pipeline walls.
Hazards of Scaling and Carbon Deposits in Air Compressors
Main Hazards Caused by Scaling on Heat Exchange Equipment
Poor heat transfer leads to sustained excessive thermal load on heat exchange surfaces, which easily degrades the mechanical properties of surface metal materials.
It triggers under-deposit corrosion of metal components and further impairs metal mechanical performance.
It may cause operational safety accidents including bulging, cracking, leakage and pipe bursting of heat exchange pipelines.
Main Hazards Caused by Carbon Deposits in Lubricating Oil Systems
Poor lubrication of moving components and shortened service life of spare parts.
Easy blockage of filter screens inside the oil-gas separation device.
Carbon deposits hinder heat dissipation, forcing the air compressor to run at elevated temperatures for long periods.
Risk of safety accidents (air compressor explosion under severe conditions).
Treatment Methods for Scaling and Carbon Deposits in Air Compressors
Traditional Cleaning Methods for Air Compressor Heat Exchangers
Physical cleaning methods mainly include manual scraping, grinding and high-pressure water flushing.
For chemical cleaning: when scaling impairs heat transfer, acid cleaning combined with high-pressure flushing is commonly adopted to maintain heat exchangers. Nevertheless, the descaling process is complex. Operators need rich experience to control the dosage, concentration of acid/alkaline agents and treatment duration. Improper operation may cause excessive corrosion and damage heat exchange equipment and pipelines during descaling.
For air compressor oil circuit cleaning: one method is to add cleaning agent into the unit, operate the compressor for 500 hours, drain the waste oil, and replace the three filter elements for routine maintenance.
The alternative method requires dismantling the cooler, main unit and oil pipelines. A dedicated carbon deposit cleaner is mixed with water at a specified ratio; cleaning is realized by soaking and circulating the mixture with a small water pump.
Other cleaning approaches for carbon deposits include complete disassembly cleaning, partial disassembly cleaning and closed-loop cleaning.
Preventive Measures Against Carbon Deposits in Air Compressors
Prevent carbon deposits starting from the air filter
Adopt high-quality dedicated lubricating oil
The air filter element serves as a vital protective barrier for air compressors to remove dust and impurities from intake air. Cleaner intake air effectively extends the service life of oil filter elements, oil-gas separation cores and lubricating oil.
Rotor lubricating oil plays a decisive role in lubricating compressor rotors, bearings and gears. High-quality lubricating oil ensures cooling and lubrication of the air compressor. Meanwhile, it exerts critical influences on compressor operating efficiency, system corrosion resistance and rotor service life. Most importantly, it can inhibit the generation of carbon deposits.
Causes of Carbon Deposits in the Oil Circuit of Air Compressors
The formation mechanism of carbon deposits inside air compressors is complicated. Large dust particles can enter the unit if the air filter fails to intercept contaminants. In terms of lubricating oil: the lubricant inside the air compressor exists in an atomized state and contacts air under high temperature, high pressure and high oxygen partial pressure together with metallic catalytic surfaces, leading to rapid oxidation and deterioration of lubricating oil.
On the other hand, continuous oil evaporation leaves heavy oil fractions inside the exhaust pipeline, which undergo thermal decomposition and dehydrogenation polymerization. The reaction products mix with mechanical impurities in intake air and metal wear debris generated inside the compressor. These mixtures settle on equipment surfaces and are further heated, eventually forming carbon deposits.
Causes of Scaling in the Water Cooling System of Air Compressors
Cooling water circulates continuously. Water evaporation concentrates various inorganic ions and organic substances, and dust and debris also enter the water loop. Coupled with rising water temperature, the solubility of carbonate declines. Meanwhile, dissolved carbon dioxide escapes and breaks the carbonic acid equilibrium, facilitating carbonate precipitation. Dense carbonate scale accumulates on the surfaces of heat exchangers and pipeline walls.
Hazards of Scaling and Carbon Deposits in Air Compressors
Main Hazards Caused by Scaling on Heat Exchange Equipment
Poor heat transfer leads to sustained excessive thermal load on heat exchange surfaces, which easily degrades the mechanical properties of surface metal materials.
It triggers under-deposit corrosion of metal components and further impairs metal mechanical performance.
It may cause operational safety accidents including bulging, cracking, leakage and pipe bursting of heat exchange pipelines.
Main Hazards Caused by Carbon Deposits in Lubricating Oil Systems
Poor lubrication of moving components and shortened service life of spare parts.
Easy blockage of filter screens inside the oil-gas separation device.
Carbon deposits hinder heat dissipation, forcing the air compressor to run at elevated temperatures for long periods.
Risk of safety accidents (air compressor explosion under severe conditions).
Treatment Methods for Scaling and Carbon Deposits in Air Compressors
Traditional Cleaning Methods for Air Compressor Heat Exchangers
Physical cleaning methods mainly include manual scraping, grinding and high-pressure water flushing.
For chemical cleaning: when scaling impairs heat transfer, acid cleaning combined with high-pressure flushing is commonly adopted to maintain heat exchangers. Nevertheless, the descaling process is complex. Operators need rich experience to control the dosage, concentration of acid/alkaline agents and treatment duration. Improper operation may cause excessive corrosion and damage heat exchange equipment and pipelines during descaling.
For air compressor oil circuit cleaning: one method is to add cleaning agent into the unit, operate the compressor for 500 hours, drain the waste oil, and replace the three filter elements for routine maintenance.
The alternative method requires dismantling the cooler, main unit and oil pipelines. A dedicated carbon deposit cleaner is mixed with water at a specified ratio; cleaning is realized by soaking and circulating the mixture with a small water pump.
Other cleaning approaches for carbon deposits include complete disassembly cleaning, partial disassembly cleaning and closed-loop cleaning.
Preventive Measures Against Carbon Deposits in Air Compressors
Prevent carbon deposits starting from the air filter
Adopt high-quality dedicated lubricating oil
The air filter element serves as a vital protective barrier for air compressors to remove dust and impurities from intake air. Cleaner intake air effectively extends the service life of oil filter elements, oil-gas separation cores and lubricating oil.
Rotor lubricating oil plays a decisive role in lubricating compressor rotors, bearings and gears. High-quality lubricating oil ensures cooling and lubrication of the air compressor. Meanwhile, it exerts critical influences on compressor operating efficiency, system corrosion resistance and rotor service life. Most importantly, it can inhibit the generation of carbon deposits.
