How much will the efficiency of an air compressor that has been used for 10 years drop?

Analysis of the decline in the efficiency of the air compressor after 10 years of use and its influencing factors.

In industrial production, as the core power equipment, the operating efficiency of air compressor directly affects the energy consumption cost and production stability of enterprises. It has been verified by industry practice that the efficiency of air compressors used for 10 years is usually reduced by 15%-30%, but the specific value needs to be comprehensively evaluated in combination with equipment type, maintenance level and operating environment.

The core influencing factors of 1. efficiency decline

1. equipment aging mechanism
   the core components of the air compressor, such as the main rotor, bearings, seals, etc., will produce physical wear during long-term high-speed operation. Take the screw air compressor as an example, the internal leakage will increase by 8-12% for every 0.01mm increase in the gap between the yin and yang rotors, which directly leads to the reduction of compression efficiency. The use of 10 years of equipment, the rotor gap expansion rate can reach 30-50%, significantly affecting the gas production.

2. System matching deterioration

• pipeline fouling: the accumulation of oil and rust on the inner wall of the compressed air pipeline reduces the effective flow area of the pipe diameter by 15-20% and increases the pressure drop of the system.
• Valve internal leakage: the old equipment of the intake valve, the minimum pressure valve sealing surface wear, leakage rate of up to 5-8% of the rated flow.
• Cooling system recession: water-cooled unit heat exchanger fouling thickness of 1mm, the cooling efficiency decreased by 25%, resulting in increased exhaust temperature, thereby reducing the compression efficiency.

3. control accuracy degradation
   old models mostly use mechanical pressure regulating devices, and the pressure fluctuation range can reach ± 0.1MPa, which consumes 12-18% more electric energy than the new digital control system (± 0.02MPa).

Quantitative performance of 2. efficiency decline

1. gas production attenuation
   take 37kW screw air compressor as an example, the rated gas production of the new machine is 6.0m & sup3;/min, after 10 years of use:

• routine maintenance model: gas production drops to 4.8-5.1m & sup3;/min (attenuation 15-20%)
• for models that neglect maintenance: gas production may be as low as 4.2m & sup3;/min (attenuation 30%)

2. specific power rise
   specific power (kW/m & sup3;/min) is a key measure of energy efficiency. The specific power of the new machine is about 6.2kW/m & sup3;/min, after 10 years of use:

• good maintenance: specific power increased to 7.1-7.5kW/m & sup3;/min (increased by 14-21%)
• maintenance loss: specific power may reach 8.0kW/m & sup3;/min or more (29% increase)

the Impact of 3. Operation and Maintenance Management on Efficiency

1. maintain input-output ratio

• regular maintenance (every 2000 hours): it can delay the efficiency attenuation by more than 50%, and the annual maintenance cost is about 3-5% of the equipment value.
• Preventive overhaul (every 4 years): replacement of core components such as bearings and seals can restore equipment efficiency to 85-90% of the new machine.

2. Typical Maintenance Missing Consequences

• deterioration of lubricating oil: failure to replace on time will lead to a 30% increase in oil viscosity and an 18% increase in friction power consumption of the main engine.
• Filter element blockage: when the pressure difference of the air filter exceeds 0.02MPa, the gas production will decrease by 8-12%.
• Cooling system failure: poor heat dissipation leads to a decrease of 3-5% in energy efficiency for every 10 ℃ increase in exhaust temperature.

4. efficiency improvement suggestions

1. technical transformation scheme

• frequency conversion transformation: no-load energy consumption can be reduced by 30-50%, and comprehensive energy efficiency can be improved by 15-20%.
• Waste heat recovery: using compression heat to prepare hot water, the comprehensive energy efficiency of the system can be increased by 8-12%.
• Intelligent group control: through pressure-flow linkage control, reduce venting loss and achieve energy saving of 10-15%.

2. Device Update Decision
   it is recommended to consider a device update when:

• overhaul costs exceed 40% of the purchase price of the new machine
• energy efficiency is more than 25% lower than the new machine
• critical components still unable to meet production needs after repair

understanding the efficiency attenuation mechanism of air compressor is helpful for enterprises to formulate scientific equipment management strategies. It is recommended to establish a full life cycle management system, through regular testing, preventive maintenance and technical transformation, to delay the rate of efficiency decay, while ensuring the continuity of production, while maximizing energy efficiency. For 10-year-old equipment, professional energy efficiency evaluation should be carried out, and overhaul, modification or renewal plan should be selected according to the evaluation results.