Oil content of oil injection air compressor

Official instructions on the oil content of oil-injected air compressors

oil-injected air compressor is a commonly used compressed air power source in the industrial field, and its exhaust oil content is directly related to the safety of gas-using equipment and product quality. After technical analysis and industry practice verification, the oil content standard, control technology and industry application requirements are described as follows:

1. oil content core indicators

1. general industry standards
   • the oil content in the exhaust of the oil-injected screw air compressor should be ≤ 3 mg/m & sup3;(3ppm), exceeding this value is called "high fuel consumption", which is a common failure phenomenon.
   • Medical, food and other special industries have stricter requirements: breathing equipment gas needs ≤ 0.5 mg/m & sup3;, process gas for direct contact with products needs ≤ 0.1 mg/m & sup3;.
2. detection and determination
   • use infrared spectrophotometry or chemical indicator tube method for detection, and the detection period shall be less than or equal to 30 minutes.
   • A small amount of oil at the bottom of the gas storage tank is normal. Hot oil return pipe does not mean that the oil return is normal. It needs to be judged by the amount of oil stored at the bottom of the oil.

2. oil content control technology

1. oil and gas separation system
   • mechanical collision method: oil droplets with diameter> 1μm are separated by collision of the inner wall of the oil and gas separation barrel, and the separation efficiency is ≥ 99%.
   • Affinity coalescence method: using ultra-fine glass fiber filter element, the <1μm oil droplets are coalesced into large oil droplets, and the separation accuracy is 0.01 μm.
   • Key parameter control: the flow rate of compressed air entering the oil and gas separation barrel is 15-25 m/s, and the flow rate through the filter element is less than or equal to 0.7 m/s.
2. Exhaust pressure optimization
   • for every 3bar decrease in exhaust pressure, the oil content may increase by 5-8 times. Low pressure applications (such as fermentation gas supply) require a specially designed oil and gas separation system.
   • Typical case: oil content 0.63 mg/m & sup3 at 8bar exhaust pressure;, up to 8.44 mg/m & sup3 at 2.5bar;, which needs to be solved by increasing the volume of the oil and gas separation barrel.
3. Post-processing strengthening scheme
   • precision filter: the filtration accuracy is 0.01 μm, which can reduce the oil content to <0.01 mg/m & sup3;.
   • Activated carbon adsorption: used for oil vapor removal, adsorption efficiency increased by 70% under low temperature conditions.

Impact of 3. oil content exceeding standard

1. equipment operation risk
   • pneumatic valve: oil stains cause the driving parts to be stuck, and the response time of the valve switch is extended by 30-50%.
   • Sensor: positive pressure ventilation device sensor due to oil pollution, the failure rate increased by 4 times.
   • Sealing system: dry gas seal spring is stuck, dynamic and static ring wear is aggravated, and the service life is shortened by 60%.
2. Product Quality Risk
   • fermentation production: oil content> 0.5 mg/m & sup3; When the cell growth and metabolism are inhibited, the product synthesis efficiency is reduced by 20-30%.
   • Electronic manufacturing: Oil pollution leads to a 15% drop in chip packaging yield and an increase in maintenance costs.

4. industry application specification

1. fermentation Production Scenarios
   • three-stage filtration system shall be configured: pre-filter (5μm)+ precision filter (1μm)+ sterilization filter (0.01 μm).
   • Regular testing: Compressed air microbiological testing shall be carried out before each batch of production, and the total number of bacterial colonies shall be less than or equal to 10CFU/m & sup3;.
2. Medical gas scene
   • adopt two-stage filtration structure: primary filter (1μm)+ activated carbon filter, residual oil ≤ 0.003 mg/m & sup3;.
   • Verification requirements: Compressed air system verification shall be carried out every year, including particle size, moisture and oil vapor detection.

5. Maintenance Management Requirements

1. daily inspection
   • check the amount of oil stored at the bottom of the oil, and the oil level of the return pipe mirror should be less than 1/3 height.
   • When the exhaust temperature is monitored, the viscosity of the oil decreases and the separation efficiency decreases when the temperature exceeds 98 ℃.
2. Regular maintenance
   • replace the oil and gas separation filter element every 2000 hours, and replace it in advance when the resistance exceeds 0.05MPa.
   • Check the safety valve every year, and set the pressure to 1.05-1.1 times the design pressure.

The oil content control of oil injection air compressor is a system engineering, which needs to be controlled from the whole process of equipment selection, system configuration and operation and maintenance. Enterprises should establish an oil content monitoring system, and formulate personalized control plans based on process requirements. For high-risk industries such as medical and food, it is recommended to configure online oil content detectors to achieve real-time monitoring and early warning of oil content to ensure gas safety and product quality.