The oil-free air generator, through the synergistic effect of oil-free compression, multi-stage purification, membrane separation or adsorption technology, provides a high-purity and oil-free stable gas source for laboratory and industrial scenarios. Its technical route can be divided into the following three core stages:
1、 Oil free compression: eliminating oil pollution from the source
The oil-free air generator adopts an oil-free lubrication compressor (such as diaphragm or vortex), which replaces traditional lubricating oil with mechanical seals or polymer materials to avoid the mixing of oil vapor into the gas path during compression. The compressed air temperature significantly increases and needs to be rapidly cooled through air or water cooling systems to prevent gas volume expansion caused by high temperatures from affecting subsequent processing efficiency. At the same time, the water vapor content is reduced to alleviate the drying burden.
2、 Multi stage purification: removing particles, moisture, and trace impurities
Primary filtration: Remove particles and liquid water droplets with a diameter greater than 5 μ m through centrifugal or filter type separators to protect subsequent precision filters.
Precision filtration: Activated carbon filter cartridge is used to adsorb organic compounds, odors, and some water vapor. Molecular sieve or silica gel desiccant is further dehydrated to reduce the dew point to below -40 ℃.
Terminal purification: A 0.01 μ m micro oil mist filter intercepts residual oil molecules and submicron particles, ensuring that the output air oil content is less than 0.003ppm, meeting the requirements of precision instruments such as gas chromatographs.
3、 Core Separation Technology: Comparison of Membrane Separation and Pressure Swing Adsorption Routes
Membrane separation technology:
By utilizing the selective permeability of hollow fiber membranes, under pressure differential driving, small molecule gases such as oxygen and carbon dioxide preferentially pass through the membrane wall, while large molecule gases such as nitrogen are intercepted, achieving rapid separation of nitrogen with a purity of 95% -99%. This technology has no moving parts and is easy to maintain, but its gas production efficiency is limited by the membrane area, making it suitable for low flow scenarios.
Pressure swing adsorption (PSA) technology:
By utilizing the characteristics of carbon molecular sieves adsorbing oxygen under pressure and desorbing under pressure, the adsorption tower can be cyclically switched to achieve continuous gas supply. PSA can produce 99.99% high-purity nitrogen with flexible and adjustable gas production, but requires regular replacement of molecular sieves and a complex pneumatic valve control system, suitable for high flow requirements.