At normal temperature (or low temperature) and a certain pressure, the material is subjected to countercurrent extraction with a liquefied subcritical solvent to obtain the extraction liquid (liquid phase) and the raffinate (solid phase). The solvent in the extraction liquid (liquid phase) is evaporated , vaporize the solvent and separate the extracted target components to obtain one of the products; the extracted material, the raffinate, evaporates the solvent adsorbed in it to obtain another product.

The vaporized solvent is liquefied and recycled. The entire extraction process can be carried out at room temperature or lower, so the biggest advantage is that it will cause less damage to the heat-sensitive components in the material.

In the extraction stage, the raw materials and subcritical fluid are mixed in a closed pressure vessel. By controlling the temperature and pressure, the fat-soluble components in the raw materials are fully dissolved into the subcritical fluid. In the separation stage, the extraction agent is separated from the dissolved components by reducing the pressure or increasing the temperature, so that the fat-soluble components are purified and separated. Then in the refining stage, we further purify and dry the separated fat-soluble components to obtain high-quality oil products.

Subcritical low-temperature extraction processes offer many advantages. Since the extraction is carried out at low temperatures, heat-sensitive ingredients can be protected from damage and loss caused by high temperatures. Secondly, this process uses green and environmentally friendly extraction agents, such as propane, butane, etc., which are not only harmless to the human body, but also environmentally friendly. In addition, the subcritical low-temperature extraction process also has the characteristics of high-quality, energy-saving, and environmental protection, which makes it have broad application prospects in the field of future oil production.