Supercritical CO2 equipment for the treatment of agarwood process

The following is a summary of the process and related technology for treating agarwood based on supercritical carbon dioxide (SC-CO₂) equipment:

Pre-treatment stage

• Crushing and soaking: After crushing the agarwood, soak it in 95% ethanol. The soaking time varies greatly in different processes, such as soaking for 12 hours (mass ratio 1:5) in the patented technology, while the optimization experiment shows that the best soaking time is 83 hours.
• Evaporation and concentration: The ethanol soaking solution is passed through the rotary evaporator to remove the solvent and get the agarwood paste, which is used as the raw material for the subsequent supercritical extraction.

Supercritical extraction stage

Core parameters:

• Extraction pressure: 21-28 MPa;
• Temperature: 45-47°C;
• CO₂ flow rate: 2-6 L/h or adjusted according to the equipment;
• Separation parameters: pressure 8 MPa, temperature 40 ℃.

Extraction time: 2-3 hours is recommended.

Separation and oil collection
Through the first-stage separation system, the essential oil of agarwood is collected, and the extraction rate can reach 1.89% (after optimization), which is significantly higher than the traditional water vapor distillation method.

Specialized extraction kettle design

• Adopting multi-stage basket structure, with staggered air inlet at the bottom of each stage of the basket, so that CO₂ forms a circuitous path, increasing the contact area with the agarwood powder, reducing the phenomenon of "columnar flow", and improving the extraction efficiency.
• Metal mesh filtration (100-250 mesh) and rounded air inlet design further optimize the fluid distribution.

Process optimization results

• Response surface method experiments show that the optimal combination of conditions (e.g., pressure 28 MPa, material-liquid ratio 1:1.2) can increase the extraction rate to 1.89%, which is about twice as much as the traditional method.

High efficiency and safety

• Supercritical CO₂ extraction avoids the risk of organic solvent residue, and the low operating temperature (40-47℃) protects the heat-sensitive components such as chromone and sedum furan.
• Short extraction time (2-3 hours) and controllable equipment cost.

Component retention intact

• Compared with vapor distillation, supercritical extraction can simultaneously extract volatile components (e.g., balsamic acid) and non-volatile components (e.g., resins, plant waxes), retaining a fuller spectrum of active substances.
• The crude oil has a high percentage of bioactivity, and the refined oil has no solvent residue, making it suitable for the food and cosmetic industries.

Applicable Scenarios

• It is suitable for the industrialized production of high value-added essential oil of agarwood, especially suitable for the pharmaceutical and high-end spice fields which require high purity of essential oil.

Cost and equipment requirements

• The initial investment of supercritical equipment is high, but the long-term running cost is low (CO₂ can be recycled).
• Need to adjust the parameters in combination with the characteristics of raw materials, such as low-grade incense wood needs to be more fine crushing pretreatment.