The standard operating steps for the hot reflux extraction concentrator can be divided into the following four stages, which must be strictly followed to ensure safety and efficiency:
1、 Preparation before startup
1. Equipment inspection:
Confirm the sealing of the slag discharge door, the status of each valve, and the absence of leaks in the pipeline, and complete the equipment cleaning.
Check that the steam pressure, cooling water supply, vacuum system, and power supply are operating normally.
2. Feeding and soaking:
Weigh the medicinal herbs according to the process requirements and put them into the extraction tank. Add a solvent (such as water or ethanol) that is 5-10 times the weight of the herbs.
Close the feeding port, open the top vent valve of the tank to balance the pressure, and soak the medicinal herbs for the set time (usually 30-60 minutes).
2、 Extraction and Hot Reflux Cycle
1. Start extraction:
Start the cooling water system, inject steam into the extraction tank jacket or through steam valve, slowly heat it to boiling, and then adjust the amount of steam to small after base note to maintain the state of slight boiling.
Key operation: Keep the vent valve open during boiling to prevent pressure accumulation from causing explosive boiling.
2. Hot reflux cycle:
After boiling for 20-30 minutes, start the vacuum system to draw about 1/3 of the extraction liquid into the concentrator.
Close the steam valve of the extraction tank and turn on the concentrator for heating. The secondary steam generated by concentration is liquefied by the condenser and refluxed to the extraction tank as a new solvent.
Control the reflux temperature between 40-80 ℃ (water extraction should be ≤ 90 ℃, alcohol extraction should be ≤ 80 ℃) to ensure effective ingredient dissolution and reduce impurities.
3. Dynamic loop control:
Maintain the extraction concentration cycle for 2-4 hours until the extract is close to colorless, indicating that the active ingredients have been largely removed.
3、 Concentrate and terminate reflux
1. Independent concentration stage:
Close the reflux valve, open the vacuum valve of the concentrator (maintain a vacuum degree of ≥ -0.06MPa), and switch the secondary steam to the cooler.
Adjust the liquid inlet of the concentrator, maintain the liquid level at the centerline of the sight glass, and continue heating and concentrating until the liquid extract reaches a specific weight of 1.1-1.34.
2. Endpoint judgment:
Sample and test the specific gravity of the concentrated solution. Once it meets the standard, immediately close the heating valve and vacuum system, and release the concentrated paste while it is still hot to prevent wall sticking.
4、 Closing operation
1. Solvent recovery:
If using organic solvents such as ethanol, add water and steam to recover residual solvents.
2. Cleaning and maintenance:
Drain the remaining liquid medicine from the extraction tank to the storage tank, and open the slag discharge door to remove the residue.
Activate the online cleaning system (CIP) to sterilize the equipment and clean residues.
5、 Key points of safety and efficiency
1. Explosion proof boiling control: During the boiling stage, the vent valve must be opened, and the operation of organic solvents requires an explosion-proof environment.
2. Accurate temperature control: Low temperature concentration (50-80 ℃) preserves thermosensitive components and avoids the accumulation of medicinal materials to form a "cold pile".
3. Cycle interruption handling: If the hot reflux process is interrupted, the solvent equilibrium needs to be re established before continuing the operation.
Throughout the operation, pressure, temperature, and vacuum degree need to be monitored to ensure compliance with the process parameter range.