Static Extraction Tank

Static extraction vessels, also known as static multi-functional extraction vessels, are non-stirring static extraction equipment. They are suitable for processes such as atmospheric pressure, reduced pressure, pressure, water decoction, percolation, forced circulation, thermal reflux, volatile oil extraction and organic solvent recovery in the Chinese herbal medicine, plant, animal, food, biological medicine and chemical industries.

Static extraction vessels can achieve vacuum reduced pressure extraction to lower the boiling point. The main forms of static extraction vessels include four types: positive cone – type extraction vessels, inclined cone – type extraction vessels, straight cylinder – type extraction vessels and mushroom – type extraction vessels. The most commonly used one is the positive cone – type extraction vessel.

Positive cone – type extraction vessels, inclined cone – type extraction vessels, straight cylinder – type extraction vessels and mushroom – type extraction vessels can be used as static extraction vessels, and can also be equipped with different stirrers to serve as dynamic extraction vessels.

Static extraction vessels are lower in height than dynamic extraction vessels, making them suitable for factories with limited plant height. Although they are not equipped with stirrers, the extraction efficiency and yield can be improved by increasing the heating temperature, forced circulation of pumps, direct steam injection into the slag discharge door and other methods.

A complete set of static extraction vessels mainly consists of seven components: main tank (extraction tank), foam trap and defoamer, condenser, cooler, oil-water separator, filter, and pump. The extraction tank, as the main tank, is the core equipment for extraction reactions, where processes such as raw material cooking, heating, cooling, evaporation, reflux, and oil removal are carried out. The extraction tank generally adopts a rotary locking slag discharge door for discharging, which is convenient, efficient, and safe. The top of the foam trap is equipped with a quick-opening structure to facilitate the disassembly of the defoaming structure, and the built-in defoaming structure is easy to disassemble and clean. The condenser, cooler, vapor-liquid separator, filter, etc., are designed according to actual conditions such as working pressure, heat exchange area, shell side wall thickness, and tube specifications.

Static extraction vessels are equipped with CIP cleaning automatic rotating cleaning balls, real-time online temperature display, pressure gauges, explosion-proof sight lights, sight glasses, quick-opening feeding ports, etc., ensuring easy operation and compliance with GMP standards. The inner cylinder of the equipment is made of high-quality stainless steel SUS304 or SUS316L. The insulation medium adopts aluminum silicate/rock wool/polyurethane, etc., and the insulation medium is covered with stainless steel cladding, which is beautiful and elegant.

After completing the preliminary preparations, put the medicinal materials into the tank through the feeding port at the top of the tank. Open the water inlet valve and add an appropriate amount of water (or organic solvent, the same below) according to the preparation process requirements, which is usually about 5-8 times the amount of the medicinal materials. A certain amount of space should be left in the tank after adding the medicinal materials and water.

Turn on the steam for the heating jacket of the extraction tank. If rapid heating is required, the direct steam valve can be opened simultaneously to quickly heat the contents to boiling. After the solution in the tank boils, the solution vapor, carrying aromatic oils with lower boiling points, rises to the condenser and then flows through the cooler to the oil-water separator. Based on the principle of different specific gravities of oil and water, the aromatic oils are separated and collected for later use. After most of the oil has been collected, return the solvent in the oil-water separator to the extraction tank to maintain the solution volume in the tank. The boiling time for the first extraction is approximately 2 hours. After the first extraction is completed, turn off the steam. Open the liquid discharge valve and pump the extract from the tank through the filter to the storage tank.

Add solution for the second extraction and proceed as in the first extraction for about 1 hour and 30 minutes, then combine the liquid with the first extraction. Add solution for the third extraction and proceed similarly for 40 minutes to 1 hour, then combine all three extracts. When the solution in the extraction tank becomes colorless (indicating that most of the active ingredients have been extracted), allow the residual liquid to drain naturally, then open the slag discharge door to remove the medicinal residues. If ethanol is used as the extraction solvent, after filtering the liquid from the third extraction, add an appropriate amount of water, turn on the steam to recover the ethanol solvent for use in subsequent batches, and then remove the medicinal residues. After removing the medicinal residues, open the cleaning valve for in-place cleaning (CIP). After cleaning, close the discharge door to prepare for the next batch of materials.