Device and method for extracting essential oil from medicinal materials by utilizing supercritical sulfur hexafluoride

Abstract

The invention discloses a device and a method for extracting essential oil from medicinal materials by using supercritical sulfur hexafluoride, and relates to the technical field of traditional Chinese medicine extraction and refining, and the device comprises a supercritical fluid extraction system and a vacuum drying system. Wherein the supercritical fluid extraction system comprises a sulfur hexafluoride gas storage bottle, a filter, a dryer, a cooling tank, a flow meter, a high-pressure pump, a heat pipe heat exchanger, an extraction kettle, a throttling pressure reducing valve and a precipitation bin, and is mainly used for extracting essential oil from dried and crushed medicinal materials; the vacuum drying system comprises a water storage tank, a circulating pump, a vacuum drying box, a regulating valve, a vacuum pump and a heat conduction pipe and is mainly used for drying raw materials before essential oil extraction; the vacuum drying system is connected with a precipitation bin in the supercritical fluid extraction system through a heat conduction pipe to realize high-temperature waste heat recovery; and secondary high-temperature waste heat in the vacuum drying system is recycled through the heat pipe and used for preheating supercritical sulfur hexafluoride, and gradient utilization of heat energy can be achieved.

Description

technical field [0001] The invention relates to the technical field of extraction and purification of traditional Chinese medicines, in particular to a device and a method for extracting essential oils from medicinal materials by using supercritical sulfur hexafluoride. Background technique [0002] Essential oils refer to volatile aromatic substances extracted from the roots, stems, leaves, flowers, fruits, seeds, bark, wood hearts and other parts of plants by physical or chemical methods; the medicinal use of plant essential oils has a long history. It has a wide range of applications in the human olfactory nerve, skin system, respiratory system, digestive system, endocrine system and reproductive system, and is an important component of traditional Chinese medicine. [0003] At present, there are many methods for preparing essential oils, mainly including steam distillation, cold pressing, dry distillation, liposuction or solvent extraction; but these methods all have lim...

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Problems solved by technology

[0003] At present, there are many methods for preparing essential oils, mainly including steam distillation, cold pressing, dry distillation, fat absorption or solvent extraction; but these methods have limitations to varying degrees or extraction time is too long, or extraction The efficiency is too low, or the purity of the finished product is not good

[0004] Due to its liquid-like solubility and gas-like fluidity, supercritical fluid is widely used in the extraction and separation of various substances; in the current common supercritical fluid preparation methods, carbon dioxide and water are mostly used as extraction agents, but their The supercritical condition is too high (the critical temperature of water is 374.15°C and the critical pressure is 22.13MPa; although the critical temperature of carbon dioxide is low at 31.26°C, but the critical pressure is high at 7.3MPa), the energy consumption is large and there are hidden dangers ; Ethanol, ethane, ammonia water, etc. are used as supercritical media. Although the critical conditions are relatively low, most of these substances are flammable, explosive or toxic

[0005] Sulfur hexafluoride, the chemical formula is SF 6 , is a colorless, odorless, non-toxic, non-combustible stable gas, its density is about 5 times that of air (density and solvency are positively correlated), critical temperature is 45.6 ℃, critical pressure is 3.76 MPa, as a This greenhouse gas is easy to obtain and low in price; sulfur hexafluoride has good solubility for low polar oil compounds, and due to the high density, low viscosity and low supercritical conditions of sulfur hexafluoride, it is different from traditional Compared with the use of carbon dioxide or water as the extraction agent, the volume of the equipment is greatly reduced, the production cost is reduced, and the safety of the equipment is greatly improved, but there are few reports on related technical equipment at present.

At the same time, most of the existing supercritical fluid extraction equipment does not consider the cascade utilization of waste heat in the precipitation chamber. The waste heat in the precipitation chamber of supercritical extraction equipment can be used for drying and preheating of supercritical fluid in turn. In the environment of energy saving and emission reduction Only by realizing cascade utilization of energy can the limited resources be used more effectively

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