Mixed solvent low-pressure fluid critical extract method

Abstract

The invention relates to a method for critically extracting component solvent low pressure fluid, which comprises extraction, separation and solvent recovery. The method is characterized in that 75-95 wt% of 1, 1, 1, 2-tetrafluoroethane and 5-25 wt% of normal butane are taken as component solvent; in the extracting process, the component solvent is controlled to be in a liquid to be contacted with materials to lead the active ingredients of the materials to be dissolved in the liquid component solvent; in the separating process, the component solvent is controlled to be in a gas state and separated from the extracted liquid active ingredients; the separated component solvent is compressed and cooled to become liquid in a mixed state, and then is recovered for cyclic utilization; and the steps of extraction, separation and solvent recovery are carried out in a sealing state at the same time. The operating pressure and the manufacturing cost of the equipment are both lower than those of a carbon dioxide supercritical extraction method; the GWP of the component solvent is lower than that of the 1, 1, 1, 2-tetrafluoroethane, so that the method of the invention is in accordance with environmental requirements, is low in price and has high extraction efficiency.

Description

technical field [0001] The invention relates to a mixed solvent low-pressure fluid critical extraction method. It is especially suitable for the extraction of active ingredients contained in natural plants and Chinese herbal medicines. Background technique [0002] Traditional methods for extracting active ingredients from natural plants and Chinese herbal medicines include steam distillation, vacuum distillation, and solvent extraction. The disadvantages of the traditional method are complex process, time-consuming, great environmental pollution, low product purity and easy residue of harmful substances. Although the carbon dioxide supercritical extraction method that has emerged in recent years can produce high-purity products with specific properties, it is difficult to achieve large-scale production due to high operating pressure (10-60Mpa) and expensive equipment manufacturing costs. Chinese patent application number 200610070495.0 discloses "a low-pressure supercriti...

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Problems solved by technology

The disadvantages of the traditional method are complex process, time-consuming, large environmental pollution, low product purity and easy residue of harmful substances

The carbon dioxide supercritical extraction method that has emerged in recent years can produce high-purity products with specific properties, but the operating pressure is high (10-60Mpa) and the equipment manufacturing cost is expensive, making it difficult to achieve large-scale production

Chinese patent application number 200610070495.0 discloses "a low-pressure supercritical extraction process and its equipment", which uses 1,1,1,2-tetrafluoroethane tetrafluoroethane (chemical code HFC-134a) as the critical extraction Solvent, although its operating pressure is lower than the carbon dioxide supercritical extraction method, but because 1,1,1,2-tetrafluoroethane is a greenhouse gas, it can block infrared radiation from returning to the sky, and has a direct impact on global warming. Its global warming potential value GWP is as high as 1300, so its emission (emission), use, and production are subject to strict international controls; moreover, the unit price of industrial-grade 1,1,1,2-tetrafluoroethane is higher than food-grade carbon dioxide More than 50 times, used as an extractant, the production cost is high, which is also unacceptable for enterprises in industrial production

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