CO2 extraction process
As a green technology, the supercritical CO2 extraction process has been widely used in the extraction and separation of active ingredients of natural products. The industrial-scale annual production capacity ranges from hundreds of tons to tens of thousands of tons.
However, the conventional supercritical CO2 extraction has only one-stage separation in theory. When separating and purifying liquid mixtures, the efficiency is very low.It is especially difficult to separate and purify the components in the mixture with small differences in properties.
Supercritical Fluid Fractionation SFF
The supercritical CO2 countercurrent extraction technology ( Supercritical Fluid Fractionation SFF) uses the raw material components in the extraction tower to undergo multiple differential contact extractions with CO2, and through multi-stage separation, the separation and purification of components with small differences in properties is achieved.
However, continuous supercritical CO2 countercurrent extraction ( Supercritical Fluid Fractionation SFF) technology lags far behind the development of supercritical CO2 extraction technology.
This article introduces the research status of supercritical CO2 countercurrent extraction ( Supercritical Fluid Fractionation SFF) technology, and reports on the industrial scale continuous supercritical CO2 countercurrent extraction technology to concentrate pepper pigments.
As a result, the application prospect of this technology in the separation and purification of ginger oil, lemon oil, citrus oil and other spices is also prospected.
CO2 countercurrent extraction process
Continuous countercurrent supercritical CO2 extraction (Continuous countercurrent supercritical CO2 extraction, CC-SCE) is an effective way to achieve continuous operation of liquid materials.
The countercurrent extraction process carried out in the tower equipment is the differential contact extraction process, and the CO2 phase fills the entire tower.
In the continuous phase, the raw materials are distributed in the continuous phase in the form of droplets, which is the dispersed phase. The CO2 phase is added at the bottom of the tower and led out from the top of the tower; the raw materials enter from the top or side of the tower, and the raffinate is collected from the bottom of the tower.
The two phases flow countercurrently along the axis of the tower, and the supercritical CO2 is transferred to the liquid material. At the same time, in the presence of a temperature gradient, the solute can form an internal reflux, just like distillation. After a multi-stage equilibrium of dissolution-precipitation-dissolution, the solute will enter the separator with CO2 from the top of the tower for separation and collection. Feeding and discharging are automatically controlled by high-pressure pumps and valves.
The continuous operation of the extraction process greatly increases the processing capacity of the equipment, reduces process energy and gas consumption, and reduces production costs; in addition, materials and supercritical CO2 pass through the packing in the tower Or the trays are used for mass transfer, and the number of theoretical trays is high, which can effectively separate and purify the mixed liquid with small separation factor and difficult to separate.
CO2 extraction process of pepper pigment
CO2 extraction process
The pilot test is based on capsicum pigment with a color value of 24000 as the raw material, the countercurrent extraction tower is 6 meters high, the raw material feed rate varies between 500-1000g/h, the CO2 flow rate is set to 20-60kg/hr, and the temperature distribution It is 35-50℃, and the pressure is 25-32MPa.
The increase in pressure and CO2 flow rate are beneficial to improve the color gradation.
Industrial scale test resultsOn the basis of the pilot test, a set of industrial-scale continuous supercritical CO2 countercurrent extraction device was established.
The annual processing capacity of pepper pigment is 600 tons, the color price of pepper pigment is 24,000, and the CO2 flow rate is 30000 M3/h M2, and the pressure is Under 36MPa, the color price of pepper pigment increased by more than 6 times, up to 150,000.
CO2 extraction process VS CO2 fractionation
Compared with the results of supercritical CO2 extraction, under the same volume of autoclave and processing capacity, the countercurrent treatment time is only half of the traditional treatment time, and the color value concentration factor of the countercurrent extraction product is much greater than that of the first stage extraction.
It can be seen that the countercurrent extraction process greatly improves the production efficiency of the equipment, reduces the production cost, and has high practical value.
The supercritical CO2 countercurrent extraction technology has important application value in the separation, concentration and purification of liquid materials.
It has achieved good results in the separation and purification of ginger oil, lemon oil, citrus oil and other spices. It has a wide application prospect.
This technology can not only separate Concentrate and purify natural fragrances, plant essential oils, natural pigments, fish oil actives, natural VE and other natural active heat-sensitive materials, and have important practical significance for decolorizing, deodorizing, removing residual solvents, and removing pesticide residues of liquid materials.