New pilot installations of extraction equipment equipment with fluent supercríticos

The CO₂ in conditions supercríticas (above 31°C and of 74 bar) presents a high density, solubility and high coefficients of transfer of matter. Besides, in these conditions his viscosidad is very low. This does that his solvent capacity was very high.

When the current of CO₂ in these conditions crosses a mulch of product, the component of interest is extracted of a simple way and, in the majority of the cases, without the utilisation of dissolvent whose back elimination is difficult and costly.

Later produces a despresurización so that the CO₂ happens of state supercrítico to gaseous state with what loses his solvent power and in this loose ‘expansion' the product extracted in the previous stage. It can be necessary, depending of the process, one or vary stages of fractionation to different pressesures.

Finally the CO₂ is recirculado by means of a process in which it takes part one or several filters to delete part of the product that could have dragged the carbon dioxide and a condensation to store the same in liquid state and so that it can be pumped again to the plant to the pressesure in which the extraction equipment equipment takes place.

To continuation presents a typical diagram of this type of installations:

In the greater part of the cases the extraction equipment equipments produce between 200-350 bar of pressesure and to inferior temperatures to 80°C. This technology is, therefore, very adapted for products termo sensitive.

Usually is necessary to elaborate a protocol of proofs together with the customer, to determine which conditions (pressesure, temperature, dissolvent relation/product, etc…) are the most adapted for a determinate process.

The peculiarities of design of this type of plants are mainly related with:

- High pressesures of operation.

- Specific properties of the carbon dioxide.

High pressesures of operation

The high pressesures of work translate in some thicknesses of high equipment. This is one of the main reasons of the high initial investment that suppose these plants. Many times it is necessary the optimisation of the material and his availability in the market to be able to evaluate the most economic option.

On the other hand, the enclosures used, mainly in the plants of solids that work in way batch or semi-continuous, are of complex design since they have to be safe in addition to guaranteeing the closing in the conditions of operation. Also they have to be easy to handle by operarios in case of installations of small size or through hoists for industrial sizes.

Another very important point to take into account in the design of these plants are all the systems hygiene associated to these high pressesures of operation, that is to say, valves of hygiene, disks of split, sequences computerised of start and unemployed and a group of enclavamientos and alarms allocated to realise always the operations of a safe form.

The specific properties of the CO₂ do that it was necessary to have special care to the hour of the design.

Exotermia: In the despresurizaciones produces an exotermia that has to be neutralised by means of the corresponding contribution of heat, since but produces the learning of carbonaceous snow that it can obturar the pipes and even damage the interns of the valves of control because of the solidifications in the interior of the same.

Abrasion: The so elevated difference of pressesures between some points and others of the plant does that the carbon dioxide can go to big speed between two points causing problems of abrasion, so much in the interns of valves (manual and of control) as in the boards. The Vitón is one of the elastomers that never has to be used in these applications.

Alimentary industry: Are multiple the applications inside the alimentary industry because of the low temperatures of work and to avoid the classical extraction equipment equipment with dissolvent: desalcolización of the wine, elimination of the teína of the tea, elimination of the caffeine of the coffee, obtaining of vegetal extracts (thyme, romero, pimiento), fractionation of oils, etc…

pharmaceutical Industry: Purificación of active principles, extraction equipment equipment of ingredients of natural origin, etc…

cosmetic Industry: Obtaining of ingredients of natural origin, elimination of aromas, etc…

• moderate Temperatures of extraction equipment equipment (60-80 °C)→Adapted for products termo sensitive.
• Obtaining of extracts and refinados without traces of dissolvent.
• No broadcast of volatile organic compounds to the atmosphere.
• Installations NO ATEX.
• To the not having presence of oxygen avoid reactions of oxidation.
• Possibility to vary qualities of extract and refinado varying conditions of operation of simple form.