PT116340B - PROCESS AND SYSTEM FOR EXTRACTING 2,4,6-TRICHLOROANISOLE (TCA) FROM CORK MATERIAL - Google Patents

Abstract

THE PRESENT INVENTION REFERS TO A PROCESS AND SYSTEM FOR DECONTAMINATION OF CORK MATERIAL. THE PROCESS INCLUDES CYCLICALLY CIRCULATION OF AN EXTRACTION FLUID THROUGH A BED OF CORK MATERIAL, FOLLOWED BY CIRCULATING THE FLUID THROUGH AN ADSORBENT MEDIUM TO REGENERATE THE EXTRACTION FLUID AND RETURN THE FLUID THUS REGENERATED TO THE CORK BED, REPEATING THE SAME CIRCULATION OF FLUID DURING A PREDETERMINED AMOUNT OF TIME, IN WHICH THE REGENERATION STEP OF THE EXTRACTION FLUID IS CARRIED OUT IN SUPERCRITICAL OR NEAR-CRITICAL CONDITIONS OF PRESSURE AND TEMPERATURE FOR THE EXTRACTION FLUID. THE INVENTION ALSO REFERS TO A SYSTEM FOR PERFORMING THE PROCESS OF DECONTAMINATION OF CORK, THE SYSTEM COMPRISING A PUMPING MEANS (2) TO CIRCULATE THE EXTRACTION FLUID, AND A MEANS TO SUPPORT CORK MATERIAL (4), BOTH ARRANGEMENTS INSIDE FROM AN EXTRACTION CHAMBER (1). IN A PREFERRED EMBODIMENT, AN ADSORBENT MEDIUM SUPPORT (3) IS ALSO ARRANGED IN SERIES INSIDE THE EXTRACTION CHAMBER (1). THE INVENTION APPLIES TO THE CORK INDUSTRY.

Description

PROCESS AND SYSTEM. FOR EXTRACTION OF 2,4,6-TRICHLOROANISOLE (TCA) FROM MATERIAL

OF CORK

FIELD OF THE INVENTION

The present invention relates to a process and system for decontaminating cork material using a cycle comprising a step of extracting contaminating compounds from cork material and only one step of regenerating the extraction fluid. The invention applies to the cork industry.

Λ Τ'Λ.Τί

The decontamination of cork material is of extreme importance in the cork industry, particularly in relation to the production of cork stoppers to be used to close beverage bottles, and especially wine bottles.

It is well known that cork is a natural product originating from the cork oak tree that has desirable natural characteristics for a number of different uses and that it is currently spread worldwide under a variety of different commercial products, namely from the food, aeronautics, flooring and construction industries, among others. many others.

Cork stoppers to close or seal wine bottles are one of the main applications for cork material.

Its elasticity and impermeability to liquids, in addition to its low permeability to gases, make it a unique environmentally friendly material for this application.

In addition to providing efficient closure/sealing of bottles, stoppers made from cork also contribute to proper maturation or aging of wine when bottles are stored for long periods of time. This is not achieved by stoppers made from other materials.

However, given its nature, the cork material naturally contains some natural compounds that act as contaminants in food items, in particular wine. In fact, these substances are responsible for adulterating the taste and aroma of food items. These harmful effects are known to taste like a wine cork.

Examples of such contaminating compounds are 2,4,6-trichloroanisole (TCA), 2,4-dichloroanisole, 2,6-dichloroanisole, 2,4,6-tribromoanisole (TBA), 2,3,4, 6-tetra -chloroanisole (TeCA), pentachloroanisole (PCA), 2,4,6-trichlorophenol (TCP), 2-methylisoborneol (MIB), geosmin, 2-isobutyl-3-methoxypyrazine (IBMP), 2-isopropyl-3-methoxypyrazine (IPMP) , 2-methoxy-3,5-dimethylpyrazine (2M35DP), guaiacol, l-octen-3-ol, and l-octen-3-one, to name just a few.

Since the presence of such contaminants is quite detrimental to the organoleptic properties of beverages, especially affecting wine, the cork industry has made considerable efforts to develop appropriate solutions to remove said contaminants from cork material.

One widely used solution is the use of dense fluid circulation loops, particularly under supercritical conditions, which is known in the art as Supercritical Fluid Extraction or SFE.

Usually, conventional processes based on SFE resort to a) circulating an extraction fluid under supercritical or near-critical conditions through a bed of cork, thus solubilizing the contaminating extractable compounds; then b) the extraction fluid containing contaminants is subjected to a decompression well below the critical pressure, so that the fluid becomes a compressed gas with drastically reduced solvent capacity and, for this reason, the solutes (contaminants) precipitate in a vessel collection (in some cases, after precipitation, the extraction fluid is further circulated through a filtration medium, for example an adsorbent material such as activated carbon, to better regenerate the extraction fluid); then c) the already regenerated extraction fluid is cooled to condense to liquid state and is pumped and heated to the desired (supercritical or quasi-critical) conditions of step a) and the cycle continues by carrying out steps a) to c) again. The cycle is carried out for a certain period of time depending on the amount and type of cork material to be treated (Fig. 2 illustrates a conventional cycle of this type).

This conventional cycle has a number of important drawbacks:

• Intensive energy consumption due to the cooling and heating steps included in each cycle;

® Intensive energy consumption due to the necessary pressure drop and recompression steps in each cycle;

• High fixed capital costs due to heat exchangers, condenser, separator and pump required within the cycle; and o High maintenance costs derived from the complex systems that are inevitably needed to carry out the process.

A number of variants to this solution may include more or less extraction fluid regeneration steps, and more complicated compression-decompression and/or fluid heating-cooling steps, while maintaining the above-mentioned core core steps.

European patent EP 1216123 B2, entitled Method For Treating And Extracting Cork. Organic Compounds, With A Dense Fluid Under Pressure, discloses a method for treating cork or a cork-based material, to extract contaminating organic compounds therefrom, which consists of contacting the cork or the said cork-based materials with a dense fluid under pressure, at a temperature between 10 and 120 °C and under a. pressure from 1xlO ⁶ to 60xl0 ^s Pa.

European patent EP 1701775 B2, entitled A Method And Process For Controlling The Temperature, Pressure And. Density Profiles In Dense Fluid Processes And Associated Apparatus, discloses a method of treating a material contained in a vessel. This method involves a fluid present in the vessel and comprises at least one pressurization step, where the pressure in the vessel is increased, and at least one depressurization step, where the pressure in the vessel is decreased. The invention also relates to a device for carrying out this method and the products obtained therefrom.

The European patent. EP 2396153 Bl, entitled Method For Direct Treatment Of Cork Stoppers, Using Supercritical Fluids, discloses a method that allows the direct treatment of natural cork stoppers, using supercritical fluids with the aim of eliminating or significantly reducing the. amount of cork contaminants, namely 2,4,6-trichloroanisole. The process uses a separating device that allows natural cork stoppers to undergo compression/decompression cycles without losing their shape and maintaining their sealing properties.

European patent EP 2404647 Bl, entitled Method For Extracting Organic Compounds From Granulated Cork, discloses the extraction of organic compounds present in granulated cork by dispersive application of a supercritical fluid comprising at least two different gases in a supercritical state. This can be combined with a previous extraction using continuous steam carried out in another extractor. Each extractor is also supported on a vibrating base, through which a more uniform contact of the steam or supercritical fluid with the granulated cork is obtained.

The gases from the extraction are recirculated through several recirculation circuits to make better use of the gases. One of the components that make up the recirculation is a condenser with a conical body, which provides a larger surface for evaporating the coolant and thus increases the condensation of gases.

European patent application 2799199 A1, entitled Method For Removing Various Undesirabie Compounds From Cork, discloses a method for removing compounds which are responsible for undesirable tastes and/or odors, such as phenolic compounds or anisole derivatives, the method comprising keeping the cork to be treated at a pressure between 6.4xl0 ⁶ and 45xl0 ⁶ Pa, a temperature between 27 °C and 90 °C and doing so for a period of time of less than 60 minutes, only in contact with a dense gas, without additional co-solvents or coagulating substances other than said dense gas. The method can include several regeneration steps to regenerate the fluid.

international application published as WO2005025825, entitled Method For The Extraction Of Cork-Containing Material, discloses a method for extracting material containing cork with the aid of a compressed gas at temperatures ranging between 10 and 120 ^C C and pressures ranging from 1x10 ⁶ and 60x10® Pa. Extraction takes place under isobaric conditions, while compressed gas flows through the charge in a radial or axial direction and the charge which is to be extracted is combined with an adsorbent material. The inventive method allows cork boards, cork granules, cork stoppers, or agglomerated cork, for example, to be quantitatively removed from organic compounds, such as pentachlorophenol, trichloroanisole and tetrachloroanisole, as well as waxes and fats so that materials containing purified cork can be used unreservedly in the food sector and particularly in the beverage sector.

Although the aforementioned processes may be more or less effective in terms of removing contaminants from cork, they all suffer from the inconvenience of requiring complex systems to be implemented. On an industrial scale, such complexity implies large amounts of equipment, energy and maintenance costs.

On the other hand, the compression-decompression cycles of conventional treatment continuously dry the cork material throughout the cycle's operating time, with serious consequences for its structural integrity. In fact, the imposed pressure drop can decrease the solubility of the . water in the extraction fluid, causing a. its condensation in the collection vessel. In this way, the water that is transferred from the cork material to the extraction fluid (cork drying) is subsequently eliminated in the collection vessel by condensation.

Furthermore, the particular elimination of larger molecules (e.g., long-chain aliphatic alcohols, waxes and fats) from the extraction fluid requires dedicated equipment and specific thermodynamic conditions to reduce their solubility and promote a. its precipitation, thus making the process and the respective systems complex to implement and maintain.

Accordingly, there is a need in the art for an SFE-based process system that overcomes the aforementioned drawbacks.

SUMMARY OF THE INVENTION

The present invention relates to a process for decontaminating cork material, the process comprising the steps of:

a) Circulate a supercritical or quasi-critical extraction fluid through a batch of cork material in order to extract contaminating compounds from the cork by solubilizing them in the extraction fluid; followed by

b) circulating in supercritical or quasi-critical conditions of pressure and temperature the extraction fluid containing contaminants from step a) through an adsorbent medium, in order to eliminate the contaminants from the extraction fluid by adsorption; followed by

c) repeat step a) with the extraction fluid regenerated from step b); It is

d) repeating steps b) and c) for a predetermined period of time.

In one embodiment, steps a) and b) of the process comprise circulating the extraction fluid at the same pressure in both steps a) and b).

In a preferred embodiment, steps a) and b) of the process comprise circulating the extraction fluid at the same pressure and at the same temperature in both steps a) and b).

Preferably, step b) of the process of the invention comprises circulating the extraction fluid containing contaminants through an adsorbent medium selected from the group comprising activated charcoal, clays, diatomaceous earth, a zeolite material, silica gel, resins, and their combinations; more preferably, circulating the contaminant-laden extraction fluid through activated carbon.

In another. In the preferred embodiment, step b) of the process of the invention comprises circulating the extraction fluid containing contaminants through an amount of activated carbon in the range of 1.5% to 8% by weight of the cork material, preferably 2 % to 5%, more preferably 2.5%.

Preferably, steps a) and b) of the process of the invention comprise circulating CO2 as the extraction fluid, more preferably, steps a) and b) comprise circulating water mixed with COz, the water in the range of 0 .05% w/w until saturation.

In a further embodiment, steps a) and b) of the invention comprise circulating CO2 at a pressure in the range of 6x10 ⁶ preferably 7x10 ⁶ to 15x10 ⁶ Pa, more preferably process at 30x10 ⁶ Pa, 10x10 ⁶ Shovel.

In another embodiment, steps a) and b) of the process of the invention comprise circulating CO2 at a temperature in the range of 20°C to 160°C, preferably 30°C to 90°C, more preferably 0°C to 80°C, most preferably 60°C.

In a further preferred embodiment, the process of the invention comprises: a) circulating a mixture of CO2 saturated with water, at 10x10 ^s Pa and 60°C, through a batch of granulated cork followed by b) circulating the CO2 saturated with water and containing contaminants through a bed of activated carbon under the same pressure and temperature conditions as in step a); followed by repeating step a) with CO2 saturated with water and free of contaminants from step b); and repeat the cycle for 30 minutes, where the mass of activated carbon is 2.5% of the mass of granulated cork, and the mass of granulated cork is 14% of the mass of circulated CO2.

The invention also relates to a system for carrying out the process of the invention, the system comprising:

® an extraction chamber (1) ;

• a pumping means (2) for circulating an extraction fluid;

• an adsorbent medium support (3) for supporting an adsorbent medium; and ® a support means of cork material (4) arranged inside the extraction chamber (1), characterized in that said pumping means (2) is arranged inside the extraction chamber (1).

Preferably, said adsorbent medium support (3) is also arranged inside the extraction chamber (1).

In one embodiment, the system further comprises three compartments within the extraction chamber (1), said compartments being interconnected for fluid circulation, but separated for solids, in which each compartment respectively contains the pumping medium (2), the adsorbent medium support (3), and cork material support medium (4)·

Preferably, said three compartments are arranged in series in any order, more preferably, said compartments are arranged in the order of pumping medium compartment, adsorbent medium support compartment and water support medium compartment. cork material.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of the invention is provided below, with reference to the accompanying drawings, in which:

Fig. 1 illustrates an example of a phase diagram in which pressure-temperature equilibrium is shown in terms of reduced properties;

Fig. 2 is a schematic representation of a common prior art supercritical fluid (SFE) extraction process, showing a conventional operating cycle and the respective pressure and temperature variations throughout the cycle, the horizontal stripe with textured pattern represents the possible range pressure and temperature conditions in which the extraction fluid remains in a supercritical or near-critical state; where: P Pressure; T- Temperature; A, Cl, C2 - heat exchangers; BI - pump; D extractor; E - decompression valve; F - collection vessel; G - filtration medium G; the ordinate axis indicates the temperature and pressure variation over a cycle of the extraction process and the abscissa axis indicates the stage of the process cycle.

Fig. 3 is a schematic representation of the SFE process of the present invention, showing the operating cycle of the invention and respective pressure and temperature variations throughout the cycle, the horizontal band with textured pattern represents the possible range of pressure and temperature conditions in which the extraction fluid remains in a supercritical or near-critical state; where: P - Pressure; T- Temperature; B2 - fan; D - extractor; G - adsorbent medium; C3 - heat exchanger; the ordinate axis indicates the temperature and pressure variation over a cycle of the extraction process and the abscissa axis indicates the stage of the process cycle.

Fig.

a schematic illustration of a preferred embodiment of an inventive system for carrying out the process of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a process and system for extracting contaminating compounds from cork material.

The invention is specifically directed to a supercritical fluid extraction (SFE) process that makes use of a cycle with an extraction fluid operating in its supercritical or near-critical pressure and temperature conditions, thus operating in a supercritical or near-critical state. critical.

In the context of the present invention, an extraction fluid in a supercritical or near-critical state is hereinafter simply referred to as a supercritical extraction fluid, unless explicitly mentioned otherwise.

supercritical state corresponds to the region of a well-known pressure-temperature equilibrium diagram (or phase diagram - see Fig. 1) where the fluid is simultaneously above its critical temperature and critical pressure: T>Tc and P>Pc. When a fluid is in the supercritical state it is usually referred to as a supercritical fluid. The critical pressure and the critical temperature are characteristic of each fluid, for example, for carbon dioxide these correspond to 7.38x10® Pa and 31.1 °C. Naturally, each fluid has its own diagram. of phases.

With reference to Fig. 1, it should be noted that another way of defining the supercritical region is in terms of reduced properties, which are the ratios between the property values and their values at the critical point (eg _r Pr=P/Pc and Tr=T/Tc ). Thus, a supercritical fluid is defined as a fluid with Pr>le Tr>l.

Still referring to Fig. 1, a quasi-critical fluid is a fluid whose pressure and temperature conditions are within the quasi-critical region. This region can be arbitrarily defined around the critical point in a pressure-temperature diagram as 0.9<Pr<l,l and 0.9<Tr<l,1.

A subcritical fluid or subcritical region is an arbitrary region where at least the temperature or pressure is below its critical value, i. e., 0.9<Tr<1 and 0.9<Pr; or 0.9<Pr<1 and 0.9<Tr.

For the simplicity of the description, by supercritical extraction fluid is to be understood an extraction fluid that is in a supercritical or near-critical state according to the above definition.

In fact, this means that there is a small range of variation slightly below the so-called critical conditions of pressure and temperature in which the dense fluid still retains the capacity to perform the extraction function and, for this reason, such variation must be considered and understood. in the operating range of the fluid. This understanding is not new and is well accepted and described in the prior art, namely in some prior art cited herein.

Various fluids have been used under supercritical conditions in various applications, both singly and in combination (in the case of admissible mixtures). Carbon dioxide (hereinafter simply referred to as CO2) is the preferred solvent for supercritical extraction as it has been proven to be safe, inert, non-toxic, non-flammable, non-explosive, and has a relatively easy to reach critical point: 7 ,38x10®

Shovel

The properties of a pure supercritical fluid, e.g. g ., solvent capacity or selectivity for target compounds can be improved by mixing small amounts of an inorganic or organic solvent, which is called a co-solvent or modifier. Water and ethanol are the most commonly used co-solvents.

If the temperature and pressure are above the critical temperature of the critical pressure of the binary mixture, the fluid (mixture) is under supercritical conditions and, as such, can be used as an extraction fluid.

A mixture of CO2 with small amounts of water, from 0.05% w/w to saturation, is a preferred extraction fluid of the present invention, as the presence of water will have a positive impact on maintaining the moisture content. suitable in cork material.

The present invention provides a cork material process.

for decontamination of

The cork material to be decontaminated is selected from the group comprising cork powder, granulated cork, cork stoppers, cork planks and cork boards.

The present invention is directed to the decontamination of cork material, thus, in general, any cork-based material or composite material containing cork can be subjected to the process and system of the invention, provided that such material can withstand the conditions of pressure and process temperature without compromising yours. structural integrity.

The most common contaminants extracted with the process of the present invention are 2,4,6-trichloroanisole (TCA), 2,4-dichloroanisole, 2,6-dichloroanisole, 2,4,6-tribromoanisole (TBA), 2,3,4, 6-tetrachloroanisole (TeCA), pentachloroanisole (PCA), 2,4,6-trichlorophenol (TCP), 2-methylisoborneol (MIB), geosmin, 2-isobutyl-3-methoxypyrazine (IBMP), 2-isopropyl-3-methoxypyrazine (IPMP), 2-methoxy-3,5-dimethylpyrazine (2M35DP), guaiacol, 1-octen-3-ol, and 1-octen-3-one. In addition, sterols, triterpenoids, long-chain aliphatic alcohols, waxes and fats present in cork are also extracted.

For a detailed understanding of the invention, a brief description of the conventional processes and systems most used in the prior art is described below with reference to Fig. two.

In order to put into practice the prior art cycle of Fig. 2 a system comprising the following parts is used: heat exchangers (A, Cl, C2), pump (Bl), extractor (D), pressure relief valve (E), collection vessel (F) and filtration medium (G ).

In summary, this prior art loop comprises (see Fig. 2):

® Circulate the supercritical extraction fluid through the extractor (D) containing the cork to be treated, the extractable compounds (contaminants) are solubilized in the extraction fluid; then • the fluid circulates through a decompression valve (E) where it significantly reduces its pressure, well below the critical pressure. At this point, the fluid can also be heated in a heat exchanger (C2) to compensate for the drastic cooling of the decompression in order to prevent freezing and clogging of the pipe;

® at this lower pressure, the fluid is in the state of compressed gas and its solvent capacity drastically decreases, and the solutes (contaminating compounds plus other extractable compounds such as sterols, triterpenoids, long-chain aliphatic alcohols, waxes and fats above mentioned) precipitate in the collection vessel (F). Optionally, in some cases, after the precipitation step, the extraction fluid is further passed through a filtration medium (G), for example an adsorbent bed of activated carbon, to remove non-precipitated contaminants that may still exist, from in order to further purify the extraction fluid; then • the regenerated extraction fluid is cooled and liquefied by means of a heat exchanger (A); the liquefied fluid is then pumped by a pump (Bl) to the desired high extraction pressure (above the critical pressure); and finally, the extraction fluid is heated (Cl) to the operating temperature (above the critical temperature);

® at this point, the fluid is again in the supercritical state and the cycle restarts.

When the time defined for the cycle ends, the entire system is depressurized to remove the cork material (decontaminated) and load it with another bed of cork to be decontaminated.

In this prior art process, the step of (fluid expansion to a) precipitation of contaminating compounds is a key factor in a. continuity of the cycle, since the extraction fluid has to be regenerated (purified) before a new solubilization step of the contaminating compounds occurs, otherwise a. process efficiency does not fit the requirements of said industrial process. More regeneration steps, such as one using an adsorbent medium, for example activated carbon, were considered complementary in the art and were used to further improve fluid regeneration.

Relevant drawbacks with respect to the above prior art process are mentioned in the Background of the Invention section above. It is obvious that significant energy and equipment costs are involved in the steps of repressurizing and reheating the fluid to its operating conditions.

The process of the present invention does not resort to a fluid expansion step (which involves a significant pressure drop) for the precipitation of contaminating compounds to regenerate the extraction fluid.

The process of the present invention for decontaminating cork material comprises the steps of:

a) Circulate a supercritical or quasi-critical extraction fluid through a batch of cork material in order to extract contaminating compounds from the cork by solubilizing them in the extraction fluid; followed by

b) circulating in supercritical or quasi-critical conditions of pressure and temperature the extraction fluid containing contaminants from step a) through an adsorbent medium in order to eliminate the contaminants from the extraction fluid by adsorption; followed by

c) repeat step a) with the extraction fluid regenerated from step b); It is

d) repeating steps b) and c) for a predetermined period of time.

Surprisingly, it has been found that a cyclic process comprising a single fluid regeneration step in the supercritical (or near-critical) conditions of the extraction fluid, followed by the extraction step provides similar or even better decontamination results when compared to the prior art process. previous one that requires expansion of the fluid for the precipitation of contaminants and additional subsequent regeneration steps before the extraction step is carried out.

In the present invention, to carry out the fluid regeneration step, said adsorbent medium operates in such supercritical (or quasicritical) conditions of pressure and temperature of the extraction fluid, thus preventing the need for phase changes of the extraction fluid in the extraction process. invention. In this way, there is no need to restore the supercritical conditions of the fluid during the cycle operation itself. Just to start the process, the extraction fluid has to be brought to the supercritical or near-critical state. This leads to significant energy savings and. simplified systems for carrying out the process on an industrial scale, as is evident from the comparison between Fig. 2 and Fig. 3.

Naturally, during the cycle of the invention, some variations in the pressure and temperature of the extraction fluid are allowed as long as the fluid remains in the supercritical (or near-critical) state until the end of the

When the cycle time is over, the process is stopped and the decontaminated batch of cork is removed and replaced by another batch of cork to be treated.

These exchange tasks are carried out close to ambient conditions of pressure temperature.

To start a new cycle, the extraction fluid has to be adjusted just once to the desired supercritical or quasi-critical pressure and temperature conditions and the above-mentioned step a) starts the new cycle. Then, during the cycle itself, as no significant pressure and/or temperature variations will occur, it is easy and cost-effective to keep the extraction fluid in its supercritical or near-critical state.

As for the improvement in terms of cost of the present invention, compared to the conventional process of the prior art, a comparative experimental study was carried out regarding energy consumption and CO2 utilization - The results are shown in the following Table 1.

Item Prior art SFE process SFE process of invention CO2 (kg.kg ^-1 of cork) 40 3./0 5 to 7 E energy (k Wh . k. g ¹ of cork) 2.5 to 3.0 0.6 5 to 0.7 5

Table 1

The savings provided by the present invention compared to the prior art are quite significant.

To preserve the quality of the cork material, an appropriate moisture content in the cork material [usually up to 20% w/w, preferably between 2 and 15% w/w, more preferably between 5 and 10% w/w - In prior art processes, a continuous stream of co-solvent (i.e., water) has. to be fed to mix with the extraction fluid in the supercritical state, because in the expansion step (depressurization) the co-solvent also condenses, thus separating from the extraction fluid. Another advantage of the invention is that it does not require such a continuous stream of co-solvent (i.e. water) to maintain the moisture content of the cork, because the absence of the depressurization step eliminates the problem of co-solvent condensation. This one. In this way, it is much easier to preserve the proper humidity conditions of the cork material.

Preferably, the adsorbent medium of the invention is selected from the group comprising activated carbon, clays, diatomaceous earth, zeolite material, silica gel, resins, and combinations thereof; more preferably, the adsorbent medium is activated carbon.

In fact, it is quite surprising that the process of the invention is capable of effectively decontaminating the cork material using a single fluid regeneration step that is carried out under the supercritical (or near-critical) conditions of the extraction fluid, without the need for additional extraction fluid filtration steps, for several reasons, namely because it is not expected that:

• an adsorbent medium such as activated carbon used in the prior art as an option and complementary to the main usual filtration step (using precipitation by pressure drop) is sufficient to carry out the rluid regeneration alone;

• the adsorbent medium is able to function under such supercritical (or near-critical) conditions of pressure and temperature without losing its adsorption capacity or decreasing the thermodynamic distribution coefficients of the contaminants to be adsorbed, thus further reducing a regeneration action of fluid that was thought to be insufficient if considered in isolation;

• the problem of also removing larger molecules such as long-chain aliphatic alcohols, waxes and fats from the extraction fluid could be overcome without a precipitation step, as it was thought that an adsorbent medium would quickly become saturated or blocked by said larger molecules.

Despite the aforementioned expectations of the expert, the present invention is able to carry out an effective decontamination of the cork material, while allowing considerable savings in the amount of extraction fluid, energy per unit weight of cork material and costs. of maintenance.

In one embodiment of the invention, the circulation of extraction fluid from step a), to extract the contaminating compounds from the cork, and the circulation of fluid containing contaminants from step b), to regenerate the extraction fluid, are carried out at the same isobaric pressure.

In a preferred embodiment, said steps a) and b) are carried out both under the same isobaric and isothermal conditions. In other words, the supercritical or quasi-critical extraction fluid is circulated in both steps a) and b) under the same pressure and temperature conditions.

It was surprisingly verified that the execution of the regeneration of the extraction fluid under the same supercritical (or near-critical) conditions does not penalize the elimination of contaminants because, in fact, the adsorbent medium maintained its high adsorption capacity, and the coefficients were preserved. favorable thermodynamic distribution of contaminants between the adsorbent and the extraction fluid.

The weight ratio of adsorbent medium to cork material that is required for total decontamination of cork depends on the operating conditions of the process and the initial concentration of contaminants in the cork. In the particular case of activated carbon, it was surprisingly verified experimentally that amounts of activated carbon as low as 1.5% by weight of cork material were sufficient to regenerate the extraction fluid, even for initial TCA levels in cork as high as 25 ng.L ^-1 . This result further reinforces the significant savings on an industrial scale provided by the present invention over the prior art. On the other hand, it provides the technical evolution of allowing keeping the adsorbent medium together with the cork bed in the same extraction chamber, without a negative impact on the productivity of the process that would result from sacrificing useful space for the cork material inside the extraction chamber , if larger amounts of adsorbent had to be used in there.

With reference now to the particular embodiment of Fig. 3, in step a) - the extraction fluid, under the desired supercritical or quasicritical conditions, is circulated through the extractor (D) containing the cork bed and solubilizes the cork extractables. In this phase there is a very small continuous pressure drop (from 0.001% to 1% of the operating pressure per meter of cork bed) as the fluid flows through the cork bed; then in step b) - still under supercritical or quasicritical conditions, the extraction fluid circulates through an adsorbent medium (G), preferably an adsorbent bed, more preferably activated carbon, where the fluid undergoes a small continuous pressure drop (from 0.01% to 5% of operating pressure per meter of adsorbent bed). In this step, the adsorbent bed adsorbs extracted contaminants from the extraction fluid, ensuring that clean extraction fluid is recycled to the extractor (D). A small heat exchanger (C3) is used to compensate for heat loss from the equipment to the environment. A fan (B2) is used to recirculate the extraction fluid and to compensate for the aforementioned small pressure drops caused by flow through the cork and adsorbent beds. This cycle is repeated for a predetermined period of time which usually depends on the amount and type of cork material to be decontaminated.

It should be noted that the small pressure drops mentioned naturally result from the physical phenomenon of fluid percolation through the cork material. and through the adsorbent medium. Usually such pressure drops are in the range of 0.001% to 5% of the operating pressure per meter of solid bed. Although these pressure drops have to be compensated every time, the energy involved is proportionally low. Thus, in the context of the invention, when reference is made to isobaric and/or isothermal conditions, it is considered that such unavoidable pressure or temperature variations are insignificant compared to the absolute operating conditions.

Regarding the cycle time, it should be noted that the decontamination of granulated cork can be carried out in significantly less time than larger cork materials, such as, for example, cork stoppers or cork planks/plates. Since the latter materials imply greater thicknesses, the diffusion of solutes from their innermost locations to the outer surface of the material can make the extraction time much longer than that required to decontaminate cork.

grainy.

In this way, the decontamination cycle times are comprised in the range of 10 to 480 minutes, preferably 10 to 240 minutes, more preferably 15 to 100 minutes, most preferably between 20 and 60 minutes.

In one embodiment, the extraction fluid comprises at least

50% by weight CO ₂ .

Preferably, the extraction fluid supply is at least 2 kg.kg ^-1 of cork, preferably between 5 kg.kg ^-1 of cork and 20 kg.kg” ¹ of cork material.

Preferably, the amount of activated carbon used as adsorbent medium is between 1.5% and 25% by weight of cork material, more preferably between 1.5% and 8%, even more Preferred is between 2% and 5%, most preferably 2.5% by weight of cork material. Of course, amounts greater than 25% activated carbon would work, but it is technically and economically advantageous to use as low amounts of activated carbon as possible, as already mentioned.

Preferably, the operating temperature ranges between 20°C and

160 °C, more preferably between °C and 90 °C, even more preferably between 50 °C and 80 °C, most preferably 60 °C.

Preferably, the operating pressure is greater than 4x10® ⁶ Pa, more preferably between 6x10® and 30x10® Pa, more preferably between 7x10® and 15x10 ⁶ Pa, most preferably 10x10 ⁶ Pa.

In a further preferred embodiment, the process of. The invention comprises: a) circulating a mixture of saturated CO2 with water at 10x10® Pa. and 60 °C, through a batch of granulated cork followed by b) circulating the CO2 saturated with water and containing contaminants through a bed of activated carbon under the same pressure and temperature conditions as in step a); followed by repeating step a) with CO2 saturated with water and free of contaminants from step b); and repeat the cycle for 30 minutes, where the mass of activated carbon is 2.5% of the mass of granulated cork, and the mass of granulated cork is 14% of the mass of circulated CO2.

The invention also relates to a system designed to carry out the process of the invention described above.

Fig. 4 schematically shows a preferred embodiment of the system of the invention, a. which should not be considered limiting, since different embodiments can be designed to practice the invention. At. Fig. 4, the arrows schematically illustrate the circulation of the extraction fluid.

system for decontamination of cork material according to the invention comprises an extraction chamber (1); a pumping means (2) disposed inside the. extraction chamber (1) for circulating an extraction fluid; an adsorbent medium support (3); and a support means of cork material (4) arranged inside the extraction chamber (1).

In the preferred embodiment of Fig. 4, also said adsorbent medium support (3) is arranged inside the extraction chamber (1).

In the context of the present invention, the pumping means (2) is any means capable of circulating the extraction fluid through the cork bed and through the adsorbent medium, ensuring the continuity of the cycle of the present invention. It must be able to overcome the small to moderate pressure drops that may occur during the process, which, however, are not sufficient to remove the fluid from its supercritical or near-critical state. Preferably, the pumping means (2) is a fan or a centrifugal or positive displacement pump.

It has surprisingly been found that in operation a stabilization of the pressure and temperature conditions inside the extraction chamber (1) is achieved by arranging said pumping means (2) inside the extraction chamber (1). Even better results are achieved by also arranging the adsorbent medium support (3) inside the extraction chamber (1). These arrangements provide simpler and more compact extraction systems compared to the prior art, allowing significant savings in equipment costs of such compact embodiments and in energy and maintenance costs of the. your operation.

The compact embodiment in which both the adsorbent medium support (3) and the pumping medium (2) are arranged inside the extraction chamber (1) revealed a better performance of the process to operate under isobaric and isothermal conditions for the fluid of extraction in the extraction cycle. This increased stability has resulted in optimized energy costs.

A possible design of the last compact embodiment is the arrangement of three compartments within the extraction chamber, where the compartments are interconnected for fluid communication, but separated for solids, so that the extraction fluid can flow from one compartment to another. another by action of the pumping medium. A first compartment contains the pumping medium, a second compartment contains the adsorbent medium support, and a third compartment contains the cork material support medium.

Said three compartments containing the pumping medium (2), the adsorbent medium support (3), and the cork material support means (4) can be arranged in series in any order. Preferably, they are arranged in series in the following order: pumping medium compartment, adsorbent medium support compartment and cork material support medium compartment.

In operation, when the supercritical (or near-critical) decontamination cycle ends, the extraction chamber is depressurized to remove the decontaminated cork and exchanged for a new bed of cork to be extracted, and the extraction fluid returns to a storage vessel . The extraction fluid can be stored as such or is passed first through an adsorbent bed (containing activated carbon or other adsorbent) under low pressure in order to remove trace amounts of some remaining volatile compounds, and thus the extraction fluid extraction can be stored in high purity until a new decontamination cycle is established.

EXAMPLES A number of experiments were carried out based on the decontamination process of the invention and using a prototype of the described deprecated system of the invention.

Since it is known from the prior art that supercritical fluid extraction can decontaminate cork material within a wide range of pressures and temperatures (supercritical and near-critical) using different extraction fluids, the aim of these experiments was to demonstrate that it is sufficient using a single extraction fluid regeneration step, carried out in the supercritical or near-critical conditions of the extraction fluid, and using an adsorbent medium. As the extraction step and the fluid regeneration step are carried out under similar Pressure and Temperature (P-T) conditions, energy consumption and the required amount of extraction fluid are considerably reduced, thus greatly improving operating costs (opex ) relative to prior art processes, as demonstrated by the results in Table 1 above.

Once the.

The wine industry requires corks with amounts of 2,4,6-trichloroanisole (TCA) below 0.5 ng.L ^-1 , TCA was the reference contaminant measured in these experiments. Thus, after completion of the treatment cycle, a. extraction chamber was depressurized, the cork material was removed and submitted to TCA analysis by Microextraction in solid phase and Gas Chromatography with Mass Spectrometry (SPME-GC-MS) according to International Standard ISO 20752.

Tables 2 and 3 show the TCA levels, respectively in granulated cork and natural cork stoppers, before and after decontamination by the SFE process of the invention.

Table 2 below shows different operating conditions used in fifteen experiments with granulated cork and activated carbon as adsorbent medium. The extraction fluid used was COz, either alone or in combination with water added until saturation. The extraction results in both cases were similar, as all assays showed less than 0.5 ng.L ^-1 of TCA after decontamination.

Rehearsal Cork granulometry (mm) Cork mass (g) CO ₂ Used (g) Activated carbon (% by weight of cork) Cycle time (min) Temp. ("O Pressure (Pa) [TCA] Before cycle (ng.L ¹ ) [TCA] After 0 cycle (ng.L·· ¹ ) - 200 14 0 0 50.0 60 60 10.5xl0 ⁶ 11, 8 <0.5 two 1-2 200 1400 25.0 60 60 10xl0 ^b 23, 6 <0.5 3 1-2 201 142 5 2 5.0 30 60 10xl0 ^b 12.4 <0.5 4 1-2 2 00 1415 2 5.0 30 7 0 9x10 ^b 9.0 <0.5 5 1 201 142 5 20.0 30 60 10x10 ⁶ 12.1 <0.5 6 0.5-1 8 90 62 30 12.0 60 60 ^10xl0b 13, 5 <0.5 7 1-2 2 00 .1.4 00 2.5 2 5 60 ^10xl0b 10, 7 <0.5 8 1-2 2 00 1400 2.5 20 60 10x10 ⁶ 11, 4 <0.5 9 200 14 0 0 2.5 17 60 10x10 ⁶ 11, 8 <0.5 10 1-2 8 90 62 30 25.0 30 7 0 9xl0 ^b 22.9 <0.5

11 1-2 200 1400 2.5 30 7 0 9xl0 ⁶ 18, 1 <0.5 12 1-2 200 14 7 0 2.5 30 60 10x10 ⁶ 11, 1 <0.5 1 J 1-2 200 1390 2.5 20 60 10xl0 ⁶ 15.2 < 0 _f 5 14 3-7 200 14 7 0 60 50 9x10 ⁶ 10, 5 <0.5 15 3 - 7 200 14 7 0 5 90 4 0 7.5x10 ⁶ 6, 1 <0.5

Table 2

Six similar lots of fourteen natural cork stoppers (about 44 g each lot) were subjected to the decontamination process of the invention using CO2 as extraction fluid (about 305 g), either pure or in combination with water added until saturation, for 480 min at 10x1O ⁶ Pa and 60 °C, using 1.5%, 4.0% and 8.0% activated carbon as adsorbent medium. Before the decontamination cycle, all cork stoppers were evaluated for their level of contamination through individual analysis by SPME-GC-MS in accordance with a. International Standard ISO 20752. After completion of the decontamination cycle, the extraction chamber was depressurized, the corks were removed and subjected to individual TCA analysis by SPME-GC-MS in accordance with International Standard ISO 20752. extraction were all similar and independent of water content and amount of adsorbent, since all assays showed less than 0.5 ng.L ^-1 of TCA after decontamination.

Table 3 presents the results achieved for the experiment using fourteen cork stoppers (total mass of 43.6 g), 305.7 g of pure CO2, and 1.5% of activated carbon, having established the remaining operating conditions .

:to the)

RoXh.es de [TCA] Before the | [TCA] After 0 | cork cycle (ng.L ^-1 ) 23.0 <0.5 two 15.7 <0.5

(continuation)

corks [TCA] Before the cycle (ng.L” ¹ ) [TCA] After cycle (ng.L ^-1 ) 3 15.7 <0.5 4 9.5 <0.5 β _Λ 5 <0.5 6 5, 4 <0.5 ! 5.0 <0.5 8 4.9 <0.5 9 4.7 <0.5 10 3, 9 <0.5 11 3, 7 0 f ' / 3, 5 <0.5 13 3, 5 0 f 14 3.0 <0.5

Table 3

The description presented herein should be interpreted as non-limiting of its scope which is defined only by the independent claim. The dependent claims define particular embodiments of the invention.

Claims (10)

1. Process for extracting 2,4,6-trichloroanisole (TCA) from cork material characterized by comprising the steps of: a) Circulate CO2 in a supercritical or near-critical state as extraction fluid through a batch of cork material in order to extract TCA. cork by solubilizing it in the extraction fluid; followed by b) circulate the CO2 containing TCA from step a) under supercritical or quasi-critical conditions of pressure and temperature through a bed of activated carbon, in order to eliminate the TCA from the extraction fluid by adsorption; followed by c) repeating step a) with the regenerated extraction fluid obtained in step b); It is d) repeating steps b) and c) for a predetermined period of time; in which steps a) and b) comprise circulating the extraction fluid at the same pressure and at the same temperature in both steps a) and b), the pressure being in the range of 6x10® to 30x10® Pa and the temperature in the range of 2 0 ⁰ C to 160 ⁰ C. 2. Process according to claim 1, characterized in that step b) comprises circulating the extraction fluid containing contaminants through an amount of activated carbon in the range of 1.5% to 8% by weight of the cork material, of a preferably 2% to 5%, more preferably 2.5%. Process according to claim 1, characterized in that the steps a) and b) comprise circulating water mixed with CO2, the water in the range of 0.05% w/w until saturation. Process according to any one of the preceding claims, characterized in that steps a) and b) comprise circulating CO2 at a pressure in the range of 7x10 ^s to 15x10 ⁶ Pa, more preferably 10x10 ⁶ Process according to claim 4, characterized in that the steps a) and b) comprise circulating CO2 at a temperature in the range of 30°C to 90°C, more preferably 50°C to 80°C, most preferably 60°C. 6. Process according to a. claim 1, characterized in that it comprises: a) circulating a mixture of CO2 saturated with water, at 10x10® Pa and 60 °C _f , through a batch of granulated cork followed by b) circulating the CO2 saturated with water and containing contaminants through a activated carbon bed under the same pressure and temperature conditions as in step a); followed by repeating step a) with CO2 saturated with water and free of contaminants from step b); and repeat the cycle for 30 minutes, where the mass of activated carbon is 2.5% of the mass of granulated cork, and the mass of granulated cork is 14% of the mass of circulated CO2. System for carrying out the process as claimed in any one of claims 1 to 6, comprising: • an extraction chamber (1); ® a pumping means (2) for circulating an extraction fluid; • an adsorbent medium support (3) for supporting an adsorbent medium; and • a support means of cork material (4) arranged inside the extraction chamber (1), characterized in that said pumping means (2) is arranged inside the extraction chamber (1). 8. System according to claim 7, characterized in that said adsorbent medium support (3) is arranged inside the extraction chamber (1). 9. System according to claim 7, characterized in that it comprises three compartments within the extraction chamber (1), said compartments interconnected for fluid circulation, in which each compartment contains, respectively, the pumping means (2), the adsorbent medium support (3), and the cork material support medium (4). System according to claim 9, characterized in that said three compartments are arranged in series in any order. 11. System according to claim 8, characterized in that said compartments are arranged in the order of pumping medium compartment (2), adsorbent medium support compartment (3) and cork material support medium compartment (4 ).