WO2020201411A1

WO2020201411A1 - Sugar processing method

Info

Publication number: WO2020201411A1
Application number: PCT/EP2020/059379
Authority: WO
Inventors: Damien BRICHANT; Antoine CHARBONNEAU
Original assignee: Novasep Process
Priority date: 2019-04-05
Filing date: 2020-04-02
Publication date: 2020-10-08
Also published as: FR3094724B1; FR3094724A1; CO2021010990A2; BR102020006522A2

Abstract

The invention relates to a sugar processing method comprising, in a series: a first frontal filtration of a sugar juice in order to obtain a first filtrate; a second frontal filtration of the first filtrate in order to obtain a second filtrate; and bringing the second filtrate into contact with a cation-exchange chromatography resin so as to load the resin with divalent cations and to collect a sweetened sugar juice, the resin being arranged in the form of a bed that has a height h between 0.75 and 3 metres. The invention also relates to a sugar processing device.

Description

Sugar processing process

Field of the invention

The present invention relates to a sugar treatment process comprising a step of sweetening a sweet juice on an ion exchange chromatography resin. The present invention also relates to a sugar treatment device which makes it possible in particular to sweeten a sweet juice.

Technical background

The production of refined sugar from cane sugar comprises a certain number of treatments carried out in the sugar refinery followed by a certain number of additional treatments carried out in the refinery.

In the sugar industry, the main steps are the extraction of the sugar by grinding, that is to say the pressing of the cane or by diffusion to obtain a raw sweet juice, the clarification of this juice by adding lime in order to precipitate a certain number of impurities as well as by addition of carbon dioxide (carbonation) or sulfur dioxide (sulfitation) in order to precipitate excess lime, filtration or decantation of the treated juice, the concentration of the remaining juice and finally crystallization and the turbining of the sugar, which leads to obtaining brown sugar on the one hand and molasses on the other.

In the refinery, the main operations to which brown sugar is subjected are refining (washing the crystals with a saturated aqueous solution of sugar then turbining) to remove the impurities located on the surface of the crystals, re-dissolving the resulting sugar, clarification , discoloration and crystallization.

However, excess precipitated lime, especially in the form of calcium carbonate (CaCC) or calcium sulphate (CaSC), can cause problems by accumulating and precipitating in equipment as well as in pipes. over time. Specifically, mineral deposits can be formed in the evaporator used for the concentration of sweet juice, increasingly reducing heat exchange and thus leading to a gradual decrease in its effectiveness. Thus, maintaining the same evaporation rate over time requires an increase in the consumption of vapors and / or an increase in the heating surface. In addition, after a certain level of decrease in performance, the evaporator must be stopped to clean the deposits formed. This cleaning process, which includes a succession of chemical and mechanical cleanings (manual operation), requires the systematic opening of the devices and is considered dangerous, given that the temperatures around the evaporator are high, but also that the use of concentrated chemicals is necessary. In addition, stopping and restarting an evaporator requires additional consumption of coolant in one case and of steam in the other, due to the inertia of the device.

A few improved cleaning solutions exist, however they require a large investment as well as high operating costs.

The sweetening of the sweet juice is a method which allows to decrease the quantity of cationic counterions causing mineral deposits. The most common technique for sweetening the sweet juice is based on the use of a cation exchange chromatography resin (before the evaporation step), for example in the Na ⁺ or K + form so as to exchange the divalent cations ( Ca ²⁺ , Mg ²⁺ ) present in the juice sweetened with monovalent cations (Na ⁺ or K ⁺ ) and avoid the problems mentioned above. This technique is often combined with membrane filtration (tangential filtration) carried out before the ion exchange chromatography step, in order to remove suspended matter which is present in the clarified juice and which can very quickly degrade the performance and capacity of the installation used for ion exchange chromatography.

However, the use of filtration membranes makes the implementation of this technique very expensive.

The article by V. Kochergin and JF Alvarez (lon-exchange softening of clarified juice-results of pilot trials) in “Agribusiness Intelligence Journal- Informa” in 2017 describes trials carried out for the sweetening of sugar cane juice, in using filtration through a screen filter, followed by cation exchange on a shallow-bed resin.

Document FR 2 838 751 describes a process for manufacturing refined sugar from sweet juice such as raw sugar cane or sugar beet juice, containing sugars and impurities, characterized in that it comprises (among others) tangential filtration of the sweet juice to obtain a retentate and a filtrate, and softening of the filtrate to obtain a soft filtrate. Tangential filtration is preferably membrane filtration (ultrafiltration, nanofiltration, microfiltration) and the softening is implemented by means of a cation exchange resin.

Document CN 103725802 describes a process for refining sugar. This process comprises (among others) a pretreatment step which can be filtration through a screen filter or a bag filter, a membrane microfiltration step, an anion exchange step for the decoloration of the juice and a step of exchange of cations for desalination of juice.

Document FR 2 732 358 describes a process for treating a sugar solution obtained from beet with a cationic ion exchange resin to soften the sugar solution, followed by regeneration of the cationic resin. Filtration can precede the ion exchange step.

Document US Pat. No. 6,479,636 describes a method for extracting and purifying recombinant proteins from transgenic sugar cane. This method includes several stages of filtration through a screen filter and an ion exchange stage on an anionic resin.

Document WO 2005/031006 describes a process in which the raw sugarcane juice is first refined in several stages, then bioenzymatically converted into invert syrup or into a concentrated solution of refined glucose-fructose. The refining steps preferably comprise a first filtration (particle filtration or microfiltration) followed by a second filtration (microfiltration or ultrafiltration) then at least one passage through a column comprising an anion exchange resin.

Document CN 102659855 relates to a sugar production process comprising (among others) a filtration step on a filter press, a pretreatment step comprising a filtration, a membrane filtration step, and an ion exchange step for remove color from flavonoids.

There is therefore a need to provide an improved sugar treatment process, comprising a sweet juice sweetening step, making it possible to avoid the risks of plant malfunctioning, the risks associated with cleaning the facilities, but also to reduce costs. economic and energy related to the different stages of the process.

Summary of the invention The invention relates firstly to a process for treating sugar, comprising successively:

- a first frontal filtration of a sweet juice to obtain a first filtrate;

- a second frontal filtration of the first filtrate to obtain a second filtrate; and

- Contacting the second filtrate with a cation exchange chromatography resin so as to charge the resin with divalent cations and to collect a sweetened sweet juice, the resin being arranged in the form of a bed having a height h of 0 , 75 to 3 meters.

According to some embodiments, the divalent cations comprise, and preferably consist essentially of Ca ²⁺ cations and / or Mg ²⁺ cations.

According to some embodiments, the sweet juice has a solid particle concentration of 20 to 500 mg / kg, and / or a magnesium ion concentration of 100 to 500 mg / L, and / or a calcium ion concentration of 100 to 600 mg / L.

According to some embodiments, the sweet juice has a sugar content of 10 to 20 degrees Brix, and / or a turbidity of 100 to 500 NTU.

In some embodiments, the sweetened sweet juice collected after the step of contacting the second filtrate with the resin has a volume of 15 to 80 BV.

According to some embodiments, the first filtration allows a retention of 10 to 60% by mass of solid particles relative to the amount of solid particles present in the sweet juice, and / or the first filtration and the second filtration allow a retention of 30 to 70% by mass of solid particles relative to the amount of solid particles present in the sweet juice, and / or the first filtration, the second filtration and the contacting of the second filtrate with the resin allow a retention of 50 to 90% by mass of solid particles relative to the amount of solid particles present in the sweet juice.

According to some embodiments, the process is a batch process or a continuous process.

According to certain embodiments, the method comprises steps for regenerating the resin loaded with divalent cations, these steps comprising: - bringing the loaded resin into contact with a regeneration solution;

- the collection of a regeneration effluent.

According to certain embodiments, the regeneration solution is obtained from molasses formed during a sugar crystallization step, or the regeneration solution is obtained in all or part of the sweetened juice, with or without sodium hydroxide added or of potassium hydroxide, or the regeneration solution is a regeneration brine solution comprising a chloride, or potassium or sodium salt, or the regeneration solution is obtained from a stillage from the distillation of molasses; or the regeneration solution is obtained from a raffinate resulting from a treatment by chromatography of molasses.

In some embodiments, contacting the loaded resin with a regeneration solution includes the use of different regeneration solutions alternating between two production cycles.

According to some embodiments, the regeneration effluent is used to perform a sweet juice clarification step, in particular a liming step, the clarification step being performed before the first filtration; or the regeneration effluent is used to perform one or more crystallization steps, the crystallization step (s) being performed after contacting the second filtrate with the resin.

According to some embodiments, the method also comprises a step of washing the resin loaded with divalent cations, or the regenerated resin, with a washing solution, the washing solution having a direction in the resin bed reverse to a direction. of the second filtrate in the resin bed during the step of bringing the second filtrate into contact with the resin.

In some embodiments, the wash solution is made from the sweetened sweet juice or the sweet juice, or the wash solution is water.

According to some embodiments, at the end of the washing step, a washing effluent is collected, the washing effluent being returned to a sweet juice clarification step, the clarification step being carried out before the first filtration.

According to some embodiments, the step of bringing the second filtrate into contact with the resin is carried out at a temperature equal to or greater than 75 ° C.

The invention also relates to a sugar processing device, comprising: - a supply line for a sweet juice;

- a first front filtration unit supplied by the sweet juice supply line;

- a first filtrate collection line at the outlet of the first front filtration unit;

- a second front filtration unit supplied by the first filtrate collection line;

- a second filtrate collection line at the outlet of the second front filtration unit;

- an ion exchange chromatography unit comprising a cationic resin supplied by the second filtrate collection line, the resin having the form of a bed having a height h of from 0.75 to 3 meters; and

- a collection line for sweetened sweet juice at the outlet of the ion exchange chromatography unit.

According to some embodiments, the first filtration unit comprises one or more screen filters, each filter having pores having a diameter of 50 to 200 µm, and preferably 80 to 120 µm.

In some embodiments, the first filtration unit includes a cleaning unit for at least one of the screen filters.

According to some embodiments, the second filtration unit comprises at least one filter basket having pores having a diameter of 20 to 100 µm, and preferably 40 to 60 µm.

According to some embodiments, the ion exchange chromatography unit comprises at least one column, preferably at least 5 columns, more preferably at least 10 columns, and more preferably at least 15 columns.

In some embodiments, the resin bed has a diameter of 0.25 to 6 m, and preferably 0.25 to 5 m.

The present invention makes it possible to meet the need expressed above. More particularly, it provides an improved sugar treatment process, comprising a sweet juice sweetening step, making it possible to avoid the risks of plant malfunction, the risks associated with cleaning the facilities, but also to reduce economic and energy costs. linked to the different stages of the process.

This is accomplished through a sugar treatment process comprising the successive steps of a first front filtration, a second front filtration and an ion exchange chromatography step. on a cationic resin. The two successive front filtration stages protect the ion exchange chromatography resin and the ion exchange chromatography unit from performance and capacity degradation problems, by separating solid particles that are in suspension in sweet juice and which may accumulate in the ion exchange chromatography unit. This enables improved efficiency of the softening step without damaging the ion exchange chromatography unit. The two filtration steps therefore make it possible to smooth out the variations of the solid particles present in the product and to limit the number of fibrous solid particles accumulated in the ion exchange chromatography unit. Thus, advantageously, at the end of the second filtration, from 30 to 70% by mass of particles present in the sweet juice are retained by the filters, and at the end of the ion exchange chromatography step, of 50 to 90% by mass of particles present in the sweet juice are retained by the filters and the resin. Thus, this process not only makes it possible to protect the ion exchange chromatography resin and the ion exchange chromatography unit but also to avoid deposits formed in the installations, in particular in the evaporator during the concentration. juice, and limit all the inconveniences associated with cleaning and recurring shutdown of these installations.

In addition, the first frontal filtration and the second frontal filtration are carried out, preferably, in filtration units devoid of membranes of ceramic or other mineral type (stainless steel for example), which makes it possible to reduce the cost of these steps of the process. .

Advantageously and surprisingly, the combination of frontal filtration with a specific pore opening (pore size) makes it possible to maintain a good height of the resin bed. In fact, in the usual way, the presence of solid fibrous particles in the sweet juice to be purified often leads, due to the risk associated with the blocking of the column, to a need to reduce the height of the resin bed and thus to distribute the bed of the resin on several columns. On the contrary, the present invention makes it possible, despite a micrometric-sized pore opening, to maintain a good resin bed height without having to distribute the resin on other columns of low bed height.

Again advantageously, washing the resin loaded with divalent cations (Ca ²⁺ and Mg ²⁺ ) with a washing solution, the washing solution having a direction in the resin bed opposite to the direction of the second filtrate in the bed of resin (during the production of sweetened sweet juice), this washing is also called backwashing, allows solid particles to be evacuated retained in the ion exchange chromatography unit. More precisely, these retained particles preferentially accumulate near the inlet (for example towards the top) of the ion exchange chromatography unit. During the washing step, and thanks to the direction of the washing solution (e.g. from the bottom to the top of the unit) and the flow rate of the washing solution, an expansion of the resin bed in the unit ion exchange chromatography can be obtained. The solid particles present in the unit generally have a lower density than the density of the resin, and they can be discharged from the unit without causing the resin particles to exit. Thus, the resin now essentially free of solid particles can be regenerated and reused.

Brief description of the figures

FIG. 1 schematically represents a mesh grid comprising a first series of threads (A), a second series of threads (B), and a third series of threads (C).

FIG. 2 schematically represents the different steps of the method according to the invention, in certain embodiments.

detailed description

The invention is now described in more detail and in a non-limiting manner in the description which follows.

The invention relates to a device and a method for the treatment of sugar, which makes it possible to remove solid particles in suspension in a sweet juice as well as divalent cations such as calcium ions Ca ²⁺ and / or the magnesium Mg ²⁺ ions present in the sweet juice. More particularly, this process aims to purify and in particular to soften a sweet juice.

Sweet juice

By “sweet juice” is meant a liquid stream containing sugars and impurities, in particular solid particles in suspension and Ca ²⁺ and / or Mg ²⁺ cations. Preferably, the solid particles in suspension comprise bagasse and fine bagasse fractions called "bagacillos". By "bagasse" is meant solid fibrous particles in suspension originating from the extraction of the sweet juice and by "bagacillos" is meant fine solid and fibrous particles in suspension originating from the extraction of the sweet juice. The sweet juice is advantageously made from sugar cane. It may have undergone one or more pretreatment steps called clarification, such as centrifugation, filtration, carbonation, flocculation, decantation, sulphitation and / or liming steps.

The term "softening" means the reduction in the hardness of the sweet juice due to the presence of divalent ions, in particular Ca ²⁺ and / or Mg ²⁺ . Thus, during sweetening of sweet juice, Ca ²⁺ and / or Mg ²⁺ ions are eliminated and replaced by monovalent cations such as sodium (Na ⁺ ) or potassium (K ⁺ ) ions.

The Ca ²⁺ and / or Mg ²⁺ ions can be present naturally in the sweet juice and / or come from one or more pretreatment steps as mentioned above.

Advantageously, the sweet juice to which the process of the invention is applied comprises Ca ²⁺ ions at a concentration of 100 to 800 mg / L, and preferably of 100 to 600 mg / L. For example, this concentration of Ca ²⁺ ions can be from 100 to 150 mg / L; or from 150 to 200 mg / L; or from 200 to 250 mg / L; or from 250 to 300 mg / L; or from 300 to 350 mg / L; or from 350 to 400 mg / L; or from 400 to 450 mg / L; or from 450 to 500 mg / L; or from 500 to 550 mg / L; or from 550 to 600 mg / L; or from 600 to 650 mg / L; or from 650 to 700 mg / L; or from 700 to 750 mg / L; or 750 to 800 mg / L. The concentration of Ca ²⁺ ions can be measured using the ICUMSA GS7-19 standard.

Advantageously, the sweet juice to which the process of the invention is applied comprises Mg ²⁺ ions at a concentration of 100 to 800 mg / L, and preferably of 100 to 500 mg / L. For example, this concentration of Mg ²⁺ ions can be 100 to 150 mg / L; or from 150 to 200 mg / L; or from 200 to 250 mg / L; or from 250 to 300 mg / L; or from 300 to 350 mg / L; or from 350 to 400 mg / L; or from 400 to 450 mg / L; or from 450 to 500 mg / L; or from 500 to 550 mg / L; or from 550 to 600 mg / L; or from 600 to 650 mg / L; or from 650 to 700 mg / L; or from 700 to 750 mg / L; or 750 to 800 mg / L. The concentration of Mg ²⁺ ions can be measured using the ICUMSA GS7-19 standard.

According to some embodiments, the sweet juice comprises divalent Ca ²⁺ cations.

According to other embodiments, the sweet juice comprises divalent Mg ²⁺ cations.

Alternatively and advantageously, the sweet juice comprises divalent Ca ²⁺ and Mg ²⁺ cations.

Advantageously, the sweet juice to which the process of the invention is applied comprises solid particles at a concentration of 10 to 800 mg / kg, and preferably 20 to 500 mg / kg. For example, this concentration of solid particles can be 10 to 50 mg / kg; or from 50 to 100 mg / kg; or from 100 to 150 mg / kg; or from 150 to 200 mg / kg; or from 200 to 250 mg / kg; or from 250 to 300 mg / kg; or from 300 to 350 mg / kg; or from 350 to 400 mg / kg; or from 400 to 450 mg / kg; or from 450 to 500 mg / kg; or from 500 to 550 mg / kg; or from 550 to 600 mg / kg; or from 600 to 650 mg / kg; or from 650 to 700 mg / kg; or from 700 to 750 mg / kg; or 750 to 800 mg / kg. The concentration of solid particles can be measured using the NF T90-105 standard and substituting the 0.45 μm filter as recommended in the standard with an 8 μm filter.

The sweet juice to which the process of the invention is applied can also have a sugar content of 10 to 30 degrees Brix, and preferably 10 to 20 degrees Brix. Thus, the sweet juice to which the process of the invention is applied may have a sugar content of 10 to 12; or from 12 to 14; or from 14 to 16; or from 16 to 18; or from 18 to 20; or from 20 to 22; or from 22 to 24; or from 24 to 26; or from 26 to 28; or 28 to 30 degrees Brix. Brix degrees can be measured using the ICUMSA GS7-31 standard.

In addition, the sweet juice to which the process of the invention is applied may have a turbidity of 100 to 800 NTU, and preferably 100 to 500 NTU (NTU = Nephelometric Turbidity Unit). By "turbidity" is meant the content of light materials suspended in a liquid. It is a quantity measuring the more or less cloudy nature of the liquid. The turbidity of sweet juice can be measured using the ICUMSA GS7-21 standard. Thus, the turbidity of the sweet juice to which the process of the invention is applied can be from 100 to 150

NTU; or from 150 to 200 NTU; or from 200 to 250 NTU; or from 250 to 300 NTU; or from 300 to 350 NTU; or from 350 to 400 NTU; or from 400 to 450 NTU; or from

450 to 500 NTU; or from 500 to 550 NTU; or from 550 to 600 NTU; or from 600 to

650 NTU; or from 650 to 700 NTU; or from 700 to 750 NTU; or from 750 to 800 NTU.

Sugar processing device

The device according to the invention comprises first of all a supply line for a sweet juice which is linked on the one hand to a first front filtration unit. On the other hand, this supply line can be linked to (from) a clarification unit, or a carbonation unit, or a settling unit, or a flocculation unit, or a centrifugation unit, or a filtration, or a reservoir comprising the sweet juice to be purified. So the supply line allows to transfer (and thus feed) the sweet juice to be purified in the first front filtration unit.

By "front filtration" is meant filtration which takes place essentially perpendicular to the surface of the filter. Thus, any material retained by the filter accumulates on its surface. On the contrary, "tangential filtration" consists in passing the fluid tangentially to the surface of the filter.

Furthermore, it is known to those skilled in the art that the front filtration is carried out in units having a pore opening (pore size) greater than 1 µm.

The first front-end filtration unit may include one or more screen filters, that is, filters comprising a mesh screen serving to sort and retain solid particles. The mesh grid may be made of wires which are preferably welded together.

According to some embodiments, the mesh grid can include a first series of wires which are parallel to each other.

According to other embodiments, the mesh grid can include the first series of threads and a second series of threads which are parallel to each other and perpendicular to the threads of the first series.

According to other embodiments, and with reference to Figure 1, the mesh grid may include the first series of wires (A), the second series of wires (B), and a third series of wires (C) which are parallel to each other and having an angle greater than 0 ° and less than 90 ° relative to the son of the first series (A). This angle can for example be from 0 to 10 °; or from 10 to 20 °; or from 20 to 30 °; or from 30 to 40 °; or from 40 to 50 °; or from 50 to 60 °; or from 60 to 70 °; or from 70 to 80 °; or from 80 to 90 °. Preferably this angle is 30-60 °, and more preferably this angle is about 45 °.

This preferred and particular mesh helps prevent solid fibrous particles (bagasse) from becoming entangled in the mesh grid in a way that is difficult to clean.

Preferably, the first front filter unit comprises at least 5 screen filters, preferably at least 10 screen filters, preferably at least 15 screen filters, and more preferably at least 20 screen filters. Thus, the first front filtration unit can for example comprise from 1 to 5 filters; or from 5 to 10 filters; or from 10 to 15 filters; or from 15 to 20 filters; or from 20 to 25 filters; or from 25 to 30 filters; or more than 30 filters. Preferably, these filters are arranged in parallel. More preferably, these filters are arranged on a generally cylindrical surface in the first filtration unit.

Each filter can have a filtration area of 1 to 5 m ² , and preferably of 1, 5 to 3 m ² . Thus, the total filtration surface of the first front filtration unit can be from 1 to 150 m ² , and preferably from 15 to 50 m ² .

In addition, each filter (or more particularly the filtration surface of each filter) has pores (opening of the mesh grid) allowing the retention of solid particles on one side and the passage of sweet juice on the other side ( first filtrate). When the pores do not have a circular opening, the term "diameter" of the pores is understood to mean the maximum distance between two points lying in a plane parallel to the opening. For example, for pores having a rectangular or square opening, the diameter refers to the diagonal of each opening. The same is true for pores of a grid comprising a perpendicular mesh combined with a diagonal mesh, as described above.

The pores of the filters of the first filtration unit advantageously have a diameter greater than the pores of the filters of the second filtration unit.

Thus, the pores of each filter of the first filtration unit can have a diameter of 50 to 80 µm; or from 80 to 100 µm; or from 100 to 120 µm; or from 120 to 140 µm; or from 140 to 160 µm; or from 160 to 180 µm; or from 180 to 200 µm. A pore diameter of about 100 µm is particularly suitable.

According to some embodiments, the filters included in the first filtration unit all have pores of the same diameter.

According to other embodiments, the filters included in the first filtration unit have pores having a different diameter from each other.

Preferably, the first filtration unit is devoid of membrane filters (membrane filters are usually used to perform cross-flow filtration).

The first filtration unit may include a cleaning unit for at least one of the filters. This cleaning unit thus makes it possible to clean at least one filter when the remaining filters continue to be operational. More particularly, the pressure is measured for each of the filters throughout the filtration. When the pressure of a filter reaches a limit (clogged filter), a rotary valve allows the direction of the flow of sweet juice from the clogged filter to a clean filter. The clogged filter can then be cleaned while the filtration continues. The cleaning of the filter can for example be carried out with a cleaning solution which has a direction opposite to the direction of the flow of the sweet juice to be purified. This cleaning solution can be hot water and / or an aqueous solution comprising sodium hydroxide (3-5% by mass).

According to some embodiments, the first filtration unit allows the simultaneous use of at least two filters for the filtration of the sweet juice.

In some embodiments, the first filtration unit allows simultaneous cleaning of at least two filters.

According to some embodiments, the first sugar juice filtration unit allows the simultaneous use of at least two filters for filtration and at the same time the simultaneous cleaning of at least two filters and then it allows to alternate so to use the filters previously cleaned for the filtration of the sweet juice and at the same time the cleaning of the filters previously used for the filtration.

According to certain embodiments, the flow of the sweet juice per filter can be from 50 to 150 m ³ / h, and preferably from 70 to 1 10 m ³ / h.

The device of the invention also comprises a collection line which allows the collection of the first filtrate obtained at the outlet of the first filtration unit. The first filtrate collection line supplies a second front filtration unit with the first filtrate.

The second front filtration unit may include at least one filter (enclosure) consisting of filter baskets or sieves. According to some embodiments, the second front filtration unit can include at least two filters, and preferably at least four filters.

Each filter basket included in the filter (enclosure) may have pores (opening of the mesh screen) allowing the retention of solid particles on one side and the passage of sweet juice on the other side (second filtrate).

Thus, the pores of each filter basket of the second filter unit can have a diameter of 20 to 30 µm; or from 30 to 40 µm; or from 40 to 50 µm; or from 50 to 60 µm; or from 60 to 80 µm; or from 80 to 100 µm. A pore diameter of about 50 µm is particularly suitable.

According to some embodiments, the filter baskets included in the second filtration unit all have pores of the same diameter.

According to other embodiments, the filter baskets included in the second filter unit have pores having a different diameter from each other. Preferably, the second filtration unit is devoid of membrane filters (membrane filters usually being used to effect cross-flow filtration).

The device of the invention also comprises a collection line which allows the collection of the second filtrate obtained at the outlet of the second filtration unit. The second filtrate collection line feeds an ion exchange chromatography unit with the second filtrate.

The ion exchange chromatography unit comprises a cation exchange chromatography resin. Preferably, it is a strong cationic exchange resin, in the form of Na ⁺ and / or K ⁺ . The resin is in the form of a compact bed in the ion exchange chromatography unit with a bed height greater than that defined as "shallow bed". In fact, the bed heights are of the order of 0.5 m in a “shallow bed” and the product is distributed through the resin by means of a very complex distributor called “fractal”. The columns of the invention preferably do not include a fluid distributor at the top of the column, at best the principle of distribution of the sweet juice of the invention is based on a simple weir placed at the top of the column. By “weir” is meant a structure which comprises a single inlet and a single outlet for the fluid (here the second filtrate) so as to bring the fluid into the chromatographic column. Thus, the columns of the invention preferably do not include a fluid distributor comprising a plurality of orifices (or outlets) for distributing the fluid in the column.

The resin bed has a height of 0.75 to 3 m, preferably 1 to 3 m and more preferably 1 to 2 m. For example, the resin bed can have a height of 0.75 to 1 m; or from 1 to 1.5 m; or from 1.5 to 2 m; or from 2 to 2.5 m; or 2.5 to 3 m.

The resin bed can also have a diameter of 0.25 to 6 m, preferably 0.25 to 5 m, and more preferably 0.25 to 4.5 m. For example, the resin bed can have a diameter of 0.25 to 0.5 m; or from 0.5 to 1 m; or from 1 to 1.5 m; or from 1.5 to 2 m; or from 2 to 2.5 m; or from 2.5 to 3 m; or from 3 to 3.5 m; or from 3.5 to 4 m; or from 4 to 4.5 m; or 4.5 to 5 m; or from 5 to 5.5 m; or from 5.5 to 6 m. In the case where the resin bed does not have a cylindrical shape with a circular section, the diameter means the maximum dimension of the resin bed in a section perpendicular to its main axis (flow axis of the flows). For example, for a rectangular or square section, the diameter refers to the diagonal. Alternatively, the resin bed can have a frustoconical shape. By “frustoconical” is meant a resin bed having the shape of a truncated cone, the upper part of which has been truncated by a plane. In this case, the diameter is understood as the diameter of the large base of the resin bed.

The ion exchange chromatography unit may comprise at least one column, preferably at least 5 columns, more preferably at least 10 columns, and more preferably at least 15 columns. Thus, in the case where several columns are used, each column comprises a bed of resin.

The resin bed volume per column can be 15 to 40 m ³ , and preferably 20 to 35 m ³ .

The total resin bed volume (i.e., the resin bed volume included in all columns of the ion exchange chromatography unit) can be 15 to 500 m ³ , and preferably from 15 to 450 m ³ .

Each column can have a height of 2 to 10 m and preferably 3 to 4 m. By “height of the column” is meant here the height of the internal collar of the column.

In addition, each column may have a diameter of 0.25 to 6 m, preferably 0.25 to 5 m, and more preferably 0.25 to 4.5 m.

By “diameter of the column” is meant here the external diameter of the column. In the case of a column which is not cylindrical with a circular section, the diameter is understood to mean the maximum dimension of the column in a section perpendicular to its main axis. For example, for a rectangular or square section, the diameter refers to the diagonal. In the case of a frustoconical column the diameter is understood as the diameter of the large base of the column.

According to some embodiments, the height of the column (shell height) can be greater than the height of the resin bed by at least 2 m, and preferably at least 1.5 m. This feature is important for performing a resin backwash step that will allow the resin to expand in the ion exchange chromatography column (s), as described below.

Thus, as mentioned above, the ion exchange chromatography unit may include a single column ion exchange chromatography system, or a multiple column ion exchange chromatography system.

When the ion exchange chromatography unit comprises several columns, these can be arranged in series with one another. Alternatively and advantageously, when the ion exchange chromatography unit comprises several columns, the latter can be arranged in parallel with one another. In this case, at least two columns can be used simultaneously for the production of sweetened sweet juice. According to certain embodiments, part of these columns can be used for the production of sweetened sweet juice, while another part of these columns can simultaneously undergo washing steps and / or regeneration steps.

The device of the invention then comprises a collection line for sweetened sweet juice at the outlet of the ion exchange chromatography unit. The sweetened sweet juice collection line can for example transfer the sweetened juice to an evaporation unit or a tank for storing or recovering the sweetened juice.

Sugar processing process

As mentioned above, the invention also relates to a process for processing sugar. Preferably, this method is implemented in the device described above. This process is described with reference to Figure 2.

The process of the invention successively comprises:

- A first front filtration step 1 a (or first front filtration 1 a) of the sweet juice to obtain a first filtrate;

- a second front filtration step 1 b (or second front filtration 1 b) of the first filtrate to obtain a second filtrate; and

a step of bringing the second filtrate into contact with a cation exchange chromatography resin 2 so as to load the resin with divalent cations and to collect a sweetened sweet juice.

As described above, the sweet juice can be obtained by grinding (or diffusing) 3 sugar cane.

Upstream of the steps mentioned above, the process can also comprise one or more steps such as sulphitation 4, carbonation 5, clarification 6, flocculation 7, and / or decantation 8.

Downstream of the steps mentioned above, the process may include one or more steps such as evaporation 9 and / or crystallization 10.

Thus, the sweet juice undergoes a first frontal filtration 1 a, so as to obtain a first filtrate. Solid particles, especially fibrous solid particles, are retained on the filter. So these particles are separated of the sweet juice and are retained on the filter (s) used for the first filtration 1 a.

The first frontal filtration 1a can be carried out at a temperature of 75 to 98 ° C.

According to certain embodiments, this first frontal filtration 1 a allows the retention of 10 to 60% by mass of the solid particles initially found in the sweet juice.

The first filtrate comprises, for its part, the sweet juice comprising solid particles having passed through the filter (s) used for the first filtration 1a, as well as the Ca ²⁺ and / or Mg ²⁺ ions.

The first filtrate then undergoes a second filtration 1b, so as to provide a second filtrate. Solid particles, especially fibrous solid particles, are retained on the filter. Thus, these particles are separated from the sweet juice and are retained on the filter used for the second filtration 1b.

The second front filtration 1b can be carried out at a temperature of 75 to 98 ° C.

According to some embodiments, the set of the first and second frontal filtrations 1 a, 1 b allows the retention of 30 to 70% by mass of the particles initially found in the sweet juice.

The second filtrate comprises the sweet juice comprising solid particles which have passed through the filter used for the second filtration 1b, as well as the Ca ²⁺ and / or Mg ²⁺ ions.

In some embodiments, the solid particles included in the second filtrate include fine particles of bagasse.

Subsequently, the second filtrate is contacted with the cation exchange resin 2 as described above. Bringing the second filtrate into contact with the resin 2 allows adsorption of the divalent Ca ²⁺ and / or Mg ²⁺ cations on said resin. Thus, the divalent Ca ²⁺ and / or Mg ²⁺ cations present in the second filtrate are exchanged and replaced by the monovalent Na ⁺ and / or K ⁺ ions initially present on the resin. Preferably, the flow rate of the sweet juice in the ion exchange chromatography unit is 5 to 20 BV / h, and preferably 5 to 15 BV / h ("SV" corresponds to bed volume equivalents of resin from a column).

According to certain embodiments, this step can be carried out by circulating the second filtrate in the ion exchange chromatography unit in a direction from the bottom upwards in the ion exchange chromatography column (s). According to preferred embodiments, this step can be carried out by circulating the second filtrate in the ion exchange chromatography unit in a direction from top to bottom in the ion exchange chromatography column (s). .

This step can be carried out at a temperature of 75 to 98 ° C.

At the end of the step of bringing the resin into contact with the second filtrate 2, a softened sweet juice is obtained while the resin is now loaded with divalent cations.

The sweetened sweet juice obtained at the end of the step of contacting the resin with the second filtrate 2 can have a volume of 15 to 80 BV, and preferably 20 to 50 BV.

According to certain embodiments, the assembly of the first front filtration 1 a, of the second front filtration 1 b and of the contacting of the second filtrate with the resin 2 allows the retention of 50 to 90% by mass of the particles. initially found in sweet juice.

Advantageously, the sweetened sweet juice can have a Ca ²⁺ ion concentration of 5 to 150 mg / L, and preferably of 20 to 120 mg / L. Thus, this concentration can be 5 to 10 mg / L; or from 10 to 15 mg / L; or from 15 to 20 mg / L; or from 20 to 25 mg / L; or 25 to 30 mg / L; or from 30 to 35 mg / L; or from 35 to 40 mg / L; or from 40 to 45 mg / L; or 45 to 50 mg / L; or from 50 to 55 mg / L; or from 55 to 60 mg / L; or from 60 to 65 mg / L; or from 65 to 70 mg / L; or from 70 to 75 mg / L; or from 75 to 80 mg / L; or 80 to 85 mg / L; or from 85 to 90 mg / L; or 90 to 95 mg / L; or from 95 to 100 mg / L; or from 100 to 105 mg / L; or from 105 to 110 mg / L; or from 1 10 to 1 15 mg / L; or from 115 to 120 mg / L; or from 120 to 125 mg / L; or from 125 to 130 mg / L; or from 130 to 135 mg / L; or from 135 to 140 mg / L; or from 140 to 145 mg / L; or 145 to 150 mg / L.

Advantageously, the sweetened sweet juice can have a concentration of Mg ²⁺ ions of 5 to 150 mg / L, and preferably of 20 to 120 mg / L. Thus, this concentration can be 5 to 10 mg / L; or from 10 to 15 mg / L; or from 15 to 20 mg / L; or from 20 to 25 mg / L; or 25 to 30 mg / L; or from 30 to 35 mg / L; or from 35 to 40 mg / L; or from 40 to 45 mg / L; or 45 to 50 mg / L; or from 50 to 55 mg / L; or from 55 to 60 mg / L; or from 60 to 65 mg / L; or from 65 to 70 mg / L; or from 70 to 75 mg / L; or from 75 to 80 mg / L; or 80 to 85 mg / L; or from 85 to 90 mg / L; or 90 to 95 mg / L; or from 95 to 100 mg / L; or from 100 to 105 mg / L; or from 105 to 110 mg / L; or from 1 10 to 1 15 mg / L; or from 115 to 120 mg / L; or from 120 to 125 mg / L; or from 125 to 130 mg / L; or from 130 to 135 mg / L; or from 135 to 140 mg / L; or from 140 to 145 mg / L; or 145 to 150 mg / L. Advantageously, the sweetened sweet juice can have a concentration of solid particles of 1 to 100 mg / kg, and preferably of 1 to 50 mg / kg. Thus, this concentration can be from 1 to 5 mg / kg; or from 5 to 10 mg / kg; or from 10 to 15 mg / kg; or from 15 to 20 mg / kg; or from 20 to 25 mg / kg; or from 25 to 30 mg / kg; or from 30 to 35 mg / kg; or from 35 to 40 mg / kg; or from 40 to 45 mg / kg; or from 45 to 50 mg / kg; or 50 to 55 mg / kg; or from 55 to 60 mg / kg; or from 60 to 65 mg / kg; or from 65 to 70 mg / kg; or from 70 to 75 mg / kg; or from 75 to 80 mg / kg; or from 80 to 85 mg / kg; or from 85 to 90 mg / kg; or from 90 to 95 mg / kg; or 95 to 100 mg / kg.

The sweetened juice can then be evaporated 9 to reduce the amount of water in the sweetened juice. Thus, evaporation step 9 makes it possible to obtain a concentrated sweetened juice called "syrup".

Then the syrup can undergo one or more crystallizations in order to provide granulated sugar. Thus, at least one crystallization can be carried out during which the syrup is evaporated so as to be saturated with sugars and so that crystals start to form. At the end of the first crystallization 10, the crystals can be recovered and what remains of the syrup can undergo further sequential crystallizations so as to provide different grades of sugar crystals. At the end of the sequential crystallizations, what remains of the syrup is called "molasses" and can be used by the food industry, perfumery and galenic pharmacy, in biofuel production or even for resin regeneration as described above. below (arrow 12).

The loaded resin includes, at this point, an amount of sweet juice that remains in the ion exchange chromatography unit (for example, in the ion exchange chromatographic column (s)). Additionally, the ion exchange chromatography unit may include solid particles (eg, particles having a diameter of less than 50 µm), including fine bagasse particles, accumulated at the top of the resin bed.

The method according to the invention can also provide steps for regenerating the loaded resin.

However, before proceeding with the regeneration of the resin, at least one washing step can be carried out so as to remove the solid particles remaining in the ion exchange chromatography unit.

Advantageously, this washing can be carried out by injecting the washing solution from the bottom upwards into the ion exchange chromatography column (s) (thus during the washing step, the washing solution in the washing unit. ion exchange chromatography has a reverse direction than that of the second filtrate during the production of the sweetened juice). The washing solution can have a flow rate of 10 to 20 BV / h.

Thus, during this step, due to the direction of the washing solution (preferably from bottom to top) and the flow rate of the washing solution, the resin bed can undergo expansion in the chromatography unit of ion exchange. For example, in this step, the expansion of the resin bed can be at least 50% from the initial height of the bed. The resin can for example take the form of a fluidized bed. As explained above, since the solid particles remaining in the unit have a density lower than the density of the resin, they can be discharged without causing the resin particles to come out.

The washing solution can be an aqueous solution.

In some embodiments, the wash solution is water.

According to other preferred embodiments, the washing solution is obtained from the sweetened sweet juice as described above.

According to other preferred embodiments, the washing solution is obtained from the sweet juice as described above.

Different washing solutions can be used sequentially.

The washing step can be carried out in particular at a temperature of 75 to 98 ° C.

Alternatively, this washing step can be performed after the regeneration step described below or after a final rinsing step.

At the end of the washing step, a washing effluent can be collected. This effluent is a sugary aqueous solution and can, for example, be returned to clarification step 6 (arrow 1 1).

As mentioned above, the sugar treatment process according to the invention also provides steps for regenerating the resin loaded with divalent cations. Regeneration firstly comprises bringing the loaded resin into contact with a regeneration solution. At the end of the regeneration, the ion exchange resin is regenerated and a stream of aqueous solution collected at the end of the regeneration is obtained, called "regeneration effluent".

According to certain embodiments, the regeneration solution can be obtained, in whole or in part, from molasses formed after a crystallization step 10 or after several sequential crystallization steps 10 as described above (arrow 12). More particularly, the molasses formed during the crystallization of sugar (since they originate from the sweetened sweet juice) comprise monovalent ions of Na ⁺ and / or K ⁺ , at higher concentrations than sweetened sweet juice. Thus, during their passage through the ion exchange chromatography unit and their contact with the charged resin, the monovalent Na ⁺ and / or K ⁺ ions are exchanged with the divalent Ca ²⁺ and / or Mg ²⁺ of the loaded resin. The resin is thus regenerated, while the regeneration effluent comprises molasses loaded with divalent Ca ²⁺ and / or Mg ²⁺ ions which can be used and integrated in crystallization steps of a sugar production process ( arrow 13). Alternatively, these molasses loaded with Ca ²⁺ and / or Mg ²⁺ can be used for the production of ethanol. These embodiments allow regeneration of the resin without the use of chemicals such as sodium chloride.

According to other embodiments, the regeneration solution can be obtained, in whole or in part, from the sweetened sweet juice produced (arrow 14). Thus, sodium hydroxide (NaOH) or potassium hydroxide (KOH) can be added in at least part of the sweetened juice to form the regeneration solution. This solution can then pass through the ion exchange chromatography unit and therefore the charged resin so as to exchange the monovalent Na ⁺ and / or K ⁺ ions of the regeneration solution with the divalent Ca ²⁺ and / or ions. Mg ²⁺ of the loaded resin. In this case, the regeneration effluent can comprise a water-soluble compound called “calcium saccharate” formed due to the complexation of Ca ²⁺ ions with sucrose. This regeneration effluent can subsequently be used in the clarification stage 6 (arrow 15), in particular in the liming stage, which makes it possible to use less chemicals such as lime for the clarification of the juice. sugar. Thus, instead of using only a milk of lime solution, the milk of lime - calcium saccharate mixture can be mixed with the sweet juice in order to precipitate the impurities and then separate them in a decanter. The ratio of calcium supplied respectively by the milk of lime and the calcium saccharate thus formed in the mixture is from 100: 0 to 50:50. Preferably, this ratio is from 100: 0 to 80:20.

According to other embodiments, the regeneration solution can be an aqueous solution of sodium chloride referred to herein as "regeneration brine".

According to other embodiments, the regeneration solution can be an aqueous solution comprising sodium hydroxide or potassium hydroxide.

According to other embodiments, the regeneration solution can be obtained from a distillation stillage obtained from the molasses mentioned above. In Indeed, the monovalent Na ⁺ and / or K ⁺ ions present in the molasses are also present in the distillation vinasse and in similar quantities. This vinasse must first be clarified, for example with the use of a rapid separation centrifuge.

According to other embodiments, the regeneration solution may be obtained from a raffinate resulting from a treatment by chromatography of molasses, and more particularly from a raffinate obtained after a step of de-sugaring the molasses mentioned above. by chromatography. Indeed, the monovalent Na ⁺ and / or K ⁺ ions present in the molasses are also present in the raffinate and in similar amounts.

According to some embodiments, the regeneration of the resin is performed using the same regeneration solution throughout the regeneration time.

According to other embodiments, the regeneration of the resin is carried out using more than one regeneration solution during the regeneration, that is, the regeneration solution is changed during the regeneration process. For example, in the same regeneration process, a regeneration solution comprising molasses may alternate with a regeneration solution comprising sweetened sweet juice and NaOH or with a regeneration solution comprising regeneration brine.

Advantageously, the regeneration of the resin can be carried out by injecting the regeneration solution from the bottom upwards into the ion exchange chromatography column (s) (thus during the regeneration step, the regeneration solution in the (the ion exchange chromatography unit has a reverse direction than that of the second filtrate when producing the sweetened sweet juice). The regeneration solution can have a flow rate of 1 to 10 BV / h, and preferably 2 to 5 BV / h.

Alternatively, the regeneration of the resin can be carried out by injecting the regeneration solution from top to bottom into the ion exchange chromatography column (s) (thus during the regeneration step, the regeneration solution in the (ion exchange chromatography unit has the same direction as that of the second filtrate when producing the sweetened sweet juice). The regeneration solution can have a flow rate of 1 to 10 BV / h, and preferably 2 to 5 BV / h.

According to certain embodiments, when the method of the invention is implemented in the device described above, and more particularly when the step of bringing the second filtrate into contact with the resin 2 is carried out. when implemented in several ion exchange chromatography columns, a part of these columns can be used for the production of sweetened sweet juice while another part of these columns can be used for the regeneration of the loaded resin. In other words, a first part of the columns is initially used for the production of sweetened sweet juice. After a certain time, a second part of the columns resumes the production of the sweetened sweet juice while the first part of the columns is now used for the regeneration of the loaded resin.

For example, if the ion exchange chromatography unit has 15 to 20 ion exchange chromatography columns, 5 to 10 columns can be used for the production of sweetened sweet juice while 10 to 15 columns can be used for resin regeneration.

The method according to the invention can also include a final rinsing step after regeneration of the loaded resin, using a rinsing solution. Preferably, the rinse solution is sweetened sweet juice. In other embodiments, the rinse solution is water. Thus, the rinsing can be carried out by injecting the rinsing solution from the top to the bottom of the ion exchange chromatography column (s) (thus during the rinsing step, the rinsing solution injected into the unit of ion exchange chromatography has the same direction as that of the second filtrate when producing the sweetened juice).

The process according to the invention can be a continuous process.

Alternatively, the process according to the invention can be a batch process (batch).

A multi-column system as described in document WO 2007/144522 can also be cited.

The process according to the invention makes it possible to obtain sweetened sweet juice having a degree of sweetening greater than 80%. By “softening rate” is meant the ratio of the hardness of the sweetened sweet juice (at the outlet of the ion exchange unit) to the hardness of the sweet juice at the inlet of the chromatography unit d. ion exchange, the hardness corresponding to the total concentration of Ca ²⁺ and Mg ²⁺ cations.

The concentration values and concentration ratios described in the present application correspond to values averaged over a production period.

Claims

1. Process for treating sugar, comprising successively:

- a first frontal filtration (1a) of a sweet juice to obtain a first filtrate;

- a second frontal filtration (1 b) of the first filtrate to obtain a second filtrate; and

- bringing the second filtrate into contact with a cation exchange chromatography resin (2) so as to charge the resin with divalent cations and to collect a sweetened sweet juice, the resin being arranged in the form of a bed having a height h from 0.75 to 3 meters.

2. The method of claim 1, wherein the divalent cations comprise, and preferably consist essentially of Ca ²⁺ cations and / or Mg ²⁺ cations.

3. Method according to one of claims 1 to 2, wherein the sweet juice has a concentration of solid particles of 20 to 500 mg / kg, and / or a concentration of magnesium ions of 100 to 500 mg / L, and / or a calcium ion concentration of 100 to 600 mg / L.

4. Method according to one of claims 1 to 3, wherein the sweet juice has a sugar content of 10 to 20 degrees Brix, and / or a turbidity of 100 to 500 NTU.

5. Method according to one of claims 1 to 4, wherein the sweetened juice collected after the step of contacting the second filtrate with the resin (2) has a volume of 15 to 80 BV.

6. Method according to one of claims 1 to 5, wherein the first filtration (1a) allows a retention of 10 to 60% by mass of solid particles relative to the amount of solid particles present in the sweet juice, and / or the first filtration (1 a) and the second filtration (1 b) allow a retention of 30 to 70% by mass of solid particles relative to the quantity of solid particles present in the sweet juice, and / or the first filtration (1a), the second filtration (1b) and the contacting of the second filtrate with the resin (2) allow a retention of 50 to 90% by mass of solid particles relative to the amount of solid particles present in the sweet juice.

7. Method according to one of claims 1 to 6, being a batch process or a continuous process.

8. Method according to one of claims 1 to 7, comprising steps of regenerating the resin loaded with divalent cations, these steps comprising:

- bringing the loaded resin into contact with a regeneration solution;

- the collection of a regeneration effluent.

9. The method of claim 8, wherein the regeneration solution is derived from molasses formed during a crystallization step (10) of sugar, or the regeneration solution is derived in all or part of the sweetened juice, added or no sodium hydroxide or potassium hydroxide, or the regeneration solution is a regeneration brine solution comprising a chloride, or potassium or sodium salt, or the regeneration solution is obtained from a stillage from the distillation of molasses; or the regeneration solution is obtained from a raffinate resulting from a treatment by chromatography of molasses.

10. A method according to one of claims 8 or 9, wherein contacting the loaded resin with a regeneration solution comprises the use of different regeneration solutions alternating between two production cycles.

11. Method according to one of claims 8 to 10, wherein the regeneration effluent is used to perform a clarification step (6) of the sweet juice, in particular a liming step, the clarification step (6). being carried out before the first filtration (1a); or in which the regeneration effluent is used to perform one or more crystallization steps (10), the crystallization step (s) (10) being performed after the second filtrate has been brought into contact with the resin (2).

12. Method according to one of claims 1 to 11, also comprising a step of washing the resin loaded with divalent cations, or the regenerated resin, with a washing solution, the washing solution having a direction in the bed of. resin reverses to one direction of the second filtrate in the resin bed during the step of bringing the second filtrate into contact with the resin (2).

13. The method of claim 12, wherein the washing solution is from the sweetened sweet juice or the sweet juice, or the washing solution is water.

14. Method according to one of claims 12 or 13, wherein at the end of the washing step a washing effluent is collected, the washing effluent being returned to a clarification step (6) of the sweet juice, the clarification step (6) being carried out before the first filtration (1 a).

15. Method according to one of claims 1 to 14, wherein the step of bringing the second filtrate into contact with the resin (2) is carried out at a temperature equal to or greater than 75 ° C.

16. Sugar processing device, comprising:

- a supply line of a sweet juice;

- a first front filtration unit supplied by the sweet juice supply line;

- an ion exchange chromatography unit comprising a cationic resin supplied by the collection line of second filtrate, the resin having the form of a bed having a height h ranging from 0.75 to 3 meters; and

17. Device according to claim 16, wherein the first filtration unit comprises one or more screen filters, each filter having pores having a diameter of 50 to 200 µm, and preferably 80 to 120 µm.

18. Device according to claim 17, wherein the first filtration unit comprises a cleaning unit for at least one of the screen filters.

19. Device according to one of claims 16 to 18, wherein the second filtration unit comprises at least one filter basket having pores having a diameter of 20 to 100 µm, and preferably 40 to 60 µm.

20. Device according to one of claims 16 to 19, wherein the ion exchange chromatography unit comprises at least one column, preferably at least 5 columns, more preferably at least 10 columns, and further preferably at least 15 columns.

21. Device according to one of claims 16 to 20, wherein the resin bed has a diameter of 0.25 to 6 m, and preferably 0.25 to 5 m.