Process for the cryo-crystallization of oils and fats for applications in the food, cosmetics and pharmaceutical industries

Abstract

A method for manufacturing solid particles (13), from a liquid or semi-liquid composition (1), in particular from a composition of oil, a grease, a wax or another greasy compound, using at least one device (2) for forming a liquid or semi-liquid jet of the product, then a step of total or partial freezing or crystallization of the jet thus formed, characterized by the implementation of the following measures: one or more streams (12) of the composition are produced using the forming device(s), entering the upper part of a reaction chamber (3) and circulating within this reaction chamber from top to bottom; the reaction chamber is supplied with cryogenic liquid (4) to create a cold gas atmosphere within the reaction chamber; the particles formed are recovered in the lower part (5) of the chamber;characterized in that an apparatus is used for cutting the said product stream(s), using a wire or disc (14) rotating at a given and chosen speed, the passage of the wire or disc making it possible to cause the cutting of substantially cylindrical particles of the product, transforming into spherical or substantially spherical particles during their fall within the chamber towards the lower part of the chamber where they are recovered (5°. Figure 3;

Description

Title of the invention: Process for the cryo-crystallization of oils and fats for applications in the fields of agri-food, cosmetics and pharmacy

[0001] The present invention relates to the field of processes and equipment dedicated to the cryo-crystallization of oils and fats or other liquid or semi-liquid greasy compounds, with a high melting point, for applications in the fields of agri-food, cosmetics or even pharmacy.

[0002] State-of-the-art cryo-crystallization equipment makes it possible, as is known, to transform an oil, a grease, a wax or other greasy compound containing a certain proportion of active ingredient into a set of solid particles in the form of powder or beads.

[0003] The following documents illustrate the very abundant and sometimes old literature which has been devoted to this question: EP-919 279, EP-0393 963, US-4 655 047, GB-2 092 880, WO99 / 33555, or US-4 982 577, or even EP-1 285 584.

[0004] In the context of the present invention, we are interested in so-called "mono-dispersed" or "monodisperse" particles, that is to say particles whose size is substantially the same, not giving rise to the production of aggregations, double or triple particles, or even particles that are too small ("satellites"), particles that are too small which are a major drawback for certain applications, in particular pharmaceutical applications, and the elimination of which then constitutes a major challenge.

[0005] This physical transformation (into particles) mentioned above is sought after in many fields such as nutrition, animal feed, cosmetics and pharmaceutical products. It offers many advantages such as: • easier dosing of the products making up an industrial recipe, • better flow of the product, • easy storage, • better resistance to compaction and mass recovery, • as well as an increase in service life.

[0006] A cryo-crystallization process then classically consists of atomizing the molten product in a cooled enclosure using a cryogenic fluid, typically liquid nitrogen, which causes a sudden cooling of the particles in free fall in the enclosure, up to the point of crystallization. The transformation is irreversible and the collected product remains in the crystallized state in the form of a powder or small balls depending on the spraying technology implemented in the device.

[0007] The attached [Fig.l] illustrates by a partial schematic view the different parts of a typical state-of-the-art cryo-crystallization device.

[0008] Let us explain how this equipment works: the products previously melted and contained in the tank 1 are conveyed into the injection equipment 2 located in the upper part of an enclosure 3 cooled using a liquid nitrogen spray 4, in atomized form or in the form of drops depending on the method which has been chosen to fractionate the product to be transformed.

[0009] Remarkably, the refrigerating energy developed by the liquid nitrogen allows almost immediate freezing of the grease particles as they fall into the cooling chamber. The powder or balls thus formed are recovered frozen in the lower part of the enclosure in a collection device 5.

[0010] There are generally two types of implementation of the injection of the molten product, the choice of which depends on the type of transformation desired (types recalled in [Fig.2] attached).

[0011] The first process ((a) - pneumatic injection) is undoubtedly considered less qualitative than the second ((b), injection called "electro-spray") but makes it possible to achieve significant productivities, typically of the order of 1000 kg / h. On the other hand, the particle size distribution is wide with a significant proportion of fine particles requiring careful filtration of the extracted gas flow, or even an "ATEX" classification of the production installation.

[0012] In demanding fields such as pharmacy or cosmetology, transformation into mono-dispersed beads (also called monodisperse) is often required. The formation of fine particles is then avoided by the preferred application of the second process, to the detriment of productivity. Indeed, as has been said, the latter is limited to approximately 200 kg / h, with a growth potential limited to the maximum number of needles implantable in the injection head. In addition, the productivity of the system is sensitive to the surface tension of the product.

[0013] In the case of products with low surface tension such as surfactants, the product flow rate is limited. This type of injection does not allow the transformation of products having a surface tension greater than 0.07 N / m corresponding to highly hydrated products. This sensitivity to the surface tension of the product implies a different configuration and productivity from one product to another, which can be very restrictive for production sites processing different types of product.

[0014] In the prior art, the production of mono-dispersed beads with higher productivity then requires the purchase of several machines, which can slow down investment decisions and the adoption of the technology by the manufacturer.

[0015] As will be seen in more detail below, the present invention proposes to replace the electro-spray device conventionally implanted until now in cryo-crystallization devices, with a more productive device for generating monodisperse beads, while maintaining a high level of quality of the processed product.

[0016] It is then proposed here to implement a method of cutting a liquid jet coming for example from a nozzle or even from a syringe for producing this jet, using a rotating wire or disk rotating at high speed (in the industry we sometimes speak of “jet cutting”).

[0017] The attached [Fig.3] illustrates by a partial schematic view the principle of func operation of such a wire cut, we recognize in [Fig.3] the following elements: 10: arrival of liquid product (composition) to be treated 11: an engine 12: the jet / stream of liquid produced 13: particles produced downstream of the cutting disc or wire (14).

[0018] The passage of the wire or disc (14) at the level of the liquid jet of product causes the cutting of cylinders which transform into spherical balls during their fall.

[0019] The typical range of ball diameters that can be envisaged with this method typically ranges from 0.2 mm to 3 mm, the quantity of balls generated per second depends on the rotation frequency of the cutting wire, generally from 5000 to 10,000 Hz but can go up to 25,000 Hz.

[0020] For example, for a diameter of 3 mm and at the maximum frequency of 25,000 Hz, productivity can reach 1200 kg / h, a value 5 to 6 times higher than that achievable in electro-spray.

[0021] Furthermore, this productivity is not affected by the surface tension of the product, nor by its density or dynamic viscosity. The announced performances can thus be achieved even for products having a very low surface tension, less than 20 mN / m for example for surfactants.

[0022] According to a preferred embodiment of the invention, the cutting device mentioned above is installed in the upper part of a cryo-crystallization apparatus, in particular between the reservoir containing the molten product and the cooling enclosure, or in the upper part of this enclosure.

[0023] The attached [Fig.4] illustrates by a partial schematic view an example of implementation of the invention with such an implantation of the cutting system within a cryo-crystallizer.

[0024] The nozzle is fed at a constant flow rate from the pressurized product reservoir, ensuring, by the rotation at constant speed of the cutting wire, a very tight ball size distribution.

[0025] Advantageously, as seen in [Fig. 4], the system can be equipped with one, two or more nozzles for producing a jet 12 of liquid to be treated (to be cut), fed preferentially with the same flow rate, multiple nozzle system thereby increasing the number of balls generated per unit time. The productivity thus obtained can be high even for a ball diameter of less than 3 mm.

[0026] The use, in accordance with the invention, of wire or disc cutting in cryo-crystallization constitutes a notable advance compared to the state of the art; it allows the production of monodisperse balls of oils, fats, waxes or other compounds, with a diameter greater than one mm, in greater quantity and the quality of which is at least equivalent to that obtained with the previous processes.

[0027] Because in fact, the refrigerating power provided by the use of a liquid cryogen such as liquid nitrogen allows the complete crystallization of the product over a reduced height, typically around 2 m on state-of-the-art devices, compared to prior art systems equipped with conventional vapor compression refrigerating circuits whose height can reach 5 to 10 meters.

[0028] The present invention then relates to a method for manufacturing solid particles, from a liquid or semi-liquid composition, in particular from a composition of oil, a grease, a wax or another greasy compound, using at least one device for forming a liquid or semi-liquid jet of the product, for example such as from a nozzle or a syringe, then a step of total or partial freezing or crystallization of the jet thus formed, characterized by the implementation of the following measures: - one or more streams of the composition are produced using the formation device(s), entering the upper part of a reaction chamber and circulating within this reaction chamber from top to bottom; - the reaction chamber is supplied with cryogenic liquid, for example liquid nitrogen, to create a cold gas atmosphere within the reaction chamber; - the particles formed are recovered in the lower part of the chamber;

[0029] characterized in that an apparatus is used for cutting said product stream(s), using a wire or disc rotating at a given and chosen speed, said apparatus positioned downstream of the outlet of said product stream(s) from said forming device(s), preferably positioned in the upper part of the chamber, the passage of the wire or disc making it possible to cause the cutting of substantially cylindrical particles of the product, transforming into spherical or substantially spherical particles during their fall within the chamber towards the lower part of the chamber where they are recovered.

[0030] The present invention also relates to an installation for manufacturing solid particles, from a liquid or semi-liquid composition, in particular from a composition of oil, grease, wax or other greasy compound, comprising: - a reaction chamber; - at least one device for forming a liquid or semi-liquid jet of the composition, for example such as from a nozzle or a syringe, device capable of producing one or more streams of the composition, entering the upper part of the reaction chamber and circulating within this reaction chamber from top to bottom; - means for supplying the reaction chamber with cryogenic liquid, for example liquid nitrogen, to create a cold gas atmosphere within the reaction chamber and thus enable total or partial freezing or crystallization of the stream(s) thus formed; - means of recovery in the lower part of the chamber of the particles formed;

[0031] characterized in that the installation comprises an apparatus for cutting said product stream(s), using a wire or disc capable of rotating at a given and chosen speed, apparatus positioned downstream of the outlet of said product stream(s) from said forming device(s), preferably positioned in the upper part of the chamber, the passage of the wire or disc making it possible to cause the cutting of substantially cylindrical particles of the product, transforming into spherical or substantially spherical particles during their fall within the chamber towards the lower part of the chamber where they are recovered using said recovery means.

Claims

Claims

1. A method for manufacturing solid particles (13), from a liquid or semi-liquid composition (1), in particular from a composition of oil, a grease, a wax or another greasy compound, using at least one device (2) for forming a liquid or semi-liquid jet of the composition, for example such as from a nozzle or a syringe, then a step of total or partial freezing or crystallization of the jet thus formed, characterized by the implementation of the following measures: - one or more streams (12) of the composition are produced using the formation device(s), entering the upper part of a reaction chamber (3) and circulating within this reaction chamber from top to bottom; - the reaction chamber is supplied with cryogenic liquid (4), for example liquid nitrogen, to create a cold gas atmosphere within the reaction chamber; - the particles formed are recovered in the lower part (5) of the chamber; characterized in that an apparatus is used for cutting said product stream(s), using a wire or disc (14) rotating at a given and chosen speed, apparatus positioned downstream of the outlet of said product stream(s) from said forming device(s), preferably positioned in the upper part of the chamber, the passage of the wire or disc making it possible to cause the cutting of substantially cylindrical particles of the product, transforming into spherical or substantially spherical particles during their fall within the chamber towards the lower part of the chamber where they are recovered (5).

2. A plant for manufacturing solid particles (13), from a liquid or semi-liquid composition (1), in particular from a composition of oil, grease, wax or other greasy compound, comprising: - a reaction chamber (3); at least one device for forming a liquid or semi-liquid jet liquid of the composition, for example such as from a nozzle or even a syringe, capable of producing one or more streams (12) of the composition, entering the upper part of the reaction chamber and circulating within this reaction chamber from top to bottom; - means for supplying the reaction chamber with cryogenic liquid (4), for example liquid nitrogen, to create a cold gas atmosphere within the reaction chamber and thus enable total or partial freezing or crystallization of the stream(s) thus formed; - means for recovering (5) the formed particles in the lower part of the chamber; characterized in that the installation comprises an apparatus (14) for cutting said composition stream(s), using a wire or disc capable of rotating at a given and chosen speed, apparatus positioned downstream of the outlet of said product stream(s) from said forming device(s), preferably positioned in the upper part of the chamber, the passage of the wire or disc making it possible to cause the cutting of substantially cylindrical particles of the product, transforming into spherical or substantially spherical particles during their fall within the chamber towards the lower part of the chamber where they are recovered using said recovery means (5).

Images