FR3047996A1 - USE OF A REACTOR IN A SOAP MANUFACTURING PROCESS AND REACTOR SPECIALLY ADAPTED FOR SUCH USE - Google Patents

Abstract

Use of a reactor (1) in a soap-making process, the reactor (1) comprising a vessel (2) having an interior space (5) and a stirring system (10) movable in the interior space ( 5) of the tank (2), the manufacturing process being discontinuous and comprising at least one pasting and baking step providing for a mixture of at least one fatty substance and a base in the interior space ( 5) of the vat (2), and heating the mixture, wherein during the mashing and baking step, the stirring system (10) is moved into the mixture so as to circulate the mixture. mix and shear at least locally the mixture.

Description

The invention relates to a use of a reactor in a soap-making process and to a reactor specially adapted for such use. The invention applies to a discontinuous soap manufacturing process (also called "batch" or in the tank) in which the soap is manufactured in discrete batches from reagents placed in specified quantities in a tank of specific capacity.

Such a manufacturing process comprises in particular a pasting and baking step during which a saponification reaction occurs to form alkaline salts (carboxylates), constituting the soap, and glycerine. In particular, the pasting and baking step provides for a mixture of one or more fatty substances, such as an oil and for example a vegetable oil, and a base, such as sodium hydroxide (NaOH ) to obtain a so-called "hard" soap or potash (KOH) to obtain a so-called "soft" soap, in the tank. The mixture is heated to initiate the saponification reaction.

The saponification reaction is exothermic and difficult to control. In particular, the mixture has a viscosity which increases rapidly then continues to increase but more slowly. The mixture then has a heterogeneity likely to lead to a buildup in certain areas of the mixture and a runaway reaction. To avoid caking in the mixture and the runaway of the reaction, it is known to introduce the base in several times during the pasting and baking step.

In addition, the saponification reaction is favored when the fatty substance and the base form an emulsion. To facilitate formation of an emulsion, it is known to use, during the pasting and baking step, an additional reagent acting as a surfactant, such as a soap base derived from a previous implementation of the soap manufacturing process. Π is also known to work at boiling to promote mixing.

These arrangements for forming an emulsion while avoiding caking in the mixture and the runaway of the reaction lead to a complex soap making process and long to implement. In addition, the use of an additional reagent and, in particular a soap base, leads to the introduction of impurities in the mixture that may alter the properties of the soap and, in particular, its color and smell. The invention aims to overcome the problems mentioned above. For this purpose, according to a first aspect, the invention proposes a use of a reactor in a soap manufacturing process, the reactor comprising a vessel having an interior space, the manufacturing process being discontinuous and comprising at least one step of mashing and baking providing a mixture of at least one fatty substance and a base in the interior space of the vessel, and heating the mixture, wherein the reactor further comprises a movable stirring system in the interior space of the tank so as to circulate the mixture in the interior space of the tank, and to shear at least locally the mixture, and wherein, in the manufacturing process, during step d The cooking and stirring system is moved in the mixture so as to circulate the mixture in the interior space of the tank and shear at least locally the mixture.

Thus, the use of the reactor according to the invention, the stirring system of which combines a circulation and a shear, makes it possible to ensure the homogeneity of the mixture, whatever the viscosity of the mixture during the manufacturing process. . The setting in mass in the mixture as well as the runaway of the reaction can thus be avoided in particular without it being necessary to introduce the base in several times. The stirring system according to the invention which implements a shear also makes it possible to reduce a droplet size of fat and base bodies forming an emulsion and thus to increase an exchange surface between the fatty substance and the base. In this case, it is no longer necessary to use an additional reagent to facilitate the formation of the emulsion. The soap manufacturing process is simplified and its duration of implementation reduced. In addition, the properties of the soap can be preserved.

As is apparent from the foregoing, the use of the reactor according to the invention makes it possible to ensure better contacting of the reagents used in the soap manufacturing process, so that it is possible to reduce the excess of base, and that it is possible to reduce the contact time between the reagents and the temperatures of implementation. In particular, it is no longer necessary to work on a boil. In addition to simplifying and reducing its implementation time, the manufacturing process may have a more favorable environmental balance, in particular because of the reduction in energy requirements and the quantity of reagents required. The invention can make it possible to benefit from such advantages for a set of different stages of the soap manufacturing process by carrying out these steps in the same reactor. In this respect, the use of the reactor is particularly advantageous in a soap manufacturing process which, particularly after the mashing and baking step, involves at least one washing step in the course of which an aqueous solution loaded with electrolytes, is added to the mixture. During the washing step, the stirring system can then be moved in the mixture so as to circulate the mixture and shear at least locally the mixture. The use of the reactor may also be provided in a soap manufacturing process implementing, after the washing step, a smoothing step to obtain a homogeneous soap paste, having controlled water and electrolyte contents to allow its subsequent drying and shaping. During the smoothing step, the stirring system can then be moved into the mixture so as to circulate the mixture and shear at least locally the mixture. The use of the reactor according to the invention applies, in particular, to the method of manufacturing Marseille soap. Marseille soap is a high quality soap obtained by a traditional batch process. The term "Marseille soap" is not a controlled appellation of origin and has no official definition, but corresponds to a manufacturing process, and includes essential steps. The method of manufacture of Marseille soap is generally accepted as being based on the historical stages of pasting / cooking, salting / washing (one or more steps) and smoothing, to ensure that smooth crystalline phase comprising at least 63% of fatty acids.

The terms of pasting and cooking constitute the two stages of the saponification reaction: the pasting designates the start of the saponification reaction, and the baking is aimed at following the reaction, kinetically slower, allowing the complete saponification . In the pasting and baking step of the Marseille soap production process, a mixture of a fatty substance and an aqueous sodium hydroxide solution is produced and heated.

The terms "salting out" and "washing" both refer to the same operation, the term "salting out" being generally used to designate the first step of washing the obtained soap paste, allowing the removal of part of the impurities and glycerin. In the salting / washing step of the soap making process

Marseille, an aqueous solution loaded with electrolytes is added to the mixture which is heated with stirring, and then left to settle (without stirring) until two phases are formed: a grainy soap including in particular electrolytes, and an aqueous solution including in particular electrolytes and glycerine. In a particular embodiment, during the washing step of the Marseille soap manufacturing method, an aqueous solution comprising 1 to 42% by weight of a mixture of sodium hydroxide and salt may be added to the mixture. The mixture is heated with stirring and then left to settle, hot without stirring, until two phases are formed: the grained soap comprising salt, sodium hydroxide and glycerine, and an aqueous solution comprising salt and sodium hydroxide. and glycerine. The use of the stirring system according to the invention can advantageously be implemented during this salting / washing step to create a dispersion bringing into intimate contact the two immiscible phases and of different densities over the entire reaction volume. At the end of the washing step, the soap has an inhomogeneous grained appearance due to the presence of significant amounts of electrolytes. This grained soap is not "processable", that is to say that it can not be shaped to obtain, for example soap bars that can be stored and marketed. The step of smoothing the Marseille soap manufacturing process is then implemented on the grained soap to obtain a smooth soap. In a particular embodiment, the step of smoothing the manufacturing process of Marseille soap can be carried out by neutralization. The grained soap is then mixed with at least one neutralizing agent, such as an acid, a fatty acid or a fatty acid ester, and heated with stirring.

The stirring system may comprise at least one first stirring member adapted to shear the mixture and at least one second stirring member adapted to move the mixture in a pumping direction, the first stirring member being arranged downstream. the second stirring member with respect to the pumping direction. In the manufacturing process, the mixture can be moved in the pumping direction by the second stirring member to the first stirring member and sheared by the first stirring member.

The tank may comprise a cylindrical side wall along a central axis, the second stirring member being arranged so that the pumping direction is along the central axis of the tank, the first stirring member being further adapted to move the mixing transversely with respect to the central axis to the side wall. In the manufacturing process, the mixture can be moved along the central axis of the vessel by the second stirring member and moved transversely relative to the central axis to the side wall by the first stirring member.

The tank may comprise a bottom from which the side wall extends, the first stirring member being arranged near the bottom of the tank, the second stirring member being arranged at a distance from the bottom of the tank. In the manufacturing process, the mixture can be moved to the bottom of the tank by the second stirring member and moved to the side wall near the bottom of the tank by the first stirring member.

The tank may have a circular cross-section and at least one of the first and second stirring members may be a movable having a hub and a plurality of equally-distributed blades each extending from the hub to a free end, the hub of the mobile being pivotally mounted relative to the tank along a pivot axis coaxial with the central axis.

The first stirring member may be a mobile with radial pumping and the second stirring member may be an axially pumped mobile. The radial pumping mobile allows local creation of speed gradients rather than pumping the mixture. The mobile axial pumping is, meanwhile, shearing but promotes circulation.

The mobile radial pump of the first stirring member may have a first power number Pol between 1.5 and 6 where

with D diameter of the mobile, in meters, p viscosity of the mixture, in Pascals / second, PI power dissipated in the tank by the first stirring member, in

watts,

No rotational speed of the first stirring member, in revolutions / second, and in which the axially pumped mobile of the second stirring member has a second pumping number Qo2 between 0.5 and 2 where

with Q2, in cubic meters / second, flow passing through a projected surface in a plane perpendicular to the axis of pivoting of the second stirring member.

The mobile may have a diameter of between 40% and 80%, preferably between 50% and 70%, of the diameter of the cross section of the tank.

The first stirring member may be a mobile, each blade has a lower edge facing the bottom of the tank, the lower edge of each of the blades being shaped to have a substantially constant spacing with a portion of the bottom of the tank on a whole essential part, that is to say 50% or more, of a length of said blade.

The stirring system may comprise at least one deflection member, such as a counter-blade or, in Anglo-Saxon terms, a baffle, arranged near the side wall facing the second stirring member to deflect a part of the mixture located near the side wall to the second stirring member. In the manufacturing process, an upper part of the mixture located near the side wall can be diverted to the second stirring member by the deflection member.

According to a second aspect, the invention provides a reactor specially adapted for use as defined above, comprising a vessel having an interior space and a stirring system movable in the interior space of the tank so as to circulate a mixture of at least one fatty substance and a base in the interior space of the tank, and shear at least locally the mixture. Other objects and advantages of the invention will appear on reading the following description of a particular embodiment of the invention given by way of non-limiting example, the description being made with reference to the appended drawing in which the figure is a schematic representation in partial section of a reactor according to an embodiment used in a soap manufacturing process, the reactor comprising a vessel and a stirring system movable in the interior space of the vessel.

The figure represents a reactor 1 for use in a soap making process. In particular, as will become apparent in the following description, the soap manufacturing process provides for a mixture of reagents during different steps to obtain soap.

The reactor 1 comprises a tank 2 having a bottom 3 from which a side wall 4 extends to delimit an interior space 5. In the embodiment shown, the bottom 3 is elliptical and the cylindrical side wall 4 of circular cross section according to a central axis A. The inner space 5 has a diameter T and a filling level H. The tank 2 can be dimensioned so that an H / T ratio is between 1.5 and 5. At the opposite of the bottom 3, the tank 2 has an upper opening 6. The upper opening 6 can be closed by a cover 8. In particular, the cover 8 can be mounted on an edge of the upper opening 6 non-hermetically to be able to achieve tank mixtures 2 called "open", that is to say whose inner space 5 is at atmospheric pressure.

Alternatively, the tank 2 could have any other suitable shape with preferably a non-flat bottom 3 and in particular a conical bottom.

The tank 2 may be equipped with a heating system not shown. In particular, the tank 2 may have a bottom 3 and a sidewall 4 jacketed envelope connected to a source of fluid supply at a suitable temperature.

The reactor 1 further comprises a stirring system 10 adapted to circulate the mixture in the interior space 5 of the tank 2, and to shear at least locally the mixture.

In the embodiment shown, the stirring system 10 comprises a shaft 11 extending along the central axis A in the interior space 5 of the tank 2 and through the cover 8. The shaft 11 has a first end 11a connected to a rotary drive device, such as a geared motor 12, and a second end 11b disposed in the vicinity of the bottom 3 of the tank 2. The shaft 11 can thus be driven in its own rotation along an axis of pivoting P coaxial with the central axis A by the drive device 12. The drive device 12 may in particular be adapted to drive the shaft 11 in its own rotation at a speed of rotation of up to 80 rpm or more.

The stirring system 10 also comprises a first stirring member 15 mounted on the shaft 11 in the vicinity of the second end 11b. The first stirring member 15 is then pivotally mounted along the pivot axis P with respect to the vessel 2.

The first stirring member 15, arranged near the bottom 3 of the tank 2, is adapted to shear the mixture, that is to say locally create speed gradients, and to move the mixture transversely relative to the central axis A to the side wall 4. The first stirring member 15 may be a mobile radial pump, such as a mobile with straight blades. In particular, the mobile of the first stirring member 15 comprises a hub 16 integral with the shaft 11, and several blades 17, in particular four in the embodiment shown, equidistributed and each extending from the hub 16 to a free end 18. Each of the blades 17 is straight, that is to say that it extends in a plane containing the pivot axis P. The mobile of the first stirring member 15 may have a diameter D between 40% and 80%, preferably between 50% and 70%, of the diameter T of the internal space 5 of the tank 2.

The shape of the mobile of the first stirring member 15 may also be adapted to follow the shape of the bottom 3 of the vessel 2. In particular, each of the blades 17 may have a lower edge 19 facing the bottom 3 of the vessel 2 shaped to have a spacing substantially constant cl with a portion of the bottom 3 of the tank 2 on an essential part, that is to say 50% or more, a length of the blade 17 measured between the hub 16 and the free end 18. The spacing c between the lower edge 19 of each of the blades 17 and the bottom 3 of the tank 2 may be between 5% and 20% of the diameter T of the internal space 5 of the tank 2.

The mobile of the first stirring member 15 has: a first power number

with p viscosity of the mixture, in Pascals / second, PI power dissipated in the tank by the first stirring member 15, in

watts,

No rotational speed of the first stirring member 15, in revolutions / second, - a first pumping number

with Ql, in cubic meters / second, flow passing through a projected surface in a plane perpendicular to the pivot axis P of the first stirring member 15.

The first power number Pol of the mobile radial pump of the first stirring member 15 is high, for example between 1.5 and 6, so as to promote shearing. The first pumping number Qol of the radial pumping mobile of the first stirring member 15 may be low, for example between 0.2 and 1. o

The power dissipated per cubic meter of mixture is between 1000 W / m and 8000 W / m3, preferably between 2000 W / m3 and 6000 W / m3.

Alternatively, the mobile of the first stirring member 15 could be a Rushton turbine or other mobile radial flow.

The stirring system 10 also comprises a second stirring member 25 mounted on the shaft 11 on the side of the first end 11a, below the filling level H. The second stirring member 25 is then arranged coaxially with the above the first stirring member 15. The second stirring member 15 is thus pivotally mounted along the pivot axis P with respect to the vessel 2.

The second stirring member 25, arranged at a distance from the bottom 3 of the tank 2, is adapted to move the mixture in a pumping direction S, indicated by an arrow in the figure. In the embodiment shown, so that the mixture can be moved to the first stirring member 15, the pumping direction S is along the central axis A of the vessel 2 and oriented towards the bottom 3 of the vessel 2. The second stirring member 20 may be a descending axial pumping mobile, such as a propeller with inclined blades. In particular, the mobile of the second stirring member 25 comprises a hub 26 integral with the shaft 11, and several blades 27, in particular four in the embodiment shown, equidistributed and each extending from the hub 26 to a free end 28. Each of the blades 27 is inclined, that is to say it deviates from a plane containing the pivot axis P. The blade 27 has a median plane relative to the lower edges 29 and upper 30 opposed along the axis of pivoting P. The median plane is at an angle with the plane containing the pivot axis P. This angle is, for example, 45 ° in the figure with an inclination such that the edge upper 30 is in front of the lower edge 29 with respect to a direction of rotation R of the shaft 11, represented by an arrow, and therefore of the mobile of the second stirring member 25. In the embodiment shown, the moving part of the second stirring member 25 a diameter D identical to that mobile of the first stirring member 15. Alternatively, the mobile of the second stirring member 25 could have any other diameter between 40% and 80%, preferably between 50% and 70%, of the diameter T of the interior space 5 of the tank 2.

The mobile of the second stirring member 25 has: a second power number

with P2 power dissipated in the tank by the second stirring member 25, in Watts, N2 rotational speed of the second stirring member 25, revolutions / second, - a second number of pumping

with Q2, in cubic meters / second, flow passing through a projected surface in a plane perpendicular to the pivot axis P of the second stirring member 25.

The second pumping number of the axially pumped mobile of the second stirring member is high, for example between 0.5 and 2, so as to promote circulation. The second power number of the axially pumped mobile of the second stirring member may be low, for example between 0.3 and 1.5. at

The dissipated power per cubic meter of mixture between 1000 W / m and 8000 W / m3, preferably between 2000 W / m3 and 6000 W / m3. The invention is not limited to the agitation system 10 described above and could in particular include any other type of stirring member, in appropriate number, in particular between two and five, preferably between two and three, and in any case appropriate arrangement. For example, the stirring system 10 could comprise two second stirring members, for example identical, mounted coaxially on the shaft above the first stirring member.

The stirring system 10 may also comprise one or more deflection members 35, for example between two and four, preferably between two and three, arranged to deflect a portion of the mixture located near the side wall 4 of the tank 2 to the second or the second stirring member 25. The deflection members 35 can be removably mounted in the inner space 5 of the tank 2. In the embodiment shown, as deflection members 35, the stirring system 10 comprises two counter-blades 36 or, in Anglo-Saxon terms, baffles, arranged near the side wall 4 of the tank 2 facing the free ends of the mobiles of the second stirring members 25. The counter-blades 36 can be removable and pivotable about a longitudinal axis L to allow to change an orientation. The counter-blades 36 may have a width lb of between 3% and 8% of the diameter T of the internal space 5 of the tank 2. Furthermore, the counter-blades 36 may be arranged so as to leave a free space with the side wall 4 of the tank 2 between 2% and 8% of the diameter T of the internal space 5 of the tank 2.

According to the arrangement proposed in the particular embodiment, the radial pumping mobile of the first stirring member 15 is disposed downstream of the axially pumping mobile of the second stirring member 25 with respect to the pumping direction S. The mixture can thus be moved in the direction of pumping S along the central axis A to the bottom 3 of the tank 2 by the axially pumped mobile of the second stirring member 25 to the radial pumping mobile of the first stirring member 15 and sheared and displaced transversely with respect to the central axis A to the side wall 4 by the radial pumping mobile of the first stirring member 15. The mixture can thus return to the axially pumped mobile of the second stirring member 25 being deflected towards this mobile by the counter-blades 36.

Without being limited thereto, reactor 1 described above can be used in a batch type soap manufacturing process. Batch process (also called "batch" or in the form of a vessel), as used herein, is understood to mean a process in which the soap is manufactured in discrete batches from reagents placed in specified quantities in the tank 2 of determined capacity. as opposed to continuous processes based on a metering pump system which continuously feed the reactor with reagents. The batch process is preferably implemented in the tank 2 of the reactor 1 open, that is to say not hermetic. Preferably, in the batch process of the invention, the various stages are conducted at atmospheric pressure, in the presence of air. The invention is illustrated in greater detail in the following illustrative and nonlimiting example.

EXAMPLE

In the particular example, the tank 2, also known under the name cauldron in the context of the manufacture of Marseille soap, has a capacity of 7 T has a diameter T of 2 m and a filling level H of 4m.

The mobile of the first stirring member 15 has a diameter D of 1.4 m. The blades 17 of the mobile of the first stirring member 15, four in number, have a lower edge 19 conforming to the elliptical shape of the bottom 3 of the tank 2 and spaced therefrom with a spacing of 5 cm. The blades 17 of the mobile of the first stirring member 15 have a height wl measured along the pivot axis of 0.35 m. The first power number Pol is 3 and the first pump number Qol is 1.

The mobile of the second stirring member 25 is placed 2 m "center to center" above the mobile of the first stirring member 15. The mobile of the second stirring member 25 has a diameter D of 1.4 m. The blades 27 of the mobile of the second stirring member 25, four in number and inclined at 45 °, have a height w2 measured along the pivot axis P of 0.21 m. The second power number Po2 is 1.5 and the second pump number Q02 is 0.8.

The reactor is equipped with two counter-blades 36 (or baffles) of height Hb of 1.5 m covering substantially the right part of the filling level H, and of width lb 0.1 m.

Without being limited thereto, the use of the reactor 1 is now described in connection with a method of manufacturing Marseille soap. Reactor 1 could, however, be used in any other soap making process.

Milling and baking

The manufacturing method can implement at least one step a. mashing and cooking in which: at least one fatty acid and / or fatty acid ester is mixed with an aqueous sodium hydroxide solution, the mixture is heated to obtain a soap paste, the mashing and baking step implements the saponification reaction itself.

In this step, at least one fatty acid and / or fatty acid ester is mixed with an aqueous solution of sodium hydroxide and optionally with brine (an aqueous solution comprising at least 3.5% by weight of sodium chloride (NaCl) preferably between 10 and 30% NaCl).

By fatty acid is meant carboxylic acids comprising a hydrocarbon radical, saturated or unsaturated, linear or branched, comprising 6 to 30 carbon atoms, and preferably 12 to 22 carbon atoms. Examples of saturated fatty acids that may be mentioned are caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tricecylic acid, myristic acid, pentadecyl acid, palmitic acid, margaric acid, stearic acid, nonadecylic acid, eicosanoic acid, behenic acid, tetracosanoic acid, and their mixtures. By way of example of unsaturated fatty acids, mention may be made of sorbic acid, decylenic acid, caproleic acid, undecylenic acid, lauroleic acid, myristoleic acid, pentadecenoic acid, palmitoleic acid, palmiteaic acid, oleic acid, elaidic acid and acid. vaccenic, linoleic acid, gamma-linolenic acid, alpha-linolenic acid, steradonic acid, parinaric acid or stearidonic acid, gadoleic acid, dihomo-linoleic acid, dihomo-gamma-linolenic acid, arachidonic acid, timnodonic acid or eicosapentaenoic acid, erucic acid, acid brassic acid, cetoleic acid, adrenic acid, clupanodonic acid, docosahexaenoic acid, nervonic acid or selacholeic acid, eicosadienoic acid, eicosatrienoic acid, docosadienoic acid, docosatetraenoic acid, docosapentaenoic acid. The fatty acid and / or the fatty acid ester used in step a. is usually contained in a fatty substance, preferably of vegetable origin.

Thus, the fatty acid and / or the fatty acid ester used in step a. may be a fatty substance, more preferably, the fatty substance is an oil or a pasty vegetable or plant origin. According to the criteria of some soap makers, the name "Marseille soap" may indeed require the exclusive implementation of vegetable or vegetable fats.

The term "oil" any lipophilic compound, nonionic, insoluble in water and liquid at room temperature (25 ° C) and at atmospheric pressure (760 mmHg, 101 325 Pa). For the purposes of the present invention, the term "insoluble in water" means a compound whose solubility at spontaneous pH in water at 25 ° C. and at atmospheric pressure is less than 1%, and preferably less than 0.5%. in weight. The oils preferably have a viscosity of less than 500 cPs at 25 ° C at a shear rate of 1 sec -1.

Paste means any lipophilic compound, nonionic, insoluble in water and semi-solid or solid at room temperature (25 ° C) and at atmospheric pressure. The pastes preferably have a viscosity of greater than 500 cPs at 25 ° C at a shear rate of 1 sec -1.

In particular, the fatty substance comprising the fatty acid and / or the fatty acid ester is extracted from a species belonging to the plant kingdom. As an example of a fatty substance that can be used in the compositions of the invention, mention may be made of sweet almond oil, argan oil, avocado oil, peanut oil, lemon camellia oil, safflower oil, calophyllum oil, rapeseed oil, coconut oil, coriander oil, pumpkin oil, wheat germ oil, lemon oil jojoba oil or liquid jojoba wax, linseed oil, macadamia oil, corn germ oil, hazelnut oil, walnut oil, vernonia oil, apricot kernel oil, olive oil, especially olive-pomace oil, evening primrose oil, palm oil, passionflower oil, pomace oil grape, rose oil, castor oil, rye oil, sesame oil, rice bran oil, soybean oil, and sunflower oil.

Among the fatty substances mentioned above, it is preferable to use olive oil, in particular acid olive pomace oil, coconut oil, palm oil, or a mixture of these oils. this. The expression "acid olive pomace oil" may refer to an acid oil obtained from olive pomace. Such an oil may, for example, be derived from the acid hydrolysis of the neutralization pastes obtained during the refining of olive-pomace oil intended for feeding. Indeed, during the refining of olive-pomace oil, one step is to neutralize the free fatty acids by adding sodium hydroxide. An oil free of free fatty acids is obtained on one side (for food use) and sodium salts of fatty acids and thus neutralization pastes on the other. It is these neutralization pastes which are then re-acidified to obtain oil: the acid oil of pomace. Any other method of manufacturing acid oil from olive pomace known to those skilled in the art can also be envisaged.

The fatty substances and in particular the oils and pastes used in the process of the invention can be refined, in order to limit the impurities introduced into the soap during step a., Which could impact the odor, the color and the dermatological qualities of the final soap. Refining consists of removing the metals (P, Ca, Mg, Zn, Cu, Fe) naturally present in the oil. Refining also eliminates pigments, impurities that can impart bad odor, color and quality to soap, as well as traces of pesticides. Refining can consist in the neutralization of fatty acids by addition of sodium hydroxide or distillation, washing with water and drying, discoloration on activated charcoal, steam deodorization, filtrations ...

The aqueous sodium hydroxide solution implemented in step a. preferably comprises 20% to 31% by weight of sodium hydroxide, preferably 25% to 30% by weight.

The amount of aqueous sodium hydroxide solution is preferably adjusted in step a. to be in excess of less than 5% relative to the stoichiometry, more preferably less than 2%, more preferably less than 1%, so as to ensure the saponification of all the fatty acids and / or esters of fatty acid used in the process.

The amount of brine optionally introduced in step a. may especially be between 0.1 and 5% by weight of the mixture of step a.

Thus, the mixture of fatty substance and aqueous sodium hydroxide solution is preferably composed of: 60 to 70% by weight of fatty substance, preferably 63 to 68% by weight, 25 to 40% by weight of aqueous sodium hydroxide solution, preferably 29 to 36% by weight, 0.5 to 5% by weight of brine, preferably 1 to 3% by weight.

The mixture is heated to a temperature between 75 and 99 ° C, preferably between 80 ° C and 90 ° C, for a period of 1h to 6h, preferably 2h to 5h.

The heating makes it possible to initiate the saponification reaction. The saponification reaction is then exothermic, the temperature required in step a. is maintained between 75 and 99 ° C, preferably by means of a thermostatically controlled reactor, said reactor can for example be double jacket and heat insulated, in order to optimize energy consumption.

The amount of sodium hydroxide present in the reaction medium of step a. is controlled by assay (titration of the base contained in the soap, therefore the sodium hydroxide, with an acid, here hydrochloric acid, after solubilization of the soap in hot ethanol, according to the standard NFT60-306 - determination of the caustic free alkali content), allowing a monitoring of the progress of the reaction. It is indeed essential to ensure that all the fat has been saponified since any unsaponified triglycerides could oxidize and become rancid, thus affecting the color and smell of the final soap.

The reactor, for shearing and pumping simultaneously, ensures an intimate mixture of the fatty acid and / or the fatty acid ester with the aqueous sodium hydroxide solution, which makes it possible to avoid the setting zones. and the risks of runaway reaction and guarantee the homogeneity and quality of the dough. In addition, it is no longer necessary to introduce a soap base from a previous manufacture to allow the emulsion, which is ensured mechanically, which limits the introduction of impurities into the soap. The homogeneity of the mixture being guaranteed, the soda can be introduced in a substantially stoichiometric amount (less than 5% excess sodium hydroxide), and introduced at one time (against several incremental additions in the traditional process). At the end of step a., A soap paste comprising a mixture of sodium carboxylates, that is to say salts of fatty acids constituting soap, soda and water and glycerin.

Relargase / washing

The manufacturing method can implement at least one step b. release / washing of the soap paste obtained in step a. wherein: the soap paste is mixed with an aqueous solution comprising 1 to 42% by weight of a mixture of sodium hydroxide and salt, the mixture is heated, and left to settle until formation of two phases: the grained soap comprising salt, sodium hydroxide and glycerine, and an aqueous solution comprising salt, sodium hydroxide and glycerin, the grained soap and the aqueous solution are separated.

The grained soap obtained in step b. includes salt and soda, and glycerin. The salting / washing step is decisive in the process of the invention. The inventors have indeed optimized this step to allow to keep a controlled amount of glycerin, preferably between 1 and 8% by weight of the smooth soap obtained after a single washing step, preferably between 2 and 5% by weight.

Thus, the soap paste resulting from step a. is mixed with an aqueous solution comprising: 1 to 7% by weight of salt, preferably 2 to 5% by weight of salt, more preferably 2 to 4% by weight of salt, and 0.01% to 40% by weight of salt; sodium hydroxide, preferably from 0.9% to 20% by weight of sodium hydroxide, more preferably from 2% to 8% by weight of sodium hydroxide.

The salt and sodium content may be adjusted by those skilled in the art depending on the nature of the oils used for the manufacture of the soap and the desired glycerin content in the final soap.

The traditional methods of soap manufacture recommend using as much water as fatty substances for washing the soap paste to allow a good separation of the soap and the aqueous solution comprising salt, sodium hydroxide and sodium hydroxide. glycerin. Due to the particular electrolyte composition of the washing solution implemented in step b. of the process of the invention, it is possible to effectively wash the soap paste from step a. without the need to use too much water.

Thus, the weight ratio of the aqueous washing solution implemented in step b. on the fatty acids and / or fatty acid esters introduced in step a. is less than 1, preferably between 0.2 and 0.99, and more preferably between 0.3 and 0.6.

The aqueous washing solution implemented in step b. may be added to the soap paste resulting from step a., in the same reactor equipped with a mechanical stirring system as that used for step a. As for step a., The presence of the mechanical stirring system, simultaneously shearing and pumping, ensures an intimate mixing of the soap with the washing solution, thereby reducing the duration of the step. salting / washing and the temperatures used and to limit the amount of washing water required. Thus energy consumption and rejects are reduced and the quality of the soap is preserved by a limited heating time and mild temperatures.

Thus, during step b., The mixture is heated to a temperature between 70 and 99 ° C, preferably between 80 and 99 ° C for 30 minutes to 2 days, preferably for 45 minutes to 24 hours, and more preferably during lh to 18h.

The mixture can then be left to settle, for example between 30 minutes and 24 hours.

The decantation can be carried out in two stages: the mixture is left to settle for 30 minutes at 6 o'clock, more preferably 1 h to 4 h, and a first racking makes it possible to recover the aqueous solution having decanted, the soap mixture is again allowed to decant for 6h to 2 days, preferably for 8 to 23h, more preferably 12 to 18h and a second withdrawal allows to separate the grained soap from the aqueous solution comprising salt, sodium hydroxide and glycerine.

The yield in aqueous washing solution, expressed as a mass of aqueous solution withdrawn on mass of aqueous washing solution (including water + electrolytes) introduced in step b. release / washing allows to characterize the effectiveness of the settling. The yield of aqueous washing solution in step b. is preferably greater than 60%, preferably between 75 and 99.5%, and more preferably between 85 and 95%.

Thus, by optimizing on the one hand the composition of the aqueous washing solution and its quantity and, on the other hand, the operating parameters, in particular by the use of an appropriate stirring system, it has been possible to limit significantly the number of washing steps compared to traditional soap-making processes that require between 4 and 6 salting / washing steps.

Thus, the method can implement at most two steps b. washing, preferably at most one step b. washing.

Water consumption and discharges of washings are reduced accordingly. The result is a more environmentally friendly and less energy-consuming process that preserves the quality of the soap with mild temperatures and reduced heating times.

smooth

Finally, the soap manufacturing process may comprise at least one step of smoothing the grained soap obtained in step b. by neutralization in which: the grained soap is mixed with at least one neutralizing agent which may be an acid, a fatty acid or a fatty acid ester, the mixture is heated and the smooth soap is obtained.

In traditional processes, the introduction of salt water during the various stages of release / washing allows the soap to be separated from aqueous washing solutions containing in particular impurities, sodium hydroxide and glycerin, but the washed soap has a content of salt (NaCl) too high to allow its shaping. It is therefore necessary to reduce the level of salt in the soap. To do this, the soap is generally smoothed by liquidation, that is to say by adding pure water. This step causes the formation of an intermediate phase of soap solubilized in water called black fat. This partial solubilization of the soap affects the yields of the reaction, affecting the productivity of the process and creates discharges to be reprocessed.

By introducing into the aqueous washing solution, a mixture of salt and sodium hydroxide in a controlled content, it is thus possible to effectively separate the soap aqueous washing solutions without forming black fat during the smoothing step and solubilize a fraction of the glycerine. It is thus possible to obtain a soap free of impurities while retaining some of the glycerin resulting from the saponification.

To obtain a smooth, processable soap, that is to say, which can be dried and shaped, the smooth soap should preferably comprise less than 33% by weight of water, less than 0.7% by weight of salt and less than 0.2% by weight of free sodium hydroxide (in NaOH form). The manufacturing method can therefore implement a neutralization smoothing step in particular to reduce the sodium content of the soap.

The grained soap is thus mixed with at least one neutralizing agent which may be an acid, a fatty acid or a fatty acid ester. The use of an acid or a fatty acid allows the rapid neutralization of soda by acid-base reaction. The use of a fatty acid ester allows a slower neutralization of sodium hydroxide by saponification.

Preferably the neutralizing agent is a fatty acid or a fatty acid ester.

By fatty acid is meant carboxylic acids comprising a hydrocarbon radical, saturated or unsaturated, linear or branched, comprising 6 to 30 carbon atoms, and preferably 12 to 22 carbon atoms. Examples of saturated fatty acids that may be mentioned are caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tricecylic acid, myristic acid, pentadecyl acid, palmitic acid, margaric acid, stearic acid, nonadecylic acid, eicosanoic acid, behenic acid, tetracosanoic acid, and their mixtures.

Preferably, the saturated fatty acids are selected from caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and mixtures thereof. By way of example of unsaturated fatty acids, mention may be made of sorbic acid, decylenic acid, caproleic acid, undecylenic acid, lauroleic acid, myristoleic acid, pentadecenoic acid, palmitoleic acid, palmiteaic acid, oleic acid, elaidic acid and acid. vaccenic, linoleic acid, gamma-linolenic acid, alpha-linolenic acid, steradonic acid, parinaric acid or stearidonic acid, gadoleic acid, dihomo-linoleic acid, dihomo-gamma-linolenic acid, arachidonic acid, timnodonic acid or eicosapentaenoic acid, erucic acid, acid brassic acid, cetoleic acid, adrenic acid, clupanodonic acid, docosahexaenoic acid, nervonic acid or selacholeic acid, eicosadienoic acid, eicosatrienoic acid, docosadienoic acid, docosatetraenoic acid, doco s apentaenoic acid.

Preferably, unsaturated fatty acids are selected from palmitoleic acid, oleic acid, linoleic acid, and mixtures thereof.

The fatty acid esters are preferably those previously described for use in step a. pasting / cooking, in particular fatty substances, and in particular the oils described above. Step c. smoothing can be implemented with a mixture of saturated and unsaturated fatty acids, preferably derived from vegetable fats such as for example olive oil, coconut oil or palm oil . Preferably, the fatty substances used in step c. smoothing are derived from the same plant species as those used for saponification during step a.

Thus, during step c., The mixture is heated to a temperature between 70 and 99 ° C, preferably between 80 and 99 ° C for 10min to 5h, preferably for 30min to 2h.

The smoothing implemented in step c. is carried out in the same reactor equipped with a mechanical stirring system as that used for steps a or b. As for the steps a. and b., the presence of a mechanical stirring system, simultaneously shearing and pumping, ensures an intimate mixture of the grained soap with the fatty acid, allowing effective neutralization of the soda contained in the grained soap, this which makes it possible to reduce the duration of the smoothing step and the temperatures used. The homogeneity ensured, the reduced durations and temperatures make it possible to ensure the good quality of the soap. The use of the reactor ensures the homogeneity of the mixture throughout the soap manufacturing process.

This reduces the water consumption, the contact time between the reagents and the reaction temperatures. As a result: step a. mashing / baking can be conducted at temperatures between 75 and 99 ° C for a period about half as long as traditional methods, step b. Release / wash may be conducted at temperatures between 70 and 99 ° C, and the number of washes and the amount of wash water may be reduced.

These milder operating conditions therefore make it possible to reduce energy consumption and waste. And they also make it possible to guarantee the integrity of the fatty substances or oils of high quality used and to limit the formation of impurities resulting from the degradation of these oils or fats at high temperature and thus to ensure the good quality of the Soap Drying and finishing Step c. the process of the invention may be followed by a step of drying the smooth soap to obtain a soap comprising at most 22% by weight of water, preferably at most 16% by weight of water.

Drying can preferably be accomplished by passing the smooth soap into a vacuum atomizer in which the soap is sprayed. Any other system using natural or forced convection, heated or not, ambient air or a carrier gas can also be used as a means of drying. So the soap can for example also be poured on the ground and dried in the open air

Once dried, the soap can be shaped, for example, by passing through series extruders in which it is compressed. Then the soap comes out of the extruders through a die that allows obtaining the desired shape for the finished product. Π may alternatively be shaped by cutting, for example when the soap has been dried on the ground in particular. The soap can also be shaped by molding.

Soap

A smooth soap capable of being manufactured by means of the discontinuous soap manufacturing process according to the example described above preferably comprises: at most 33% by weight of water, preferably 25% to 33% by weight, more preferably 24% to 32% by weight of water, at most 0.7% by weight of salt, preferably 0.1% to 0.6%, more preferably 0.2% to 0.5% by weight of salt, and at most 0.2% by weight of sodium hydroxide, preferably 0.05% to 0.2%, more preferably 0.05% to 0.1% by weight of free sodium hydroxide (in NaOH form). The invention is illustrated in greater detail in the following illustrative and nonlimiting example.

EXAMPLE

A smooth soap was prepared according to the following method:

360g of olive-pomace oil, 120g of coconut oil and 120g of palm oil were introduced into a jacketed reactor equipped with a mechanical stirring system allowing the mixture to be simultaneously sheared and pumped. Stirring is started at a speed of 500 rpm. The reactor is heated to a temperature of 78 ° C.

326 g of an aqueous solution of 27% sodium hydroxide and 2.1% of brine are added at once to the reactor.

The mixture is stirred at 650 rpm at a temperature of 87 ° C. for 4 h 30 min.

The determination of the sodium hydroxide by titration with hydrochloric acid after 4:30 has confirmed that the saponification reaction is complete.

197 g of an aqueous solution comprising 5% of salt and 6.8% of sodium hydroxide were then introduced into the reactor, still with stirring at 650 rpm at a temperature of 87 ° C., and stirring was maintained at this temperature for 35 minutes. .

After 35 minutes the stirring was stopped, and the mixture was allowed to settle for 1 h until at least two phases were formed at 87 ° C.

The detergent was then withdrawn including water, sodium hydroxide and salt and glycerine. It was allowed to settle again for 1 hour at 87 ° C. and then the lye containing water, sodium hydroxide and salt and glycerine was again withdrawn. 139g of leached solids were thus recovered.

The yield is therefore 70.55%.

The soap was then smoothed. To do this, 24.7 g of coconut oil was introduced into the jacketed reactor equipped with a stirring system containing the grained soap previously obtained.

The mixture is stirred at 650 rpm at a temperature of 95 ° C. for 30 min.

The smooth soap is then poured and dried in the open air

The soap obtained is perfectly homogeneous and can benefit from the name Marseille soap. Π forms a particularly creamy foam, and moisturizing glycerin protects the skin.

Claims (13)

1. Use of a reactor (1) in a soap manufacturing process, the reactor (1) comprising a vessel (2) having an interior space (5), the manufacturing process being discontinuous and comprising at least one step of mashing and baking providing a mixture of at least one fatty substance and a base in the interior space (5) of the vat (2), and heating the mixture, the use being characterized in that that the reactor (1) further comprises a stirring system (10) movable in the interior space (5) of the tank (2) so as to circulate the mixture in the interior space (5) of the tank (2), and at least locally shearing the mixture, and in that in the manufacturing process, during the mashing and baking step, the stirring system (10) is moved into the mixture so as to circulate the mixture in the interior space (5) of the tank (2) and to shear at the m oins locally the mixture. 2. Use according to claim 1, wherein the manufacturing process comprises at least one washing step providing for adding to the mixture an aqueous solution loaded with electrolytes, and wherein, in the manufacturing process, during the step washing, the stirring system (10) is moved in the mixture so as to circulate the mixture and to shear at least locally the mixture. 3. Use according to claim 2, wherein the manufacturing process comprises, after the washing step, a smoothing step, and wherein in the manufacturing process, during the washing step, the cleaning system is The stirring is moved in the mixture so as to circulate the mixture and to shear at least locally the mixture. 4. Use according to any one of claims 1 to 3, wherein the stirring system (10) comprises at least a first stirring member (15) adapted to shear the mixture and at least a second stirring member (25) adapted to move the mixture in a pumping direction (S), the first stirring member (15) being arranged downstream of the second stirring member (25) with respect to the pumping direction (S), and in which, in the manufacturing process, the mixture is moved in the pumping direction (S) by the second stirring member (25) to the first stirring member (15) and sheared by the first stirring member (15). 5. Use according to claim 4, wherein the vessel (2) has a cylindrical side wall (4) along a central axis (A), the second stirring member (25) being arranged so that the direction of pumping (S ) along the central axis (A) of the tank (2), the first stirring member (15) being further adapted to move the mixture transversely with respect to the central axis (A) towards the side wall ( 4), and in which, in the manufacturing process, the mixture is displaced along the central axis (A) of the tank (2) by the second stirring member (25) and displaced transversely with respect to the axis central (A) to the side wall (4) by the first stirring member (15). 6. Use according to claim 5, wherein the tank (2) has a bottom (3) from which the side wall (4) extends, the first stirring member (15) being arranged near the bottom (3). ) of the tank (2), the second stirring member (25) being arranged at a distance from the bottom (3) of the tank (2), and wherein, in the manufacturing process, the mixture is moved towards the bottom (3) of the tank (2) by the second stirring member (25) and moved to the side wall (4) near the bottom (3) of the tank (2) by the first stirring member (15). ). 7. Use according to any one of claims 5 and 6, wherein the vessel (2) has a circular cross section and at least one of the first (15) and second (25) stirring members is a mobile comprising a hub (16, 26) and a plurality of equally distributed blades (17, 27) each extending from the hub (16, 26) to a free end (18, 28), the hub (16, 26) of the mobile being pivotally mounted relative to the tank (2) along a pivot axis (P) coaxial with the central axis (A). 8. Use according to claim 7, wherein the first stirring member (15) is a radially pumped mobile and the second stirring member (25) is an axially pumped mobile. 9. Use according to claim 8, wherein the mobile radial pump of the first stirring member (15) has a first power number Pol between 1.5 and 6 where with D diameter of the mobile, in meters, p viscosity of the mixture, in Pascals / second, PI power dissipated in the tank by the first stirring member (15), in Watts, Ni speed of rotation of the first stirring member ( 15), in revolutions / second, and in which the axially pumped mobile of the second stirring member (25) has a second pumping number Qo2 between 0.5 and 2 where with Q2, in cubic meters / second, flow passing through a projected surface in a plane perpendicular to the pivot axis (P) of the second stirring member (25). 10. Use according to any one of claims 7 to 9, wherein the mobile has a diameter of between 40% and 80%, preferably between 50% and 70%, of the diameter (T) of the cross section of the tank. (2). 11. Use according to any one of claims 7 to 10 when dependent on claim 6, wherein the first stirring member (15) is a mobile, each blade (17) has a lower edge (19). facing the bottom (3) of the tank (2), the lower edge (19) of each of the blades (17) being shaped to have a spacing (cl) substantially constant with a portion of the bottom (3) of the tank ( 2) on an essential part of a length of said blade (17). 12. Use according to any one of claims 5 to 11, wherein the stirring system (10) comprises at least one deflection member (35) arranged near the side wall (4) facing the second member d agitator (25) for diverting a portion of the mixture located near the side wall (4) to the second stirring member (25), and wherein in the manufacturing process, a portion of the mixture located near the the side wall (4) is deflected towards the second stirring member (25) by the deflection member (35). 13. Reactor (1) specially adapted for use according to any one of claims 1 to 12, comprising a tank (2) having an interior space (5) and a stirring system (10) movable in the interior space (5) of the tank (2) so as to circulate a mixture of at least one fatty substance and a base in the interior space (5) of the tank (2), and to shear at least locally the mixed.