FR2747128A1 - PROCESS AND DEVICE FOR THE PRODUCTION OF ESTERS OF FATTY ACIDS FROM OIL SEEDS - Google Patents

Abstract

A method for making fatty acid esters from oil-containing seeds comprises the step of continuously transesterifying the seeds in a dual screw device, while simultaneously subjecting the seeds to a mechanical shearing treatment in the presence of an alcohol and a transesterification catalyst; wherein the alcohol proportion is adjusted so as to be in the range of 0.3P to 3P, with P being the alcohol proportion corresponding to the stoichiometry of the transesterification reaction: glyceride + alcohol } ester + glycerol.

Description

METHOD AND DEVICE FOR THE PRODUCTION OF ACID ESTERS
FAT FROM OIL SEEDS
The invention relates to a method for producing fatty acid esters from oil seeds such as sunflower, soybean, rapeseed, crambe, linseed, castor, sesame, cotton, copra, palm kernel, safflower, etc. By ""oleaginous" is understood to mean both the oilseeds themselves (that is to say rich in glycerides), the proteo-oleaginous seeds (that is to say, rich in glycerides and proteins), and that the seeds not especially known to be oleaginous but containing glycerides. By "seeds" is meant any type of organ of a plant in which are stored lipids (seeds, beans, seeds, pips, almonds ...).

The invention extends to a device specially designed for implementing the method.

 The traditional processes for producing fatty acid esters from oil seeds have two distinct stages: firstly an extraction of oil from the seeds and then a chemical treatment of this oil. The extraction of oil is generally carried out in presses which ensure a grinding of the seeds and an extraction of the liquid phase. An additional extraction with the solvent (hexane) is often carried out. It has been proposed to perform the extraction of oil in twin-screw devices, called extraction-pressing, configured to perform this work.

The chemical treatment of the extracted oil then consists in carrying out a transesterification of the glycerides contained therein by the reaction: glyceride + alcohol → ester + glycerol, in the presence of an acidic or basic catalyst.

 It is well known that this acid catalyzed transesterification reaction has very slow kinetics and the reactants must be brought into hot contact and generally under pressure for long periods of time (several hours). On the other hand, the transesterification by basic catalysis can be carried out more quickly but requires a refined oil, reagents and anhydrous operating conditions.

 These traditional processes are cumbersome and expensive to implement, due in part to the obligation to proceed in two distinct stages, which entails industrial costs of handling and requires more complex equipment, on the other hand, drastic conditions for carrying out transesterification (time, pressure, anhydrous character).

 Studies have been conducted to rule out some of these defects (publications: "Kevin J.

Harrington and Catherine d'Arcy-d'Evans, Transesterification in situ of sunflower seed oil, Ind. Eng. Chem. Prod. Res.

 Dev. 1985, 24, 314-318; Kevin J. Harrington and Catherine d'Arcy-d'Evans, A comparison of a conventional method of transesterification of seed oil from a series of sunflower cultivars, JAOCS, vol. 62, No. 6 June 1985, 10091013.) In these publications, it is proposed to carry out a direct transesterification of the triglycerides of the crushed seeds by macerating them in a reactor containing methanol heated to reflux, to which sulfuric acid is added. as an acidic transesterification catalyst, the duration of maceration and treatment is of the same order as that required to effect the transesterification of the oils in the traditional processes (several hours) Such a process effectively eliminates the step of extracting the the oil has several defects: firstly, the duration of the treatment is not shortened and this constraint of the traditional methods remains.It is understood that no study or test has been carried out to try to reduce this. duration because it seems to follow from the very nature of the acid-catalyzed transesterification reaction carried out, (reaction to slow tick requiring very long contact times). In addition, the process is carried out by maceration in methanol, that is to say in a large excess of alcohol: the quantities of reagents necessary are important, whereas, at the end of the reaction, it is necessary to separate the ester formed from the alcoholic medium. It should be noted that this publication mentions only methanol and ethanol as the alcohols used and, a priori, it does not seem that this process can be applied to long chain alcohols. It should also be noted that the solids (shell fragments and solid residues) remain in the medium and this process requires a separate liquid / solid separation operation at the end of the reaction.

 The aforementioned method of in situ treatment is carried out only with an acid catalyst. Indeed, it is known that the use of a basic catalyst in conventional processes entails specific constraints (need for refining the extracted oil in order to eliminate the penalizing gums in the presence of a base, very strict control the water content). The in situ process does not satisfy these constraints (since all the compounds remain in situ, in particular the gum, and it is not easy to control the water content of a medium into which seeds are directly introduced. more or less hydrated): this explains that the authors were limited to the less restrictive use of an acid catalyst; However, this use of a high concentration acid is accompanied by certain well-known disadvantages, namely degradation of the other constituents of the seed (proteins, carbohydrates) generating colored parasitic by-products and prohibiting the valorization of these other constituents. It should be noted that the in situ process using methanol leads to a slightly higher ester yield than the traditional processes (about 1% improvement); this gain is attributed by the authors to the acidity of the reactive medium (cf 1st publication, P 317, conclusions).

 The present invention proposes to provide a novel process for producing fatty acid esters from oleaginous seeds. It aims at a one-step process, benefiting from improved performance and free from some of the defects of this type of process.

 An object of the invention is in particular to provide a process leading to significantly reduced processing times compared to those of existing or proposed processes.

 Another objective is to allow the use of an acid catalyst as well as a basic catalyst (the preferred embodiment of the process of the invention providing for the use of a basic catalyst).

 Another objective is to reduce the amounts of alcohol used compared to those required in the in situ process.

 Another objective is to extend the scope of transesterification to all types of alcohols, especially long-chain alcohols, substituted or unsubstituted, congested alcohols, polyols.

 Another object of the invention is to provide a continuous process having all the advantages of continuous processes and not requiring separate operations to separate the liquid phase from the solids.

 Another objective is to provide a process that preserves the other constituents of the seed and allows their subsequent recovery, especially by fractionation.

 The process of the invention for producing fatty acid esters from oleaginous seeds is of the type in which the seeds are directly subjected to a transesterification chemical transformation in the presence of a transesterification reagent consisting of an alcohol and a transesterification catalyst; according to the present invention, this process is characterized in that the transesterification chemical transformation is carried out continuously in a twin-screw device so as to simultaneously cause the seeds to undergo a mechanical shear treatment, the alcohol and the catalyst being injected into the twin-screw device in the vicinity of the seed inlet with an adjustment of the amount of alcohol relative to the seeds such that the proportion of alcohol is substantially between 0.3P and 3P, where P is the proportion of alcohol corresponding to the stoichiometry of the transesterification reaction: glyceride + alcohol -> ester + glycerol.

 Bi-screw devices are well known in their design and used to make solid mechanical treatments, for example pressing-extraction of oil in the field concerned (or defibration of cellulosic materials in the paper industry). To the inventors' knowledge, they have not been applied to combine a mechanical shear treatment of solids and a chemical transformation of the constituents of these materials. In the process of the invention, the two chemical and mechanical treatments are carried out simultaneously and continuously in such a twin-screw device, and it is unexpectedly found that the transesterification reaction of the glycerides contained in the seeds occurs quantitatively. the liquid phase collected at the outlet no longer containing glyceride (or substantially more glyceride). It is well known that the passage times of products in twin-screw devices are relatively short (a few minutes to about ten minutes) and these results are surprising for a relatively slow kinetic reaction, and difficult to explain at present. One hypothesis is that glycerides behave differently when they are put in the presence of the alcoholic reagent at the same time they are released by the mechanical shearing action, and that they then lead to a much faster transesterification of kinetics. ; it is possible that the mechanical energies involved promote rapid access to the reactive sites of the glycerides released. It has also been found that the process retains in the ester the degree of saturation and the configuration of the starting fatty acid (monounsaturated or polyunsaturated) this is important in practice in the applications of esters (the degree saturation and the configuration of the desired ester being obtained by the choice of the starting fatty acid). In addition, the elemental analysis of the solid residue obtained (raffinate) shows that it is simply delipidated at the end of the transesterification without denaturation, with a protein enrichment for subsequent recovery.

 The process of the invention is carried out with a proportion of alcohol close to or not far from the stoichiometry which limits the amounts of reagents used and makes it much easier to purify the esters formed. Experiments show that the best results are obtained with a slight excess of alcohol relative to the stoichiometry and it will be possible advantageously to adjust the proportion of alcohol substantially between 1.05 P and 1.15 P.

 Another remarkable observation is that the process of the invention can be carried out both with an acidic catalyst and with a basic catalyst, despite the absence of control of the water content (the seeds used having hydration very different) and despite the presence of gums that do not lead to penalizing consequences. It even seems that the process gives better results with the basic catalysts and we will preferably use this type of catalysts, in particular sodium hydroxide, considering the advantages they entail (absence of degradation of proteins, lipids and other minor constituents, absence of colored parasitic by-products, ease of implementation); it is also necessary to emphasize the compatibility of the basic character with a subsequent fractionation of the secondary constituents. The favorable role of the basic nature of the catalyst can be explained by its affinity with the other hydrophilic constituents of the seed, which would limit the harmful action of water with respect to the transesterification reaction.

 The basic catalyst can be introduced in solid form into the twin-screw device which considerably simplifies its handling on an industrial scale, facilitates its dosage and limits the quantities of water introduced. The basic catalyst is advantageously injected into the twin-screw device so that the weight ratio catalyst / seed is substantially between 1% and 10%. This range of value makes it possible both to obtain a satisfactory catalysis effect and to dispose at the outlet of the twin-screw device of solids impregnated with the base under conditions making it possible to fractionate the secondary constituents of said materials and their subsequent recovery.

 The basic catalyst is preferably injected into an area of the bi-screw device located upstream of the zone where the alcohol is injected. This limits the solubilization of the lipids by the alcohol which could make the heterogeneous mixture of the various elements more difficult.

 The process of the invention leads to mass yields close to 45% (the yield being defined as the ratio of the mass of esters formed to the mass of seeds introduced).

The process of the invention is a continuous process which has on the industrial level the well-known advantages of this type of process compared to the previous processes implemented "in batch" (economy of handling, ease of automation, greater productivity). ...). The liquid phase is separated from the solids directly by the twin-screw device, the withdrawal of this phase being ensured through a filter in an end zone of the device. This regulation can be obtained by using a twin-screw device contained in a double walled tubular enclosure and by circulating in the double wall of the enclosure a thermal regulation liquid at a temperature substantially between 500
C and the reflux temperature of the alcohol used.

 Furthermore, an increase in temperature increases the kinetics of the transesterification reaction and the bi-screw device is advantageously heated to regulate the temperature of the reactive medium to a value substantially between 200 ° C. and a moderate temperature (800 to 1200 ° C.). .

 Another remarkable result of the process of the invention is that it gives good results with all the alcohols and in particular with the heavy and branched alcohols which are not usable in the traditional processes. The process of the invention thus makes it possible to extend the types of fatty acid esters that can be manufactured by its use; depending on the desired ester, it is possible in particular to choose the alcohol or a mixture of alcohol from the following group: isopropanol, butanol, hexanol, octanol, decanol, stearic alcohol, oleic alcohol, palmitic alcohol, hexadecanol, 2-ethylhexanol, propane 1,2-diol, propane-1,3-diol, butane-1,2-diol, butane-1,3-diol, butane-1,4-diol, hexane-1,6-diol, octane1,8 diol, glycerol, xylitol, sorbitol, trimethylolpropane, pentaerythritol, neopentyl glycol, ethylene glycol, polyethylene glycol.

 The bi-screw device used in the process of the invention comprises, from upstream to downstream, an area provided with shear kneaders excluding axial compression kneaders, a zone for withdrawing the liquid phase through a filter and an end zone provided with axial compression means solids before their output. It is thus avoided to carry out an oil extraction in the zone where the transesterification reaction takes place, this reaction occurring on the glycerides in situ.

The invention extends to a bi-screw device specially designed for implementing the previously defined method. This device is of the type comprising a tubular enclosure, means for thermal regulation of said enclosure, twin-screw modules with two co-connecting screws, mixing modules composed of shear disks, an input of the raw materials at the upstream end, and a solids outlet at the downstream end; according to the invention, this device is characterized in that
means for injecting a reagent and a transesterification catalyst are arranged in the vicinity of the input of raw materials,
- Liquid extraction means provided with a filter are arranged upstream of the solids outlet,
the twin-screw modules and kneading modules which are situated upstream of the withdrawal means are modules of a type suitable for subjecting the materials to shear stresses with the exclusion of significant axial compression,
- At least one twin-screw module or kneading module, mounted in reverse pitch, is disposed downstream of the withdrawal means to achieve an axial compression of solids at this level.

The invention is illustrated by the following examples which have been implemented in a bi-screw device as shown in the drawing; on this drawing
- Figure 1 is a symbolic longitudinal representation of said device.

 - Figure 2 is a cross section through a plane AA '.

 The device was made from modules marketed by the company "CLEXTRAL" (registered trademark) under the general reference "BC21". Each module comprises a tubular enclosure with double wall 1 and 2 which allows a thermal regulation of the heart of the enclosure where are housed the active organs. Some modules are of the type comprising two cohesive identical screws, others of the type comprising shear mixers composed of bilobal discs. The various modules are rotated in synchronism by an electric motor 3 to obtain a rotational speed of its output shaft of up to 600 rpm.

The device essentially comprises the following functional sections (from upstream to downstream)
a so-called impregnation section Z1, comprising an oilseed feed hopper 4, an inlet 5 for the introduction of the catalyst in the form of a solid powder, a conduit 6 equipped with a pump for the injection of the alcohol and four direct-pitch bis-screw modules such as 7,
a so-called transesterification section Z2, combining two mixing modules such as 8 located on either side of a direct-threaded twin-screw module 9,
a so-called withdrawal section Z3 comprising a liquid phase withdrawal filter 10 and three direct pitch twin-screw modules such as 11, followed by a twin-screw module with inverted pitch 12,
and a terminal section Z4 comprising a bi-screw module with a direct pitch and an output 14 of solids.

In the example, the impregnation section Z1 combines four direct-pitch bi-screw modules 7, having decreasing steps from the first to the fourth: module of the type
T2F 50 x 100 (double-threaded trapezoidal screw, length 100 mm, positive pitch 50 mm), C2F type module 33 x 100 (double-threaded conjugate screw, length 100 mm, pitch 33 mm), module type C2F 25 x 50 (twin threaded screw, length 50 mm, pitch 25 mm) and module
C2F 16 x 50 (double threaded conjugate screw, length 50 mm, positive pitch 16 mm). In addition, in this impregnation section, the catalyst inlet 5 is situated downstream of the alcohol injection pipe 6. In this section, the bi-screws with decreasing pitch perform the conveying, mixing and mixing of solids and liquids.

In the transesterification section, the bi-screw with direct pitch 9, in particular of the C2F 16 × 50 type, conveys the materials, while the two kneading modules 8 subject the materials to shear (in the absence of axial compression). ). These mixing modules are respectively of the type
MAL2 10 x 100 (45) (ten bilobal disks mounted with a pitch of 450, total length 100 mm) and type MAL2 10 x 50 (90) (ten bilobal disks mounted with a pitch of 900, total length 50 mm). In this section, transesterification takes place in situ, without significant extraction of oil (due to the absence of substantial axial compression).

 The three modules 11 of bis-screws with direct pitch of the Z3 withdrawal section are of the C2F33x50, C2F25x25, C2F16x25 type, respectively. They are followed by a C2C type double-screw bi-screw module 12. 25 x 25 (conjugated screw with 25 mm inverted pitch); this screw performs an axial compression downstream of the outlet filter 10, allowing a good extraction of the liquid phase.

 Finally, the terminal section comprises a direct pitch bi-screw module 13 of the C2F16 x 50 type for conveying solids to the outlet 14.

In the device used, temperature sensors are arranged in the different parts to provide the average temperature of the materials. Eight sensors numbered from 1 to 8 are in the examples arranged every 10 cm so as to cover the total length of the device
EXAMPLE 1
In this example, oleic sunflower seeds at 43.5% oil are used.

The weight composition in fatty acids is
palmitic acid (C16: 0): 3.50%
stearic acid (C18: 0): 3.01%
oleic acid (C18: 1): 90.808
Linoleic acid (C18: 2): 2.69
The alcohol used is 2-ethyl hexanol and the catalyst is NaOH sodium hydroxide.

The particular conditions in this example are as follows
- screw rotation speed: 300 rpm
- material flow rate: 6 kg / h
- Soda / seed ratio: 5% by weight compared to the seed
- alcohol / seed ratio: 20% by weight with respect to the seed, ie 1.P (where P is the proportion of alcohol corresponding to the stoichiometry)
the temperatures of each sensor are presented in Table 1.

<Tb>

Sensor <SEP> 1 <SEP> 2 <SEP> 3 <SEP> 4 <SEP> 5 <SEP> 6 <SEP> 7 <SEP> 8
<tb> T <SEP>("C)<SEP> 25 <SEP> 49 <SEP> 77 <SEP> 80 <SEP> 80 <SEP> 80 <SEP> 80 <SEP> 24
<Tb>
Table 1
- residence times vary between 25 s and 50 s with a maximum of 40 s
- the electrical energy consumed by the motor of 0.62 kw / h.

The filtrate is analyzed by thin-layer chromatography coupled to a flame ionization detector (quartz rods coated with silica); the eluents used for double migration are
1st migration (25 minutes): a mixture hexane 85 / diethyl ether 15 / formic acid 0.04 (v / v) for the development and quantitative analysis of mixtures of 2-ethylhexyl esters, free triglycerides and free fatty acids,
* 2nd migration (20 minutes): hexane 65 / diethyl ether 35 / formic acid 0.04) for the development and quantitative analysis of mixtures of diglycerides and monoglycerides.

 The mass composition of the filtrate is thus determined by internal calibration (cholesterol). This then makes it possible to calculate the mass yield of esters, monoglycerides and diglycerides as well as the content of free triglycerides and of free fatty acids according to the procedure described below.

* Ester yield calculation
During a time interval at, at a certain flow rate D, a mass m of seeds is introduced into the reaction tool is: m = Dt
D: seed flow in kg / h:: tool running time
m: mass of seeds introduced during zt
during this time interval at, a certain mass m2 of filtrate is recovered; the analysis of a test sample (ml) sampled in this filtrate by
CCM / DIF allows us to determine the mass of esters (mE1) present in this sample; the mass (mE2) of esters present in the filtrate recovered during the time interval tt is therefore
m2 ME2 =. Mel
ml
the ester yield of the transesterification reaction is the ratio of the mass of the ester formed to the seed mass introduced during a certain time at:
mE2
R = ~~~~ x 100
m
This yield is based on the theoretical maximum mass yield of esters which is 58.2%.

 The yields of monoglycerides and diglycerides are calculated according to a similar procedure and are respectively related to theoretical maximum yields which are 17.5 for monoglycerides and 30.5% for diglycerides.

* Determination of the content of unreacted trislycerides
. the analysis of a test sample (m1) sampled in the same filtrate by TLC / DIF allows us to determine the mass of unreacted free triglycerides present in this test portion (mTG1)
the mass (mTG2) of unreacted free triglycerides present in the filtrate recovered during the time interval is therefore
m2
mTG2 = ~~~. MTG1
mid
the content of unreacted free triglycerides is the ratio of the mass of triglycerides present in the filtrate to the mass of the filtrate
mTG2
T = ~~~~ x 100
m
This content is related to the maximum content of total triglycerides which is 43.5%.

 The content of free fatty acids is calculated according to the same procedure and is related to the theoretical maximum content which is 41.8%.

The filtrate associated with the experimental conditions of this Example No. 1 is characterized in Table 2.

<Tb>

<SEP> Yields <SEP> Massive <SEP> (%) <SEP> Content <SEP> Content <SEP> in <SEP> TG
<tb><SEP> in <SEP> AGL <SEP> free
<tb> Esters <SEP> MG <SEP> DG <SEP> (%) <SEP> (%) <SEP>
<tb> 17 <SEP> 0.02 <SEP> 4.2 <SEP> 0 <SEP> 19.5
<Tb>
Table 2
Esters: mixture of fatty acid esters of
2-ethylhexanol
MG: mixture of monoglycerides
DG: mixture of diglycerides
TG: mixture of triglycerides
AGL: free fatty acids; acid mixture
non-esterified fat.

EXAMPLE 2
In this example, oleic sunflower seeds with 43.5% oil are used.

The weight composition in fatty acids is
palmitic acid (C16: 0): 3.50%
stearic acid (C18: 0): 3.01%
oleic acid (c18: 1): 90.80%
linoleic acid (C18: 2): 2.69%.

 The alcohol used is 2-ethyl hexanol and the catalyst is NaOH sodium hydroxide.

The particular conditions in this example are as follows
- screw rotation speed: 300 rpm
- material flow rate: 3 kg / h
- soda / seed ratio: 10% by weight compared to the seed
- alcohol / seed ratio: 40% by weight with respect to the seed, ie 2 * P (where P is the proportion of alcohol corresponding to the stoichiometry)
the temperatures of each sensor are presented in Table 3.

<Tb>

t <SEP> Sensor <SEP> I <SEP> i <SEP> K2 <SEP><SEP><SEP> 3 <SEP> | <SEP> 4 <SEP><SEP> 5 <SEP> 6 <SEP> 7 <SEP> t <SEP> 8 <SEP>
<tb><SEP> T <SEP> (C) <SEP> 25 <SEP> 48 <SEP> 79 <SEP> 81 <SEP> 80 <SEP> 80 <SEP> 80 <SEP> 25
<Tb>
Table 3
- the residence times vary between 37 s and 1 min 15 with a maximum at 51 s
the electrical energy consumed by the engine is 0.64 kw / h.

The filtrate is analyzed by thin layer chromatography coupled to a flame ionization detector (silica coated quartz rod); the eluents used for double migration are
1st migration (25 minutes): a mixture of hexane 85 / diethyl ether 15 / formic acid 0.04 (v / v)
2nd migration (20 minutes): a hexane 65 / diethyl ether / 0.04 formic acid mixture.

 The mass composition of the filtrate is determined as previously by internal calibration (cholesterol), the mass yield of monoglyceride and diglyceride esters and the content of unreacted triglycerides and free fatty acids, being calculated as in the previous example.

The filtrate associated with the experimental conditions of this example No. 2 is characterized in Table 4.

<Tb>

<SEP> Yields <SEP> Massive <SEP> (%) <SEP> Content <SEP> Content <SEP> in <SEP> TG
<tb><SEP> in <SEP> AGL <SEP> free
<tb><SEP> Esters <SEP> MG <SEP> DG <SEP> (%) <SEP> (%)
<tb> 42.0 <SEP> 0 <SEP> 0 <SEP> 0 <SEP><SEP> o <SEP>
<Tb>
Table 4
Esters: mixture of fatty acid esters and
2-ethylhexanol
MG: mixture of monoglycerides
DG: mixture of diglycerides
TG: mixture of triglycerides
AGL: free fatty acids; acid mixture
non-esterified fat
With regard to the fractionation of the extrudate, the basic extraction of the proteins without the addition of sodium hydroxide in a batch reactor (extrudate / water ratio = 1/20,
T = 500C, duration 20 min, mechanical stirring) makes it possible to obtain the extraction yields presented in Table 5. For comparison, the results obtained by extraction under similar conditions of oilcake ind.

<tb><SEP> Module <SEP> of <SEP> Young <SEP> Resistance <SEP> to <SEP> 3a <SEP><SEP> Density
<tb><SEP> (N / mm) <SEP> flex <SEP> (N / cm <SEP>
<tb> Residue <SEP> solid <SEP> of
<tb> Example <SEP> n <SEP> 2 <SEP> 15 <SEP> 0.9 <SEP> 0.79
<tb> Industrial cake <SEP> industrial <SEP> 134.1 <SEP> 3,4 <SEP> 0,88
<tb> Residue
<tb> industrial meal <SEP><SEP> 59.0 <SEP> 2.6 <SEP> 0.83
<Tb>
Table 6
The results of the elemental extrudate analysis are also given in Table 7; for comparison, the results obtained for the oleic seed used for this test and for the industrial meal are presented.

<Tb>

<SEP>% <SEP> mass <SEP> C <SEP> N <SEP> H <SEP> O
<tb> Residue <SEP> Solid <SEP> of <SEP> Example <SEP>
<tb> n0 <SEP> 2 <SEP> 48.32 <SEP> 2.89 <SEP> 7.32 <SEP> 25.86
<tb> Oleic <SEP> Seed <SEP> 60.42 <SEP> 3.19 <SEP> 9.38 <SEP> 23.28
<tb> Industrial <SEP> Crab <SEP> 43.01 <SEP> 5.48 <SEP> 5.96 <SEP> 35.73
<Tb>
Table 7
EXAMPLE 3
In this example, oleic sunflower seeds at 43.5% oil are used.

The weight composition in fatty acids is
palmitic acid (C16: 0): 3.50%
stearic acid (C18: 0): 3.01%
- oleic acid (C18: 1): 90.80%
linoleic acid (C18: 2): 2.69%.

 The alcohol used is 2-ethyl hexanol and the catalyst is NaOH sodium hydroxide.

The particular conditions in this example are as follows
- screw rotation speed: 300 rpm
- material flow rate: 3 kg / h
- soda / seed ratio: 10% by weight compared to the seed
- alcohol / seed ratio: 20% by weight with respect to the seed, ie 1 * P (where P is the proportion of alcohol corresponding to the stoichiometry)
the temperatures of each sensor are presented in Table 8.

<Tb>

Sensor <SEP> 1 <SEP> 2 <SEP> 3 <SEP> 4 <SEP> | <SEP> t <SEP> | <SEP> 5 <SEP> 6 <SEP> 7 <SEP> 8
<tb><SEP> T <SEP> (C) <SEP> 25 <SEP> 49 <SEP> 79 <SEP> 79 <SEP> 80 <SEP> 79 <SEP> 79 <SEP> 24
<Tb>
Table 8
- the residence times vary between 40 s and 1 min 50 with a maximum at 1 min
- The electrical energy consumed by the engine is 0.59 kw / h.

The filtrate is analyzed by thin layer chromatography coupled to a flame ionization detector (silica coated quartz rod); the eluents used for double migration are
1st migration (25 minutes): a mixture of hexane 85 / diethyl ether 15 / formic acid 0.04 (v / v)
2nd migration (20 minutes): a hexane 65 / diethyl ether / 0.04 formic acid mixture.

The filtrate associated with the experimental conditions of this Example 3 is characterized in Table 9.

<Tb>

<SEP> Yields <SEP> Massive <SEP> (%) <SEP> Content <SEP> Content <SEP> in <SEP> TG
<tb><SEP> in <SEP> AGL <SEP> free
<tb><SEP> Esters <SEP> MG <SEP> DG <SEP> (%) <SEP> (%)
<tb> 35.2 <SEP> 0 <SEP> 0 <SEP> 0 <SEP> 0
<Tb>
Table 9
Esters: mixture of fatty acid esters and 2-ethylhexanol
MG: mixture of monoglycerides
DG: mixture of diglycerides
TG: mixture of triglycerides
AGL: free fatty acids; mixture of non-esterified fatty acids.

EXAMPLE 4
In this example, oleic sunflower seeds with 43.5% oil are used.

The weight composition in fatty acids is
palmitic acid (C16 O): 3.50%
stearic acid (C18: 0): 3.01%
oleic acid (C18: 1): 90.80%
linoleic acid (C18: 2): 2.69%.

 The alcohol used is 2-ethyl hexanol and the catalyst is NaOH sodium hydroxide.

The particular conditions in this example are as follows
- screw rotation speed: 300 rpm
- material flow rate: 3 kg / h
- soda / seed ratio: 7% by weight compared to the seed
- alcohol / seed ratio: 40% by weight with respect to the seed, ie 2 * P (where P is the proportion of alcohol corresponding to the stoichiometry)
the temperatures of each sensor are presented in Table 10

<tb><SEP> Sensor <SEP> i <SEP> 2 <SEP> 3 <SEP> 4 <SEP> 5 <SEP> 6 <SEP><SEP> 7 <SEP> 8 <SEP>
<tb> T (C) <SEP> 25 <SEP> 49 <SEP> 79 <SEP> 80 <SEP> 80 <SEP> 78 <SEP> 79 <SEP><SEP> 25 <SEP>
<Tb>
Table 10
- the residence times vary between 35 s and 1 min 15 with a maximum at 55 s
- the electrical energy consumed by the engine is 0.60 kw / h.

The filtrate is analyzed by thin layer chromatography coupled to a flame ionization detector (silica coated quartz rod); the eluents used for double migration are
1st migration (25 minutes): a mixture of hexane 85 / diethyl ether 15 / formic acid 0.04 (v / v)
2nd migration (20 minutes): a hexane 65 / diethyl ether / 0.04 formic acid mixture.

The filtrate associated with the experimental conditions of this Example 4 is characterized in Table 11.

<Tb>

<SEP> Yields <SEP> Massive <SEP> (%) <SEP> Content <SEP> Content <SEP> in <SEP> TG
<tb><SEP> in <SEP> AGL <SEP> free
<tb><SEP> Esters <SEP> MG <SEP> DG <SEP> (%) <SEP> (%)
<tb> 17.5 <SEP> 0.06 <SEP> 0.02 <SEP> 2.8 <SEP> 13.3
<Tb>
Table 11
Esters: mixture of fatty acid esters and
2-ethylhexanol
MG: mixture of monoglycerides
DG: mixture of diglycerides
TG: mixture of triglycerides
AGL: free fatty acids; acid mixture
non-esterified fat.

EXAMPLE 5
In this example, oleic sunflower seeds with 43.5% oil are used.

The weight composition in fatty acids is
palmitic acid (C16 O): 3.50%
- stearic acid (C18: 0) 3.01%
- oleic acid (c18: 1): 90.80%
linoleic acid (C18: 2): 2.69%.

 The alcohol used is 2-ethyl hexanol and the catalyst is NaOH sodium hydroxide.

The particular conditions in this example are as follows
- screw rotation speed: 300 rpm
- material flow rate: 3 kg / h
- soda / seed ratio: 7% by weight compared to the seed
- alcohol / seed ratio: 40% by weight with respect to the seed, ie 2 * P (where P is the proportion of alcohol corresponding to the stoichiometry)
the temperatures of each sensor are presented in Table 12.

<tb> Sensor <SEP> 1 <SEP> | <SEP> 2 <SEP> | <SEP> 3 <SEP> 4 <SEP> 5 <SEP> 6 <SEP> 7 <SEP> 8
<tb> T <SEP> (C) <SEP> 25 <SEP> 66 <SEP> 118 <SEP> 119 <SEP> 120 <SEP> 120 <SEP> 27 <SEP> 21
<Tb>

Table 12
- the residence times vary between 34 s and 1 min 10 with a maximum at 47 s
the electrical energy consumed by the motor is 0.87 kw / h.

The filtrate is analyzed by thin layer chromatography coupled to a flame ionization detector (silica coated quartz rod); the eluents used for double migration are
1st migration (25 minutes): a mixture of hexane 85 / diethyl ether 15 / formic acid 0.04 (v / v)
2nd migration (20 minutes): a hexane 65 / diethyl ether / 0.04 formic acid mixture.

The filtrate associated with the experimental conditions of this example is characterized in Table 13.

<Tb>

<SEP> Yields <SEP> Massive <SEP> (%) <SEP> Content <SEP> Content <SEP> in <SEP> TG
<tb><SEP> in <SEP> AGL <SEP> free
<tb><SEP> Esters <SEP> MG <SEP> DG <SEP> (%) <SEP> (%)
<tb> 30.9 <SEP> 6.8 <SEP> O <SEP> O <SEP> 29.9
<Tb>
Table 13
Esters: mixture of fatty acid esters and
2-ethylhexanol
MG: mixture of monoglycerides
DG: mixture of diglycerides
TG: mixture of triglycerides
AGL: free fatty acids; acid mixture
free fat.

EXAMPLE 6
In this example, oleic sunflower seeds with 43.5% oil are used.

The weight composition in fatty acids is
palmitic acid (C16: 0): 3.50%
- stearic acid (c18: 0): 3.01%
- oleic acid (c18: 1): 90.80%
linoleic acid (C18: 2): 2.69%.

 The alcohol used is 2-ethyl hexanol and the catalyst is NaOH sodium hydroxide.

The particular conditions in this example are as follows
- screw rotation speed: 300 rpm
- material flow rate: 3 kg / h
- soda / seed ratio: 10% by weight compared to the seed
- alcohol / seed ratio: 20% by weight with respect to the seed, ie 1 * P (where P is the proportion of alcohol corresponding to the stoichiometry)
the temperatures of each sensor are presented in Table 14

<tb> Sensor <SEP> 1 <SEP> 2 <SEP> 3 <SEP> 4 <SEP> 5 <SEP> 6 <SEP> 7 <SEP> | <SEP> 8
<tb> T <SEP>("c)<SEP> 26 <SEP> 66 <SEP> 119 <SEP> 120 <SEP> 120 <SEP> 120 <SEP> 27 <SEP> | <SEP> 22
<Tb>
Table 14
- the residence times vary between 29 s and 1 min 20 with a maximum at 50 s
- the electrical energy consumed by the engine is 1.08 kw / h.

The filtrate is analyzed by thin layer chromatography coupled to a flame ionization detector (silica coated quartz rod); the eluents used for double migration are
1st migration (25 minutes): a mixture of hexane 85 / diethyl ether 15 / formic acid 0.04 (v / v).

 2nd migration (20 minutes): a hexane 65 / diethyl ether / 0.04 formic acid mixture.

The filtrate associated with the experimental conditions of this Example 6 is characterized in Table 15.

<Tb>

<SEP> Yields <SEP> Massive <SEP> (%) <SEP> Content <SEP> Content <SEP> in <SEP> TG
<tb><SEP> in <SEP> AGL <SEP> free
<tb><SEP> Esters <SEP> MG <SEP> DG <SEP> (%) <SEP><SEP> (%) <SEP>
<tb> 31.3 <SEP> 0 <SEP> 0 <SEP> 0 <SEP> 0.005
<Tb>
Table 15
Esters: mixture of fatty acid esters and
2-ethylhexanol
MG: mixture of monoglycerides
DG: mixture of diglycerides
TG: mixture of triglycerides
AGL: free fatty acids; acid mixture
fat
EXAMPLE 7
In this example, oleic sunflower seeds with 43.5% oil are used.

The composition by weight of fatty acids is
palmitic acid (C16: 0): 3.50%
- stearic acid (c18: 0): 3.01%
oleic acid (c18: 1): 90.80%
- linoleic acid (C18: 2): 2169.

 The alcohol used is 2-ethyl hexanol and the catalyst is NaOH sodium hydroxide.

The particular conditions in this example are as follows
- screw rotation speed: 300 rpm
- material flow rate: 3 kg / h
- soda / seed ratio: 10% by weight compared to the seed
- alcohol / seed ratio: 40% by weight with respect to the seed, ie 2 * P (where P is the proportion of alcohol corresponding to the stoichiometry)
the temperatures of each sensor are presented in Table 16.

<tb> Sensor <SEP> 1 <SEP> | <SEP> 2 <SEP> | <SEP> 3 <SEP> 4 <SEP> 5 <SEP> 6 <SEP> 7 <SEP> 8
<tb><SEP> T <SEP>("c)<SEP> 26 <SEP> 66 <SEP> 119 <SEP> 121 <SEP> 120 <SEP> 120 <SEP> 28 <SEP> 22
<Tb>

Table 16
- the residence times vary between 33 s and 1 min 10 with a maximum at 46 s
the electrical energy consumed by the engine is 1.05% hw / h.

The filtrate is analyzed by thin layer chromatography coupled to a flame ionization detector (silica coated quartz rod); the eluents used for double migration are
1st migration (25 minutes): a mixture of hexane 85 / diethyl ether 15 / formic acid 0.04 (v / v)
2nd migration (20 minutes): a hexane 65 / diethyl ether / 0.04 formic acid mixture.

The filtrate associated with the experimental conditions of this Example 7 is characterized in Table 17.

<Tb>

<SEP> Yields <SEP> Massive <SEP> (%) <SEP> Content <SEP> Content <SEP> in <SEP> TG
<tb><SEP> in <SEP> AGL <SEP> free
<tb><SEP> Esters <SEP> MG <SEP> DG <SEP> (%) <SEP> (%)
<tb> 37.8 <SEP> 0 <SEP> O <SEP><SEP> 0.01 <SEP> 0
<Tb>
Table 17
Esters: mixture of fatty acid esters and
2-ethylhexanol
MG: mixture of monoglycerides
DG: mixture of diglycerides
TG: mixture of triglycerides
AGL: free fatty acids; acid mixture
non-esterified fat.

 As regards the fractionation of the extrudate, the basic extraction of the proteins without the addition of sodium hydroxide in a batch reactor (extrudate / water ratio 1/20, T = 500C, duration 20 min, mechanical stirring) makes it possible to obtain the yields Extraction data presented in Table 18. For comparison, the results obtained by extraction under similar conditions of industrial cake are also presented.

 The post-extraction lignocellulosic residue is thermopressed (1120 bar, 20 min, 1500 ° C.).

The relative mechanical properties of the material obtained on XTRAD texturometer are presented in Table 19. By way of comparison, the results obtained under the same conditions by thermopressing industrial cake and the residue of industrial cake extracted with sodium hydroxide are also presented.

<Tb>

<SEP> Potential <SEP> Protein <SEP> Extraction <SEP> Extraction
<tb><SEP> (g) <SEP> (%)
<tb> Residue <SEP> Solid <SEP> 5.78 <SEP> 95.3
<tb> of <SEP> the example
<tb> n "<SEP> 7 <SEP> 5.78 <SEP> 97.2
<tb> Crab <SEP> 16.2 <SEP> 85.5
<tb> industrial <SEP> 16.2 <SEP> 91.4
<Tb>
Table 18

<tb><SEP> Module <SEP> of <SEP> Young <SEP> Resistance <SEP> to <SEP> 3a <SEP><SEP> Density
<tb><SEP> (N / mm) <SEP> flex <SEP> (N / cm <SEP>
<tb> Residue <SEP> solid
<tb> of <SEP> Example <SEP> n "<SEP> 7 <SEP> 15 <SEP> 0.9 <SEP> 0.79
<tb> Industrial cake <SEP> industrial <SEP> 134.1 <SEP> 3,4 <SEP> 0,88
<tb> Residue
<tb> industrial meal <SEP><SEP> 59.0 <SEP> 2.6 <SEP> 0.83
<Tb>
Table 19
The results of the elemental analysis of the extrudate are also given in Table 20. For comparison, the results obtained for the oleic seed used for this test and for the industrial cake are presented.

<Tb>

<SEP>% <SEP> mass <SEP> C <SEP> N <SEP> H <SEP> O
<tb> Residue <SEP> solid <SEP> of
<tb> Example <SEP> n "<SEP> 7 <SEP> 49.91 <SEP> 3.32 <SEP> 7.52 <SEP> 25.69
<tb> Oleic <SEP> Seed <SEP> 60.42 <SEP> 3.19 <SEP> 9.38 <SEP> 23.28
<tb> Industrial <SEP> Crab <SEP> 43.01 <SEP> 5.48 <SEP> 5.96 <SEP> 35.73
<Tb>
Table 20

Claims (12)

 1 / - Process for producing fatty acid esters from oleaginous seeds, of the type in which the seeds are directly subjected to a transesterification chemical transformation in the presence of a transesterification reagent consisting of an alcohol and a transesterification catalyst, characterized in that the transesterification chemical transformation is carried out continuously in a twin-screw device so as to simultaneously effect the seeds mechanical treatment of shear, the alcohol and the catalyst being injected into the device bi-screw in the vicinity of the seed inlet with an adjustment of the amount of alcohol relative to the seeds such that the proportion of alcohol is substantially between 0.3P and 3P, where P is the corresponding proportion of alcohol at the stoichiometry of the transesterification reaction: glyceride + alcohol -> ester + glycerol.  2 / - Method according to claim 1, characterized in that the amount of alcohol injected into the twin-screw device is adjusted so that the proportion of alcohol is substantially between 1.05 P and 1.15 P.  3 / - Method according to one of claims 1 or 2, wherein using a basic catalyst, in particular sodium hydroxide.  4 / - Method according to claim 3 characterized in that the basic catalyst is injected in solid form in the twin-screw device.  5 / - Method according to one of claims 3 or 4, characterized in that the amount of catalyst injected into the twin-screw device is adjusted so that the weight ratio catalyst / seed is substantially between 1 and 10%.  6 / - Method according to one of claims 4 or 5, characterized in that the basic catalyst is injected into the twin-screw device in an area upstream of that where the alcohol is injected.  7 / - Method according to one of claims 1, 2, 3, 4, 5 or 6, wherein is used as transesterification reagent alcohol or a mixture of alcohols of the following group: isopropanol, butanol, hexanol, octanol, decanol, stearyl alcohol, oleic alcohol, palmitic alcohol, hexadecanol, 2-ethylhexanol, propane-i, 2-diol, propane-1,3-diol, butane-1,2-diol, butane-1,3-diol, butane1 , 4-diol, hexane-1,6-diol, octane-1,8-diol, glycerol, xylitol, sorbitol, trimethylolpropane, pentaerythritol, neopentyl glycol, ethylene glycol, polyethylene glycol.  8 / - Method according to one of the preceding claims, wherein using a two-screw device comprising two co-penetrating screws wrapped in a double-walled tubular enclosure, characterized in that is circulated in the double wall of the enclosure a thermal control liquid at a temperature substantially between 500 C and the reflux temperature of the alcohol used.  9 / - Method according to one of the preceding claims characterized in that a bi-screw device comprising, from upstream to downstream, an area with shear kneaders excluding axial compression kneaders, a zone withdrawing the liquid phase through a filter and an end zone provided with means for axially compressing the solids before they exit.  10 / - Method according to claim 9, characterized in that a bi-screw device comprising, upstream downstream is used  an impregnation section at which the catalyst and the transesterification reagent are injected, this section comprising screws with a direct pitch for conveying, mixing and mixing the materials,  a transesterification section along which the reaction is carried out, comprising screws with direct pitch for conveying the materials and shearing mixers of said materials,  a draw-off section comprising screws with direct pitch for conveying the materials and a filter for withdrawing the liquid phase,  - A terminal section comprising screws with inverted pitch or kneader mounted in not inverted to subject the material to an axial compression, and screws with a direct pitch for conveying the materials to the outlet.  11 / - A method according to claim 10, characterized in that a bi-screw device is used in which the impregnation section and the withdrawal portion comprise a plurality of different pitch screws decreasing downstream.  12 / - bi-screw device specially designed for implementing the method according to one of the preceding claims, of the type comprising a tubular enclosure (1, 2), thermal regulation means of said enclosure, bi-modular modules screw with two co-entrant screws (7,9,11,12,13), mixing modules (8) composed of shear disks, a raw material inlet (4) at an upstream end, and a solids outlet ( 14) at a downstream end, characterized in that  means (5, 6) for injecting a reagent and a transesterification catalyst are arranged in the vicinity of the input of raw materials,  means (10) for extracting liquid provided with a filter are arranged upstream of the solids outlet,  the twin-screw modules (7, 9) and kneading modules (8) which are located upstream of the withdrawal means (10) are modules of a type suitable for subjecting the materials to shear stresses at the exclusion of significant axial compression,  - At least one twin-screw module or kneading module, mounted in reverse pitch (12), is disposed downstream of the withdrawal means to achieve an axial compression of solids at this level.