WO2011117540A1

WO2011117540A1 - Module for the continuous conversion of at least one fluid product, and associated unit and method

Info

Publication number: WO2011117540A1
Application number: PCT/FR2011/050618
Authority: WO
Inventors: Pascal Pitiot
Original assignee: Rhodia Operations
Priority date: 2010-03-23
Filing date: 2011-03-23
Publication date: 2011-09-29

Abstract

This module has a housing (22) and at least a first tube (26A) for conversion of the product. The first tube (26A) comprises an inlet (52A) for injecting a product, an intermediate region (44A) in the form of a helix arranged in the chamber, and an outlet (54A) for collecting the converted product. The first tube (26A) defines a continuous internal channel (51) for the circulation of the product between the injection inlet (52A) and the collecting outlet (54A), the injection inlet (52A) and the collecting outlet (54A) protruding from the chamber (22). In the intermediate region (44A), the ratio of the radius of the helix to the maximum transverse span of the internal channel (51) is between 20 and 100, and advantageously lower, between 20 and 70.

Description

Module for continuous transformation of at least one fluid product, unit and associated process

The present invention relates to a module for continuous transformation of at least one fluid product, of the type comprising:

- a speaker ;

at least one first product transformation tube, the first tube comprising a product injection inlet, a helical intermediate region disposed in the enclosure, and a processed product recovery outlet, the first tube defining a continuous internal lumen of product flow between the injection inlet and the recovery outlet, the injection inlet and the recovery outlet projecting out of the enclosure.

Such a module is suitable for forming, for example, a reactor intended to carry out a chemical reaction on a fluid product, such as a homogeneous or heterogeneous liquid, a liquid-liquid dispersion, a gas-liquid dispersion, a liquid-solid dispersion or a solid-liquid dispersion dispersion. supercritical fluid.

More generally, the transformation may be a physical transformation, in particular a thermal transformation that may be accompanied by a chemistry, and / or a chemical transformation. It may involve one or more liquid, solid or gaseous products.

In a nonlimiting manner, this transformation can be a chemical reaction of the conventional type using, for example, at least one reagent.

The module and the associated processing unit are intended in particular to be used on a laboratory scale to determine the parameters constituting the transformation, with a view to extrapolating this transformation on a larger scale, and in particular to pilot or industrial scale.

The parameters of the transformation include flow properties, eg pressure drop, axial and radial dispersion, viscosity, rheology, partition coefficient or other parameters.

The parameters of the transformation are also in a nonlimiting manner, the kinetics of chemical reaction in a homogeneous or heterogeneous medium, the conditions making it possible to obtain an optimum of yield for chemical reactions or physical transformations, reaction or reaction enthalpies, the temporal processes of chemical and physical reactions.

The module according to the invention is advantageously used to study reactions such as esterifications, emulsion polymerizations, bulk polymerizations, radical polymerizations, nitrations, controlled oxidation, oxidation, hydroxylation, nitration, fluorination, chlorination, phosgenation, hydrogenation, amonolysis, epoxidation, hydrolysis, hydrocyanation, hydrochlorination, sulfonation, sulfonylation, phosphatation, etc.

This module is particularly advantageous for the implementation of selective reactions in which it is useful to minimize a parasitic chemistry, and for kinetic reactions of order greater than or equal to 2 in which the residence time and therefore the volume of the reactor must be minimal to given production.

During the development process of a chemical or physical transformation, it is known to carry out small-scale tests, for example in "batch", "semi-batch" or continuous type reactors.

These small-scale tests make it possible to quickly evaluate the interest and the feasibility of the transformation, at a lower cost, and with an optimal safety, because of the small quantities of reagents involved.

Once the transformation parameters have been optimized at the laboratory scale, their transposition on an industrial scale is sometimes difficult.

In the first place, industrial plants have dimensions and structure that differ considerably from laboratory facilities. In addition, the mass transfer and heat exchange conditions are generally very different in an industrial environment. In the context of continuous flows, the dimensions of industrial reactors render these flows most often turbulent, but not necessarily, whereas they are often laminar at the laboratory scale.

It is therefore often necessary to carry out numerous simulations, pilot scale tests, and then on an industrial scale to optimize the implementation of the transformation process.

These extrapolation steps are expensive and delay the development of an industrial process. In addition, in some cases, the extrapolated method may have a significantly lower yield than initially expected from laboratory tests, which may make the initially planned solution totally inoperative or unprofitable.

The parameters of the transformation to be determined at the laboratory scale are in particular the flow properties defined above, the selectivity of the transformation, especially in the presence of possible parasitic chemistries, and the maximum conversion that can be expected.

For this purpose, laboratory reactors of the aforementioned type are known in which a helical tube is placed in a water bath to perform a chemical reaction.

Such reactors, however, are not satisfactory. Indeed, because of the laminar flow of the reagent in the reactor, the mixture in the reactor is not always satisfactory, which results in a distribution of residence times not necessarily controlled, because of axial and / or radial dispersions and the existence of potential dead volumes. In the case where parasitic chemistries appear, the product obtained at the outlet of the reactor is not representative of the reaction to be optimized. Extrapolation on a larger scale and optimization of synthesis are then complicated, distorted or even compromised.

WO 92/07226 also describes a spiral-shaped heat exchanger comprising two helical tubes interlocked one inside the other. The tubes are placed in contact with each other to thermally exchange with a large heat exchange surface.

An object of the invention is to obtain a transformation module of at least one liquid product facilitating extrapolation on a larger scale, while offering a great versatility of use.

For this purpose, the subject of the invention is a module of the aforementioned type, characterized in that in the intermediate region, the ratio of the radius of the helix to the maximum transverse extent of the internal light is between 20 and 100, advantageously between 20 and 70.

As will be seen below, the choice of this report surprisingly leads to a marked piston character, while avoiding significantly disturbing the flow.

The module according to the invention may comprise one or more of the following characteristics, taken separately or in any technically possible combination:

Advantageously, the ratio of the pitch of the helix to the radius of the helix is less than 0.1, advantageously less than 0.08.

According to the invention, the total internal volume defined by the internal lumen in the intermediate region between the injection inlet and the recovery outlet is advantageously less than 1 liter, advantageously less than 100 milliliters, the maximum transverse extent of the traffic light in the intermediate region being especially less than 1 cm.

The combination of these characteristics makes it possible to obtain a transformation module in which the circulation of the liquid products in the tube with a view to their transformation has a character of "piston" type very marked.

This piston character is obtained by the geometric characteristics of the tube, without having mixing elements inside the tube. The residence time can also be easily adjusted while controlling the piston nature of the flow, this which helps to demonstrate concepts and extrapolate chemical reactions that are conducted in the module.

In a variant, the module may comprise a thermal regulation assembly of the product present in the first tube, the thermal regulation assembly advantageously comprising a heat transfer liquid disposed in the chamber in contact with the first tube and a means for thermal regulation of the fluid. coolant. This allows the temperature of the transformation to be precisely controlled by heating or cooling the product present in the tube.

In another embodiment, the first tube is thermally isolated, in particular by a gas, to allow the conduct of adiabatic transformations.

In the case where the thermal regulation means are absent or inactive, the module can operate in adiabatic, to increase the possibilities of exploration of the transformations of the product.

In another variant of the invention, the module comprises at least one second transformation tube, the second tube having a product injection inlet, a helical intermediate region disposed in the enclosure, and an output of product recovery, the injection inlet and the recovery outlet projecting out of the enclosure, the ratio of the radius of the helix to the maximum transverse extent of the inner lumen in the intermediate region being between 20 and 100, advantageously between 20 and 70.

The first tube and the second tube are advantageously arranged in parallel in the chamber.

The presence of a first tube and a second product conversion tube makes it possible to carry out transformations in parallel under different conditions, or to increase the residence time.

In an advantageous variant, the module comprises a connecting connection connecting the recovery outlet of the first tube to the injection inlet of the second tube, the connection fitting delimiting an internal circulation passage of the product, opening upstream in the light internal of the first tube and downstream in the internal lumen of the second tube.

In order to increase the modularity of the system and to offer increased possibilities of use, the module according to the invention can comprise the additional characteristic that it comprises an auxiliary product injection input, distinct from the product injection inlet in the first tube, the auxiliary product injection inlet being advantageously located between the recovery outlet of the first tube and the injection inlet of the second tube. This auxiliary input has the advantage of increasing the possible field of investigation of the transformations carried out using the module according to the invention, by allowing the injection of another product that can intervene at an intermediate stage of the transformation.

In another variant of the invention, the module may comprise a bypass line of a portion of the product to be transformed, the bypass pipe being stitched upstream of the intermediate region on the first tube and opening downstream of the first tube to allow a mixture between the product to be transformed and a processed product having passed through the first tube, the bypass pipe being advantageously provided with a bypass pump.

The bypass pump is adapted to circulate a selected volume fraction, between 0% and 100%, product to be transformed through the branch line. It follows from the description and the drawings that the product to be processed is the product circulating in the inlet section of the first tube upstream of the intermediate region of the first tube.

Such a bypass line allows voluntarily and masterfully degrade the character "piston" offered by the product processing tubes of the module. It is thus possible to further vary the investigation possibilities obtained using the transformation module according to the invention.

In another variant, the module comprises at least one sensor for measuring a physical and / or chemical property of the product circulating in the internal lumen, disposed downstream of the injection inlet. This makes it possible to evaluate the extent to which the transformation is taking place and to follow at which stage of the transformation of the critical phases can take place.

In another variant, the module comprises a valve calibrated at a predefined pressure, the valve being advantageously disposed in the transformation tube, downstream of the intermediate region. This valve makes it possible to significantly modify the operating parameters, especially in terms of temperature and pressure, without having to change the device to perform the tests. The preset pressure is for example slightly higher, advantageously greater than 5%, of the saturated vapor pressure of the medium flowing in the transformation tube at the temperature of this medium.

The subject of the invention is also a unit for continuously transforming at least one fluid product, characterized in that it comprises:

at least a first module as defined above; and

a product injection assembly to be converted connected to the injection inlet of the first module; In a variant, the unit comprises at least a second module as defined above distinct from the first module, at least the recovery output of a transformation tube of the first module being connected to the injection inlet of the first module. a transformation tube of the second module. This configuration makes it possible to increase the versatility of the device to obtain a device having, for example, a higher residence time.

In a variant, at least one recovery outlet of a transformation tube of the second module is connected to an injection inlet of a transformation tube of the first module.

The subject of the invention is furthermore a method for transforming a fluid product, of the type comprising the following steps:

- supply of at least one unit as defined above;

injecting at least one product to be transformed at the injection inlet of a transformation tube of the first module, and circulation of the product through the transformation tube;

- physical and / or chemical transformation of the product to be processed in the intermediate region; and

- recovery of the processed product at the recovery outlet.

The method according to the invention may comprise one or more of the following characteristics, taken alone or in any combination (s) technically possible (s):

the flow of the product in the intermediate region of the transformation tube is laminar; and

the number of perfectly stirred reactors equivalent to the intermediate region is greater than 20, and is advantageously greater than 50.

Thus, the "piston" character remains marked, even with laminar or intermediate flows having a Reynolds number of less than 10,000. This effect is all the more marked as the flow rate of injected product decreases.

The invention also relates to a module for continuous transformation of at least one liquid product, of the type comprising:

- a speaker ;

at least one first product transformation tube,

at least one second product transformation tube distinct from the first tube, the second tube being disposed in the chamber while being completely away from the first tube, the first tube and the second tube each comprising a liquid injection inlet; product, an intermediate region in the form of a helix, and a product recovery outlet transformed,

the first tube and the second tube each defining a continuous inner lumen of product flow between the injection inlet and the recovery outlet, the injection inlet and the recovery outlet projecting from the enclosure.

This module does not necessarily include the feature that in the intermediate region, the ratio of the radius of the helix to the maximum transverse extent of the inner lumen is between 20 and 100, preferably between 20 and 70.

It may include one or more of the features set out above, in isolation or in any technically feasible combination.

The invention will be better understood on reading the description which follows, given solely by way of example, and with reference to the appended drawings, in which:

FIG. 1 is a schematic partial perspective view of a first transformation unit comprising a first transformation module according to the invention;

- Figure 2 is a sectional view along a median axial plane of Figure 1;

- Figure 3 is a top view of the transformation tube of the module shown in Figure 2;

FIG. 4 is an end view of the tube of FIG. 3;

- Figure 5 is a schematic view of the connection of the first unit;

- Figure 6 is a view similar to Figure 5 for a second unit;

FIG. 7 is a view similar to FIG. 5 for a third unit according to the invention;

- Figure 8 is a view similar to Figure 7 for a fourth unit according to the invention;

FIG. 9 is a graph representing the distribution of the residence times observed at the output of a module according to the invention, after injection of an input product step; and

FIG. 10 is a graph showing the number of perfectly stirred reactors which is equivalent to a transformation tube of a module according to the invention, as well as the average residence times, as a function of the flow rate.

In what follows, the terms "upstream" and "downstream" refer to the normal direction of circulation of a fluid.

A first transformation unit 10 according to the invention is shown in FIGS. 1 to 5. This unit 10 is intended to transform at least one product introduced into the unit in the form of a fluid, such as a homogeneous or heterogeneous liquid, a liquid-liquid dispersion, gas-liquid, liquid-solid, gas-solid or a supercritical fluid.

This transformation is for example a physical transformation and / or a chemical transformation.

The transformation is for example a conventional chemical reaction using, for example, the pooling of electrons, interactions or physical repulsions, such as hydrogen bonds, electrostatic interactions, steric attractions or repulsions, affinities for different media. hydrophilic and / or hydrophobic, formulation stability, flocculation, or phase transfers, for example liquid / liquid, solid / liquid, or gas / liquid, gas / liquid / solid or solid gas.

Unit 10 is particularly suitable for studying the heterogeneous catalysis of a reaction in which the catalyst is arranged in the form of a fixed bed while being immobilized between grids or filters or is mobile with the fluid to be converted ( "Slurry") or is deposited on the walls of the tube ("washcoat").

The transformation unit 10 is advantageously a laboratory unit intended to test the transformation in order to optimize at least one parameter of the transformation and to extrapolate the transformation on a larger scale.

By "laboratory unit" is advantageously meant a unit capable of treating a flow rate of product to be processed of less than 10 l / h.

As illustrated in FIG. 1, the transformation unit 10 comprises at least one transformation module 12, and preferably at least one injection assembly 14A, 14B of a product to be transformed, and at least one assembly 16A, 16B recovery of the processed product.

In this example, the unit 10 further comprises an assembly 18 for regulating the temperature in the transformation module 12 and advantageously measuring sensors 20A, 20B. As illustrated by FIGS. 1, 2 and 5, the transformation module 12 comprises an enclosure 22 containing a coolant 24 and at least one helical tube 26A, 26B of transformation, the tube 26A, 26B being immersed in the coolant 24 of the enclosure 22.

In the example shown in Figure 2, the transformation module 12 further comprises optionally a heat insulating jacket 28 surrounding the enclosure 22 and a support 30 for carrying the enclosure 22 and the mantle 28, when present.

In the example shown in the figures, the enclosure 22 is formed by a peripheral wall 32 having a substantially horizontal axis AA ', closed off by transverse walls 34 that can be dismantled to allow access to the interior volume 36 delimited inside the enclosure. enclosure 22.

The peripheral wall 32 is substantially cylindrical.

The chamber 22 includes a heat transfer fluid injection inlet 24 in the interior volume 36, and an outlet 40 for ejecting the fluid. The inlet 38 and the outlet 40 are advantageously formed transversely in the peripheral wall 32 at an angle of 90 ° with respect to the axis A-A '.

When the end walls 34 are mounted on the peripheral wall 32, the internal volume 36 is closed in a sealed manner, with the exception of the heat transfer fluid injection inlet 38 and the fluid ejection outlet 40 coolant.

In this example, the coolant 24 is a liquid, for example water or oil. It substantially completely fills the interior volume 36.

The module 12 shown in FIGS. 1 to 5 comprises a plurality of helical tubes 26A, 26B received in the same enclosure 22.

Advantageously, the module 12 comprises two tubes 26A, 26B arranged in parallel in the enclosure 22.

In this example, the tubes 26A, 26B are arranged horizontally in the chamber 22. They thus extend respectively along horizontal axes B-B 'parallel to the axis A-A'. The tubes 26A, 26B are arranged completely apart from each other.

Alternatively, at least one tube 26A, 26B extends along an axis B-B 'vertical or inclined at a non-zero angle of less than 90 ° with respect to a vertical axis. Advantageously, the two tubes 26A, 26B extend along parallel axes B-B ', vertical or inclined.

As illustrated in FIG. 2, each tube 26A, 26B comprises an inlet section 42A, 42B, an intermediate region 44A, 44B in the form of a helix, and an outlet section 46A, 46B. The inlet section 42A, 42B protrudes out of the enclosure 22 through a first end wall 34. It advantageously extends linearly along the axis B-B 'or parallel to the axis Β- Β. It has an input connector 48 at its upstream end.

The outlet section 46A, 46B also projects through a second end wall 34 opposite to the first end wall 34. It extends linearly along the axis B-B 'or parallel to this axis. It has an output connector 50.

The intermediate section 44A, 44B is wound along a helix axis B-B '. The intermediate section 44A, 44B thus has a plurality of substantially contiguous turns 50, of circular contour, centered on the axis B-B '.

The transformation tube 26A, 26B internally delimits a continuous lumen 51 for circulating the product to be transformed extending between a product injection inlet 52A, 52B to be converted at the free end of the inlet section 42A, 42B, and a processed product recovery port 54A, 54B located at the free end of the output section 46A, 46B.

The tube 26A, 26B is advantageously made in one piece of a heat-conducting material such as a metal, having a high resistance to pressure and temperature.

The tube 26A, 26B is for example made of alloy based on molybdenum, chromium, cobalt, iron, copper, manganese, titanium, zirconium, aluminum, carbon and tungsten sold under the trademarks HASTELLOY® or a nickel alloy, chromium, iron, manganese comprising copper and molybdenum sold under the name INCONEL® and more particularly alloys HASTELLOY C276 or INCONEL 600, 625 or 718.

Alternatively, the tube 26A, 26B is made of stainless steel, for example austenitic steel as described in Robert H Perry et al., Perry's Chemical Eng- itieers Handbook, 6th Edition, 1984 (pp.23 to 44). . In particular, type 304, 304L, 316 or 316L stainless steels can be used.

Alternatively, the tube 26A, 26B is made of glass or polymer, especially polytetrafluoroethylene or Teflon®. In this case, the tube may be transparent to visible light, UV or infrared, which allows to conduct photochemical reactions. It also makes it possible to visualize the transformation, to carry out spectroscopic analysis, to use alternative energies such as microwaves, ultrasounds.

In another variant, the tube 26A, 26B is made of ceramic. In the example shown in FIG. 1, the tube 26A, 26B is adapted to allow a direct and non-contact heat exchange between the heat transfer fluid 24 present in the internal volume 36 and the product to be transformed circulating in the lumen 51.

According to the invention, the tube 26A, 26B is configured so that the flow of a laminar fluid through the lumen 51 has a character of "piston" type which will be described in detail below.

For this purpose, with reference to FIG. 4, the ratio pi of the radius R _h of the helix generated by the intermediate portion 44A, 44B of the tube 26A, 26B, to the maximum transverse extent of the internal lumen 44, corresponding to its internal diameter d ,, is less than 100, advantageously less than 70, and especially between 20 and 100 or between 20 and 70.

This ratio pi is preferably greater than 20. It is for example between 30 and 40, or between 65 and 75.

The radius R _h of the helix is greater than 10 mm, and is advantageously less than 100 mm, in particular between 30 mm and 60 mm.

The internal diameter di is generally less than 10 mm and is advantageously greater than 0.1 mm, to be between 0.5 mm and 4 mm, advantageously between 1 mm and 3 mm.

The ratio p ₂ of the pitch P of the helix generated by the intermediate section 44A, 44B on the radius R _h of the helix is also less than 0.1 and is advantageously greater than 0.01.

This ratio p ₂ is advantageously less than 0.08 and is in particular between 0.02 and 0.08. This ratio is in particular between 0.05 and 0.07 and between 0.02 and 0.04.

The internal volume V _tota i defined by the light 51, taken between the inlet 52A, 52B and the outlet 54A, 54B, is less than one liter, preferably less than 100 ml and especially greater than 1 ml.

This volume is in particular between 2 ml and 70 ml, and especially between 2 ml and 20 ml, and between 40 ml and 60 ml.

The total length L of the tube 26A, 26B, taken linearly along the tube 26A, 26B is advantageously greater than 1 meter and is in particular less than 200 meters, advantageously 50 meters.

This length is for example between 2 meters and 20 meters and in particular between 2 meters and 5 meters and between 6 meters and 12 meters.

The number of turns N _s depends on the total length of the tube 26A, 26B. It is thus greater than 1, advantageously greater than 10. When present, the heat-insulating jacket 28 substantially envelops the entire external surface of the enclosure 22, with the exception of the injection inlet 38 and the ejection outlet 40.

The support 30 is disposed under the enclosure 22.

Each injection assembly 14A, 14B comprises at least one reservoir 60 of product to be converted, and at least one pump 62 connected upstream to the reservoir 60 and downstream to the injection inlet 52A, 52B. If several products to be transformed are injected simultaneously, the assembly 14A, 14B comprises a mixer disposed upstream of the inlet 52A, 52B and downstream of the or each pump 62.

The pump 62 is able to take the product to be transformed in the tank 60 and to bring it to the light 51 to circulate it in the light 51 to the outlet 54A, 54B, at an adjustable flow rate.

Each recovery assembly 16A, 16B has a recovery receptacle 64.

The regulating assembly 18 is connected to the coolant injection inlet 38 and to the heat transfer fluid ejection outlet 40 for circulating the heat transfer fluid 24 at a chosen temperature through the interior volume 36. current of the fluid to be transformed circulating in the tubes 26A, 26B.

When the coolant 24 must be heated, the regulation assembly 18 advantageously comprises means for heating the coolant 24.

The sensors 20A, 20B when present, comprise for example a sensor 64 for measuring the temperature of the product to be transformed, a sensor 68 for detecting the amount of product transformed. They may comprise, in a variant, a sensor for measuring the pressure drop.

The temperature sensor 64 is for example stitched on the input section 42A,

42B outside the enclosure 22. The detection sensor 68 is for example stitched on the output section 46A, 46B outside the chamber 22.

In the example shown in FIG. 1, the transformation unit 10 comprises a single transformation module 12 comprising two parallel transformation tubes 26A and 26B. Each tube 26A, 26B is connected to a separate injection assembly 14A, 14B and a respective recovery assembly 16A, 16B.

For the implementation of a transformation method according to the invention, the pump 62 of each injection assembly 14A, 14B is activated to circulate product intended to be transformed from the tank 60 to an inlet 52A, 52B respectively. The product then flows into the inlet section 42A and 42B and enters the enclosure 22 to flow successively in the intermediate section 44A, 44B, then leaves the chamber 22 in the output section 46A, 46B.

In a first mode of operation, the temperature of the heat transfer fluid is regulated at a given transformation temperature, through the regulation assembly 18. The transformed product is then extracted through the outlet 50 and recovered in the receptacle 64 .

The product circulating in the lumen 51 advantageously forms a laminar or intermediate flow characterized by a Re Reynolds number of less than 10,000.

Despite this laminar or intermediate flow, and taut account of the particular dimensions of the helical tube 26A, 26B, it is possible to obtain a hydrodynamic effect of the "piston" type of variable and controllable nature. For this purpose, the number J of perfectly stirred reactors (RPA) equivalent to each tube 26A, 26B is greater than 20, and is especially greater than 50. This result is advantageously obtained for flow rates of between 0.1 ml / minute and 50 ml / minute.

Very advantageously, the number J and thus the "piston" character of the flow of the product increases when the product flow rate decreases. This also allows to significantly reduce the dead volumes.

The flow rate of the pumps 60 is advantageously adjusted to obtain a residence time in each tube 26A, 26B between 5 seconds and 4 hours.

The pressure drop across each tube 26A, 26B is quite low and conventionally depends on the viscosity and the rheology of the fluid passing through the tube 26A, 26B, and is for example between 20 millibars and 2 bars, for water at room temperature at different flow rates.

The number J of perfectly stirred reactors equivalents and time _t z crossing stirred tank reactor are calculated by estimating a balance on each equivalent reactor of rank i by the equation:

C (i - 1, t) = C (i, t) + T.dC (i, t) / dt

where C (i, t) is the color indicator concentration in reactor i at time t. The concentration C (input, t) of a colored indicator injected by the assembly 14A,

14B is measured as a function of time t at a given frequency over a chosen time interval, of the order of 1 to 10 times the passage time in the tube.

The concentration C (output, t) of the color indicator recovered at the output 54A, 54B as a function of time is measured over the time interval chosen at the same frequency. Then, the parameter J and the parameter τ, are adjusted by propagating the signal

C (input, t) in all the elementary reactors until the calculated concentration C (J, t) is as close as possible to C (output, t) over the set of measurement times in the range of chosen time, using a mathematical convergence method, for example by least squares regression.

It is observed that the difference between the model and the experimental results is even lower than the internal diameter of the tube 26A, 26B is low and the speed is low.

The unit 10 shown in FIG. 1 makes it possible to test several parallel flow operating conditions, for example by adjusting the flow rate of the pumps 62 of each injection assembly 14A, 14B, using the same starting material in the sets. injection 14A, 14B, or by changing the length of the tubes 26A, 26B or unlike the separate starting materials in each set 14A, 14B.

The presence of two tubes 26A, 26B arranged in parallel allows a great versatility of use of the modules 12.

Thus, FIG. 6 illustrates a second processing unit 80 according to the invention. Unlike the first unit 10, the inlet pipe 42B of the second pipe 26B is located on the same side as the outlet pipe 46A of the first pipe 26A.

The second unit 80 further comprises a connection fitting 82 connecting the output 54A of the first tube 26A to the input 52B of the second tube 26B. The connector 82 has an input connector 84 mounted on the output connector 50 of the first tube 26A and an output connector 86 mounted on the input connector 48 of the second tube 26B.

The connector 82 has a connecting lumen 88 opening, upstream, in the inner lumen 51 of the first tube 26A, and downstream in the inner lumen 51 of the second tube 26B.

Thus, a continuous fluid path is established between the injection assembly 14A, the inner lumen 51 of the first tube 26A, the connecting lumen 88 and the inner lumen 51 of the second tube 26B.

This arrangement increases the residence time of the product to be transformed in the chamber 22.

In a variant, the second unit 80 further comprises an auxiliary injection assembly 90 of an auxiliary product. The auxiliary assembly 90 comprises a reservoir 92 of liquid auxiliary product and a pump 94, whose output is connected to a stitching point 96 opening into the connector 82. The auxiliary product is advantageously liquid. It is thus possible to perform a first transformation through the tube 26A with the aid of the starting product, and then to add an auxiliary product in the partially converted product at the outlet of the first tube 26A. The mixture formed by the auxiliary product and the partially converted product is then injected into the second tube 26B to form the processed product at the outlet of the second tube 26B.

A third transformation unit 100 according to the invention is shown in FIG. 7. Unlike the second unit 80, the third unit 100 comprises a bypass tap 102 connecting the inlet section 42A of the first tube 26A to the section output of the second tube 26B.

The bypass tap 102 is provided with a pump 104 with an adjustable flow rate. It is thus possible to derive a volume fraction of between 0% and 100% of the product to be converted directly into the outlet section 26B, without passing through the chamber 22. Such a configuration makes it possible to deliberately degrade the "piston" character of the transformation module 12. This makes it possible, for example, to determine what is the "piston" requirement of a given chemistry. As a result, it is possible to size the pilot or industrial reactor to just the necessary from a hydrodynamic point of view to minimize investment and proportional costs while ensuring high chemical performance.

A fourth unit 1 10 according to the invention is shown in Figure 8. Unlike the first unit 10, the fourth unit 1 10 comprises a plurality of modules 12C, 12D connected in series.

As a variant, this number may be greater than 2. In this example, the number of modules 12C, 12D is equal to 2.

The output section 46A of the first tube 26A of the first module 12C is connected to the input section 42A of the first tube 26A of the second module 12D. Similarly, the output section 46B of the second tube 26B of the second module 12D is connected to the input section 42B of the second tube 26B of the first module 12C.

The second module 12D is provided with a connection 82 connecting the first tube 26A to the second tube 26B, of structure similar to that described above for the second unit 80. Thus, the connector 82 hydraulically connects the outlet section 46A of the first tube 26A of the second module 12D and the input section 42B of the second tube 26C of the second module 12D.

Thus, a continuous fluidic path can be established for the product to be transformed between the injection assembly 14A, the first tube 26A of the first module 12C, the first tube 26A of the second module 12D, the connection fitting 82, the second tube 26B of second module 12D, the second tube 26B of the first module 12C and the recovery assembly 16A.

The residence time of the product to be transformed in the successive enclosures 22 is thus increased. Moreover, it is possible to subject various heat treatments to the product to be processed, for example by subjecting it to different temperatures in the successive enclosures 22.

In a variant, the fourth unit 1 10 comprises a plurality of auxiliary injection assemblies 90 as described above, stitched respectively on the connection fitting 82 and / or on one of the connection tubes between the modules 12C, 12D respectively formed by the outlet pipe 46A of the first tube 26A of the first module 12C associated with the inlet pipe 42A of the first tube 26A of the second module 12C or formed by the outlet pipe 46B of the second pipe 26B of the associated second module 12D to the inlet pipe 42B of the second tube 26B of the first module 12C.

It is therefore possible to vary substantially the operating conditions, by adjusting the respective temperatures of the speakers 22, and the nature and flow rate of auxiliary products added by the auxiliary injection sets 90. In addition, temperature sensors 66 and detection 68 may be placed at various points on the connecting pipes or on the connection 82 to accurately study the conditions of the transformation.

The "piston" character of each tube 26A, 26B of each module 12 is illustrated by the distribution of the residence time as a function of time shown in FIG. 9, for a color indicator injected at the input in the form of a concentration step. .

The number of perfectly stirred reactors equivalent for different flow rates and the average residence time τ in each reactor are shown as a function of the flow rate in FIG. 10. As can be seen in these figures, the dispersion is minimal as a result of injection at the input of a product step. This dispersion is much lower than that observed for a linear tube of similar length.

The number of equivalent reactors is at least greater than 20, or even greater than

100 when the flow decreases.

In a variant of the first unit 10, the second unit 80, the third unit 100, and the fourth unit 1 10, the transformations are performed adiabatically.

In this case, the tubes 26A, 26B are not necessarily immersed in a liquid but can be placed in a volume of gas.

Thus, each transformation tube 26A, 26B is for example immersed in a fluid capable of being a thermal insulator with respect to the tube 26A, 26B. This fluid is for example a gas such as ambient air.

In this case, the unit 10 is devoid of means for regulating the temperature in each tube 26A, 26B.

During the implementation of the process according to the invention, the product to be transformed circulating in each tube 26A, 26B evolves adiabatically, without heating or external cooling.

In this case, the enclosure 22 is advantageously covered with the heat-insulating jacket 28 described above.

In another variant, the regulation assembly 18 includes means for heating the tube 26A, 26B without any heat transfer liquid 24.

For this purpose, the thermal regulation assembly remains clean to heat the product present in the tube 26A, 26B over the entire periphery of the tube 26A, 26B.

These heating means are, for example, in-mass heating means such as a microwave source, or means for heating the tube, such as induction heating means, hot air heating means, means for heating, infra-red heating or other heating means.

In a variant, the thermal regulation assembly further comprises cooling means.

In another variant, the number of tubes 26A, 26B in the chamber is greater than 2.

In yet another variant, a valve calibrated at a predefined pressure advantageously greater than the atmospheric pressure is placed at the outlet of a helical tube. The preset pressure is for example chosen to be slightly higher, for example at least 5% higher than the saturated vapor pressure of the reaction medium circulating in the tube at the reaction temperature to which the reaction medium is subjected.

This allows to significantly vary in particular the transformation temperature that can be tested in a module according to the invention, without having to change units to test these variations, especially when certain compounds are likely to boil at the temperature tested. Thus, it is possible to determine very easily and quickly whether modified operating conditions make it possible to increase the selectivity and / or the conversion.

The dimensions of the circulating light, and in particular the small diameter of the helical tube, guarantee a S / V ratio between the internal surface S delimited by the tube and the volume V of the circulation light between 400 m ^-1. and 4000 m ^-1 , advantageously between 500 m ^-1 and 3000 m ^-1 . This is favorable to a good heat exchange through the tube. In addition, this makes it possible to demonstrate a possible catalysis of the wall, especially when the tube is made of a metallic material. This catalysis of the wall can be demonstrated in a much simpler way than in a conventional stirred reactor, and without disturbing the hydrodynamics of the reaction medium, or introducing a dispersed material or an insert into the reaction medium. .

As indicated in the description above, with reference to the accompanying figures, the fact that the turns 50 are substantially contiguous means that each turn 50 is in contact with an adjacent turn 50 on at least a portion of its outer surface.

Claims

1. Module (12) for continuous transformation of at least one fluid product, of the type comprising:

an enclosure (22);

at least one first product transformation tube (26A), the first tube

(26A) comprising a product injection inlet (52A), a helical intermediate region (44A) disposed in the enclosure, and a product recovery outlet (54A), the first tube (26A) defining an internal lumen (51) continuous circulation of the product between the injection inlet (52A) and the recovery outlet (54A), the injection inlet (52A) and the recovery outlet (54A) protruding outside the enclosure (22);

characterized in that, in the intermediate region (44A), the ratio of the radius (R _h ) of the helix to the maximum transverse extent (di) of the inner lumen (51) is between 20 and 100, advantageously between 20 and 70.

2. Module (12) according to any one of the preceding claims, characterized in that the ratio of pitch (P) of the helix on the radius (R _h ) of the helix is less than 0.1, advantageously less than 0.08.

3. - Module (12) according to any one of the preceding claims, characterized in that the total internal volume defined by the inner lumen (51) in the intermediate region between the injection inlet (52A) and the outlet of recovery (54A) is less than 1 liter, preferably less than 100 milliliters, the maximum transverse extent (di) of the circulation light (51) in the intermediate region (44A) being in particular less than 1 cm.

4. - Module (12) according to any one of the preceding claims, characterized in that it comprises a set (18) of thermal regulation of the product present in the first tube (26A), the assembly (18) of regulation thermal comprising advantageously a coolant liquid (24) disposed in the enclosure (22) in contact with the first tube (26A) and a thermal control means of the coolant (24).

5. - Module (12) according to any one of claims 1 to 3, characterized in that the first tube (26A) is thermally isolated, in particular by a gas to allow the conduct of adiabatic transformations.

6. - Module (12) according to any one of the preceding claims, characterized in that it comprises at least a second tube (26B) of transformation, the second tube (26B) having an inlet (52B) for injection of product, a helical intermediate region (44B) disposed in the enclosure and a product recovery outlet (54B), the injection inlet (52B) and the recovery outlet (54B) projecting from the enclosure (22), the ratio of the radius (R _h ) of the helix to the maximum transverse extent of the internal lumen (51) in the intermediate region (44B) of between 20 and 100, advantageously between 20 and 70.

7. Module (12) according to claim 6, characterized in that it comprises a connecting connection (82) connecting the recovery outlet (54A) of the first tube (26A) to the injection inlet (52B) of the second tube (26B), the connection fitting (82) delimiting an internal product circulation passage opening, upstream, into the internal lumen (51) of the first tube (26A) and downstream into the internal lumen (51). ) of the second tube (26B).

8. Module (12) according to claim 7, characterized in that it comprises an auxiliary input (90) of product injection, distinct from the inlet (52A) of product injection in the first tube (26A ), the auxiliary product injection inlet (90) being advantageously located between the recovery outlet of the first tube (26A) and the injection inlet of the second tube (26B).

9. Module (12) according to any one of the preceding claims, characterized in that it comprises a bypass line (102) of a portion of the product to be transformed, the bypass line (102) being quilted upstream of the intermediate region (44A) on the first tube (26A), and opening downstream of the first tube (26A) to allow mixing between the product to be transformed and a transformed product having passed through the first tube (26A), the pipe bypass (102) being advantageously provided with a bypass pump.

10. - Unit (10; 80; 100; 1 10) of continuous transformation of at least one fluid product, characterized in that it comprises:

at least one first module (12; 12C) according to any one of the preceding claims;

- a product injection assembly (14A, 14B) to be transformed connected to the injection inlet (52A) of the first module (12; 12C).

1 1. - Unit (1 10) according to claim 10, characterized in that it comprises at least one second module (12D) according to any one of claims 1 to 9, distinct from the first module (12C), at least the output of recovering (54A) a transformation tube (26A) of the first module (12C) being connected to the injection inlet (52A) of a transformation tube (26A) of the second module (12D).

12. - Unit (1 10) according to claim 1 1, characterized in that at least one recovery outlet (54B) of a transformation tube (26B) of the second module (12D) is connected to an input of injection (52B) of a transformation tube (26B) of the first module (12C).

13. - Process for converting a fluid product, of the type comprising the following steps:

providing at least one unit (10; 80; 100; 1 10) according to any one of claims 10 to 12;

injecting at least one product to be transformed at the injection inlet (52A) of a transformation tube (24A) of the first module (12; 12C), and circulation of the product through the transformation tube (24A); );

- Physical and / or chemical transformation of the product to be transformed in the intermediate region (44A);

- recovery of the processed product at the recovery outlet (54A).

14. - Method according to claim 13, characterized in that the flow of the product in the intermediate region (44A) of the transformation tube (24A) is laminar or intermediate.

15. - Process according to claim 14, characterized in that the number of perfectly stirred reactors equivalent to the intermediate region (44A) is greater than 20, and is advantageously greater than 50.