Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
  • G01K17/00—Measuring quantity of heat
  • G01K17/006—Microcalorimeters, e.g. using silicon microstructures
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J19/0093—Microreactors, e.g. miniaturised or microfabricated reactors
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N25/00—Investigating or analyzing materials by the use of thermal means
  • G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
  • G01N25/48—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation
  • G01N25/4873—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation for a flowing, e.g. gas sample
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00781—Aspects relating to microreactors
  • B01J2219/00788—Three-dimensional assemblies, i.e. the reactor comprising a form other than a stack of plates
  • B01J2219/00792—One or more tube-shaped elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00781—Aspects relating to microreactors
  • B01J2219/00819—Materials of construction
  • B01J2219/00833—Plastic
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00781—Aspects relating to microreactors
  • B01J2219/00891—Feeding or evacuation
  • B01J2219/00903—Segmented flow
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00781—Aspects relating to microreactors
  • B01J2219/0095—Control aspects
  • B01J2219/00952—Sensing operations
  • B01J2219/00954—Measured properties
  • B01J2219/00961—Temperature
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00781—Aspects relating to microreactors
  • B01J2219/0095—Control aspects
  • B01J2219/00952—Sensing operations
  • B01J2219/00968—Type of sensors
  • B01J2219/0097—Optical sensors
  • B01J2219/00977—Infrared light
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00781—Aspects relating to microreactors
  • B01J2219/0095—Control aspects
  • B01J2219/00984—Residence time

Definitions

• the present invention relates to a method for determining at least one parameter of a physical and / or chemical transformation, a device for implementing this method, and an installation comprising at least one such device.
• transformation is meant any type of interaction likely to occur in a mixture of at least two components.
• this transformation can be a reaction of chemical and / or physical type, such as for example any type of conventional chemical reaction, as well as crystallization or precipitation, or, inter alia, modification of a liquid equilibrium. /steam.
• such a transformation is capable of implementing chemical phenomena, by exchange or sharing of electrons, physical interactions or repulsions, such as hydrogen bonds, electrostatic interactions, steric attractions or repulsions, affinities for different hydrophilic and / or hydrophobic media, formulation stabilities, flocculations or even phase transfers, for example of the liquid / liquid, solid / liquid or gas / liquid type.
• a system capable of undergoing such a transformation is called a physicochemical system.
• the parameters of such a transformation are, in particular, of a thermodynamic nature. In this context, it is particularly the enthalpy specific to this transformation. However, these parameters may also be, without limitation, kinetics of chemical reaction in a homogeneous or heterogeneous medium, or conditions for obtaining an optimum yield for chemical reactions.
• the invention also makes it possible to study energy-type transformations, such as viscous dissipations for which the flow of a high-viscosity product leads to the formation of heat.
• thermodynamic and kinetic parameters of a transformation is of significant interest in the development and safety of chemical processes. Two major phenomena are present in such a transformation, namely heat transfer and kinetics, which can be studied through calorimetry.
• the reagents are admitted into the aforementioned chamber and, after having mixed the latter, the temperature of the auxiliary liquid flowing in the double wall is varied. The evolution of the temperature difference between this liquid and the internal volume of the reaction chamber is then measured so as to determine the corresponding reaction enthalpy.
• microcalorimethe which are for example described in “I. Wads ⁇ , Thermochim. Acta, 294, pp 1-11, 1997. "
• This solution is concerned with very small variations in temperature, while involving relatively large reaction volumes. It is operated in a closed reaction medium, at constant volume.
• FR-A-2,004,343 discloses a method for determining at least one parameter of a chemical reaction, wherein the reactants flow in a channel. The overall heat flux associated with the reaction is then measured via a thermopile.
• This last known solution is however not proving completely satisfactory, insofar as it only allows access to surface information, namely of the global type and not local. Under these conditions, the installation described in this document does not allow to deduce, easily, a large number of parameters. That being said, the invention aims to remedy the various disadvantages of the prior art mentioned above.
• the object of the invention is therefore to propose a method which makes it possible to reliably determine at least one parameter, in particular thermodynamic, of a transformation and which can be implemented economically, by using relatively small quantities of products that are susceptible to undergo this transformation. It also aims to propose such a method that makes it possible to vary in a fast and convenient manner the driving parameters of this transformation, in particular the concentration, the flow rate and the residence time of the aforementioned products. Finally, the invention aims to propose such a method, which makes it possible to access a large number of data concerning the transformation studied, as well as to local type information relating to this transformation.
• a physicochemical system suitable for undergoing said transformation, is made to flow in a flow member, while maintaining at the same temperature the outer periphery of the wall of this flow member, with the exception of a viewing zone, at least between two axially distant points of this flow member, respectively called upstream and downstream;
• At least one spatial distribution of the temperature of the physico-chemical system is visualized along this viewing zone, between these two upstream and downstream points, at least one instant; - We deduce the or each parameter, from the or each spatial temperature distribution.
• the flow member has a thermally insulating wall, and a zone of contact of this wall is maintained at the same temperature by putting it in contact with a solid, thermally conductive member, whereas the viewing area with this massive organ; the points respectively upstream and downstream of the flow member correspond to the inlet and the outlet of the contact zone of this flow member, with the thermally conductive member;
• the flow member is a tubular member that can be removably attached to the thermally conductive member; the one or each spatial distribution of the temperature is visualized by means of an infrared camera;
• the value of this heat exchange coefficient is determined by flowing a fluid equivalent to the physicochemical system, not undergoing transformation, inside the flow member; the value of the heat exchange coefficient is determined from the value of the sensitivity coefficient of a camera, this camera making it possible to obtain the spatial distribution of temperature along the viewing zone;
• the sensitivity coefficient is determined by introducing a reference fluid into the flow member, supplying the reference fluid with different electrical power values, and measuring the corresponding temperature rise at the viewing zone; ;
• the physicochemical system is made to flow at different molar flow rates, and at least one spatial temperature distribution is visualized for each of these flow rates and / or at least one distribution is deduced; space of the local heat flux and / or deducing at least one value of the global heat flux;
• the variation of the global heat flux is determined as a function of the molar flow rate, and an enthalpy value of the transformation is derived therefrom;
• the internal section of the flow member is between 100 ⁇ m 2 and 25 mm 2 , in particular between 10,000 ⁇ m 2 and 1 mm 2 ;
• the molar flow rate of the physico-chemical system in the flow member is between 100 pmol / s (picomole per second) and 1 mmol / s, preferably between 1 nmol / s (nanomole per second) and 100 nmol / s; the volume of the physicochemical system in the flow member is between 1 and 10 ⁇ l per centimeter of said flow member;
• the dimensions of the flow member and / or the flow rate and / or the molar flow rate of said physicochemical system are adjusted so that said transformation is completed at the downstream point of the flow member;
• the physicochemical system is a mixture of at least two components and this mixture is made to flow in the form of drops, separated by sections of a carrier fluid, into the flow member;
• the physico-chemical system is a mixture of two components and these two components are flowed in parallel, in the flow member; at least one off-line analysis of the physicochemical system is carried out downstream of the downstream point of the flow member, in particular in a chromatograph;
• the transformation is stopped, in particular by means of quenching, then the analysis is performed offline.
• the invention also relates to an installation for implementing the above method, comprising:
• the flow member is tubular
• the tubular member is thermally insulating, in particular made of a polymer material, in particular of PTFE;
• the means for imposing a set temperature comprises a solid thermally conductive member, which is hollowed a groove for receiving the tubular flow member;
• the thermally conductive member is associated with means for changing its temperature, including a thermostated base; the flow member is etched in walls of the thermally conductive member;
• the display means comprise an infrared camera
• the supply means comprise plug generation means intended to form the physico-chemical system, separated by carrier phase sections;
• the determination means comprise computer processing means.
• FIG. 1 is a front view, schematically illustrating an installation according to the invention, for determining at least one parameter of a transformation
• FIG. 2 is a view from above, explodingly illustrating some of the elements constituting the installation of FIG. 1;
• FIGS. 3 and 4 are front views, illustrating means for generating plugs belonging to FIG. installation according to the invention:
• - Figure 5 is a top view, illustrating a type of flow likely to occur in the installation according to the invention, which is different from the flow illustrated in Figure 4;
• FIG. 6 is a cross-sectional view, illustrating more precisely the temperature profile at the outer surface of a flow member belonging to the installation of the preceding figures;
• FIG. 7 is a view from above, illustrating this temperature profile along this flow member
• FIG. 8 is a cross-sectional view, similar to Figure 6, illustrating an alternative embodiment of the flow member
• FIG. 9 is a graph illustrating the implementation of a first phase of the method according to the invention.
• FIG. 10 is a graph, grouping different curves illustrating the variation of temperature as a function of distance, for different flow rates, during this second phase;
• FIG. 11 is a graph illustrating the determination of an exchange coefficient during this second phase
• FIG. 12 is a graph, similar to FIG. 10, illustrating different temperature variations as a function of distance, for several flow rates, obtained during a third phase of the method of the invention
• FIG. 13 is a graph illustrating the variation of the local thermal flux as a function of distance for the different flow rates of FIG. 12;
• FIG. 14 is a graph illustrating the variation of the global heat flux as a function of the molar flow rate, during the implementation of this third phase.
• FIGS. 15 to 17 are graphs, similar to FIG. 13, illustrating the variation of local thermal flux as a function of distance, for different types of reaction.
• the installation according to the invention firstly comprises a block 2, made of a high capacitance material, such as bronze, or aluminum.
• This block rests on a base 4, which is thermostated by any appropriate means.
• a base 4 which is thermostated by any appropriate means.
• This block 2 is further hollowed with a groove 6 for receiving a tubular member 8, called flow member.
• the latter has walls that are made of a thermally insulating material, such as PTFE or glass.
• this tubular member 8 has for example a polygonal shape, including square as in Figure 1. However, it is also possible to provide other profiles, such as in particular a circular cross section.
• this inner section is typically between 100 ⁇ m 2 (for example 10 ⁇ m by 10 ⁇ m) and 25 mm 2 (for example 5 mm by 5 mm).
• this section is, for example, between 10,000 ⁇ m 2 (in particular 100 ⁇ m by 100 ⁇ m) and 1 mm 2 (in particular 1 mm by 1 mm).
• this size range causes a substantially laminar flow within this tube 8, with a very low Reynolds number.
• the tubular member 8 may be flexible, which is advantageous because it is then likely to be housed, simply, in the receiving groove 6. However, it is also possible to provide a rigid tubular member, for example made of glass .
• this tubular member 8 is "isolated", namely that it can be removably attached in the groove 6.
• this tubular member 8 can be arranged in the walls of the block 2 a channel of flow, according to the conventional procedures of the state of the art. After the initial etching phase, it is a question of producing the peripheral walls of this channel in an insulating material, by any appropriate means.
• the tubular member 8 has corrugations, which allows to increase the length for a given block surface.
• the installation according to the invention further comprises an infrared camera 10 (or IR camera), of conventional type, which is directed towards the organ
• This camera is capable of filming the assembly of the tubular member 8 between its inlet E and its outlet S, which correspond to the point of contact of this tubular member with the opposite edges of the solid block.
• This IR camera is associated with a processing computer 11, of any appropriate type. In the example illustrated, the use of an infrared camera has been described.
• any other type of camera coupled with modulated laser excitations, may also be used, which is capable of measuring a temperature field.
• This camera uses thermoreflectivity or thermoreflectance methods.
• the face of the block 2, facing the camera 10, is covered with an opaque film not shown. Under these conditions, the whole of this surface, including the portion of the tubular member 8 opposite the camera, is comparable to a thermally black body.
• the tubular member 8 is associated with means for generating plugs, which are more particularly illustrated in FIGS. 3 and 4.
• These means comprise firstly a substantially cylindrical coupling member 14 made of a suitable material, especially metal or plastic.
• This coupling member comprises an internal volume V, placed in communication with the outside by three different ways.
• this member 14 is first provided with a channel 16 and a chamber 18, which are coaxial and have a cross section respectively lower and greater than that of the interior volume V.
• connecting member 14 is hollowed out of a channel 20, said upper, provided at the top of Figures 3 and 4.
• An end piece 22, made for example of PEEK, PTFE, silicone or metal, is fixed by any appropriate means on the walls of the outlet of this lateral channel 20.
• the connecting member 14 receives the opposite end, denoted 81, of the tubular member 8, as well as two capillaries 24 and 26, made for example of PEEK.
• the capillary 24 has an equivalent diameter smaller than that of the capillary 26 since, as will be detailed hereinafter, this capillary 24 enters into service in the interior volume of the capillary 26.
• this external capillary 26 has a diameter equivalent which is less than that of the organ 8.
• the capillary 24 enters the latter 26 its outside diameter is smaller than the internal diameter of the peripheral capillary 26.
• the plug generation means In order to form the plug generation means (see FIG. 4), it is first of all to drive the outer capillary 26 into the channel 16, while disposing the inner capillary 24 in the volume of this outer capillary 26
• the flow member 8 is furthermore placed in the chamber 18, until its end comes into abutment with the shoulder 18 'separating this chamber 18 from the internal volume V.
• the walls facing the flow member 8 and the capillary 26 form a covering zone, denoted R, which extends immediately downstream, namely to the right of the shoulder 18 'on FIG. 4.
• the downstream end 24 'of the inner capillary 24 is flush with the downstream end 26' of the outer capillary 26, namely that these two ends occupy the same axial position, with reference to the main axes of the capillaries 24 and 26.
• capillaries 24 and 26 receive means for injecting two fluids, of a type known per se.
• the injection means of each fluid comprise a not shown tube, of flexible type, which is associated with a syringe and a syringe pump, also not shown.
• the nozzle 22 cooperates with means for injecting a third fluid, which comprise, for example, an additional tube, also flexible, which is associated with a syringe and a syringe not shown.
• the tip 22 injects an auxiliary fluid P, which is immiscible with the mixture of two first precipitated fluids.
• the injection rate typical of these different fluids is for example between 500 ⁇ l / h and 50 ml / h.
• the ratio between, on the one hand, the flow of auxiliary fluid P and, on the other hand, the sum of the flow rates of the two fluids A and B, is for example between 0.5 and 10.
• the flow rate auxiliary fluid P is greater than the sum of those of A and B, with for example a ratio close to 2.
• the auxiliary fluid then flows into the internal volume V, more precisely into the annular space formed by the walls facing the flow member 8 and the outer capillary 26.
• the first two fluids are brought into mutual contact, in a so-called mixing zone, denoted M.
• the two reactive fluids, flowing in the respective capillaries 24 and 26, are found only at this mixing zone, and not before this zone.
• these two fluids A and B are brought into contact, in a so-called contact zone denoted by C, with the immiscible carrier fluid P.
• This zone R makes it possible to visualize the formation of the drops, which allows the user to control the manipulation. Indeed, in the absence of such a covering area, the drops would be formed within the connecting member 14, which is not necessarily transparent.
• drops G each consisting of the mixture of A and B, are formed at the contacting zone C. note that these drops G form plugs, constituting themselves a physico-chemical system within the meaning of the invention.
• each drop is formed of two components A and B, which are substantially unmixed. Then, as we move downstream, the two components are better and better mixed, while the transformation that we want to study is more and more advanced.
• each drop is formed of two components A and
• the drops have at least three components.
• FIG. 5 illustrates an alternative embodiment of the invention, which does not use plug generation means.
• the inlet of the tubular member 8 is not associated with means for creating plugs, but only with at least two upstream tubes, not shown, each of which allows the admission of a reagent in the tubular member 8.
• the outlet of these two upstream tubes in the flow member 8 is effected at the inlet E of the latter.
• the reactants which here are two in number C 1 and C 2 , flow in a substantially parallel manner, at least in the upstream portion of the tube 8, on either side of an interface I. . It is interesting to form a succession of drops, in particular when the transformation occurring between the two components is theoretically very slow.
• this measure makes it possible to accelerate the mixing of the two components, within each drop.
• This embodiment is also suitable for transformations presenting a risk of explosion, insofar as each drop forms a very small volume, which consequently makes it possible to minimize the effects of such an explosion.
• the various carrier phase segments can advance them within the tube.
• the transformation between the two components is effected solely by diffusion in the vicinity of their interface.
• this embodiment it is advantageous to use this embodiment to study theoretically very fast transformations, or interfacial type.
• the length of the flow tube, separating its inlet E and its outlet S, is typically between 1 cm and 50 cm, whereas the total flow of components flowing in this tube 8 is between 250 ⁇ l / h and 10,000 ⁇ l / h. Moreover, the total amount of these components, present in the flow tube 8, is advantageously between 1 ni (nanolitre) and 10 ⁇ l per centimeter of channel.
• the transformation occurring in the tubular member 8 produces a certain amount of heat, which can be positive or negative depending on whether this transformation is exothermic or endothermic. With reference to FIG. 6, this then induces a variation of the temperature, denoted T 1 , of the components A and B in the internal volume V of the tubular member 8.
• the outer wall of the tubular member 8 can be divided into two zones, depending on whether or not it is in contact with the solid block 2. With reference to Figure 6, since this wall forms a quadrilateral, there are three sides in contact with the solid block 2, which thus form a contact zone noted 9i. On the other hand, the fourth side of this quadrilateral, which is not in contact with the solid block 2 and which is in the field of the camera, forms a so-called viewing zone, denoted 92.
• the contact zone 9i occupies a substantial fraction of the total periphery of the outer wall of the tube 8.
• the percentage occupied by this contact zone depends closely on the shape factor of the tube.
• the length of this contact zone is advantageously greater than 75%, in particular 90%, of the total periphery of the outer wall of the tube.
• the contact zone 9i is placed at the same temperature at all points, namely along its periphery and according to its length.
• This temperature of this contact zone corresponds substantially to that of the solid block 2.
• the temperature noted T s of the viewing zone 9 2 which is not in contact with the solid block 2, is liable to vary as a function of the fluctuations of the internal temperature T 1 .
• T s of the viewing zone is variable, depending on the local heat fluxes brought by the transformation inside the tubular member.
• the IR camera 10 measures the spatial distribution of this temperature T s along the tubular member, namely what is hereinafter referred to as the "temperature field". More specifically, this camera performs a number of discrete temperature measurements, at regularly distributed points of the viewing area. The number of these points is typically between 100 and 10,000, in particular equal to 1000.
• T S (i) at T S (n) the different temperatures thus measured along the tube, for which, as seen above, n is between 100 and 10 000.
• the camera makes a large number of images for each point 1, and then averages them.
• Figure 8 illustrates an alternative embodiment of the invention, in which the tubular flow member 108 is circular.
• the groove 106 formed in the solid block 102 has the shape of a circle portion, the tube 108 being inserted into force in this groove.
• a contact zone 109i which extends over most of the outer periphery of the member 108, and a viewing zone 1092, which is not in contact with the organ massive 102.
• the measurement of the temperature field provides access to parameters, especially thermodynamic, in particular thermochemical, such as enthalpy and kinetics.
• thermodynamic in particular thermochemical
• thermochemical such as enthalpy and kinetics.
• the calibration step is intended to determine the response of the camera as a function of the heat flux, which can be released by the transformation that one wishes to study.
• the reaction medium is replaced by a heating wire, releasing an electrical flow of known value.
• this heating wire which is not shown, is introduced inside the tubular member 8.
• This wire is also supplied with current by means of a stabilized supply.
• the electrical voltage across the heating wire is measured using a suitable voltmeter.
• the actual calibration phase comprises first of all a step of filling the tubular member, by means of a so-called “equivalent” fluid, namely having thermal properties similar to those of the mixture of components that is desired. to study.
• This equivalent fluid must however be neutral, namely that it must not be transformed.
• This equivalent fluid can be formed of the same components as the physicochemical system which one wishes to study, but in concentrations much lower, so that transformation does not occur.
• This equivalent fluid may also be identical to the physicochemical system studied, yet without a component allowing the transformation to occur, such as a catalyst or a polymerization initiator. Then, the heating wire is assigned different electrical powers, which lead to gray levels (denoted DL) respectively of the camera.
• hS is the sensitivity coefficient (W / DL) specific to the camera
• T s corresponds to the temperature (in DL) of the viewing zone 92 of the tube 8, which is substantially the same along this tube, and
• T c is the set temperature (in DL) imposed by the block 2, namely that of the contact zone 9i of the outer walls of the tube 8.
• This preliminary calibration step is particularly advantageous, insofar as it makes it possible to know the behavior of the camera 10, as a function of the experimental parameters. These include the geometry of the tube, the thermal characteristics of the materials used, and the operating conditions.
• this calibration step it implements the calibration step, which aims to evaluate the thermal properties of the components suitable for undergoing the transformation, which one wishes to study.
• this calibration will make it possible to estimate the duration, or the distance of flow necessary for the temperature of the components equal to the set temperature, in the absence of any transformation.
• an "equivalent" fluid is flowed into the tube 8, as defined in the above calibration step.
• two successive calibrations of each fluid, taken in isolation can be performed in order to deduce two exchange coefficients.
• the global exchange coefficient is then calculated by a mixing law.
• the flow of the equivalent fluid in the tube 8 is carried out at a first flow di.
• the two components A and B which can induce a transformation that one wishes to study, are flown in the tube 8.
• the contact zone is made to coincide.
• the temperature field of the viewing zone 9 2 is visualized along the tube 8, namely as the transformation of the components undergoes progress.
• a and B Several displays of this temperature field are then carried out for different flow rates, again analogously to the steps implemented with the equivalent fluid.
• the two components A and B are admitted into the tube 8, at an initial temperature corresponding to the set temperature T c .
• the curves of FIG. 12 correspond only to the temperature variation caused by the physico-chemical transformation of the components.
• the next step is to determine the local heat flux values, for each of the n points of the tube 8, for which a local temperature has already been measured.
• ⁇ L (i) (T 8 (i + 1) - T 8 (i)) / (z (i + 1) - Z (i)) - H (T s (i) - T c ) where i varies from 1 to ri, the number of measurements along the tube.
• each local heat flux is made for the different flow rates.
• the variation of this flux ⁇ G is then reported as a function of the molar flow d, according to the curve illustrated in FIG.
• This variation which is substantially linear, can be minimized by an appropriate mathematical method, such as a linear regression.
• the slope of the regression line D 'then corresponds to the enthalpy of the transformation.
• an off-line analysis of the reaction mixture downstream of the tube 8 can be carried out by means of any suitable apparatus, in particular a chromatograph.
• a quenching of the mixture of components is carried out, so as to stop the progress of this transformation.
• the invention achieves the previously mentioned objectives.
• the invention makes it possible to use very small volumes of the physicochemical system that it aims to study. This is advantageous, on the one hand, for the highly exothermic reactions, to the extent that there is no risk of major explosion. On the other hand, the use of small volumes is of significant importance, in the case of a physicochemical system whose price is high.
• the invention makes it possible to access local type information relating to the transformation that one wishes to study.
• the invention makes it possible to identify other types of kinetics.
• FIG. 15 there is a bell-shaped local heat flux profile, indicative of a moderately fast transformation.
• Figure 16 there is a profile in the form of a double bell, meaning that the transformation occurs in two successive phases.
• Figure 17 we find a flow profile that grows very slowly, which is characteristic of a transformation also very slow.
• FIGS. 1 to 4 For this purpose, the installation of FIGS. 1 to 4 is used.
• the length of the tube 8, between its inlet E and its outlet S, is equal to 45 cm.
• This tube, of circular cross section, has an inside diameter of 1.60 mm and an outside diameter of 3.20 mm.
• PTFE has a thickness of 0.80 mm.
• the block 2 which has a thickness of 8 mm, is hollowed out with a groove of complementary shape to that of the tube 8.
• An InfraRed camera is also used, in accordance with that marketed by CEDIP under the reference JADE III. .
• Block 2 is maintained at a set temperature of 10 O. Moreover, a strong acid HCl and a strong base are flown upstream of tube 8.
• This strong acid and this strong base are brought into contact at the inlet E of the tube 8, being placed at a temperature of 10 O.
• This acid and this base then flow in parallel, as illustrated in FIG. , and generate a rapid and exothermic neutralization reaction. In other words, their bringing into contact generates a local heat flow, which immediately has a high value, then decreases rapidly, according to a profile corresponding to that of FIG. 12.

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• 2008
  • 2008-03-03 FR FR0851355A patent/FR2928209B1/fr not_active Expired - Fee Related
• 2009
  • 2009-03-02 WO PCT/FR2009/050331 patent/WO2009115717A2/fr active Application Filing
  • 2009-03-02 US US12/920,380 patent/US20120094392A1/en not_active Abandoned
  • 2009-03-02 EP EP09721884A patent/EP2250488A2/de not_active Withdrawn
  • 2009-03-02 JP JP2010549177A patent/JP2011513743A/ja active Pending

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