WO2012062995A1

WO2012062995A1 - Unit comprising a peltier-effect condensation device

Info

Publication number: WO2012062995A1
Application number: PCT/FR2011/052603
Authority: WO
Inventors: Eric Favre; Alain Durand; Mathieu Weber
Original assignee: Universite De Lorraine
Priority date: 2010-11-09
Filing date: 2011-11-08
Publication date: 2012-05-18
Also published as: FR2967243B1; EP2638335A1; FR2967243A1

Abstract

The invention relates to a heating unit adapted to perform a method including a steam condensation step. The unit comprises an evaporation device designed to evaporate a fluid and a device for condensing steam leaving the evaporation device, said condensation device including a steam collection tube having one end connected to a steam outlet of the evaporation device. The unit is characterised in that the condensation device also comprises: a thermoelectric device (10, 11, 15) including a through-hole in which the collection tube is positioned, an internal surface of the hole forming a cold surface of the thermoelectric device; and a control module (47) for supplying the thermoelectric device with an electric current according to the condensation temperature of the steam passing through the collection tube. The invention is suitable for condensing steam.

Description

Installation comprising a Peltier condensing device

Technical field and state of the art

The invention relates to an installation suitable for implementing a method comprising a vapor condensation step. Such an installation comprises an evaporation device adapted to evaporate a fluid and a device for condensing vapors leaving the evaporation device; the condensing device comprises a vapor collection tube, one end of the tube being connected to a vapor outlet of the evaporation device. Such an installation can in particular be used in the laboratory to condense vapors in reflux heating operations to accelerate or allow a chemical reaction without loss of reagents or products, and to limit solvent emissions. It can also be used for distillation operations to separate the components of a liquid. It can also be used for the implementation of a process for separating molecules in the gas phase by a pervaporation process, etc.

The so-called reflux heating operation is a great classic of laboratory manipulations in chemistry, biology or medical analysis both in the educational and professional fields. The actual embodiment of a reflux heating operation requires a step of heating a liquid contained in a heating block and a step of condensation of the vapors produced by the heating block in order to avoid any effect of concentration of the molecules dissolved in heated liquid and to limit solvent emissions. The condensation function is conventionally provided by a condensation device attached to an outlet of the heating block generally consisting of a reaction vessel (for example a glass-balloon) associated with a heating device. The condensation device is generally a double-walled tube fed, usually in open loop, by water from the drinking water network (tap water). For volatile compounds, the temperature of the tap water is often too high to provide effective condensation and a cryostat is needed to ensure a temperature of the water flowing in the lower double wall. These two options (open tap water system or closed loop water circuit with cryostat cooling) lead to condensing devices that either consume a lot of water for the first case, or are complex and expensive in terms of equipment. for the second case (need to invest in a cryostat, a circulation pump ...). Moreover, these two options present the difficulties related to the use of a liquid in circulation (risk of leaks, development of algae or bacterial contamination, fouling ...).

Description of the invention

The invention proposes a new installation, particularly well suited for the implementation of a method comprising a steam condensation step, and not having all or part of the disadvantages of known installations. Thus, the invention proposes an installation comprising an evaporation device adapted to evaporate a fluid and a device for condensing vapors leaving the evaporation device, the condensation device comprising a vapor collection tube, one end of the tube being connected. on a vapor outlet of the evaporation device. The installation according to the invention is characterized in that the condensation device also comprises: A thermoelectric device having a recess opening into which the collection tube is positioned, an inner surface of the recess forming a cold surface of the thermoelectric device, and

A control module for supplying the thermoelectric device with an electric current according to a condensing temperature of the vapors passing through the collection tube. The thermoelectric device is a device adapted to produce from an electric current a temperature difference between a cold surface and a hot surface of the device. Thus, from the current supplied, the system according to the invention will cool the inner surface of the recess of the thermoelectric device and therefore the collection tube positioned inside the recess.

The evaporation device is for example a heating block comprising a reaction vessel such as a glass-balloon, associated with a heating device such as a Bunsen burner or an electric resistance plate. Such an evaporation device is for example used in a reflux heating system. Such an evaporation device can also be used in a pervaporation installation; in this case, a membrane is inserted into the collection tube and only the vapors passing through the membrane are condensed along the collection tube by the condensation device. When they exit the evaporation device, climb into the collection tube and arrive at the condensation device, the vapors condense. The condensation device of the installation according to the invention does not consume water and consumes only a small amount of electrical energy. In addition, to cool a collection tube, for example a glass tube with a diameter of 1 to 3 cm, a thermoelectric device of small power, of the order of 10 to 30 Watt is sufficient. Since such a thermoelectric device is small, the system according to the invention is small and of reduced weight as well, so that the installation is portable and can very easily be moved from one place to another.

In one embodiment, the thermoelectric device comprises a Peltier module in the form of a hollow tube, an inner surface of the hollow tube forming a cold surface of the Peltier module. In this case, the particular shape of the Peltier module allows the condensation device to easily adapt to the vapor collection tube and makes it possible to obtain maximum efficiency from the condensation device.

In another embodiment, the thermoelectric device comprises N Peltier modules each having a substantially flat cold face, the N Peltier modules being associated to form together a hollow tube having a recess with a cold internal surface. The number of Peltier modules is chosen according to the shape of the section of the vapor collection tube, for example 4 modules for a square section tube, 6 or more modules for a circular section tube, etc. The realization of the thermoelectric device is thus optimized so that the shape of the recess matches at best the shape of the vapor collection tube.

In yet another embodiment, the thermoelectric device comprises:

A ring-shaped connecting member having a opening opening into which the collection tube is inserted,

· N Peltier modules fixed on an external surface of the ring. The connecting member makes it possible to interface the collection tube and the Peltier module (s). The connecting member is made of a good thermal conductive material, for example aluminum. According to one embodiment, the connecting member is in the form of a rigid cylinder with a polygonal outer surface and is pierced by a recess opening (hence its ring shape), an inner wall of which forms the internal surface of the device. thermoelectric. The internal surface and the dimensions of the ring are adapted to those of the collection tube. The connecting member allows for a rigid condensation device, perfectly adapted to the collection tube and inexpensive using Peltier planes modules that are widely available at lower cost in the trade.

In one embodiment, the thermoelectric device is made in two parts which, associated by a hinge means, for example a hinge, and movable between a closed position where the two parts together have a general shape having a opening opening in which is positioned the collection tube, and an open position allowing the passage of the collection tube. The thermoelectric device can thus be easily installed on the collection tube, even in difficult conditions, for example if the collection tube has larger end sections than the sections of the body of the tube to be cooled or if the ends on tube are difficult to access. If necessary, the installation according to the invention may also comprise a device for discharging heat in the vicinity of a hot surface of the thermoelectric device, for example a radiator, possibly ventilated.

If the thermoelectric device comprises N Peltier modules each having a cold surface, the heat removal device may comprise N radiators each having a shape adapted to be in contact with the hot surface of a Peltier module. In a variant also, the condensation device may comprise several thermoelectric devices, positioned next to each other and / or spaced apart from each other along the collection tube. In this case, the control device is preferably adapted to provide each thermoelectric device with an electric current depending on a desired temperature on the inner surface of said thermoelectric device, the electric current being able to be different from one thermoelectric device to the other . It is thus possible to condense the vapors over a greater length of the collection tube. Also, by providing the thermoelectric devices with different currents, it is possible to obtain a temperature gradient on the outer wall and inside the collection tube; it is thus possible to separate the different gases contained in the vapors, depending on their condensation temperature.

The control device provides an electric current depending on the desired temperature and / or the number of thermoelectric devices and / or the number of Peltier modules per thermoelectric device, as will be seen better below.

For example, if a thermoelectric device comprises N Peltier modules, the control module can be adapted to supply an electric current to a number of Peltier modules depending on a desired temperature on the internal surface of the thermoelectric device according to a condensation temperature. vapors circulating inside the collection tube. The control module can thus supply current to only a portion of the Peltier modules. In other words, the temperature is regulated here by regulating the number of Peltier modules supplied with current. In another example, the same current is supplied to all Peltier modules of the same device thermoelectric, and this current is a function of the desired temperature. In yet another example, where the condensing device comprises a plurality of thermoelectric devices positioned along the collection tube, different currents are supplied to the thermoelectric devices, so as to obtain a temperature gradient along the tube.

Finally, in a preferred version of the invention, the control module and the thermoelectric device or devices are grouped together in one and the same housing or in two half-housings associated by means of articulation to form a housing, in which the housing comprises an open recess whose shape is adapted to the shape of the collection tube, and wherein the housing is adapted so that the inner surface of the thermoelectric device comes into contact with the outer wall of the collection tube when the condensation device is positioned on the collection tube.

Brief description of the figures

The invention will be better understood, and other features and advantages of the invention will emerge in the light of the following description of embodiments of heating installation according to the invention. These examples are given in a non-limiting manner. The description is to be read in conjunction with the accompanying drawings in which Figures 1 to 7 show elements that can be used for the implementation of an installation according to the invention.

Description of an embodiment of the invention

The essential elements of the invention are Peltier modules that transform an electric current into a temperature difference. Each module includes a cold surface and a hot surface, and transfers available energy in the vicinity of the cold surface to the hot surface. Under optimum performance conditions, such a Peltier module consumes a current of about 2 amperes at a voltage of 12 V, to evacuate an energy of the order of 0.5 to 1 Joule.

An installation according to the invention comprises an evaporation device and a device for condensing vapors. In the example of FIG. 4, the evaporation device is a heating block 1 conventionally comprising a heating container, for example a liquid heating flask 2, and a heating means such as a Bunsen burner or a plate. 3. The condensation device comprises a vapor collection tube 41, one end of which is connected to an outlet of the vapors of the evaporation device.

The condensation device of the installation according to the invention also comprises:

A thermoelectric device 10, 11, 15 in the form of a hollow tube comprising a cold internal surface whose shape is adapted to a shape of the collection tube and

A control module 47 for supplying the thermoelectric device with an electric current depending on a condensing temperature of the vapors passing through the collection tube. Figures 1 to 3 show different modes of association of Peltier modules to form the thermoelectric device of a condensation device according to the invention. In the example of FIG. 1, the thermoelectric device comprises a single Peltier module in the form of a hollow tube 10 whose inner surface corresponds to the cold face of the Peltier module. In the example of FIG. 2, the thermoelectric device 11 comprises N = 4 Peltier modules 12 each having a cold face and a hot face. The Peltier modules are associated to form together a hollow tube whose cold inner surface is adapted to a square section collection tube. In the example of FIG. 3, the thermoelectric device 15 comprises N = 10 to 20 associated Peltier modules 16 to form a hollow tube of which a section comprises N sides. The larger N is, the more the section of the hollow tube approaches a circular shape. The Peltier modules can be associated with each other by an adhesive tape for example, or by means of a more rigid structure such as a hollow metal cylinder.

FIG. 4 shows a thermoelectric device comprising N = 2 Peltier modules 43, 44 associated by means of a ring-shaped connecting member 42. In the example shown, the ring has a substantially parallelepipedal external shape and is pierced with an opening opening whose wall forms the inner surface of the thermoelectric device. The N = 2 Peltier modules are planar and are fixed on two opposite sides of the ring, sides parallel to a longitudinal axis of the recess corresponding to the axis of the collection tube. In a variant, two other Peltier modules can be added on the other two sides of the ring. In a variant also, the outer sides of the ring not covered by a Peltier module are covered with a thermal insulating coating. Thus the Peltier modules only cool the ring and dissipate only the energy provided on the wall of the recess by the collection tube.

More generally, the ring may be in the form of a rigid cylinder with a polygonal outer surface, for example a four-sided polygon (FIG. 4), six, eight or more sides. The flat outer faces of the ring allow the attachment of flat Peltier modules, widely available and inexpensive.

The ring is rigid, non-deformable. Such an embodiment of the thermoelectric device according to the invention allows use on collection tubes of small or very small diameters, for example of the order of 1 to 3 cm or less.

The shape and dimensions of the inner recess of the ring are adapted to the shape and dimensions of the collection tube. Alternatively, the ring may also be pierced with a plurality of recesses opening, parallel, to allow the use of a single thermoelectric device on several tubes simultaneously. The ring is made of a rigid material good thermal conductor, for example a metal such as aluminum, copper, etc.

In the example of Figure 4 also, a ventilated radiator 45, 46 is fixed on the hot surface of each of the Peltier modules to evacuate heat to the outside. Depending on the heat to be dissipated, the ventilated radiator (s) may be replaced by any other suitable means for evacuating the heat, for example by a simple radiator. In the example of FIG. 4 again, the control module 47 supplies a current to a number of Peltier modules according to the desired temperature. Thus, the greater the number of Peltier modules supplied with current, the higher the temperature can be lowered on the cold surface of the thermoelectric device or devices. Preferably, the current supplied to each Peltier module is chosen so that said module operates at its maximum efficiency. As an indication, the two Peltier modules of 40 mm by 40 mm, supplied in series by a current of 2 amperes at 12 volts, make it possible to obtain a temperature of the order of 0 ° C. on their cold side, when the module is at room temperature. Unfortunately, the small size of the Peltier modules makes it possible to produce a condensing device of small size, of dimensions of the order of ten centimeters, and of reduced weight, of the order of a few hundred grams. The condensation device can thus be easily installed on any vapor collection tube, and be easily transportable from one tube to another and from one place to another.

In the example of FIG. 5, the condensation device comprises two thermoelectric devices 51, 52 positioned relative to each other so as to form together a through recess adapted to the shape of a vapor collection tube. . The control device is here adapted to provide each thermoelectric device with a different current so that the cold surface of the thermoelectric devices is different. This makes it possible to obtain a temperature gradient on the internal face of the opening opening.

Finally, a condensation device according to the invention comprises a housing in which are grouped together the control module and the thermoelectric device or devices. The housing can be made in a single portion 61 (Figure 6) or in two parts 71, 72 assembled by a hinge means such as a hinge 73 (Figure 7). The housing comprises a through recess whose shape is adapted to the shape of the collection tube. And the housing is adapted for the inner surface of the thermoelectric device (s) to come into contact with the outer wall of the collection tube when the condensation device is positioned on the collection tube.

The electrical energy necessary for the operation of the condensation device can be supplied to the control module either by a battery or by an electrical energy distribution network, via a current transformer if necessary.

Claims

1. Installation adapted for the implementation of a process comprising a steam condensation step, an installation comprising an evaporation device adapted to evaporate a fluid and a device for condensing vapors leaving the evaporation device, the device for condensation comprising a vapor collection tube, one end of the tube being connected to a vapor outlet of the evaporation device, the installation being characterized in that the condensation device also comprises:

A thermoelectric device (10, 11, 15) comprising a through recess, within which the collection tube is positioned, an inner surface of the recess forming a cold surface of the thermoelectric device and

"A control module (47) for providing the thermoelectric device with an electric current dependent on a condensing temperature of the vapor passing through the collection tube.

2. Installation according to claim 1, wherein the evaporation device is a heating block comprising a reaction vessel associated with a heating device.

3. Installation according to one of claims 1 to 2 wherein the thermoelectric device comprises a Peltier module shaped hollow tube (10), an inner surface of the hollow tube forming a cold surface of the Peltier module.

4. Installation according to one of claims 1 to 2 wherein the thermoelectric device (11, 15) comprises N Peltier modules (12, 16) having a substantially flat cold surface, the N Peltier modules being associated to form together a hollow tube having a recess with a cold internal surface.

5. Installation according to one of claims 1 to 2 wherein the thermoelectric device comprises:

A ring-shaped connecting member (42) having a through opening into which the collection tube is inserted,

• N Peltier modules (43, 44) fixed on an external surface of the ring.

6. Installation according to claim 5, wherein the ring has the shape of a rigid cylinder polygonal outer surface and pierced with a recess opening, an inner wall forms the inner surface of the thermoelectric device.

7. Installation according to one of claims 5 or 6, wherein the ring is made of a rigid material and good thermal conductor such as a metal.

8. Installation according to one of the preceding claims, wherein the thermoelectric device is made in two parts associated by a hinge means, for example a hinge, the two parts being movable between a closed position where the two parts together have a general shape having a recess opening in which is positioned the collection tube, and an open position allowing the passage of the collection tube.

9. Installation according to one of the preceding claims also comprising a device (45, 46) for discharging heat in the vicinity of a hot surface of the thermoelectric device.

10. Installation according to claim 9, wherein:

The thermoelectric device comprises N Peltier modules each having a cold surface,

The heat dissipating device comprises N radiators (45, 46) each having a shape adapted to be in contact with the hot surface of a Peltier module.

11. Installation according to one of the preceding claims, wherein the condensation device comprises a plurality of thermoelectric devices (51, 52) spaced along the collection tube, and wherein the control device is adapted to provide each thermoelectric device a electric current function of a desired temperature on the inner surface of said thermoelectric device, the electric current supplied being different from one thermoelectric device to another so as to obtain different temperatures along the wall of the tube.

12. Installation according to one of the preceding claims, wherein the control module and the thermoelectric device or devices are grouped in the same housing, or in two half-boxes associated by a hinge means to form a housing, wherein the housing comprises a through recess whose shape is adapted to the shape of the collection tube, and wherein the housing is adapted so that the inner surface of the thermoelectric device surrounds the collection tube when the condensation device is positioned on the tube collection.