WO2017085433A1

WO2017085433A1 - Enthalpy exchange device

Info

Publication number: WO2017085433A1
Application number: PCT/FR2016/053031
Authority: WO
Inventors: Alain Fernandez De Grado; Philippe HAFFNER
Original assignee: Haffner Energy
Priority date: 2015-11-20
Filing date: 2016-11-21
Publication date: 2017-05-26
Also published as: FR3044083B1; FR3044083A1

Abstract

Device (1) for exchanging between at least a fluid A and at least a fluid B, comprising a chamber (2), comprising an outlet (32) for fluid A, an inlet (31) for fluid A, an outlet (42) for fluid B, an inlet (41) for fluid B, characterized in that the position of the inlets and outlets for fluid A and B define two distinct zones within the chamber, a first zone of action of fluid A (21) between the inlet and outlet for fluid A and a second zone of action for fluid B (22) between the inlet and outlet for fluid B, and in that independent solid particles (5) forming a mobile transfer medium are placed in a heap inside the chamber (2), in the zone of action of fluid A (21) and in the zone of action of fluid B (22), and in that an inlet (51) for the said transfer medium is placed at one end of the chamber (2) and in that an outlet (52) for the said medium (52) is placed at the other end of the chamber (2), and in that a means (8) of transferring the said transfer medium is interposed between the said medium outlet (52) and the said medium inlet (51) ensuring that the said medium circulates in a loop, and in that it further comprises a condensate collection means (10).

Description

ENTHALPY EXCHANGE DEVICE

Field of the invention

The present invention relates to the field of thermal energy exchange between a hot fluid and a cold fluid, particularly in the energy process industry.

State of the art

In order to proceed with an exchange of thermal energy between a hot fluid, whether it is gas or liquid, and a so-called cold fluid that will heat up in thermal contact with the hot fluid, it is common to use heat exchangers.

Most exchangers, whether they are plate heat exchangers, coil heat exchangers or tubular heat exchangers, are said to be static and are subject to fouling, corrosion or abrasion, if one of the heat transfer fluids comprises corrosive or abrasive undesirable elements.

This is the case, for example, in combustion or incineration plants, where the hot fluid is smoke not yet filtered, or even in the gasification plants, where the hot fluid is unfiltered raw syngas we want to recover the energy. Often the operating conditions are very demanding, especially in terms of high temperature (more than 600 ° C) or fouling by dust whose ability to adhere to the walls of equipment is enhanced by the high temperature. In order to overcome the problems of corrosion in incinerators for cogeneration or the production of superheated steam, due to the often important presence of acid fumes, "

The superheating temperature of the steam produced is generally limited to less than 420 ° C. in order to maintain a temperature below 500 ° C. on the walls of the superheating tubes, which greatly degrades the electrical efficiencies with respect to an installation which would produce steam under improved conditions at about 520 ° C.

Static installations are facilities that are difficult to clean after fouling and that it is expensive to replace when the exchange surfaces are corroded by attacks of high temperature chlorine.

In addition, in many cases, the hot fluid is a gas having a very low thermal conductivity, generally less than 0.05 W / mK. The consequence is a high nip between the supply fluid and the calorie-receiving fluid, that is to say that there remains a high temperature difference between the two fluids, even in the context of a countercurrent exchange despite important trading surfaces. In a biomass steam boiler, this nip often exceeds 100 ° C.

Description of the invention

For example, when producing energy by combustion, it is necessary to cool the fumes by transferring the heat contained in the fumes to a cold fluid using a heat exchanger.

Conversely, the same invention can be used to transfer cold between fluids. The invention also relates to the latent heat exchange when at least one fluid undergoes a change of state which releases or absorbs latent heat, in addition to the sensible heat. This is why the invention relates to the exchange of total enthalpy (sensible heat plus latent heat) between fluids.

The present invention aims to overcome the drawbacks of the state of the art by providing an exchange device between at least one fluid A and at least one fluid B, comprising an enclosure, comprising a fluid outlet A, an inlet fluid A, a fluid outlet B, a fluid inlet B, characterized in that the position of the fluid inlets and outlets A and B define two distinct zones in the chamber, a first fluid action zone A between the fluid inlet and outlet A and a second fluid action zone B between the inlet and the fluid outlet B and in that independent solid particles forming a mobile transfer medium are placed in a pile in the enclosure, in the fluid action zone A and in the fluid action zone B and in that a media inlet is placed at one end of the enclosure and in that a media outlet is placed at the other end of the enclosure and that means for transferring the media is interposed between the media output and the media input providing the media loop.

In the context of the present invention, the term "enclosure" means a structure in which said transfer medium is present in a packed form.

Advantageously, the horizontal section of said enclosure is constant between the transfer media input and the transfer media output. So, the transfer of the transfer medium is homogeneous regardless of the position of the solid particles constituting it.

In the context of the present invention, the term "heap" means that throughout the enclosure, the transfer medium forms a homogeneous granular stack and that inside the enclosure there is there is no empty volume separating it from different discrete transfer media areas and that the weight of the transfer medium present in the highest fluid action zone is applied in whole or in part to the transfer media present in the area of lowest fluid action. For the sake of clarity, it is pointed out that the present invention therefore does not relate to devices or methods in which the transfer medium is in the form of a fluidized bed. In the context of the present invention, the term "exchange" means an exchange of materials and advantageously an exchange of dust or any other undesirable element present in the fluid A. The term "exchange" also means an energy exchange and advantageously an enthalpy exchange.

In the context of the present invention, the term "zone" or "zone of action" intends to designate a portion of the interior volume of the chamber in which a single fluid will circulate and which will constitute a direct or indirect contact zone between said fluid and the transfer medium. These zones can be defined structurally, in the case where a fluid will flow between its inlet and its outlet, inside the enclosure, in a heat exchanger. Alternatively, an area will be defined by the position of the fluid inlet and outlet. For example, an inlet and a fluid outlet placed on either side of the enclosure will define an area that corresponds to the portion of the enclosure disposed between said inlet and said outlet. In order to prevent two zones of action from being superimposed, the person skilled in the art is able to determine the ideal position of each inlet and outlet, particularly as a function of the physico-chemical nature of the fluid and its speed. of circulation.

According to a preferred embodiment of the invention, said enclosure is sealed. This means in particular that it does not include any opening to the outside other than those mentioned specifically.

In the context of the present invention, the media transfer means may be interposed within the enclosure between the media output and the media input. In this case, the media output is also connected to the media input via the outside of the enclosure to allow loop circulation of said media. Alternatively or in a complementary manner, the media transfer means is interposed between the media output and the media input outside the enclosure.

According to a preferred embodiment of the invention, the axis passing between said input and said transfer media output has an inclination of at least 45 ° relative to the horizontal.

According to a preferred embodiment of the invention, the transfer medium has a void ratio of at least 20%.

According to a preferred embodiment of the invention, the independent solid particles are spheres with a diameter of between 3 mm and 100 mm.

According to a preferred embodiment of the invention, the independent solid particles are solid bodies pierced with at least two through holes. _r

- 6 -

According to a preferred embodiment of the invention, the media transfer means of the media is placed outside the enclosure and comprises an Archimedean screw.

According to a preferred embodiment of the invention, the media transfer means of the media is placed outside the enclosure and comprises transport buckets driven by an elevating mechanism.

According to a preferred embodiment of the invention, the media transfer means of the media is placed outside the enclosure and comprises a plate driven by a jack.

According to a preferred embodiment of the invention, the media transfer means of the media is placed outside or inside the enclosure and comprises an internal ascending asymmetric drag lift means.

According to a preferred embodiment of the invention, means for regulating the flow rate of at least one of the fluids is associated with the inlet and / or the outlet of said fluid.

According to a preferred embodiment of the invention, the device further comprises means for controlling the transfer rate of the particles of the media.

According to a preferred embodiment of the invention, said device further comprises a means for cleaning the particles of the transfer medium.

According to a preferred embodiment of the invention, said device further comprises a condensate cleaning means. According to a preferred embodiment of the invention, said device further comprises a means for screening the particles of the media ensuring among other things the elimination of broken or agglomerated elements. According to a preferred embodiment of the invention, said device further comprises a condensate recovery means.

According to a preferred embodiment of the invention, said device is an enthalpy exchange device and comprises at least one sealed heat exchanger placed inside said enclosure in contact with said transfer medium, and connected to said input and at said output of one of said fluids.

According to a preferred embodiment of the invention, the independent solid particles constituting the transfer medium consist of a material of thermal conductivity greater than 0.2 W / mK.

According to a preferred embodiment of the invention, the independent solid particles consist of two different materials and one of the materials constitutes the outer shell of the particle and the other material constitutes the core of the particle and has a temperature less melting than the material constituting the outer casing.

According to a preferred embodiment of the invention, said device further comprises a heat pump connected to the fluid outlet B.

The present invention also relates to a remarkable exchange process in that it comprises a step of circulating a transfer medium, composed of heap-independent solid particles in the same chamber, between a first action zone A in which circulates a fluid A and an action zone B in which a fluid B circulates, characterized in that said transfer medium is sent to the action zone A after having circulated in the action zone B.

According to a preferred embodiment of the invention said method comprises a step of collecting the condensates formed in contact with one of the fluids and said transfer medium.

According to a preferred embodiment of the invention, the fluid A is hotter than the fluid B.

According to another preferred embodiment of the invention, the fluid A is less hot than the fluid B.

According to a preferred embodiment of the invention, the fluid A is a hot gas that circulates through the transfer medium, the fluid B is liquid water and / or water vapor that circulates in a heat exchanger of heat and the transfer medium flows between the zone A and the zone B, so that the enthalpy of the fluid A is transmitted to the fluid B.

According to a preferred embodiment of the invention, the flows of the fluids A and B are regulated so that the flow rate of one of the fluids, considered clean, is greater than 1% more than the flow rate of the other fluid, considered dirty, leaking clean fluid to the dirty fluid and preventing the reverse.

According to a preferred embodiment of the invention, the fluid A is a gas and the fluid B is cooled by a heat pump, after passing on said transfer medium, and is then used to condense the condensable vapor contained in the gas A.

According to a preferred embodiment of the invention, the transfer medium collects the undesirable elements of the fluid A in the zone A and the said transfer medium is washed by the fluid B in the zone B.

According to a preferred embodiment of the invention, said transfer medium also circulates in a zone C, in the middle of a fluid C comprising a collecting agent able to improve the collection capacity of said media of transfer.

According to a preferred embodiment of the invention, the hottest fluid has an inlet temperature in the enclosure greater than 150 ° C., still more preferably at 400 ° C. and quite preferably above 600 ° C. vs.

According to a preferred embodiment of the invention, the method according to the invention implements a device according to the invention.

Advantages of the invention

One of the advantages of the invention is that the high thermal inertia of the mobile heat transfer medium, associated with its high thermal conductivity and diffusivity, makes it possible to reduce the thermal nip between the supply and the enthalpy receiver fluids, respectively.

Another advantage is that the heat capacity of the mobile heat transfer medium can be defined in such a way that the enthalpy transfer takes place at the temperatures required for the enthalpy receiving fluid, and that this makes it possible in particular to recover all or part of the heat transfer medium. the latent heat of the enthalpy-introducing fluid that would otherwise be lost.

Another advantage is that the high thermal inertia of the mobile heat transfer medium dampens the enthalpy variations of the heat transfer fluid introducing enthalpy, thus allowing a more stable transfer of enthalpy.

Another advantage is that the speed of movement of the heat transfer medium can be adjusted in real time according to the required enthalpy exchange power, thus making it possible to adjust, for example, the parameters of the peripheral processes using the fluids heat transfer agents involved in the exchange of enthalpy through the invention, for example combustion or gasification processes.

Another advantage is that the exchange of enthalpy takes place in the same enclosure, thus avoiding the use of an auxiliary heating furnace which should ensure the temperature rise of balls or any other moving mass and also avoiding constraints related to very high temperature transfers.

Another advantage is that the heap displacement of said transfer medium ensures a homogeneous transfer of the particles in the chamber and therefore an optimal transfer of the enthalpy from one action zone to another.

Thus, the flow of the fluid and / or the transfer medium is a piston flow. By "piston flow" is defined a unidirectional flow in which in a plane perpendicular to the flow, all the nets move with a uniform velocity and all the physical quantities are identical. In such a flow, the recovery of the enthalpy is optimal.

Another advantage is that it is possible to choose a heat transfer media insensitive to acid attacks, for example alumina balls (AL203), which allows a low thermal pinch and improves the performance of the heat exchange between the fluids at play .

Another advantage is that depending on the type of heat transfer medium chosen, it is possible to work with very hot fluids (greater than 150 ° C, 400 ° C, see 600 ° C).

Another advantage is that the mobile heat transfer medium can be set in motion slowly, which is good less energy intensive than a sand fluidization movement in a combustion or gasification furnace.

Another advantage is that the invention makes it possible to carry out a condensation of vapors contained in the hot gaseous fluid, without requiring the use of a separate flue gas condenser, unlike conventional installations of flue gas condensers.

Another advantage is that the mobile media does not have to be cleaned in situ, unlike traditional fixed-fill condensation plants which, by their nature, can not easily be removed from the reactor for cleaning.

Another advantage is that the heat transfer fluids charged with dust are partly freed of their dust by collecting them on the surface of the elements of the mobile heat transfer medium, thus facilitating subsequent processing steps.

Other advantages and characteristics of the invention are described below according to the possible embodiments of the invention.

The descriptions refer to the following figures in the appendix:

FIG. 1 diagrammatically represents the device of the invention according to a version with two zones of circulation of fluid through the mobile medium.

FIG. 2 represents a variant of the invention in which one of the exchange zones comprises a sealed heat exchanger and thermal fins.

FIG. 3 represents a variant of the invention in which a media transfer means of the media is represented in downward movement.

FIG. 4 represents a variant of the invention in which a means for transferring particles from the media is represented in upward motion.

FIG. 5 represents a variant of the invention in which a means for condensing the vapors contained in a cooled gas is represented.

FIG. 6 represents a variant of the invention in which another means of condensing the vapors contained in a cooled gas is represented.

Presentation of an embodiment

The present invention relates to an enthalpy exchange device between two fluids, mainly in an energy production process. It is particularly useful in the case of cogeneration with steam production by combustion of raw material to produce electricity using a steam turbine, and the heat discharged into a heat network. It is also useful in the case of the production of synthetic gas called Syngaz by a process of pyrolysis, thermolysis and / or gasification of organic raw material. Obviously, any other process involving enthalpy exchange can usefully utilize the invention.

The fluids can be in gaseous or liquid or mixed form if the conditions of temperature and pressure allow a biphasic state.

The notion of enthalpy encompasses the sensible heat of fluids and the latent heat which can also be exchanged in case of phase change during heat exchange. The enthalpy involved during a phase change (so - called latent heat) is often very large and can represent 2 to 10 times more energy than the enthalpy at play during the temperature rise before or after the change of temperature. phase (called sensible heat).

This is, for example, the case if a liquid fluid becomes gaseous during the operation, or if a gaseous fluid condenses during the operation. Thus, fumes from the combustion of raw material in a boiler contain water vapor which can advantageously be condensed at the end of the fumes treatment, before their exit into the atmosphere. The latent heat thus recovered, at least partially, can be reused in a heat network. In the context of the invention, it is therefore a question of increasing the temperature of a cold fluid from a hot fluid or vice versa, but also possibly of exchanging all or part of the latent heat of the fluids. In the remainder of the description, this exchange will be called the exchange of enthalpy, concerning an exchange of sensible heat alone, or of latent heat alone, or both.

According to the invention, an intermediate solid mass is put into play to ensure an exchange of enthalpy between two fluids. To simplify the description of the invention, the fluids that come into play in the device will be called fluid A and fluid B.

The solid mass consists of a set of individual solid particles which are used without cohesion between them. This gives a mass of particles whose size and shape allow a natural flow by the effect of gravity.

The mass is intermediate because it plays a role of media that will constantly warm up and cool under the influence of the fluids involved.

For convenience, the following description focuses on the goal of exchanging heat from a higher temperature fluid A to a lower temperature fluid B. However, the reasoning can be reversed by considering that the fluid A has a temperature ,

- 14 - less than that of fluid B and that the objective is to exchange heat from B to A.

The invention relates indifferently to both agents.

In the operating principle of the invention, the solid mass serves as a medium for the transfer of enthalpy. The media will capture the enthalpy of the fluid A, possibly store it and then transmit it to the fluid B, while preventing or limiting the mixing between the fluids, because the objective of the invention is to exchange the heat without exchanging fluids.

The storage of heat or thermal inertia is one of the characteristics of the invention. Indeed, the transfer media has a mass that allows to accumulate enthalpy under the effect of its rise in temperature and according to its specific thermal capacity expressed in the unit J / (kg.K). Thus, it is necessary to have a high mass media and / or high thermal mass capacity which has a high thermal inertia. Concretely, to guarantee a good stability of the thermal exchanges, it is preferable that the total enthalpy contained in the media represents at least 2 times the enthalpy that the fluid A will bring to the fluid B.

According to a variant of the invention, the transfer medium may contain a material which changes phase during its use so as to also benefit from the latent heat of phase change of this material, which also makes it possible to have a more great thermal inertia.

For example, a hollow refractory molybdenum steel ball whose melting temperature exceeds 2600 ° C., filled with an aluminum alloy whose melting point is 600 ° C., can store, during the solid-liquid phase change of aluminum at this fixed temperature of 600 ° C, more than 370kJ / kg of aluminum is the equivalent of the sensible heat of a kg of aluminum heating up to 400 ° C.

The thermal inertia of the media is sought because it ensures a storage of the enthalpy that stabilizes the heat exchange between the fluids. Indeed, the thermal capacity of a particular fluid and especially a gas is, except exception, lower than that of a solid. Thus, in the event of a slight variation in the temperature of the fluid A, in the absence of inertia by the media, the temperature of the fluid B would also vary. Due to the inertia of the media, the fluid B follows a much more uniform temperature evolution during its progression in the device according to the invention.

In addition, according to a variant of the invention, the enthalpy storage allows a discontinuous mode of operation: in a first step, the fluid A brings its enthalpy to the transfer medium without the fluid B circulating, then in a second time, the fluid B circulates in the device and collects the stored enthalpy.

Preferably, the thermal inertia makes it possible to operate continuously, with a heat exchange power of the fluid A to the transfer medium that is different from that between the transfer medium and the fluid B. Thus, it is possible to collect a lot of enthalpy from the fluid A and to return little, the balance being stored in the media; or conversely to take little and recover more towards the fluid B, the balance being removed from the transfer media. Obviously, it is necessary that the balance equilibrium in the long term.

According to a variant of the invention, it is possible to managing an imbalance between the enthalpy provided by the fluid A and that received by the fluid B by using an auxiliary means for heating or cooling the media.

Another advantage of the invention is that the transfer medium can provide a high-power heat exchange, both for the transfer from the fluid A and for the transfer to the fluid B. This result is obtained by the use of a media having numerous cavities easily traversed by the fluid. For example, a media consisting of balls perforated on 25% of their volume guarantees a porosity (ratio of the volume of vacuum to the total volume of solid + vacuum) of more than 50% and therefore a good circulation of the fluid in all the zone of enthalpy exchange. This is important if the fluid that passes through the media carries "clogging" particles that can settle in the media and cause a gradual clogging of cavities in which the fluid flows.

According to a variant of the invention, it is possible to use simple spheres, the packing of which in a given volume makes it possible to preserve porosities between the spheres, leaving a free passage for a fluid passing through.

In addition, the exchange power is improved if the media has a good diffusivity, that is to say if the material has a strong ability to transfer heat. The diffusivity coefficient defined by D = lambda / ro / C (where lambda = thermal conductivity, ro = density and C = specific heat capacity) is preferably greater than 0.2 10 ^{~ 6} m ² / s.

In addition, the geometry of the media elements is preferably defined to ensure the presence of a large developed area swept by the delivery fluid or enthalpy sensor, said surface being the seat of the heat exchange. Thus, it is advantageous that the media elements have a large developed surface and a low material thickness in order to facilitate the enthalpy exchanges. The preferred compactness parameter, defined as the ratio of the developed surface area to the solid volume, is greater than 3 m ² / m ³ , which corresponds, for example, to ball-shaped particles 30 mm in diameter and pierced by 2 orthogonal holes with a diameter of 10 mm.

Finally, the exchange power is improved if the flows of fluid through the transfer media are in a hydraulic or aeraulic regime at high speed or turbulent which enhances the performance of convective heat exchange on the surface of the transfer medium. For example, according to a preferred solution, the dimensioning of the device will ensure a fluid flow rate at a speed greater than 1 m / s for liquid and greater than 3 m / s for gas.

Still according to the invention, the transfer medium must withstand the operating constraints provided by the fluids used.

For example, if fluid A has a temperature above 1200 ° C, the transfer media must withstand such a temperature, and it can not be composed of aluminum that melts at 660 ° C. A recommended solution is to use molded spheres composed of alumina ceramics. The temperature resistance thus reaches limits greater than 1100 ° C. or even 1800 ° C. depending on the purity of the alumina.

By another example, the use of a refractory metal of the alloy molybdenum type makes it possible to have a material whose melting point is greater than 2200 ° C and whose mechanical strength is greater than that of an alumina ceramic.

In addition, if the fluid A is a smoke containing sulfur or chlorine and moisture, in case of condensation of water vapor during the heat exchange and cooling of these fumes, sulfuric acid or Hydrochloric acid can form and rapidly corrode the transfer media. In this case, the material constituting it must be chosen so as to withstand a pH generally less than 3.

Furthermore, the fluids may contain suspended elements that may be deposited on the transfer medium and thus lead to its fouling. For example, flue gas combustion boiler contain dust that may deposit on any available solid surface, so the transfer media with the potential to gradually reduce the porosity of the latter. The circulation of fluids and the efficiency of thermal exchanges would then be degraded. To solve this problem, the device according to the invention advantageously comprises a washing means of the transfer media, regular or continuous. This is described below.

Finally, according to the invention, the transfer medium is set in circulation movement inside the enclosure of the exchanger which assumes that the transfer medium is composed of individual particles that can be moved without bonding between they and without mechanical blocking that would create a single block impossible to move. It is also advantageous that the elements constituting the transfer medium have sufficient mechanical strength to support the weight of the stacking, especially in the lower part. It is also better that the eventual movement of these elements does not break them or abrase them too quickly, so as not to have to replace them too often, due to unavoidable wear.

Thus, the heat transfer transfer medium is composed of individual particles which may be balls or individual elements of Raschig ring type, Perl saddle, ... which are placed in a pile in the enclosure of the exchanger.

Advantageously, the elements are of globally spherical shape. The spherical shape facilitates the circulation of the elements in the enclosure without a particle blocking effect between them can occur.

Other forms are also possible, as long as they comply with the specifications described above.

For example, the elements may be provided with one or more perforations. These perforations are intended to facilitate the flow of fluids through the bed of particles, thanks to the high porosity thus obtained.

Thus, the stack of the transfer medium is preferably ially mechanically resistant, porous for the circulation of the fluid, massive to improve the thermal inertia, having a large surface developed to ensure a high-power heat exchange and conductivity thermal system to accelerate heat transfer.

According to the invention, the general architecture of the device 1 shown in FIG. 1 comprises an enclosure 2 in which the transfer medium 5 is discharged, an inlet 31 of fluid A, an outlet 32 of fluid A, an inlet 41 of fluid B and an output 42 of fluid B. The portion of the enclosure between the inlet 31 and the outlet 32 defines a first zone 21, and the part of the enclosure between the inlet 41 and the outlet 42 defines a second zone 22

The transfer media 5 is discharged from a media inlet 51 and is evacuated from the enclosure 2 by a media outlet 52. The transfer media 5 flows between the inlet and the outlet. If the enclosure 2 is generally vertical, the flow can be from top to bottom or from bottom to top. If the circulation is carried out from top to bottom in the enclosure 2, it is necessary to have an external means 8 for transferring the media from the bottom to the top, in order to reinject the media into the enclosure 2 from above . If the circulation is opposite, the external transfer means 8 from top to bottom may be a simple conduit in which the media falls by gravity. But the flow of the transfer media from bottom to top in the chamber 2 must be assisted by an internal transfer means 9 described below.

According to one variant of the invention, the external transfer means 8 can be integrated in the enclosure 2 of the device according to the invention, in a reserved zone which does not have the main function of ensuring the exchanges of enthalpy between the fluids.

The enclosure 2 is preferably of a stretched shape, that is to say that among its three characteristic dimensions (height, length, width), one of the dimensions is large compared to the others, in order to promote the implementation. place a fluid flow from their entry to their exit, so that all the fluid portions that arrive in the enclosure 2 stay there for an equivalent period and circulate in the media along the same path. A more compact form of enclosure (the three dimensions having about the same value) would be less efficient, because some portions of the fluid could stay less for a long time by following short circuits in the media, to the detriment of efficiency and homogeneity of transfers.

The enclosure 2 may consist of a set of separate channels placed side by side, each channel being equipped with a specific inlet and a fluid outlet, so that each channel can be seen as a specific enclosure used of the same way as the overall speaker described here.

Advantageously, the enclosure 2 is insulated so as to minimize thermal leakage that could affect the performance of the heat exchange.

According to one embodiment of the invention, in the first zone of action 21 of the fluid A, the fluid A is introduced into the chamber 2 through the inlet 31, circulates in the transfer medium, provides it with caloric energy (or removes heat energy in the symmetrical cooling version as indicated at the beginning of the description of the invention) and is discharged through the outlet 32. During its journey, the fluid A cools and can even reach its maximum temperature. condensing temperature which allows to transmit to the media all or part of the latent heat of the fluid A.

On its side, in its second zone of action 22, the fluid B is introduced into the chamber 2 from the inlet 41 to the outlet 42. It circulates in the media and captures the heat of the media through.

In addition, the transfer medium circulates continuously or discontinuously between the two zones of action, which allows it to ensure an enthalpy transfer from the zone A to the zone B. If the circulation is discontinuous, the transfer is done in two stages: first the fluids circulate and exchange enthalpy with the immobile media present in each zone of action up to to reach its saturation in enthalpy, then the media is set in motion to change zone, then it is again immobilized. Then the fluids exchange enthalpy again with new media items that have just arrived in their respective area of action.

Continuous circulation is more preferred because it makes the exchanges more regular, but the management of the flow of circulation is more complex and requires a more elaborate regulation device.

An advantage of the invention is that the change in the flow rate of the transfer media allows adjustment of the power of the enthalpy exchange. Moreover, thanks to the circulation of fluids in the heart of the circulating media, the enthalpic exchange is very efficient and results in a small temperature difference (or nip) between the fluids (generally less than 50 ° C), where a traditional plate heat exchanger could not have a nip less than 100 ° C, especially if the fluids are very high temperature gases.

A mixture between the fluids A and B flowing freely in the transfer medium 5 can occur at the boundary between the two action zones. This can be problematic, for example, if one of the fluids is considered dirty with respect to the other.

According to a variant of the invention, the mixing is limited by the use of a regulation of the fluid flow rates A and B, so that the flow rate of one of the fluids, considered clean, is greater by more than 1% at the flow rate of the other fluid, considered dirty, ensuring leakage of the clean fluid to the dirty fluid and preventing the reverse.

According to another variant of the invention, the mixture is limited by the installation of an obstacle to the exchange of fluids by means of a separating plate 7. plate 7 is advantageously calibrated to generate a pressure drop of more than 10 Pa, thus limiting the exchange of fluid at the border. In order to allow the circulation of the media, this plate has one or more openings 71 and is rotated by a motor equipment not shown. The rotation of the openings allows communication between the zones of action and therefore the transfer of particles from the media.

The mixing of fluids between zones can also be limited by the installation of a bottleneck in the enclosure in place of the separating plate 7, leaving for example a section of free passage between the two zones of 30 % of the total section in each area.

According to a variant of the invention, as indicated in FIG. 2, the fluid B circulates separately in a sealed circuit 6 of coil type or exchanger plate. This sealed circuit is placed at the periphery of the enclosure 2 and / or internally distributed throughout the second zone of action 22, to facilitate the transfer of enthalpy from the media to this circuit. The sealed circuit is traversed from an inlet 61 to an outlet 62 by the fluid B. One of the advantages is that the fluid B may have a pressure different from that prevailing in the enclosure. Another advantage is that the mixing between the fluids A and B is then impossible.

Conversely, the fluid A can circulate in a sealed circuit and the fluid B freely pass through the transfer medium.

The scenario of the two fluids circulating in a sealed circuit with the transfer medium 5 serving as an intermediate is also possible.

According to a variant of the invention, the media of Transfer 5 crosses successively three zones of heat exchange, each zone being traversed by a specific fluid, named for description A, B and C. For example, this organization makes it possible to ensure a heat exchange between an enthalpy-introducing fluid. and two fluids B and C enthalpy receptors. In such a case, it will be possible to have a first exchange zone where the fluid A flows freely in the transfer medium 5, then a second exchange zone where the fluid B circulates freely in the transfer medium 5 and recovering from the enthalpy of the medium 5, as described above, then a third exchange zone with separate circulation of the second receiving fluid C, in a sealed circuit. This third fluid makes it possible to extract the residual enthalpy at a temperature lower than that of the fluid B.

Other combinations according to this logic of several stages are possible, depending on the nature, the temperature and the pressure of the fluids involved.

The transfer of enthalpy is advantageously improved thanks to the installation of fins 63 in the heart of the enclosure 2, constructed of heat-conducting material, such as for example refractory steel. Any material with the ability to transmit heat is suitable. Typically a material having a lambda thermal conductivity of more than 0.2 W / mK is suitable.

When the transfer medium 5 is out of the chamber 2, it should be moved from the withdrawal port 52 to the reintroduction port 51. For this purpose, when the movement of the transfer medium 5 is high, down in enclosure 2, vertical elevation conveying is required. This can be done by archimedes screw, treadmill, bucket elevator, elevator cylinder or any other mechanical means allowing vertical conveying. The transfer medium, at its outlet from the chamber, is cooled by the enthalpy receiving fluid, which limits the mechanical and constructive stresses of the vertical conveying mechanism of said media.

According to a variant of the invention, as represented in FIGS. 3 and 4, in order to allow transfer of the transfer medium from the bottom upwards to the inside of the enclosure, an asymmetric drag lifting means 9 is used. . This means comprises an axle 91 to which a pivot 93 and two pallets 92 are attached. When the axle 91 is pushed downwards, the pivot 93 allows the pallets to be closed under the effect of the resistance of the transfer medium 5, and the assembly 9 sinks into the media 5. When the shaft 91 is pulled up, the pallets open and cause some particles of the transfer media.

Advantageously the output of the media of the enclosure 2 allows him to provide specific treatments.

For example, the particles of the transfer media 5 are cleaned in order to separate and discharge fouling deposits received during the transfer of the media 5 in the chamber of the device 1. This cleaning can be carried out in a bath of pure water or additive d. cleaning agents such as surfactants, or in a bath of solvent, or in a shower of water or solvent, or under a jet of cleaning gas or steam, such as water vapor.

A cleaning variant may use a vibration cleaning device, in particular to separate dust adhered to the media particles by circulating them on a vibrating screen, or a high frequency vibration cleaning device, such as ultrasound in a bath of cleaning liquid.

It is also necessary to separate the transfer media particles 5 in good condition from those that are worn, broken and can no longer fulfill their function. For this, the passage of the media particles 5 in a screen sieve type vibrating screen or rotating drum is advantageous.

This screening operation can be combined with the cleaning operation of the particles of the transfer media.

Finally any other treatment is possible, such as an incineration operation of organic deposits at very high temperature, or a mixing operation with additives promoting the proper functioning of the device, for example a mixture of media elements with lime which allows of capturing chemical elements present in the fluid, or a heating operation of the transfer media particles 5 in order to reduce the risk of thermal shock that they could undergo when they are reintroduced into the chamber 2. Note that such This heating is not intended to heat the fluid B, but just to attenuate the temperature differences for the media particles 5. The flow rate of the transfer media particles 5 and their reheat temperature thus represents a thermal power of less than 30% of the enthalpy exchange power effected by the device which is the subject of the invention, and can not replace the enthalpy Incipale brought by the fluid A.

According to the invention, it is advantageous to have a special zone of condensation. Indeed, a feature of the invention is to allow the recovery of latent heat. For this, when a hot gas cools below the dew point, it appears a condensation of liquid at the heart of the transfer media.

This condensation causes the production of a quantity of liquid that has to be evacuated from the enclosure. To this end, a condensate collection area is installed in the enclosure.

If condensation occurs in the lower part of the enclosure, the condensing zone consists of a condensate collector connected to a low evacuation.

If the condensation takes place in the upper part of the chamber, as indicated in FIG. 5, ie if the fluid cools while it is rising in the chamber, a specific condensation zone 10 is required. for example in the form of an inclined channel. Thus the fluid that exits the enclosure through the outlet 32 cools in contact with the incoming media through the inlet 51, generates condensates 11 which flow towards the bottom of the channel 12.

Any other collection solution is obviously possible. For example, a collection means as shown in FIG. 6 comprises a sheet of tubes 13 arranged horizontally inside the enclosure 2. These tubes have a closed bottom part and an upper part opened by perforations 14, which are sufficiently small. so that elements of the transfer media 5 can not enter it. The condensates 11 flow vertically, pass through the perforations 14 and are collected by the tubes 13 and discharged through a channel collector 12 which connects the tubes 13 to a general evacuation.

If the collection area does not allow the full recovery of the condensates, some condensates fall back into the main zone where they are revaporized due to the higher temperature prevailing in the area. lower. The vapors are then driven by the rising fluid, cool again, condense and have a new chance of being collected. This results in an increase in the vapor or condensable gas content which increases the condensate flow and the probability for them to be collected and evacuated from the chamber 2. Thus, the solution is effective even if all the condensates are not not captured on the first pass.

The condensation also provides an internal washing function of the media elements. For example, if it is smoke or synthesis gas from a gasification, it is possible to collect dust, ammonia (NH3), hydrochloric acid (HCL), sulfuric acid (SO2) and most volatile organic compounds that are soluble or captured by condensates. The effectiveness of the washing may in certain cases be such that the means of treatment and filtration of the supply media can be greatly reduced. The condensates thus loaded with undesirable elements will require treatment before their evacuation of the process.

According to a variant of the invention, it is advantageous to recycle the condensates. This recycling of treated condensates in the condensing zone allows to dilute the acids and the other pollutants, to stimulate the condensation, to improve the washing of the bringing media, and especially, by the control of the temperature of the condensates recycled, to make evolve the point of dew.

The invention also relates to an enthalpy exchange process using the devices and configurations described above.

In the case of a heat and electricity cogeneration cycle based on a Rankine cycle with steam or any other organic fluid, it is advantageous to use the invention to recover the enthalpy of combustion fumes as a fluid A which is circulated freely in the transfer media, in order to heat and vaporize water as fluid B circulates in a watertight exchanger bathed by the circulating media. All the advantages of the invention are thus obtained.

An additional advantage is that it is thus possible to increase the superheat temperature of the vapor as fluid B, while benefiting from an upper enthalpy range for steam production by recovering a portion of latent heat, and more sensible heat. It is thus possible to obtain an enthalpy supplement greater than 6% with respect to conventional solutions.

As a variant, it is advantageous to preheat the combustion air as fluid C in the case of three stages. This allows better cooling of the transfer media, thus improving the recovery of latent heat by condensation.

In the case of a thermal gasification process, the syngas produced at a temperature which may exceed 1200 ° C. and can advantageously circulate through the invention as fluid A, in order to transmit its enthalpy to various receiving fluids. intended to supply thermal energy to the process, and in particular a step of pyrolysis or thermolysis upstream, for example, by circulating the fluid in a pipe network surrounding the enclosure of the device implemented. It can also heat air or other fluid to reduce the moisture content of the inputs intended to supply the gasification process, for example by means of a heating means. he can finally, transmitting the additional energy to any process external to said gasification process, so that the efficiency of the process is maximized.

In general, the fluid B may be a heat transfer liquid, a thermal oil, a molten salt, a molten metal or water that can be selected according to the required temperature range.

According to a variant of the invention, it is advantageous to have a fluid B as cold as possible in order to capture as much as possible enthalpy of the fluid A. To this end, using a heat pump that processes the fluid B, which leaves the enthalpy exchange device after having sensed the enthalpy of the fluid A, as a hot source, makes it possible on the one hand to extract the enthalpy of the fluid B, to restore it to higher temperature to an auxiliary fluid as a cold source, and also to further cool the fluid A upon return of the cooled fluid B in the enthalpy exchange device 1.

According to a variant of the invention, the exchange of enthalpy is advantageous but not essential for the purpose of carrying out a fluid purification.

Thus, if the fluid A has undesirable elements that it is a question of collecting and separating, the invention is used in the following way: the fluid A flows through the voids of a collection and transfer media . During this crossing, undesirable elements touch the walls of the elements of the media and are captured. When the media is moved to the fluid B action zone, a portion of the unwanted elements are driven with. The fluid B is then used as a cleaning fluid because crossing the media, it will proceed to its washing. The clean media is then returned to the fluid A action zone. According to a variant of the invention, an additional cleaning of the media is performed outside the enclosure 2, during the transfer of the media out of the enclosure 2.

For example, the fluid A is combustion process fumes of biomass in a cogeneration boiler, comprising suspended dusts to be separated. The media is austenitic steel balls coated with a collection agent layer such as water with surfactant added. Fluid B is wash water. The media is injected into the chamber 2 in admixture with the collection agent so that the entire surface of the media is covered. During the circulation of fluid A, the dust is collected and stick to the surface of the balls. When the balls move in the area of action of the fluid B, they cause the dusts which are then washed by the fluid B.

This purification can be improved by triggering the condensation of the water vapor contained in the fluid A. For this purpose, the media is voluntarily cooled below the dew point temperature of the fluid A, or by the fluid B in its zone. action, or by another fluid C in a third zone of action.

According to a variant of the invention, the purification effect improved by the condensation will be further improved by proceeding to the recirculation of a portion of the condensate in the fluid A, after specific cleaning treatment of these condensates. Thus the rate of condensable vapor present in the fluid A is increased and the phenomenon of condensation, thus of purification, will be more intense.

According to another variant of the invention, the collecting agent is a melting agent, such as alkaline salts, which is introduced in admixture with the cold transfer medium. Fluid A is a calorie builder so that the melting agent melts and forms a sticky and collecting layer on the media particles. The fluid B is a gas loaded with undesirable elements which are collected by the surfaces of the media and the fluid B is thus purified during its passage in its zone of action. The media is then evacuated and undergoes a cleaning step.

According to a variant of the invention, the purification of the fluid A may correspond to the following situation: the fluid A is a gas loaded with undesirable chemical elements, such as gaseous sulfurous hydrogen, hypochlorous acid or heavy metals . The media is activated carbon whose role is to capture the unwanted vapors by adsorption, when the fluid A passes through. Then the media is moved in the action zone of a hot fluid B, which will heat the media and ensure the desorption of the adsorbed elements then discharged with the fluid B.

Claims

1- Device (1) for exchange between at least one fluid A and at least one fluid B, comprising an enclosure (2), comprising an outlet (32) of fluid A, a fluid inlet (31), an outlet (42) of fluid B, an inlet (41) of fluid B, characterized in that the position of the fluid inlets and outlets A and B define 2 distinct zones in the chamber, a first fluid action zone A ( 21) between the fluid inlet and outlet A and a second fluid action zone B (22) between the inlet and the fluid outlet B and in that independent solid particles (5) forming a media of mobile transfer are placed in a pile in the chamber (2), in the fluid action zone A (21) and in the fluid action zone B (22) and in that an inlet (51) of said fluid transfer media is placed at one end of the enclosure (2) and that an outlet (52) of said media (52) is placed at the other end of the enclosure (2) and that a transfer means (8) of said transfer medium is interposed between said media outlet (52) and said media inlet (51) providing for loop circulation of said media and further comprising condensate recovery means (10). 2- exchange device according to one of the preceding claims, characterized in that the transfer media has a vacuum rate of at least 20%.

3- exchange device according to one of the preceding claims, characterized in that the independent solid particles (5) are spheres with a diameter of between 3mm and 100mm. 4- exchange device according to one of the preceding claims, characterized in that a flow control means of at least one of the fluids is associated with the inlet and / or the outlet of said fluid.

5. Exchange device according to one of the preceding claims, characterized in that it further comprises a means for cleaning the particles of the transfer medium. 6- exchange device according to one of the preceding claims, characterized in that it further comprises a condensate cleaning means.

7. Exchange device according to one of the preceding claims, characterized in that it further comprises a means of screening the particles of the media ensuring inter alia the elimination of broken or agglomerated elements.

8- exchange device according to one of the preceding claims, characterized in that it comprises at least one sealed heat exchanger (6) placed inside said enclosure in contact with said transfer medium, and connected to said input and at said output of one of said fluids.

9. Exchange device according to one of the preceding claims, characterized in that the independent solid particles constituting the transfer media consist of a thermal conductivity material greater than 0.2 W / mK.

10- Exchange device according to one of the preceding claims, characterized in that the independent solid particles consist of two different materials and in that one of the materials constitutes the outer shell of the particle and the other material is the core of the particle and has a lower melting temperature than the material constituting the outer shell.

11- exchange process, characterized in that it comprises a step of circulating a transfer medium, composed of independent solid particles (5) in a heap in the same chamber, between a first action zone A in which circulates a fluid A and an action zone B in which a fluid B circulates, and in that said transfer medium is returned to the action zone A after having circulated in the action zone B and in that it comprises a step of collecting the condensates formed in contact with one of the fluids and said transfer medium.

12- The exchange process according to the preceding claim, characterized in that the fluid A is hotter than the fluid B.

13- The exchange process according to claim 11, characterized in that the fluid A is less hot than the fluid B.

14- The method of exchange of claim 11, characterized in that the hottest fluid has a temperature above 150 ° C, even more preferably at 400 ° C and quite preferably greater than 600 ° C.

15- exchange process according to one of claims 12 to 14, characterized in that the flow rates of fluids A and B are regulated so that the flow rate of one of the fluids, considered clean, is more than 1% greater than the flow rate of the other fluid, considered dirty, ensuring leakage of the clean fluid to the dirty fluid and preventing the reverse. 16- A method of exchange according to claim 12, characterized in that the fluid A is a hot gas which circulates through the transfer media (5), the fluid B is liquid water and / or steam water flowing in a sealed heat exchanger (6) and the transfer medium flows between the zone A and the zone B, so that the enthalpy of the fluid A is transmitted to the fluid B.

17- The exchange process according to one of claims 12 to 16, characterized in that the fluid A is a gas and in that the fluid B is cooled, after passing over said transfer media, by a heat pump and is then used to condense the condensable vapor contained in the gas A. 18- An exchange process according to one of the claims

12 to 16, characterized in that the transfer medium collects the undesirable elements of the fluid A in the zone A and in that said transfer medium is washed by the fluid B in the zone B.

19- The exchange method according to the preceding claim, characterized in that said transfer medium also circulates in a zone C, in the middle of a fluid C comprising a collector capable of improving the collection capacity of said transfer medium.

20- exchange process according to one of claims 11 to 18 above, characterized in that the condensates provides an internal washing function of the media elements transfer.

21- exchange process characterized in that it implements a device according to one of claims 1 to 10.