The present invention relates bringing a gas and a liquid into contact in an enclosure, the gas and the liquid circulating in the enclosure in the same direction in the form of a gas stream and a liquid stream, respectively.
In the industrial, service or household field, there are a large number of applications in which it proves necessary to bring a gas and a liquid into contact. For example, in a non limiting and non-exhaustive manner, one application consists in bringing a gas into contact with a liquid in order to effect a heat exchange between the gas and the fluid, for example to cool the gas (in particular combustion gases, industrial fumes, etc.) or on the contrary to heat the gas using the liquid, or vice versa to heat the liquid or to cool it using the gas. Another application consists in bringing a gas into contact with a liquid in order to humidify or dehumidify the gas stream. Another application consists in bringing a gas into contact with a liquid in order to clean up or filter the gas stream, in particular by trapping certain pollutants or certain molecules of the gas in the liquid. The aforementioned applications can of course be combined with one another.
Various technical solutions for bringing a gas and a liquid into contact have therefore been proposed to date.
Among these known technical solutions, a first solution may be mentioned, which is described in international patent applications WO2015/086979 and WO2016/071648 by the applicant, and which consists in passing the gas stream directly through a volume of the liquid contained in an enclosure, by injecting the gas stream into the volume of liquid, below the surface of this volume of liquid. This technical solution has the particular advantage of making it possible to achieve high energy yields for the heat exchange between the liquid and the gas by using the thermal conductivity and the latent heat of the liquid. However, it has the drawback of requiring the use of high-power fans or compressors to inject the gas stream into the volume of liquid because of the significant pressure drop caused by this volume of liquid on the path of the gaseous flow.
A second technical solution consists in passing the gas stream through a curtain of fine droplets of the liquid or through an exchange surface permeable to the gas and containing the liquid, for example a textile material imbibed with water. The main drawback of this type of solution lies in the very low energy yield of the heat exchange between the liquid and the gas stream, which detrimentally requires the use of very large and bulky exchange surfaces. The same is true for gas filtering applications, which require the use of very large and bulky contact surfaces between the gas and the liquid.
A third known technical solution consists in circulating in a vertical exchange enclosure of the tower type, in opposite directions and in contact with one another, an ascending gas stream and a liquid stream descending by gravity in the enclosure. This third technical solution has the advantage of requiring the implementation, for the forced circulation of the ascending gas stream, of fans or compressors which are generally of lower power than for the first aforementioned solution, because the pressure drop on the path of the gas stream is low. On the other hand, like for the aforementioned second solution, the energy efficiency of the heat exchange between the liquid and the gas is lower than for the first solution, which in practice requires the use of exchange enclosures of very large height in order to sufficiently increase the contact duration between the gas and the liquid. The same is true with this third solution for gas filtering applications using liquid.
The present invention aims to provide a new technical solution for bringing a gas and a liquid into contact.
More particularly, this new technical solution makes it possible to improve the efficiency of the contact between the gas and the liquid compared to the second and third solutions mentioned above.
More particularly, this new technical solution makes it possible to obtain a pressure drop on the path of the gas stream which may be less than the first technical solution mentioned above.
The invention thus relates to a device for bringing a gas and a liquid into contact comprising an enclosure, first means for introducing into said enclosure and circulating therein a gas stream, second means for introducing into said enclosure and circulating therein a liquid stream that circulates inside the enclosure in the same direction as the gas stream, and means for mixing the gas stream and the liquid stream, which are positioned inside the enclosure in the path of the gas stream and liquid stream and which are capable of locally deflecting upward, and/or of locally causing to rise, at least one portion of the gas stream and liquid stream, so as to locally create turbulences in the gas stream and in the liquid stream.
In the context of the invention, the directions of circulation of the gas stream and of the liquid stream being the same, the invention can advantageously be easily implemented with extremely varied working pressures, and unlike the aforementioned solutions of the prior art, can advantageously be implemented easily in particular with high working pressures above atmospheric pressure.
More specifically, the device constituting the invention may comprise the following additional and optional features, taken in isolation, or in combination with each other:
Another object of the invention is a method for bringing a gas into contact with a liquid by means of the aforementioned device, in which a stream of said gas and a stream of said liquid are introduced, preferably continuously, into the vertical enclosure upstream from the mixing means.
Another object of the invention is the use of the aforementioned device for bringing a gas and a liquid into contact.
The features and advantages of the invention will become apparent from reading the detailed description below of several particular embodiments of the invention, which particular embodiments are described as non-limiting and non-exhaustive examples of the invention, and with reference to the accompanying drawings in which:
This device 1 comprises an enclosure E, which in this particular example and in a non-limiting manner with respect to the invention, comprises a first vertical portion 2 of central vertical axis 2a and of height H, which communicates in the bottom with a second horizontal portion 3 of length L.
Referring to
The enclosure 2 comprises, in the bottom, a lower opening 20b which allows it to communicate with the horizontal enclosure 3.
In the variant of
The first vertical portion 2 of the enclosure E is equipped with an intake conduit 23, with central axis 23c which passes through the side wall 20 of the enclosure 2.
This intake conduit 23 comprises, outside the enclosure E, an intake opening 23a for a descending liquid stream L and inside the first vertical portion 2 of the enclosure E, an opening 23b for the introduction into the enclosure 2 of the descending liquid stream L.
Preferably, but in a non-limiting manner with respect to the invention, the axis 23c of the conduit is inclined with respect to the vertical by an angle substantially equal to 45°; the opening 23b for introducing the descending liquid stream L into the enclosure 2 is positioned substantially at or near the central vertical axis 2a of the first vertical portion 2 of the enclosure E.
The enclosure E is also equipped with static mixing means 4A, which are positioned inside the first vertical portion 2 of the enclosure E, on the path of the descending gas stream G and of the descending liquid stream L, downstream of the gas inlet opening 20a and of the liquid inlet opening 23b.
In this particular embodiment, these mixing means 4A comprise mixing elements 40A, in the form of curved plates, which are fixed to the side wall 20 of the first vertical portion 2 of the enclosure E. Each plate 40A has a curvature, in this case and in a non limiting manner with respect to the invention in the form of an arc of a circle, which makes it possible to locally deflect upward at least one portion of the descending gas stream and of the descending liquid stream, so as to locally create turbulences T1, T2, T3 (
More particularly, each curved plate 40A comprises a concave upper face 40c. Each curved plate 40A is fixed at or in the vicinity of one 40a of its edges to the side wall 20 of the first vertical portion 2 of the enclosure E, and has a free edge 40b, opposite the wall 20, which is located at a level lower than the fixing edge 40a of the plate 40A, but at a level slightly higher than the lowest point of the curved upper face 40c of the plate 40A.
This free edge 40b is spaced from the side wall of the first vertical portion 2 of the enclosure E, which makes it possible to provide a space, between this free edge and said side wall, allowing the downward passage of the descending gas stream and of the descending liquid stream.
Preferably, but in a non limiting manner with respect to the invention, the free edge 40b of each plate 40A is positioned substantially at or near the central vertical axis 2a of the first vertical portion 2 of the enclosure E.
The curved plates 40A are fixed inside the first vertical portion 2 of the enclosure E, while being spaced apart from each other in the vertical direction and preferably being spaced apart from each other in the horizontal direction, more preferably and as illustrated in
In the particular embodiment of
With reference to
In a less efficient alternative embodiment, the device could only comprise this uppermost first plate 40A.
The second horizontal portion 3 of the enclosure E, with horizontal central axis 3a, comprises an upper wall 30 in which an opening 30a is formed which coincides with the lower opening 20b of the first vertical portion 2 of the enclosure E, and which allows the two parts 2 and 3 to communicate with each other.
In its extreme part furthest from the first vertical portion 2 of the enclosure E, the second horizontal portion 3 of the enclosure E comprises a lower discharge opening 30b for the discharge at least by gravity of the liquid at the outlet of the enclosure E and an upper discharge opening 30c for the discharge of gas at the outlet of the enclosure E. The liquid discharge opening 30b communicates with a lower vertical discharge conduit 31 and the gas discharge opening 30c communicates with an upper vertical discharge conduit 32.
The second horizontal portion 3 of the enclosure E further comprises a manual emptying opening 33, which, during the operation of the device 1, is temporarily closed by means of a removable plug, and which can be opened to perform manual emptying by gravity of the liquid remaining in the device 1 at the end of operation.
The second horizontal portion 3 of the enclosure E also comprises, at the top, a discharge conduit 34 which makes it possible to control the level of liquid in the horizontal enclosure 3, and if necessary to discharge a surplus of liquid when the liquid level reached in the second horizontal portion 3 of the enclosure E is too high.
Inside the second horizontal portion 3 of the enclosure E, the device comprises two lower vertical internal walls 35, which are spaced apart in the horizontal direction, and which define three successive internal chambers 37 along the second horizontal portion 3 of the enclosure E. The free upper edge 35a of each lower vertical internal wall 35 is spaced apart from the upper wall 30 of the second horizontal portion 3 of the enclosure E, so as to provide, between this upper wall 30 and said free upper edge 35a, a passage making it possible to make two neighboring enclosures communicate with each other 37.
In order to force the gas to mix with the liquid as it passes through the horizontal enclosure 3 and to prevent premature separation of the gas and the liquid in the upstream part of the second horizontal portion 3 of the enclosure E in the region of the first vertical portion 2 of the enclosure E, the device also comprises an upper internal wall 36, which is positioned between the two lower vertical internal walls 35. The free lower edge 36a of this upper vertical internal wall 36 is spaced apart from the lower wall 30′ of the second horizontal portion 3 of the enclosure E, so as to provide a passage between this lower wall 30′ and said lower edge 36a.
The free lower edge 36a of this upper vertical internal wall 36 is preferably located below the level of the free upper edges 35a of the lower vertical internal walls 35.
Referring to
The intake conduit 23 is connected to a pump 6, which makes it possible to introduce a descending liquid stream L continuously, upstream from the mixing means 4A, inside the enclosure E, preferably with an adjustable flow rate. This pump 6 makes it possible to circulate said liquid stream L in the same circulation direction as the gas stream G, between the liquid intake opening 3b and the liquid discharge opening 30b.
Initially, the second horizontal portion 3 of the enclosure E is pre-filled with a liquid level N (
During operation, the fan or compressor 5 and the pump 6 being on, at the outlet 23b of the intake conduit 23, a descending liquid stream L is projected against the curved upper face 40c of the uppermost first plate 40A and is at least partially deflected upward. At least one portion of the descending gas stream G in contact with this uppermost first plate 40A is also locally deflected upward. This results in the formation locally at this uppermost first plate 40A of a turbulence T1 which advantageously allows mixing and a more intimate blend of gas and liquid.
The liquid stream flowing downward by gravity in the first vertical portion 2 of the enclosure E and the gas stream being forced to descend inside the first vertical portion 2 of the enclosure E by the fan or compressor 5, the gas stream and the liquid stream descend into the enclosure to the next curved plate 40A, and the same phenomena of upward deflection of gas and liquid with formation of turbulence T2, T3 occur at the other curved plates 40A.
At the outlet of the first vertical portion 2 of the enclosure E, a first intimate blend of the gas stream G and the liquid stream L is thus obtained. The presence on the path of the gas and liquid streams of the curved plates 40A creating the turbulences T1, T2, T3 advantageously makes it possible to improve the efficiency of this blending and thus to reduce the height H of the first vertical portion 2 of the enclosure E. In addition, the pressure drop created on the path of the gas stream G by the curved plates 40A is low, which makes it possible to avoid oversizing the fan or compressor 5.
After they pass through the first vertical portion of the enclosure E, the liquid stream and the gas stream descend into the second horizontal portion 3 of the enclosure E, passing through the openings 20b, 30a.
During operation, the liquid flows in the horizontal enclosure 3 as far as the liquid discharge opening 30b, which continuously renews the liquid contained in the enclosure; the upper vertical internal wall 36 obstructs the passage of gas and forces the gas stream to pass through the volume of liquid contained in the second horizontal portion 3 of the enclosure E, which makes it possible to obtain additional contact between the gas and the liquid.
The separation of the gas and the liquid takes place in the downstream end portion of the second horizontal portion 3 of the enclosure E, opposite the first vertical portion 2 of the enclosure E, the gas stream after contact with liquid being discharged from the enclosure E through the upper discharge opening 30c and the liquid being discharged from the enclosure E through the lower discharge opening 30b.
In another variant embodiment of the invention, the device could only comprise a vertical portion 2 and could be devoid of a horizontal portion 3, the gas discharge opening and the liquid discharge opening in this case for example being provided in said vertical portion 2.
The plates 40A can be replaced by any equivalent mixing means fulfilling the function of locally deflecting upward and/or of locally raising at least one portion of the descending gas stream and the descending liquid stream, so as to locally create turbulence in the descending gas stream and in the descending liquid stream, while allowing the downward passage of the descending gas stream and the descending liquid stream.
For example and in a non-exhaustive manner, the mixing means may comprise paddle wheels which are positioned inside the enclosure, on the path of the descending gas stream and of the descending liquid stream, and which are suitable, when they are rotated, for causing at least one portion of the descending gas stream and the descending liquid stream to rise locally, so as to locally create turbulences in the descending gas stream and in the descending liquid stream. These paddle wheels or the like can also be combined with curved plates 40A.
In the variant embodiment of
Preferably as illustrated, each internal blade 40B is a flat semi-cylindrical wall, which extends from the cylindrical internal wall 41 of the drumup to substantially the central rotating shaft 42 and which more particularly is inclined downward.
More particularly, the internal blades 40B are vertically and horizontally spaced apart.
During operation, the rotary drum 41 equipped with the internal blades 40B is driven in rotation (
The descending liquid stream L and the descending gas stream G flow in the same direction downward in successive contact with the rotating internal blades 40B. Under the effect of their rotation, each rotating internal blade 40B causes at least one portion of the gas stream and the liquid stream to rise locally, so as to locally create successive turbulences T1 to T8 in the gas stream and in the liquid stream.
An intimate blend of the gas stream G and the liquid stream L is thus obtained at the outlet of the vertical portion 2 of the enclosure E. The presence on the path of the gas and liquid streams of the rotating internal blades 40B creating the turbulences T1 to T8 advantageously makes it possible to improve the efficiency of this blending and thus to reduce the height of the first vertical portion 2 of the enclosure E. In addition, the pressure drop created on the path of the gas stream G by the rotating internal blades 40B is low, which makes it possible to avoid oversizing the fan or compressor.
After their passage through the first vertical portion of the enclosure E, the liquid stream L and the gas stream G descend into the second horizontal portion 3 of the enclosure E and are discharged respectively through the discharge openings 30b and 30c.
The variant of
During operation, and in a manner comparable to the variant of
The descending liquid stream L and the descending gas stream G flow in the same direction downward in successive contact with the rotating internal plates 40C. Under the effect of their rotation, each rotating internal plate 40C causes at least one portion of the gas stream and the liquid stream to rise locally, so as to locally create successive turbulences T1 to T5 in the gas stream and in the liquid stream. An intimate blend of the gas stream G and the liquid stream L is thus obtained at the outlet of the vertical portion 2 of the enclosure E
The previously described variants of
The second variant of
In the variant of
During operation, the rotary drum 41 equipped with the radial internal blades 40D is driven in rotation by motorization means at a controlled speed and the liquid stream and the gas stream are introduced into the enclosure E upstream from the mixing means 4D owing to the implementation of a fan or compressor (not shown in
In the context of the invention, the rotary drum can be replaced by any rotating mixing means positioned inside the enclosure E in the path of the gas stream G and the liquid stream L and which is capable of locally deflecting upward, and/or of locally causing to rise, at least one portion of the gas stream and the liquid stream, so as to locally create turbulences in the gas stream and in the liquid stream. The rotary drum can for example be replaced by a rotating screw fulfilling the same mixing function
The device of the invention can be used in all technical fields where it is useful to bring a gas stream G into contact with a liquid stream.
The liquid can be of any type and can, for example, but not necessarily, be water or an acidic, a neutral or a basic solution.
By way of non-limiting and non-exhaustive examples of application, The device of the invention can for example be used in the following applications, which applications can be combined if necessary:
Number | Date | Country | Kind |
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1857446 | Aug 2018 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2019/069716 | 7/22/2019 | WO | 00 |