Method and apparatus for heat transfer between particulate material and fluid

Abstract

The invention relates to a method for heat transfer between a particulate material (14) capable of forming a moving bed and a fluid (15), comprising: filling a cylindrical chamber (2) with the particulate material (14), the longitudinal axis (XX ') of the chamber extends horizontally in the use configuration of the chamber, supplying fluid to the chamber (2) via at least one cylindrical fluid receiving tube (3) arranged at least partially within the chamber (2), and rotating the chamber (2) about an axis coinciding with its longitudinal axis (XX'). The tube (3) is coaxial with the longitudinal axis (XX ') of the chamber (2) and opens at each end outside the chamber so as to be connectable to a fluid circulation circuit (5), and filling the chamber with particulate material comprises filling to a filling height (H) comprised within a height range defined by the formula: R + a * R1, where R corresponds to the inner radius of the cylindrical chamber (2), and a * R1 corresponds to the outer radius of the cylindrical chamber (2). R1 corresponds to the inner radius of the cylindrical fluid receiving tube (3), and a is between 0 and 1.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method and a device for transferring heat between a particulate material capable of forming a moving bed and a fluid. BACKGROUND

[0002] The present invention relates in particular to a method for transferring heat between a particulate material capable of forming a moving bed and a fluid, said method comprising:

[0003] when the cylindrical chamber is in a configuration called the configuration of use in which the longitudinal axis of said chamber extends horizontally,

[0004] - filling said chamber with a volume of particulate material corresponding to the moving bed to be formed,

[0005] - supplying fluid to the chamber via at least one cylindrical fluid reception tube arranged at least partially inside said chamber, and

[0006] - rotating said chamber around an axis coinciding with the longitudinal axis of the chamber.

[0007] It is noted that here particulate material refers to a collection of non-cohesive particles that mechanically interact. These particles are capable of forming a moving bed under the action of rotation. In other words, the particulate material is considered to be loose.

[0008] Moving bed heat exchangers are known in which heat is transferred between a particulate material and a fluid circulating in at least one tube arranged inside a chamber. Due to the numerous industrial fields in which particulate materials can be used, research into these heat exchangers is increasing. Such heat exchangers can be applied to cool or heat a fluid using a particulate material, or conversely, to cool or heat a particulate material using a fluid. However, the heat exchanger solutions developed to date are costly, have a high energy consumption and are not optimized. SUMMARY

[0009] It is an object of the present invention to propose a heat transfer method and device of the above-mentioned type that is capable of optimal heat transfer between a particulate material and a fluid without adversely affecting the simplicity of the method and device and with a relatively moderate energy requirement.

[0010] To this end, one subject of the invention is a method for transferring heat between a particulate material capable of forming a moving bed and a fluid, said method comprising:

[0011] when the cylindrical chamber is in a configuration called the configuration of use in which the longitudinal axis of said chamber extends horizontally:

[0012] - filling said chamber with a volume of particulate material corresponding to the moving bed to be formed,

[0013] - supplying the chamber with fluid via at least one cylindrical fluid receiving pipe arranged at least partially inside the chamber, and

[0014] - rotating the chamber around an axis coinciding with its longitudinal axis, characterized in that the cylindrical fluid receiving pipe is a fixed pipe coaxial with the longitudinal axis of rotation of the chamber and opens at each of its ends to the outside of the chamber so as to be able to be connected to a fluid circulation circuit, and in that the volume of particulate material used to form a moving bed in the cylindrical chamber corresponds to filling the chamber with particulate material to a filling level comprised in a range of heights defined by the following formula:

[0015] R + a x R1

[0016] where R corresponds to the internal radius of the cylindrical chamber, R1 corresponds to the internal radius of the cylindrical fluid receiving pipe, and a is between 0 and 1, this filling level corresponding to the level of particulate material in the chamber when the particulate material is uniformly distributed throughout the chamber and is leveled.

[0017] It should be noted that filling the chamber with particulate material to a filling level corresponding to the level of particulate material in the chamber means a filling level defined with respect to a horizontal reference plane when the chamber is in the use configuration, i.e. when the longitudinal axis of the chamber is horizontal. This horizontal reference plane is the plane passing through the lowest point of the cylindrical wall of the chamber when the chamber is in the use configuration. This level is measured when the particulate material has been leveled, i.e. under the condition that the upper surface of the particulate material is substantially flat. This leveling of the particulate material uniformly distributed throughout the chamber can simply be achieved by rotating the chamber. It should be noted that the volume of particulate material corresponding to this filling level or level can be determined empirically or by calculation. Indeed, for example, when a is equal to zero and the filling level is equal to the internal radius of the cylindrical chamber, the volume of particulate material used to form a moving bed in the chamber is equal to half the volume of the chamber minus half the volume of the pipe. This pipe is a fixed pipe, that is to say, it remains immobile when the chamber is rotating. It therefore does not rotate with the chamber. The arrangement of the fluid receiving pipe so that it is coaxial with the axis of rotation of the chamber makes it possible, in combination with the predetermined filling level of the chamber, to produce a uniform and dense flow of particles, these particles constituting the particulate material surrounding the fluid receiving pipe, thereby making it possible to optimize the heat transfer between the particulate material and the fluid. This design makes it possible to achieve near-continuous contact between the pipe and at least some of the particulate material while the chamber is rotating. In particular, this design allows the flow of particulate material to circulate on the upper and lower parts of the fluid receiving pipe as the chamber rotates. This optimization of the convection at the surface of the fluid receiving pipe, due to this so-called "double-flow flow" regime of the flow of particulate material, favors the heat transfer. The coaxial arrangement of the pipe inside the chamber also allows the pipe to be constantly fed with fluid while the chamber is rotating. It is clear that the chamber is reclosed before being rotated when it is filled.

[0018] According to one embodiment of the method, the rotation of the chamber around an axis coinciding with its longitudinal axis is performed at an angular velocity between 5 rpm and 50 rpm.

[0019] According to one embodiment of the method, the cylindrical chamber delimited by a cylindrical wall and two end faces is equipped with at least one closable opening formed in the cylindrical wall of the chamber, so as to fill the chamber with particulate material and / or to empty the chamber.

[0020] Preferably, the opening extends from one end face of the chamber to the other end face.

[0021] Another subject of the application is an apparatus for transferring heat between a particulate material capable of forming a moving bed and a fluid, said apparatus comprising: a cylindrical chamber having a use configuration in which its longitudinal axis extends horizontally and in which the chamber is capable of being filled with a volume of particulate material corresponding to the moving bed to be formed; at least one cylindrical fluid reception tube arranged at least partially inside the chamber; and a rotary drive system for rotating the chamber around an axis coinciding with the longitudinal axis of the chamber, characterized in that the fluid reception tube is a fixed tube arranged coaxially with the rotary longitudinal axis of the chamber and opens out to the outside of the chamber at each end of the fluid reception tube so as to be able to be connected to a fluid circulation circuit, and in that the volume of particulate material for forming the moving bed in the cylindrical chamber corresponds to the filling of the chamber with particulate material to a filling height included in the range of heights defined by the following formula:

[0022] R + a x R1, with R corresponding to the internal radius of the cylindrical chamber, R1 corresponding to the internal radius of the cylindrical fluid reception tube, and a being between 0 and 1, this filling height corresponding to the level of the particulate material in the chamber when the particulate material is uniformly distributed throughout the chamber and is leveled. This apparatus is in particular capable of allowing the implementation of the method described above. Again, the arrangement of the fluid reception tube so that it is coaxial with the rotary longitudinal axis of the chamber, combined with the predetermined filling level of the chamber, makes it possible to produce a uniform and dense flow of particles, which constitutes the particulate material surrounding the fluid reception tube, thereby making it possible to optimize the transfer of heat between the particulate material and the fluid. This design makes it possible, when the chamber is rotating, to effectively achieve a nearly constant contact between the tube and at least some of the particulate material. In particular, this design allows the flow of particulate material to circulate on the upper and lower parts of the fluid reception tube as the chamber rotates. Thanks to this state called "double flow" of the flow of particulate material, the convection at the surface of the fluid reception tube is optimized, which favors the transfer of heat.

[0023] According to one embodiment of the application, the ratio of the internal radius of the chamber to the internal radius of the tube is between 3 and 15.

[0024] According to one embodiment of the application, the cylindrical chamber, delimited by a cylindrical wall and by two end faces, is equipped with at least one closable opening formed in the cylindrical wall of said chamber, so as to fill the chamber and / or empty the chamber with granular material. The chamber can be filled uniformly along its entire length. Levelling can be achieved simply by rotating the chamber. Preferably, the opening extends from one end face of the chamber to the other end face.

[0025] According to one embodiment of the application, the device comprises at least one filling station for filling the chamber, said filling station comprising at least one hopper positioned above the chamber when the chamber is in the use configuration, the hopper being mounted so as to be movable along an axis parallel to the longitudinal axis of rotation of the chamber. Once again, this arrangement allows uniform filling of the chamber.

[0026] According to one embodiment of the application, the device comprises a collector of the granular material contained in the chamber, the collector being arranged below the chamber, in vertical alignment with the opening formed in the cylindrical wall of the chamber. This makes the chamber easy to empty.

[0027] According to one embodiment of the application, the rotation drive system for rotating the chamber is configured to rotate the chamber at an angular velocity of between 5 rpm and 50 rpm.

[0028] According to one embodiment of the application, the rotation drive system for rotating the chamber comprises at least one rotating member engaged with the outside of the chamber.

[0029] According to one embodiment of the application, the fluid is a liquid, preferably water. BRIEF DESCRIPTION OF DRAWINGS

[0030] The application will be more clearly understood by reading the following description of exemplary embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:

[0031] Figure 1 a schematic view of a heat transfer device according to the application is depicted;

[0032] Figure 2 a cross-sectional view of the chamber is depicted to show the range of filling height of the chamber;

[0033] Figure 3 a cross-sectional view of the chamber is depicted to show the "double flow flow" regime when the chamber is rotating;

[0034] Figure 4 a partial perspective view of the heat transfer device during a phase of filling of the chamber with granular material is depicted;

[0035] Figure 5 a partial perspective view of the heat transfer device during a phase of emptying of the chamber of granular material is depicted. DETAILED DESCRIPTION

[0036] As mentioned above, the present application relates to a method for transferring heat between a particulate material 14 capable of forming a moving bed and a fluid, and to an apparatus 1 in particular for implementing such a method.

[0037] The particulate material 14 can be any kind of material and originates from the chemical, pharmaceutical, food or some other industry. Figure 2 An example of a particulate material 14 formed by glass beads is shown. Ideally, the size of the particles of the particulate material 14 is between 500 microns and 1 centimeter. The fluid 15 is a liquid, preferably water. Water has good heat storage properties and is low cost.

[0038] As Figure 1 The apparatus 1 shown comprises a cylindrical chamber 2 defined by a cylindrical wall 6 and two end faces 7, in this case each formed by an end plate having a central opening. The cylindrical chamber 2 has a longitudinal axis XX’ formed by the longitudinal axis of the cylinder. As Figure 1 particularly shown in, in use configuration, the longitudinal axis XX’ of the chamber 2 extends horizontally.

[0039] The apparatus 1 further comprises a cylindrical fluid receiving tube 3. The cylindrical tube 3 is arranged at least partially within the chamber 2, so as to be coaxial with the longitudinal axis XX’ of the chamber 2. The cylindrical tube 3 opens at each of its ends to the outside of the chamber 2, or projects beyond the end faces. The openings at each end of the tube 3 are arranged to be flush with or to project beyond the end faces 7 of the chamber 2. At each end of the cylindrical tube 3, the tube 3 is connected to a fluid circulation circuit 5, so as to allow fluid to be received within the tube 3 and to circulate said fluid within the tube 3. To this end, as Figure 1 shown, the fluid circulation circuit 5 can be equipped with a pump. A rotary coupling can be provided between the tube and each end face 7 of the chamber, so that the tube 3 does not rotate, only the chamber rotates around the tube 3. The tube 3 remains fixed.

[0040] In particular, the apparatus 1 further comprises a rotary drive system 4 for rotating the chamber 2 around an axis coinciding with its longitudinal axis XX’. The fluid receiving tube 3 is thus also coaxial with the rotation axis of the chamber 2. This rotary drive system 4 for rotating the chamber 2 comprises at least one rotary member 11 in meshing engagement with the outside of the chamber 2. The rotary member 11 takes here the form of a pinion arranged outside, below the chamber 2. The rotary member 11 engages with a set of teeth on the end face of the chamber, the end plate of which takes the form of a ring gear having circumferential teeth. The teeth form a set of teeth that meshes with the teeth of the pinion.

[0041] The drive system 4 also comprises at least one electric motor 12, which is engaged with the rotating member 11 to drive said rotating member 11 in rotation about an axis parallel to the rotation longitudinal axis XX’ of the chamber 2, and a control unit 13, which controls the electric motor 12.

[0042] In the example described, a drive system 4 is provided having two assemblies constituted by the electric motor / rotating member 11, i.e. one assembly is configured for each end face 7 of the chamber 2, said assemblies operating in synchronism. As a variant, only one assembly can be provided.

[0043] The rotating drive system 4 for rotating the chamber 2 is configured to rotate the chamber 2 at an angular speed between 5 rpm and 50 rpm. The chamber 2 will be filled with a volume of particulate material 14, which corresponds to a filling height H of the chamber 2 filled with particulate material. The height H of the chamber 2 filled with particulate material is measured with respect to the level of the lowest point of the cylindrical wall of the chamber when the chamber is in the use configuration. This height H corresponds to the level of the filling of the chamber with particulate material. Thus, as shown, the height H is measured in the case where the particulate material is evenly distributed in the entire chamber 2, which is flattened. This height H is comprised in the range of heights defined by the formula R + a x R1, where R corresponds to the internal radius of the cylindrical chamber, R1 corresponds to the internal radius of the cylindrical fluid receiving tube 3, and a is between 0 and 1. It should be noted that a can be an integer or a decimal number. The expression “a is between 0 and 1” also includes the possibility for a to take the values 0 and 1. Figure 2

[0044] In other words, the filling height (or filling level) of the chamber 2 is between H1 and H2, where H1 is equal to R and H2 is equal to R + R1.

[0045] Thus, to achieve the “double flow flow” state, the height H is between R and R + R1. When the dimensions of the chamber 2 and of the tube 3 and the size characteristics of the particulate material 14 are known, the volume of particulate material corresponding to this filling height can be determined by calculation, but also empirically, for example by observing the filling. The inventors have noted that outside this range of filling heights, the state is “single flow flow”, i.e. the flow of particulate material is located in the upper part of the tube or in the lower part of the tube, which means that the heat transfer is not optimized.

[0046] In the example described, the chamber 2 has a diameter equal to 40 centimeters. The diameter of the cylindrical fluid receiving tube 3 is equal to 10 centimeters. Ideally, the ratio of the internal radius of the chamber 2 to the internal radius of the tube 3 is between 3 and 15.

[0047] ​In order to enable the cylindrical chamber 2 to be filled and emptied of the granular material 14, the cylindrical chamber 2 is equipped with at least one closable opening 8 formed in the cylindrical wall 6 of said chamber 2. This opening 8 preferably extends from one end face 7 of the chamber 2 to the other end face 7.

[0048] The closing member for closing the opening 8 can be formed by a movable portion of the cylindrical peripheral wall 6 of the chamber 2. This movable portion can take the form of at least one shutter or flap which closes said opening in the closed position. The transition from the closed position of the opening to the open position of the opening can be achieved by sliding and / or pivoting and / or removing said movable portion.

[0049] The device 1 also comprises a filling station for filling the chamber 2. This filling station comprises at least one hopper 9 which is located above the chamber 2 when the chamber 2 is in the use configuration. As Figure 4 indicated, this hopper 9 is mounted so as to be able to move along an axis which is parallel to the longitudinal axis of rotation XX’ of the chamber 2.

[0050] The device also comprises a collector 10 which collects the granular material 14 contained inside the chamber 2. As Figure 5 indicated, this collector 10 is arranged below the chamber 2, in vertical alignment with the opening 8 formed in the cylindrical wall 6 of the chamber 2.

[0051] In practical applications, the chamber 2 is in the use configuration, i.e. its longitudinal axis XX’ extends horizontally. Thus, the opening 8 of the chamber is oriented towards the sky in order to fill the chamber 2 with the granular material 14 and the hopper 9 moves parallel to the longitudinal axis XX’ which forms the axis of rotation of the chamber 2 in order to fill the chamber 2 uniformly, i.e. along the entire length of the chamber 2. Levelling can then be achieved simply by rotating the chamber 2 in order to check whether the filled level or height corresponds to the desired level or height. Thus, as Figure 4 indicated, this filling is performed over the entire length of the chamber 2 thanks to the movement of the hopper 9. Once the filling height H has been reached, the opening 8 of the chamber is closed again. During this filling, the fluid 15 can also be delivered into the fluid receiving pipe 3. Once the chamber 2 has been filled and the chamber 2 has been closed again, the chamber 2 can be rotated and the fluid 15 can circulate along the fluid receiving pipe 3 under the action of the pump equipped in the fluid circulation circuit 5. The heat transfer between the granular material and the fluid can be achieved in a “double flow flow” regime. Temperature control can be performed on the granular material 14 and / or on the fluid 15. For example, when the temperature difference between the temperature of the granular material and the temperature of the fluid is less than a predetermined value, the rotation of the chamber 2 can be stopped.

[0052] Thanks to the relative positioning of the pipe 3 in the chamber 2 and thanks to the filling level of the chamber 2, the heat transfer is optimal, as Figure 3As shown, since the chamber 2 rotates, the heat transfer can occur continuously on the upper and lower portions of the tube 3. As shown Figure 5 As shown, once the heat transfer is completed, the rotation of the chamber 2 is stopped and the chamber 2 is emptied. To this end, the opening 8 of the chamber 2 is oriented towards the ground and opened. The contents of the chamber 2 are poured into a collector 10, which in this case is made in the form of a tray with an open top face, which is arranged below the chamber 2, in vertical alignment with the opening 8 formed in the cylindrical wall of the chamber 2. It can then be envisaged a further filling of the chamber 2 as described above, in order to perform a new operation of heat transfer between loose granular material and fluid 15, each heat transfer operation comprising the filling of the chamber 2 in the use configuration with said granular material, the supply of fluid to the chamber via the cylindrical fluid receiving tube 3 at least partially arranged within the chamber 2, and the rotation of the chamber 2 about its longitudinal axis XX’. This rotation is performed in parallel with the circulation of the fluid within the fluid receiving tube 3.

Claims

1. A method for transferring heat between a particulate material (14) capable of forming a moving bed and a fluid (15), said method comprising: when the cylindrical chamber (2) is in a configuration called in use configuration in which the longitudinal axis (XX') of the chamber (2) extends horizontally: - filling the chamber (2) with a volume of particulate material (14) corresponding to the moving bed to be formed, - supplying the chamber (2) with a fluid via at least one cylindrical fluid receiving tube (3) arranged at least partially inside the chamber (2), and - rotating the chamber (2) around an axis coinciding with its longitudinal axis (XX'), characterized in that the cylindrical fluid receiving tube (3) is a fixed tube (3) coaxial with the rotating longitudinal axis (XX') of the chamber (2) and opens to the outside of the chamber (2) at each of its ends so as to be able to be connected to a fluid circulation circuit (5), and in that the volume of particulate material (14) used to form the moving bed in the cylindrical chamber (2) corresponds to filling the chamber (2) with the particulate material to a filling height (H) comprised in a range of heights defined by the following formula: R + a x R1 where R corresponds to the internal radius of the cylindrical chamber (2), R1 corresponds to the internal radius of the cylindrical fluid receiving tube (3), and a is between 0 and 1, the filling height (H) corresponding to the level of the particulate material (14) in the chamber (2) when the particulate material (14) is uniformly distributed throughout the chamber (2) and is leveled.

2. The heat transfer method according to claim 1, characterized by, The rotation of the chamber (2) around an axis coinciding with its longitudinal axis (XX') is carried out at an angular velocity between 5 rpm and 50 rpm.

3. The heat transfer method according to claim 1 or 2, characterized by, The cylindrical chamber (2) delimited by a cylindrical wall (6) and two end faces (7) is equipped with at least one closable opening (8) formed in the cylindrical wall (6) of the chamber (2) so as to fill the chamber with the particulate material (14) and / or to empty the chamber.

4. The heat transfer method according to claim 3, characterized by The closable opening (8) formed in the cylindrical wall (6) of the chamber (2) extends from one end face (7) to the other end face (7) of the chamber (2). The closable opening (8) formed in the cylindrical wall (6) of the chamber (2) extends from one end face (7) to the other end face (7) of the chamber (2).

5. An apparatus (1) for transferring heat between a particulate material (14) capable of forming a moving bed and a fluid (15), the apparatus (1) comprising: a cylindrical chamber (2) having its longitudinal axis (XX') extending horizontally in a use configuration, and wherein said chamber (2) is able to be filled with a volume of particulate material (14) corresponding to said moving bed to be formed; at least one cylindrical fluid receiving pipe (3) arranged at least partially inside said chamber (2); and a rotary drive system (4) for rotating said chamber (2) around an axis coinciding with the longitudinal axis (XX') of said chamber (2), characterized in that said fluid receiving pipe (3) is a fixed pipe (3) arranged coaxially with the rotary longitudinal axis (XX') of said chamber (2) and opens at each end of said fluid receiving pipe (3) to the outside of said chamber (2) so as to be able to be connected to a fluid circulation circuit (5), and in that the volume of said particulate material (14) used to form said moving bed in said cylindrical chamber (2) corresponds to filling said chamber (2) with said particulate material to a filling height (H) comprised in a range of heights defined by the following formula: R + a x Rl, where R corresponds to the internal radius of said cylindrical chamber (2), Rl corresponds to the internal radius of said cylindrical fluid receiving pipe (3), and a is between 0 and 1, said filling height (H) corresponding to the level of said particulate material (14) in said chamber (2) when said particulate material (14) is uniformly distributed throughout said chamber (2) and is leveled.

6. Heat transfer device (1) according to claim 5, characterized in that The ratio between the internal radius (R) of said chamber (2) and the internal radius (Rl) of said pipe (3) is between 3 and 15.

7. Heat transfer device (1) according to claim 5 or 6, characterized in that Said cylindrical chamber (2), delimited by a cylindrical wall (6) and by two end faces (7), is equipped with at least one closable opening (8) formed in said cylindrical wall (6) of said chamber (2) so as to fill said chamber with said particulate material (14) and / or to empty said chamber.

8. Heat transfer device (1) according to claim 7, characterized in that Said opening (8) extends from one end face (7) to the other end face (7) of said chamber (2).

9. Heat transfer device (1) according to any one of claims 5 to 8, characterized in that Said device (1) comprises at least one filling station for filling said chamber (2), said filling station comprising at least one hopper (9) positioned above said chamber (2) when said chamber (2) is in said use configuration, said hopper (9) being mounted so as to be able to move along an axis parallel to the rotary longitudinal axis (XX') of said chamber (2).

10. Heat transfer device (1) according to claim 7 or 8, characterized in that Said device comprises a collector (10) of said particulate material (14) contained in said chamber (2), said collector (10) being arranged below said chamber (2) in vertical alignment with said opening (8) formed in said cylindrical wall (6) of said chamber (2).

11. Heat transfer device (1) according to any one of claims 5 to 10, characterized in that Said rotary drive system (4) for rotating said chamber (2) is configured to rotate said chamber (2) at an angular velocity between 5 rpm and 50 rpm.

12. Heat transfer device (1) according to any one of claims 5 to 11, characterized in that Said rotary drive system (4) for rotating said chamber (2) comprises at least one rotary member (11) engaged with the outside of said chamber (2).

13. Heat transfer device (1) according to any one of claims 5 to 12, characterized in that Said fluid (15) is a liquid, preferably water.

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