Method and equipment for heat transfer between granular material and fluid

Abstract

A method for heat transfer between a granular material (14) capable of forming a movable bed and a fluid (15), the method comprising: filling a cylindrical chamber (2) with the granular material (14) having a longitudinal axis (XX') extending horizontally in a working state; supplying the fluid to the chamber (2) through at least one cylindrical fluid receiving tube (3) which is at least partially located inside the chamber (2); and rotating the chamber (2) about an axis coinciding with the longitudinal axis (XX') of the chamber (2). The tube (3) is coaxial with the longitudinal axis (XX') of the chamber (2) and has both ends opening to the outside of the chamber (2) so as to be connectable to a fluid circulation circuit (5). Filling the chamber (2) with the granular material (14) includes filling to a filling height (H) within a range of heights defined by the formula: R + a × R1. In the equation, R corresponds to the inner 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 heat transfer method and equipment between a granular material capable of forming a moving bed and a fluid.

[0002] The present invention particularly relates to a heat transfer method between a granular material capable of forming a moving bed and a fluid, the method including the following: When the cylindrical chamber is in a configuration referred to as a use state where the longitudinal axis of the chamber extends horizontally, · filling the chamber with a volume of granular material corresponding to the moving bed to be formed, · supplying fluid to the chamber through at least one cylindrical fluid inlet pipe at least partially disposed inside the chamber, and · rotating the chamber about an axis coinciding with the longitudinal axis of the chamber.

[0003] It should be noted that in this specification, the granular material means an aggregate of non-cohesive particles that interact mechanically. These particles can form a moving bed under the action of rotation. In other words, this granular material can be said to be in a loose state.

[0004] Moving bed heat exchangers in which heat is transferred between a granular material and a fluid circulating in at least one pipe disposed inside a chamber are known. These heat exchangers are being increasingly studied because of the large number of industries that may use granular materials. Such heat exchangers can find applications for cooling or heating a fluid from a granular material, or conversely, cooling or heating a granular material from a fluid. However, the heat exchanger solutions developed so far are expensive, consume a large amount of energy, and are not optimized.

[0005] One object of the present invention is to propose a heat transfer method and equipment of the aforementioned type that enable optimal heat transfer between a granular material and a fluid without adversely affecting the simplicity of the method and equipment and with the equipment having a relatively moderate energy requirement.

[0006] For this purpose, one subject of the present invention is a method for heat transfer between a granular material capable of forming a movable bed and a fluid, the method being When a cylindrical chamber is in a configuration referred to as a "usage state" in which the longitudinal axis of the chamber extends horizontally, - Fill the chamber with granular material in a volume corresponding to the moving bed to be formed. - At least a portion of the fluid is supplied to the chamber via at least one cylindrical fluid receiving tube located inside the chamber, and - Rotating the chamber around an axis that coincides with the longitudinal axis of the chamber. Includes, The cylindrical fluid receiving tube is a fixed tube coaxial with the longitudinal axis of rotation of the chamber, and both ends are open to the outside of the chamber so that it can be connected to a fluid circulation circuit, and, The volume of granular material used to form a moving bed within a cylindrical chamber corresponds to filling the chamber with granular material up to a filling height within the height range defined by the formula: R + a × R1. In the formula, R corresponds to the inner radius of the cylindrical chamber, R1 corresponds to the inner radius of the cylindrical fluid receiving tube, and a is between 0 and 1. This packing height corresponds to the level of granular material in the chamber when the granular material is evenly distributed throughout the chamber and flattened.

[0007] It should be noted that when a chamber is filled with granular material up to a filling height corresponding to the level of granular material within the chamber, the filling height is defined relative to a horizontal reference plane when the chamber is in use, 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 use. This level is measured when the granular material is at the same height, i.e., when the top surface of the granular material is substantially flat. This leveling of the granular material, which is evenly distributed throughout the chamber, can be achieved simply by rotating the chamber. It should be noted that the volume of granular material corresponding to this filling height or level can be determined empirically or by calculation. In practice, for example, when a is equal to 0 and the filling height is equal to the inner radius of the cylindrical chamber, the volume of granular material that helps form a moving bed in the chamber is equal to half the volume of the chamber minus half the volume of the tube. The tube is a fixed tube, i.e., it remains stationary while the chamber is rotating. Therefore, this tube does not rotate together with the chamber. By positioning the fluid receiving tube coaxially with the chamber's axis of rotation, and in combination with the chamber's predefined filling level, it is possible to create a uniform and dense flow of particles constituting the granular material around the fluid receiving tube, thereby optimizing heat transfer between the granular material and the fluid. This design effectively enables nearly permanent contact between the tube and at least some of the granular material as the chamber rotates. In particular, this design allows the flow of granular material to circulate both above and below the fluid receiving tube as the chamber rotates. Thanks to this behavior of the granular material flow, referred to as "double flow," convection at the surface of the fluid receiving tube is optimized, and this optimization is beneficial for heat transfer. The coaxial arrangement of the tube inside the chamber also allows for a continuous supply of fluid to the tube in parallel with the chamber's rotation. Naturally, the chamber is closed again before rotation once it is filled.

[0008] According to one embodiment of this method, the rotation of the chamber about an axis coinciding with the longitudinal axis of the chamber is performed at an angular velocity between 5 and 50 rpm.

[0009] According to one embodiment of the present method, a cylindrical chamber bounded by a cylindrical wall and two end faces is provided with at least one plugged opening formed in the cylindrical wall of the chamber for filling and / or discharging granular material.

[0010] Preferably, this opening extends from one end face of the chamber to the other end face.

[0011] Another subject of the present invention is a granular material capable of forming a moving bed and equipment for heat transfer between the granular material and a fluid. The equipment includes a cylindrical chamber (in operation, the longitudinal axis of the chamber extends horizontally, and the chamber can be filled with granular material in a volume corresponding to the moving bed to be formed), at least one cylindrical fluid receiving tube at least partially located inside the chamber, and a rotational drive system for rotating the chamber about an axis coincident with the longitudinal axis of the chamber, wherein the fluid receiving tube is a fixed tube positioned coaxially with the longitudinal axis of rotation of the chamber, and both ends open to the outside of the chamber so as to be connectable to a fluid circulation circuit, and the volume of granular material for forming the moving bed in the cylindrical chamber corresponds to filling the chamber with granular material to a filling height within the range of heights defined by the formula: R + a × R1, where R corresponds to the inner radius of the cylindrical chamber, R1 corresponds to the inner radius of the cylindrical fluid receiving tube, and a is between 0 and 1. This filling height corresponds to the level of granular material in the chamber when it is evenly distributed and flattened throughout the chamber. This equipment can enable the implementation of the method described above. Again, positioning the fluid receiving tube coaxial with the longitudinal axis of rotation of the chamber, in combination with the predefined filling level of the chamber, makes it possible to create a uniform and dense flow of particles constituting the granular material around the fluid receiving tube, thereby optimizing heat transfer between the granular material and the fluid. This design effectively enables nearly permanent contact between the tube and at least some of the granular material as the chamber rotates. In particular, this design allows the flow of granular material to circulate both above and below the fluid receiving tube as the chamber rotates. Thanks to this behavior of the granular material flow, referred to as "double flow," convection at the surface of the fluid receiving tube is optimized, and this optimization is beneficial for heat transfer.

[0012] According to one embodiment of the present invention, the ratio of the inner radius of the chamber to the inner radius of the tube is between 3 and 15.

[0013] According to one embodiment of the present invention, a cylindrical chamber bounded by a cylindrical wall and two end faces comprises at least one plugged opening formed in the cylindrical wall of the chamber for filling and / or discharging granular material. The chamber can be filled uniformly along its entire length. Flattening can be achieved simply by rotating the chamber. Preferably, the opening extends from one end face to the other end face of the chamber.

[0014] According to one embodiment of the present invention, the apparatus includes at least one filling station for filling a chamber, the station including at least one hopper positioned above the chamber when the chamber is in use, the hopper being mounted to move along an axis parallel to the longitudinal axis of rotation of the chamber. Again, this arrangement enables uniform filling of the chamber.

[0015] According to one embodiment of the present invention, the apparatus includes a collector for granular material contained within a chamber, which is positioned below the chamber on a vertical line through an opening formed in the cylindrical wall of the chamber. This facilitates the discharge of the chamber.

[0016] According to one embodiment of the present invention, a rotary drive system for rotating a chamber is configured to rotate the chamber at an angular velocity between 5 and 50 rpm.

[0017] According to one embodiment of the present invention, a rotary drive system for rotating a chamber includes at least one rotating member that meshes and engages with the outer portion of the chamber.

[0018] According to one embodiment of the present invention, the fluid is a liquid, preferably water. [Brief explanation of the drawing]

[0019] The present invention will be clearly understood by referring to the accompanying drawings and reading the following description of exemplary embodiments.

[0020] [Figure 1] Figure 1 shows a schematic view of the heat transfer equipment according to the present invention.

[0021] [Figure 2] Figure 2 shows a cross-sectional view of the chamber to show the range of the filling height of the chamber.

[0022] [Figure 3] Figure 3 shows a cross-sectional view of the rotating chamber to show the behavior of the "double flow".

[0023] [Figure 4] Figure 4 shows a partial perspective view of the heat transfer equipment at the stage of filling the chamber with granular material.

[0024] [Figure 5] Figure 5 shows a partial perspective view of the heat transfer equipment at the stage of discharging the granular material from the chamber.

[0025] As mentioned above, the present invention relates to a heat transfer method between a granular material 14 capable of forming a moving bed and a fluid, and particularly to equipment 1 for implementing the method.

[0026] The granular material 14 can be of any kind and can be derived from chemistry, pharmacy, food or other industries. Figure 2 shows an example of the granular material 14 formed from glass beads. Ideally, the particle size of the granular material 14 is between 500 microns and 1 cm. The fluid 15 is a liquid, preferably water. Water provides good heat storage characteristics and is low in cost.

[0027] The equipment 1 shown in Figure 1 includes a cylindrical chamber 2 bounded by a cylindrical wall 6 and two end faces 7, and in this example, each is formed by an end plate having a central opening. This cylindrical chamber 2 has a longitudinal axis XX' formed by the longitudinal axis of the cylinder. In the operating state, the longitudinal axis XX' of the chamber 2 extends horizontally, particularly as shown in Figure 1.

[0028] Equipment 1 further includes a cylindrical fluid receiving tube 3. This cylindrical tube 3 is at least partially located inside the chamber 2 so as to be coaxial with the longitudinal axis XX' of the chamber 2. The cylindrical tube 3 opens to the outside of the chamber 2 at both ends or protrudes beyond the end faces. The openings at both ends of the tube 3 are positioned at the same height as the end faces 7 of the chamber 2 or protrude beyond the end faces. At both ends, the cylindrical tube 3 is connected to a fluid circulation circuit 5 to allow fluid to be received into the tube 3 and to allow the fluid to be circulated inside the tube 3. For this purpose, the fluid circulation circuit 5 may include a pump as shown in Figure 1. A swivel joint may be provided between the tube and each end face 7 so that the tube 3 does not rotate and only the chamber rotates around the tube 3. The tube 3 remains fixed.

[0029] Specifically, the apparatus 1 further includes a rotational drive system 4 for rotating the chamber 2 about an axis that coincides with the longitudinal axis XX' of the chamber 2. Therefore, the fluid receiving pipe 3 is also coaxial with the rotation axis of the chamber 2. This rotational drive system 4 for rotating the chamber 2 includes at least one rotating member 11 that meshes and engages with the outer portion of the chamber 2. This rotating member 11 takes the form of a pinion located on the outside and below the chamber 2. This rotating member 11 meshes with a toothed row on the end face of the chamber. The end face plate takes the form of a ring gear having circumferential teeth. These teeth form a toothed row that meshes with the teeth of the pinion.

[0030] The drive system 4 further includes at least one electric motor 12 that engages with the rotating member 11 to drive the rotation of the rotating member 11 about an axis parallel to the longitudinal axis XX' of rotation of the chamber 2, and a control unit 13 that controls the electric motor 12.

[0031] In the example shown, a drive system 4 is provided, having two assemblies consisting of motor / rotating members 11, i.e., one assembly per end face 7 of the chamber 2, and the assemblies operate synchronously. In a variation, only one assembly may be provided.

[0032] The rotary drive system 4 for rotating the chamber 2 is configured to rotate the chamber 2 at an angular velocity between 5 and 50 rpm. The chamber 2 is intended to be filled with granular material 14 in a volume corresponding to the filling height H to which the chamber 2 is filled with granular material. This height H to which the chamber 2 is filled with granular material is measured relative to a horizontal plane passing through the lowest point of the cylindrical wall of the chamber when the chamber is in use. This height H corresponds to the level to which the chamber is filled with granular material. Thus, this height H is measured when the granular material, uniformly distributed throughout the chamber 2, is flattened, as shown in Figure 2. This height H is within the range of heights defined by the formula R + a × R1, where R corresponds to the inner radius of the cylindrical chamber, R1 corresponds to the inner radius of the cylindrical fluid receiving tube 3, and a is between 0 and 1. It should be noted that a may be an integer or a decimal. The expression "a is between 0 and 1" includes the possibility that a chooses values ​​0 and 1.

[0033] In other words, the filling height (or filling level) of chamber 2 is between H1 and H2, where H1 is equal to R and H2 is equal to R + R1.

[0034] Therefore, the height H lies between R and R+R1 in order to achieve “double flow” behavior. The volume of granular material corresponding to this filling height can be determined by calculation if the dimensions of the chamber 2 and tube 3 and the dimensional characteristics of the granular material 14 are known, but it may also be determined empirically, for example, by observing the filling. The inventors have noted that outside this range of filling height, the behavior is “single flow,” meaning that the flow of granular material is located at the top or bottom of the tube and heat transfer is not optimized.

[0035] In the example shown, chamber 2 has a diameter equal to 40 cm. The cylindrical fluid receiving tube 3 has a diameter equal to 10 cm. Ideally, the ratio of the inner radius of chamber 2 to the inner radius of tube 3 is between 3 and 15.

[0036] To enable filling the chamber 2 with granular material 14 and discharging the granular material 14, the cylindrical chamber 2 is provided with at least one plugged opening 8 formed in the cylindrical wall 6 of the chamber 2. This opening 8 preferably extends from one end face 7 to the other end face 7 of the chamber 2.

[0037] A plug member for closing this opening 8 may be formed by a movable portion of the cylindrical peripheral wall 6 of the chamber 2. This movable portion may take the form of at least one flap or shutter that closes the opening in the closed position. The transition of the opening from the closed position to the open position may be achieved by sliding and / or pivoting and / or removing the movable portion.

[0038] Equipment 1 also includes a filling station for filling chamber 2. This station includes at least one hopper 9 located above chamber 2 when chamber 2 is in use. This hopper 9 is mounted to be movable along an axis parallel to the longitudinal axis XX' of rotation of chamber 2, as shown in Figure 4.

[0039] The apparatus also includes a collector 10 for the granular material 14 contained within the chamber 2. As shown in Figure 5, the collector 10 is positioned below the chamber 2, aligned perpendicularly with an opening 8 formed in the cylindrical wall 6 of the chamber 2.

[0040] In practice, the chamber 2 is in use, i.e., its longitudinal axis XX' extends horizontally. Therefore, the opening 8 of the chamber is oriented upward to fill the chamber 2 with granular material 14, and the hopper 9 moves parallel to the longitudinal axis XX' that forms the axis of rotation of the chamber 2 in order to fill the chamber 2 evenly, i.e., along the entire length of the chamber 2. Flattening can then be easily achieved by rotating the chamber 2 to ensure that the filling level or height matches the desired one. Thus, this filling is carried out along the entire length of the chamber 2 thanks to the movement of the hopper 9, as shown in Figure 4. Once the filling height H is reached, the opening 8 of the chamber is closed again. During this filling, the fluid 15 may also be introduced into the fluid receiving pipe 3. Once the filling of the chamber 2 is completed and the chamber 2 is 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 provided by the fluid circulation circuit 5. Heat transfer between the granular material and the fluid can be achieved under "double flow" behavior. Temperature control can be performed with the granular material 14 and / or fluid 15. The rotation of the chamber 2 can be stopped, 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.

[0041] Due to the relative position of the tube 3 within the chamber 2 and the filling level of the chamber 2, heat transfer is optimal as shown in Figure 3. This is because heat transfer can occur continuously across the upper and lower parts of the tube 3 as the chamber 2 rotates. Once heat transfer is complete, the rotation of the chamber 2 is stopped and the chamber 2 is emptied as shown in Figure 5. To do this, the opening 8 of the chamber 2 is opened toward the ground. The contents of the chamber 2 are discharged into a collector 10, which in this example is manufactured in the form of a tray with an open top. This tray is positioned below the chamber 2, aligned perpendicularly with the opening 8 formed in the cylindrical wall of the chamber 2. Subsequently, it may be conceivable to refill the chamber 2 as described above and perform a new operation to transfer heat between the loose granular material and the fluid 15. Each time, the heat transfer operation includes filling the chamber 2 in use with the granular material, supplying fluid to the chamber through a cylindrical fluid receiving tube 3 at least partially located inside the chamber 2, and rotating the chamber 2 about its longitudinal axis XX'. This rotation is performed in parallel with the circulation of fluid inside the fluid receiving pipe 3.

Claims

1. A method for transferring heat between a granular material (14) capable of forming a movable bed and a fluid (15), When the cylindrical chamber (2) is in a configuration referred to as a "usage state" in which the longitudinal axis (XX') of the chamber (2) extends horizontally, - Fill the chamber (2) with granular material (14) in a volume corresponding to the movable bed to be formed. - At least a portion of the fluid is supplied to the chamber (2) via at least one cylindrical fluid receiving tube (3) located inside the chamber (2), and - Rotating the chamber (2) about an axis that coincides with the longitudinal axis (XX') of the chamber. Includes, The cylindrical fluid receiving tube (3) is a fixed tube (3) coaxial with the longitudinal axis (XX') of rotation of the chamber (2), and both ends of it are open to the outside of the chamber (2) so that they can be connected to the fluid circulation circuit (5), and, A method characterized in that the volume of granular material (14) for forming the moving bed within the cylindrical chamber (2) corresponds to filling the chamber (2) with granular material up to a filling height (H) within the range of heights defined by the formula: R + a × R1 [wherein R corresponds to the inner 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] [this filling height (H) corresponds to the level of the granular material (14) within the chamber (2) when the granular material (14) is evenly distributed throughout the chamber (2) and flattened].

2. The heat transfer method according to claim 1, characterized in that the rotation of the chamber (2) about an axis coinciding with the longitudinal axis (XX') of the chamber (2) is performed at an angular velocity between 5 and 50 rpm.

3. The heat transfer method according to claim 1 or 2, characterized in that the cylindrical chamber (2), bounded by a cylindrical wall (6) and two end faces (7), comprises at least one plugged opening (8) formed in the cylindrical wall (6) of the chamber (2) for filling and / or discharging granular material (14).

4. The heat transfer method according to claim 3, characterized in that the plugged 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. A granular material (14) capable of forming a movable bed and equipment (1) for heat transfer between the material and the fluid (15), Cylindrical chamber (2) [In the operating state, the longitudinal axis (XX') of the chamber (2) extends horizontally, and the chamber (2) can be filled with granular material (14) in a volume corresponding to the movable bed to be formed], At least one cylindrical fluid receiving tube (3) is at least partially located inside the chamber (2), and A rotational drive system (4) for rotating the chamber (2) about an axis that coincides with the longitudinal axis (XX') of the chamber (2). Includes, The fluid receiving pipe (3) is a fixed pipe (3) arranged coaxially with the longitudinal axis (XX') of rotation of the chamber (2), and both ends of it are open to the outside of the chamber (2) so that it can be connected to the fluid circulation circuit (5), and, The apparatus (1) is characterized in that the volume of granular material (14) for forming the moving bed in the cylindrical chamber (2) corresponds to filling the chamber (2) with granular material (14) up to a filling height (H) [wherein R corresponds to the inner 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] [this filling height (H) corresponds to the level of the granular material (14) in the chamber (2) when the granular material (14) is evenly distributed throughout the chamber (2) and flattened].

6. The heat transfer apparatus (1) according to claim 5, characterized in that the ratio of the inner radius (R) of the chamber (2) to the inner radius (R1) of the pipe (3) is between 3 and 15.

7. The heat transfer apparatus (1) according to claim 5 or 6, characterized in that the cylindrical chamber (2), bounded by a cylindrical wall (6) and two end faces (7), comprises at least one plugged opening (8) formed in the cylindrical wall (6) of the chamber (2) for filling and / or discharging granular material (14).

8. The heat transfer apparatus (1) according to claim 7, characterized in that the opening (8) extends from one end face (7) of the chamber (2) to the other end face (7).

9. The heat transfer equipment (1) according to any one of claims 5 to 8, wherein the equipment (1) includes at least one filling station for filling the chamber (2), the station includes at least one hopper (9) positioned above the chamber (2) when the chamber (2) is in use, and the hopper (9) is mounted to be movable along an axis parallel to the longitudinal axis (XX') of rotation of the chamber (2).

10. The heat transfer equipment (1) according to claim 7 or 8, characterized in that the equipment (1) includes a collector (10) for the granular material (14) contained within the chamber (2), and the collector (10) is positioned below the chamber (2) on a vertical line of the opening (8) formed in the cylindrical wall (6) of the chamber (2).

11. The heat transfer equipment (1) according to any one of claims 5 to 10, characterized in that the rotational drive system (4) for rotating the chamber (2) is configured to rotate the chamber (2) at an angular velocity between 5 and 50 rpm.

12. The heat transfer equipment (1) according to any one of claims 5 to 11, characterized in that the rotational drive system (4) for rotating the chamber (2) includes at least one rotating member (11) that meshes and engages with the outer portion of the chamber (2).

13. The heat transfer equipment (1) according to any one of claims 5 to 12, characterized in that the fluid (15) is a liquid, preferably water.

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