Drying device for compressed gas, compressor arrangement provided with drying device and method for using same

Abstract

The present disclosure at least relates to a drying apparatus for compressing a gas, a compressor arrangement provided with a drying apparatus, and a method of using the same. The drying apparatus comprises a dryer (4) equipped with a desiccant (5), the dryer being equipped with a drying section (6) having an inlet (11) and an outlet (12), and a regeneration section (7) having an inlet (13) and an outlet (14) for a regeneration gas, a regeneration line (15) being connected to the inlet (13), a branch line (17) being provided at the outlet (12) to the regeneration line (15), the pressure line (10) is connected to the inlet (11) of the drying section in which a cooler (18) and a cooler (19) are combined, the cooler (18) being cooled with a fan (20), the cooler (19) being cooled with a refrigerator (21), the fan (20) being controlled based on the calculated temperature at the inlet (11) when the refrigerator is turned off, and the refrigerator being controlled based on the actual temperature at the inlet (11).

Description

Technical Field

[0001] The invention relates to a drying device.

[0002] More particularly, the present invention relates to drying compressed gases. Background Art

[0003] Drying devices for compressed gases are known. These drying devices or dryers are equipped with a container having a drying zone, a regeneration zone and a cooling zone and a drum that can rotate in the container with a regenerable drying agent or dehumidifier.

[0004] The container comprises an inlet for supplying compressed gas to be dried and an outlet for dried compressed gas.

[0005] The regeneration section includes an inlet and an outlet for a regeneration gas for regenerating the desiccant. The drying apparatus also includes a driving member for rotating the drum so that the desiccant moves through the drying section and the regeneration section in sequence.

[0006] Typically, a regeneration line is connected to the inlet of the regeneration section, wherein, optionally, if necessary, a heat exchanger is integrated into the regeneration line for heating the regeneration gas.

[0007] The outlet of the drying section is usually equipped with a branch line connected to the regeneration line for branching off the regeneration gas at the outlet of the drying section.

[0008] The pressure line is connected to the inlet of the drying section, in which the first cooler and the second cooler are sequentially combined.

[0009] The coolers of known drying devices are cooled by forcing air over or through the cooler by means of a fan, or by means of a cooling medium, such as a cooling water circuit. Summary of the invention

[0010] The disadvantage of air-cooled chillers in this type of drying equipment is that the cooling capacity is often insufficient and therefore cannot be used in areas with high ambient temperatures.

[0011] A further disadvantage is the high energy consumption of this known drying device.

[0012] The present invention aims to provide a solution to at least one of these and other disadvantages.

[0013] To this end, the present invention relates to a drying device for drying compressed gas, comprising a dryer equipped with a desiccant or a dehumidifier, the dryer being equipped with a drying part and a regeneration part, the drying part having an inlet for compressed gas to be dried and an outlet for dried compressed gas, the regeneration part having an inlet and an outlet for regeneration gas, wherein a regeneration line is connected to the inlet of the regeneration part, wherein a branch line connected to the regeneration line is provided at the outlet of the drying part for branching out regeneration gas at the outlet of the drying part, wherein a pressure line is connected to the inlet of the drying part, wherein a first cooler and a second cooler are combined in sequence, characterized in that the first cooler is cooled by means of a fan with adjustable speed and the second cooler is cooled by means of a chiller, wherein when the chiller is turned off, the fan is controlled based on a calculated temperature T1 of the gas at the inlet of the drying part, and wherein the chiller is controlled based on an actual temperature T2 of the compressed gas at the inlet of the drying part.

[0014] The controller according to the invention combines a fan controller and a refrigerator controller which together ensure optimal and energy-saving cooling of the drying device.

[0015] Controlling the fan based on the calculated temperature T1 and controlling the refrigerator based on the actual temperature T2 ensures that the refrigerator is turned on only when the cooling capacity of the first cooler using the fan is insufficient, without affecting the performance of the drying device.

[0016] Energy is saved by switching on the refrigerator only when the cooling capacity of the first cooler using the fan is insufficient.

[0017] The increased cooling capacity, which is switched on only when necessary, ensures that target performance is achieved across the entire operating area.

[0018] The invention also relates to a method for drying compressed gas using a drying device, the drying device comprising a dryer equipped with a desiccant or a dehumidifier, the dryer being equipped with a drying section and a regeneration section, the drying section having an inlet for compressed gas to be dried and an outlet for dried compressed gas, the regeneration section having an inlet and an outlet for regeneration gas, wherein a regeneration line is connected to the inlet of the regeneration section, wherein a branch line connected to the regeneration line is provided at the outlet of the drying section for branching off regeneration gas at the outlet of the drying section, wherein a pressure line is connected to the inlet of the drying section, wherein a first cooler and a second cooler are sequentially combined, wherein the first cooler is cooled by means of an adjustable speed fan and the second cooler is cooled by means of a refrigerating machine, wherein the method comprises the following steps:

[0019] a) when the refrigerator is off, the fan is controlled based on the calculated temperature T1 of the gas at the inlet of the drying section;

[0020] b) Controlling the refrigerator based on the actual temperature T2 of the compressed gas at the inlet of the drying section.

[0021] According to a preferred aspect of the present invention, the method further comprises the following sub-steps:

[0022] a1) When the drying equipment is turned on, turn on the fan;

[0023] a2) As T1 increases, increase the fan speed;

[0024] And step b includes the following sub-steps:

[0025] b1) When T2 is higher than the threshold value T2_max, the refrigerator is started;

[0026] b2) Controlling the cooling capacity of the refrigerator so that T2 remains equal to the threshold value T2_max.

[0027] Preferably, in the method, the refrigerator is turned on when T2 is above a threshold value T2_max and the fan is running at its maximum speed.

[0028] In a preferred embodiment of the method, the controller will turn off the refrigerator when T2 drops below T2_max, wherein the controller will reduce the speed of the fan when T1 drops below T2_max by a certain value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to better illustrate the features of the present invention, preferred embodiments of the drying apparatus and compressor device according to the present invention and methods of use thereof will be described below in the form of non-limiting examples with reference to the accompanying drawings, in which:

[0030] Figure 1 A compressor arrangement with a drying device according to the invention is schematically represented;

[0031] Figure 2 A diagram schematically illustrating the method according to the invention is shown. DETAILED DESCRIPTION

[0032] Figure 1 The compressor device 1 schematically shown in FIG. 1 comprises a compressor 2 and a drying device 3, wherein the drying device 3 comprises a dryer 4 equipped with a desiccant 5 or a dehumidifying agent. The dryer 4 is equipped with a drying part 6 and a regeneration part 7.

[0033] In this case, the compressor 2 is a two-stage compressor with an intercooler 8, but the present invention is not limited thereto.

[0034] A pressure line 10 is connected to the outlet 9 of the compressor 2 .

[0035] The drying section 6 is equipped with an inlet 11 for the compressed gas to be dried and an outlet 12 for the dried compressed gas.

[0036] The regeneration section 7 is equipped with an inlet 13 and an outlet 14 for the regeneration gas, wherein a regeneration line 15 is connected to the inlet of the regeneration section 13 .

[0037] In this regeneration line 15 , in this case but not necessarily, a heat exchanger 16 is provided for heating the regeneration gas.

[0038] In this example, the heat exchanger 16 uses the compression heat of the compressed gas to be dried to heat the regeneration gas. In practice, the heat exchanger 16 is also integrated into the pressure line 10 .

[0039] The outlet 12 of the drying section 6 is provided with a branch line 17 connected to the regeneration line 15 for branching the regeneration gas at the outlet 12 of the drying section 6 .

[0040] The pressure line 10 is connected to the inlet 11 of the drying section 6, and a first cooler 18 and a second cooler 19 are sequentially incorporated in the pressure line 10. The heat exchanger 16 is incorporated in the pressure line 10 upstream of the first cooler 18.

[0041] The order here refers to the direction of compressed gas flow.

[0042] The first cooler 18 is cooled by means of a fan 20 of adjustable speed, while the second cooler 19 is cooled by means of a refrigerator 21 which in this case has a cooling water circuit 22 .

[0043] However, it is not excluded that the first cooler 18 is cooled using the refrigerator 21 and the second cooler 19 is cooled by means of the fan 20 .

[0044] The refrigeration machine 21 can be part of the drying device 3 or the compressor device 1 or, alternatively, can be located externally, which can have a positive effect on the efficiency.

[0045] In the embodiment shown, the return line 23 is connected to the outlet 14 of the regeneration section 7 , which connects the outlet 14 of the regeneration section 7 with a point of the pressure line 10 downstream of the second cooler 19 .

[0046] In this case, the return line 23 is connected to the pressure line 10 by means of a venturi 24 .

[0047] In this example, a third cooler 25 is provided in the return line 23. The third cooler 25 is also cooled by the fan 20 in this case.

[0048] However, it is not excluded that the third cooler 25 is cooled by a separate fan 20 .

[0049] In this example, the return line 23 is also equipped with a liquid separator 26 for discharging condensed water from the first cooler 18 and the second cooler 19. However, the position of the liquid separator 26 is not fixed, and one or more liquid separators 26 can also be installed in other places of the drying device 3.

[0050] In this example, the drying device 3 is equipped with a housing 27 in which the drying section 6 and the regeneration section 7 are located.

[0051] In this housing 27, a drum 28 containing a desiccant 5 or a dehumidifying agent is arranged. This drum 28 is connected to a driving member so that the drying member 5 is advanced through the drying section 6 and the regenerating section 7 in sequence.

[0052] Alternatively, the dryer 4 may include a plurality of containers filled with the desiccant 5 , wherein at least one container forms the drying section 6 , and at least one container forms the regeneration section 7 .

[0053] In this case, such a dryer 4 comprises a valve system which connects the outlet 12 , the regeneration line 15 and optionally the return line 23 and the branch line 17 to the container.

[0054] The valve system is then configured so that at least one vessel is always regenerating while the other vessels are drying the compressed gas. The valve system is controlled to regenerate each vessel in turn.

[0055] According to the invention, when the refrigerator 21 is turned off, the fan 20 is controlled based on the calculated temperature T1 of the gas at the inlet 11 of the drying section 6. However, the refrigerator 21 is controlled based on the actual temperature T2 of the compressed gas at the inlet 11 of the drying section 6. This temperature T2 is measured, for example, using a sensor provided for this purpose at the inlet 11.

[0056] In this example, the drying device 3 is equipped with a controller 29 for the fan 20 and the refrigerator 21. The controller 29 will control the fan 20 based on T1.

[0057] The refrigerator 21 is controlled based on T2 and is switched on when T2 is above a threshold value T2_max. The cooling capacity of the refrigerator 21 is selected so that T2 remains equal to the threshold value T2_max.

[0058] In this example, when T2 drops below T2_max, the controller 29 will turn off the chiller 21, and when T1 drops below T2_max by a certain value, the speed of the fan 20 will be reduced.

[0059] The operation of the drying device 3 is very simple and is illustrated by means of example diagrams, such as Figure 2 as shown in .

[0060] The graph shows time (in hours) as the independent variable, and the temperature and load LC of the chiller and the fan speed LF (in percent of maximum) as the dependent variables.

[0061] Tamb displays the change of ambient temperature over time.

[0062] At 04:00, the compressor system 1 is started, with the controller 29 turning on the fan. In this example, the speed of the fan 20 is initially set to 6% of the maximum value.

[0063] The speed of the fan 20 increases as T1 increases. At about 11:45, T2 becomes higher than T2_max. Since the fan 20 is running at its maximum speed at this time, the controller 29 controls the refrigerator 21.

[0064] The cooling capacity of the refrigerator 21 is controlled such that T2 remains equal to the threshold value T2_max and is therefore no longer dependent on Tamb.

[0065] However, the calculated value T1 continues to increase as if the refrigerator 21 does not exist.

[0066] After 16:00, Tamb decreases again, and from then on, the cooling capacity of the refrigerator 21 decreases again, while T2 remains equal to T2_max.

[0067] At about 20:00, T2 falls below T2_max again. Therefore, the refrigerator 21 is turned off, and the fan 20 continues to run at its maximum speed for more than half an hour. Alternatively, the fan 20 can also be turned off immediately.

[0068] The speed of the fan 20 is reduced only when T1 falls below T2_max which is reduced by a certain value.

[0069] As Tamb and T1 continue to decrease, the speed of the fan 20 further decreases.

[0070] Although the shown example describes a compressor device 1 , it cannot be excluded that the drying apparatus 3 and the compressor 2 are not part of the same device 1 .

[0071] It should be clear to a person skilled in the art that the first cooler 18 and the third cooler 25 may also be replaced by one process cooler, in which case the process cooler is located downstream of the venturi 24 and is followed by the second cooler 19 .

[0072] Although three coolers 18 , 19 , 25 are shown in this example, the number of coolers is not limited in practice.

[0073] The invention is in no way limited to the embodiments described as examples and shown in the drawings, but the compressor device, the drying apparatus and the method used according to the invention can be realized in all shapes and dimensions without departing from the scope of the invention.

Claims

1. A drying device for drying compressed gas, comprising a dryer (4) equipped with a desiccant (5) or a dehumidifier, the dryer being equipped with a drying section (6) and a regeneration section (7), the drying section having an inlet (11) for the compressed gas to be dried and an outlet (12) for the dried compressed gas, the regeneration section having an inlet (13) and an outlet (14) for the regeneration gas, wherein a regeneration line (15) is connected to the inlet (13) of the regeneration section (7), wherein a branch line (17) is provided at the outlet (12) of the drying section (6), the branch line being connected to the regeneration line (15) for branching out the regeneration gas at the outlet (12) of the drying section (6), wherein a pressure line (10) is connected to the inlet (11) of the drying section (6), wherein a first cooler (18) and a second cooler (19) are sequentially combined, characterized in that The first cooler (18) is cooled by means of a fan (20) with adjustable speed, and the second cooler (19) is cooled by means of a refrigerator (21), wherein when the refrigerator (21) is switched off, the fan (20) is controlled based on a calculated temperature T1 of the gas at the inlet (11) of the drying section (6), and wherein the refrigerator (21) is controlled based on an actual temperature T2 of the compressed gas at the inlet (11) of the drying section (6).

2. The drying device according to claim 1, characterized in that: The drying device (3) is equipped with a controller (29) for the fan (20) and the refrigerator (21), wherein the controller (29) controls the fan (20) based on T1, wherein the speed of the fan (20) increases as T1 increases, and wherein the refrigerator (21) is controlled based on T2, wherein when T2 is above a threshold value T2_max, the refrigerator (21) is turned on, wherein the cooling capacity of the refrigerator (21) is selected so that T2 remains equal to the threshold value T2_max.

3. The drying device according to claim 2, characterized in that: When T2 is above the threshold T2_max and the fan (20) is running at its maximum speed, the refrigerator (21) is turned on.

4. Drying device according to any one of the preceding claims 2 or 3, characterized in that When T2 drops below T2_max, the controller (29) will turn off the refrigerator (21), and wherein when T1 drops below T2_max by a certain value, the controller (29) will reduce the speed of the fan (20).

5. Drying device according to any one of the preceding claims, characterized in that A heat exchanger (16) is provided in the regeneration line (15) for heating the regeneration gas.

6. The drying device according to claim 5, characterized in that: The heat exchanger (16) uses the heat of compression of the compressed gas to be dried to heat the regeneration gas.

7. Drying device according to any one of the preceding claims, characterized in that The return line (23) is connected to the outlet (14) of the regeneration section (7), which connects the outlet of the regeneration section (7) to a point on the pressure line (10) downstream of the second cooler (19).

8. Drying device according to any one of the preceding claims, characterized in that A third cooler (25) and an optional liquid separator (26) are integrated into the return line (23), wherein the third cooler (25) is cooled by the fan (20).

9. The drying device according to claim 7 or 8, characterized in that: The return line (23) is connected to the pressure line (10) via a venturi (24).

10. Drying device according to any one of the preceding claims 5 to 9, characterized in that A heat exchanger (16) is provided in the pressure line (10) upstream of the first cooler (18).

11. Drying device according to any one of the preceding claims, characterized in that The first cooler (18) and / or the second cooler (19) is equipped with a liquid separator (26).

12. Drying device according to any one of the preceding claims, characterized in that The dryer (4) is provided with a housing (27) in which the drying section (6) and the regeneration section (7) are located, wherein a drum (28) containing the desiccant (5) is arranged in the housing (27) and is connected to a drive member so that the desiccant (5) can be moved sequentially through the drying section (6) and the regeneration section (7).

13. Drying device according to any one of the preceding claims, characterized in that The dryer (4) comprises a plurality of containers filled with a desiccant (5), wherein at least one container forms a drying section (6) and at least one container forms a regeneration section (7), wherein the dryer (4) further comprises a valve system connecting an outlet line (9), a regeneration line (15) and an optional return line (23) as well as a branch line (17) to the containers, wherein the valve system enables at least one container to be regenerated at all times while the other containers dry the compressed gas, wherein each container is regenerated in turn by controlling the valve system.

14. A compressor arrangement comprising a compressor (2) and a drying device (3) according to any one of the preceding claims.

15. A method for drying compressed gas using a drying device (3), the drying device comprising a dryer (4) equipped with a desiccant (5) or a dehumidifier, the dryer being equipped with a drying section (6) and a regeneration section (7), the drying section having an inlet (11) for the compressed gas to be dried and an outlet (12) for the dried compressed gas, the regeneration section having an inlet (13) and an outlet (14) for the regeneration gas, wherein a regeneration line (15) is connected to the inlet (13) of the regeneration section (7), wherein the ...1) of the regeneration section (7), wherein the regeneration line (15) is connected to A branch line (17) is provided at the outlet (9) of the drying section (6), which branch line is connected to the regeneration line (15) for branching off the regeneration gas at the outlet (9) of the drying section (6), wherein a pressure line (10) is connected to the inlet (11) of the drying section (6), wherein a first cooler (18) and a second cooler (19) are successively combined, wherein the first cooler (18) is cooled by means of a fan (20) with adjustable speed, and the second cooler (19) is cooled by means of a refrigerator (21), characterized in that The method comprises the following steps: a) when the refrigerator (21) is turned off, controlling the fan (20) based on the calculated temperature T1 of the gas at the inlet (11) of the drying section (6); b) Controlling the refrigerator (21) based on the actual temperature T2 of the compressed gas at the inlet (11) of the drying section (6).

16. The method according to claim 15, characterized in that Step a includes the following sub-steps: a1) when the drying device (3) is turned on, the fan (20) is turned on; a2) increasing the speed of the fan (20) as T1 increases; And step b includes the following sub-steps: b1) When T2 is higher than the threshold value T2_max, the refrigerator (21) is turned on; b2) Controlling the cooling capacity of the refrigerator (21) so that T2 remains equal to the threshold value T2_max.

17. The method according to claim 16, characterized in that When T2 is above the threshold T2_max and the fan (20) is running at its maximum speed, the refrigerator (21) is turned on.

18. The method according to any one of the preceding claims 15 to 17, characterized in that When T2 drops below T2_max, the controller (29) will turn off the refrigerator (21), and wherein when T1 drops below T2_max by a certain value, the controller will reduce the speed of the fan (20).

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