CN112387082A

CN112387082A - Dryer, compressor installation and method for drying compressed gas

Info

Publication number: CN112387082A
Application number: CN202010081124.2A
Authority: CN
Inventors: T·克雷佩因; G·黑勒曼斯
Original assignee: Atlas Copco Airpower NV
Current assignee: Atlas Copco Airpower NV
Priority date: 2019-08-16
Filing date: 2020-02-06
Publication date: 2021-02-23
Anticipated expiration: 2040-02-06
Also published as: CN212492276U; BE1027511B1; BE1027511A1; CN112387082B

Abstract

The present disclosure relates to a dryer for compressed gas, comprising: a pressure vessel having a drying zone and a regeneration zone therein; a drum arranged in the rotationally symmetric portion, the drum being provided with a regenerable desiccant; drive means for rotating the drum such that the desiccant moves through the drying zone and the regeneration zone in succession; an inlet for supplying compressed gas to be dried to the drying zone; an outlet for discharging the dried compressed gas; and a first connecting line for splitting a partial stream of the dried compressed gas and directing the partial stream to the regeneration zone. The first connecting line is provided with heating means for heating the partial stream that has been branched off for regeneration. The first connecting line and the heating device are arranged inside the pressure vessel.

Description

Dryer, compressor installation and method for drying compressed gas

Technical Field

The present invention relates to a dryer for compressed gas, a compressor installation provided with such a dryer and a method for drying compressed gas, such as air.

Background

Dryers for compressed gas are known, which are provided with a pressure vessel comprising a drying zone and a regeneration zone, and possibly a cooling zone; and a rotatable drum with regenerable desiccant is also included in the pressure vessel. The pressure vessel comprises an inlet for supplying compressed gas to be dried into the drying zone and an outlet for discharging the drying gas. Hot regeneration gas is introduced into the regeneration zone for regenerating the desiccant. The dryer further comprises a drive means for rotating the drum such that the desiccant moves continuously through the drying zone and the regeneration zone.

Compressed gas which has been heated by compression and thus has a low relative water content can be used as regeneration gas for regenerating the drying agent. In a first known embodiment, a portion of the supply flow of compressed gas is diverted for regeneration and subsequently reintroduced into the flow of compressed gas. In a second known embodiment, a portion of the exhaust stream of dry compressed gas is diverted and heated for regeneration and then reintroduced into the stream of compressed gas. In a third known embodiment, the flow of the entire supply of compressed gas to be dried is first led through the regeneration zone and then through the drying zone.

Other embodiments are also known, for example as disclosed in WO2015/039193A 2.

Disclosure of Invention

It is an object of the present invention to overcome one or more of the disadvantages of the prior art.

It is a further object of the invention to provide a dryer or drying apparatus for compressed gas with which the performance of the dryer, such as the performance of the dried compressed gas (e.g. pressure dew point) and/or the performance of the process (e.g. efficiency) can be improved.

Another object of the present invention is to provide a dryer or drying apparatus for compressed gas which has a relatively compact construction.

The compressed gas may be, for example, air, but it may also be another gas. The dry gas may be used in a downstream compressed air network for a wide range of purposes, such as for pneumatic transport, driving of pneumatic tools, etc.

In a first aspect which may be combined with other aspects or embodiments described herein, the present invention provides a dryer or drying apparatus for drying compressed gas, comprising: a pressure vessel comprising a rotationally symmetric (e.g., cylindrical) portion having a drying zone and a regeneration zone disposed therein; a drum disposed in the rotationally symmetric portion, the drum being provided with a regenerable desiccant; drive means for rotating the aforesaid drum with respect to said rotationally symmetrical portion, i.e. rotating the drum and/or the rotationally symmetrical portion, so that the desiccant moves successively through the drying zone and the regeneration zone; an inlet for supplying compressed gas to be dried into the drying zone; an outlet for discharging a dry compressed gas; and a first connection line for splitting a partial stream of the dried compressed gas and conveying the partial stream to the regeneration zone. On the outlet side, the drying zone is divided by a partition into a first outlet zone to which an outlet for the dried compressed gas is connected and a second outlet zone to which a first connecting line is connected. In other words, the first outlet zone and the second outlet zone are parts or spaces that are separated from each other within the pressure vessel on the outlet side of the drying zone.

The inventors have found that dividing the outlet side of the drying zone into a first outlet zone and a second outlet zone, in other words separating the partial flow for regeneration and the outflow flow of dried compressed gas sent to the outlet, at the location where the total flow of dried gas exits from the drum, enables the properties of the dried compressed gas sent to the outlet to be improved, or at least to be determined (i.e. controlled) more accurately.

The inventors have found that dividing the outlet side of the drying zone into a first outlet zone and a second outlet zone, in other words separating the partial flow for regeneration from the outgoing flow of dried compressed gas sent to the outlet, at the location where the total flow of drying gas exits from the drum, enables an improved operation of the dryer. This can take place, on the one hand, in a form which makes optimum use of the inherent heat in the supplied compressed gas and, on the other hand, in a form which achieves thorough drying of the drying agent, whereby the relative humidity of the compressed gas leaving the dryer can also be reduced as far as possible. Another object of the invention is to be able to ensure in an optimum manner a high efficiency of the dryer over the widest possible range of operating conditions.

The above and other effects may be obtained by pre-selecting the position of the first and second outlet regions relative to each other and the size of the first and second outlet regions, as will be further described herein. For example, simulations have revealed that by a predetermined selection of the positions of the first and second outlet zones with respect to each other and the dimensions and/or mutual proportions of said first and second outlet zones, the pressure dew point of the exhaust gas may be reduced and/or maintained more stable.

In an embodiment of the invention, the first outlet zone may be arranged before the second outlet zone, as seen in the direction of rotation of the drum. This means that the outlet for the dried compressed gas is connected to the sub-zone of the drying zone from which the relatively drier gas flows out.

In an embodiment of the invention, the first outlet zone may be arranged after the second outlet zone, as seen in the direction of rotation of the drum. This means that the connecting line for connecting the partial stream to the regeneration zone is connected to the sub-zone of the relatively drier gas outflow of the drying zone.

In an embodiment of the invention, positioning means may be provided for positioning the first outlet zone, the second outlet zone and/or the partition at the outlet side of the drying zone. With such a positioning device, it is possible, for example, to establish some well-defined positions or locations for the partition(s) of the generation zone inside the pressure vessel. In this way, assembly of the dryer may be facilitated.

In an embodiment of the invention, the regeneration zone and/or the second outlet zone may extend over a sector of the drum amounting to 45 ° to 135 °. Preferably, the regeneration zone and the second exit zone (the partial stream for regeneration) extend over sectors having substantially the same size. Preferably, the regeneration zone extends over a sector totaling 80 ° to 100 °. The first outlet zone may extend over a sector amounting for example to 90 ° to 180 °.

In an embodiment of the invention, the rotationally symmetrical part may further comprise a cooling zone for cooling the drum, which cooling zone is arranged after the regeneration zone and before the drying zone, as seen in the direction of rotation of the drum. Preferably, for this cooling, a partial flow is branched off from the drying gas, which partial flow is preferably guided from the adjacent side of the drying zone to the cooling zone.

In a second aspect which may be combined with other aspects or embodiments described herein, the present invention provides a dryer or drying apparatus for drying a compressed gas, comprising a pressure vessel having a rotationally symmetric (e.g. cylindrical) portion in which a drying zone and a regeneration zone are disposed; a drum arranged in a rotationally symmetric part, the drum being provided with a regenerable desiccant; drive means for rotating the aforesaid drum with respect to the rotationally symmetrical part, i.e. rotating the drum and/or the rotationally symmetrical part, so that the drying agent moves successively through the drying zone and the regeneration zone; an inlet for supplying compressed gas to be dried into the drying zone; an outlet for discharging a dry compressed gas; and a first connection line for splitting a partial stream of the dried compressed gas and conveying the partial stream to the regeneration zone. The first connecting line is provided with a heating device for heating the partial flow diverted for regeneration. The first connecting line and the heating device are arranged inside the pressure vessel. By integrating the first connecting line and the heating device inside the pressure vessel, a more compact construction can be achieved.

In an embodiment of the invention, the heating device may be a heat exchanger arranged for heating a partial stream which is branched off for regeneration with compressed gas to be dried and supplied to the dryer.

In an embodiment of the invention, an inlet for compressed gas to be dried and supplied to the dryer may be provided at the level of the heat exchanger, wherein a second connecting line is provided inside the pressure vessel for conducting compressed gas to be dried from the heat exchanger to the inlet side of the drying zone. The integration of the second connecting line inside the pressure vessel may further contribute to a more compact construction of the dryer.

In an embodiment of the invention, a venturi ejector may be provided in the second connecting line for combining the partial flow for regeneration with the flow of the supplied compressed gas to be dried. The integration of the venturi ejector within the pressure vessel may further contribute to a more compact construction of the dryer. The venturi ejector may be provided with a controllable opening and the dryer may comprise a drive means for driving the controllable opening.

In an embodiment of the invention, the dryer may further comprise a cooling device for cooling the supplied flow of compressed gas to be dried, which cooling device is arranged inside the pressure vessel at the inlet side of the drying zone. The integration of the cooling device ejector inside the pressure vessel may further contribute to a more compact construction of the dryer.

Another aspect of the invention relates to a compressor installation comprising a compressor and a dryer according to any of the aspects or embodiments described herein.

Another aspect of the invention relates to a method for drying compressed gas, said method utilizing a dryer according to any of the aspects or embodiments described herein.

Drawings

The invention will be described in more detail hereinafter with reference to exemplary embodiments thereof as shown in the accompanying drawings.

FIG. 1 is a schematic diagram of a compressor apparatus with a dryer according to the prior art;

FIG. 2 is a schematic view of a compressor apparatus having a dryer in accordance with a first embodiment of the present invention;

fig. 3a to 3c are schematic diagrams for comparing a dryer according to the prior art with a dryer according to the present invention.

Fig. 4 is a schematic view of a compressor apparatus having a dryer according to a second embodiment of the present invention.

Fig. 5 is a schematic view of a compressor apparatus having a dryer according to a third embodiment of the present invention.

Fig. 6 is a schematic view of a compressor apparatus having a dryer according to a fourth embodiment of the present invention.

Fig. 7 is a schematic cross-sectional view of a pressure vessel of a dryer according to a fourth embodiment.

Detailed Description

The present invention will be described with respect to certain embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting in scope. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale; this is for illustrative purposes. The dimensions and relative dimensions do not necessarily correspond to actual embodiments of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. The terms so used are interchangeable under appropriate circumstances and the embodiments of the invention can be used in other sequences than described or illustrated herein.

Furthermore, the terms "topmost," "upper," "bottommost," "lower," "above," "below," and the like in the description and in the claims, are used for descriptive purposes and not necessarily for describing relative positions. These terms are interchangeable under appropriate circumstances and the embodiments of the invention described herein can be used in other orientations than those described or illustrated herein.

Furthermore, the various embodiments which may be described as "preferred embodiments" are to be understood as merely illustrative means and modes for carrying out the invention and not as limiting the scope of the invention.

The term "comprising" as used in the claims should not be interpreted as being limited to the means or steps mentioned thereafter; the term does not exclude other elements or steps. The terms should be interpreted as specifying the presence of the described features, elements, steps or components, but does not preclude the presence or addition of one or more other features, elements, steps or components, or groups thereof. Thus, the scope of the expression "a device or apparatus comprising parts a and B" should not be taken to be limited to devices or apparatuses comprising only parts a and B. It is intended that only components a and B of the device are specifically mentioned in relation to the invention, but that the claims are to be further interpreted as including equivalents of these components.

Fig. 1 shows a known plant comprising a compressor plant with a dryer 1 for compressed gas. The dryer 1 includes: a pressure vessel having a drying zone 2 and a regeneration zone 3; a drum 4 rotatably arranged in the pressure vessel and provided with a regenerable drying agent; drive means for rotating the drum to move desiccant sequentially through the drying zone and the regeneration zone; an inlet 5 connected to an inlet side of a drying zone of the pressure vessel and arranged for supplying compressed gas to be dried; and an outlet 6 connected to the outlet side of the drying zone of the pressure vessel and arranged for discharging the dried compressed gas. The gas to be dried is supplied by a compressor 50, which may comprise a first compression stage 51, a second compression stage 52 and an intermediately arranged cooler (IC) 53. In the supply line, the compressed gas is first passed through a heat exchanger (heat exchanger HE) and/or a cooling device (aftercooler AC). At the outlet 6 of the dryer there is provided a connecting line 7 for splitting a partial flow of the dried compressed gas. This partial stream is led through a heat exchanger HE for heating using the heat present in the supply stream as a result of compression and is then led further to the regeneration zone 3. After regeneration, the partial stream is recombined with the supply stream of compressed gas to be dried. This takes place via a cooling device with a condensate separator (regenerative cooler RC) and a venturi ejector 8.

Fig. 2 shows a first embodiment of the apparatus according to the invention, which comprises a compressor apparatus 50 with a dryer 10 for compressed gas. The dryer includes: a pressure vessel 11 comprising a rotationally symmetric portion in which a drying zone 12 and a regeneration zone 13 are defined; a drum 14 arranged in the rotationally symmetrical part and provided with a reproducible drying means; drive means for rotating the drum relative to the rotationally symmetric part (i.e. rotating the drum 14 in the rotationally symmetric part), or rotating the rotationally symmetric part around the stationary drum 14, such that the desiccant moves successively through the drying zone and the regeneration zone. Preferably, the rotationally symmetric portion is cylindrical; however, this is not essential and other rotationally symmetric shapes are possible. The dryer further includes: an inlet 15 connected to an inlet side of the drying zone of the pressure vessel 11 and for supplying compressed gas to be dried; and an outlet 16 connected to an outlet side of the drying zone of the pressure vessel 11 and for discharging the dried compressed gas. The gas to be dried is supplied by a compressor 50, which may comprise a first compression stage 51, a second compression stage 52 and an intermediately arranged cooler (IC) 53. In the supply line, the compressed gas first passes through a heat exchanger (heat exchanger HE) and a cooling device (aftercooler AC) 55. On the outlet side of the dryer a connecting line 17 is provided for splitting a partial flow of the dried compressed gas. This partial stream is directed through heat exchanger 54 to be heated using the heat present in the supply stream as a result of compression and then further directed to regeneration zone 13. After regeneration, the partial stream is recombined with the supply stream of compressed gas to be dried. This is done by a condensate separator (regenerative cooler RC)56 and a venturi ejector 58 or other means for creating a pressure differential and maintaining a partial flow for regeneration, such as a blower.

On the outlet side, the drying zone is divided by a partition 18 into a first outlet zone 21 connected to the outlet 16 for the dried compressed gas and a second outlet zone 22 connected to the first connecting line 17. The partition 18 is arranged within the volume of the pressure vessel 11 in order to divide the flow of drying gas at the point where it comes out of the drum 14 (in the figure, at the top of the drum). In the embodiment according to fig. 2, the first outlet zone 21 is arranged after the second outlet zone 22, or vice versa, as seen in the direction of rotation of the drum. The partition 18 may be in the form of, for example, a wall or rib extending in a radial direction and co-formed on an upper portion of the pressure vessel, or may be in the form of a movable wall mounted on positioning means provided for this purpose, or may be part of a separate element arranged on top of the drum 14 (such as a heat exchanger as described further herein).

Fig. 3a to 3c are used to compare a dryer according to the prior art (fig. 3a) with a dryer according to the invention (fig. 3b to 3 c). In the known dryer according to fig. 3a, the partial stream for regeneration is branched off from the outlet line 6.

In the embodiment according to fig. 3b, the dryer is divided into a regeneration zone 13, a cooling zone 19 after the regeneration zone 13 in the direction of rotation, and a drying zone comprising successively in the direction of rotation a second outlet zone 22 and a first outlet zone 21. The dashed line 18 indicates a partition dividing the drying zone. The partial flow from the second outlet zone 22 is conducted to the regeneration zone 13 via a connecting line 17 separate from the outlet 6 and a heating device 24, for example a heat exchanger 54. The connecting line 17 and the heating device 24 may be arranged in the region of the pressure vessel, as described elsewhere herein. The partial flow of the drying gas coming out of the first outlet zone 21 is directed to the outlet 16 of the dryer. The cooling zone 19 is fed with a smaller partial flow from the adjacent part of the drying zone. This is well known to those skilled in the art and will not be described further herein.

In the embodiment according to fig. 3 b. The regeneration zone 13 and the second exit zone 22 each have a range of approximately 90 sectors. The cooling zone 19 extends over a much smaller sector and the remainder comprises a first outlet zone 21 ("formed by it") which therefore extends over a larger sector than the second outlet zone. The respective ranges of these regions may also be larger or smaller as described elsewhere herein.

The embodiment according to fig. 3c is similar to the embodiment of fig. 3 b. The difference is that the first outlet zone and the second outlet zone are reversed, i.e. the first outlet zone 31 connected to the outlet 16 is arranged before the second outlet zone 32 in the direction of rotation of the drum, which second outlet zone 32 is connected to the connecting line 27.

Fig. 4 shows a second embodiment according to the invention, comprising a compressor device 50 with a dryer 20 for compressed gas. The dryer 20 comprises a pressure vessel 11 comprising a rotationally symmetric portion in which a drying zone 12 and a regeneration zone 13 are defined; a drum 14 arranged in the rotationally symmetrical part and provided with a regenerable drying agent; and drive means for rotating the drum relative to the rotationally symmetric portion such that the desiccant moves successively through the drying zone and the regeneration zone. Preferably, the rotationally symmetric portion is cylindrical; however, this is not essential and other rotationally symmetric shapes are possible. The dryer further includes: an inlet 15 connected to an inlet side of the drying zone of the pressure vessel 11 and for supplying compressed gas to be dried; and an outlet 16 connected to the outlet side of the drying zone of the pressure vessel 11 and arranged for discharging the dried compressed gas. The gas to be dried is supplied by a compressor 50, which may comprise a first compression stage 51, a second compression stage 52 and an intermediately arranged cooler (IC) 53. In the supply line, the compressed gas first passes through a heat exchanger (heat exchanger HE) and a cooling device 57. On the outlet side of the dryer a connecting line 17 is provided for splitting off a partial flow of the dried compressed gas. This partial stream is directed through heat exchanger 54 to be heated using the heat present in the supply stream as a result of compression and then further directed to regeneration zone 13. After regeneration, the partial stream is recombined with the supply stream of compressed gas to be dried. This is done by venturi ejector 58 or other means (e.g., a blower) for creating a pressure differential and maintaining a partial flow for regeneration.

In the embodiment according to fig. 4, the merging of the main flow of compressed gas to be cooled and the partial flow for regeneration takes place upstream of the cooling. With this arrangement, both streams can be cooled jointly in a cooling device 57 (process cooler PC) arranged between the venturi ejector 58 and the inlet 15 of the pressure vessel 11. The cooling device 57 is preferably provided with a condensate separator. In other embodiments, the cooling device 57 may also be integrated into the pressure vessel, more particularly on the lower side between the inlet 15 and the inlet side of the drying zone 12.

As shown in fig. 2, in the embodiment according to fig. 4, the outlet side of the drying zone is divided by means of a partition 18 into a first outlet zone 21 connected to the outlet 16 for the dried compressed gas and a second outlet zone 22 connected to the first connecting line 17. In the embodiment according to fig. 4, the first outlet zone 21 is arranged after the second outlet zone, or vice versa, as seen in the direction of rotation of the drum, as described in relation to fig. 3.

Fig. 5 shows a third embodiment according to the invention, comprising a compressor device 50 with a dryer 30 for compressed gas. The dryer 30 includes: a pressure vessel 11 comprising a rotationally symmetric portion in which a drying zone 12 and a regeneration zone 13 are defined; a drum 14 arranged in the rotationally symmetrical part and provided with a regenerable drying agent; and drive means for rotating the drum relative to the rotationally symmetric portion such that the desiccant moves successively through the drying zone and the regeneration zone. Preferably, the rotationally symmetric portion is cylindrical; however, this is not essential and other rotationally symmetric shapes are possible. The dryer further includes: an inlet 15 connected to an inlet side of the drying zone of the pressure vessel 11 and for supplying compressed gas to be dried; and an outlet 16 connected to an outlet side of the drying zone of the pressure vessel 11 and for discharging the dried compressed gas. The gas to be dried is supplied by a compressor 50, which may comprise a first compression stage 51, a second compression stage 52 and an intermediately arranged cooler (IC) 53.

In the embodiment according to fig. 5, the flow of supplied compressed gas is first led via the supply line 28 through a heat exchanger 29 (which heat exchanger 29 is arranged at the top of the pressure vessel 11) and then to the inlet 15 of the pressure vessel 11. The heat exchanger 29 is arranged for heating the partial stream 27 for regeneration and this embodiment also comprises a partition 18 and a first connecting line 27 which separates the partial stream for regeneration from the stream of dry compressed gas discharged to the outlet 16 and diverts it to the regeneration zone 13. In this embodiment, the first connecting line 27 and the heat exchanger 29 are thus integrated into the pressure vessel 11.

In the embodiment according to fig. 5, the division of the drying zone 12 is as shown in fig. 3 c; more specifically, a first outlet zone 31 connected to the outlet 16 is arranged before a second outlet zone 32, which second outlet zone 32 is connected to the connecting line 27, as seen in the direction of rotation of the drum. In other embodiments, the opposite arrangement may be provided.

After regeneration, the partial stream is recombined with the supply stream of compressed gas to be dried. This is done by a venturi ejector 58 or other means for creating a pressure differential and maintaining a partial flow for regeneration (e.g., a blower). Similar to fig. 4, according to the embodiment of fig. 5, the merging of the main flow of compressed gas to be cooled and the partial flow for regeneration takes place upstream of the cooling. With this arrangement, both streams can be cooled jointly in a cooling device 57 (process cooler PC), preferably with a condensate separator, which is arranged between venturi injector 58 and inlet 15 of pressure vessel 11. In other embodiments, the cooling device 57 may also be integrated into the pressure vessel, more particularly on the underside between the inlet 15 and the inlet side of the drying zone 12. The cooling device 57 may be a passive device using cooling water (which is typically available from other sources in an industrial facility) as a coolant; or it may be an active device such as a refrigerator; or may be a combination of these. In a variant of this embodiment, similar to fig. 2, the main stream and the partial stream can be cooled separately before being combined, the cooling taking place by the after-cooler AC and the regenerative cooler RC, respectively, wherein only the regenerative cooler RC is integrated into the pressure vessel.

Fig. 6 shows a fourth embodiment according to the invention, comprising a compressor installation 50 with a dryer 40 for compressed gas. The dryer 40 includes: a pressure vessel 11 comprising a rotationally symmetric portion in which a drying zone 12 and a regeneration zone 13 are defined; a drum 14 arranged in the rotationally symmetrical part and provided with a regenerable drying agent; and drive means for rotating the drum relative to the rotationally symmetric portion such that the desiccant moves through the drying zone and the regeneration zone in succession. Preferably, the rotationally symmetric portion is cylindrical; however, this is not essential and other rotationally symmetric shapes are possible. The dryer further includes: an inlet 15 connected to the pressure vessel 11 for supplying compressed gas to be dried; and an outlet 16 connected out of the pressure vessel 11 for discharging the dried compressed gas. The gas to be dried is supplied by a compressor 50, which may comprise a first compression stage 51, a second compression stage 52 and an intermediately arranged cooler (IC) 53.

In the embodiment according to fig. 6, the flow of supplied compressed gas is first led via the supply line 28 through a heat exchanger 29, which heat exchanger 29 is arranged at the top of the pressure vessel 11. The heat exchanger 29 is arranged for heating the partial stream 27 for regeneration and this embodiment also comprises a partition 18 and a first connecting line 27 which separates the partial stream for regeneration from the stream of dry compressed gas discharged to the outlet 16 and diverts it to the regeneration zone 13. In this embodiment, the first connecting line 27 and the heat exchanger 29 are thus integrated into the pressure vessel 11.

In the embodiment according to fig. 6, the division of the drying zone 12 is as shown in fig. 3 c; more specifically, a first outlet zone 31 connected to the outlet 16 is arranged before a second outlet zone 32, which second outlet zone 32 is connected to the connecting line 27, as seen in the direction of rotation of the drum. In other embodiments, the opposite arrangement may be provided.

In the embodiment according to fig. 6, the inlet 15 for the compressed gas to be dried is arranged at the level of the heat exchanger 29 and the flow of supplied compressed gas is further conducted to the inlet side of the drying zone 12 in the interior of the pressure vessel 11. As shown, this preferably occurs through a central line or channel 38 in the middle of the roller 14. A venturi ejector 58 can also be arranged in this line 38, which venturi ejector 58 sucks in the partial flow for regeneration via a second central line or channel 39. In other embodiments, the main flow of compressed gas to be dried can also be further guided inside the pressure vessel via a line or channel extending through the outer cover of the drum; and a venturi ejector for merging the main flow and the partial flow for regeneration may be provided in the line or passage. Below the drum, similar to fig. 4 and 5, a common cooling device 57 (process cooler PC) is arranged, which is provided for cooling the combined stream (partial stream for regeneration is combined with the main stream), which is preferably integrated into the pressure vessel. In a variant of this embodiment, similar to fig. 2, the main flow and the partial flow can be cooled separately before being combined, the cooling being carried out by the after-cooler AC and the regenerative cooler RC, respectively, wherein only the regenerative cooler RC is integrated into the pressure vessel. With this arrangement, the cooling of the supply stream and the combination of the two streams is performed outside the pressure vessel.

In an embodiment of the invention, for example according to the embodiment of fig. 6, all the components of the dryer 40 may be integrated into a pressure vessel, more specifically: a heat exchanger 29 comprising a first connecting line 27; a connecting line 38 connecting the main flow from the heat exchanger 29 with the inlet side of the drying zone; a venturi ejector 58; a cooling device 57 with a condensate separator 60. In this way, a very compact dryer or drying apparatus can be achieved, having only one inlet 15 and only one outlet 16 for the compressed gas. Fig. 7 shows an embodiment of such an integrated dryer 40.

In the above-described embodiments according to the invention, the controllable means may be arranged for maintaining a pressure difference between the supply stream and the partial stream for regeneration, such that the flow rate of at least the partial stream is controllable. Such controllable means may comprise, for example, a venturi ejector 58 with a controllable opening, wherein the dryer is provided with drive means for driving the controllable opening. These drive means may for example be controlled by a control signal provided by a control unit which may for example evaluate one or more process parameters of the drying process in order to establish the control signal and thus the state of the controllable opening.

The above embodiments are applicable to all of the following embodiments: wherein a portion of the dried compressed gas exiting the drying zone is diverted and diverted to the regeneration zone or sub-zone thereof. This includes so-called "full flow" embodiments, in which the entire supply flow of compressed gas to be dried is first directed through the regeneration zone and then through the drying zone, wherein a portion of the flow of the then discharged dry gas is diverted and heated for further regeneration.

The heating device for heating the partial stream withdrawn for regeneration is preferably a heat exchanger which utilizes the heat inherently present in the compressed gas after compression, as in the embodiment described herein. In alternative embodiments, other heating devices may be used, optionally in combination with the above-described heat exchanger, such as an active electric heating device, or a heat exchanger that absorbs heat from another industrial process, or a combination thereof.

It goes without saying that the elements of the above-described embodiments may be combined with each other within the scope of the disclosure of the present specification.

Claims

1. A dryer (10; 20; 30; 40) for compressed gas, the dryer comprising:

a pressure vessel (11) comprising a rotationally symmetric portion having therein a drying zone (12) and a regeneration zone (13);

a drum (14) arranged in the rotationally symmetric part, the drum being provided with a regenerable desiccant;

drive means for rotating the drum relative to the rotationally symmetric portion or the rotationally symmetric portion relative to the drum such that the desiccant moves through the drying zone and the regeneration zone in succession;

an inlet (15) for supplying compressed gas to be dried;

an outlet (16) for discharging dry compressed gas; and

a first connection line for splitting a partial stream of dried compressed gas and conducting the partial stream to the regeneration zone, the first connection line being provided with a heating device for heating the partial stream that has been split for regeneration;

characterized in that the first connecting line (27) and the heating device (29) are arranged inside the pressure vessel.

2. The dryer according to claim 1, characterized in that the heating device is a heat exchanger (29) arranged for heating the partial flow, which is branched off for regeneration by means of the compressed gas to be dried supplied to the dryer.

3. Dryer according to claim 2, characterised in that an inlet (15) for compressed gas to be dried supplied to the dryer is provided at the level of the heat exchanger (29), and that inside the pressure vessel a second connecting line (38) is provided for leading compressed gas to be dried from the heat exchanger to the inlet side of the drying zone.

4. The drier according to claim 3, characterised in that a venturi ejector (58) is provided in the second connecting line for merging the partial flow for regeneration with the flow of the supplied compressed gas to be dried.

5. Dryer according to claim 4, characterized in that the venturi ejector (58) has a controllable opening and the dryer is provided with drive means for driving the controllable opening.

6. The dryer according to any one of the preceding claims, characterized in that the dryer comprises a cooling device for cooling a supplied flow of compressed gas to be dried, which cooling device is arranged inside the pressure vessel at the inlet side of the drying zone.

7. The dryer according to any one of the preceding claims, wherein the outlet side of the drying zone is divided by a partition (18) into a first outlet zone (21; 31) to which an outlet for the dried compressed gas is connected and a second outlet zone (22; 32) to which the first connecting line is connected.

8. The dryer according to claim 7, wherein the first outlet zone is arranged before the second outlet zone as seen in a direction of rotation of the drum.

9. The dryer according to claim 7, wherein the first outlet zone is arranged after the second outlet zone as seen in the direction of rotation of the drum.

10. The dryer according to claim 7, wherein the dryer comprises positioning means for positioning the first outlet zone, the second outlet zone and/or the partition at an outlet side of the drying zone.

11. The dryer according to any one of the preceding claims, wherein the pressure vessel further comprises a cooling zone (19) for cooling the drum, which cooling zone is arranged after the regeneration zone (13) and before the drying zone (12) as seen in the direction of rotation of the drum.

12. Compressor installation comprising a compressor (50) and further comprising a dryer (10; 20; 30; 40) according to any of the preceding claims.

13. A method of drying compressed gas using a dryer comprising a pressure vessel including a rotationally symmetric portion having a drying zone and a regeneration zone therein, the dryer further comprising a drum disposed in the rotationally symmetric portion, the drum being provided with a regenerable desiccant, the method comprising the steps of:

rotating the drum relative to the rotationally symmetric part or the rotationally symmetric part relative to the drum by a drive means such that the desiccant moves successively through the drying zone and the regeneration zone;

supplying compressed gas to be dried via an inlet to an inlet side of the drying zone of the pressure vessel;

discharging the dried compressed gas from the outlet side of the drying zone of the pressure vessel via an outlet;

splitting a partial stream of the dried compressed gas and conducting the partial stream to a regeneration zone via a first connection line, which is provided with a heating device for heating the partial stream that has been split for regeneration;

characterized in that the first connecting line and the heating device are arranged inside the pressure vessel such that heating of the partial stream that has been branched off for regeneration takes place inside the pressure vessel.