CN112387084A - Dryer for compressed gas, compressor installation and method for drying compressed gas - Google Patents
Dryer for compressed gas, compressor installation and method for drying compressed gas Download PDFInfo
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- CN112387084A CN112387084A CN202010081447.1A CN202010081447A CN112387084A CN 112387084 A CN112387084 A CN 112387084A CN 202010081447 A CN202010081447 A CN 202010081447A CN 112387084 A CN112387084 A CN 112387084A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/26—Drying gases or vapours
- B01D53/261—Drying gases or vapours by adsorption
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/26—Drying gases or vapours
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
- B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
- B01D53/0454—Controlling adsorption
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
- B01D53/06—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with moving adsorbents, e.g. rotating beds
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
- F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
- F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
- F24F3/1411—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification by absorbing or adsorbing water, e.g. using an hygroscopic desiccant
- F24F3/1423—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification by absorbing or adsorbing water, e.g. using an hygroscopic desiccant with a moving bed of solid desiccants, e.g. a rotary wheel supporting solid desiccants
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2259/00—Type of treatment
- B01D2259/40—Further details for adsorption processes and devices
- B01D2259/40083—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption
- B01D2259/40086—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption by using a purge gas
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
- F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
- F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
- F24F2003/1458—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification using regenerators
- F24F2003/1464—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification using regenerators using rotating regenerators
Abstract
The invention relates to a dryer for compressed gas, a compressor installation and a method for drying compressed gas. A dryer for compressed gas comprising: a pressure vessel having a drying zone and a regeneration zone therein; a drum provided with a regenerable desiccant; drive means for rotating the drum to move the desiccant sequentially through the drying zone and the regeneration zone; an inlet for supplying compressed gas to be dried; and an outlet for discharging the dried compressed gas. The drive means comprises a motor provided with a start/stop controller.
Description
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 may also comprise a cooling zone; also included is a rotatable drum in the pressure vessel having a regenerable desiccant. The pressure vessel includes: an inlet for supplying compressed gas to be dried into the drying zone; and an outlet for discharging the dried gas. Hot regeneration gas is introduced into the regeneration zone to regenerate the desiccant. The dryer further comprises drive means for rotating the drum such that the desiccant moves through the drying zone and the regeneration zone in succession.
Compressed gas which has been heated by compression and therefore has a lower relative moisture content can be used as regeneration gas for regenerating the desiccant. In a first known embodiment, a portion of the compressed gas supply stream is branched off for regeneration and subsequently reintroduced into the compressed gas stream. In a second known embodiment, a portion of the dried compressed gas effluent stream is branched off and heated for regeneration and then reintroduced into the compressed gas stream. In a third known embodiment, the entire supply flow of compressed gas to be dried is first led through the regeneration zone and subsequently through the drying zone.
Other embodiments are also known, for example as disclosed in WO 2015/039193 a 2.
It is known to merge the partial flow already used for regeneration with the supply flow of the compressed gas to be dried, upstream on the inlet side of the drying zone. In this regard, a venturi ejector or blower is employed to create a pressure differential that maintains the split flow.
Disclosure of Invention
The object of the present invention is to remedy one or more of the drawbacks of the prior art.
The object of the invention is to provide a dryer or a drying device for compressed gas, in which the operation of the dryer can be better controlled by simple means.
The compressed gas may be, for example, air, but may also be another gas. The dried gas can be used in downstream compressed air networks for a wide range of applications, such as for pneumatic conveying, driving pneumatic tools, etc.
In a first aspect of the invention, which may be combined with other aspects or embodiments herein, the invention provides a dryer or drying apparatus for drying a compressed gas, comprising: a pressure vessel having a rotationally symmetric portion (e.g., cylindrical) in which a drying zone and a regeneration zone are present; a drum disposed in the rotationally symmetric portion, the drum being provided with a regenerable desiccant; drive means for rotating the drum relative to the rotational symmetry, i.e. rotating the drum and/or the rotational symmetry, so that the drying agent moves successively through the drying zone and the regeneration zone; an inlet for supplying compressed gas to be dried towards the drying zone; an outlet for discharging the dried compressed gas; and a first connecting line for branching off a divided flow of the compressed gas to be dried or a divided flow of the dried compressed gas and guiding the divided flow to the regeneration zone. The dryer further comprises controllable means arranged for merging the partial flow for regeneration with the supply flow of the compressed gas to be dried and for controlling the flow rate of the partial flow with respect to the supply flow; at least one sensor for measuring at least one measurement value related to the operation of the dryer; and a control unit communicatively connected to the at least one sensor and the controllable device and arranged to process the at least one measurement value, determine at least one control signal for controlling the controllable device based on the at least one measurement value, and apply the at least one control signal to the controllable device. By means of one or more measured values, the control unit can influence the operation of the dryer by adjusting the control signal and thus at least the flow of the partial flow for regeneration, in order to achieve, for example, a desired value of the pressure dew point and/or a desired stability of the pressure dew point within a defined range.
In embodiments of the present invention, a set of sensors may include one or more sensors for directly or indirectly measuring supply flow rate and/or bypass flow rate. The control unit may be arranged for evaluating a directly or indirectly measured supply flow rate and/or a shunt flow rate and applying the control signal based on the evaluation. The set of sensors may include, for example: a speed sensor for measuring the speed of the compressor supplying the supply stream as a measure of the flow rate of the supply stream; and/or a pressure sensor for measuring the pressure drop across the controllable device as a measure of the flow of the split stream for regeneration.
In an embodiment of the invention, the set of sensors may comprise one or more of the following sensors: a temperature sensor for measuring a temperature difference between an inlet side and an outlet side of the regeneration zone; a temperature sensor for measuring a temperature difference between an inlet side and an outlet side of the drying zone; and a pressure dew point sensor at the outlet for measuring a pressure dew point of the dried compressed gas effluent stream.
In an embodiment of the invention, the first connection line may be provided with a heat exchanger for heating a partial flow branched off for regeneration by the compressed gas to be dried and supplied to the dryer, and the set of sensors may comprise one or more of the following sensors: a pressure sensor for measuring a pressure difference between an outlet side of the drying zone and an inlet side of the regeneration zone; and a pressure sensor for measuring the pressure drop caused by the heat exchanger in the partial flow and/or in the supply flow.
In an embodiment of the invention, the dryer may comprise at least one cooling device arranged to cool the compressed gas supply stream, and/or to cool the split stream for regeneration, and/or to cool the combined stream; and the set of sensors may include one or more of the following sensors: temperature sensors for measuring the temperature of the respective streams upstream and/or downstream of the respective cooling devices; a pressure sensor for measuring a pressure drop in the respective flow caused by the respective cooling device; and a temperature sensor for measuring the temperature of the coolant for cooling upstream and/or downstream of the cooling device.
In an embodiment of the invention, the controllable device may comprise a venturi ejector arranged to merge the split and supply flows together and provided with a controllable opening, and having a drive device for driving the controllable opening on the basis of a control signal.
In an embodiment of the invention, the control unit may be in communication connection with a drive device for rotating the drum relative to the rotational symmetry, and the control unit may be arranged for determining a second control signal for the drive device based on the at least one measurement value and applying the second control signal to the drive device.
In an embodiment of the invention, the control unit may be in communication connection with one or more of the at least one cooling device and may be arranged for determining at least one third control signal for the at least one cooling device based on the at least one measurement value and applying the respective third control signal to the respective cooling device.
In a second aspect of the invention, which may be combined with other aspects or embodiments herein, the invention provides a dryer or drying apparatus for drying a compressed gas, comprising: a pressure vessel having a rotationally symmetric portion (e.g., cylindrical) in which a drying zone and a regeneration zone are present; a drum disposed in the rotationally symmetric portion, the drum being provided with a regenerable desiccant; drive means for rotating the drum relative to the rotational symmetry, i.e. rotating the drum and/or the rotational symmetry, such that the desiccant moves through the drying zone and the regeneration zone in succession; an inlet for supplying compressed gas to be dried towards the drying zone; an outlet for discharging the dried compressed gas; and a first connecting line for branching off a branched flow of the compressed gas to be dried or a branched flow of the dried compressed gas and guiding the branched flow to the regeneration zone. The drive means for rotating the drum relative to the rotational symmetry comprise a motor, preferably an electric motor, with a start/stop control, preferably for rotating the drum.
The start/stop controller is arranged to switch the motor on and off, thereby providing an adjustable average rotational speed of the drum relative to the rotational symmetry. More specifically, the start/stop controller is arranged to switch the motor on and off during a preferably continuous operation of the dryer, wherein on the one hand a continuous flow of compressed gas is supplied to the drying zone and dried in the drying zone, and on the other hand a continuous (partial) flow of compressed gas to be dried or compressed gas after drying is led to the regeneration zone for regenerating the drying agent. The start/stop controller is economically more advantageous than a frequency controller for adjusting the rotational speed of the electric motor, and thus can provide cost savings in terms of investment costs. Furthermore, the start/stop controller is less complex, as it requires less control electronics. In addition, the start/stop controller may rotate the drum in stages with respect to the rotationally symmetric portion, thus, for example, each time a zone having a regeneration zone size (or a portion thereof) is precisely moved, and then the movement of the zone is stopped for a given period of time. Another advantage of the start/stop controller is that the range of average rotational speeds is wider than when frequency control is employed; in particular, the average rotational speed may be adjusted from 0 to the maximum speed of the motor.
In an embodiment of the invention, the start/stop controller may be controlled by the same control unit as described elsewhere herein by means of a second control signal, which may be determined by the control unit based on measurements derived from the set of sensors.
Another aspect of the invention relates to a compressor installation comprising a compressor and a dryer according to any aspect or embodiment herein.
Another aspect of the invention relates to a method for drying compressed gas using a dryer according to any aspect or embodiment 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 shows a first embodiment of a compressor installation comprising a dryer according to the invention.
Fig. 2 shows a second embodiment of a compressor installation comprising a dryer according to the invention.
Fig. 3 shows a third embodiment of a compressor installation comprising a dryer according to the invention.
Fig. 4 shows a fourth embodiment of a compressor installation comprising a dryer according to the invention.
Fig. 5 shows a fifth embodiment of a compressor installation comprising a dryer according to the invention.
Fig. 6 shows a detail of an embodiment of a controllable device that can be used in the embodiments according to fig. 1 to 5.
Fig. 7A and 7B show an embodiment of a usable start and stop control device for driving the drum in the embodiment according to fig. 1 to 5.
Detailed Description
The invention will be described below with reference to some embodiments and with reference to some drawings, but the invention is not limited thereto but only established 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 ease of illustration. The dimensions and relative dimensions do not necessarily correspond to practical embodiments of the invention.
Furthermore, the terms first, second, third and the like may be 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 practiced in other sequences than described or illustrated herein.
The terms "topmost," "upper," "bottommost," "lower," "above," "below," and the like in the description and in the claims are also used for purposes of example and are not necessarily used to describe relative positions. These terms are interchangeable under appropriate circumstances and the embodiments of the invention described herein can be practiced in other orientations than described or illustrated herein.
In addition, the various embodiments which may be described as "preferred embodiments" are to be construed as merely illustrative of means and modes for carrying out the invention and not as limitations on 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, but rather should be interpreted as excluding other elements or steps. The terms are to be interpreted as specifying the presence of the stated features, elements, steps or components as referred to, 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 "an apparatus or device comprising means a and B" should not be taken as being limited to an apparatus or device consisting only of components a and B. It is intended that for the purposes of this invention, only the components a and B of the device be specifically referred to, but the claims should be further construed to include equivalents of those components.
In the embodiments of the compressor installation shown in fig. 1 to 5, the compressor 60 is provided in each case with a dryer 10 for compressed gas; 30, of a nitrogen-containing gas; 50; 70; 90. in each case, the dryer comprises: a pressure vessel 11, the pressure vessel 11 comprising a rotational symmetry in which a drying zone 12 and a regeneration zone 13 are defined; a drum 14 provided in the rotationally symmetrical portion and provided with a regenerable desiccant; a drive 114 for rotating the drum relative to the rotational symmetry, i.e. rotating the drum 14 in the rotational symmetry or rotating the rotational symmetry around a stationary drum, 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 symmetrical shapes are possible. The dryer further includes: an inlet 15 connected to an inlet side of the drying zone of the pressure vessel 11 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 for discharging the dried compressed gas. The gas to be dried is supplied by a compressor 60, which compressor 60 may comprise a first compression stage 61, a second compression stage 62 and an interposed cooler ("intercooler") ("IC") 63. In the delivery line from the compressor 60 to the inlet 15, the compressed gas may pass through a heat exchanger (heat exchanger HE)64 and/or a cooling device (aftercooler AC) 65.
In the embodiment according to fig. 1 to 3, at the outlet side of the compressor 60, a portion of the compressed gas to be dried (having an increased temperature due to the compression) branches off and is passed to the regeneration zone for regeneration. In the embodiment according to fig. 1, this is done via the connection line 17 without further heating of the partial streams. In the embodiment according to fig. 2, the partial flow is first further heated by an active heating device 31, for example an electric heating device. In the exemplary embodiment according to fig. 3, the partial flow 51 is first of all further divided into a "first partial flow" 52 and a "second partial flow" 53, wherein only the "first partial flow" 52 is further heated by the heating device 54. As shown, the "first split" 52 and the "second split" 53 are introduced into different regions of the regeneration zone 13, respectively.
In the embodiment according to fig. 4 and 5, the connection line 77; 97 are provided on the outlet side of the dryer for branching off the partial flow of the dried compressed gas. The split stream is directed through heat exchanger 64 to be heated with the heat present in the supply stream as a result of compression and then further directed to regeneration zone 13.
In each of the embodiments according to fig. 1 to 5, the partial flow for regeneration is returned via a connection line 19 to the main line 18 for the supply flow of compressed gas to be dried. This is done by a controllable device such as a venturi ejector 21 or other controllable device for creating a pressure differential and maintaining a split flow for regeneration, as described further herein. One or more cooling devices, for example the illustrated aftercooler 65 ("aftercooler AC") and/or the regenerative cooler 20 ("regenerative cooler RC") and/or the process cooler 91 ("process cooler PC"), may be provided in the connection line 19 and/or the main line 18 and/or at the inlet 15 (after merging), each cooler being provided for cooling a respective gas flow by means of a coolant, for example cooling water or ice water.
In the embodiment according to fig. 1 to 5, the following sensors may be provided for measuring the temperature of the respective compressed gas flow:
t1: a temperature sensor at the inlet 15;
t2: a temperature sensor at the outlet 16;
t3: a temperature sensor at the inlet side of the regeneration zone 13;
t4: a temperature sensor at the outlet side of the regeneration zone 13;
t5: a temperature sensor at the outlet side of the compressor (while being the inlet side of the heat exchanger 64 or aftercooler 65);
t6: a temperature sensor in the main line 18 (between the aftercooler 65 and the venturi ejector 21);
t7: a temperature sensor in the connection line 19 (between the regenerative cooler 20 and the venturi ejector 21);
t8: a temperature sensor at the outlet side of the heat exchanger 64.
In the embodiments according to fig. 1 to 5, pressure sensors can be provided for measuring the pressure difference in the respective compressed gas flow over the respective elements, in each case providing a measure of the respective gas flow, as follows:
dP 21: a pressure sensor for measuring the differential pressure across the venturi ejector 21 (see also fig. 6);
dPREG: a pressure sensor for measuring the pressure difference between the outlet side of the drying zone 12 and the inlet side of the regeneration zone 13;
dPHEhot: a pressure sensor for measuring the pressure difference generated by the heat exchanger 64 in the supply flow of compressed gas to be dried supplied by the compressor 60;
dPHEcold: a pressure sensor for measuring the pressure difference generated by the heat exchanger 64 in the partial flow branched off for regeneration purposes.
In the exemplary embodiments according to fig. 1 to 5, the following sensors can additionally be provided:
"RPM": a sensor for measuring the rotational speed of the compressor 60, providing a measure of the flow of the supply gas to be dried;
"PDP": a pressure dew point sensor for measuring the pressure dew point at outlet 16;
TACinand TACout: temperature sensors for measuring the coolant (cooling water) temperature at the inlet and outlet of the after cooler 65;
TRCinand TRCout: temperature sensors for measuring the temperature of the coolant (cooling water) at the inlet and outlet of the regenerative cooler 20;
TPCinand TPCout: temperature sensors for measuring the temperature of the coolant (cooling water) at the inlet and outlet of the process cooler 91.
In the embodiments according to fig. 1 to 5, a control unit 100 is provided in each case. Each of the above sensors may be provided with means for communicating with the control unit 100. The communication connection may be wireless or wired; for the sake of clarity, they are not shown in fig. 1 to 5.
In the embodiments according to fig. 1 to 5, in each case at least the merging means which merges the partial flow for regeneration with the main flow of the supply gas to be dried is designed as a controllable device 21, 121. The control unit 100 is at least arranged for processing at least one measurement value provided by the above-mentioned sensor, for determining a first control signal 101 for the above-mentioned controllable device on the basis of the at least one measurement value, and for applying the first control signal to the controllable device. The controllable means may comprise, for example, a venturi ejector 21 with a controllable opening (see fig. 6). The controllable device may further comprise: a blower having a control for blower speed; or a plurality of smaller venturi ejectors or nozzles arranged in parallel with respective controls for opening or closing them respectively. This has the advantage that the controllable device can be smaller in size than a single venturi ejector, and therefore can be better integrated into the pressure vessel. Also, alternatively, the controllable device may comprise a venturi ejector with a controllable bypass around it. Other controllable devices are also possible.
In the embodiment according to fig. 1, the first control signal 101 is determined at least on the basis of an RPM sensor (compressor RPM: supply flow of compressed gas) and a dP21 sensor (pressure drop across the venturi ejector 21: flow of the partial flow), that is to say at least the flow of the partial flow branched off for regeneration is controlled on the basis of these two measurements. In the embodiment according to fig. 2 and 3, the first control signal 101 is further determined based on the temperature sensors T1 to T7 and based on the pressure dew point sensor "PDP". According to an alternative embodiment, one or more of these temperature sensors and the pressure dew point sensor may be provided in the compressor device according to fig. 1, and/or the control unit 100 may be further arranged for determining the application of the second control signal and/or the third control signal for the rotational speed of the drum relative to the rotational symmetry of the pressure vessel and/or the one or more cooling means (similar to fig. 4 and 5), and/or other control signals.
In the embodiments according to fig. 4 and 5, the control unit may be arranged for determining and applying the first control signal 101, the second control signal 102 and/or the at least one third control signal 103, 104, 105. These control signals are determined by the control unit based on one or more measured values from the following sensors: RPM sensor (compressor RPM: supply flow of compressed gas), dP21 (pressure drop across the Venturi ejector 21: flow split), dPREG(the outlet side of the drying zone 12 and the regeneration zone13 pressure drop between inlet sides), dPHEhot(pressure drop in main flow across heat exchanger 64), dPHEcold(pressure drop in the split across heat exchanger 64), one or more of T1 through T8, pressure dew point sensor PDP.
In further embodiments (not shown), the control unit 100 may further be communicatively connected to a remote computer system, e.g. for remote monitoring, control, adjustment and/or software updating, etc.
Fig. 6 shows details of the control of the controllable device according to an embodiment of the invention, in this case a venturi ejector 21 with a controllable opening. In this embodiment, the venturi ejector has a controllable opening driven by a drive rod with a gear drive 121. The pressure drop caused by the controllable openings in the main flow 18 of gas to be dried is shown measured by means of pressure sensors P1 and P2 communicating with the control unit 100. The control unit 100 determines on the basis of this a first control signal 101 to be applied to the driver 121. By changing the position of the controllable opening, the pressure drop, and thus the suction to which the partial flow 19 for regeneration is subjected, changes. In this way, the flow of the split stream for regeneration is controlled.
As described above, in each of the embodiments according to fig. 1 to 5, the drive device 114 is provided to rotate the drum 14 relative to the rotationally symmetrical portion of the pressure vessel 11. The drive means may comprise a motor, preferably an electric motor, preferably with a start/stop controller, and is preferably controlled by a second control signal 102 from the control unit 100.
The start/stop controller is arranged to switch the motor on and off, thereby providing an adjustable average rotational speed of the drum relative to the rotational symmetry. More specifically, the start/stop controller is provided for switching the motor on and off during a preferably continuous operation of the dryer, wherein on the one hand a continuous flow of compressed gas is supplied to the drying zone and dried in the drying zone, and on the other hand a continuous (partial) flow of compressed gas to be dried is led to the regeneration zone for regenerating the drying agent. The start/stop controller is economically more advantageous than a frequency control for adjusting the rotational speed of the electric motor, and thus may provide cost savings in terms of investment costs. Furthermore, the start/stop controller is less complex and requires less control electronics. In particular, the start/stop controller only needs to switch the motor on and off according to a desired duty cycle (in terms of on/off ratio) in order to provide a desired average rotational speed of the drum. In addition, the start/stop controller may rotate the drum in stages relative to the rotational symmetry, for example, to precisely move a section corresponding to the size of the regeneration zone (or a portion thereof) each time, and then stop the movement of that section for a given period of time. Another advantage of the start/stop controller is that the range of average rotational speeds is wider than when frequency control is employed; in particular, the average rotational speed may be adjusted from 0 to the maximum speed of the motor.
Fig. 7A and 7B illustrate some examples of start/stop controllers. In FIG. 7A the average speed is the maximum motor speed vmax1/3, the average speed in FIG. 7B is the motor maximum speed vmax2/3 of (1). The duty cycle has a period T. The average speed can be varied by varying the time the motor is on during the period T. The average speed can also be varied by keeping the time the motor is on constant and varying the time the motor is off, which means that the length of the duty cycle T is variable.
Application example:
in a first application, the exemplary embodiments of the invention described herein may be applied as follows. A relatively high temperature and saturated gas, such as air, is supplied to the inlet 15 for the gas to be dried. The gas being at a relatively high temperature T1 means that it has a relatively high moisture content, so the drying drum 14 needs to remove more moisture from the gas, which in turn means that more regeneration is required and therefore a higher flow rate of regeneration gas is required. By measuring the temperature T1, which may vary, for example, according to the ambient temperature of the compressor installation, a measure of the moisture load of the gas supplied to the inlet 15 can be derived. The control unit 100 controls the flow rate of the regeneration flow (split flow for regeneration) according to T1; specifically, as T1 increases, the control unit increases the flow rate, for example, according to a predetermined table or characteristic control curve. Normal operation of the dryer is monitored by feedback provided by measurement of a pressure dew point sensor "PDP" at outlet 16.
In a second application, the exemplary embodiments of the invention described herein may be applied as follows. If the flow rate of the regeneration flow varies (e.g. in order to keep the pressure dew point PDP stable or within a certain range, or varies in dependence on pressure fluctuations), it is preferable to adjust the cooling of the outgoing regeneration flow 19 and/or to adjust the rotational speed of the drum 14 in dependence on the flow rate of the regeneration flow. By measuring the pressure drop across the venturi ejector 21, a measure of the regeneration flow rate can be obtained. The control unit may, for example, control the flow rate of the cooling water flowing through the cooling device 20 for cooling the outgoing regeneration flow, or may control the flow rate of the cooling water flowing through the cooling device 91 for cooling the confluence (supply flow of the regeneration flow and the gas to be dried) so that more cooling is performed when the regeneration flow increases, thereby avoiding a situation where too little cooling is caused by an increase in the regeneration flow rate. In conjunction with this or independently of this, the control unit 100 can control the rotational speed of the drum 14 according to the regeneration flow rate to optimize the ratio between each other. In this way, the control unit may take into account the lifetime of the desiccant and may adjust the drum speed to accommodate the reduced regeneration and/or absorption capacity of the desiccant.
Claims (12)
1. A dryer (10; 30; 50; 70; 90) for compressed gas, comprising:
a pressure vessel (11) comprising a rotational symmetry section in which there is a drying zone (12) and a regeneration zone (13);
a drum (14) arranged in the rotationally symmetric portion, the drum being provided with a regenerable desiccant;
drive means (114) for rotating the drum relative to the rotational symmetry or vice versa, so that the desiccant moves successively through the drying zone and the regeneration zone;
an inlet (15) for supplying a compressed gas to be dried; and
an outlet (16) for discharging the dried compressed gas;
characterized in that the drive means (114) comprise a motor provided with a start/stop control.
2. Dryer (10; 30; 50; 70; 90) according to claim 1, characterized in that the motor is an electric motor.
3. Dryer (10; 30; 50; 70; 90) according to claim 2, characterized in that the start/stop control is arranged for switching the motor on and off so that the motor can be switched between a maximum rotational speed of the motor and a stopped state.
4. The dryer (10; 30; 50; 70; 90) according to claim 1, characterized in that it further comprises: a set of sensors having at least one sensor (RPM, dPx, Tx, PDP) arranged to measure at least one measurement value related to the operation of the dryer; and a control unit (100) communicatively connected to the at least one sensor and the start/stop controller, and arranged to process the at least one measurement value to determine a control signal (102) for controlling the start/stop controller based on the at least one measurement value and to apply the control signal to the start/stop controller.
5. The dryer (10; 30; 50; 70; 90) according to claim 4, characterized in that said set of sensors comprises one or more sensors (RPM, dPx) for directly or indirectly measuring a supply flow rate and/or a tapped flow rate; and the control unit (100) is arranged to evaluate the directly or indirectly measured supply flow rate and/or the shunt flow rate and to apply the control signal (102) based on the evaluation.
6. The dryer (10; 30; 50; 70; 90) according to claim 4, characterized in that said set of sensors comprises one or more of the following sensors: a rotational speed sensor (RPM) for measuring a rotational speed of a compressor (60) supplying the supply flow; a pressure sensor (dP21) for measuring a pressure drop across the controllable device (21, 121), the controllable device (21, 121) being adapted to merge the gas flow for regeneration with the supply flow of compressed gas to be dried.
7. The dryer (10; 30; 50; 70; 90) according to claim 4, characterized in that said set of sensors comprises one or more of the following sensors: temperature sensors (T3, T4) for measuring the temperature difference between the inlet side and the outlet side of the regeneration zone; temperature sensors (T1, T2) for measuring the temperature difference between the inlet side and the outlet side of the drying zone; and a pressure dew point sensor (PDP) at the outlet (16) for measuring the pressure dew point of the dried compressed gas effluent stream.
8. Drier (10; 30; 50; 70; 90) according to claim 4, characterized in that it comprises a first connection line (17; 51; 77; 97) for branching off a partial flow of the dried compressed gas and directing it to the regeneration zone; the first connection line (77; 97) is provided with a heat exchanger (64) for heating a partial flow branched off for regeneration by the compressed gas to be dried supplied to the dryer; and the set of sensors includes one or more of the following sensors: pressure sensor (dP) for measuring the pressure difference between the outlet side of the drying zone and the inlet side of the regeneration zoneREG) (ii) a And a pressure sensor (dP) for measuring the pressure drop caused by the heat exchanger in the partial flow and/or in the supply flowHEhot、dPHEcold)。
9. Drier (10; 30; 50; 70; 90) according to claim 4, characterised in that it comprises at least one cooling device (20; 65; 91) arranged for cooling the supply flow of compressed gas, and/or the flow of gas for regeneration, and/or the combined flow; and, the set of sensors includes one or more of the following sensors: temperature sensors for measuring the temperature of the respective streams upstream and/or downstream of the respective cooling devices; a pressure sensor for measuring the pressure drop in the relevant flow caused by the respective cooling device; and a temperature sensor for measuring the temperature of the coolant for cooling upstream and/or downstream of the cooling device.
10. Compressor installation comprising a compressor and further comprising a dryer (10; 30; 50; 70; 90) according to any of the preceding claims.
11. A method for drying compressed gas, which method uses a dryer (10; 30; 50; 70; 90) comprising a pressure vessel, which comprises a rotational symmetry with a drying zone (12) and a regeneration zone (13) therein, and a drum (14) provided in the pressure vessel, which drum is provided with a regenerable drying agent, which method comprises the steps of:
rotating the drum relative to the rotational symmetry or the rotational symmetry relative to the drum by a drive (114) such that the desiccant moves through the drying zone and the regeneration zone in succession;
supplying compressed gas to be dried via an inlet (15) connected to the inlet side of the drying zone of the pressure vessel;
discharging the dried compressed gas via an outlet (16) connected to the outlet side of the drying zone of the pressure vessel; and
supplying a gas stream to a regeneration zone for regenerating the desiccant and withdrawing the gas stream from the regeneration zone;
characterized in that the drive means (114) comprise a motor provided with a start/stop controller which periodically turns the motor on and off according to a duty cycle.
12. Method according to claim 11, characterized in that a start/stop control is used for switching the motor on and off during continuous operation of the dryer, wherein on the one hand a continuous flow of compressed gas is supplied to the drying zone and dried in the drying zone and on the other hand a continuous partial flow of compressed gas to be dried or compressed gas after drying is conducted to the regeneration zone for regenerating the drying agent.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BE20195535A BE1027504B1 (en) | 2019-08-16 | 2019-08-16 | Dryer for compressed gas, compressor installation equipped with dryer and method for drying compressed gas |
| BE2019/5535 | 2019-08-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112387084A true CN112387084A (en) | 2021-02-23 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202020154647.0U Active CN212492278U (en) | 2019-08-16 | 2020-02-06 | Dryer for compressed gas and compressor installation |
| CN202010081447.1A Pending CN112387084A (en) | 2019-08-16 | 2020-02-06 | Dryer for compressed gas, compressor installation and method for drying compressed gas |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202020154647.0U Active CN212492278U (en) | 2019-08-16 | 2020-02-06 | Dryer for compressed gas and compressor installation |
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| BE1030810A1 (en) * | 2022-09-12 | 2024-03-19 | Atlas Copco Airpower Nv | FREE AIR SUPPLY (FAD) DRYER CONTROL SYSTEM AND OPERATING METHOD |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| SE365720B (en) * | 1971-08-06 | 1974-04-01 | Atlas Copco Ab | |
| JP2002263434A (en) * | 2001-03-09 | 2002-09-17 | Osaka Gas Co Ltd | Dehumidifier |
| JP2004020109A (en) * | 2002-06-18 | 2004-01-22 | Matsushita Electric Ind Co Ltd | Humidifier and air conditioning machine using the same |
| JP4122346B2 (en) * | 2005-05-12 | 2008-07-23 | 株式会社西部技研 | Dehumidifying air conditioner |
| EP2845638B1 (en) * | 2013-09-09 | 2018-08-22 | Kaeser Kompressoren Se | Method for operating an adsorbing device, and control device |
| DE202014007507U1 (en) | 2013-09-18 | 2014-12-12 | Atlas Copco Airpower N.V. | Dryer for compressed gas and compressor unit equipped with a dryer |
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- 2020-02-06 CN CN202020154647.0U patent/CN212492278U/en active Active
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| CN212492278U (en) | 2021-02-09 |
| BE1027504B1 (en) | 2021-03-15 |
| BE1027504A1 (en) | 2021-03-10 |
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