Patent Publication Number: US-2023142828-A1

Title: Device and method for the adsorption of a gas from a gas mixture to be treated

Description:
FIELD OF THE INVENTION 
     The present invention relates to a device for the adsorption of a gas from a gas mixture to be treated. 
     This gas may be compressed gas from a compressor installation, for example. 
     The gas that is adsorbed may also be water vapor, for example, so the device is essentially a dryer. 
     BACKGROUND OF THE INVENTION 
     More specifically, the invention relates to a device for the adsorption of a gas from a gas mixture to be treated that is provided with an inlet for gas to be dried and an outlet for dried gas, whereby the dryer includes at least two vessels filled with a regenerable adsorbent and an adjustable valve system connecting the aforementioned inlet and outlet to the aforementioned vessels, whereby the adjustable valve system is regulated as such that at least one vessel will treat compressed gas, while the other vessel is successively regenerated and cooled, whereby, by adjusting the valve system, the vessels will each in turn treat compressed gas. 
     Regenerable adsorbent means an adsorbent or desiccant that can adsorb gas from a gas mixture by adsorption and, when saturated with gas, can be regenerated by transmitting a so-called regeneration gas through it. The regeneration gas in this case is, for example, a high-pressure gas that is expanded through a nozzle, expansion valve, or the like. 
     When a vessel treats a gas mixture, it will adsorb a gas from the gas mixture to be treated, saturating the drying agent. 
     This vessel is then regenerated, typically by passing dried compressed air through it, which is expanded via a nozzle, expansion valve, or the like. This gas will extract the adsorbed gas from the adsorbent and thus regenerate it. 
     The vessel can then be cooled before being used again to treat compressed gas. 
     Such types of devices are already known, where the adjustable valve system is used to switch the vessels between treatment and regeneration/cooling. 
     Because of the geometry of the device in general and of the vessels in particular, it is obvious to implement the adjustable valve system in two so-called valve blocks, one of which connects the aforementioned inlet and the second of which connects the aforementioned outlet to the aforementioned vessels. 
     Hereby, one valve block is fitted at the bottom of the vessels and one valve block is fitted on top of the vessels. 
     Such well-known devices with an adjustable valve system with two separate valve blocks to enabling switching of the vessels, have the advantage that they are relatively compact because all kinds of channels, conduits, and valves are grouped in the two valve blocks. 
     For small devices, i.e. with a drying agent volume of around 10 liters, such a valve system still takes up a lot of space compared to the effective drying agent. 
     Moreover, for small devices it is even more important that they are very compact, since in most cases they are used for applications where there is not much space or where one does not want to spend a lot of space on the dryer. 
     But also for other, larger devices it is advantageous to design the valve system as small as possible, as this is associated with lower material costs and lower weight. 
     US 2014/013956 A1 discloses a device for the adsorption of a gas from a gas mixture. 
     US 2005/188848 A1 discloses a device for the adsorption of a gas from a gas mixture. 
     SUMMARY OF THE INVENTION 
     The aim of the present invention is to provide a device with a very compact valve system. 
     To this aim, the invention concerns a device for the adsorption of a gas from a gas mixture, with an inlet for a gas mixture to be treated and an outlet for treated gas, which device comprises at least two vessels filled with a regenerable adsorbent and an adjustable valve system connecting the aforementioned inlet and outlet to the aforementioned vessels, whereby the adjustable valve system is regulated such that at least one vessel will treat compressed gas, while the other vessel is successively regenerated and cooled, whereby, by regulation of the valve system, the vessels will each in turn treat compressed gas, characterized in that the adjustable valve system is combined into a single valve block. 
     The term ‘vessel’ should be interpreted broadly here. The vessel in itself need not be a separate component of the device but may also be realized as a cavity in an enclosure, whereby this cavity contains the desiccant, in the form of what will be called desiccant core. 
     An advantage is that by bringing the adjustable valve system together in a single valve block, it can be made very compact. 
     Furthermore, less material is needed to manufacture the valve block and the amount of electrical and/or pneumatic piping can be greatly reduced too because, unlike in the known dryers with each valve block equipped with the necessary valves, now valves can be combined. 
     This has the added advantage of making the device cheaper and lighter. 
     In the most preferred embodiment, the vessels are provided with two gas accesses, which are located adjacent to each other or at the same end of the vessel and which are arranged in such a way that gas entering the vessel through one access can only leave the vessel through the other access after passing through the adsorbent. 
     This has the advantage that the aforementioned accesses are on the same side or end of the vessel, so the valve block can be placed on this side or end of the vessel. 
     Indeed, by placing the accesses next to each other, the adjustable valve system can be executed as a single valve block. 
     In order to ensure that gas that enters the vessel through one access can only leave the vessel through the other access after passing through the adsorbent, several measures can be taken. 
     Preferably, this is achieved by connecting to one of the aforementioned passages a conduit, tube, or the like extending into the vessel and through the adsorbent. 
     Thus, to exit the vessel through this access with tube, the gas must pass through the adsorbent (or a part thereof) or, conversely, after the gas has entered through this passage with tube, it will first have to pass through the adsorbent (or a part thereof) to exit the vessel through the other access. 
     It is also possible that this will be achieved by other means. For example, if the vessels are realized by a cavity in the housing of the device, one can place in this cavity a bulkhead or the like with an access on each side of the bulkhead. 
     In a practical embodiment, this is the valve block provided with: 
     one or more control valves; 
     a supply channel running from the inlet to the aforementioned control valves; 
     an outlet channel running from the vessels to the outlet; 
     a blow-off channel leading from the aforementioned control valves to a blow-off opening; 
     a regeneration channel which runs from the outlet channel to the vessels. 
     Due to the design or layout of the valve block, in most cases it is the case that the aforementioned channels (or a part thereof) coincide, or that after switching the vessels, two channels switch their function, for example. 
     Preferably, the control valves comprise either two 3/2 valves or one 5/2 valve. Of course, the invention is not limited to this. 
     The invention also relates to a method for adsorbing a gas from a gas mixture to be treated, using a device having an inlet for gas to be treated and an outlet for treated gas, which device comprises at least two vessels filled with a regenerable adsorbent, using an adjustable valve system connecting said inlet and outlet to said vessels, whereby the method includes the step of arranging the adjustable valve system such that at least one vessel will treat compressed gas while the other vessel is regenerated, the vessels each successively treating compressed gas in turn, characterized in that the method includes the step of combining the adjustable valve system into a single valve block. 
     In the most preferred variant, the method further comprises the following steps: 
     providing both vessels with two accesses located side by side or at the same end of the vessel, 
     passing the gas through the vessels in such a way that the gas enters the vessel through one access and can only leave the vessel through the other access after passing through the adsorbent. 
     In a practical embodiment, the method includes the step of connecting a conduit, tube, or the like to one of the aforementioned passages extending into the vessel and through the drying agent. 
     Preferably, the method includes the step of switching the vessels every ten to thirty seconds between adsorption and regeneration. 
     It should be understood that the method according to the invention has the same advantages as the device according to the invention for adsorbing a gas from a gas mixture to be treated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To better demonstrate the characteristics of the invention, the following describes, by way of example without any restrictive character, a number of preferred embodiments of a device and method for the adsorption of a gas from a gas mixture to be treated in accordance with the invention, with reference to the accompanying drawings, in which: 
         FIG.  1    schematically shows an arrangement in accordance with the invention; 
         FIG.  2    shows an alternative of  FIG.  1   ; 
         FIG.  3    shows another alternative embodiment of  FIG.  1   . 
         FIGS.  4  to  8    show a practical embodiment of the device in  FIG.  1   ; 
         FIGS.  9  to  12    show a different practical embodiment of the device in  FIG.  1   . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The device according to the invention for adsorbing a gas from a gas mixture to be treated, shown schematically in  FIG.  1   , will, in this case, adsorb water vapor from a gas. 
     In other words, the device is a dryer  1 . 
     The dryer  1  according to the invention mainly comprises an inlet  2  for gas to be dried, an outlet  3  for dried gas, two vessels  4   a,    4   b  with a regenerable adsorbent  5  and an adjustable valve system  6 . 
     Since this is a dryer  1 , in what follows, the adsorbent  5  will also be called drying agent  5 . 
     In this case, the vessels  4   a,    4   b  are realized in the housing  7  of the dryer  1 , more particularly by means of a casting  8  specially provided for this purpose, which is attached to the rest of the housing  7  of the dryer  1 . 
     In this casting  8 , two cavities  9  or spaces are provided in which the regenerable drying agent  5  or desiccant is introduced. 
     By attaching the casting  8  to the rest of the housing  7 , the vessels  4   a,    4   b  are created which are separated from each other. This means that gas cannot flow from one vessel  4   a  to the other vessel  4   b.    
     Each vessel,  4   a,    4   b,  is provided with two accesses,  10   a,    10   b,  for gas, which are located adjacent to each other or at the same end of the vessel  4   a,    4   b,  in the illustrated example. 
     The design is such that gas entering the vessel  4   a,    4   b  through one access  10   a  can only leave the vessel  4   a,    4   b  through the other access  10   b  after passing through the drying agent  5 . 
     To this end, bulkheads  11  or partitions are provided in the vessels  4   a,    4   b  between both accesses  10   a,    10   b.    
     As can be seen from the figure, the gas entering the vessel  4   a,    4   b  through one access  10   a  must always flow through the drying agent  5  before the gas can leave the vessel  4   a,    4   b  through the other access  10   b.    
     Although in the example shown drying agent  5  is only present on one side of the bulkhead  11 , it is not ruled out that drying agent  5  is present on both sides of the bulkhead  11 , i.e. the aforementioned cavities  9  or spaces are completely filled with drying agent  5 . 
     The drying agent  5  contained in the vessels  4   a,    4   b  is, in this case, a ceramic drying agent  5 . Of course, the invention is not limited to this. 
     The adsorbent  5  or drying agent  5  preferably has a solid form, whereby it comprises a solid support made of ceramic material, paper, fiberglass or wire mesh. 
     The drying agent  5  further takes the form of granules held together in sieves or grilles not shown in the figures. This has the advantage that the drying agent  5  is, as it were, fixed in the vessels  4   a,    4   b  and that the orientation of the dryer  1  plays no role in principle. 
     According to the invention, the adjustable valve system  6  comprises one and only one valve block  12 . 
     By means of this valve block  12 , the aforementioned inlet  2  and outlet  3  will be connected to the vessels  4   a,    4   b.    
     As is known, the adjustable valve system  6  is such that one vessel  4   a  will dry compressed gas, while the other vessel  4   b  is successively regenerated and cooled, whereby by adjusting the valve system  6 , the vessels  4   a,    4   b  each in turn successively dry compressed gas. 
     The valve block  12  in the example shown is provided with: 
     one or more control valves  13 ; 
     a supply channel  14  that runs from the inlet  2  to the aforementioned control valves  13 ; 
     an outlet channel  15  running from the vessels  4   a,    4   b  to the outlet  3 ; 
     a blow-off channel  16  extending from the aforementioned control valves  13  to a blow-off opening  17 ; 
     a regeneration channel  18  which runs from the outlet channel  15  to the vessels  4   a,    4   b.    
     A portion of some of these channels  14 ,  15 ,  16 , and  18  coincide or switch functions, primarily a result of the switching of vessels  4   a,    4   b  between the drying and regeneration phases. 
     In the illustrated example, the valve block  12  is provided with two check valves  19  in the outlet channel  15 . 
     A check valve  19  is provided for each vessel  4   a,    4   b.  Of course, this need not necessarily be a check valve  19 , but the vessels  4   a,    4   b  may be provided with another type of outlet valve. 
     Further, the valve block  12  includes as control valves  13  two 3/2 valves  13   a,  which will control the switching of the vessels  4   a,    4   b.    
     It is also possible to use one 5/2 valve  13   b  instead of two 3/2 valves  13   a.  This is shown in  FIG.  2   . The embodiment of  FIG.  2    is otherwise identical to that of  FIG.  1   . 
     Further, the regeneration channel  18  in this case includes a throttling valve  20  to control the amount of gas passing through it. 
     In  FIG.  1   , two choke valves  20  are provided, which is more practical or space-saving in some cases, in  FIG.  2    one choke valve  20 . 
     Further, a muffler  21  is connected to the outlet of the blow-off channel  16  or, thus, to the blow-off opening  17 . It may also be integrated into the valve block  12 . 
     In addition, the valve block  12  is further provided with a control  22  or control unit for controlling the 3/2 valves  13   a  and with a dew point sensor  23 , both of which can also be integrated into the valve block  12 . 
     The dew point sensor  23  may also be a humidity sensor, pressure sensor, and/or temperature sensor. When the device  1  is not a dryer  1  but a gas separation device, it may also be a sensor of gas quality with respect to oxygen, carbon dioxide, or volatile organic compounds. 
     Moreover, it is not ruled out that the valve block  12  is further provided with cooling fins or the like. 
     The operation of the dryer  1  is very simple and as follows. 
     During the operation of the dryer  1 , gas to be dried, for example compressed gas from a compressor, is supplied through the inlet  2  and conveyed to the control valves  13  through the supply channel  14 . 
     Through the control valves  13 , it is conveyed to the vessel  4   a  which dries gas. In the case of  FIGS.  1  and  2   , this is the left-hand vessel  4   a.    
     The gas will pass through the drying agent  5  and be dried, after which it will exit the dryer  1  by reversal along the bulkhead  11  through the access  10   a  and then through the outlet channel  15 . 
     The regeneration channel  18  will branch off a portion of the dried gas as regeneration gas and bring it to the control valves  13 , after which this regeneration gas will enter the vessel  4   b  being regenerated. In the case of  FIGS.  1  and  2   , this is the right-hand vessel  4   b.    
     After passing through this vessel  4   b,  whereby the gas must again reverse through the bulkhead  11  and is thus, as it were, forced to pass through the drying agent, the gas will exit the dryer  1  through the blow-off channel  16  and the silencer  21 . 
     When the drying agent in the left-hand vessel  4   a  is completely saturated, the two control valves  13  will switch, as is known, and the function of the vessels  4   a,    4   b  will also be switched. 
     To this end, control  22  or controller will appropriately control the control valves  13  based, among other things, on the measurements of the dew point sensor  23 . 
     The controller or control  22  of the valve system  6  will switch the vessels  4   a,    4   b,  in the case of a small dryer  1 , between drying and regeneration every ten to thirty seconds. It is also possible that the switchover occurs after a few minutes. 
     The exact changeover time depends on dryer  1  to dryer  1  and on the ambient conditions and the amount of active drying agent. 
     The left-hand vessel  4   a  will be regenerated after switching, while the right-hand vessel  4   b  will dry, whereby the entire method as described above repeats itself. 
     Working with two vessels  4   a,    4   b  will ensure a continuous flow of dried gas. 
     As shown in  FIGS.  1  and  2   , during operation of the dryer  1  in this case, and preferably, the valve block  12  is located underneath vessels  4   a,    4   b.    
     This has the advantage that any condensate that may occur can easily drain through the blow-off channel  16 . 
     It should be understood that the aforementioned blow-off channel  16  is optional. 
       FIG.  3    shows a variant of the vessels of  FIGS.  1  and  2   , whereby in this case the one vessel  4   a  is executed as a cylinder and the other vessel  4   b  is executed as a hollow cylinder which is coaxially placed around the aforementioned one vessel  4   a.    
     Solid arrangement is space-saving. 
     Also, the bulkheads  11  are replaced by connecting to one of the aforementioned passages  10   a  a conduit  24 , tube, or the like extending into the vessel  4   a,    4   b  and through the drying agent  5 . 
     By such conduit  24 , tube or the like, the gas entering the vessel  4   a,    4   b  through the one access  10   a  will only be able to exit the vessel  4   a,    4   b  through the other access  10   b  after passing through the drying agent  5 . 
     Moreover, it cannot be ruled out that the conduit  24 , tube or the like also contains drying agent  5 . 
       FIGS.  4  to  8    show some views and cross-sections of a practical embodiment of a dryer  1  according to the invention, with indication of the relevant components and channels. 
     In this case, the drying agent  5  is block or beam-shaped. However, the shape of the drying agent  5  is not limiting for this design. 
     Also, one of the passages  10   a  of the vessels  4   a,    4   b  containing drying agent  5  is located centrally under the vessels  4   a,    4   b.  Connected to this is a conduit  24 , tube, or the like, which thus runs centrally through the drying agent  5 . 
       FIGS.  9  to  12    show another practical embodiment, in this case the drying agent  5  takes the form of a cylinder. 
     Note that in this embodiment, unlike in  FIGS.  4  to  8   , the valve block  12  is located above the drying agent  5 . However, if a solid drying agent  5  is used or if granules of drying agent  5  are fixed in sieves or grilles, the orientation of the dryer  1  is not a factor. 
     Although the examples described and shown above each involve only two vessels  4   a,    4   b,  it is not ruled out that there are more than three vessels  4   a,    4   b,  whereby these vessels  4   a,    4   b  are stacked on top of each other two by two. 
     The vessels  4   a,    4   b  can then be connected in series two by two. Alternatively, the cycle of each vessel  4   a,    4   b  may have been shifted over time and a control valve  13  and a check valve  19  may have been provided for each vessel  4   a,    4   b.    
     The present invention is by no means limited to the embodiments described as examples and shown in the figures, but a device and method for adsorbing a gas from a gas mixture to be treated according to the invention can be implemented in all shapes and sizes without going beyond the scope of the invention.