Sorption device and method for the separation of a component from a gas stream

Abstract

A sorption device for the separation of a component from a gas stream comprising - an inlet conduit (4) with a conduit inlet and conduit outlet for the gas stream, whereby the inlet conduit (4) comprises restriction means (9) for restricting a flow of at least part of the gas stream; and - a sorption vessel (2) containing a solid sorption medium (3) for the sorption of the component from the gas stream, whereby the sorption vessel (2) is provided with a vessel inlet which is fluidly connected to the conduit outlet, characterised in that the inlet conduit (4) comprises deactivation means (10) for at least partly deactivating the restriction means (9).

Description

[0001] Sorption device and method for the separation of a component from a gas stream

[0002] The present invention concerns a sorption device and method for the separation of a component from a gas stream .

[0003] More specifically, the invention concerns a sorption device for the separation of a component from a gas stream comprising

[0004] - an inlet conduit with a conduit inlet and conduit outlet for the gas stream, whereby the inlet conduit comprises restriction means for restricting a flow of at least part of the gas stream; and

[0005] - a sorption vessel containing a solid sorption medium for the sorption of the component from the gas stream, whereby the sorption vessel is provided with a vessel inlet which is fluidly connected to the conduit outlet .

[0006] Within the context of the invention, the term "solid sorption medium" should not be interpreted too narrowly : this term may be interpreted as a structured medium of solid sorption material , but also as a medium comprising a loose powder of solid sorption material .

[0007] In the already known prior art , when pressurizing a sorption vessel containing a solid sorption medium with a gas stream flowing upwards through the vessel with respect to a direction of a gravitational force acting on the solid sorption medium, high flow velocities of the gas stream can can result in a loss of

[0008] - lifetime of the solid sorption medium due to fluidization and / or abrasion of the solid sorption medium;

[0009] - performance as they can disturb a mass transfer zone in the solid sorption medium, either pushing the mass transfer zone upwards or dispersing the mass transfer zone due to an uneven flow distribution of the gas stream through the solid sorption medium.

[0010] Existing solutions in the prioar art are :

[0011] 1 . filling the sorption vessel with a packed bed of solid sorption medium:

[0012] Hereby, the solid sorption medium is mechanically pushed down, such that a fluidization velocity of the solid sorption medium increases . However , there are limits on the pressure that can be applied on the solid sorption medium, either due to practical implementation or crushing strength of the solid sorption medium.

[0013] 2 . restricting an inlet flow of the gas stream into the sorption vessel :

[0014] Sometimes a restriction is placed upstream of the sorption vessel to limit a flow rate of the gas stream entering the sorption vessel . However, this can increase the pressure drop over the sorption device significantly .

[0015] 3 . pressurizing the sorption vessel at least partially with backfill :

[0016] To counteract a gravitationally upward gas stream through the solid sorption medium from bottom to top, the sorption vessel is completely or partially pressurized with product gas already produced by the sorption process in the sorption vessel , the product gas flowing from top to bottom . This can only be done if there is suff icient backpressure from the product gas . It also increases pressure instability in a product vessel for storing the product gas at an outlet of the sorption vessel .

[0017] 4 . placing a deactivatable restriction on the outlet of the sorption vessel :

[0018] To prevent a sudden pressurization of downstream vessels , the outlet of the sorption vessel can be restricted with an orifice to slowly build up pressure in the product vessel . When the product vessel has been pressurized, the orifice is bypassed and pressurization of the sorption vessel with backfill can occur . However , even when the outlet is restricted by the orifice , sudden pressurization of the sorption vessel can still cause very high flow velocities of the gas stream through the solid sorption medium.

[0019] The obj ective of the invention is to provide a solution to one or more of the aforementioned and / or other disadvantages . More specifically, the obj ective of the invention is to lower flow velocities of a gas stream through the solid sorption medium during certain steps in the sorption process without increasing a pressure drop over the sorption device during other steps .

[0020] Thereto , the invention relates to a sorption device for the separation of a component from a gas stream comprising - an inlet conduit with a conduit inlet and conduit outlet for the gas stream, whereby the inlet conduit comprises restriction means for restricting a flow of at least part of the gas stream; and

[0021] - a sorption vessel containing a solid sorption medium for the sorption of the component from the gas stream, whereby the sorption vessel is provided with a vessel inlet which is fluidly connected to the conduit outlet , with the characteristic that the inlet conduit comprises deactivation means for at least partly deactivating the restriction means .

[0022] A pressure swing sorption process carried out in the sorption device according to the invention can benefit from a slow pressurization of the sorption vessel , and therefore lower flow velocities of the gas stream through the solid sorption medium without an excessive increase of a pressure drop over the sorption device , either during start-up of the pressurization of the sorption vessel and / or during certain other steps of the pressure swing sorption process .

[0023] In a preferable embodiment of the sorption device according to the invention, the sorption device is provided with a control device for controlling the deactivation means .

[0024] In this way, the deactivation means can be controlled by the control device , possibly in an automatic way and / or in a dynamic way during operation of the sorption device .

[0025] Accordingly, the deactivation means can regulate the operation of the sorption device to a desired operational regime .

[0026] In a practical embodiment of the sorption device according to the invention, the sorption device is an adsorption device , and the sorption vessel is an adsorption vessel containing a solid adsorption medium as solid sorption medium for the adsorption of the component from the gas stream.

[0027] In a next preferable embodiment of the sorption device according to the invention, the restriction means are configured such that a total flow of the gas stream through the inlet conduit can be restricted to a maximally allowable flow .

[0028] In this way, the total flow of the gas stream through the inlet conduit can be restricted in order to limit flow velocities of the gas stream through the solid sorption medium to an allowable level , especially during start-up of the sorption device when there is no backpressure available in a product vessel and / or during another pressurization step of the sorption vessel in every sorption cycle .

[0029] In a more preferable embodiment of the sorption device according to the invention, the restrictions means are configured to be adj ustable such that the maximally allowable flow can be regulated .

[0030] In this way, the restriction means can regulate the operation of the sorption device to a desired operational regime , possibly in a dynamic way during operation of the sorption device .

[0031] In an even more preferable embodiment of the sorption device according to the invention, the inlet conduit is provided with a control unit to adj ust the restriction means .

[0032] In this way, the restriction means can be controlled by the control unit , possibly in an automatic way and / or in a dynamic way during operation of the sorption device .

[0033] In a next practical embodiment of the sorption device according to the invention, the solid sorption medium is a loose powder bed .

[0034] This is possible as the flow velocities of the gas stream through the solid sorption medium can be limited through regulation by the restriction means , such that the flow velocities of the gas stream through the solid sorption medium are lower than a fluidization velocity of the solid sorption medium and accordingly fluidization of the solid sorption medium is avoided . The avoidance of fluidization of the solid sorption medium will increase a lifetime of the solid sorption medium and a performance of the sorption device .

[0035] In a next preferable embodiment of the sorption device according to the invention, the restriction means and deactivation means are configured such that a flow velocity of the gas stream through the solid sorption medium is lower than a fluidization velocity of the solid sorption medium, preferably lower than the fluidization velocity reduced with a positive safety margin .

[0036] In this way, fluidization of the solid sorption medium is avoided . This will increase the lifetime of the solid sorption medium and a performance of the sorption device .

[0037] In a next preferable embodiment of the sorption device according to the invention, the inlet conduit comprises two parallel conduit lines configured to fluidly connect the conduit inlet and the conduit outlet , whereby a first conduit line of the two parallel conduit lines is provided with the restriction means such that a flow of gas through the first conduit line is restricted, and whereby a second conduit line of the two parallel conduit lines is provided with a closable valve , such that the closable valve acts as the deactivation means if switched to an open position .

[0038] When the closable valve is in a closed position, the flow of the gas stream is restricted by the restriction means . In open position, the restriction means are bypassed and pressure drop over the sorption device is reduced .

[0039] Preferably, the two parallel conduit lines are integrated within a common valve housing in order to limit the size of the sorption device . Alternatively, the inlet conduit comprises a conduit line for fluidly connecting the conduit inlet and the conduit outlet , whereby the conduit line includes a valve configured such that a controlled amount of gas can always leak through the valve .

[0040] In this alternative case , the valve can act as both the restriction means and the deactivation means .

[0041] When the valve is switched to a more closed position, it acts more as restriction means and less as deactivation means . When the valve is switched to a more open position, it acts less as restriction means and more as deactivation means .

[0042] The invention also relates to a method for the separation of a component from a gas stream comprising the following steps :

[0043] - guiding the gas stream through an inlet conduit to a sorption vessel containing a solid sorption medium;

[0044] - restricting a flow of at least part of the gas stream in the inlet conduit at a start of said guiding of the gas stream through the inlet conduit ;

[0045] - sorbing the component from the gas stream by means of the solid sorption medium to produce a product gas with a reduced concentration of the component , with the characteristic that the method comprises the step of at least partly deactivating the restricting of said flow when - the gas stream has been guided through the inlet conduit to the sorption vessel for a minimum threshold period; and / or

[0046] - a minimum threshold pressure in the sorption vessel is reached; and / or

[0047] - the product gas is able to provide sufficient backpressure to at least partially fill the sorption vessel with backfill .

[0048] In a preferable embodiment of the method according to the invention, a total flow of the gas stream through the inlet conduit is restricted to a maximally allowable flow at the start of the guiding of the gas stream through the inlet conduit .

[0049] In a next preferable embodiment of the method according to the invention, the solid sorption medium is a loose powder bed, and said restricting and said at least partly deactivating are such that a flow velocity of the gas stream through the solid sorption medium is lower than a fluidization velocity of the solid sorption medium, preferably lower than the fluidization velocity reduced with a positive safety margin .

[0050] It is evident that these embodiments of the method according to the invention exhibit the same advantages as the corresponding embodiments of the sorption device according to the invention as described hereabove .

[0051] With the intention of better showing the characteristics of the invention, a preferred embodiment of a sorption device and method according to the invention is described hereinafter by way of example , without any limiting nature , with reference to the accompanying drawings , wherein : figure 1 shows a first conventional sorption device in which the sorption vessel is filled with a packed bed of solid sorption medium; figure 2 shows another second conventional sorption device in which an inlet flow of the gas stream into the sorption vessel is restricted; figure 3 shows another third conventional sorption device in which the sorption vessel is at least partially filled with backfill ; figure 4 shows another fourth conventional sorption device in which a deactivatable restriction is placed on the outlet of the sorption vessel ; figures 5 and 6 show a sorption device and method according to the invention .

[0052] Figure 1 shows a first conventional sorption device 1 with a sorption vessel 2 containing a packed bed of solid sorption medium 3 .

[0053] A gas stream is drawn in into the sorption vessel 2 through an inlet conduit 4 .

[0054] In the sorption vessel 2 , a component is separated from the gas stream by sorption of this component on the solid sorption medium 3 . After the sorption of the component from the gas stream in the sorpt ion vessel 2 , a resulting product gas stream is sent from the sorption vessel 2 to a product vessel 5 .

[0055] A disadvantage of the packed bed of solid sorption medium 3 in the sorption vessel 2 is a high pressure drop of the gas stream over the packed bed at high flow velocities of the gas stream through the packed bed . Therefore , when starting a pressurization of the sorption vessel 2 , an inlet pressure at an inlet of the inlet conduit 4 is much higher than a pressure in the sorption vessel 2 or in the product vessel 5 . The sorption device 1 might fail because of a high force on the packed bed resulting from this pressure drop, due to an exceeding of either a practical implementation limit or a crushing strength of the solid sorption medium 3 .

[0056] Figure 2 shows another second conventional sorption device 1 in which an inlet flow of the gas stream into the sorption vessel 2 is restricted by a permanent restriction 6 in the inlet conduit 4 .

[0057] This permanent restriction 6 increases the pressure drop over the inlet conduit 4 and therefore the sorption device 1 significantly .

[0058] Figure 3 shows another third conventional sorption device 1 in which the sorption vessel 2 is at least partially filled with backfill from the product vessel 5 .

[0059] However , this filling with backfill is only possible when there is sufficient backpressure from the product gas in the product vessel 5 . It also increases pressure instability in the product vessel 5 .

[0060] Figure 4 shows another fourth conventional sorption device 1 in which a minimum pressure valve 7 is placed on the outlet of the sorption vessel 2 .

[0061] In this case , the outlet of the sorption vessel 2 can be restricted with an orifice 8 to slowly build up pressure in the product vessel 5 to prevent a sudden pressurization of downstream vessels . When the product vessel 5 has been pressurized, the orifice 8 is bypassed by means of the minimum pressure valve 7 and pressurization of the sorption vessel 2 with backfill can occur .

[0062] However , even when the outlet is restricted by the orifice 8 , sudden pressurization of the sorption vessel 2 can still cause very high flow velocities of the gas stream through the solid sorption medium 3 .

[0063] Figures 5 and 6 show a sorption device 1 for the separation of a component from a gas stream according to the invention .

[0064] This sorption device 1 comprises a sorption vessel 2 containing a solid sorption medium 3 , for example a loose powder bed, for the sorption of the component from the gas stream.

[0065] For instance , the sorption device 1 may be an adsorption device , and the sorption vessel 2 may be an adsorption vessel containing a solid adsorption medium as solid sorption medium 3 for the adsorption of the component from the gas stream.

[0066] Furthermore , the sorption device 1 comprises an inlet conduit 4 with a conduit inlet and conduit outlet for the gas stream, whereby the inlet conduit 4 comprises restriction means 9 for restricting a flow of at least part of the gas stream .

[0067] The sorption vessel 2 is provided with a vessel inlet which is fluidly connected to the conduit outlet .

[0068] The restriction means 9 may be configured such that a total flow of the gas stream through the inlet conduit 4 can be restricted to a maximally allowable flow . Hereby, the restriction means 9 may be configured to be adj ustable such that the maximally allowable flow can be regulated . To this purpose , the inlet conduit may be provided with a control unit ( not shown in Figure 5 or 6 ) to adj ust the restriction means 9 .

[0069] The inlet conduit 4 comprises deactivation means 10 for at least partly deactivating the restriction means 9 .

[0070] The sorption device 1 may be provided with a control device ( not shown in Figure 5 or 6 ) for controlling the deactivation means 10 .

[0071] The restriction means 9 and the deactivation means 10 may be configured such that a flow velocity of the gas stream through the solid sorption medium 3 is lower than a fluidization velocity of the solid sorption medium 3 , preferably lower than the fluidization velocity reduced with a positive safety margin . In this way, fluidization of the solid sorption medium 3 can be avoided .

[0072] In this case , the inlet conduit 4 comprises two parallel conduit lines , optionally integrated within a common valve housing (not shown in Figure 5 or 6 ) , configured to fluidly connect the conduit inlet and the conduit outlet , whereby a first conduit line of the two parallel conduit lines is provided with the restriction means 9 such that a flow of gas through the first conduit line is restricted, and whereby a second conduit line of the two parallel conduit lines is provided with a closable valve 11 , such that the closable valve 11 acts as the deactivation means 10 if switched to an open position as illustrated in Figure 6 .

[0073] The closable valve 11 is closed during

[0074] - start-up of the sorption device 1 , when there is no backpressure available in the product vessel 5 ; and / or

[0075] - a pressurization step of the sorption vessel 2 in every sorption cycle , such that a flow of the gas stream through the inlet conduit 4 towards the sorption vessel 2 is restricted and the sorption vessel 2 is pressurized slowly .

[0076] A slower pressurization of the sorption vessel 2 will result in lower flow velocities of the gas stream through the solid sorption medium 3 without causing a high pressure drop over the sorption device 1 . The closable valve 11 is then opened when

[0077] - the gas stream has been guided through the inlet conduit 4 to the sorption vessel 2 for a minimum threshold period; and / or

[0078] - a minimum threshold pressure in the sorption vessel 2 is reached; and / or

[0079] - the product gas in the product vessel 5 is able to provide sufficient backpressure to at least partially fill the sorption vessel 2 with backfill , as illustrated in Figure 6 .

[0080] Alternatively, it is not excluded within the context of the invention that the inlet conduit comprises a conduit line for fluidly connecting the conduit inlet and the conduit outlet whereby the conduit line includes a valve configured such that a controlled amount of gas can always leak through the valve , instead of the two parallel conduit lines as described hereabove .

[0081] A total flow of the gas stream through the inlet conduit 4 may be restricted to a maximally allowable flow at the start of the guiding of the gas stream through the inlet conduit 4 .

[0082] Furthermore , if the solid sorption medium 3 is a loose powder bed, the restricting of the flow of at least part of the gas stream in the inlet conduit 3 and the at least partly deactivating of the restricting of the flow may be such that a flow velocity of the gas stream through the solid sorption medium 3 is lower than a fluidization velocity of the solid sorption medium 3 , preferably lower than the fluidization velocity reduced with a positive safety margin . The present invention is by no means limited to the embodiments described as an example and shown in the drawings , but a sorption device and method according to the invention can be realised in all kinds of variants without departing from the scope of the invention as defined in the claims .

Claims

Claims .1.- A sorption device for the separation of a component from a gas stream comprising- an inlet conduit (4) with a conduit inlet and conduit outlet for the gas stream, whereby the inlet conduit (4) comprises restriction means (9) for restricting a flow of at least part of the gas stream; and- a sorption vessel (2) containing a solid sorption medium (3) for the sorption of the component from the gas stream, whereby the sorption vessel (2) is provided with a vessel inlet which is fluidly connected to the conduit outlet, characterised in that the inlet conduit (4) comprises deactivation means (10) for at least partly deactivating the restriction means (9) .2.- The sorption device according to claim 1, characterised in that the sorption device (1) is provided with a control device for controlling the deactivation means (10) .3.- The sorption device according to claim 1 or 2, characterised in that the sorption device (1) is an adsorption device and the sorption vessel (2) is an adsorption vessel containing a solid adsorption medium as solid sorption medium (3) for the adsorption of the component from the gas stream.4.- The sorption device according to any one of the preceding claims 1 to 3, characterised in that the restriction means (9) are configured such that a total flow of the gas stream through the inlet conduit (4) can be restricted to a maximally allowable flow.5.- The sorption device according to claim 4, characterised in that the restriction means (9) are configured to be adjustable such that the maximally allowable flow can be regulated.6.- The sorption device according to claim 5, characterised in that the inlet conduit (4) is provided with a control unit to adjust the restriction means (9) .7.- The sorption device according to any one of the preceding claims 1 to 6, characterised in that the solid sorption medium (3) is a loose powder bed.8.- The sorption device according to any one of the preceding claims 1 to 7, characterised in that the restriction means (9) and deactivation means (10) are configured such that a flow velocity of the gas stream through the solid sorption medium (3) is lower than a fluidization velocity of the solid sorption medium (3) , preferably lower than the fluidization velocity reduced with a positive safety margin.9.- The sorption device according to any one of the preceding claims 1 to 8, characterised in that the inlet conduit (4) comprises two parallel conduit lines configured to fluidly connect the conduit inlet and the conduit outlet,whereby a first conduit line of the two parallel conduit lines is provided with the restriction means (9) such that a flow of gas through the first conduit line is restricted, and whereby a second conduit line of the two parallel conduit lines is provided with a closable valve (11) , such that the closable valve (11) acts as the deactivation means (10) if switched to an open position.10.- The sorption device according to claim 9, characterised in that the two parallel conduit lines are integrated within a common valve housing.11.- The sorption device according to any one of the preceding claims 1 to 8, characterised in that the inlet conduit (4) comprises a conduit line for fluidly connecting the conduit inlet and the conduit outlet, whereby the conduit line includes a valve configured such that a controlled amount of gas can always leak through the valve .12.- A method for the separation of a component from a gas stream comprising the following steps:- guiding the gas stream through an inlet conduit (4) to a sorption vessel (2) containing a solid sorption medium ( 3 ) ;- restricting a flow of at least part of the gas stream in the inlet conduit (4) at a start of said guiding of the gas stream through the inlet conduit (4) ;- sorbing the component from the gas stream by means of the solid sorption medium (3) to produce a product gas with a reduced concentration of the component, characterised in that the method comprises the step of at least partly deactivating the restricting of said flow when- the gas stream has been guided through the inlet conduit (4) to the sorption vessel (2) for a minimum threshold period; and / or- a minimum threshold pressure in the sorption vessel (2) is reached; and / or- the product gas is able to provide sufficient backpressure to at least partially fill the sorption vessel (2) with backfill.13.- The method according to claim 12, characterised in that a total flow of the gas stream through the inlet conduit (4) is restricted to a maximally allowable flow at the start of the guiding of the gas stream through the inlet conduit (4) .14.- The method according to claim 12 or 13, characterised in that- the solid sorption medium (3) is a loose powder bed; and- said restricting and said at least partly deactivating are such that a flow velocity of the gas stream through the solid sorption medium (3) is lower than a fluidization velocity of the solid sorption medium (3) , preferably lower than the fluidization velocity reduced with a positive safety margin.