DE19735397A1 - Reactor for the adsorptive separation of a gas mixture - Google Patents

Abstract

Use of a cylindrical reactor for adsorptive separation of a gas mixture is claimed. The reactor contains granular material in an envelope constructed as two concentric cylinders, where the outer cylinder is separated by a small gap from reactor wall. Similarly there is a gap between the inner cylinder and a core tube. Both gaps are used for gas supply and removal. The top end of the reactor, and the envelope, is domed. The axis of the reactor is vertical and the reaction material envelope rests on a solid baseplate.

Description

The invention relates to the use of a reactor which is essentially constructed in a cylinder-symmetrical manner about an essentially vertical axis is, a coat and within the coat a bed, which with at least a pourable material is filled and by an inner and an outer Basket as well as on its underside is delimited by a floor in which both between the outer basket and the jacket as well as within the inner basket Gas supply or gas discharge areas are formed and the bed over almost its entire length is ring-shaped and dome-shaped in its upper area is trained.

A reactor of the type described at the beginning, for chemical reactions, at where gases or fluid media are brought into contact with a solid bed e.g. B. from DE-OS 27 42 752 known. The reactor described therein is suitable especially for catalytic reactions, preferably for the dehydrogenation reactions of hydrocarbons, e.g. B. the production of styrene from ethylbenzene.

Such reactors are or have not yet been used for the implementation of Adsorptive separation processes considered. It has been extensive in time Experiments have shown that there are reactors of the type described above excellent for carrying out adsorptive reactions, regardless of whether it is the adsorptive reactions are pressure (so-called PSA), vacuum pressure (so-called VPSA process) and / or temperature swing adsorption process (so-called TSA- Process) is suitable.

In principle, such reactors for the adsorptive separation of one or several components from a multi-component mixture, in particular from a multi-component gas mixture, or for the adsorptive separation of a multi-component mixture, in particular a multi-component Gas mixture can be used.  

Examples include the adsorptive separation of nitrogen from a nitrogen containing gas mixture, in particular from air, or the adsorptive separation of Called carbon dioxide from a gas mixture containing carbon dioxide.

Further developing the invention it is proposed that the bed of the reactor with only one adsorbent is filled. By means of this configuration can one refrains from filling the reactor with a second adsorbent can and on the other hand, what is particularly in radial reactors constructive reasons is advantageous on an elaborate support structure for the required partition between the two adsorbents is necessary, to be dispensed with. This leads to a significant reduction in investment costs for such a reactor.

The use of a reactor according to the invention, such as that used for. B. from the above DE-OS 27 42 752 is known, will be explained in more detail with reference to the figure. The figure shows the basic structure of a reactor according to DE-OS 27 42 752. The representation is for the sake of simplicity carried out very schematically, in particular correspond to Relationships between the external dimensions of the reactor and the Material thicknesses are not the real dimensions.

The reactor is essentially cylindrical symmetrical about the vertical axis 1 . It is limited to the outside by a jacket 2 , which has an upper 7 and a lower cap 9 . In the lower cap 9 , inlet openings 10 and outlet openings 11 and 12 are provided for the feed gas (mixture) and for the component or components separated from the gas to be cleaned. The upper cap 7 is broken through by a manhole 8 for filling and / or suctioning free-flowing material.

The adsorption bed 3 , which is delimited by an inner 4 and an outer basket 5 , is arranged in the interior of the reactor. The adsorption bed 3 is closed at the bottom by the bottom 6 , which is generally supported by ribs 17 arranged in a star shape on the lower cap 9 of the jacket 2 . The baskets 4 and 5 are made of mostly perforated sheet metal, which is covered with wire mesh.

The (gas) mixture to be cleaned or disassembled, for example air, flows through the inlet opening 10 into the lower region 13 of the reactor and is formed through the underside of the bottom 6 into the one formed by the jacket 2 and the outer basket 5 Annulus 14 deflected. From there, the gas flows with a radial component through the adsorption bed 3 into the inner annular space 15 . The inner annular space 15 is limited only by the inner basket 4 . The cleaned gas which has flowed into the inner annular space 15 is then withdrawn from the reactor via the outlet opening 11 .

In principle, the direction of flow of the (gas) mixture to be cleaned or dismantled can also be reversed. In this case, the (gas) mixture flows through the opening 11 into the inner annular space 15 and from this with a radial component through the adsorption bed 3 into the annular space 14 formed by the jacket 2 and the outer basket 5 , from which it flows through the Opening 10 is withdrawn from the reactor.

The adsorption bed 3 is ring-shaped over almost its entire length (area A), while it has a hood-shaped shape in its upper area (area B). In addition, the bed 3 points into a manhole 8 arranged at the apex of the upper cap 7 . The part of the adsorption bed 3 that extends into this manhole 8 does not take part in the flow between the feed gas and the adsorption bed 3 at the start of the adsorption activity. However, since the undesirable settlement phenomena of the adsorption bed 3 immediately after the (first) start-up of the reactor, for. B. after the reactor has been refilled with adsorbent material, the part of the bed extending into the manhole 8 drops downward in the course of the settlement phenomena. The subsiding part of the adsorption bed thereby fills the spaces within the bed 3 which are freed up by the settlement. There is therefore no need for further devices to compensate for the settlement phenomena of the adsorbent.

In addition to the opening 10 , the reactor can have a further opening 12 in its lower region. So the (gas) mixture during the adsorption phase of a pressure swing adsorption process z. B. flow through the opening 10 into the reactor or the annular gap 14 , while via the opening 12 , which can also be connected to a vacuum pump, a lowering of the pressure in the adsorption bed 3 can be realized. Of course, instead of the two inlet and outlet openings 10 and 12, only one opening, the entry of the (gas) mixture to be cleaned or disassembled as well as the exit or

Vacuuming the cleaned or disassembled (gas) mixture as well as the separated Components are used.

If the reactor is used in temperature swing adsorption processes, a regeneration gas is passed over the adsorption bed 3 during the regeneration phase. This regeneration gas can be supplied and discharged via the openings 10 , 11 and 12 shown in the figure, but of course further openings which serve to supply and discharge the regeneration gas can also be provided.

As shown in the figure, the reactor is preferably with only one Adsorbent filled. Surprisingly, long-term trials have shown that in certain adsorptive gas separation processes, where previously a second Adsorbent layer z. B. was required to dry the gas stream on the upstream protection zone can be dispensed with. Thus the use of the described reactor also possible for adsorptive separation processes and a structurally complex separating screen between two layers of adsorbent omitted.

However, should a further adsorbent be required for reasons not to be discussed in more detail here, then this must be filled into an annular gap which is formed either by the inner basket 4 and an intermediate basket (not shown in the figure) or by the outer basket 5 and an intermediate basket. However, the provision of such an intermediate basket considerably increases the design effort of the reactor and also makes it more expensive.

Claims (7)

1. Use of a reactor which is essentially cylindrically symmetrical about an im essentially vertical axis is constructed, a jacket and inside of the jacket has a bed which has at least one free-flowing Material is filled by an inner and an outer basket as well its underside is bounded by a floor, in which both between the outer basket and the jacket as well as within the inner basket gas supply or gas discharge areas are formed, and wherein the bed over almost its entire length in a ring shape and dome-shaped in its upper area is trained for adsorptive separation processes. 2. Use of a reactor according to claim 1 for pressure (PSA), vacuum pressure (VPSA) and / or temperature swing adsorption process (TSA). 3. Use of a reactor according to one of the preceding claims for the adsorptive separation of one or more components from one multi-component mixture, in particular from a multi-component Gas mixture. 4. Use of a reactor according to one of the preceding claims for the adsorptive separation of a multi-component mixture, in particular of a multi-component gas mixture. 5. Use of a reactor according to one of the preceding claims for the adsorptive separation of nitrogen from a nitrogen-containing Gas mixture, especially from air. 6. Use of a reactor according to one of the preceding claims for the adsorptive separation of carbon dioxide from a carbon dioxide-containing Gas mixture. 7. Use of a reactor according to any one of the preceding claims the bed is filled with only one adsorbent.