DE3631365A1 - Reformer for the catalytic cracking of gaseous hydrocarbons by steam - Google Patents

Abstract

In a reformer for the catalytic cracking of gaseous hydrocarbons in particular by steam, to give a product gas having a pressure vessel (1), a multiplicity of cracking tubes (2) arranged parallel to each other in the vessel and a catalyst (K), convective heat being able to be transported through the tube walls from a hot heating gas to the process gas flowing through the catalyst, on the one hand, to facilitate the catalyst change, it is provided that the heating gas (HG) is conducted through the cracking tubes (2') and the catalyst (K) is introduced into the pressure vessel (1) as a dumped packing between the cracking tubes, and on the other hand, to improve the bracing of the cracking tubes, it is provided that the tubes (2; 2') are supported vertically, together with the catalyst (K) on a floor dome which is made of a ceramic material, borders a gas collection chamber (9) for the product gas (PD) and is furnished with gas through-holes (5b). <IMAGE>

Description

The invention relates to a reformer for the catalytic Splitting of gaseous hydrocarbons, especially with water steam to a product gas with a pressure vessel, one Variety of arranged in parallel in the container neten canned tubes and a catalyst, whereby by the Through the pipe walls, convective heat from a hot heater gas to the process gas flowing through the catalyst is portable.

Such a reformer is known from the prospectus of the applicant "Process Engineering - Steam Reformer and Intermediate Heat Exchanger for PNP or HTR-Module Concept", p. 2, in which the catalyst material is filled into the canned tubes supported in the pressure vessel.

When changing the catalyst, the can must be replaced individually to be pulled. Otherwise, the hanging support tends Pipe bundle to vibrate and the use of the Heat gas supplied is not optimal.

The hanging support of the can in a support plate leads to relatively small reformer units or very heavy support plates due to the tensile loads high operating temperatures.  

It is first the object of the present invention specify a reformer where the catalyst change relieved and at the same time the stability of the tube bundle is improved.

This object is achieved in that the heating gas through the can is guided and the catalyst in the Pressure vessel inserted between the can as a bed is brought.

When changing the catalyst, the pipes do not need to be pulled be, but the catalyst bed in suitable ter way, e.g. B. by suction from the entire volume be removed. By immersing the pipes in the Fill are stabilized.

This subtask is also solved when the gap pipes and the catalyst hanging in the container are supported.

Another object of the present invention is however, also the support of the can in the Druckbe container to improve so that relatively large reformer ten can be built.

This object is achieved in that the pipes are standing on a made of a ceramic material and with a gas collecting space for the product gas Vaulted ceiling vaults along with the Catalyst is supported.

When using a vaulted ceiling from a ceramic factory material that supports the can and the catalyst, is the load transfer of these weights to the pressure vessel extremely cheap. In addition, difference strains largely reduced. The vaulted ceiling can be self-supporting or supported in the middle or several times.  Both hanging and supported Construction of the can, it is possible that the Kata analyzer in a conventional manner in the can is ordered and these are surrounded by the heating gas.

In the reformers according to the invention, the can in a manner known per se as separate individual tubes be educated; however, it could be beneficial if the Canned tubes to fins concentric to the container axis walls are summarized, or as a spiral ge if necessary wrapped fins welded together boards are trained. The use of concentric fin walls or spirally coiled tubes is particularly indicated when the catalyst is loose Fill should be introduced between the can. The use of spirally coiled tubes can an undesirable sagging (setting) of the catalyst prevent.

The can can be assigned over their lower ends Collector to be supported on the vaulted ceiling. For construction and operation of the system, it seems more appropriate that the standing canned pipes over a distribution layer supported from distributor stones on the vaulted ceiling are, the distributor stones under certain circumstances immediately the vaulted ceilings can be.

To deal with such a distribution layer that over one or introduced a small number of gas supply channels To be able to distribute gases is preferably provided that the distributor stones are designed so that they at Ne a flat and one after the other Side of the layer essentially gas-tight and closed provided with gas distribution openings on its upper side Build gas distribution network, and that on the distribution layer of standing pipes with gas pipes reach through the distributor stones.  

When the heating gas is filled with catalyst and from the process gas flowing through canned tubes, it can lead to verbes Heat transfer should be expedient that the gap pipes at a relatively short distance from a conc trical cladding tube are surrounded by the heating gas flows while outside did not flow through the cladding Dead spaces are formed in the area of the reformer.

If the heat content of the heating gas after leaving the Area of the pressure vessel in which the can is attached are arranged, is still sufficiently high, others can Means for heat dissipation may be provided.

For one, the facilities can be made by separate pipe windings are formed at the ends of the can. It However, it is also possible to reformer the Ab in the container flow of the product gas a separate and in one other heat carrier circuit switched on heat exchanger, especially to assign helix heat exchangers.

Before the description of various embodiments of the reformer according to the invention, it is pointed out that a reformer is known from the journal "Hydrocarbon Processing", June 1982, pp. 101-105, in particular Fig. 1, which has a large number of gap tubes filled with primary catalyst material , which are arranged at a large distance from each other in a rectangular chamber and which are heated by ceiling burners, however, in contrast to the first-mentioned literature, flow through the can without deflection, ie are equipped with open can at the lower end.

The invention will now be described with reference to the accompanying figures are explained in more detail. It shows:

Fig. 1 shows a schematic longitudinal section through a first embodiment of a reformer, wherein the gap pipes are collectors on a ceramic vault supported,

Fig. 2 shows an embodiment of the cracking tubes,

Fig. 3a and 3b show a further embodiment,

Fig. 4 shows a longitudinal section through a reformer directly supported on a distribution layer of ceramic shaped bricks cracking tubes,

Fig. 5 is a partial section for explaining the pipe windings provided at the upper end of the can, which preferably lead to external collectors, and serve to compensate for expansion and at the same time use the waste heat.

Figure 6 divider stones. A section through a plurality of composite Ver,

Fig. 7 is a section along the line VII-VII in Fig. 6

Fig. 8 shows a section through a distribution modified forms of distribution blocks,

Fig. 9 is a longitudinal section through a reformer with hän constricting cracking tubes and a catalyst bed between the cracking tubes,

Fig. 10 is a longitudinal section through a reformer with hanging pipes, which are filled with catalyst, and

Fig. 11 is a partial section through a reformer comparable bar Fig. 5, wherein above the reformer from a heat heating surface in the same pressure vessel is arranged.

In the embodiment according to FIG. 1, the in a standing pressure vessel ( 1 ) with insulating brickwork ( 1 a ) and optionally one or more further insulating layers arranged reformer ( R ) consists of a plurality of canned tubes ( 2 ), each at their lower ends in groups with collectors ( 3 ) and at their upper end with a collector ( 4 ).

The collector ( 3 ) rest on a transversely through the container ter extending vaulted ceiling ( 5 ) made of high-strength, high temperature-resistant building blocks ( 6 ) made of a ceramic material, for. B. Al ₂ O ₃ or SiO ₂ .

Between the lower end ( 4 a ) of the collector ( 4 ) and the top ( 5 a ) of the vaulted ceiling ( 5 ), a displacer hollow body ( 7 ) is arranged if this is necessary for flow reasons. A catalyst bed ( K ) is introduced between the can ( 2 ).

The process gas (PZ) entering the top of the container (1) flows through the catalyst bed (K) and the vault (5) passes through provided ducts (5 b) in a spanned by the vaulted ceiling gas collection space (9), and for this pulled down or to the side.

From the outside via one or more supply lines ( 10 ) hot heating gas (HG) , such as. B. helium from a Hochtem temperature reactor, into which the collector ( 3 ) is introduced and flows through the can ( 2 ) and is discharged via the collector ( 4 ).

The can are with their upper ends, which can be smaller in diameter than the can itself, so brought up to the collector ( 4 ) that the can ( 2 ) can expand upwards.

The vaulted ceiling ( 5 ) safely absorbs both the load on the can ( 2 ) and the weight of the catalytic converter ( K ).

The can ( 2 ) can be designed as separate ge led single tubes; however, the embodiments shown in Figs. 2 and 3 are preferred.

In the embodiment of Fig. 2 are connected by webs (2 a) to tube cylinders (RZ) with each other, the individual cracking tubes (2), which mutually are concentrically arranged, that is, when comparing the Figs. 2 and 1 are each three tubular cylinder with a Connected collector ( 3 ).

The upper ends of the tubes of the tubular cylinder (RZ) are connected in the manner shown in FIG. 2 via a curved section ( 2 b ) with the collector ( 4 ).

In the embodiment according to FIG. 3, a plurality of tube (2) by webs (2 a) to tube boards (RB) verbun together to the spirally wound and joined in a corresponding manner to the headers (3) and (4).

In the embodiment of Fig. 4, the catalyst (K) in the individual cracking tubes (2 ') is introduced. At their upper ends, the pipes ( 2 ') are connected to a ring collector ( 4 '), while at their lower ends they are connected to gas pipes ( 15 ) of reduced diameter. The tubes ( 2 ) and the gas guide tubes ( 15 ) can also be formed in one piece with one another. The gas guide tubes ( 15 ) pass through a layer ( 16 ) of gas distributing stones ( 17 ) on the top ( 5 a ) of the vaulted ceiling and the ceiling vault itself.

A gas guide column ( 18 ) extends centrally through the gas collection space ( 9 ) from the bottom of the gas collection space ( 9 ) to the distributor layer ( 16 ).

In this embodiment, the process gas (PZ) is distributed via the distributor ( 4 ') to the pipes ( 2 ') standing up on the distributor layer ( 16 ) and filled with catalyst ( K ). The gas enters the space ( 9 ) via the gas guide tubes ( 15 ) and is discharged from there. Heating gas (HG) is fed through a bottom opening ( 18 a ) to the guide column ( 18 ), flows upwards and enters the gas distribution layer ( 16 ). The gas distribution layer ( 16 ) ensures that the heating gas (HG) is evenly passed around the plurality of pipes ( 2 ') before it leaves the container at the upper end.

Here, too, the differential expansion of the pipes ( 2 ') is recorded at the upper end.

While there are internal collectors ( 4 ') in the embodiment according to FIG. 4, it is also possible to use external collectors, as will be described with reference to FIG. 5.

In the embodiment shown in Fig. 5, the upper ends of the tubes ( 2 ') via helical windings ( 19 ) with an external collector ( 4 '') are connected. In this arrangement, the heating gas (HG) , after it has flowed along the can ( 2 '), through the Helixwick lungs ( 19 ) still heat.

The operation of the distributor layer ( 16 ) will now be explained in more detail with reference to FIGS. 6 to 8.

In the embodiment shown in FIGS . 6 and 7, the distribution blocks ( 17 ) have a standing section ( 17 a ) and a head section ( 17 b ), which are connected to one another by a column section ( 17 c ). Stand section ( 17 a ) and head section ( 17 b ) have a hexagonal cross section, but in the case of the head section ( 17 b ) the corners are broken. The column section ( 17 c ) has a circular cross-section reduced in diameter.

The stand section ( 17 a ) is provided on its underside with a guide pin ( 17 d ). Each stone is provided with a central channel ( 17 e ) which is adapted to the diameter of the gas line pipes ( 15 ) and which is provided with a conical widening ( 17 f ) in the region of the head section ( 17 b ).

The catalyst ( K ) is held in the individual tube ( 2 ') by a perforated grid ( 2 c ).

On the top ( 5 a ) of the vaulted ceiling or in a separate layer of shaped stones ( 20 ) adapted recesses ( 21 ) are provided on the guide pin ( 17 d ). The shaped stones ( 20 ) and the stones of the vaulted ceiling are provided with bores ( 20 a ) and channels ( 5 b ) corresponding to the channel ( 17 e ).

As can be seen from FIGS. 6 and 7, when putting together a plurality of the shaped stones ( 17 ) between the column sections ( 17 c ), a grid-like gas distribution cavity ( 22 ) is formed, into which the heating gas (HG) from the gas guide column ( 18 ) can occur. From this gas distribution grid, the hot gas enters through the gas guide channels ( 23 ) formed by the broken edges of the head sections into the region of the catalyst. The distributor stones ( 17 ) on the one hand transfer the load of the canned tubes filled with the catalyst ( 2 ') into the vaulted ceiling ( 5 ) and on the other hand enable the gas to be distributed. The stones also represent the lower guide plate for the canned pipes. So that the gas emerging from the guide pipes ( 15 ) also flows into the collecting chamber ( 9 ), a seal must be made to the upper flow chamber. This seal is achieved on the one hand by the engagement of the pin ( 17 d ) in the stones ( 20 ) or in the vaulted ceiling ( 5 ) and on the other hand by lying on the can bottom ( 2 ) in the area of the conical expansion ( 17 f ) on the single manifold. In addition, the narrow gap of the guide tube in the stones ( 20 ) and / or the stones of the vault ( 5 ) constitutes a so-called gap seal. The effect of this gap seal could be further increased by the fact that in the area of the stones ( 20 ) or a labyrinth seal is provided for the stones of the vaulted ceiling ( 5 ).

Since the can ( 2 ) only lies on the distributor block ( 17 ), there is no force in the radial direction during operation. However, slight asymmetries can arise with regard to the radial forces, which can then be absorbed by slightly bending the gas guide tube ( 15 ) in the region of the conical extension ( 17 f ). The gas guide tube ( 15 ) of the individual can ( 2 ') can be easily pulled out of the molded block ( 17 ) and exchanged. The gas guide column ( 18 ) is preferably from a vault ( 5 ) with supporting outer wall ( 18 b ) from the ceramic stones used for the vault and an inner protective tube ( 18 c ) built on.

In the embodiment according to FIG. 8, the hexagonal corners of the head sections ( 17 ) are not broken, but corresponding recesses are provided on the head section either on opposite sides of two stones and form channels ( 23 ') (see FIG. 8 left triple) of blocks ( 17 )), or in each case on at least one side of a stone, a sufficiently large recess is seen before, which together with a non-recessed side form a gas duct ( 23 ''). (Compare the right triple of distributor blocks in FIG. 8.) With regard to geometry and design, reference is made in particular to FIGS. 6, 7 and 8. Other geometries for the distributor stones are conceivable, e.g. B. cuboid.

The embodiments according to FIGS. 9 and 10 differ from the previously described embodiments by the fact that the can ( 2 , 2 ') are not supported on a vaulted ceiling.

In the embodiment according to FIG. 9, the support tubes ( 2 ) are suspended via the collector ( 4 ) on a support structure ( 24 ), which in turn is supported on the container ( 1 ). At the lower end of the displacer ( 7 ) is connected to the bottom plate ( 25 ) provided with holes ( 25 a ) and ( 25 b ) for the gas or for the slotted tubes, through which the tubes ( 2 ) to a collector ( 3 ) are passed through. The base plate also carries the catalyst bed ( K ) poured in between the tubes ( 2 ). The product gas (PD) is drawn off under the base plate ( 25 ).

Heating gas (HG) is fed to the collector ( 3 ) from below. In this embodiment, the can ( 2 ) are suspended and carry the weight of the catalyst bed ( K ) together with the central displacer ( 7 ). The expansion compensation is essentially carried out by pushing the lower collector. In this embodiment, fins wall cylinders and spirally wound fin walls can also be used in addition to the individual tubes. Of course, a plurality of collectors can be used instead of a collector ( 3 ), for. B. identical in Fig. 1st

In the embodiment shown in Fig. 10, the catalyst is in the can, which are individually hanging on a support plate ( 26 ) attached. The lower ends of the can ( 2 ') are connected to a collector ( 3 ), from the lower end of which the product gas (PD) is drawn off. As shown in FIG. 10, left half ersicht Lich, the individual canned tubes ( 2 ) concentric cladding tubes ( 27 ) can be assigned at a distance, which depend from a support plate ( 28 ) arranged below the support plate ( 26 ). The right half shows the arrangement without a cladding tube.

In this embodiment, the expansion is compensated for by pushing the lower collector ( 3 ): the convective heating can take place with or without a cladding tube.

Finally, Fig. 11 shows that with sufficient heat content of the heating gas, it can not only be useful to proceed as in Fig. 5, but to carry out a heat exchange decoupled from the direct circuit. For this purpose, a heat exchanger ( 29 ), e.g. B. helical heat exchanger, with inlet header ( 29 a ), heating surfaces ( 29 b ), outlet header ( 29 c ) and displacement body ( 29 d ), which is acted upon with a heat transfer medium (WM) .

In Fig. 1 the container ( 1 ) is usually shown in one piece to simplify the illustration. However, it can consist of parts connected by means of flanges. Furthermore, manholes and any existing openings for filling and / or removing catalyst material are not shown for the same reasons. Furthermore, one or more guiding grids can be provided along the pipes, such as. B. Grid ( 30 ) in Fig. 4th

Claims (12)

1. Reformer for the catalytic cracking of gaseous hydrocarbons, in particular with steam to a product gas with a pressure vessel, a plurality of gap tubes arranged in parallel in the vessel and a catalyst, whereby through the tube walls convective heat from a hot heating gas to the the process flowing through the catalyst is gas transferable, characterized in that the heating gas (HG) is passed through the gap tubes ( 2 ') and the catalyst ( K ) is introduced as a bed in the pressure vessel ( 1 ) between the gap tubes. 2. Reformer according to claim 1, characterized in that the can ( 2 ') and the catalyst ( K ) are supported hanging in the container ( 1 ). 3. Reformer for the catalytic cracking of gaseous hydrocarbons, in particular with steam to a product gas with a pressure vessel, a plurality of gap tubes arranged in parallel in the vessel and a catalyst, whereby through the tube walls convective heat from a hot heating gas to the the process flowing through the catalyst is gas transferable, characterized in that the tubes ( 2 ; 2 ') standing on a built of a ceramic material and a gas collecting space ( 9 ) for the product gas (PD) delimiting and provided with gas passages ( 5 b ) Ceiling vault ( 5 ) is supported together with the catalyst ( K ). 4. Reformer according to one of claims 1 to 3, characterized in that the catalyst ( K ) in a manner known per se in the gap tubes ( 2 ) is arranged, and that the can tubes are flowed around by the heating gas. 5. Reformer according to one of claims 1 to 4, characterized in that the gap tubes ( 2 ; 2 ') are formed in a conventional manner as separate individual tubes or as concentric to the container axis fin walls (RZ) or as spirally wound and optionally fins (RB) welded together are formed. 6. Reformer according to one of claims 1 to 5, characterized in that the standing canned tubes ( 2 ) via collectors ( 3 ) are supported on the ceiling arch ( 5 ). 7. Reformer according to one of claims 1 to 6, characterized in that the standing canned tubes ( 2 ) on a distributor layer ( 16 ) of distributor blocks ( 17 ) on the vaulted ceiling ( 5 ) are supported. 8. A reformer according to claim 7, characterized in that the distributor blocks ( 17 ) are formed from such that they are arranged in a side-by-side arrangement with a flat and towards the lower side of the layer essentially gas-tight and towards the top thereof with gas distribution openings ( 23 ; 23 '; 23 '') provide the gas distribution network, and that on the United sub-layer ( 16 ) standing can ( 2 ; 2 ') with gas pipes ( 15 ) reach through the manifolds ( 17 ). 9. Reformer according to one of claims 1 to 8, characterized in that filled with catalyst ( K ) and flowed through by the process gas (PZ) canned tubes ( 2 ') are each surrounded by a concentric cladding tube ( 27 ) at a relatively close distance that the heating gas (HG) flows, while dead spaces that are not flowed through are formed outside the cladding tubes in the area of the reformer. 10. Reformer according to one of claims 1 to 9, characterized in that Einrich lines ( 19 ; 29 ) for further heat dissipation from the heating gas (HG) are provided after the convective heating of the catalyst ( K ). 11. Reformer according to claim 10, characterized in that the devices for further heat dissipation of separate tube windings ( 19 ) are formed at one end of the can. 12. Reformer according to claim 10, characterized in that in the pressure vessel ( 1 ) the reformer ( R ) in the outflow of the heating gas (HG) a ge and in another heat transfer circuit switched heat exchanger ( 29 ) is assigned.