EP1049534A1

EP1049534A1 - Plate catalytic reactor

Info

Publication number: EP1049534A1
Application number: EP99900512A
Authority: EP
Inventors: William Levy; Dominique Sabin; Christine Girod
Original assignee: Packinox SA
Current assignee: Alfa Laval Packinox SAS
Priority date: 1998-01-22
Filing date: 1999-01-11
Publication date: 2000-11-08
Also published as: WO1999037394A1; FR2773726B1; FR2773726A1

Abstract

The invention relates to a plate catalytic reactor of the type comprising a sealed enclosed space (1) and a plate bundle (2) arranged inside said sealed enclosed space. The plates of the plate bundle (2) delimit a first series of channels which form a circuit in which a main fluid A is able to circulate, a second series of channels which form a circuit in which a coolant B is able to circulate in a direction which is perpendicular to the direction of circulation of the main fluid A, and a third series of channels which form a circuit in which a coolant C is able to circulate in a direction which is perpendicular to the direction of circulation of the main fluid A and opposite to the direction of circulation of coolant B flowing in the second series of channels. Said catalytic converter is used for producing, for example, phthalique anhydride.

Description

99/37394

"Catalytic plate reactor"

The present invention relates to a catalytic plate reactor intended in particular for the production of phthalic anhydride.

It is known that for the production of certain fluids, such as phthalic anhydride, first of all, air and ortho-xylene are mixed to produce a main fluid, then this fluid is circulated main in a catalytic reactor in the presence of a catalyst to carry out the desired reaction. In view of the very strong isothermal reaction which occurs during the passage of the main fluid through the catalyst, this reaction can only take place in reactors cooled by an auxiliary fluid which is most often constituted by a mixture of molten salts. Up to now, for the production of this kind of fluid, catalytic reactors have been used formed by a sealed enclosure inside which are arranged parallel tubes filled with catalyst.

The main fluid circulates in these tubes inside which the reaction takes place and the cooling fluid circulates outside of said tubes, between them and the internal wall of the enclosure.

The main drawback of these tubular reactors lies in their dimensions because, for large units, the number of tubes quickly becomes very large and the diameter of the device excessive.

A catalytic plate reactor is also known which comprises a bundle of plates delimiting a first circuit for circulation of a main fluid formed by at least two components and a second circuit for circulation of a secondary cooling fluid, the two fluids circulating against the current in the plate bundle.

The means of entry of each fluid into the corresponding circuits are formed by a multitude of small collectors. The main fluid inlet manifolds are filled with catalyst and comprise at least one injection manifold for each component of said main fluid.

However, this arrangement is complex and the cost of such a catalytic reactor is high given the number of manifolds and injection manifolds.

The invention aims to avoid these drawbacks by proposing a catalytic plate reactor having a low construction cost and a weight saving, while allowing a significant reduction in pressure losses and a better coefficient of heat exchange between the fluids.

The subject of the invention is therefore a catalytic plate reactor, of the type comprising a sealed enclosure of elongated shape and a bundle of plates arranged inside said sealed enclosure by providing with the latter a free space formed by a stack. of metal plates provided with corrugations, characterized in that the plates delimit between them: - a first series of channels forming a circulation circuit of a main fluid formed of at least two components, said channels communicating with means of inlet and outlet of the main fluid and containing a catalyst, - a second series of channels forming a circuit for circulation of a cooling fluid in a direction perpendicular to the direction of circulation of the main fluid and communicating with intake means and discharge of the coolant, - and a third series of channels forming a circuit for circulating a coolant ment in a direction perpendicular to the direction of circulation of the main fluid and opposite to the direction of circulation of the cooling fluid in the second series of channels, said channels of the third series communicating with the inlet and outlet means coolant and each channel of the first series being arranged 99/37394

between the channels of the second and third series respectively.

According to other characteristics of the invention: the means for admitting the main fluid are formed by a conduit opening into the free space formed between the sealed enclosure and the bundle of plates and communicating with the inlet zones of the channels of the first series, the means for discharging the main fluid are formed by a manifold disposed inside the sealed enclosure and covering the outlet zones of the channels of the first series and by an outlet conduit connected to said manifold,

the means for admitting the coolant into the second series of channels are formed by a manifold disposed inside the sealed enclosure and covering the inlet zones of these channels and by an inlet duct connected to said collector and the means for discharging this cooling fluid are formed by a collector disposed inside the sealed enclosure and covering the outlet zones of said channels and by an outlet duct connected to said collector,

the means for admitting the cooling fluid into the third series of channels are formed by a manifold disposed inside the sealed enclosure and covering the inlet zones of these channels and by an inlet duct connected to said collector and the means for discharging this cooling fluid are formed by a collector arranged inside the sealed enclosure and covering the outlet zones of said channels and by an outlet duct connected to said collector,

the channels of the first series comprise a central part filled with catalyst and connected to means for filling said central part and to means for discharging spent catalyst,

the catalyst filling means are formed by a manifold disposed at a first end of the central part of said channels of the first series and by an inlet conduit connected to said manifold and the discharge means are formed by a manifold disposed at a second end of said central portion opposite the first end and by an outlet conduit connected to said collector,

the catalyst is maintained in the channels of the first series by grids allowing the circulation of the main fluid in said catalyst, the sealed enclosure is provided with at least one rupture disc calibrated at a determined pressure,

- the main fluid consists of a mixture of air and ortho-xylene to obtain phthalic anhydride after passage through the catalyst, - the cooling fluid consists of a mixture of molten salts.

The invention will be better understood on reading the description which follows, given by way of example and made with reference to the appended drawings, in which: - FIG. 1 is a schematic view partially in longitudinal section of a catalytic reactor according to the invention,

- Fig. 2 is a partial perspective view of one end of the bundle of plates of the catalytic reactor,

- Fig.3 is a partial perspective view of the other end of the plate bundle of the catalytic reactor,

- Fig. 4 is a sectional view along line 4-4 of Fig. 2.

In Fig. 1, there is shown a catalytic plate reactor intended in particular for the production of phthalic anhydride by passing a mixture of air and ortho-xylene in given proportions over a catalyst. For this, the catalytic reactor comprises a sealed enclosure 1 of elongated shape and of circular section, for example. O 99/37394

This sealed enclosure 1 is preferably arranged vertically.

Inside the sealed enclosure 1 is placed a bundle of plates designated as a whole by the reference 2 and of generally parallelepipedal shape.

This bundle of plates 2 leaves the enclosure 1 free space 3.

As shown in Figs. 2 and 3, the bundle of plates 2 is formed by a stack of plates 4 parallel to each other and delimiting a multitude of channels 10 which extend longitudinally from one end to the other of the bundle of plates 2.

Conventionally, the plates 4, for example made of stainless steel, are held together by suitable means and have edges with a smooth surface and a central part provided with corrugations, not shown, by which they are in contact with one another. and by which they delimit the channels 10.

In the embodiment shown in Figs. 2 and 3, the plates 4 delimit between them a first series of channels 10A forming a circulation circuit for a main fluid A consisting of at least two components which are for example air and ortho-xylene.

The channels 10A are distributed over one channel 10 out of two in the bundle of plates 2 and the fluid A circulates in these channels 10A transversely with respect to the longitudinal axis of said bundle of plates 2.

To this end and as shown in FIG. 2, a side face of the bundle of plates 2 comprises inlet zones 12A of the main fluid A while the openings of one channel out of two are closed by the closure members 11 formed for example by tongues extending over the entire length of said lateral face of the bundle of plates 2. Likewise, the other lateral face of the bundle of plates 2 shown in FIG. 3 comprises outlet zones 13A of the main fluid A after passage through the channels 10A while one channel out of two is closed by closure members 11 formed by tongues extending over the entire length of said lateral face of the bundle of plates 2. The plates 4 also delimit a second series of channels 10B forming a circuit for circulating a cooling fluid B in a direction perpendicular to the direction of circulation of the fluid A.

The channels 10B are distributed over one channel 10 out of three in the bundle of plates 2 and one of the end faces of this bundle of plates 2, shown in FIG. 2, comprises inlet zones 12B of the cooling fluid B, while the other lateral face of the bundle of plates 2, shown in FIG. 3, comprises outlet zones 13B of this cooling fluid.

The cooling fluid consists, for example, of a mixture of molten salts.

The plates 4 also delimit between them a third series of channels 10C forming a circuit for circulating a cooling fluid C in a direction perpendicular to the direction of circulation of the main fluid A in the channels 10A and opposite to the direction of circulation of the coolant B in the channels 10B. The channels 10C are distributed over one channel 10 out of three in the bundle of plates 2 and one of the end faces of this bundle of plates 2, shown in FIG. 3, has inlet zones 12C for the cooling C, while the other end face of the plate bundle 2, represented in FIG. 2, has outlet zones

13C of this cooling fluid C.

The cooling fluid C also consists of a mixture of molten salts.

Thanks to this arrangement, each channel 10A of the first series for the circulation of the main fluid A is disposed between a channel 10B of the second series and a channel 10C of the third series for the circulation of fluids. 99/37394

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cooling which allows optimal cooling of the main fluid A.

Thus, on one of the end faces of the bundle of plates 2 (FIG. 2) are formed inlet zones 12B of the cooling fluid B and outlet zones 13C of the cooling fluid C and on the other of these end faces of the plate bundle 2 (FIG. 3) are formed from the outlet zones 13B of the cooling fluid B and from the inlet zones 12C of the cooling fluid C. On the end faces of the plate bundle

2, the ends of the channels 10 located between the inlet areas 12B and the outlet areas 13C or the inlet areas 12C and the outlet areas 13B of each cooling fluid B and C are closed by shutter members - tion 11.

The closure members 11 of the channels 10 of the lateral faces and of the end faces of the bundle of plates 2 are formed, for example by tongues welded to the edges of the corresponding plates 4 or by folded edges of the plates 4 and the ends are welded together.

The catalytic reactor also includes means for admitting and discharging the main fluid A into the channels 10A and respectively means for admitting and discharging the cooling fluid B in the channels 10B and means for admitting and d evacuation of the cooling fluid C in the channels 10C.

As shown in FIG. 1, the means for admitting the main fluid A into the inlet zones 12A of the channels 10A are formed by a conduit 20 opening into the free space 3 formed between the sealed enclosure 1 and the bundle of plates 2 and communicating with the input zones 12A of the first series channels 10A.

The main fluid A spreads inside the sealed enclosure 1 and the overpressure thus generated keeps the bundle of plates 2 in compression. O 99/37394

The means for discharging the main fluid A after passing through the channels 10A are formed by a manifold 21 disposed inside the seal 1 and covering the outlet zones 13A from the channels 10A of the first series and by a conduit outlet 22 connected to said manifold.

The means for admitting the coolant B into the second series of channels 10B of the plate bundle 2 are formed by a manifold 23 disposed inside the sealed enclosure 1 covering the inlet zones 12B of these channels 10B and by an inlet conduit 24 connected to the manifold 23.

The means for discharging this cooling fluid B are formed by a manifold 25 disposed inside the sealed enclosure 1 and covering the outlet zones 13B of the channels 10B and by an outlet conduit 26 connected to this manifold 25 .

The means for admitting the coolant C into the third series of channels 10C of the bundle of plates 2 are formed by a manifold 27 disposed inside the sealed enclosure 1 and covering the inlet zones 12C of these channels 10C and by an inlet conduit 28 connected to said collector 27.

Finally, the means for discharging the cooling fluid C from the channels 10C are formed by a manifold 29 disposed inside the sealed enclosure 1 and covering the outlet zones 13C from the channels 10C and by an outlet conduit 30 connected to this collector 29.

In the exemplary embodiment shown in FIG. 1, the manifold 23 for admitting the coolant B into the channels 10B is situated opposite the manifold 27 for admitting the coolant C into the channels 10C and the manifold 25 for discharging the fluid B from the channels 10B is located opposite the manifold 29 for discharging the cooling fluid C from the channels 10C. On the other hand, the channels 10A for circulation of the main fluid A contain particles 35 of catalyst so as to provoke the desired reaction during the passage. 99/37394

sage of the main fluid A composed of air and ortho-oxylene to collect via the manifold 21 and the outlet conduit 22 of the phthalic anhydride.

Preferably and as shown in FIG. 4, the catalyst particles 35 are arranged in the central part of the channels 10A and this central part is connected to filling means and to means for discharging the spent catalyst particles.

The catalyst particles 35 are held on each side of the central part of the channels 10A by a grid 36 which extends over the entire length of the plate bundle 2. The grids 36 have meshes sufficiently fine to hold these catalyst particles 35 , while allowing the passage through these particles 35 of the main fluid A.

As shown in FIG. 1, the means for filling catalyst particles 35 in the channels 10A are formed by a manifold 31 arranged on an end face of the bundle of plates 2 and preferably at the top of the reactor. catalytic and by a conduit 32 connected to said manifold 31.

The means for removing the catalyst particles 35 are formed by a manifold 33 disposed on the other end face of the bundle of plates 2 and preferably at the bottom of the catalytic reactor and by an outlet conduit 34 connected audit collector 33.

The production of phthalic anhydride presents risks of explosion at the level of the entry of the main fluid composed of air and ortho-xylene and the sealed enclosure is, therefore, provided with at least one disc of rupture 37 dimensioned amply according to the explosion conditions in order to contain the increase in pressure within given limits and for example less than 10 bars inside the sealed enclosure 1. The main fluid A composed of a mixture air and ortho-xylene is introduced through the inlet conduit 20 inside the sealed enclosure 1 and enters the chambers 10 channels 10A through the inlet zones 12A formed on the lateral face of the bundle of plates 2.

This main fluid A therefore circulates inside the channels 10A, then passes through the catalyst particles 35 so as to obtain the desired reaction and the phthalic anhydride thus produced leaves the channels 10A through the outlet zones 13A formed on the other side face of the bundle of plates 2 and leaves the catalytic reactor via the manifold 21 and the outlet duct 22. Simultaneously with the circulation of the main fluid A, the cooling fluid B composed of a mixture of molten salts is injected into all of the channels 10B via the inlet conduit 24, the manifold 23 and the inlet zones 12B and spreads over the entire surface of these channels 10B, then leaves the catalytic reactor via the outlet zones 13B, the manifold 25 and the outlet duct 26.

Similarly, the cooling fluid C composed of a mixture of molten salts is injected into the channels 10C of the plate bundle 2 through the inlet duct 28, the manifold 27 and the inlet areas 12C, then spreads over the entire surface of these channels 10C and leaves the catalytic reactor via the outlet zones 13C, the manifold 29 and the outlet conduit 30.

Thus, the main fluid A is cooled during its passage through the bundle of plates 2 by the coolants B and C which circulate on either side of the channels 10A intended for the circulation of the main fluid A.

After a certain period of use, the particles 35 of spent catalyst are evacuated by gravity from the channels 10A by the collector 33 and the outlet conduit and new particles 35 of catalyst are introduced into these channels 10A by the collector 31 and the inlet duct 32. Preferably, each end face of the bundle of plates 2 has a trapezoidal shape in order to allow the center to install the collectors 31 and 33 O 99/37394

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flow of the catalyst particles and on the sides the installation of the collectors 23 and 27 for the entry of the coolants and the collectors 25 and 29 for the exit of the coolants. The circulation of the main fluid A and of the cross-flow coolants B and C and the circulation of the fluids B and C against the current with respect to each other makes it possible to obtain a substantial reduction in pressure losses and a better coefficient of heat exchange between the fluids.

Finally, this arrangement has the advantage of reducing the construction cost and obtaining a weight saving.

Claims

12 CLAIMS

1. Catalytic plate reactor, of the type comprising a sealed enclosure (1) of elongated shape and a bundle of plates (2) disposed inside said sealed enclosure (1) by providing a free space therewith. (3) and formed by a stack of metal plates (4) provided with corrugations, characterized in that the plates (4) delimit between them:

a first series of channels (10A) forming a circulation circuit for a main fluid A formed from at least two components, said channels (10A) communicating with inlet (20) and outlet (21, 22) of the main fluid A and containing a catalyst (35),

- A second series of channels (10B) forming a circuit for circulation of a cooling fluid B in a direction perpendicular to the direction of circulation of the main fluid A and communicating with intake means (23,24) and evacuation (25, 26) of the coolant B, - a third series of channels (10C) forming a circuit for circulating a coolant C in a direction perpendicular to the direction of circulation of the main fluid A and opposite to the direction of circulation of the coolant B in the second series of channels (10B), said channels (10C) of the third series communicating with inlet (27, 28) and outlet (29, 30) means ) of the coolant C and each channel of the first series (10A) being arranged between the channels (10B, 10C) of the second and of the third series, respectively.

2. Catalytic reactor according to claim 1, characterized in that the means for admitting the main fluid A are formed by a conduit (20) opening into the free space (3) formed between the sealed enclosure (1) and the bundle of plates (2) and communicating with the entry zones (12A) of the channels (10A) of the first series. 13

3. Catalytic reactor according to claim 1, characterized in that the means for discharging the main fluid A are formed by a manifold (21) disposed inside the sealed enclosure (1) and covering the outlet zones ( 13A) of the channels (10A) of the first series and by an outlet conduit (22) connected to said manifold (21).

4. Catalytic reactor according to claim (1), characterized in that the means for admitting the coolant (B) into the second series of channels (10B) are formed by a manifold (23) disposed inside the sealed enclosure (1) and covering the inlet zones (12B) of these channels (10B) and by an inlet duct (24) connected to said reactor and the means for discharging this cooling fluid B are formed by a manifold (25) disposed inside the sealed enclosure (1) and covering the outlet zones (13B) of said channels (10B) and by an outlet duct (26) connected to said manifold (25).

5. Catalytic reactor according to claim 1, characterized in that the means for admitting the cooling fluid C into the third series of channels (10C) are formed by a manifold (27) disposed inside the sealed enclosure (1) and covering the inlet zones (12C) of these channels (10C) and by an inlet duct (28) connected to said manifold (27) and the means for discharging this cooling fluid C are formed by a collector

(29) disposed inside the sealed enclosure (1) and covering the outlet zones (13C) of said channels (10C) and by an outlet conduit (30) connected to said manifold (29).

6. Catalytic reactor according to claim 1, characterized in that the channels (10A) of the first series have a central part filled with catalyst (35) and connected to filling means (31, 32) of said central part and to means for evacuating (33, 34) the spent catalyst (35).

7. Catalytic reactor according to claim

6, characterized in that the catalyst filling means (35) are formed by a manifold (31) disposed at a 14

first end of the central part of said channels (10A) of the first series and by an inlet conduit (32) connected to said (31) and the discharge means are formed by a manifold (33) disposed at a second end of the central part opposite the first end and by an outlet conduit (34) connected to said manifold (33).

8. Catalytic reactor according to claim 1 or 6, characterized in that the catalyst (35) is held in the channels (10A) of the first series by grids (36) allowing the circulation of the main fluid A in said catalyst (35 ).

9. Catalytic reactor according to claim 1, characterized in that the enclosure (1) and provided with at least one rupture disc (37) calibrated at a determined pressure.

10. Catalytic reactor according to any one of the preceding claims, characterized in that the main fluid A consists of a mixture of air and ortho-oxylene to obtain after passage through the catalyst (35) d phthalic anhydride.

11. Catalytic reactor according to one of claims 8 to 9, characterized in that the cooling fluid B or C consists of a mixture of molten salts.