REACTOR COMPRISING A VERTICALLY MOVABLE GAS LOCK

Abstract

A reactor for catalytic conversion of gas mixtures may include a catalyst bed. An upper side of the catalyst bed may include a gas lock that is movable in a vertical direction. The gas lock may be lowered when the catalyst bed contracts. In some examples, the gas lock prevents a gas mixture from flowing out of the catalyst bed via the upper side of the catalyst bed.

Claims

1.-17. (canceled)

18. A reactor for catalytic conversion of a gas mixture, the reactor comprising: a vessel; a catalyst bed disposed between a first lateral delimitation and a second lateral delimitation of the vessel, wherein the first lateral delimitation comprises a plurality of lateral gas inlets through which the gas mixture flows into the catalyst bed to at least partly react, wherein the second lateral delimitation comprises a plurality of lateral gas outlets through which the gas mixture flows out of the catalyst bed; a gas lock that is movable in a vertical direction and is disposed along only a first part of an upper side of the catalyst bed; and an upper gas inlet disposed along a second part of the upper side of the catalyst bed, wherein the second part of the upper side does not overlap with the first part of the upper side, wherein the gas mixture flows from above the upper gas inlet into the catalyst bed.

19. The reactor of claim 18 wherein the gas lock is lowered in the vertical direction by gravitational force when the catalyst bed contracts.

20. The reactor of claim 18 wherein an outer periphery of the gas lock lies flush against the second lateral delimitation.

21. The reactor of claim 18 wherein the gas lock comprises a plurality of segments that overlap horizontally.

22. The reactor of claim 21 wherein the plurality of segments are connected to one another movably such that the horizontal overlap of the plurality of segments is retained when the gas lock moves vertically.

23. The reactor of claim 18 wherein at least one of the first lateral delimitation or the second lateral delimitation comprises a perforated plate.

24. The reactor of claim 18 wherein the first lateral delimitation forms an outer cylinder and the second lateral delimitation forms an inner cylinder, wherein the inner cylinder is positioned concentrically within the outer cylinder and the outer cylinder is positioned concentrically within the vessel, wherein the catalyst bed is positioned between an inner side of a wall of the outer cylinder and an outer side of a wall of the inner cylinder, wherein the vessel has a substantially circular cross-section, wherein an annular gap exists between an inner side of a wall of the vessel and an outer side of the wall of the outer cylinder through which the gas mixture flows before entering the plurality of lateral gas inlets in the outer cylinder.

25. The reactor of claim 24 wherein the plurality of lateral gas inlets of the first lateral delimitation are disposed in the wall of the outer cylinder so that the gas mixture flows from the annular gap into the catalyst bed radially from a side via the plurality of lateral gas inlets through the wall of the outer cylinder, wherein the plurality of lateral gas inlets of the second lateral delimitation are disposed in the wall of the inner cylinder so that the gas mixture flows radially out of the catalyst bed through the plurality of lateral gas inlets in the wall of the inner cylinder and into an inner cavity formed by the inner cylinder and via which the gas mixture is dischargeable.

26. The reactor of claim 24 wherein the plurality of gas inlets in or along the wall of the outer cylinder differ in at least one of a number, a size, or a position than the plurality of gas inlets in or along the wall of the inner cylinder.

27. The reactor of claim 24 wherein the gas lock is configured as an annular disk with an inner periphery that lies flush against the outer side of the wall of the inner cylinder.

28. The reactor of claim 27 wherein both an outer periphery of the annular disk and the inner side of the wall of the outer cylinder have a substantially circular shape, with the outer periphery of the annular disk being smaller than the inner side of the wall of the outer cylinder, wherein a second annular gap that forms the upper gas inlet exists between the inner side of the wall of the outer cylinder and the outer periphery of the annular disk.

29. The reactor of claim 28 wherein the inner periphery of the annular disk is substantially circular and has a radius R.sub.1, wherein the outer side of the wall of the inner cylinder is substantially circular and has a radius R.sub.2, wherein a surface area F.sub.1 of the annular disk in a main plan of extent follows F.sub.1=(R.sub.2.sup.2R.sub.1.sup.2), wherein the inner side of the wall of the outer cylinder is substantially circular and has a radius R.sub.3, wherein the surface area F.sub.2 of the second annular gap follows F.sub.2=(R.sub.3.sup.2R.sub.2.sup.2) and F.sub.1 is greater than or equal to F.sub.2.

30. The reactor of claim 27 wherein in an upper region of the inner cylinder against which the inner periphery of the annular disk lies, the inner cylinder at least one of does not include a gas outlet, or includes gas outlets that are closed in a flush manner by a concentrically arranged closure lying on an inside or an outside.

31. The reactor of claim 30 wherein an upper region of the outer cylinder comprises at least some of the plurality of lateral gas inlets, which is arranged substantially parallel to the upper region of the inner cylinder.

32. A method for catalytic ammonia synthesis, a gas mixture substantially comprising nitrogen and hydrogen being made to react under increased pressure and at increased temperature in a reactor as recited in claim 18.

33. An ammonia converter comprising at least two reactors arranged one above another in a common pressure vessel, each of the at least two reactors comprising: a vessel; a catalyst bed disposed between a first lateral delimitation and a second lateral delimitation of the vessel, wherein the first lateral delimitation comprises a plurality of lateral gas inlets through which the gas mixture flows into the catalyst bed to at least partly react, wherein the second lateral delimitation comprises a plurality of lateral gas outlets through which the gas mixture flows out of the catalyst bed; a gas lock that is movable in a vertical direction and is disposed along only a first part of an upper side of the catalyst bed; and an upper gas inlet disposed along a second part of the upper side of the catalyst bed, wherein the second part of the upper side does not overlap with the first part of the upper side, wherein the gas mixture flows from above the upper gas inlet into the catalyst bed, wherein the first lateral delimitation forms an outer cylinder and the second lateral delimitation forms an inner cylinder, wherein the inner cylinder is positioned concentrically within the outer cylinder and the outer cylinder is positioned concentrically within the vessel, wherein the catalyst bed is positioned between an inner side of a wall of the outer cylinder and an outer side of a wall of the inner cylinder, wherein the vessel has a substantially circular cross-section, wherein an annular gap exists between an inner side of a wall of the vessel and an outer side of the wall of the outer cylinder through which the gas mixture flows before entering the plurality of lateral gas inlets in the outer cylinder.

34. A method for catalytic ammonia synthesis, a gas mixture substantially comprising nitrogen and hydrogen being made to react under increased pressure and at increased temperature in an ammonia converter as recited in claim 33.

Description

EXAMPLE

[0054] The advantages of the reactor according to the invention or of the ammonia converter according to the invention were verified by simulation calculations. The simulation software FLUENT was used for this. Apart from the flow equations, these calculations also take into account the reaction kinetics and the heat transfer, so that a quantitative assessment of the structural modification is possible.

[0055] A conventional ammonia converter with a capacity of 1200 t NH.sub.3/d was used for purposes of comparison. This reference converter comprised three reactors lying one above the other with in each case a catalyst bed, the upper reactor (reactor 1) and the middle reactor (reactor 2) being formed with a heat exchanger and all three reactors comprising in the cavity that was formed by the inner cylinder a further cylinder as a deflecting tube (for the deflecting tube, cf. FIGS. 5 and 9, reference numeral (14)). Separate FLUENT calculations were not carried out for reactor 1 and reactor 2. The amount of gas at the inlet into the catalyst bed of reactor 1 was 596149 Nm.sup.3/h. The inlet and outlet conditions for the three catalyst beds of this reference converter are summarized in the following table:

TABLE-US-00001 Inlet Outlet T % by vol. T % by vol. [ C.] NH.sub.3 [ C.] NH.sub.3 1st catalyst bed 400.0 3.01 506.5 9.73 2nd catalyst bed 438.2 9.73 479.2 13.31 3rd catalyst bed 424.3 13.31 457.2 15.83

[0056] The ammonia converter according to the invention was structurally modified by individual measures (cf. FIG. 9).

[0057] Structural modifications only for reactor 3 (also in the case of the reference converter without a heat exchanger): [0058] a) omission of the deflecting tube, filling the volume that has become free with catalyst, unhindered outflow; [0059] b) as under a), in addition differently perforated plates at the inlet and outlet of the catalyst bed.

[0060] Structural modifications for all three reactors: [0061] c) providing loose, floating segments of the circle as a gas lock above the upper side of the catalyst beds, together with partial opening of the flow access to the catalyst refill volume; making flow through the catalyst bed from above possible.

[0062] For all of the structural modifications, the pressure loss, NH.sub.3 concentration (% by vol. NH.sub.3) at the outlet of the catalyst bed and the resultant additional annual production of NH.sub.3 were calculated. The results are summarized in the following table:

[0063] Results of the structural modifications only to reactor 3:

TABLE-US-00002 Additional Outlet production T Vol.-% P of NH.sub.3 Geometry [ C.] NH.sub.3 [bar] [t/a] 3rd catalyst bed: reference 457.16 15.83 0.40 0 3rd catalyst bed: without 458.05 15.90 0.60 2354 deflecting tube, instead more catalyst, gas lock 3rd catalyst bed: without 458.15 15.91 0.61 2585 deflecting tube, instead more catalyst, differently perforated plates at the inlet and outlet of the bed, gas lock 3rd catalyst bed: without 458.22 15.92 0.55 2780 deflecting tube, instead more catalyst, gas lock, partial opening for the flow from above

[0064] Results of the structural modifications only to reactor 1:

TABLE-US-00003 Additional Outlet production T % by vol. of NH.sub.3 Geometry [ C.] NH.sub.3 [t/a] 1st catalyst bed: reference 506.50 9.73 0 1st catalyst bed: gas lock, partial 508.14 9.84 3672 opening for the flow from above

[0065] Results of the structural modifications to all three reactors:

TABLE-US-00004 Additional Outlet production T % by vol. of NH.sub.3 Geometry [ C.] NH.sub.3 [t/a] 1st-3rd catalyst bed: reference 457.16 15.83 0 3rd catalyst bed: without deflecting 458.31 15.93 4182 tube, instead more catalyst; also differently perforated plates at the inlet and outlet of the catalyst bed; 1st-3rd catalyst bed: gas lock, partial opening for the flow from above

[0066] As the results of the simulation calculations that are summarized above confirm, the annual production of NH3 can be increased considerably by the structural improvements according to the invention.