Multiple-bed catalytic reactor comprising sandwich tube sheet

Abstract

The present invention relates to a catalytic heat exchange reactor for carrying out endothermic or exothermic catalytic reactions with improved fluid sealing for high temperature reactions by means of sliding support of the heat transfer tubes in the reactor and heat exchange fluid cooling of a sandwich tube sheet.

Description

[0001] Multiple-bed catalytic reactor comprising sandwich tube sheet

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a heat exchange reactor for carrying out endothermic or exothermic catalytic reactions. In particular, the present invention relates to a heat exchange reactor with at least tube supporting sandwich tube sheet with improved fluid sealing for high temperature reactions. The heat exchange reactor may be part of a large apparatus, such as a production apparatus.

[0004] Catalytic reactors for carrying out endothermic or exothermic reactions are well known in the art, particular examples being reactors for the endothermic steam reforming of hydrocarbons and reactors for the exothermic methanol synthesis reactions (not limiting the scope of the invention to these reactions). The reactions are typically carried out in tubes loaded with a suitable solid catalyst through which a process gas stream comprising the reactants is passed at elevated pressure. A plurality of tubes is arranged vertically or horizontally in the reactor. The tubes run in parallel along the major axis of the catalytic reactor, while a heat-exchanging medium outside the tubes heats or cools the tubes. The solid catalyst inside the tubes provides a catalyst bed in which the required chemical reactions take place. The catalyst can be provided as solid particles or as a coated structure, for example as a thin layer fixed on the inner wall of the tubes in steam reforming reactors.

[0005] In another reactor configuration comprising a plurality of tubes the solid catalyst particles may be disposed outside said tubes, hereinafter also referred to as heat transfer tubes, whilst the heat exchanging medium passes inside. The solid catalyst outside the heat transfer tubes provides the catalyst bed in which the required chemical reactions take place.

[0006] Further types of heat transfer tubes and heat exchange reactors are known in the art. In the following, the invention is explained with reference to heat exchange reactors and heat transfer tubes with the catalysts arranged inside the tubes and where the tubes and reactor is arranged substantially vertically. However, the scope of the invention is not limited to this type of tubes and reactors. The terms “catalytic reactor”, “heat exchange reactor” and “reactor” are used interchangeably. By “catalyst bed” is meant the volume of solid catalyst forming said bed and which is inside the heat transfer tubes. The terms “heat transfer tubes” and “tubes” are used interchangeably and cover the tubes which are in contact with catalyst as well as a heat exchanging medium for the purpose of carrying out catalytic reactions.

[0007] The HTER-s is a tubular heat exchange reformer. It is a catalytic reactor and more specifically a heat exchanger with catalyst inside a plurality of tubes arranged within the heat exchange reactor. It has two separate flows; a process gas which flows inside the tubes and an effluent gas which flows on the shell side of the tubes (outside the tubes). The tubes are mounted between two tube sheets. As the tubes elongate individually during operation, a mechanism for taking up the elongation in at least one of the tube sheets must be present to avoid bending of the tubes an to avoid critical stress in the material and structure.

[0008] Previous concepts comprised tubes welded to the bottom tube sheet where elongation was taken up by a stuffing box for each tube located at the upper tube sheet. The stuffing box supports the tubes in a horizontal direction but allows for vertical movement of the tube relative to the tube sheet, whilst providing a fluid tight seal around the tube to seal the tube relative to the tube sheet. The benefit of this previous solution was that the stuffing boxes were located in a relative cold (less than approximately 650 degrees Celsius) environment, suitable for the packing / sealing material of the stuffing box. But the solution had drawbacks such as fresh feed bypassing all reforming steps in case of a stuffing box leakage; and creep buckling of the tubes and lower tube sheet, as the relative hot lower tube sheet and the relative hot tubes themselves had to support the weight of the tubes. The risk of these two major drawbacks could be minimized if the sealing solution, is moved from the top tube sheet to the bottom tube sheet. In this case, the tubes would be expanding downwards through the lower tube sheet and risk of creep buckling due to the load of the tube bundle would be minimized or even fully avoided. Furthermore, fresh feed by-pass would be avoided in case of leakage as any leaking fluid through the sealing around the tubes in the lower tube sheet would be leaking fluid which was already partly reformed by the catalyst within the tubes. But a new risk is however introduced if the sealing solution is moved from the top tube sheet to the bottom tube sheet: The stuffing boxes are now located in the relative hot end of the catalytic heat exchange reactor (more than approximately 650 degrees Celsius), with temperatures exceeding the sealing I packing rope design temperatures. Hence, there is a need for a solution to this problem.

[0009] A process and reactor in which a catalyst is in indirect contact with a heat exchanging medium is known from EP0271299. This citation discloses a reactor and process that combines steam reforming and autothermal reforming. The steam reforming zone arranged in the lower region of the reactor comprise a number of tubes with catalyst disposed inside while on the upper region of the reactor an autothermal reforming catalyst is disposed outside the steam reforming tubes. EP-A-1 106 570 discloses a process for steam reforming in parallel connected tubular reformers (reactors) comprising a number of steam reforming tubes and being heated by indirect heat exchange. The catalyst is disposed in one reactor outside the steam reforming tubes and inside the steam reforming tubes in the other reactor.

[0010] WO0156690 describes a heat exchange reactor including an outer shell provided with process gas inlet and outlet ports, a plurality of reactor tubes supported at their upper ends, header means for supplying process gas from said header inlet port to the upper ends of the reactor tubes, said means including two or more primary inlet headers disposed across the upper part of said shell, each primary inlet header having a depth greater than its width, whereby said tubes are supported, relative to the shell directly or indirectly by said primary inlet headers.

[0011] EP1048343A discloses a heat-exchanger type reactor which has a plurality of tubes holding a catalyst, a shell section through which a heat-transfer medium is passed to carry out heat-transfer with a reaction fluid in said tubes, and upper and lower tube sheets, the upper ends of said tubes being joined to said upper tube sheet by way of first expansion joints fixed to the upper side of said upper tube sheet, the lower ends of said tubes being fixed directly to the floatable lower tube sheet, a floatable room being formed which is partitioned by said lower tube sheet and an inner end plate (inner head) joined to the lower side thereof and has an opening in the lower part, and said opening being joined by way of a second expansion joint to a tube-side outlet to the outside of the reactor. Due to the conditions of the catalytic reaction process, the heat exchange reactor must have a structure which can absorb the differential thermal expansion between the tubes and the housing due to the temperature difference between them. Also the structure must be able to absorb the differential thermal expansion between the tubes, which is caused by the temperature difference between tubes, produced by the difference in reaction and heat-transfer conditions between tubes, the difference being due to the tolerance in tube outer diameter in the reactor, the difference in catalyst packing density in each tube, the difference in catalyst activity, the uneven distribution of a reaction gas flowing through the tubes, the uneven distribution of a heat-transfer medium flowing through the shell section etc.

[0012] Conventional heat exchange reactors with tubes fixed in tube heads and the tube heads fixed to the reactor housing cannot meet these requirements because they cannot cope with the differential thermal expansion between the housing and the tubes or between the tubes. In EP 1048343 the thermal expansion can be absorbed by first expansion joints for each tube and a second expansion joint in connection to a floating lower tube head. Thus, the solution to the expansion problems disclosed by EP 1048343 demands for both first and a second expansion joints and further the first expansion joints must have sufficient strength that can bear the load due to the weight of the tubes, catalysts, and the lower tube head a well as the pressure difference between tube side and shell side. Further the second expansion joint of EP 1048343 are desirably isolated from the reaction fluid or the heat exchange fluid if these have temperatures of for example 500°C or above, because it is a problem to provide gas tight joints for such high temperatures. Another solution is to accept a slight leak of gas at the expansion joint, by providing e.g., a labyrinth seal. This is however not acceptable for all applications.

[0013] It is an object of the present invention to provide a heat exchange reactor which solves the mentioned problems, the expansion problems and especially the problem of too high temperatures around and within the stuffing boxes as mentioned in the above. A further object is to provide an improved heat exchange reactor which can operate at high temperatures but still have a gas tight sealing between the tubes and the tube sheets. The present invention solves the above-described problems by a catalytic heat exchange reactor according to claim 1 comprising a cooled sandwich type tube sheet comprising sliding tube supports and where said cooled sandwich type tube sheet is adapted to receive a heat transfer fluid to cool the sliding supports. Further benefits of the present inventions are described in the following, as the heat transfer fluid may also provide a gas seal in case of a leaking sliding support, and the temperature of the lower tube sheet is lowered allowing for a possible reduction in tube sheet thickness.

[0014] In an embodiment of the invention, a heat exchange reactor for carrying out endothermic or exothermic reaction comprises a housing with a plurality of heat transfer tubes arranged from an upper part to a lower part of the housing. Catalyst beds are disposed inside, outside, or both inside and outside these heat transfer tubes and the arrangement of the tubes within the housing allows for the supply or removal of heat to or from the catalyst beds. To support the tubes and provide separation of the process fluids, a first tube sheet is located within the upper part of the housing, supporting the upper part of the heat transfer tubes; and a second tube sheet is located within the lower part of the housing, supporting the lower part of the heat transfer tubes. Each of the first and the second tube sheet have bores adapted to support each of the heat transfer tubes. The bores have an area large enough for the tubes to pass through them, the exact size of the bore areas is adapted to allow for tolerances of the bores, the tubes and production I installation to mention some of the design-factors. An important feature of the invention is that at least one of the tube sheets comprises sliding supports for each of the heat transfer tubes. The sliding supports allows each of the heat transfer tubes to move up- and down-wards (especially due to difference is temperature expansion of the materials) individually relative to the tube sheet, while supporting each heat transfer tube in a side-wards direction, keeping the heat transfer tubes in their horizontal position relative to the tube sheet. At least one of the tube sheets is a sandwich tube sheet with an inner void. The inner void of said tube sheet is adapted to receive a heat transfer fluid (such as steam). Hence, the heat transfer fluid is able to transfer heat from the tube sheet and the sliding supports to the heat transfer fluid, thus cooling the tube sheet and the sliding supports. To enable the heat transfer fluid to enter the inner void of the sandwich tube sheet, there is at least one fluid opening to said void from the outside of the housing. This opening may then be connected to piping supplying the heat transfer fluid to the inner void of the sandwich tube sheet. In an embodiment of the invention the second tube sheet which is located within the lower part of the housing is a sandwich tube sheet as described in the above. This has the advantage as before mentioned that the heat transfer tubes are supported at their upper end and thus the plurality of heat transfer tubes as well as the second tube sheet is less subjected to creep, as the weight of the tubes is supported by the first tube sheet at the upper end of the heat transfer tubes. The upper end of the heat transfer tubes may be fixed to the first (upper) tube sheet, for instance by welding, also ensuring a fluid tight connection between the first tube sheet and the heat transfer tubes.

[0015] The sandwich tube sheet may in an embodiment comprise an upper plate and a lower plate. The plates may be planar, ellipsoid or any shape as best suited to the design criteria. Furthermore, in an embodiment of the invention, the mentioned upper and lower plate of the sandwich tube sheet may be fixed together in connection areas. These embodiments have the advantage that on the one hand, the sandwich tube sheet may be manufactured at low cost, using plates. The plates may be fixed together fluid tight. This may be done for instance by welding around the circumference of the plates with or without a spacing material between them. Also, internal connection areas may be comprised in the sandwich tube sheet. These internal connection areas may increase the structural strength of the sandwich tube sheet and they may also be designed and arranged to ensure an optimal fluid flow of the heat transfer fluid within the void of the sandwich tube sheet for cooling each of the sliding supports. More specifically, the sandwich tube sheet may comprise dedicated fluid guides within the inner void. These guides may be adapted to guide the heat transfer fluid within the void, and they may be connected to either one of the upper or lower inner surface of the sandwich tube sheet or they may be connected to both the upper and lower inner surface of the sandwich tube sheet.

[0016] To further ensure an optimal fluid flow of the heat transfer fluid, an embodiment of the invention comprises both a first and a second fluid opening in the sandwich tube sheet. One fluid opening allows supply of the heat transfer fluid, and the other opening is adapted to allow the heat transfer fluid to exit from inner void of the sandwich tube sheet from I to the outside of the housing. This embodiment allows for a pre-calculated flow of heat transfer fluid to the sandwich tube sheet to ensure sufficient cooling of the sliding supports. It is to be understood that there may also be embodiments where the heat transfer fluid may exit from the sandwich tube sheet to the inner part of the heat exchange reactor if it suits the process or maybe has insignificant impact on the process within the heat exchange reactor. Further, there may be more than one inlet and there may be more than one outlet. In an embodiment of the invention, the first fluid opening is arranged sidewards opposite to the second fluid opening relative to the sandwich tube sheet. One benefit of this arrangement is that the heat transfer fluid thus flows from one “end” of the sandwich tube sheet to the other “end”. But it is to be understood that the fluid openings may be arranged in any position and orientation as best fits the process, the equipment, the surroundings, or other needs.

[0017] In an embodiment of the invention, the sliding supports comprise piston rings arranged within the sliding supports and around the heat transfer tubes. The piston rings are adapted to allow the heat transfer tubes to move upwards and downwards within the sliding supports as is the purpose of the sliding supports; and the piston rings may be adapted to allow for a calculated amount of heat transfer fluid to exit the inner void along each heat transfer tube along each sliding support, to thereby apply cooling of the stuffing boxes.

[0018] In another embodiment of the invention, the sliding supports comprise stuffing boxes adapted to form a fluid tight seal around each heat transfer tube within the sliding supports. The stuffing boxes comprise a sealing or packing material as well known in the art, for instance for the like heat exchange reactors with stuffing boxes arranged on the upper tube sheet which is located in a cooler zone of the reactor. As discussed in the above, the stuffing boxes are cooled via the heat transfer fluid entering the void within the sandwich tube sheet. But in another embodiment, the stuffing boxes may be further cooled as they are adapted to allow for a calculated amount of heat transfer fluid to exit the inner void along each heat transfer tube along each sliding support, thus cooling the stuffing boxes and ensuring that the packing / sealing material remains intact. In a further embodiment, the stuffing boxes are purge cooled, such that they are adapted to allow for heat transfer fluid to flow around each of the stuffing boxes and thus cooling them. It is to be understood that a calculated amount of heat transfer fluid may in some cases enter the inside of the heat exchange reactor, for instance if the heat transfer fluid is steam and if a certain amount of steam is not interfering with the process within the reactor. In an embodiment of the reactor, the heat transfer tubes may comprise a bottleneck in the lower part. This bottle neck may serve as a support for an inner grid supporting the catalyst bed within the heat transfer tubes. Furthermore, it may decrease the dimensions of the stuffing boxes and sealings.

[0019] In a further embodiment of the invention, at least one of the tube sheets within the catalytic heat exchange reactor may be heat insulated on at least one side of the tube sheet. This may have the advantage that the tube sheets are not subjected to the highest process temperatures and thus may have less strength, material demand and / or dimensions.

[0020] As well known in the art, the tube bundle can be provided with baffles, for instance of the disc and doughnut type to further enhance the heat transfer between the fluid outside and the fluid inside the tubes.

[0021] Features of the invention

[0022] 1. A catalytic heat exchange reactor for carrying out endothermic or exothermic reactions comprising,

[0023] • a housing

[0024] • a plurality of heat transfer tubes arranged from an upper part to a lower part of the housing and within said housing for the supply or removal of heat in catalyst beds disposed inside, outside, or both inside and outside said heat transfer tubes,

[0025] • a first tube sheet located within the upper part of the housing for supporting the upper part of the heat transfer tubes,

[0026] • a second tube sheet located within the lower part of the housing for supporting the lower part of the heat transfer tubes, the first and the second tube sheet each have bores adapted to support each of the heat transfer tubes, at least one of the tube sheets comprises sliding supports for each of the heat transfer tubes which supports the plurality of heat transfer tubes in a sidewards direction and allows the heat transfer tubes to move up- and down-wards individually relative to the tube sheet, wherein the at least one tube sheet comprising sliding supports is a sandwich tube sheet comprising an inner void adapted to receive a heat transfer fluid and comprising at least one fluid opening to said void from the outside of the housing. 2. A catalytic heat exchange reactor according to feature 1 , wherein the second tube sheet located within the lower part of the housing is the sandwich tube sheet.

[0027] 3. A catalytic heat exchange reactor according to feature 1 or 2, wherein said sandwich tube sheet comprises an upper plate and a lower plate.

[0028] 4. A catalytic heat exchange reactor according to feature 3, wherein said upper and lower plate are fixed together in connection areas.

[0029] 5. A catalytic heat exchange reactor according to feature 1 , wherein said sandwich tube sheet comprises a first and a second fluid opening, the first fluid opening is adapted to let the heat transfer fluid into the inner void from the outside of the housing and the second fluid opening is adapted to let at least a part of the heat transfer fluid out of the inner void to the outside of the housing.

[0030] 6. A catalytic heat exchange reactor according to feature 5, wherein the first fluid opening is arranged sidewards opposite to the second fluid opening relative to the sandwich tube sheet.

[0031] 7. A catalytic heat exchange reactor according to feature 5 or 6, wherein the sandwich tube sheet comprises fluid guides within the inner void adapted to guide the heat transfer fluid from the first fluid opening and around all the sliding supports before the heat transfer fluid exits through the second fluid opening.

[0032] 8. A catalytic heat exchange reactor according to any of the preceding features, wherein the sliding supports comprises piston rings adapted to allow for a calculated amount of heat transfer fluid to exit the inner void along each heat transfer tube along each sliding support.

[0033] 9. A catalytic heat exchange reactor according to any of the preceding features, wherein the sliding supports comprises stuffing boxes adapted to form a fluid tight seal around each heat transfer tube within the sliding support. 10. A catalytic heat exchange reactor according to any of the preceding features, wherein the sliding supports comprises cooled stuffing boxes adapted to allow for a calculated amount of heat transfer fluid to exit the inner void along each heat transfer tube along each sliding support thereby cooling the stuffing boxes.

[0034] 10. A catalytic heat exchange reactor according to any of the preceding features, wherein the sliding supports comprises purge cooled stuffing boxes adapted to allow for heat transfer fluid to flow around each of the stuffing boxes thereby cooling the stuffing boxes.

[0035] 11. A catalytic heat exchange reactor according to any of the preceding features, wherein the lower part of the heat transfer tubes comprises a bottleneck (114), whereby the cross-sectional area of the lower end of the heat transfer tubes is smaller than the cross-sectional area of the heat transfer tubes above the bottleneck.

[0036] 12. A catalytic heat exchange reactor according to feature 11 , wherein the catalyst beds are located inside the heat transfer tubes and said heat transfer tubes each comprise a support (115) located in the lower part of each of the heat transfer tubes above the bottleneck to support the catalyst beds.

[0037] 13. A catalytic heat exchange reactor according to any of the preceding features, wherein at least one of the tube sheets has an ellipsoidal shape.

[0038] 14. A catalytic heat exchange reactor according to any of the preceding features wherein at least one of the first and the second tube sheet is heat insulated on at least one side of the tube sheet.

[0039] The present invention will be discussed in more detail with reference to some embodiments of the invention as shown in the drawings in which:

[0040] Fig. 1 is a bottom-up view of a part of one embodiment of a heat exchange reactor,

[0041] Fig. 2 is a cross section side view of a part of the lower tube sheet of a heat exchange reactor comprising a sliding support and the lower part of a heat exchange tube according to an embodiment of the invention. Fig. 3 is a cross section side view of a part of the lower tube sheet of a heat exchange reactor comprising a sliding support and the lower part of a heat exchange tube according to a further embodiment of the invention.

[0042] Fig. 4 is a cross section side view of a part of the lower tube sheet of a heat exchange reactor comprising a sliding support and the lower part of a heat exchange tube according to a further embodiment of the invention.

[0043] Fig. 5 is a cross section side view of a part of the lower tube sheet of a heat exchange reactor comprising a sliding support and the lower part of a heat exchange tube according to a further embodiment of the invention.

[0044] Position number overview

[0045] 100. heat exch a ng e reacto r

[0046] 101. housing

[0047] 102. heat transfer tube

[0048] 103. first tube sheet

[0049] 104. second tube sheet

[0050] 105. tube sheet bore

[0051] 106. sliding support

[0052] 107. inner void

[0053] 108. upper plate

[0054] 109. lower plate

[0055] 110. connection area

[0056] 111. piston rings

[0057] 112. stuffing box

[0058] 113. cooled stuffing box

[0059] 114. purge cooled stuffing box

[0060] 115. bottle neck

[0061] It is to be understood that the following are only some specific embodiments of the invention. For instance, other dimensions and tube-numbers are a scope of the present invention.

[0062] Catalytic heat exchange reactors are well known in the art. Fig. 1 shows a part of such a heat exchange reactor 100. As mentioned in the above, the heat exchange reactor comprises a housing 101. In Fig. 1 a part of the housing is visible in the bottom-up view of a cut out part of the heat exchange reactor. In the bottom view a part of the second tube sheet 104, the lower tube sheet in the heat exchange reactor, is seen from below. The heat exchange reactor also comprises a first tube sheet 103 not shown in the drawings. Some of the heat transfer tubes 102 are also seen, arranged within the tube sheet bores 105. The bottom part of the heat transfer tubes is visible in this cut out, bottom-up view of Fig 1. It is to be understood, that the numbering is only pointing to a few of the tube sheet bores and heat transfer tubes. Turning to Fig. 2, an embodiment of the invention can be seen in more detail. The side cut view of Fig. 2 shows the bottom part of one of the heat transfer tubes. In this embodiment, the heat transfer tube comprises a bottle neck 115, which decreases the outer diameter of the heat transfer tube lower part. This lower part is arranged within the tube sheet bore of the second tube sheet and protrudes through it. As can be seen, the second tube sheet is a sandwich tube sheet with and upper plate 108 and a lower plate 109. The upper plate and lower plate are fixed together in a number of connection areas 110, which in this detail view serves as the sliding support 106. This all forms an inner void 107 within the second tube sheet, which may comprise a heat exchange fluid symbolised with the large arrows in Fig. 2. As discussed in the above, the sliding support allows the lower part of the heat exchange tube to move up- and down-wards relative to the second tube sheet, while supporting the heat exchange tube against horizontal movement. For this horizontal support and for the purpose of preventing or minimizing leakage of process fluid from above the second tube sheet to below the second tube sheet, along the side of the lower part of the heat exchange tube, this embodiment comprises four piston rings 111. The piston rings have a sliding fit with fine tolerances around the outer surface of the lower part of the heat exchange tube. The piston rings also fit the inner side of the sliding support with fine tolerances - to minimize or prevent fluid leakage. Elements (not shown) prevents the piston rings from escaping from the sliding support. As the sliding support may not be entirely leak proof, the sliding support may be adapted to allow a calculated amount of leakage of heat exchange fluid around the piston rings and along the outer surface of the heat exchange tube. The heat exchange fluid may for instance be steam which in some amounts may be acceptable to add to the process fluid. Thus, the calculated heat exchange fluid leakage forms a steam sealing within the piston ring sliding support. Furthermore, the heat exchange fluid serves the purpose of cooling the second tube sheet as well as the sliding support, enabling the dimensions of the second tube sheet to be reduced. It is to be understood that the heat exchange fluid enters the second tube sheet through at least one fluid opening (not shown on the drawings) to said void from the outside of the housing.

[0063] In a further embodiment of the invention as shown in Fig. 3, instead of piston rings, the sliding support comprises a stuffing box 112. The rest of the details are the same as in Fig. 2. The stuffing box comprises sealing, for instance sealing rope well known in the art, which provides a tighter connection than the piston rings shown and mentioned in Fig. 1. However, if for some reason the stuffing box is not entirely sealed, or if the sealing becomes worn or damaged, the heat exchange fluid provided in the inner void, can form a seal, such as a steam seal, to prevent the flow of process fluid from the upper side of the second tube sheet to the lower side of the second tube sheet. The flow of the heat exchange fluid is again symbolised by the large arrows and the possible “leakage” flow of the heat exchange fluid (such as steam) is symbolised by the stippled arrows. Thus, the embodiment of Fig 3 may provide a tight seal within the sliding support while providing cooling and a protecting fluid seal in case of leakage.

[0064] A further embodiment of the invention is shown in Fig. 4, where there is also a stuffing box, but in this embodiment, it is a cooled stuffing box 113. The cooled stuffing box has the advantage that is cooled by a calculated flow (leakage) of heat exchange fluid such as steam. In Fig. 4 this is shown by the large arrows providing a flow through the connection area and further out along a guide and the side of the lower part of the heat exchange tube. Thus, in this embodiment a calculated part of the heat exchange fluid will flow from the void and into the process area above the second tube sheet, whilst cooling the stuffing box to ensure a long / predicted lifetime of the sealing material.

[0065] Yet a further embodiment of the invention is shown in Fig. 5. This embodiment comprises a purged cooled stuffing box 114, but the details are essentially the same as in the embodiment shown in Fig. 3. The difference is that the stuffing box in forced cooled by a purge of heat exchange fluid flowing around the stuffing box. This embodiment requires at least two fluid openings to the inner void from the outside of the housing, one fluid opening to allow heat exchange fluid to enter the inner void, but also a fluid opening to allow the heat exchange fluid to exit the inner void, hence the purge around the stuffing box. This embodiment thus ensures a calculated flow of heat exchange fluid around the purge cooled stuffing box, thus cooling the sealing within the purge cooled stuffing box to ensure a long / predicted lifetime of the sealing material.

[0066] Should there be a leak in the purge cooled stuffing box the heat exchange fluid will also flow along the lower part of the heat exchange fluid to the upper side of the second tube sheet as in the embodiment shown in Fig. 3, in case of the heat exchange fluid being steam, thus providing a steam flow seal which prevents process fluid to flow from the upper side of the second tube sheet to the lower side of the second tube sheet.

Claims

Claims1. A catalytic heat exchange reactor for carrying out endothermic or exothermic reactions comprising,• a housing• a plurality of heat transfer tubes arranged from an upper part to a lower part of the housing and within said housing for the supply or removal of heat in catalyst beds disposed inside, outside, or both inside and outside said heat transfer tubes,• a first tube sheet located within the upper part of the housing for supporting the upper part of the heat transfer tubes,• a second tube sheet located within the lower part of the housing for supporting the lower part of the heat transfer tubes, the first and the second tube sheet each have bores adapted to support each of the heat transfer tubes, at least one of the tube sheets comprises sliding supports for each of the heat transfer tubes which supports the plurality of heat transfer tubes in a sidewards direction and allows the heat transfer tubes to move up- and down-wards individually relative to the tube sheet, wherein the at least one tube sheet comprising sliding supports is a sandwich tube sheet comprising an inner void adapted to receive a heat transfer fluid and comprising at least one fluid opening to said void from the outside of the housing.

2. A catalytic heat exchange reactor according to claim 1 , wherein the second tube sheet located within the lower part of the housing is the sandwich tube sheet.

3. A catalytic heat exchange reactor according to claim 1 or 2, wherein said sandwich tube sheet comprises an upper plate and a lower plate.

4. A catalytic heat exchange reactor according to claim 3, wherein said upper and lower plate are fixed together in connection areas.

5. A catalytic heat exchange reactor according to claim 1 , wherein said sandwich tube sheet comprises a first and a second fluid opening, the first fluid opening is adapted to let the heat transfer fluid into the inner void from the outside of the housing and the second fluid opening is adapted to let at least a part of the heat transfer fluid out of the inner void to the outside of the housing.

6. A catalytic heat exchange reactor according to claim 5, wherein the first fluid opening is arranged sidewards opposite to the second fluid opening relative to the sandwich tube sheet.

7. A catalytic heat exchange reactor according to claim 5 or 6, wherein the sandwich tube sheet comprises fluid guides within the inner void adapted to guide the heat transfer fluid from the first fluid opening and around all the sliding supports before the heat transfer fluid exits through the second fluid opening.

8. A catalytic heat exchange reactor according to any of the preceding claims, wherein the sliding supports comprises piston rings adapted to allow for a calculated amount of heat transfer fluid to exit the inner void along each heat transfer tube along each sliding support.

9. A catalytic heat exchange reactor according to any of the preceding claims, wherein the sliding supports comprises stuffing boxes adapted to form a fluid tight seal around each heat transfer tube within the sliding support.

10. A catalytic heat exchange reactor according to any of the preceding claims, wherein the sliding supports comprises cooled stuffing boxes adapted to allow for a calculated amount of heat transfer fluid to exit the inner void along each heat transfer tube along each sliding support thereby cooling the stuffing boxes.

10. A catalytic heat exchange reactor according to any of the preceding claims, wherein the sliding supports comprises purge cooled stuffing boxes adapted to allow for heat transfer fluid to flow around each of the stuffing boxes thereby cooling the stuffing boxes.

11. A catalytic heat exchange reactor according to any of the preceding claims, wherein the lower part of the heat transfer tubes comprises a bottleneck (114), whereby the cross-sectional area of the lower end of the heat transfer tubes is smaller than the cross-sectional area of the heat transfer tubes above the bottleneck.

12. A catalytic heat exchange reactor according to claim 11, wherein the catalyst beds are located inside the heat transfer tubes and said heat transfer tubes each comprise asupport (115) located in the lower part of each of the heat transfer tubes above the bottleneck to support the catalyst beds.

13. A catalytic heat exchange reactor according to any of the preceding claims, wherein at least one of the tube sheets has an ellipsoidal shape.

14. A catalytic heat exchange reactor according to any of the preceding claims wherein at least one of the first and the second tube sheet is heat insulated on at least one side of the tube sheet.

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