Shell-and-tube heat exchanger, heat exchange method, and use of a heat exchanger

Abstract

Aspects of the present invention relate to a shell-and-tube heat exchanger (101), a method of using such a heat exchanger, and a hydrocarbon cracking furnace system including such a heat exchanger. The shell-and-tube heat exchanger includes at least a spiral baffle (7) arranged to provide a helical flow path through a shell body (103), and an outlet collector pipe (4) supporting the spiral baffle and extending substantially coaxially within the shell body, the outlet collector pipe (4) being attached at one end to and passing through a second tube sheet (106) defining the shell body (103), the outlet collector pipe (4) being separated at an opposite end from a first tube sheet (105) by a gap that allows a shell-side fluid (F2) to exit the shell body (103).

Description

Technical Field

[0001] The present disclosure relates to a shell-and-tube heat exchanger, a method for heat exchange between a first fluid and a second fluid, and a method of using the heat exchanger as a transfer line exchanger in a hydrocarbon cracking furnace system.

Background Art

[0002] Shell-and-tube heat exchangers constitute general-purpose heat exchangers, for example, due to their wide applicability within a wide range of pressures and temperatures. Shell-and-tube heat exchangers are commonly used in applications in the power industry and the petrochemical industry. Usually, a shell-and-tube heat exchanger includes one or more heat exchange tubes installed in a cylindrical shell that exchanges heat between two fluids, where a first fluid flows through the heat exchange tubes themselves while a second fluid flows outside the heat exchange tubes.

Summary of the Invention

Problems to be Solved by the Invention

[0003] For example, a common problem with known shell and tube heat exchangers of the type in which the shell space contains longitudinal and / or transverse baffles is that the heat exchanger exhibits a non-uniform flow distribution, particularly on the shell side of the heat exchanger. A non-uniform flow distribution region within one side can result in non-uniform and slow or inadequate heat transfer to the fluid on the other side. Non-uniform flow distribution and the attendant non-uniform heat exchange are typically the result of flow path turbulence within the shell. The turbulence is typically manifested in the form of vortices that occur when the fluid passes over or under the trailing edge of the baffle. Alternatively or in addition, the flow profile within the shell can be particularly disrupted when the fluid enters or exits the shell, for example at the inlet or outlet. As a result of one or more of the above disadvantages, the properties of the product and / or feedstock or process medium on the tube side and / or shell side can deteriorate. Alternatively or in addition, the performance of the heat exchanger can decrease, for example due to fouling resulting from non-uniform distribution of the process flow or degradation of the process medium, or due to overheating resulting from sub-optimal heat transfer.

[0004] In order to improve the flow distribution, the provision of an exchanger with a scroll or spiral baffle has been proposed. U.S. Patent Application Publication No. 2009 / 301699 discloses a heat exchanger comprising a shell having a fluid inlet and a fluid outlet, and a plurality of baffles attached to the shell for guiding the fluid through the shell in a spiral flow pattern. U.S. Patent Application Publication No. 2008 / 80190593 discloses a one-shell pass and multiple-shell pass shell-and-tube heat exchanger comprising a shell having a fluid inlet and a fluid outlet with a discontinuous spiral baffle, e.g., joined baffle portions. As a disadvantage, the confirmation of a uniform flow distribution within the shell of a heat exchanger of the type disclosed in U.S. Patent Application Publication No. 2009 / 301699 and U.S. Patent Application Publication No. 2008 / 80190593 remains difficult, especially around the centerline, e.g., along the central portion of the shell in the immediate vicinity of the opposing ends of the joined baffles. In order to improve the flow distribution, it has been proposed to attach the baffle to a central support. Chinese Patent Application Publication No. 100386586C discloses a heat exchanger comprising a shell having a fluid inlet and a fluid outlet, and a central core to which a baffle is attached for providing a spiral flow path around the central core. However, a heat exchanger having such a central core remains disturbed near the inlet / outlet of the shell, and further, the central core is supported by adjacent tube sheets and cannot expand freely, and thus remains subject to mechanical stresses due to thermal expansion, which are difficult to manage, as a result of the temperature difference between the shell-side wall and the tube-side wall.

[0005] It is an object of the present invention to provide a shell-and-tube heat exchanger that alleviates one or more of the above problems. Alternatively or in addition, it is an object of the present invention to provide a shell-and-tube heat exchanger that has an improved flow distribution and / or improved performance, e.g., with respect to fouling, compared to known shell-and-tube heat exchangers.

Means for Solving the Problems

[0006] Aspects of the present invention relate to a shell and tube heat exchanger. During operation, the shell and tube heat exchanger facilitates heat exchange between the tube side fluid and the shell side fluid. The shell and tube heat exchanger includes a first tube sheet, a second tube sheet, and a shell body. A shell side inlet nozzle is attached to the shell body. Opposing end portions of the shell body are defined by the first tube sheet and the second tube sheet. The shell and tube heat exchanger further includes one or more heat exchange tubes. The one or more heat exchange tubes extend from the first tube sheet through the shell body to the second tube sheet, thereby providing a fluid connection portion through which a fluid, for example the tube side fluid, passes across the shell body through the heat exchange tubes.

[0007] The shell and tube heat exchanger further includes a spiral baffle. The spiral baffle is provided between the tube sheets inside the shell body and follows a spiral trajectory whose center of rotation is substantially aligned with the center line of the shell body. Usually, the one or more heat exchange tubes pass through the spiral baffle. The spiral baffle is arranged to provide a spiral flow path through the shell body towards the first tube sheet downstream of the shell side inlet nozzle.

[0008] Furthermore, the shell and tube heat exchanger includes an outlet collector pipe. The outlet collector pipe extends substantially coaxially within the shell body, that is, the center line of the outlet collector pipe extends substantially aligned with the center line of the shell body. The outlet collector pipe supports the spiral baffle at least substantially along the entire length of the spiral baffle such that a spiral flow path is guided along the outer surface of the outlet collector pipe.

[0009] The outlet collector pipe is attached to the second tube sheet and passes through the second tube sheet. The outlet collector pipe is separated from the first tube sheet by a gap on the downstream side of the spiral flow path. It is preferable that the outlet collector pipe is separated from the first tube sheet. Due to the gap, the shell-side fluid can enter the collector pipe inlet facing the first tube sheet across the gap during operation. The shell-side fluid can pass through the outlet collector pipe and exit the shell body through a shell-side outlet nozzle provided, for example, at the end of the outlet collector pipe on the opposite side of the collector pipe inlet.

[0010] The shell-and-tube heat exchanger provided with the spiral baffle and the outlet collector pipe according to the present invention is advantageous in improving the velocity distribution, reducing the size and / or number of vortices, and / or reducing the size and / or number of stagnant regions in the shell-and-tube heat exchanger during operation, particularly in the shell-side space.

[0011] Improvement of the velocity distribution on the shell side and / or reduction of the stagnant regions and vortices reduce the degradation of the process medium, for example, the degradation of a temperature-sensitive medium such as the high-temperature feedstock of a hydrocarbon cracking furnace. Until the conversion rate of the feedstock becomes high enough to form coke deposits on the high-temperature tube surface, by exchanging heat with the tube-side fluid, such a high-temperature feedstock can be overheated in the low-velocity region and the relative stagnant regions caused by vortices, leading to fouling of the heat exchanger, resulting in a decrease in efficiency and ultimately requiring cleaning of the heat exchanger. Furthermore, improvement of the flow rate distribution improves the heat transfer between the shell-side fluid and the tube-side fluid, and thus, the efficiency of the shell-and-tube heat exchanger is improved and the device is downsized. Alternatively or in addition, the outlet collector pipe according to the present invention enables free thermal expansion or contraction during operation, for example, due to the thermal gradient between the tube and the outlet collector pipe. For this reason, the expansion bellows of the outlet collector pipe can be omitted, simplifying the manufacturing process. Since the bellows in the outlet collector pipe tend to get dirty and disrupt the normal flow profile, it can further adversely affect the performance of the shell-and-tube heat exchanger.

[0012] A further aspect of the present invention relates to a method of heat exchange between a first fluid and a second fluid, in which method the tube-side fluid is conducted through one or more of the heat exchange tubes of the shell-and-tube heat exchanger according to the present invention, and the shell-side fluid is conducted through the shell body of the shell-and-tube heat exchanger according to the present invention.

[0013] The heat exchanger and the heat exchange method can be particularly advantageously used in chemical industry applications, preferably in hydrocarbon cracking applications, for example, to rapidly and effectively cool a cracked hydrocarbon process stream exiting from a hydrocarbon cracking unit. For example, in an advantageous embodiment, the shell-and-tube heat exchanger is used as a transfer line exchanger to cool the cracked hydrocarbon process vapor from the radiant coil of the cracking furnace. Accordingly, the present invention further relates to a hydrocarbon cracking furnace system comprising the shell-and-tube heat exchanger according to the present invention, and to a method of using the shell-and-tube heat exchanger according to the present invention as a transfer line exchanger in a hydrocarbon cracking furnace system for the production of, for example, ethylene or other monomers. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] These and other features, aspects and advantages of the apparatus, system, use and method of the present invention will be further understood from the following description, the appended claims and the accompanying drawings.

[0015]

Fig. 1A

Fig. 1B

Fig. 2A

Fig. 2B

Fig. 3

Fig. 4

Best Mode for Carrying Out the Invention

[0016] The terms used to describe specific embodiments are not intended to limit the present invention. As used herein, the singular forms of "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. The term "and / or" includes any and all combinations of one or more of the associated listed items. The terms "comprising" and / or "including" are understood to specify the presence of the described features, but not to preclude the presence or addition of one or more other features. When a particular step of a method is described as following another step, this step can directly follow the said another step or, further, one or more intermediate steps may be carried out before performing the particular step, unless otherwise specified. Similarly, when a connection between structures or elements is described, this connection may be made directly or through intermediate structures or elements, unless otherwise specified.

[0017] The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. In the drawings, the absolute and relative sizes of systems, elements, layers, and regions may be exaggerated for clarity. Embodiments may sometimes be described with reference to schematic and / or cross-sectional views of idealized embodiments of the present invention and intermediate structures. In the specification and drawings, like reference numerals refer to like elements throughout. Related terms and their derivatives should be construed to refer to the orientation as shown in the drawings as described or discussed. These related terms are for convenience of explanation and do not require the system to be constructed or operated in a particular orientation, unless otherwise specified.

[0018] FIG. 1A is a side view showing an embodiment of a shell-and-tube heat exchanger 101, and a part of the shell body 103 facing the viewer is omitted so that the interior can be seen. FIG. 1B is a side cross-sectional view taken along line A-A of the embodiment shown in FIG. 1A. In the illustrated embodiment, a first tube sheet 105, a second tube sheet 106, and a shell body 103 having a shell-side inlet nozzle 6 are provided. Opposing end portions of the shell body 103 are defined by the first tube sheet 105 and the second tube sheet 106. The shell-and-tube heat exchanger further includes one or more heat exchange tubes 5 extending from the first tube sheet 105 to the second tube sheet 106 through the shell body 103. The shell-and-tube heat exchanger further includes a spiral baffle 7, an outlet collector pipe 4 having a collector pipe inlet 8, and a shell-side outlet nozzle 3. The spiral baffle 7 follows a spiral locus whose center of rotation is substantially aligned with the center line of the shell body. As shown, the spiral baffle 7 is arranged, for example, to provide a spiral flow path for the shell-side fluid F2 to flow through the shell body 103 toward the first tube sheet 105 on the downstream side of the shell-side inlet nozzle 6.

[0019] Typically, the spiral baffle 7 extends at least one complete 360° rotation, a so-called pitch. By at least one complete rotation, it is ensured that the flow path passes along a helical locus along each of the one or more heat exchange tubes 5. As illustrated, for example, the spiral baffle 7 preferably has a plurality of rotations, for example five or more rotations, for example within a range of 2 to 25 rotations or within a range of 5 to 20 rotations. Generally, the more rotations there are, the higher the overall heat exchange between the tube-side fluid and the shell-side fluid, but the manufacturing complexity increases. Further, the shell-and-tube heat exchanger 101 includes an outlet collector pipe 4 that extends substantially coaxially within the shell body to support the spiral baffle 7. The spiral baffle 7 is preferably supported along the length of the spiral baffle by the outlet collector pipe 4, for example the outer surface of the outlet collector pipe 4, so that the spiral flow path is guided along the outer surface of the outlet collector pipe 4. The baffle preferably extends to the shell body 103, for example to reduce the leakage flow of the shell-side fluid F2 between the baffle and the inner wall of the shell body 103. As illustrated, the baffle is not directly connected to the shell, that is, it is separated from or not directly attached to the shell body 103. One or more heat exchange tubes preferably extend through the spiral baffle. These heat exchange tubes are preferably arranged in a plurality of layers surrounding the outlet collector pipe 4 and extending towards the inner wall of the shell body 103 so as to occupy the available space between the inner wall of the shell body and the outer wall of the outlet collector pipe as much as possible.

[0020] As shown, for example, the outlet collector pipe 4 has a collector pipe inlet 8 and a shell side outlet nozzle 3 provided at opposite ends of the outlet collector pipe 4, and the collector pipe inlet 8 and the shell side outlet nozzle 3 are provided with a fluid connection portion along the hollow interior of the outlet collector pipe between the collector pipe inlet 8 and the shell side outlet nozzle 3. By attaching the outlet collector pipe 4 to the second tube sheet 106 and passing through the second tube sheet 106, the end portion of the outlet collector pipe 4 having, for example, the collector pipe inlet 8 is separated from the first tube sheet 105 by a gap on the downstream side of the spiral flow path. Due to this gap, the shell side fluid F2 can enter the collector pipe inlet 8 facing the first tube sheet 105 across the gap and exit the shell body 103 through the shell side outlet nozzle 3 provided at the end portion of the outlet collector pipe 4 on the opposite side of the collector pipe inlet 8. As shown, for example, by the outlet collector pipe 4 passing through the second tube sheet 106, it is recognized that the tube side fluid F1 can exit the shell side without causing overheating on the shell side of the heat exchanger and dead zones, vortices or stagnant regions that can cause subsequent fouling.

[0021] As shown in FIGS. 1A and 1B, the shell and tube heat exchanger is preferably mounted vertically. More preferably, the second tube sheet 106 is provided above the first tube sheet 105.

[0022] The outlet collector pipe 4 is connected to one tube sheet, preferably the uppermost tube sheet in the case of the vertical direction, and is separated from the other tube sheet. Therefore, for example, due to the thermal gradient between the outlet collector pipe 4 and the outer wall of the heat exchange tube 5 during operation, it is advantageous that it can expand or contract freely. For this reason, advantageously, the expansion bellows for the outlet collector pipe 4 can be omitted. By supporting the baffle by the outlet collector pipe 4 which is connected to one tube sheet while leaving the baffle separated from the shell body 103, free thermal expansion in the direction between the opposing tube sheets 105, 106 becomes possible.

[0023] In contrast, such a bellows is necessary to enable thermal expansion in an embodiment where the outlet collector pipe 4 is connected to the shell-and-tube heat exchanger 101 at both ends, for example, to both tube sheets. The bellows in the outlet collector pipe 4 tends to become fouled along the spiral flow path and within the outlet collector pipe 4, and / or disrupt the flow profile of the shell-side fluid F2, for example, and thus can further adversely affect the performance of the heat exchanger.

[0024] The shell-side inlet nozzle 6 is preferably arranged to inject the flow of the shell-side fluid F2 near or along the second tube sheet 106. For this reason, the shell-side inlet nozzle 6 is preferably attached adjacent to or in the immediate vicinity of the second tube sheet 106 so as to inject the shell-side fluid F2 into the first pitch of the spiral baffle 7, for example, as shown in the drawing. Alternatively, the shell-side fluid F2 may be injected into the space upstream of the spiral baffle 7. By injecting the shell-side fluid F2 into the first pitch of the spiral baffle 7, the formation of a dead volume or a dead space between the second tube sheet 106 and the baffle is suppressed.

[0025] These features will be described in more detail below with reference to FIGS. 1A to 3 together with other features or further features.

[0026] One or more heat exchange tubes extending from a first tube sheet 105 to a second tube sheet 106 across a shell-side space 108 through a shell body 103 typically pass through a spiral baffle 7, for example, through one or more corresponding holes provided in the spiral baffle 7. Similarly, it is understood that a shell-and-tube heat exchanger 101 preferably includes a plurality of heat exchange tubes 5. Only a part of the heat exchange tubes 5 is shown in order to facilitate understanding of the internal structure of the shell-and-tube heat exchanger 101. Instead, the presence of a plurality of tubes may be inferred from a plurality of holes 21 having a size and shape corresponding to one or more of the heat exchange tubes 5 shown. See, for example, FIG. 2A. The tubes are preferably axially aligned. For this purpose, the spiral baffle preferably has a number of holes of matching size and arrangement within each pitch such that one or more tubes can follow an essentially straight path between the first tube sheet and the second tube sheet. Alternatively, the heat exchange tubes 5 may be formed around the spiral baffle 7. For example, straight heat exchange tubes are provided without U-turns, bends, and / or tube joints, which is advantageous for reducing the pressure drop of each heat exchange tube and / or improving the fluid velocity profile inside the heat exchange tube, i.e., on the tube side, and improving the fluid velocity profile in contact with the outer surface of the heat exchange tube, i.e., on the shell side. The shell-and-tube heat exchanger according to the present invention is particularly useful as a device in a hydrocarbon cracking furnace system, in which case it is preferably configured to transfer heat from the cracked hydrocarbon product to the hydrocarbon feedstock supplied to the radiant coil of the hydrocarbon cracking furnace, as shown, for example, in FIG. 4. The cracked hydrocarbon product gas (tube-side fluid) generally contains coke particles that may cause erosion. To prevent erosion, straight tubes without U-turns, bends, and / or tube joints are preferred. As shown in FIGS. 1A and 1B, it is even more preferred that there is only one tube pass such that coke particles enter the heat exchanger from one end and exit from the other end without bending.

[0027] Similarly, it is understood that the heat exchange tubes are preferably uniformly distributed essentially parallel to the outlet collector pipe 4 around the outlet collector pipe 4. In this regard, reference can be made to FIG. 3 showing a cross-sectional view along plane B-B shown in FIG. 2B. In particular, it can be seen that the heat exchange tubes preferably do not extend inside the outlet collector pipe 4, that is, into the internal space of the outlet collector pipe 4. In other words, it is preferable that the heat exchange tubes 5 are distributed only on the inner side of the shell body and outside the outlet collector pipe.

[0028] As shown overall, the shell-and-tube heat exchanger according to the present invention can be regarded as forming one shell pass configuration for exchanging heat with the tube-side fluid in one countercurrent direction. With this configuration, by enabling so-called temperature cross, it is advantageous that the shell-side outlet temperature exceeds the tube-side outlet temperature. For example, when the shell-side inlet temperature is 350 °C, the required shell-side outlet temperature is 600 °C, the tube-side inlet temperature is 800 °C, the tube-side outlet temperature is 550 °C, and the required LMTD (logarithmic mean temperature difference) is 200 °C. It is known that the LMTD can be even lower. This is in contrast to the double shell pass configuration as disclosed in the specification of Chinese Patent Application Publication No. 106839828A and the specification of Chinese Patent Application Publication No. 100386586C, in which heat is exchanged with the tube-side fluid by having two passes on the shell side. Temperature cross is generally not possible in configurations that do not operate in a countercurrent arrangement like the double shell pass configuration disclosed by the specification of Chinese Patent Application Publication No. 106839828A and the specification of Chinese Patent Application Publication No. 100386586C, which includes a parallel flow heat exchange section.

[0029] For example, as shown in the illustration, each heat exchange tube is a continuous tube, and preferably, for example, it is one tube portion extending in length between opposing tube sheets. Alternatively, the heat exchange tube or a part of the heat exchange tube may be formed by joined tube portions, such as halves of longitudinal tubes and / or tube portions. By forming one or more of the heat exchange tubes from a plurality of parts, the manufacturing process can be simplified, for example, by welding the tube portions between successive turns of a spiral baffle. With a continuous heat exchange tube, the roughness of the inner surface of the heat exchange tube can be reduced, and for example, transition portions such as weld portions between joined parts can be avoided. Such a continuous and / or essentially straight heat exchange tube 5 is thought to reduce the contamination rate compared to a rough and / or curved tube.

[0030] It is understood that the position or orientation of the tube side inlet nozzle 1 and / or the tube side outlet nozzle 2 should not be construed as being limited to the positions and / or orientations shown in FIGS. 1A and 1B. For example, in one embodiment, the tube side inlet nozzle 1 and the tube side outlet nozzle 2 are arranged opposite each other so as to form an essentially straight flow path between the tube side inlet nozzle 1 and the tube side outlet nozzle 2. For a given flow, a straight flow path is advantageous in reducing the pressure drop compared to a curved flow path.

[0031] In a preferred embodiment, as shown for example, the shell and tube heat exchanger further comprises a tube side fluid inlet head 102 having a tube side inlet nozzle 1 and a tube side fluid outlet head 104 having a tube side outlet nozzle 2, and the inlet head and the outlet head are provided along opposite end portions of the shell body 103. A first tube sheet 105, also referred to as a tube side inlet tube sheet, separates the head space defined by the tube side fluid inlet head 102 from the shell side space 108 defined within the shell body 103. A second tube sheet 106, also referred to as a tube side outlet tube sheet, separates the head space defined by the tube side fluid outlet head 104 from the shell side space 108. One or more heat exchange tubes 5 are attached to both tube sheets such that the spaces of the tube side fluid inlet head 102 and the tube side fluid outlet head 104 are fluidly connected via at least one heat exchange tube. As shown, one or more heat exchange tubes 5 extend internally from the first tube sheet 105 to the second tube sheet 106 across the shell side space 108 through the shell body 103, defining the tube side space 107 of the shell and tube heat exchanger 101. In an embodiment with a tube side fluid outlet head 104, it is preferred that, as shown for example, an outlet collector pipe 4 is further configured to pass through the tube side fluid outlet head 104. The tube side fluid outlet head 104 may be connected, for example welded, to the wall of the outlet collector pipe 4 or to the shell side outlet nozzle 3. Alternatively, the tube side fluid outlet head 104 may be arranged around the outlet collector pipe or the shell side outlet nozzle.

[0032] In another or further preferred embodiment, the collector pipe inlet has a primary outflow device 15. FIG. 2B is a detailed view showing a cross-section of the shell-and-tube heat exchanger 101 shown in FIG. 1B, which shows such a primary outflow device 15. In other or further preferred embodiments, the shell-and-tube heat exchanger 101 includes a secondary outflow device 9 provided on the first tube sheet 105 opposite the collector pipe inlet 8. Both the primary outflow device and the secondary outflow device suppress the formation of large vortices and stagnant regions at the inlet to the outlet collector pipe. Both outflow devices 15, 9 are arranged to smoothly guide the shell-side fluid F2 to the outlet collector pipe 4 after the shell-side fluid F2 has passed over the end portion of the spiral baffle 7. Both outflow devices 15, 9 further suppress, for example avoid, the formation of vortices and relative stagnant regions, especially in the shell-side region near the first tube sheet 105. Therefore, each outflow device contributes to improving the performance of the heat exchanger by improving the flow distribution of the shell-side fluid F2 along one or more heat exchange tubes 5, especially in the vicinity of the inlet to the outlet collector pipe. The primary outflow device and the secondary outflow device may be provided individually, but the applicant particularly envisages a shell-and-tube heat exchanger 101 provided with both outflow devices 15, 9 in order to further improve the performance of the heat exchanger.

[0033] In one embodiment, the primary outflow device 15 is arranged to guide the shell-side fluid F2 to the outlet collector pipe 4.

[0034] The primary outflow device 15 is preferably formed by an inlet piece that is attached to or formed at the end of an outlet collector pipe 4 having a collector pipe inlet 8. The inlet piece preferably has a side wall that extends outward toward the connection portion between the first tube sheet 105 and the shell body 103 and has a shape like a cone or a trumpet. The conical or trumpet-shaped configuration further contributes to the reduction of dead volume or dead space. The surface of the inlet piece is preferably arranged to smoothly guide the shell-side fluid F2, for example, by having a wing-like cross-section as shown in the drawing. Similar to the spiral baffle 7, the primary outflow device 15 may have one or more holes or passages for one or more heat exchange tubes 5 to extend through the primary outflow device.

[0035] In a preferred embodiment, the primary outflow device is an inlet piece having a shape like a cone or a trumpet so as to smoothly guide the flow of the shell-side fluid F2 to the outlet collector pipe 4. The secondary outflow device 9 is usually a protrusion provided on or formed from the first tube sheet 105 and having a side wall arranged to direct the flow of the shell-side fluid F2 toward the inlet of the outlet collector pipe 4.

[0036] In one embodiment, as shown, for example, in FIGS. 1A, 1B, and 2B, the secondary outflow device 9 can generally be described as a conical protrusion, and the side wall of the protrusion is arranged to direct the flow of the shell-side fluid F2, for example, a lateral flow, along the first tube sheet 105 toward the collector pipe inlet.

[0037] Therefore, in one embodiment, the shell-and-tube heat exchanger includes a secondary outflow device 9 provided on the first tube sheet 105 opposite to the collector pipe inlet 8.

[0038] In a preferred embodiment, the secondary outflow device 9 is a protrusion provided on the first tube sheet 105 at a position facing the collector pipe inlet 8, and the protrusion has a side wall shaped to smoothly guide the flow of the shell-side fluid F2 in a direction along the first tube sheet 105 to the outlet collector pipe 4.

[0039] In another or further preferred embodiment, the secondary outflow device 9 is a conical protrusion.

[0040] Alternatively or in addition, the tertiary outflow device 16 may be provided along the internal connection at the corner between the shell body 103 and the tube-side fluid inlet head 102, and the side wall of the tertiary outflow device is formed to have an inwardly inclined surface arranged to direct the shell-side fluid F2 away from the corner towards the collector pipe inlet.

[0041] In other or further embodiments, for example as shown in the figures, the spiral baffle 7 is a continuous spiral baffle. A continuous spiral baffle may be understood to relate to a spiral baffle provided essentially along the entire length of the baffle, preferably essentially along the entire length of the outlet collector pipe, from the second tube sheet 106 towards the terminal end corresponding to the first tube sheet 105, forming an essentially unbroken continuous spiral flow path. The continuous spiral baffle improves the velocity distribution or essentially reduces vortices and / or stagnant regions along the entire length of the spiral baffle 7 in order to avoid the recirculation that typically occurs downstream of the trailing edge of a segmented or joined baffle and any other type of baffle, such as a conventional impingement baffle. In embodiments with a continuous spiral baffle, the shell-side fluid passes essentially through the baffle, i.e., smoothly along the surface of the baffle (see the white arrowhead arrows in Figure 1A). In non-continuous baffles such as conventional impingement baffles or joined spiral baffles, the fluid flow passes over or under the plates or joined portions to generate recirculation.

[0042] In a preferred embodiment, as shown, for example, in FIG. 2A, a shell and tube heat exchanger comprises a plurality of spiral baffles, such as a primary spiral baffle 7 and a secondary spiral baffle 10. Further spiral baffles follow helical paths whose centers of rotation are aligned with the centerline of the shell body 103 and the outlet collector pipe 4, respectively. Each spiral baffle is supported by the outlet collector pipe 4 along the length of the spiral baffle. Each spiral baffle is shifted relative to the other spirals. By providing a plurality of spiral baffles in the shell and tube heat exchanger, it is possible to form a plurality of helical flow paths separated by the spiral baffles. Providing a plurality of spirals shifted relative to each other can be advantageous over systems with a smaller number of baffles or a single spiral baffle arranged such that the lengths of the entire passage are equal, as will be explained below. As described, the first, i.e., primary spiral baffle 7 generally begins at or near the second tube sheet 106. In a shell and tube heat exchanger with two baffles, the second baffle typically begins about half a pitch away from the second tube sheet with a 180° rotational difference relative to the first spiral. If there are three baffles, the starting points of successive baffles are shifted by 1 / 3 pitch each from the second tube sheet relative to the other baffles, and each baffle rotates at an angle of about 120° about the centerline relative to the other baffles. By providing a plurality of spiral baffles, the velocity distribution is optimized, the formation of larger vortices is suppressed, and / or the residence region is reduced inside the shell side, particularly in the vicinity of the end of the spiral near the inlet to the outlet collector pipe. Each baffle results in a minimum and a maximum velocity of the inlet velocity profile of the collector pipe. The greater the number of baffles applied, the smaller the difference between the maximum and minimum velocities. In particular, the low velocity regions are subject to overheating and degradation of the associated process medium, causing fouling of the heat exchanger. This can be avoided by increasing the number of baffles. Alternatively or in addition, by providing a plurality of spiral baffles, the problem of harmonics is reduced, for example, to avoid destructive vibrations within the shell and tube heat exchanger 101.This occurs when the vibration is at the natural frequency of the system. This is avoided by changing the pitch of the baffles or increasing the number of baffles. Reducing the pitch of the baffles is not always feasible because the allowable pressure drop may be exceeded. In this case, increasing the number of baffles is optional.

[0043] Figures 1A, 1B, 2A, and 2B show a heat exchanger with two spiral baffles, but the inventors further contemplate embodiments with different numbers of spiral baffles, such as one baffle, three baffles, or four baffles.

[0044] In a preferred embodiment, as shown in detail in, for example, FIG. 2A, one or more spiral baffles facing the first tube sheet 105, preferably all end portions 109 of the spiral baffles, have further holes or perforations 20. The end portions having the further holes or perforations 20 allow at least a portion of the shell-side fluid to bypass the end portions. By providing holes or perforations along the end portions, also referred to as the perforated baffle region 109, the shell-side fluid F2 passes over the final edge of the non-perforated spiral baffle before entering the collector pipe inlet 8, as compared to the situation where it passes over the final edge of the non-perforated spiral baffle before entering the collector pipe inlet 8. It has been found that the flow velocity distribution of the shell-side fluid F2, for example, is improved, especially near the collector pipe inlet 8. The total number, size, and / or length of the perforations may vary depending on the number of baffles. The more baffles there are, the fewer the overall perforations may be. Typically, the total number and size of the perforations 20 along a given length of the perforated baffle region are 5 to 50% of the total perforations (for the same length region without such perforations). By providing holes or perforations at the ends of the spiral baffle 7, for example, at 5 to 50% of the total perforations, a portion of the shell-side fluid F2, for example, at least 25 vol%, at least 50 vol% or at least 75 vol%, can flow in a more uniformly dispersed manner around the final edge and towards the collector pipe inlet 8. The total bypass ratio is generally less than 100 vol%, particularly less than 90 vol%, more particularly less than 80 vol%, for example about 75 vol% or less.

[0045] In one embodiment, the spiral baffle or the end portion of the baffle is perforated over a length of at least 5 to 50% of the pitch of the baffle. The pitch of the baffle is the range required to complete a full 360° rotation. This effect is thought to increase as the length of the perforated baffle region 109 increases. In an embodiment with one spiral baffle 7, the optimal length has been found to be about half a pitch. In an embodiment with two shifted spiral baffles, the optimal length has been found to be about 1 / 4 pitch. The length in an embodiment with one baffle is typically at most about one pitch. The length in an embodiment with two baffles is typically at most about half a pitch. In embodiments with different numbers of additional baffles (e.g., a total of four baffles), the length may be adjusted accordingly.

[0046] In one embodiment, as shown, for example, in FIG. 2B, the outlet collector pipe 4 has a heat insulation barrier. Since the shell-side fluid F2 is guided through the outlet collector pipe 4, the heat insulation barrier advantageously reduces heat transfer to the shell-side fluid F2. The heat insulation barrier is preferably provided along the length of the outlet collector pipe 4, that is, from a position in the immediate vicinity of the collector pipe inlet 8 across the second tube sheet 106 towards the shell-side outlet nozzle 3. Most preferably, the heat insulation barrier is provided along substantially the entire length of the outlet collector pipe. Thereby, heat transfer to the tube-side fluid F1 in the shell-side fluid F2 facing the insulation sleeve and / or in a part of the outlet collector pipe 4 extending across, for example, the tube-side fluid outlet head 104 is reduced. In one embodiment, as shown, for example, a tubular inner insulation sleeve 11 is provided along the inner surface of the outlet collector pipe. The insulation sleeve 11 preferably surrounds a heat insulation layer 12. This insulation sleeve 11 is attached to the outlet collector pipe 4 near the collector pipe inlet 8 via a transition piece 13 having a gradually sloping side wall that guides the flow from the inlet to the insulation sleeve. At the opposite end, the shell-side outlet nozzle 3 is connected to the inner insulation sleeve 11 by, for example, a similar transition piece or is connected to the shell-side outlet nozzle 3 (not shown).

[0047] In another or further preferred embodiment, the shell-side inlet nozzle 6 is arranged tangentially to the shell body 103 and is directed such that the inflowing fluid enters the shell body 103 in the same rotational direction as the spiral baffle. By providing the shell-side inlet nozzle 6 tangentially to the shell body 103, it has been found that the flow profile can be further improved, ensuring a smooth flow path from the inlet to the spiral to avoid disturbing the flow, suppressing the formation of vortices, and / or reducing the formation of stagnant regions.

[0048] In a preferred embodiment, for example, in the case of a shell-and-tube heat exchanger in which a tube sheet as shown particularly in FIGS. 1A and 1B is fixed, in order to cope with the difference in thermal expansion between the shell-side wall and the tube-side wall, the shell body 103 has one or more expansion bellows 14. Similar to the configuration in which the tube sheet is fixed, by fixing both tube sheets to the shell body, the manufacturing is simplified and / or the robustness is improved. The heat exchange tubes are generally fixed to the tube sheet. Generally, the position of the bellows is selected so as to avoid accidental rupture. The flexibility of the bellows is an important aspect that requires an appropriate selection of the construction material whose mechanical properties are affected by local operating conditions, such as local temperature. In one embodiment, one or more expansion bellows 14 are preferably arranged immediately downstream of the shell-side inlet nozzle 6, as shown for example. The arrangement of one or more expansion bellows 14 immediately downstream of the shell-side inlet nozzle 6 is such that during operation, the bellows are washed away by the tangential flow pattern generated by the spiral baffle and / or the shell-side inlet nozzle 6 arranged in the tangential direction, so it has been found that the fouling of the bellows is reduced, and thus the accumulation of fouling is reduced. When the shell-side fluid is heated by the tube-side fluid, this region is also a relatively low-temperature region of the heat exchanger, so it is possible to select a different, for example, less expensive bellows material compared to the bellows provided along the relatively high-temperature region of the heat exchanger. In an even lower-temperature region, undesirable conversions of the process medium (shell-side fluid F2), such as degradation, are less of a problem than at the high-temperature end of the heat exchanger. In one embodiment, for example, when a large temperature difference is not predicted, the expansion bellows are omitted.

[0049] A further aspect of the present invention relates to a method of exchanging heat between a first fluid, e.g., a tube-side fluid F1, and a second fluid, e.g., a shell-side fluid F2, using the shell-and-tube heat exchanger 101 according to the present invention. In this method, the tube-side fluid F1 is guided through one or more of the heat exchange tubes of the shell-and-tube heat exchanger according to the present invention, and the shell-side fluid F2 is guided through the shell body 103 of the shell-and-tube heat exchanger according to the present invention.

[0050] The shell-and-tube heat exchanger according to the present invention is particularly advantageous for rapidly cooling a high-temperature process stream, such as a cracked hydrocarbon gas, in a clearly defined and controlled manner. In such an embodiment, the tube-side fluid F1 has a higher temperature than the shell-side fluid F2 when entering the shell-and-tube heat exchanger 101. However, the present invention can be further applied to cool the shell-side fluid. In such an embodiment, the tube-side fluid F1 has a lower temperature than the shell-side fluid F2 when entering the shell-and-tube heat exchanger 101.

[0051] The fluid can be single-phase (gas, liquid or supercritical) or multi-phase (e.g., gas-liquid mixture). It is preferred that the fluid on either side has the same phase, and more preferably that the fluids on both sides are in the gas phase. Figures 1A and 1B show the fluids flowing in a cross-flow / counter-flow arrangement, but it is understood that the shell-and-tube heat exchanger 101 may operate in a co-current arrangement.

[0052] A further aspect of the present invention relates to a cracking furnace system and a method of using the shell and tube heat exchanger according to the present invention as a transfer line exchanger in a hydrocarbon cracking furnace system. A cracking furnace system, such as that disclosed in European Patent Application No. 17176502.7 or U.S. Patent No. 4479869, generally includes a convection section where a hydrocarbon feedstock is preheated and / or partially evaporated and mixed with dilution steam to provide a feedstock-dilution steam mixture. The system includes a radiant section having at least one radiant coil in a firebox where the feedstock-dilution steam mixture from the convection section is converted by pyrolysis at high temperature into product components and by-product components. The system further includes a cooling section having at least one quench exchanger, such as a transfer line exchanger, configured to rapidly quench the product or cracked gas exiting the radiant section to stop pyrolysis side reactions and maintain an advantageous reaction equilibrium in the product.

[0053] It is an object of the present invention to improve the aforementioned system / process. In particular, the present invention addresses the problem of coke formation on the shell side of the heat exchanger. The heat exchanger according to the present invention makes it possible to heat the feedstock-dilution steam mixture without any significant overheating so as to prevent coke formation due to degradation of the feedstock on the shell side of the heat exchanger. Further, since the effluent (cracked hydrocarbon gas) flowing through the tube side usually contains coke particles, a configuration in which the tube sheet is fixed is essential in order to prevent corrosion and clean the tube side. Similar to the configuration in which the tube sheet is fixed, it is impossible to mechanically clean the shell side, and fouling on the shell side should be avoided in any case.

[0054] Such problems are advantageously solved by the shell-and-tube heat exchanger 101 according to the present invention, the method of heat exchange between the first fluid and the second fluid according to the present invention, the method of using the heat exchanger for heat exchange between the first fluid and the second fluid, and / or the hydrocarbon cracking furnace system 1000 as disclosed herein. In particular, such problems are solved by the present invention due to the excellent flow distribution provided in the heat exchanger according to the present invention, without any vortices or stagnant regions that can essentially cause overheating and subsequent fouling on the shell side of the heat exchanger.

[0055] The heat exchanger according to the present invention advantageously forms part of a low-emission hydrocarbon cracking furnace system, the preferred configuration of which may be based on the specification of European Patent Application No. 17176502.7. Accordingly, the heat exchanger may be advantageously employed in an efficient hydrocarbon cracking furnace system that reduces the need for energy supply and, as a result, reduces CO2 emissions.

[0056] In a preferred embodiment, as detailed below with reference to FIG. 4, the heat from the effluent (cracked gas 208) is directly used to preheat the hydrocarbon feedstock 201 before it enters the radiant coil 211.

[0057] FIG. 4 schematically shows an exemplary embodiment of a hydrocarbon cracking furnace system 1000 equipped with a shell and tube heat exchanger 101 according to the present invention. A hydrocarbon cracking furnace system 1000 for converting a hydrocarbon feedstock into cracked gas, as disclosed herein, at least has a furnace convection section 220 having a plurality of convection banks 221 configured to receive and preheat a hydrocarbon feedstock 201, and a radiant section, for example a radiant section / furnace firebox 210, having a radiant coil 211 for cracking the feedstock to form a cracked hydrocarbon gas 208. The shell and tube heat exchanger 101 functions as a primary transfer line exchanger 235 for preheating the hydrocarbon feedstock before it enters the radiant coil 211 and rapidly quenching the product / cracked gas 208 exiting the radiant coil 211. As shown, other components / flows provided in the system include a dilution steam 202, boiler feed water 203, high-pressure steam 204, fuel gas 205, combustion air 206, flue gas 207, radiant coil 211, bottom burner 212, combustion zone (flame) 214, feed preheater 222, high-temperature coil 223, dilution steam superheater 224, high-pressure steam superheater 225, boiler coil 226, steam drum 233, superheater 234, and primary transfer line exchanger 235. Details of the system, its components, its operation, and alternative arrangements can be found in European Patent Application No. 17176502.7. The embodiments and methods shown and described in relation to European Patent Application No. 17176502.7, particularly the embodiments shown in FIGS. 1-7 of European Patent Application No. 17176502.7, are incorporated herein by reference.

[0058] In an embodiment such as that shown in FIG. 4, for example, the system is configured to mix the hydrocarbon feedstock 201 with the diluent steam 202 and preheat it before entering the radiant coil 211. In such an arrangement, the effluent, the so-called cracked gas 208, is directed through the tube-side space 107 of the shell-and-tube heat exchanger 101, which is typically used. While passing through one or more heat exchange tubes 5, heat is transferred to the shell side containing the hydrocarbon feedstock 201 mixed with the diluent steam 202, and thus the feedstock to the radiant coil 211 is directly preheated. As shown, the feedstock to the radiant coil 211 typically contains the hydrocarbon feedstock 201 and the diluent steam 202. As described above, the advantage of the system is to reduce the degradation of the feedstock by avoiding pyrolysis side reactions, for example, by improving heat transfer within the shell-and-tube heat exchanger 101, that is, by reducing the residence area, reducing vortices, and / or improving the velocity distribution of the flow. Further, by preheating the feedstock to the radiant coil using the heat from the shell-and-tube heat exchanger 101, the system improves energy efficiency compared to a system that indirectly uses heat, for example, to generate steam, and thus reduces the need for energy supply, and as a result, advantageously reduces the CO2 emissions of the system.

[0059] From the above, it is understood that in a preferred embodiment, the shell and tube heat exchanger 101 is used to cool the cracked hydrocarbon process stream 208. In a particularly preferred embodiment, the shell and tube heat exchanger 101 is further used to preheat the feedstock to the radiant coil 211. Thus, in one embodiment, in a method of heat exchange between a first fluid and a second fluid, the tube side fluid and the shell side fluid are guided through the tube side space 107 and the shell side space 108 of the heat exchanger, respectively. For example, the tube side fluid F1 is guided through one or more of the heat exchange tubes of the shell and tube heat exchanger according to the present invention, and the shell side fluid F2 is guided through the shell body 103 of the heat exchanger. In a preferred embodiment, one of the tube side fluid F1 and the shell side fluid F2 is the cracked gas 208 exiting from the radiant coil 211 of the hydrocarbon cracking furnace system 1000. As in the embodiment shown in FIG. 4, for example, it is more preferable to directly transfer the heat from the cracked hydrocarbon gas stream 208 to the hydrocarbon feedstock / dilution steam mixture flowing through the radiant coil 211. Thus, in this method, preferably, the cracked gas 208 is guided through the tube side space 107 of the heat exchanger, and the hydrocarbon feedstock / dilution steam mixture is guided to the radiant coil 211 through the shell side space 108 of the heat exchanger.

[0060] As detailed in this specification, the heat exchanger 101 according to the present invention may be particularly advantageously used as a transfer line exchanger in a hydrocarbon cracking furnace system, for example, the hydrocarbon cracking furnace system shown in FIGS. 1 to 5 of European Patent Application No. 17176502.7, the cracking furnace system according to International Publication No. 2018 / 229267 pamphlet, or an embodiment of the cracking furnace system according to International Application No. PCT / EP2020 / 067173, by replacing one or more of the transfer line exchangers. The contents of these applications, particularly the claims, the drawings, and the description of the drawings are incorporated by reference. The hydrocarbon cracking furnace system comprises at least a radiant coil 211 for cracking a hydrocarbon feedstock and a shell-and-tube heat exchanger 101 according to the present invention that is fluidly connected to the radiant coil disposed in the furnace firebox. In a preferred embodiment, the tube-side space 107 and the shell-side space 108 are each fluidly connected to opposite ends of the radiant coil so as to simultaneously cool the hydrocarbon gas flow exiting the radiant coil and preheat the feedstock to the radiant coil.

[0061] For clarity and concise description, features are described herein as part of the same embodiment or as separate embodiments, but it is recognized that the scope of the invention may include embodiments having combinations of all or some of the described features. For example, embodiments are shown with respect to a shell and tube heat exchanger having two consecutive spiral baffles each having a perforated baffle region 109, but alternative methods may be further envisioned by those skilled in the art having the benefit of this disclosure to achieve similar functions and results. The various elements of the described and illustrated embodiments provide certain advantages such as providing a shell and tube heat exchanger having improved flow distribution and / or improved performance in other ways, e.g., with respect to fouling, over known shell and tube heat exchangers. It will be appreciated that any one of the above embodiments or processes may be combined with one or more other embodiments or processes to provide further improvements when finding and adapting configurations and advantages. This disclosure provides particular advantages for cooling a cracked hydrocarbon gas stream 208 and may generally be applied to any use that benefits from improved, preferably substantially perfect, shell side flow distribution and improved heat transfer between fluids.

[0062] In interpreting the appended claims, the term "comprising" does not exclude the presence of other elements or acts than those recited in a given claim, the articles "a" or "an" preceding an element do not exclude the presence of a plurality of such elements, any reference signs in the claims do not limit the scope of the claims, a plurality of "means" may be represented by the same or different (one or more) elements, or implemented structures or functions, and any of the disclosed devices or parts thereof may be combined with further parts or separated into further parts, as appropriate, unless expressly stated otherwise. When one claim refers to another claim, this may indicate synergistic advantages achieved by the combination of their respective features. However, the mere fact that certain means are recited in different claims does not indicate that a combination of these means cannot be used further for advantages. Accordingly, the present embodiment may include all practical combinations of claims, unless expressly excluded by the context, in which each claim may, in principle, refer to any preceding claim.

[0063] The project leading to this application has received funding from the European Union's Horizon 2020 research and innovation programme (H2020-SPIRE-2016) under grant agreement No 723706.

Description of the reference signs

[0064] Shell-and-tube heat exchanger (101) Hydrocarbon cracking furnace system (1000) Tube-side fluid (F1) Shell-side fluid (F2) Tube-side inlet nozzle (1) Tube-side outlet nozzle (2) Shell-side outlet nozzle (3) Outlet collector pipe (4) Heat exchange tube (5) Shell-side inlet nozzle (6) Spiral baffle (7) Collector pipe inlet (8) Secondary outflow device (9) Additional spiral baffle (10) Insulating sleeve (11) Insulating layer (12) Transition piece (13) Expansion bellows (14) Primary outflow device (15) Tertiary outflow device (16) Additional hole or perforation (20) Tube-side fluid inlet head (102) Shell body (103) Tube-side fluid outlet head (104) First tube sheet (105) Second tube sheet (106) Tube-side space (107) Shell-side space (108) Perforated baffle region (109) Hydrocarbon feedstock (201) Dilution steam (202) Boiler feed water (203) High-pressure steam (204) Fuel gas (205) (Combustion) air (206) Flue gas (207) Decomposition gas (208) Boiler water (209a) Partially evaporated boiler water (209b) Radiation section / furnace fire chamber (210) Radiation coil (211) Bottom burner (212) Combustion zone (flame) (214) Furnace convection section (220) Convection bank (221) Supply preheater (222) High-temperature coil (223) Dilution steam superheater (224) High-pressure steam superheater (225) Boiler coil (226) Steam drum (233) Overheat reducer (234) Primary transfer line exchanger / shell and tube heat exchanger (235)

Claims

1. A shell-and-tube heat exchanger (101) for heat exchange between a tube-side fluid (F1) and a shell-side fluid (F2), comprising: a first tube sheet (105); a second tube sheet (106); a shell body (103) to which a shell-side inlet nozzle (6) is attached, the shell body (103) having opposing end portions defined by the first tube sheet (105) and the second tube sheet (106); one or more heat exchange tubes (5) extending from the first tube sheet (105) to the second tube sheet (106) through the shell body (103); a spiral baffle (7) whose rotation center follows a spiral locus substantially aligned with the center line of the shell body, the spiral baffle (7) being arranged to provide a spiral flow path through the shell body (103) toward the first tube sheet (105) downstream of the shell-side inlet nozzle (6); an outlet collector pipe (4) extending substantially coaxially within the shell body, the spiral baffle (7) supporting the spiral baffle (7) along the length of the spiral baffle (7) such that the spiral flow path is guided along the outer surface of the outlet collector pipe (4); wherein the outlet collector pipe (4) is attached to the second tube sheet (106) and passes through the second tube sheet (106); the outlet collector pipe (4) is separated from the first tube sheet (105) by a gap on the downstream side of the spiral flow path, and the shell-side fluid (F2) enters a collector pipe inlet (8) facing the first tube sheet (105) across the gap and exits the shell body (103) through a shell-side outlet nozzle (3) provided at the end portion of the outlet collector pipe (4) opposite the collector pipe inlet (8). A shell-and-tube heat exchanger (101).

2. The collector pipe inlet (8) has a primary outflow device (15) having a shape such as a cone or a trumpet so as to smoothly guide the shell-side fluid (F2) to the outlet collector pipe (4). The shell-and-tube heat exchanger (101) according to claim 1.

3. The spiral baffle (7) is a continuous spiral baffle that provides a continuous spiral flow path along substantially the entire length of the outlet collector pipe (4) from the second tube sheet (106) toward the first tube sheet (105). The shell-and-tube heat exchanger (101) according to claim 1 or 2.

4. The end portion of the spiral baffle (7) facing the first tube sheet (105) has holes or perforations (20) that allow the shell-side fluid (F2) to at least partially bypass the end portion. The shell-and-tube heat exchanger (101) according to any one of claims 1 to 3.

5. It includes a secondary outflow device (9) having a protrusion provided on the first tube sheet (105) facing the collector pipe inlet (8), The protrusion has a shape that smoothly guides the flow of the shell-side fluid (F2) to the outlet collector pipe (4) in a direction along the first tube sheet (105). The shell-and-tube heat exchanger (101) according to any one of claims 1 to 4.

6. The outlet collector pipe (4) has a heat insulation barrier. The shell-and-tube heat exchanger (101) according to any one of claims 1 to 5.

7. It includes one or more additional spiral baffles (10). The shell-and-tube heat exchanger (101) according to any one of claims 1 to 6.

8. The shell-side inlet nozzle (6) is arranged tangentially with respect to the shell body (103). The shell-and-tube heat exchanger (101) according to any one of claims 1 to 7.

9. The shell body (103) has one or more expansion bellows (14). The shell-and-tube heat exchanger (101) according to any one of claims 1 to 8.

10. The opposing ends of the one or more heat exchange tubes (5) open into a tube-side fluid inlet head (102) and a tube-side fluid outlet head (104) respectively, of the shell and tube heat exchanger (101) according to any one of claims 1 to 9.

11. A method for heat exchange between a first fluid and a second fluid, guiding a tube-side fluid (F1) through one or more of the heat exchange tubes (5) of the shell and tube heat exchanger (101) according to any one of claims 1 to 10, and guiding a shell-side fluid (F2) through the shell body (103) of the shell and tube heat exchanger (101) according to any one of claims 1 to 10, a heat exchange method.

12. The heat exchange method according to claim 11, wherein the shell and tube heat exchanger (101) is used as a transfer line exchanger in a hydrocarbon cracking furnace system.

13. The tube-side fluid (F1) is a cracked hydrocarbon process stream exiting from a radiant coil (211) of a cracking furnace system (1000), and the shell-side fluid (F2) contains a hydrocarbon feedstock supplied to the radiant coil (211), preferably a hydrocarbon feedstock-diluent mixture, more preferably a hydrocarbon feedstock-dilute steam mixture, the heat exchange method according to claim 12.

14. A furnace chamber (210) provided with a radiant coil (211) for decomposing a hydrocarbon feedstock, and the shell and tube heat exchanger (101) according to any one of claims 1 to 10, which is fluidly connected to the radiant coil (211) disposed in the furnace chamber A hydrocarbon cracking furnace system (1000) comprising.

15. The shell and tube heat exchanger (101) has a tube-side space (107) and a shell-side space (108) which are fluidly connected to the opposing ends of the radiant coil (211) respectively, and the tube-side space (107) and the shell-side space (108) are configured to cool the hydrocarbon gas stream exiting from the radiant coil (211) simultaneously and preheat the feedstock to the radiant coil (211), the hydrocarbon cracking furnace system (1000) according to claim 14.

16. The shell and tube heat exchanger (101) is essentially vertically mounted, and / or The hydrocarbon cracking furnace system (1000) according to claim 14 or 15, wherein the second tube sheet (106) is disposed above the first tube sheet (105).

Images