ES2668789T3 - Internal baffle to suppress the splash in a heat exchanger of the core type inside the shell - Google Patents

Abstract

A heat exchanger (10) comprising: (a) a defined internal volume within a shell (12); (b) a plurality of spaced apart cores (16, 18, 20) disposed within the internal volume of the shell (12), in which each core is partially submerged in a fluid on the side of the liquid shell, characterized in that (c) splash suppression baffles (28, 30) are arranged within the internal volume to separate the plurality of spaced apart cores (16, 18, 20), in which the splash suppression baffles (28) allow limited distribution of fluid from the side of the liquid shell between each core (16, 18, 20), in which the splash suppression baffles (28) can withstand cryogenic temperatures, in which the splash suppression baffles can withstand and diverting fluid flow from the side of the liquid shell between each core (16, 18, 20), in which the splash suppression baffles (28, 30) are located at the edge of each core (16, 18 , 20) and in which the area between The splash suppression baffles (28, 30) is filled with packing material.

Description

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DESCRIPTION

Internal baffle to suppress the splash in a heat exchanger of the type of cores inside the shell Field of the invention

This invention relates to a baffle for suppressing splashing or sudden movements of fluid in a heat exchanger of the type of cores in the shell.

Background of the invention

Natural gas in its native form must be concentrated before being economically transported. The use of natural gas has increased significantly in the recent past due to its clean, environmentally friendly combustion characteristics. The combustion of natural gas produces less carbon dioxide than any other fossil fuel, which is important, since it has been recognized that carbon dioxide emissions are a significant factor in the creation of the greenhouse effect. It is likely that liquefied natural gas (LNG) is increasingly used in densely populated urban areas with increasing concern about environmental problems.

There are abundant reserves of natural gas throughout the world. Many of these gas reserves are located offshore in places that are inaccessible by land and are considered to be gas reserves in reefs based on the application of existing technology. Existing technical reserves of gas are being recovered faster than oil reserves, making the use of LNG more important to meet the demands of future energy consumption. In liquid form, LNG occupies 600 times less space than natural gas in its gas phase. Since many areas of the world cannot be reached through pipelines due to technical, economic or political limits, the location of the offshore LNG treatment facility and the use of nautical vehicles to directly transport the offshore LNG from the installation of Treatment up to the transport vessel can reduce the initial capital investment and the otherwise non-economic extraction of offshore gas reserves.

Floating liquefaction facilities provide an offshore alternative to offshore liquefaction facilities and an alternative to the expensive underwater pipeline for offshore reserves in reefs. A floating liquefaction facility can be anchored offshore or near, or in, a gas field. It also represents a movable position, which can be relocated to a new place when the gas field is nearing the end of its production life, or when required by economic, environmental or political conditions.

A problem encountered in floating liquefaction vessels is the splashing or sudden movements of the vaporization fluid inside heat exchangers. Splash in a heat exchanger can lead to the production of forces that can affect the stability and control of the heat exchanger. If the vaporization fluid is allowed to splash freely inside the heat exchanger housing, the moving fluid can have an adverse effect on the thermal function of the heat exchanger core. In addition, the cyclic nature of the movement can result in a cyclic behavior in the heat transfer efficiency and, therefore, the treatment conditions of the LNG liquefaction facility can be impacted. These instabilities can lead to a more poor performance of the global installation and can lead to narrower operational envelopes and limits to the available production capacity.

Therefore, there is a need for a splash suppression deflector to reduce the impact of movement within a heat exchanger of the core type within the shell.

Document US5651270 describes a heat exchanger of the core type within the shell for an LNG installation, where a deflector plate is used to divide the shell into a cooling zone containing the cores and a discharge zone.

Compendium of the invention

In one embodiment, a heat exchanger includes: (a) a defined internal volume within a shell; (b) a plurality of spaced apart cores arranged within the internal volume of the shell, and (c) splash suppression baffles, disposed within the internal volume to separate the plurality of spaced apart cores, in which each core is partially submerged in a fluid on the side of the liquid shell, in which the splash suppression baffles allow limited distribution of the fluid from the side of the liquid shell between each core, in which the splash suppression baffles can withstand cryogenic temperatures, in which splash suppression baffles can withstand and divert fluid flow from the side of the liquid shell between each core, in which the splash suppression baffles are located at the edge of each core, and in which the area between the splash suppression baffles is filled with packing material.

In another embodiment, a method is used to reduce the impact of movement in a heat exchanger, in which the heat exchanger includes a defined internal volume within a shell, in which the volume

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internal within the envelope includes a plurality of spaced apart cores, said method comprising: (a) installing splash suppression baffles within the internal volume of the inside of the envelope, in which the splash suppression baffles separate the plurality of cores in the internal volume, in which the splash suppression baffles are located at the edge of each core, and in which the area between the splash suppression baffles is filled with packing material; (b) partially immersing each core in a fluid on the side of the liquid shell, in which the splash suppression baffles allow a limited distribution of the fluid from the side of the liquid shell between each core; (c) introducing a fluid from the core side into each core; (d) cooling the fluid on the core side, thereby producing a cold current in each core; and (e) extract the cold current from each core.

Brief description of the drawings

The invention, together with additional advantages thereof, can be better understood by referring to the description that follows, taken together with the accompanying drawings, in which:

Figure 1 is a schematic view of a heat exchanger of the type of sheathed cores.

Figure 2 is a schematic view of a heat exchanger of the type of shell cores, an embodiment of splash suppression baffles.

Figure 3 is a schematic view of a heat exchanger of the type of shell cores, an embodiment of splash suppression baffles.

Figure 4 is a schematic view of a heat exchanger of the type of shell cores, the invention.

Figure 5 is a schematic view of a heat exchanger of the type of sheathed cores, horizontal baffles.

Fig. 6 is a schematic view of a heat exchanger of the type of shell cores, another embodiment of baffles.

Detailed description of the invention

Reference will now be made in detail to embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation, not as a limitation. It will be apparent to one skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention. For example, features illustrated or described as part of one embodiment can be used in another embodiment to produce yet another embodiment. Therefore, it is intended that the present invention cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

Referring to FIG. 1, a heat exchanger 10 is generally illustrated comprising a shell 12 and a plurality of spaced apart cores, that is, a first core 16, a second core 18 and a third core 20. The plurality of cores spaced from each other within the heat exchanger includes at least two cores. The envelope 12 is practically cylindrical, with an internal volume 14, and is defined by an upper side wall 22, a lower side wall 24 and a pair of end caps 26. For illustrative purposes, the heat exchanger is arranged horizontally; however, the heat exchanger may be positioned in any commercially operable manner, such as vertically, for example.

The first core 16, the second core 18, the third core 20 are disposed within the internal volume 14 of the shell and are partially submerged in the fluid on the side of the liquid shell. In one embodiment, the fluid on the side of the liquid shell is a vaporizing fluid, that is, a refrigerant. The fluid on the side of the liquid shell and the fluid on the side of the core flow in counter-current or in the manner that cross currents through each core.

Each of the plurality of spaced apart cores receives a fluid separated from the side of the core, which allows simultaneous indirect heat transfer between the fluid on the side of the liquid shell and the fluid on the side of the separated core.

A design principle behind the core heat exchanger in shell is the cross-exchange of fluid from the core side with respect to a fluid from the side of the liquid shell. The fluid on the side of the liquid shell is contained in a pressure vessel where compact heat exchanger welded heat exchanger cores are mounted and submerged in the fluid on the side of the liquid shell that is at or near its Boiling point. The liquid is propelled towards the bottom face of the heat exchanger, where it is brought into contact with hotter surfaces inside the core. Then the fluid on the side of the liquid shell transfers heat through the exchanger's core channels. Most of the heat transfer takes place from the latent heat of vaporization of the fluid from the side of the liquid shell. Side fluid

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The core is cooled or condensed as it passes through the opposite side of the channels inside the exchanger cores.

The thermal and hydraulic performance of the shell heat exchanger in shell is dependent on the level of the liquid in the exchanger. A driving force for the circulation of the fluid from the side of the liquid shell to the cores of the exchanger is the thermosiphon effect. The thermo-siphon effect is a passive fluid transfer phenomenon that results from natural convective thermal forces. As the vaporization of the fluid occurs, the fluid is heated and the density of the fluid decreases to become lighter. As it flows naturally upwards into the channels, new liquid is aspirated. This results in a natural circulation of the fluid from the side of the liquid envelope into the core channels, induced by the thermal gradient within the core. Not all the liquid in the channel is vaporized, and a mixture of liquid and vapors is transported upwards through the exchanger's core channels and expelled through the upper part of the core. Above the core, adequate space must be provided for the vapor and liquid to be released so that only steam leaves the head section of the core envelope side. The liquid that separates in the upper section of the exchanger is then recirculated towards the bottom of the container, where it is then vaporized inside the core. The driving force for the separation of the liquid and the gas in the upper section of the shell heat exchanger in shell is gravity.

The effect of thermo-siphon circulation in the core is enhanced or impaired by external hydraulic pressure (level differences) between the effective level of the liquid inside the core with respect to the level of the liquid outside the core. As the level of the liquid inside the shell decreases, the driving force for the transfer of the liquid into the core of the exchanger decreases, and the effective heat transfer is reduced. When the level of the liquid falls below the core, the circulation of the fluid from the side of the liquid shell stops due to the loss of the thermosiphon effect, which results in the loss of heat transfer. If the heat exchanger is operated with a liquid level greater than that of the core (flooded), the heat transferred is further impaired, since the steam produced in the core has to overcome the additional hydrostatic charge to escape the core. The most serious of the conditions is to have a lower liquid level than the exchanger cores, since this reduces heat transfer to near zero.

As explained above, the splashing of vaporizing fluid inside the heat exchangers can affect the stability and control of the exchanger. In addition, the cyclic nature of the movement will result in the cyclic behavior of the efficiency of heat transfer and, therefore, of the process conditions in the LNG liquefaction facility. These instabilities can lead to lower performance of the global installation and will lead to narrower operational envelopes.

The splash suppression baffles of the present invention reduce the impact of movement on the core heat exchanger in the shell. Splash suppression baffles are located within the internal volume of the shell to separate the plurality of spaced cores from each other. Each of the splash suppression baffles allows limited fluid distribution on the side of the liquid shell between each core. Splash suppression baffles can resist and divert fluid flow from the side of the liquid shell between each core.

Referring to FIG. 2, the splash suppression baffle 28 is a solid plate for providing reduced splashes of fluid from the side of the liquid shell within the heat exchanger 10. The solid baffle splash plate baffle 28 includes a opening at the bottom of the baffle to allow limited distribution of fluid from the side of the liquid shell between the cores. The height of the solid splash suppression plate deflector 28 depends on the extent of the anticipated movement. In one embodiment, the height of the solid motion suppression plate deflector is at or near the top of the core assembly. The placement and size of the baffle are critical due to the added movement in the lower part of the core and the resulting potential impact for the thermosiphon effect. The critical character for the size of the opening is to ensure that the thermosiphon effect is not impaired.

Referring to Figure 3, the splash suppression baffle 30 is a perforated plate located in the middle section of the core to dampen the effect of movement. In one embodiment, the perforated plate splash suppression baffle is a single plate. In another embodiment, the perforated plate splash suppression deflector is a double plate with compatible holes. With double plates, the vaporization liquid has to change the direction and further reduce the speed to pass through the second plate. A solid plate splash suppression baffle 28 is also represented between each core. This embodiment distributes the liquid more evenly and has a lower impact to the movement below the core and minimal impact on the thermosiphon.

Referring to Figure 4, the splash suppression baffles, 32, 34, 36, 38, 40 and 42, are located at the edge of each set of cores. Splash suppression baffles can be solid plates, perforated plates or a combination thereof. According to the invention, the area between each set of cores is filled with a packing material to dampen the movement of the flow.

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Referring to Figure 5, splash suppression baffles are installed between the cores horizontally to ensure that the upward drive is reduced. Splash suppression baffles can be solid plates, perforated plates or a combination thereof.

Referring to Figure 6, in order to reduce the movement in waves over the upper part of the core, which will lead to the dragging of potentially excessive liquid, due to the elevation of the liquid into the steam release space, deflectors of Splash suppression with angles or rounded at or near the top of the core assemblies to redirect the liquid away from the top of the core assemblies.

Any individual or combination splash suppression baffles described can be used to effectively and effectively reduce the effects of movement on the heat exchanger.

In addition to the installation of motion suppression baffle plates, certain types of packing material suitable for cryogenic services, such as structured stainless steel or random packing material, could be added to the empty spaces in the shell in order to suppress the movement. It is unlikely that structured or random packing alone will provide enough pressure drop to decrease the flow of moving fluid, but it can be used in conjunction with deflector plates to provide motion damping.

Very small wave movements can have a serious impact on the performance of the core heat exchanger in casing due to the normally large length of these exchangers. Narrow operational intervals result in movement sensitivity. Through careful consideration of the placement of the motion reduction baffles, the compact designs of the heat exchangers of the type of enveloped cores can be made to work in moving environments and alternatives such as shell and tube exchangers can be avoided , thus saving considerable costs.

Finally, it should be noted that the explanation of any reference is not an admission that it is a prior art to the present invention, especially any reference that may have a publication date after the priority date of this application. At the same time, each of the following claims is therefore incorporated into this detailed description or memory as a further embodiment of the present invention.

Although the systems and processes described herein have been explained in detail, it is to be understood that various changes, substitutions and alterations can be made without departing from the scope of the invention as defined in the following claims. Those skilled in the art may be able to study preferred embodiments and identify other ways of practicing the invention that are not exactly as described herein. It is the intention of the inventors that the variations and equivalents of the invention are within the scope of the claims, while the description, the compendium and the drawings are not to be used to limit the scope of the invention. The invention is specifically intended to be as broad as the following claims and their equivalents.

Claims (10)

5 10 fifteen twenty 25 30 35 40 Four. Five 1. A heat exchanger (10) comprising: (a) an internal volume defined within a shell (12); (b) a plurality of spaced apart cores (16, 18, 20) disposed within the internal volume of the shell (12), in which each core is partially submerged in a fluid on the side of the liquid shell, characterized in that (c) splash suppression baffles (28, 30) are arranged within the internal volume to separate the plurality of spaced apart cores (16, 18, 20), wherein the splash suppression baffles (28) allow limited distribution of fluid from the side of the liquid shell between each core (16, 18, 20), in which the splash suppression baffles (28) can withstand cryogenic temperatures, in which splash suppression baffles can withstand and divert fluid flow from the side of the liquid shell between each core (16, 18, 20), in which the splash suppression baffles (28, 30) are located at the edge of each core (16, 18, 20) and in which the area between the splash suppression baffles (28, 30) is filled with packing material. 2. The heat exchanger according to claim 1, wherein the splash suppression baffles (28) are installed between each core (16, 18, 20). 3. The heat exchanger according to claim 1, wherein the splash suppression baffles (28, 30) are installed between each core and in the middle section of the core. 4. The heat exchanger according to claim 1, wherein the splash suppression baffle (28, 30) is a solid plate, wherein the solid plate includes a passage near the bottom of the internal volume within of the envelope. 5. The heat exchanger according to claim 1, wherein the splash suppression baffle (28, 30) is a perforated plate. 6. The heat exchanger according to claim 1, wherein the splash suppression baffle (28, 30) is a double perforated plate. 7. The heat exchanger according to claim 1, wherein the fluid on the side of the liquid shell is a vaporizing fluid. 8. The heat exchanger according to claim 7, wherein the fluid on the side of the liquid shell is a refrigerant. 9. A method for reducing the impact of movement on a heat exchanger (10) according to any one of claims 1 to 8, wherein the heat exchanger (10) includes a defined internal volume within the shell (12) , in which the internal volume within the shell includes a plurality of spaced cores (16, 18, 20), said method comprising: to. install splash suppression baffles (28, 30) within the internal volume inside the shell, in which the splash suppression baffles separate the plurality of cores (16, 18, 20) into the internal volume, in the that the splash suppression baffles (28, 30) are located at the edge of each core (16, 18, 20), and in which the area between the splash suppression baffles (28, 30) is filled with material of packing; b. partially immerse each core (16, 18, 20) in a fluid on the side of the liquid shell, in which the splash suppression baffles (28, 30) allow limited distribution of fluid from the side of the liquid shell between each core (16, 18, 20); C. introduce a fluid from the core side into each core (16, 18, 20); d. cooling the fluid on the core side to produce a cold current in each core (16, 18, 20); Y and. extract the cold current from each core (16, 18, 20). 10. The method according to claim 9, wherein the splash suppression baffles (28, 30) can withstand cryogenic temperatures.