MOVING FILM, DIRECT CONTACT, LIQUID TO LIQUID HEAT TRANSFER PROCESS

Abstract

A heat transfer process focused for heating or cooling an aggressive liquid employing direct contact through an immiscible fluid film of differing density. The fluid film adheres to a solid wall heat transfer surface purveying both transference of heat therein as well as isolation protection of the heat transfer surface from damage, coating or scaling from the adjacent aggressive liquid.

Claims

1. A method for transferring heat between a liquid and a fluid comprising: partially submerging the lower end of at least one tube within a liquid, wherein the upper end of said at least one tube is above said liquid; allowing a fluid to access the upper end of said at least one tube, wherein said fluid is immiscible with said liquid, and wherein said fluid is a different temperature than said liquid, thereby directly transferring heat between said fluid and said liquid; and as said fluid leaves said lower end of said at least one tube and rises, said fluid separates said at least one tube from said liquid.

2. The method of claim 1, wherein said fluid is heated and, as said fluid passes through said at least one tube, said fluid heats said at least one tube in passing and, as said fluid leaves said lower end of said at least one tube, said fluid maintains contact with said at least one tube, thereby separating said liquid from said at least one tube.

3. The method of claim 1, wherein said separation afforded by said fluid between said liquid and said at least one tube prevents damage to, or coating of, said at least one tube from said liquid or constituents entrained therein.

4. The method of claim 1, wherein said at least one tube is preferentially wetted by said fluid in deference to said liquid thereby enhancing adherence of said fluid to said at least one tube and purveying improved heat transfer from said at least one tube through said fluid to said liquid.

5. The method of claim 1, wherein said at least one tube is preferentially wetted by said fluid in deference to said liquid thereby enhancing adherence of said fluid to said at least one tube and providing improved protection from damage to, or coating of, said at least one tube from said liquid or constituents entrained therein.

6. The method of claim 1, wherein said fluid is cooled below the temperature of said liquid and said fluid cools said at least one tube when passing through said at least one tube.

7. A device for transferring heat between a fluid and a liquid comprising: a container containing a liquid; one or more tubes configured so all upper ends of said one or more tubes are above said liquid and all lower ends of said one or more tubes are submerged in said liquid; a fluid positioned to be accessible to said upper ends of said one or more tubes, said fluid being immiscible with said liquid and having a different temperature and density than said liquid; wherein as said fluid accesses said one or more tubes, heat is transferred between said fluid and said liquid; wherein said differing density purveys relative motion between said fluid and said liquid; and wherein, after said fluid passes through said lower ends of said one or more tubes, said fluid affords separation between said one or more tubes and said liquid.

8. The device of claim 7 wherein said fluid is heated and, as said fluid accesses said upper ends of said one or more tubes and passes through said one or more tubes, said fluid heats said one or more tubes and said one or more tubes heat said liquid.

9. The device of claim 7 wherein said separation provides protection from damage to, or coating of, said one or more tubes from said liquid or constituents entrained therein.

10. The device of claim 7 wherein said one or more tubes is preferentially wetted by said fluid in deference to said liquid, thereby enhancing adherence of said fluid to said one or more tubes and improving heat transfer between said one or more tubes and said liquid through said fluid.

11. The device of claim 7 wherein said one or more tubes is preferentially wetted by said fluid in deference to said liquid thereby enhancing adherence of said fluid to said one or more tubes, thereby improving protection from damage to, or coating of, said one or more tubes from said liquid or constituents entrained therein.

12. The device of claim 7 wherein said fluid is cooled and, as said fluid accesses the upper end of said one or more tubes and passes through said one or more tubes, said fluid cools said one or more tubes and said one or more tubes cools said liquid.

13. The device of claim 7 wherein said immiscibility and said differing density affords separation of said fluid and said liquid subsequent to heat transfer.

14. A heat transfer system comprising: a. a first container containing a liquid, said first container having at least one liquid ingress, at least one liquid egress and at least one fluid egress; b. at least one vertical tube with a first end positioned within said liquid and a second end positioned to receive a fluid from a second container, wherein said fluid is immiscible with said liquid and wherein said fluid and said liquid are of differing density; c. wherein as said fluid passes from said second container through said tube, heat is transferred between said fluid and said liquid; d. wherein said differing density purveys relative motion between said fluid and said liquid; and e. wherein upon exiting said tube, said fluid affords separation between said tube's external surface and said liquid.

15. The device of claim 14 wherein said fluid is conveyed into said second container, wherein said second container is elevated relative to said first container and wherein said liquid is cooler and denser than said fluid, as said fluid passes from said second container downward through said tube, said fluid heats said tube, thereby cooling said fluid, as said fluid exits said first end of said tube into said liquid, said fluid, due to its lower density than said liquid rises upward while adhering in a film-like sheath to said tube's external surface, said tube thereby transferring heat to said fluid as it rises which, in turn, transfers heat to said liquid, wherein movement of said liquid between said at least one liquid ingress and said at least one liquid egress creates movement of said liquid in said first container and, therefore, across said sheath, thereby imbuing heat transfer from said sheath to said liquid; and wherein, after said fluid rises above said liquid, said fluid exits said first container through said at least one fluid egress.

16. The device of claim 14 wherein said fluid is conveyed into said second container, wherein said second container is elevated relative to said first container and wherein said liquid is warmer and denser than said fluid, as said fluid passes from said second container downward through said tube, said fluid cools said tube, thereby warming said fluid, as said fluid exits said first end of said tube into said liquid, said fluid, due to its lower density than said liquid rises upward while adhering in a film-like sheath to said tube's external surface, said tube thereby extracting heat from said fluid as it rises which, in turn, extracts heat from said liquid, wherein movement of said liquid between said at least one liquid ingress and said at least one liquid egress creates movement of said liquid in said first container and, therefore, across said sheath, thereby extracting heat from said sheath to said liquid; and wherein, after said fluid rises above said liquid, said fluid exits said first container through said at least one fluid egress.

17. The device of claim 14 wherein said fluid is conveyed into said second container, wherein said second container is lower relative to said first container and wherein said liquid is cooler and denser than said fluid, as said fluid passes from said second container upward through said tube, said fluid heats said tube, thereby cooling said fluid, as said fluid exits said first end of said tube into said liquid, said fluid, due to its higher density than said liquid moves downward while adhering in a film-like sheath to said tube's external surface, said tube thereby transferring heat to said fluid as it falls which, in turn, transfers heat to said liquid, wherein movement of said liquid between said at least one liquid ingress and said at least one liquid egress creates movement of said liquid in said first container and, therefore, across said sheath, thereby transferring heat from said sheath to said liquid; and wherein, after said fluid falls below said liquid, said fluid exits said first container through said at least one fluid egress.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0055] For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0056] FIG. 1 is a schematic diagram of one embodiment the subject process wherein a lower density immiscible heat transfer fluid with no solubility for scaling solutes is employed to transfer heat with a higher density aggressive liquid;

[0057] FIG. 2 is a schematic diagram of one embodiment the subject process wherein a higher density immiscible heat transfer fluid with no solubility for scaling solutes, is employed to transfer heat with a lower density aggressive liquid;

[0058] FIG. 3 is a schematic diagram of a device wherein a lower density immiscible fluid, with no solubility for scaling solutes, is employed to transfer heat with a higher density aggressive liquid; and

[0059] FIG. 4 is a schematic diagram of a device wherein a lower density immiscible fluid, with no solubility for scaling solutes, is employed to transfer heat with a higher density aggressive liquid.

DETAILED DESCRIPTION OF THE DRAWINGS

[0060] The making and use of the process and example embodiments of the device are discussed in detail below. It should be appreciated, however, that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the invention, and do not limit the scope of the invention. The present invention will be described with respect to various embodiments in a specific context, namely as a device and process for heating an aggressive liquid by submersion of a heated surface in the aggressive liquid wherein the heated surface is protected from the aggressive liquid by a film of a separate and immiscible fluid coating the heated surface. In some embodiments, process and device employ a protective, immiscible fluid of lower density than the aggressive liquid thereby impelling buoyant rising carriage and separation of the immiscible fluid from the aggressive liquid. The invention may also be applied wherein the immiscible fluid is denser than the aggressive liquid thereby impelling a sinking carriage and separation of the immiscible fluid from the aggressive liquid. The process may be further enhanced through the employ of an immiscible fluid having low solubility for scale forming solutes. In addition, the immiscible fluid and aggressive liquid may present relative surface tension characteristics affording preferential adherence of the fluid to the heat transfer surfaces.

[0061] As should be obvious to those skilled in the art that the processes and device implementations described herein may also be readily applied to applications wherein cooling or cyclical heating or cooling functions of the aggressive liquid are sought. Wherein with cooling applications the simple shift to cooler immiscible fluid addressing a warmer aggressive liquid obviously pertains. The processes and devices of the subject invention may also be readily applied in multiple and diverse other applications wherein the invention addresses heating or cooling of many types of liquids, not being limited to aggressive liquids.

[0062] There are many features of the heat transfer process and device implementations disclosed herein, of which one, a plurality, or all features or steps may be employed in any particular implementation.

[0063] In the following description, reference is made to the accompanying-figures which form a part hereof, and which show by way of illustration possible implementations. It should be understood that other implementations may be utilized, and structural, as well as procedural, changes may be made without departing from the scope of this disclosure. As a matter of convenience, various components will be described using exemplary materials, sizes, shapes, dimensions, and the like. However, the invention is not limited to the stated implementations and examples and other configurations are possible and within the teachings of the present disclosure.

[0064] A heat transfer process and device is described herein with respect to implementations in specific contexts. Furthermore, it should be appreciated by those skilled in the art that the conception and specific implementations disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present disclosure. It should be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of this disclosure.

[0065] Various embodiments of the invention employ an immiscible fluid with low solubility for scale forming solutes to both transfer heat into an element submerged in an aggressive liquid and to coat and protect the element from being damaged or impaired by the aggressive liquid. Further, the immiscible fluid is motivated for travel within and collection without the aggressive liquid because of the differing density between the immiscible fluid and the aggressive liquid. Additionally, in one embodiment, the immiscible fluid provides coated protection of the heated element as a consequence of preferential wetting of the element by the immiscible fluid in deference to the aggressive liquid.

[0066] In a general process description of one embodiment, a warmer, lower density, immiscible fluid with no solubility for scale forming solutes is conveyed into the upper end of a heat exchanger tube, which is vertically submerged within but extending upwards without an aggressive liquid. The liquid is of a higher density than the immiscible fluid. The aggressive liquid would normally damage or impair the materials or heat transfer capability of the heat transfer tube.

[0067] The heated immiscible fluid transfers heat into the heat exchanger tube wall material as the fluid conveys vertically downward within the tube, thereby cooling the immiscible fluid concurrent with heating the tube.

[0068] The lower end of the tube is open to the surrounding cooler and higher density aggressive liquid. The cooled immiscible fluid exits the lower open end of the tube into direct contact with the surrounding aggressive liquid. The lower density of the immiscible fluid relative to the aggressive liquid buoys the immiscible fluid upward as it exits the lower end of the heat exchanger tube.

[0069] Preferential wetting of the heat exchanger tube by the immiscible fluid purveys adherence of the rising immiscible fluid as a film-like sheath about the outside surface of the heat exchanger tube, thereby physically separating the aggressive liquid from the heat exchanger tube and protecting the tube accordingly.

[0070] As the immiscible fluid sheath rises along the heat exchanger tube external wall, heat sourced from the heated downward flowing immiscible liquid within the tube transfers into the tube wall. The heated tube wall in turn heats the external immiscible fluid rising in the film-like sheath about the tube. The heated immiscible fluid comprising the rising sheath, in turn, heats the surrounding aggressive liquid by direct contact thereof.

[0071] The immiscible fluid sheath rises to the top surface of the aggressive liquid where it separates from adherence with the tube forming a layer of immiscible fluid on the surface of the aggressive liquid. The warmed aggressive liquid egresses the process for external use from below the immiscible fluid layer. The cool immiscible fluid egresses the process from above the aggressive liquid for reheat and continuation of the heat exchange process.

[0072] With reference now to FIG. 1, one embodiment of the present invention employs a vertically oriented, thermally conductive tube 100 with one end 102 submerged within an aggressive liquid 104 and the other end 106 extending without the aggressive liquid 104.

[0073] A fluid 108 ingresses the upper tubing end 106. Fluid 108 is hotter than, immiscible with, and of lower density than liquid 104. Further, fluid 108, in deference to liquid 104, preferentially wets the surface material of tube 100.

[0074] Fluid 108 conveys downward in tube 100 heating the tubing walls of tube 100 as fluid 108 conveys downward therein. Fluid 108 egresses the lower opening 102 of tubing tube 100, entering into the environs of liquid 104. The higher density of liquid 104 buoys fluid 108 upward upon egressing the tube end 102.

[0075] The preferential wetting of the external wall of the tube 100 by the fluid 108 rather than the surrounding liquid 104 incites adherence of fluid 108 to the external wall of tube 100 as fluid 108 buoys upward by the higher density of surrounding liquid 104. The adherence of the rising fluid 108 to the external wall of the tube 100 forms a rising sheath 110 about tube 100. Sheath 110 protects tube 100 from detrimental contact with liquid 104. The tubing 100 is heated by internal conveyance of the heated fluid 108. The heated wall of tube 100 heats the rising sheath 110 which in turn, by direct contact, heats the surrounding liquid 104

[0076] Upon rising to the upper surface of liquid 104, fluid sheath 110 degenerates and fluid 108 disperses as an immiscible floating layer 112 above the liquid 104.

[0077] FIG. 2 depicts a similar, albeit mirrored, process to FIG. 1. One embodiment of the present invention employs a vertically oriented, thermally conductive tube 101 with one end 103 rising into an aggressive liquid 105 and the other end 107 extending through a sealing wall 115 to an isolated region below liquid 105 and sealing wall 115.

[0078] A fluid 109 ingresses the lower tubing end 107. Fluid 109 is hotter than, immiscible with, and of higher density than liquid 105. Further, fluid 109, in deference to liquid 105, preferentially wets the surface material of tube 101.

[0079] Fluid 109 conveys upward in tube 101 heating the tubing walls of tube 101 as fluid 109 conveys upward therein. Fluid 109 egresses the upper opening 103 of tubing tube 101, entering into the environs of liquid 105. The higher density of fluid 109 in the environs of liquid 105 incites a sinking motion of fluid 109 upon egressing the tube end 103.

[0080] The preferential wetting of the external wall of the tube 101 by the fluid 109 rather than the surrounding liquid 105 incites adherence of fluid 109 to the external wall of tube 101 as fluid 109 sinks downward in the lower density of the surrounding liquid 105.

[0081] The adherence of the sinking fluid 109 to the external wall of the tube 101 forms a falling sheath 111 about tube 101. Sheath 111 protects tube 101 from detrimental contact with liquid 105. The tubing 101 is heated by internal conveyance of the heated fluid 109. The heated tube 101 heats the falling sheath 111, which in turn, by direct contact, heats the surrounding liquid 105. Upon sinking to the bottom of liquid 105, fluid sheath 111 degenerates and fluid 109 disperses as an immiscible layer 113 below the liquid 105.

[0082] FIG. 3 depicts a similar situation to FIG. 1, albeit inclusive of a physical vessel with conveyance features and associated ingress and egress flows. This embodiment of the present invention so illustrated employs an essentially vertical vessel 214 with an ingress 218 and two egress conveyance ports 216 and 220 wherein 216 is located at a higher elevation in vessel 214 than 220. A vertically oriented, thermally conductive tube 200 has one end 202 submerged within an aggressive liquid 204 and the other end 206 extending without the aggressive liquid 204. Aggressive liquid 204 has ingress to vessel 214 by means of conveyance port 218.

[0083] A fluid 208 ingresses the upper tubing end 206. Fluid 208 is hotter than, immiscible with, and of lower density than liquid 204. Further, fluid 208, in deference to liquid 204, preferentially wets the surface material of tube 200. Fluid 208 conveys downward in tube 200 heating the tubing walls of tube 200 as fluid 208 conveys downward therein. Fluid 208 egresses the lower opening 202 of tubing tube 200, entering into the environs of liquid 204. The higher density of liquid 204 buoys fluid 208 upward upon egressing the tube end 202.

[0084] The preferential wetting of the external wall of the tube 200 by the fluid 208 rather than the surrounding liquid 204 incites adherence of fluid 208 to the external wall of tube 200 as fluid 208 buoys upward by the higher density of surrounding liquid 204.

[0085] The adherence of the rising fluid 208 to the external wall of the tube 200 forms a rising sheath 210 about tube 200. Sheath 210 protects tube 200 from detrimental contact with liquid 204.

[0086] The tubing 200 is heated by internal conveyance of the heated fluid 208. The heated wall of tube 200 heats the rising sheath 210 which in turn, by direct contact, heats the surrounding liquid 204. Upon rising to the upper surface of liquid 204, fluid sheath 210 degenerates and fluid 208 disperses as an immiscible floating layer 212 above the liquid 204. Conveyance port 220 affords egress of the now warmed liquid 204 from the vessel 214 for external process use. The cooled fluid 208 egresses the layer 212 and the vessel 214 by conveyance port 216.

[0087] With reference now to a preferred embodiment illustrated in FIG. 4, in addition to the process embodiment presented by FIG. 3, this embodiment employs a multitude of heat exchanger tubes communicating with an overhead vessel. Further, the aggressive liquid containment vessel employs a method to support fluid levels therein.

[0088] This preferred embodiment employs an essentially vertical vessel 314 with an ingress 318 and two egress conveyance ports 316 and 320 wherein 316 is located at a higher elevation in vessel 314 than 320. An aggressive liquid 304 purveys ingress to vessel 314 by means of a conveyance port 318. A plurality of vertically oriented, thermally conductive tubes 300, are positioned having their lower ends 302 submerged within aggressive liquid 304, and the other upper ends 306 extending without the aggressive liquid 304 and into, and in hydraulic communication with, an overhead fluid containment vessel 322.

[0089] Ingress to vessel 322 purveys by conveyance 324 and egress from vessel 322 by the open tube ends 306. A fluid 308 ingresses vessel 322 through ingress conveyance port 324. Fluid 308 is hotter than, immiscible with, and of lower density than aggressive liquid 304. Further, fluid 308, in deference to liquid 304, preferentially wets the surface material of tube 300.

[0090] Hot fluid 308 egresses vessel 322 by entry into the upper open ends 306 of the tubes 300. Fluid 308 conveys downward in tubes 300, heating the tubing walls of tubes 300 as fluid 308 conveys downward therein. Fluid 308 egresses the lower openings 302 of tubes 300 and enters the environs of liquid 304. The higher density of liquid 304 buoys fluid 308 upward upon egression from the tube ends 302.

[0091] The preferential wetting of the external wall of the tubes 300 by the fluid 308 rather than the surrounding liquid 304 incites adherence of fluid 308 to the external walls of tubes 300 as fluid 308 buoys upward by the higher density of surrounding liquid 304. The adherence of the rising fluid 308 to the external wall of the tubes 300 forms a rising sheath 310 about tubes 300. Sheath 310 protects tubes 300 from detrimental contact with liquid 304.

[0092] The internal conveyance of the heated fluid 308 heats the walls of the tubes 300. In turn, the heated walls of tubes 300 heat the rising sheaths 310 which, by direct contact, heat the surrounding liquid 304

[0093] Upon rising to the upper surface of liquid 304, fluid sheaths 310 degenerate and fluid 308 disperses as an immiscible floating layer 312 above the liquid 304.

[0094] Overflow weir 328 affords egress of the now warmed liquid 304 from the vessel 314 into a fluid leveling balance line 332. Fluid leveling balance line 332 and overflow weir 328 provide fluid level control within vessel 314.

[0095] In one embodiment, vessel 314 is cylindrical wherein the overflow weir 328 presents an annular collection region around the internal perimeter of vessel 314. Ingress conveyance 318 disperses the cold, aggressive liquid 304 central to and in the lower region of vessel 314. In combination with the annular overflow weir 328, this configuration conveys an upward and radially outward flow of the aggressive liquid 304 in the vessel 314 and about the tubes 300; imbuing both thermal countercurrent up-flow and radial fluid cross flow, provisioning superior thermal transfer performance.

[0096] The now warmed liquid 304 egresses, for external process use, from the fluid leveling balance line 332 at egress conveyance 320.

[0097] Cooled fluid 308 egresses the floating layer 312 and the vessel 314 by conveyance port 316. After being externally and independently reheated, fluid 308 returns to ingress port 324 for continuation of the process.

[0098] The simple and novel features of the process and devices described herein purvey heat transfer with an aggressive liquid through the employ of an immiscible fluid to both carry heat to a heat transfer surface and to protect that surface from damaging effects of the aggressive liquid.

[0099] A further novel feature of the subject process and device is the employ of an immiscible fluid of differing density than the aggressive fluid, facilitating natural and simple movement and separation of the immiscible fluid and aggressive liquid.

[0100] Another novel feature of the subject art is the preference of the immiscible fluid rather than the aggressive liquid to wet the heat transfer surfaces; thereby purveying tenacious adherence of the immiscible fluid to the heat transfer surfaces, effectively isolating and reliably protecting these surfaces from the aggressive liquid.

[0101] Another novel effect is provision of direct contact, reliable and efficient heat transfer within scaling liquids wherein, were it not for the adherence and protection facilitated by the immiscible fluid unto heat transfer surfaces, scaling or fouling of said surfaces would impede heat transfer.

[0102] Another novel effect is provision of direct contact, reliable and efficient heat transfer within scaling liquids without the necessity of scale inhibiting chemicals addition.

[0103] Another novel effect is provision of direct contact, reliable and efficient heat transfer within scaling liquids without the requirement for mechanical scrapping or abrading to remove heat transfer inhibiting scale or fouling.

[0104] Another novel effect is provision of direct contact, reliable and efficient heat transfer within corrosive liquids without the requirement for chemical corrosion inhibitors to protect heat transfer surfaces.

[0105] Another novel effect is provision of direct contact, reliable and efficient heat transfer within corrosive liquids without the requirement for exotic or expensive, corrosion resistant, heat transfer materials.

[0106] Another novel effect is provision of direct contact, reliable and efficient heat transfer within scaling or corrosive liquids without the requirement for blowdown or dilution to reduce scaling or corrosion effects.

[0107] Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. Finally, in the foregoing discussion and in the claims, the terms including and comprising are used in an open-ended fashion, and thus should be interpreted to mean including, but not limited to . . . .