WO2008011666A1 - System and method of heat transfer - Google Patents

System and method of heat transfer Download PDF

Info

Publication number
WO2008011666A1
WO2008011666A1 PCT/AU2007/001024 AU2007001024W WO2008011666A1 WO 2008011666 A1 WO2008011666 A1 WO 2008011666A1 AU 2007001024 W AU2007001024 W AU 2007001024W WO 2008011666 A1 WO2008011666 A1 WO 2008011666A1
Authority
WO
WIPO (PCT)
Prior art keywords
liquid
stream
cooling fluid
heat exchanger
heat
Prior art date
Application number
PCT/AU2007/001024
Other languages
French (fr)
Inventor
Kenneth William Patterson Drysdale
Original Assignee
Drysdale Kenneth William Patte
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Drysdale Kenneth William Patte filed Critical Drysdale Kenneth William Patte
Publication of WO2008011666A1 publication Critical patent/WO2008011666A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F23/00—Features relating to the use of intermediate heat-exchange materials, e.g. selection of compositions
    • F28F23/02—Arrangements for obtaining or maintaining same in a liquid state

Definitions

  • the present invention relates to systems and methods for heat exchange, and in particular, but not exclusively, to a system and method for transferring heat between a vapour stream and a cooling liquid.
  • a method of transferring heat from a first vapour stream to a cooling fluid including the steps of: I, transferring heat from the first vapour stream to a liquid stream; Ii. transferring heat from the liquid stream to the cooling fluid.
  • the method includes circulating the liquid stream around a closed circuit.
  • the liquid is an oil.
  • the liquid is a mixture of water and ethylene glycol.
  • the cooling fluid is a second vapour stream.
  • the method includes controlling the rate of flow of the liquid stream to ensure that the heat transferred from the first vapour stream to the liquid stream does not boll the liquid.
  • a system for transferring heat from a first vapour stream to a cooling fluid including a first heat exchanger for transferring heat from the first vapour stream to a liquid in a closed circuit, a second heat exchanger for transferring heat from the liquid to the cooling fluid, and means for circulating the liquid around the closed circuit.
  • the liquid is an oil.
  • the liquid is a mixture of water and ethylene glycol.
  • the temperature of the liquid remains lower than a boiling temperature of the liquid when the liquid is within the first heat exchanger.
  • the cooling fluid is a second vapour stream.
  • the system includes sensor means for sensing a temperature of the liquid exiting the first heat exchanger, and control means adapted to control a rate of flow of the liquid stream to ensure that the liquid does not boil within the first heat exchanger.
  • a power generation system including a first heat exchanger for transferring heat from a first vapour stream to a liquid in a closed circuit, means for circulating the liquid around the closed circuit, and a second heat exchanger for transferring heat from the liquid to a cooling fluid, wherein the second heat exchanger is provided with at least one thermoelectric generator which has a hot junction in thermal contact with the liquid and a cold junction in thermal contact with the cooling fluid.
  • a system for transferring heat from a first vapour stream to a cooling fluid is substantially as herein described with reference to the accompanying drawings.
  • Figure 1 is a schematic diagram of a system for transferring heat from a vapour stream to a cooling fluid.
  • Figure Z is a schematic cross-section of a heat exchanger suitable for use with the system of Figure 1.
  • vapour Is used to mean a fluid in a substantially gaseous phase, whether saturated or not.
  • cooling fluid includes any suitable fluid, whether in a liquid or vapour state.
  • a system for transferring heat from a vapour stream 1 to a cooling fluid 2 is generally referenced 100.
  • the vapour stream may be a stream of flue gas from a commercial boiler.
  • the system 100 includes a first heat exchanger 3 which transfers heat from the vapour stream 1 to a liquid stream 4 which flows around a closed eirouit 5.
  • the liquid stream 4 is preferably a thermal oil having a relatively high boiling point and/or density and/or specific heat capacity, in an alternative embodiment the liquid may be a suitable water based liquid, for example a mixture of 65% water and 35% ethylene glycol additive such as Dowcal 10, manufactured by the Dow Chemical Company.
  • the system 100 includes a second heat exchanger 6 for transferring heat from the liquid stream 4 to the cooling fluid 2.
  • the cooling fluid 2 may be a liquid which is heated or boiled by the heat from the liquid stream 4.
  • a proportion of the heat transferred into the second fluid stream may be converted to useful energy by a suitable conversion means such as a turbine,
  • a pump 7 or some other suitable means is provided to pump the liquid around the closed circuit s.
  • the liquid stream 4 remains in a substantially liquid form throughout the dosed circuit 5, and in particular within the first heat exchanger 3.
  • the temperature of the liquid leaving the first heat exchanger 3 may be monitored by suitable sensor means (not shown), and the flow rate of the liquid stream 4 may be varied by a control means (not shown) as necessary to ensure that a sufficient amount of heat is removed from the first vapour stream 1 without boiling the liquid in the first heat exchanger 3, In one embodiment the flow rate may be varied by varying the speed of the pump 7.
  • the rate of heat transfer achieved by the first heat exchanger 3 may be decreased, which may in turn result in a rise in back pressure of the vapour stream 1.
  • a heat exchanger Is generally referenced 200.
  • the heat exchanger 200 is suitable for use as at least the second heat exchanger 6 in the system described above.
  • the heat exchanger 200 is based on a plate heat exchanger design, and is provided with one or more thermoelectric generator means S such as are known to those skilled In the art.
  • a cold junction 9 of each thermoelectric generator means 8 is in thermal contact with the cooling fluid 2 and a hot junction 10 of each thermoelectric generator means 8 is in thermal contact with the liquid stream 4.
  • the thermoelectric generator means 8 produce electric power from the temperature difference between their hot and cold junctions.
  • the liquid stream 4 and the cooling fluid 2 are separated by a partition 11 , as is common in plate heat exchanger designs.
  • the cooling fluid 2 may be a vapour stream, but is more preferably a liquid, for example water.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Motor Or Generator Cooling System (AREA)

Abstract

A method of transferring heat from a first vapour stream (1) to a cooling fluid (2) includes the steps of: I) transferring heat from the first vapour stream (1) to a liquid stream (4); II) transferring heat from the liquid stream (4) to the cooling fluid (2), The heat transfer is preferably performed by a heat exchanger (200) which is provided with at least one thermoelectric generator (8) which has a hot junction (10) in thermal contact with the liquid (4) and a cold junction (9) in thermal contact with the cooling fluid (2).

Description

SYSTEMAND METHOD OFHEATTRANSFER
Field of the Invention
5.
The present invention relates to systems and methods for heat exchange, and in particular, but not exclusively, to a system and method for transferring heat between a vapour stream and a cooling liquid. 0 Background to the Invention
In most thermal power generation systems it is necessary to transfer heat between a vapour stream and a cooling fluid. If the heat is not transferred at a sufficiently high rate then the pressure of the vapour stream may not be reduced sufficiently and an increase in back5 pressure may result. This problem may manifest in particular in systems where heat is being transferred from the vapour stream to a second vapour stream,
Object of the Invention
It is an object of a preferred embodiment of the invention to provide a system for0 transferring heat from a first vapour stream to a cooling fluid and/or a method of transferring heat from a first vapour stream to a cooling fluid which will overcome or ameliorate problems with such systems and/or methods at present, or at least one which will provide the public with a useful choice,
Other objects of the present invention may become apparent from the following description, which is given byway of example only,
Summary of the Invention
According to a first aspect of the present invention there is provided a method of transferring heat from a first vapour stream to a cooling fluid including the steps of: I, transferring heat from the first vapour stream to a liquid stream; Ii. transferring heat from the liquid stream to the cooling fluid.
Preferably, the method includes circulating the liquid stream around a closed circuit. Preferably, the liquid is an oil.
Preferably, the liquid is a mixture of water and ethylene glycol.
Preferably, the cooling fluid is a second vapour stream.
Preferably, the method includes controlling the rate of flow of the liquid stream to ensure that the heat transferred from the first vapour stream to the liquid stream does not boll the liquid.
According to a second aspect of the present invention there is provided a system for transferring heat from a first vapour stream to a cooling fluid, the system including a first heat exchanger for transferring heat from the first vapour stream to a liquid in a closed circuit, a second heat exchanger for transferring heat from the liquid to the cooling fluid, and means for circulating the liquid around the closed circuit.
Preferably, the liquid is an oil.
Preferably, the liquid is a mixture of water and ethylene glycol.
Preferably, the temperature of the liquid remains lower than a boiling temperature of the liquid when the liquid is within the first heat exchanger.
Preferably, the cooling fluid is a second vapour stream.
Preferably, the system includes sensor means for sensing a temperature of the liquid exiting the first heat exchanger, and control means adapted to control a rate of flow of the liquid stream to ensure that the liquid does not boil within the first heat exchanger.
According to a third aspect of the present invention there is provided a power generation system including a first heat exchanger for transferring heat from a first vapour stream to a liquid in a closed circuit, means for circulating the liquid around the closed circuit, and a second heat exchanger for transferring heat from the liquid to a cooling fluid, wherein the second heat exchanger is provided with at least one thermoelectric generator which has a hot junction in thermal contact with the liquid and a cold junction in thermal contact with the cooling fluid.
According to a further aspect of the present invention a system for transferring heat from a first vapour stream to a cooling fluid is substantially as herein described with reference to the accompanying drawings.
Further aspects of the invention, which should be considered in all its novel aspects, will become apparent from the following description given by way of example of possible embodiments of the invention.
Brief Description of the Drawings
Figure 1 : is a schematic diagram of a system for transferring heat from a vapour stream to a cooling fluid.
Figure Z: is a schematic cross-section of a heat exchanger suitable for use with the system of Figure 1.
Best Mode for Performing the invention
Within the following description the term "vapour" Is used to mean a fluid in a substantially gaseous phase, whether saturated or not.
The term "cooling fluid" includes any suitable fluid, whether in a liquid or vapour state.
Referring first to Figure 1 , a system for transferring heat from a vapour stream 1 to a cooling fluid 2 according to one embodiment of the present invention is generally referenced 100. In one embodiment the vapour stream may be a stream of flue gas from a commercial boiler.
The system 100 includes a first heat exchanger 3 which transfers heat from the vapour stream 1 to a liquid stream 4 which flows around a closed eirouit 5. The liquid stream 4 is preferably a thermal oil having a relatively high boiling point and/or density and/or specific heat capacity, in an alternative embodiment the liquid may be a suitable water based liquid, for example a mixture of 65% water and 35% ethylene glycol additive such as Dowcal 10, manufactured by the Dow Chemical Company.
The system 100 includes a second heat exchanger 6 for transferring heat from the liquid stream 4 to the cooling fluid 2. In one embodiment the cooling fluid 2 may be a liquid which is heated or boiled by the heat from the liquid stream 4. In a particularly preferred embodiment a proportion of the heat transferred into the second fluid stream may be converted to useful energy by a suitable conversion means such as a turbine,
A pump 7 or some other suitable means is provided to pump the liquid around the closed circuit s.
In a preferred embodiment the liquid stream 4 remains in a substantially liquid form throughout the dosed circuit 5, and in particular within the first heat exchanger 3. In one embodiment the temperature of the liquid leaving the first heat exchanger 3 may be monitored by suitable sensor means (not shown), and the flow rate of the liquid stream 4 may be varied by a control means (not shown) as necessary to ensure that a sufficient amount of heat is removed from the first vapour stream 1 without boiling the liquid in the first heat exchanger 3, In one embodiment the flow rate may be varied by varying the speed of the pump 7.
If the liquid stream 4 is allowed to boil inside the first heat exchanger 3 then the rate of heat transfer achieved by the first heat exchanger 3 may be decreased, which may in turn result in a rise in back pressure of the vapour stream 1.
Referring next to Figure 2, a heat exchanger Is generally referenced 200. The heat exchanger 200 is suitable for use as at least the second heat exchanger 6 in the system described above.
The heat exchanger 200 is based on a plate heat exchanger design, and is provided with one or more thermoelectric generator means S such as are known to those skilled In the art. A cold junction 9 of each thermoelectric generator means 8 is in thermal contact with the cooling fluid 2 and a hot junction 10 of each thermoelectric generator means 8 is in thermal contact with the liquid stream 4. The thermoelectric generator means 8 produce electric power from the temperature difference between their hot and cold junctions. The liquid stream 4 and the cooling fluid 2 are separated by a partition 11 , as is common in plate heat exchanger designs.
In this embodiment the cooling fluid 2 may be a vapour stream, but is more preferably a liquid, for example water.
Where in the foregoing description, reference has been made to specific components or integers of the invention having known equivalents, then such equivalents are herein incorporated as if individually set forth.
Although this invention has been described by way of example and with reference to possible embodiments thereof, it is to be understood that modifications or improvements may be made thereto without departing from the spirit or scope of the claims.

Claims

ClAlMS
1. A method of transferring heat from a first vapour stream to a cooling fluid, the method including the steps of: I, transferring heat from the first vapour stream to a liquid stream;
II, transferring heat from the liquid stream to the cooling fluid.
2. The method of claim 1 wherein the liquid stream is circulated around a closed circuit.
3. The method of claim 1 or 2 wherein the liquid is an oil.
4. The method of claim 1 or 2 wherein the liquid is a mixture of water and ethylene glycol.
5. The method of claim 1 , 2, 3 or 4 wherein the cooling fluid is a second vapour stream.
6. The method of any one of claims 1 to 5 including controlling the rate of flow of the liquid stream to ensure that the heat transferred from the first vapour stream to the liquid stream does not boil the liquid.
7. A system for transferring heat from a first vapour stream to a cooling fluid, the system including a first heat exchanger for transferring heat from the first vapour stream to a liquid in a closed circuit, a second heat exchanger for transferring heat from the liquid to the cooling fluid, and means for circulating the liquid around the closed circuit.
8. The system of claim 7 wherein the liquid is an oil.
9. The system of claim 7 wherein the liquid is a mixture of water and ethylene glycol.
10. The system of claim 7, 8 or 9 wherein the temperature of the liquid remains lower than a boiling temperature of the liquid when the liquid is within the first heat exchanger.
11. The system of claim 7, 8, 9 or 10 wherein the cooling fluid is a second vapour stream.
12. The system of any one of claims 7 to 11 including sensor means for sensing a temperature of the liquid exiting the first heat exchanger, and control means adapted to control a rate of flow of the liquid stream to ensure that the liquid does not boil within the first heat exchanger.
13. A power generation system including a first heat exchanger for transferring heat from a first vapour stream to a liquid in a closed circuit, means for circulating the liquid around the closed circuit, and a second heat exchanger for transferring heat from the liquid to a cooling fluid, wherein the second heat exchanger is provided . with at least one thermoelectric generator which has a hot junction in thermal contact with the liquid and a cold junction in thermai contact with the cooling fluid.
14. A system for transferring heat from a first vapour stream to a cooling fluid substantially as herein described with reference to the accompanying drawings.
PCT/AU2007/001024 2006-07-25 2007-07-25 System and method of heat transfer WO2008011666A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NZ54875906 2006-07-25
NZ548759 2006-07-25

Publications (1)

Publication Number Publication Date
WO2008011666A1 true WO2008011666A1 (en) 2008-01-31

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Application Number Title Priority Date Filing Date
PCT/AU2007/001024 WO2008011666A1 (en) 2006-07-25 2007-07-25 System and method of heat transfer

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WO (1) WO2008011666A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140238050A1 (en) * 2012-05-14 2014-08-28 Hyundai Heavy Industries Co., Ltd. System and method for processing liquefied gas

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0496283A2 (en) * 1991-01-25 1992-07-29 Linde Aktiengesellschaft Process for evaporating liquid natural gas
WO2001014807A1 (en) * 1999-08-25 2001-03-01 Messer Griesheim Gmbh Method and device for transmitting coldness
EP1637825A2 (en) * 2004-09-17 2006-03-22 Karl Mittermayr Intermediate heat exchanger, heat pump and cooling system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0496283A2 (en) * 1991-01-25 1992-07-29 Linde Aktiengesellschaft Process for evaporating liquid natural gas
WO2001014807A1 (en) * 1999-08-25 2001-03-01 Messer Griesheim Gmbh Method and device for transmitting coldness
EP1637825A2 (en) * 2004-09-17 2006-03-22 Karl Mittermayr Intermediate heat exchanger, heat pump and cooling system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140238050A1 (en) * 2012-05-14 2014-08-28 Hyundai Heavy Industries Co., Ltd. System and method for processing liquefied gas
EP2851546A4 (en) * 2012-05-14 2016-03-23 Hyun Dai Heavy Ind Co Ltd System and method for processing liquefied gas
EP2851547A4 (en) * 2012-05-14 2016-04-27 Hyun Dai Heavy Ind Co Ltd System and method for processing liquefied gas
EP2851544A4 (en) * 2012-05-14 2016-05-04 Hyun Dai Heavy Ind Co Ltd System and method for processing liquefied gas
CN104220739B (en) * 2012-05-14 2017-02-22 现代重工业株式会社 system and method for processing liquefied gas
US9885446B2 (en) 2012-05-14 2018-02-06 Hyundai Heavy Industries Co., Ltd. System and method for processing liquefied gas

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