EP0181614A1 - Procédé et appareil d'échange de chaleur gaz-liquide - Google Patents

Procédé et appareil d'échange de chaleur gaz-liquide Download PDF

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Publication number
EP0181614A1
EP0181614A1 EP85114212A EP85114212A EP0181614A1 EP 0181614 A1 EP0181614 A1 EP 0181614A1 EP 85114212 A EP85114212 A EP 85114212A EP 85114212 A EP85114212 A EP 85114212A EP 0181614 A1 EP0181614 A1 EP 0181614A1
Authority
EP
European Patent Office
Prior art keywords
tubes
fluoropolymer
gaseous stream
diameter
tube
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP85114212A
Other languages
German (de)
English (en)
Inventor
Robert Thomas Bosworth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ametek Inc
Original Assignee
Ametek Inc
EI Du Pont de Nemours and Co
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 Ametek Inc, EI Du Pont de Nemours and Co filed Critical Ametek Inc
Publication of EP0181614A1 publication Critical patent/EP0181614A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/007—Auxiliary supports for elements
    • F28F9/013—Auxiliary supports for elements for tubes or tube-assemblies
    • F28F9/0131—Auxiliary supports for elements for tubes or tube-assemblies formed by plates
    • 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
    • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
    • F28D7/0058—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for only one medium being tubes having different orientations to each other or crossing the conduit for the other heat exchange medium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
    • F28F21/06—Constructions of heat-exchange apparatus characterised by the selection of particular materials of plastics material
    • F28F21/062—Constructions of heat-exchange apparatus characterised by the selection of particular materials of plastics material the heat-exchange apparatus employing tubular conduits

Definitions

  • a wide variety of heat exchange apparatus has been used for treatment of exit gases from process streams, particularly those containing corrosive elements such as combustion gases.
  • combustion gases typically contain oxides of sulfur and nitrogen that can form highly corrosive acids. These acids have restricted the materials that can be used in heat exchange apparatus when the gas is cooled below its dew point.
  • heat exchange elements have, in the past. been prepared from glass, copper, and copper covered with fluoropolymer.
  • highly structured arrangements of fluoropolymer tubes have been suggested, such as in Withers U.S. Patent 3.435.893.
  • the instant invention provides, in a process for changing the temperature of a gaseous stream by passing the stream through a heat exchanger maintained at a temperature different from that of the gaseous stream by circulating a heat transfer maximu through the heat exchanger, the improvement wherein the heat exchanger comprises a bank of fluoropolymer tubes having a diameter of about from 3 to 10 mm and a free span for each tube segment of about from 20 to 90 cm: the gaseous stream is passed across at least five rows of tubes through which the heat transfer medium is circulated: the tubes are arranged to provide center to center spacing between the tubes of about from 1.25 to 3.0 times the diameter of the tubes: the gaseous stream has a velocity to provide a Reynolds number, through the bank of tubes, of about from 800 to 3000; and wherein the ratio of free span to tube diameter is about from 50 to 150.
  • the heat exchanger comprises a bank of fluoropolymer tubes having a diameter of about from 3 to 10 mm and a free span for each tube segment of about from 20 to 90
  • the present invention further provides, in an apparatus for changing the temperature of a gaseous stream having a given velocity comprising a passage and a heat exchanger positioned transverse to the passage, the improvement wherein the heat exchanger comprises a bank of tubes of fluoropolymer having a diameter of about from 3 to 10 mm and a free span for each tube segment of about from 20 to 90 cm; the passage intersects at least five rows of tubes through which a heat transfer medium is circulated; the tubes are arranged to provide center to center spacing between the tubes of about from 1.25 to 3.0 times the diameter of the tubes: and wherein the ratio of the free span to the tube diameter is about from 50 to 150; the parameters being selected to provide a Reynolds number through the bank of tubes of about from 800 to 3000 at the velocity of the gaseous stream.
  • the heat exchanger comprises a bank of tubes of fluoropolymer having a diameter of about from 3 to 10 mm and a free span for each tube segment of about from 20 to 90 cm; the passage intersects at least five rows of tubes
  • FIG. 1 The present invention is illustrated in Figure 1. in which gaseous stream 1 is passed into a heat exchanger through inlet 2 and expanded section 3. Tubes 4 in the heat exchanger extend from tube sheets 5 and 5A positioned at either end of the tubes. The tubes are separated by spacers 6, which serve the dual purpose of.regulating the free span of each tube segment between spacers at a distance of about from 20 to 90 cm, and separating successive rows of tubes by about from 1.25 to 3.0 times the diameter of the tubes. After passing through the heat exchanger, the gaseous stream continues through outlet 8.
  • each tube segment of about from 20 to 90 cm permits a low frequency, high amplitude vibration of the tubes that has the dual benefit of a self-cleaning function and an increase in the heat transfer coefficient of the tubes.
  • the tubes and spacers can be better seen in Figure 2, wherein spacers 6 are used in conjunction with rods 9 to maintain the desired free length between spacers.
  • the tubes pass through apertures 10 formed in the spacers.
  • the spacers form arrays of at least five rows of tubes in the direction of flow, which can be arranged in any desired configuration, including, for example, a square configuration, as shown, or a triangular configuration.
  • a square configuration as shown, or a triangular configuration.
  • the square configuration provides lower pressure drop in the gaseous stream, while the triangular configuration results in higher heat transfer.
  • the polymeric tubes can be prepared from a wide variety of fluoropolymers. which have been found to give a combination of desirable heat transfer properties, resistance to the corrosive effects of the gaseous stream, and excellent resistance to fouling.
  • Particularly desirable are polymers of tetrafluoroethylene, copolymers of tetrafluoroethylene and hexafluoropropylene as described in U.S. Patent 2,946,763 and copolymers of tetrafluoroethylene and perfluoropropyl vinyl ether as described in U.S. Patent 3.132, 123.
  • Still other fluoropolymers which can be used in the present invention include polyvinylidene difluoride and copolymers of polytetrafluoroethylene and chloro-trifluoroethylene.
  • conductive particles can be incorporated in the fluoropolymer for further improved heat transfer characteristics, as described in Reilly et al. U.S. Patent 3.718,181, hereby incorporated by reference. Graphite particles are particularly preferred.
  • the tube sheets used at the end of the heat exchange units can be prepared by techniques known in the art, such as described in Withers U.S. Patent 3,315,740. also hereby incorporated by reference.
  • the Reynolds number of the gaseous stream through the bank of tubes is about from 800 to 3000 and preferably about from 1000 to 2000.
  • the Reynolds number is calculated, as is known in the art. as the velocity of flow through the tube bank based on the minimum cross-sectional free area, times the tube diameter times the gas density divided by the gas viscosity.
  • the required Reynolds number can be attained by adjustment of the velocity of the gas entering the tube bank, or adjustment of the size and spacing of the tubes, or both.
  • the gaseous stream that is heated or cooled according to the present invention can contain a variety of corrosive elements, including oxides of sulfur and nitrogen that can form corrosive acids.
  • the temperature of the gas stream should be about from 80° to 240°C. Temperatures in excess of 240°C can adversely effect the fluoropolymer tubes, while little practical benefit is attained in the treatment of gas streams below 80°C, since reduction of gas temperature significantly below this level reduces its natural tendency to rise.
  • a test bundle of about 650 hollow flexible tubes of tetrafluoroethylene/perfluorovinyl ether copolymer was made by stringing tubing through holes in the top and bottom of a clear acrylic box which was 46 cm high and 46 cm wide.
  • the tubes had a diameter of 4.75 mm and were threaded through spacers of the same clear acrylic resin inside the test box such that these spacers could be removed to the top of the test chamber out of the way of the air stream or be placed along the vertical length of the tubes to provide a free span for each tube segment of from 15 to 46 cm.
  • the tubes were arranged in a square hole layout. Heat exchange elements were prepared with 20 rows of tubes. The tubes were spaced at a distance of about 2.0 times the tube diameter. The ends were bonded together to form a tube sheet as described in U.S. Patent 3,315.740.
  • the module was placed in a wind tunnel and pressure drop measurements were made at air velocities corresponding to Reynolds numbers ranging from about 400 to about 10,000.
  • a steam line was attached to the top tube sheet such that up to 30 psig saturated steam could be introduced into the tube bank to heat the air.
  • the condensed steam leaving the tube bank was discharged through a trap to the drain. Pressure, flow and temperature measurements were taken such that the overall heat transfer coefficient and pressure drop across the tube bank could be determined at various air velocities.
  • Air velocity across the tube bank was measured with an industrial anemometer which was calibrated against a DISA scientific constant temperature anemometer.
  • the heat flow from the tubes to the air was determined by measuring the temperature of the air stream before and after the heat exchange module with J-type thermocouples. Heating steam pressures of 7 and 15 psig were used. The air velocity was varied over a range to cover the laminar, transitional and turbulent flow regimes.
  • the outside film coefficient, h o is expressed as a dimensionless number J b
  • Vibrations of the tubes were observed when the Reynolds number of the air flow was more than about 800.
  • the amplitude of vibration was visibly large and exceeded two tube diameters in many cases.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
EP85114212A 1984-11-07 1985-11-07 Procédé et appareil d'échange de chaleur gaz-liquide Withdrawn EP0181614A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US66897284A 1984-11-07 1984-11-07
US668972 1984-11-07

Publications (1)

Publication Number Publication Date
EP0181614A1 true EP0181614A1 (fr) 1986-05-21

Family

ID=24684505

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85114212A Withdrawn EP0181614A1 (fr) 1984-11-07 1985-11-07 Procédé et appareil d'échange de chaleur gaz-liquide

Country Status (2)

Country Link
EP (1) EP0181614A1 (fr)
JP (1) JPS61116292A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0291322A1 (fr) * 1987-05-14 1988-11-17 Du Pont Canada Inc. Procédé pour la fabrication d'un faiscaux de tubes pour un échangeur de chaleur
US5211220A (en) * 1988-06-21 1993-05-18 Sigri Great Lakes Carbon Gmbh Tube for a shell and tube heat exchanger and process for the manufacture thereof
FR2793011A1 (fr) * 1999-04-29 2000-11-03 Valeo Thermique Moteur Sa Echangeur de chaleur a tubes souples, notamment pour vehicule automobile

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE463785B (sv) * 1988-11-01 1991-01-21 Infrasonik Ab Foerfarande och anordning foer att med hjaelp av laagfrekvent ljud forcera vaermetransmission mellan kroppar och gaser
SE463786B (sv) * 1988-11-01 1991-01-21 Infrasonik Ab Foerfarande och anordning foer att med hjaelp av laagfrekvent ljud forcera vaermetransmission mellan kroppar och gaser

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3132123A (en) * 1960-11-25 1964-05-05 Du Pont Polymers of perfluoroalkoxy perfluorovinyl ethers
US3417812A (en) * 1966-11-30 1968-12-24 Du Pont Heat exchanger apparatus with a novel by-passing arrangement for shellside flow
US3718181A (en) * 1970-08-17 1973-02-27 Du Pont Plastic heat exchange apparatus
US3805881A (en) * 1971-08-17 1974-04-23 Du Pont Fluid heat exchange system
US4271900A (en) * 1978-06-28 1981-06-09 E. I. Du Pont De Nemours And Company Apparatus with expandable tube bundle

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5517319A (en) * 1978-07-22 1980-02-06 Sankin Kogyo Kk Preparation of eugenol zinc salt
JPS58214784A (ja) * 1982-05-28 1983-12-14 ヌ−ベル・アプリカシオン・テクノロジク 熱交換要素及び蓄熱器

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3132123A (en) * 1960-11-25 1964-05-05 Du Pont Polymers of perfluoroalkoxy perfluorovinyl ethers
US3417812A (en) * 1966-11-30 1968-12-24 Du Pont Heat exchanger apparatus with a novel by-passing arrangement for shellside flow
US3718181A (en) * 1970-08-17 1973-02-27 Du Pont Plastic heat exchange apparatus
US3805881A (en) * 1971-08-17 1974-04-23 Du Pont Fluid heat exchange system
US4271900A (en) * 1978-06-28 1981-06-09 E. I. Du Pont De Nemours And Company Apparatus with expandable tube bundle

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0291322A1 (fr) * 1987-05-14 1988-11-17 Du Pont Canada Inc. Procédé pour la fabrication d'un faiscaux de tubes pour un échangeur de chaleur
US4923004A (en) * 1987-05-14 1990-05-08 Du Pont Canada, Inc. Comfort heat exchanger
US5078946A (en) * 1987-05-14 1992-01-07 Du Pont Canada Inc. Method for the manufacture of a comfort heat exchanger
US5211220A (en) * 1988-06-21 1993-05-18 Sigri Great Lakes Carbon Gmbh Tube for a shell and tube heat exchanger and process for the manufacture thereof
FR2793011A1 (fr) * 1999-04-29 2000-11-03 Valeo Thermique Moteur Sa Echangeur de chaleur a tubes souples, notamment pour vehicule automobile
US6343646B1 (en) 1999-04-29 2002-02-05 Valeo Thermique Moteur Heat exchanger with flexible tubes especially for a motor vehicle

Also Published As

Publication number Publication date
JPS61116292A (ja) 1986-06-03

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Inventor name: BOSWORTH, ROBERT THOMAS