EP0028503A2 - Verfahren und Apparat zum Heizen einer Flüssigkeit unter Verwendung eines Schwefeloxyde und Wasser enthaltenden Gases - Google Patents

Verfahren und Apparat zum Heizen einer Flüssigkeit unter Verwendung eines Schwefeloxyde und Wasser enthaltenden Gases Download PDF

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Publication number
EP0028503A2
EP0028503A2 EP80303848A EP80303848A EP0028503A2 EP 0028503 A2 EP0028503 A2 EP 0028503A2 EP 80303848 A EP80303848 A EP 80303848A EP 80303848 A EP80303848 A EP 80303848A EP 0028503 A2 EP0028503 A2 EP 0028503A2
Authority
EP
European Patent Office
Prior art keywords
heat exchanger
pipe
fluid
heat exchange
combustion gases
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Withdrawn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
EP80303848A
Other languages
English (en)
French (fr)
Other versions
EP0028503A3 (de
Inventor
Peter Davies
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.)
ExxonMobil Technology and Engineering Co
Original Assignee
Exxon Research and Engineering 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 Exxon Research and Engineering Co filed Critical Exxon Research and Engineering Co
Publication of EP0028503A2 publication Critical patent/EP0028503A2/de
Publication of EP0028503A3 publication Critical patent/EP0028503A3/de
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H9/00—Details
    • F24H9/0005—Details for water heaters
    • F24H9/0036—Dispositions against condensation of combustion products
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/22—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating
    • F24H1/40—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water tube or tubes
    • 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
    • F28D7/10—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 being arranged one within the other, e.g. concentrically
    • F28D7/12—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 being arranged one within the other, e.g. concentrically the surrounding tube being closed at one end, e.g. return type

Definitions

  • the present invention relates to a method and apparatus for heating a fluid employing a gas containing sulfur oxides and water.
  • Hot gases containing sulfur oxides and water are commonly employed for heating in industry and are derived by burning fuels containing sulfur.
  • fuels containing sulfur are solid fuels such as coals and lignites and fluid fuels such as fuel oils and hydrocarbon gases.
  • a well-known problem arising from the use of such hot gases is that of acid corrosion which occurs when the temperature of the hot gases falls to the dew point and an acidic liquid condenses on metal parts such as the low temperature heat recovery tubes of a furnace or boiler.
  • the approach is not reliable because a change in the operating conditions of the furnace can change the strength of the acid deposited at each location so that materials which previously would not have been corroded become exposed to an acid strength which they may not be able to resist.
  • the present invention in one aspect, provides a method of heating a fluid employing a heating gas containing SO and H 2 0 which passes in heat exchange relationship with the outer surface of a heat exchanger through which the fluid is passed, wherein the heat exchanger comprises a multi-pipe heat exchanger, and unheated fluid is passed into an inlet of one pipe of the multi-pipe heat exchanger at a temperature below the acid dew point of the heating gas and discharged from an outlet of another pipe of the said multi-pipe heat exchanger at a temperature exceeding the acid dew point of the heating gas, and maintaining the flow of fluid through the multi-pipe heat exchanger at a rate such that the temperature of the outer surface of the multi-pipe heat exchanger is above the acid dew point of the heating gas.
  • the said other pipe is the outermost pipe of the multi-pipe heat exchanger, and the said one pipe is inwards of the said other pipe.
  • the fluid discharged from the multi-pipe heat exchanger preferably is conducted to another heat exchange means and, heated therein to a higher temperature.
  • the said other heat exchange means may be heated mainly by radiation from a flame in which a sulfur-containing fuel is burned to produce combustion gases.
  • the said combustion gases may form at least some of the said heating gas, and the multi-pipe heat exchanger may be heated mainly by convection from said combustion gases.
  • the invention provides apparatus for heating a fluid comprising at least one burner for burning a sulfur-containing fuel in a flame to produce combustion gases containing SO X and H 2 0, comprising heat exchange means through which the fluid can flow in indirect heat exchange relationship with combustion gases contacting the outer surface of the heat exchange means, wherein the heat exchange means comprises a multi-pipe heat exchanger having an inlet for unheated fluid at one end of one pipe and an outlet for heated fluid at-one end of another pipe of the multi-pipe heat exchanger, and comprising means for supplying fluid to the multi-pipe heat exchanger at a rate within a predetermined range to avoid the deposition of acid dew on the outer surface of the multi-pipe heat exchanger.
  • the apparatus may comprise a second heat exchange means connected to receive heated fluid from the outlet of the said other pipe of the multi-pipe heat exchanger.
  • the second heat exchange means may be so disposed relative to the burner that, during operation, a major part of the heat received by the second heat exchange means is by radiation from the flame.
  • the multi-pipe heat exchanger may be so constructed and/or arranged in the apparatus that, during operation, a major part of the heat received by the multi-pipe heat exchanger is by convection from the combustion gases.
  • the apparatus may comprise walls defining a conduit for the passage of combustion gases, the multi-pipe heat exchanger extending across said conduit and being fixedly attached to the walls thereof at one end only.
  • the heat transfer properties of the multi-pipe heat exchanger may be improved by providing extended surfaces such as fins and/or protrusions on one or more heat transfer surfaces thereof.
  • the multi-pipe heat exchanger may comprise one or more passes.
  • the furnace 10 comprises vertical walls 11 lined with refractory which define a number of sections of reduced horizontal-cross-sectional area at the higher levels and which sections are connected by, e.g., sloping sections.
  • the top section 12 is connected to a stack (not shown) for the discharge of combustion gases from the top of the furnace 10.
  • furnace floor 13 Near the base of the furnace are provided a suitable number of burners (not shown) supported by furnace floor 13.
  • the or each burner is supplied with fuel which is burned in a flame 14 above the furnace floor 13. In the vicinity of flame 14, there is intense radiation and at more remote locations above the flame, most of the heating effect of the flame is by convection through the medium of the combustion gases and hot excess air.
  • the process fluid which is to be heated is passed more or less countercurrently relative to the combustion gases so that cool fluid is employed to recover heat from the combustion gases near the top of the furnace mainly by convective heat transfer, and heated fluid is finally heated mainly by radiant heat transfer in the vicinity of the flame 14.
  • the process fluid enters the furnace 10 near the top via tube 15 and passes through one (or more) sets or banks of tubes 16 disposed in a convection section 17 of the furnace for recovery of heat from the hot combustion gases passing upwardly towards the top section 12 and stack from a lower section 18 comprising a firebox.
  • the fluid passes through t ⁇ bes 16 in a generally countercurrent path to the combustion gases and relatively hot fluid circulates from the tubes 16 to one or more banks of tubes 19 in the lower section 18 surrounding the flame wherein a major proportion of high temperature heat is recovered from the radiation in the lower section 18.
  • the fluid leaves the tube bank(s) 19 via outlet(s) 20 at a relatively high temperature.
  • FIG. 2 shows, in simplified form, an arrangement of heat reccvery tubes for use in the convection secticn 17 in accordance with the invention.
  • the fluid is heated employing a double pipe heat exchanger 21 extending across the convection section 17 and being supported at its end regions by the walls 22, 23 of the furnace around the section 17.
  • Double pipe heat exchangers are known per se, and in the illustrated arrangement, the cool fluid is passed into one end 24 of the central tube 25 of the heat exchanger 21 and circulates from the open opposite end of the central tube 25 into the surrounding annulus defined between the central tube 25 and an outer tube 26. Matters are so arranged that heat is recovered from the combustion gases at temperatures exceeding the acid dew point on the outer surface of the outer tube 26, thereby avoiding acid corrosion problems.
  • the heated fluid is recovered from outlet 27 and may be passed to further convective heat recovery units and/or to a radiant heat recovery tube bank as described in relation to Figure 1.
  • the arrangement of Figure 2 enables cold fluid to be heated to a temperature exceeding the acid dew point without causing acid dew point corrosion of the heat exchanger 21.
  • the heat exchanger 21 is fixed at one end only, preferably the end at which cold fluid enters and from where heated fluid is recovered. The other end is supported in such a manner that it is free to move to accommodate thermal expansion and contraction of the heat exchanger 21 and the furnace walls.
  • the cold fluid feed is completely separated from the fluid which recovers heat from the upwardly passing hot combustion gases giving a greater range of variability of throughputs of the cold fluid feed than in the embodiment of Figure 2 since the flow rate and initial temperature of the feed have less influence on the temperature of the outer surface of the heat exchanger 29.
  • the cold fluid feed is circulated into the entrance 30 of the lowest section of the central tube 31 and is recovered via an outlet 32 from the highest section of the central tube 31.
  • the fluid feed is circulated through tube 31 generally countercurrently to a fluid in the annular space 34 defined between the central tube 31 and an outer tube 33.
  • the flow rate and temperature of the fluid in the annular space 34 are so arranged that the lowest temperature on the outside of the outer tube 33 exceeds the acid dew point.
  • the fluid in the central tube 31 circulates countercurrently to the fluid in the annular space 34, and the latter enters the heat exchanger 29 via inlet 36 on or communicating with the upper, cooler pass of the heat exchanger 29 and is recovered at a higher temperature from an outlet 37 or communicating with the lower, hotter pass.
  • the temperature of the fluid in the cooler pass must be such that the temperature of the outer surface of'the wall thereof exceeds the acid dew point.
  • the outer tube 33 has flanged ends 38, 39 to permit access for cleaning, maintenance and repair.
  • the central tube 31 may also be furnished with flanges (not shown) or other means of attachment in the vicinity of the return bend 40 (e.g. where each end of the bend 40 is attached to the straight sections of the tube 33) for servicing and removal of the central tube 31.
  • the heat transfer surfaces contacted by one or both streams of fluid may be provided with fins or other extended heat transfer surfaces and/or furnished with baffles.
  • double pipe heat exchangers may be employed in series and/or parallel connection, and that they may be of the same type or different types.
  • heat exchangers having at least two pipes enclosed by the outermost pipe and that the thus said enclosed pipes may be arranged side-by-side within the enclosing pipe and/or one within another inside the enclosing pipe.
  • the invention has been more particularly described with reference to avoiding acid corrosion when heating a fluid in the convection section of a furnace or similar heating apparatus, the invention may be employed alternatively or additionally for heating a fluid elsewhere in a furnace or other heating apparatus.
  • acid corrosion has been observed on heat exchange tubes within the radiant heating section of a furnace when the temperature-of the fluid passing through such tubes is relatively low.
  • the heat exchange tubes which are subject to acid corrosion in the radiant section may be tubes in which a fluid is heated from a temperature below the local acid dew point to a higher temperature and is then conducted either (a) to heat exchange tubes in the same furnace or apparatus, or (b) to another item of equipment for further heating and/or utilization, or in part to both (a) and (b).
  • the heat transfer characteristics and/or sizes of the tubes are selected to provide an outer surface temperature exceeding the acid dew point for reasonable and/or acceptable ranges of flow rates and pressure drops.
  • At least the outermost tube of the multi-pipe heat exchanger may be convenient to form at least the outermost tube of the multi-pipe heat exchanger with a rectangular cross-section so that the -multi-pipe heat exchanger can be more easily interfitted with other items of equipment.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
EP80303848A 1979-11-01 1980-10-29 Verfahren und Apparat zum Heizen einer Flüssigkeit unter Verwendung eines Schwefeloxyde und Wasser enthaltenden Gases Withdrawn EP0028503A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB7937865A GB2062834A (en) 1979-11-01 1979-11-01 Method and apparatus for heating a fluid employing a heating gas containing sulphur oxides and water
GB7937865 1979-11-01

Publications (2)

Publication Number Publication Date
EP0028503A2 true EP0028503A2 (de) 1981-05-13
EP0028503A3 EP0028503A3 (de) 1981-07-15

Family

ID=10508911

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80303848A Withdrawn EP0028503A3 (de) 1979-11-01 1980-10-29 Verfahren und Apparat zum Heizen einer Flüssigkeit unter Verwendung eines Schwefeloxyde und Wasser enthaltenden Gases

Country Status (2)

Country Link
EP (1) EP0028503A3 (de)
GB (1) GB2062834A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0056312A2 (de) * 1981-01-09 1982-07-21 Foster Wheeler Energy Limited Luftvorwärmer
FR2784175A1 (fr) * 1998-10-02 2000-04-07 Gm Etscheid Anlagen Gmbh Plongeur-refroidisseur en particulier pour le refroidissement de liquides tels que vin et mout dans des futs
EP1391663A1 (de) * 2002-08-19 2004-02-25 Vaillant GmbH Vorrichtung zum Erwärmen von Wasser

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3170290D1 (en) * 1981-09-08 1985-06-05 Dow Chemical Nederland Heat exchanger and use thereof
GB2138555B (en) * 1983-04-19 1986-07-23 Davy Mckee Ag Process for utilising heat removed on cooling a flue gas stream
CN102862999B (zh) * 2012-09-14 2015-05-20 苏州市中衡压力容器制造有限公司 用于酸浸法从粉煤灰中提取氧化铝的结晶浓缩装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE254462C (de) *
DE315672C (de) *
FR632424A (de) * 1928-01-09
DE2338548A1 (de) * 1972-08-01 1974-02-21 Waagner Biro Ag Wandheizflaeche fuer dampferzeuger

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE254462C (de) *
DE315672C (de) *
FR632424A (de) * 1928-01-09
DE2338548A1 (de) * 1972-08-01 1974-02-21 Waagner Biro Ag Wandheizflaeche fuer dampferzeuger

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0056312A2 (de) * 1981-01-09 1982-07-21 Foster Wheeler Energy Limited Luftvorwärmer
EP0056312A3 (en) * 1981-01-09 1982-11-10 Foster Wheeler Energy Limited Air preheater
FR2784175A1 (fr) * 1998-10-02 2000-04-07 Gm Etscheid Anlagen Gmbh Plongeur-refroidisseur en particulier pour le refroidissement de liquides tels que vin et mout dans des futs
EP1391663A1 (de) * 2002-08-19 2004-02-25 Vaillant GmbH Vorrichtung zum Erwärmen von Wasser

Also Published As

Publication number Publication date
EP0028503A3 (de) 1981-07-15
GB2062834A (en) 1981-05-28

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Effective date: 19820621

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Inventor name: DAVIES, PETER