EP0235996A1 - Wärmeaustauscher - Google Patents

Wärmeaustauscher Download PDF

Info

Publication number
EP0235996A1
EP0235996A1 EP87301302A EP87301302A EP0235996A1 EP 0235996 A1 EP0235996 A1 EP 0235996A1 EP 87301302 A EP87301302 A EP 87301302A EP 87301302 A EP87301302 A EP 87301302A EP 0235996 A1 EP0235996 A1 EP 0235996A1
Authority
EP
European Patent Office
Prior art keywords
bodies
chambers
heat exchanger
exchanger according
heat
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Withdrawn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
EP87301302A
Other languages
English (en)
French (fr)
Inventor
William Robert Laws
Geoffrey Ronald Reed
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.)
ENCOMECH ENGINEERING DEVELOPMENTS Ltd
Original Assignee
ENCOMECH ENGINEERING DEVELOPMENTS Ltd
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 ENCOMECH ENGINEERING DEVELOPMENTS Ltd filed Critical ENCOMECH ENGINEERING DEVELOPMENTS Ltd
Publication of EP0235996A1 publication Critical patent/EP0235996A1/de
Withdrawn legal-status Critical Current

Links

Images

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
    • F28D19/00—Regenerative heat-exchange apparatus in which the intermediate heat-transfer medium or body is moved successively into contact with each heat-exchange medium
    • F28D19/02—Regenerative heat-exchange apparatus in which the intermediate heat-transfer medium or body is moved successively into contact with each heat-exchange medium using granular particles

Definitions

  • This invention relates to heat exchangers in which heat is transferred between gaseous media.
  • Such heat exchangers are known in which the heat is transferred from a donor flow to an acceptor flow by conduction through a separating wall between the flows. Since there is a temperature gradient through the wall, related to its conductivity, the heat transfer is limited thereby and the acceptor gas outlet temperatures are considerably lower than the donor gas inlet temperatures.
  • regenerative heat exchangers comprising stoves that contain a heat-­absorbing mass.
  • the heating gas e.g. a furnace off-gas
  • the acceptor gas e.g. furnace combustion air
  • the exhaust gas also flows alternately through each stove but in opposite phase to the exhaust gas, so that while one stove is receiving heat from the hot gas the other is giving it up to the combustion air.
  • the alternating exposures of the heat-absorbing medium may be be controlled by valves that switch the two stoves, or in a continuous arrangement the heat-­absorbing medium is transferred between stoves continuously, as in a rotary regenerative heat exchanger, so that the waste gas and combustion air do not have to be diverted.
  • a heat exchanger comprising respective chambers for the flow of donor and acceptor gases, connection means between said chambers establishing a closed path extending through said chambers, and means for circulating a quantity of solid bodies around said path to transfer heat between the respective gases.
  • the bodies being used as a heat transfer medium should preferably substantially fill the connection means defining said path between said chambers so as to offer a high resistance to any leakage gas flow therethrough. Preferably, they also substantially fill the chambers themselves so as to optimise the exposure of the gas flows to the heat exchange bodies.
  • a mass of small bodies may be used, preferably generally spherical in form and, they may be composed of or have an outer coating of a desired chemical reagent so that they can promote a chemical reaction with one or more of the gas flows as well as transfer heat between the chambers.
  • Drive means for maintaining the circulation of the bodies through the chambers are preferably disposed in the connection means between the chambers, and it is further preferred to have such drive means in the path of the cooled bodies before they are reheated by the donor flow.
  • the drive means may comprise a screw conveyor or a drag link or chain conveyor, e.g. in the form of a bucket chain or a scraper conveyor or an entrainment chain (sometimes known as an "en masse" conveyor).
  • the bodies are allowed to flow by gravity through the chambers from donor gas flow chamber to acceptor gas flow chamber.
  • a closed circulation path which comprises a plurality of branches in parallel where the flow of the bodies is distributed between a plurality of donor gas chambers and/or acceptor gas chambers.
  • a plurality of donor gas chambers and/or acceptor gas chambers may be connected in parallel to a common recirculating conduit.
  • a recuperative heat exchanger comprising two insulated containers or stoves 2a, 2b with inlet and outlet hoods 4 at their upper and lower ends forming chambers in communication with substantially smaller diameter vertical ducts 6a, 6b in each of which a respective conveyor screw 8 is mounted, driven by an external motor 8 ⁇ .
  • the ducts 6 thus connect the bottom of each container 2 to the top of the other and a continuous circulation path is provided for a mass of small heat absorbing bodies, in particular balls 10 (see for example Fig. 4), that substantially fill the interior space of the heat exchanger.
  • first container 2a high temperature gases enter through a lower port 12 and exit through an upper port 14 after passing through the heat absorbing bodies 10 in the chamber and the heated bodies are progressively transferred from the bottom of the first container, by the first conveyor screw 8a, to enter the top of the second container 2b.
  • combustion air to be heated enters through a lower port 16 and absorbs heat from the bodies 10 before exiting through a top outlet 18 from the container.
  • the second conveyor screw 8b transfers the bodies from the bottom of the second container 2b to the top of the first container 2a where they can be reheated. The heat exchange process is thus carried out continuously.
  • the two conveyor screws 8 are synchronised so that they transfer heat absorbing bodies 10 at a corresponding rate. It is possible to arrange, nevertheless, that the rate can be varied, whereby with constant gas flows in both chambers the outlet temperatures can be adjusted.
  • Fig. 3 illustrates the container construction in cross-section.
  • the insulating layer lines a supporting metal shell 26 which is covered by back-up insulation 28, e.g. a mineral wool, protected by a final outer cover 30 which may be required to form a weatherproof cladding.
  • the ducts between the containers may be similarly insulated.
  • the ducts 6 are substantially sealed as far as any gas flow is concerned so that no more than a minimal rate of cross-leakage will occur, e.g. 1-29% of the gas flows through the chambers themselves, corresponding to a pressure drop through the ducts some 50 times that through the containers.
  • a minimal rate of cross-leakage e.g. 1-29% of the gas flows through the chambers themselves, corresponding to a pressure drop through the ducts some 50 times that through the containers.
  • there can be a very large difference between the cross-­sectional areas of the containers and the ducts e.g. in excess of 80:1, which implies a maximum leakage flow of 1:80 in comparison with the gas flows in the containers themselves.
  • the sealing effect in the conduits is also influenced by the contents of each conduit acting as a labyrinth seal to result in a substantially increased pressure drop, and the effect can be enhanced by a number of measures in addition to reducing the duct cross-sections in relation to the container cross-sections.
  • the clearances between the conveyor screws and the duct walls are kept to a minimum and the conveyor screw is given a relatively fine pitch.
  • Fig. 4 illustrates a modification of the heat exchanger to adapt it for operation in this manner in which, after the particles in the spaces between the bodies have been carried to the top of the conveyor duct, they are separated from the bodies to prevent the particles from entering the following chamber. This is done by providing a sloping face 34 between conveyor duct 6 and the container 2, in which face there is a screen or sieve plate 36. The screen mesh is too small for the bodies 10 but the particles can pass through the screen into a further duct 38 leading to the base or entry region of the conveyor duct 6. The particles are thus circulated continually through the conveyor duct to restrict gas flow through the spaces that exist between the spherical bodies in the duct but they bypass the following heat exchange chamber so that they do not obstruct the gas flow there.
  • Each of the conveyor ducts 6 may be provided with such a circulating flow of particulate material, but in the case of a regenerative heat exchanger for furnace gases the greater pressure differential will exist between the combustion air outlet and the exhaust gas inlet, so that the duct between those points would have the leakage-restriction means if only one duct were to be so provided. It is also possible to give the particulate material a circulatory path in which it flows alternately through each duct 6a, 6b, restricting any gas flow through both while bypassing the chambers themselves, this does, however, have the disadvantage that as compared with a particle flow circulating only through the duct carrying the bodies heated to their maximum temperature, those bodies will be subject to more cooling before they come into contact with the acceptor gas.
  • Fig. 5 a modified arrangement is shown in which the two containers 2a, 2b are mounted one above the other with the heating gas passing through the upper container 2a so that the bodies 10 heated there flow by gravity through a second insulated duct 6 ⁇ to the lower container 2b.
  • a conveyor screw shrouded in the duct 6 transfers the cooled bodies back to the top entry region of the upper container.
  • a higher maximum temperature can be maintained because a mechanical drive is not required to move the heat absorbing bodies between the upper to the lower container, when the bodies are at their hottest.
  • the chambers are linked by a gravity feed, the flow of the bodies between the chambers is self-­synchronizing.
  • Fig. 6 shows a heat exchanger similar to that in Fig. 5 but in which the two insulated containers 2a, 2b have different volumes, to provide a larger chamber for the acceptor gas flow than for the donor gas flow. As compared with the previous example, this allows a larger volume of gas to be heated, albeit to a lower maximum temperature, with a lower pressure drop because of the increased cross-section.
  • a lateral offset between the two chambers 2a, 2b is provided to leave an inclined bottom wall 40 in the passage between the containers.
  • the hot gas is produced by the combustion of coal or some other fuel that contains sulphur
  • a heat exchanger according to the invention to reduce the sulphur emission level by coating the heat absorbing bodies with a suitable material such as limestone or dolomite which will react with and fix sulphur in the gas.
  • a suitable material such as limestone or dolomite which will react with and fix sulphur in the gas.
  • the material would be fully calcined (CaCo3 ⁇ CaCO + CO2) and because the very large surface area of the bodies is constantly abraded to expose fresh material, this reaction can be maintained at a high efficiency.
  • regular replacement of the bodies would be required to replenish the supply of reactant, at a rate of about the same order of magnitude as the sulphur content in the hot gas.
  • CaCo3 as a powder or in fine pellet form, such material possibly being injected with the incoming hot gas.
  • these small particles can be removed with the ash in the manner illustrated in Figs. 7 and 8.
  • the sulphur-fixing reaction may be accelerated by the presence of a suitable catalyst either in the material of the bodies themselves, or as a coating on the bodies, or as a separate additive.
  • a modified configuration such as that shown in Fig. 9 can be employed to reduce the overall height.
  • the two insulated containers 2a, 2b are mounted with their longitudinal axes oppositely inclined at a relatively small angle only marginally greater than the angle of repose of the bodies 10.
  • a conveyer screw in the insulated duct 6 transfers the cooled bodies from the lower container to the upper container.
  • the bodies heated in the upper container are transferred by gravity through a short insulated duct 6 ⁇ at their opposite, closer ends.
  • This latter duct which may have its axis canted out of the vertical plane, has a length that is calculated to give an acceptable compromise as regards the limitation of cross-leakage of gases between the containers and the restriction of the overall height of the apparatus.
  • a further embodiment of the invention is illustrated in which three pairs of the insulated containers 2a,2b are connected in parallel to an insulated duct 6c, as in previous examples each pair of containers providing an upper chamber for the donor gas flow and a lower chamber for the acceptor gas flow.
  • a drag link conveyor 54 within the duct 6c raises the heat-absorbing bodies 10 from the acceptor gas chamber exits to return them to the donor gas chamber entries.
  • the conveyor 54 may take the form of a bucket chain conveyor, but preferably it is of the kind that moves the bodies in a continuous stream.
  • An example of such a conveyor is the Redler "en masse" elevator manufactured by Redler Limited of Stroud, Glos., England.
  • baffles 56a,56b at the exits of the first two chambers in the direction of travel of the conveyor limit the depth of deposition from these chambers onto the conveyor.
  • the baffles are so adjusted that a similar rate of deposition is maintained from each of the three exits and therefore a similar throughput rate is maintained in each pair of containers.
  • the apparatus can be operated so that temperature fluctuations in the acceptor gas flow can be reduced or removed, making the heat exchanger particularly suitable for many applications, e.g. for the heating of combustion air, where maintaining the air output at a constant temperature facilitates control of the furnace in which it is to be used.

Landscapes

  • 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)
EP87301302A 1986-02-17 1987-02-16 Wärmeaustauscher Withdrawn EP0235996A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8603896 1986-02-17
GB868603896A GB8603896D0 (en) 1986-02-17 1986-02-17 Heat exchangers

Publications (1)

Publication Number Publication Date
EP0235996A1 true EP0235996A1 (de) 1987-09-09

Family

ID=10593198

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87301302A Withdrawn EP0235996A1 (de) 1986-02-17 1987-02-16 Wärmeaustauscher

Country Status (2)

Country Link
EP (1) EP0235996A1 (de)
GB (1) GB8603896D0 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0288141A2 (de) * 1987-03-23 1988-10-26 Torftech Limited Behandlung von Stoff in flüssigem Zustand
US5259444A (en) * 1990-11-05 1993-11-09 Masachusetts Institute Of Technology Heat exchanger containing a component capable of discontinuous movement

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1904153A (en) * 1927-03-26 1933-04-18 Fuller Lehigh Co Heating combustion air for a furnace
US2745656A (en) * 1951-06-11 1956-05-15 Phillips Petroleum Co Apparatus and method for controlling temperatures of hot gas lift for pebbles
FR1177523A (fr) * 1956-08-31 1959-04-27 Air Preheater échangeur de chaleur à grains
US3067131A (en) * 1961-03-27 1962-12-04 Socony Mobil Oil Co Inc Periodic introduction of granular contact material into high pressure vessel
US3104955A (en) * 1957-08-01 1963-09-24 Continental Aviat & Eng Corp Heat exchanger
CH413883A (de) * 1963-09-02 1966-05-31 Siemens Ag Mit Masseteilchen als Wärmeträger arbeitende Wärmeaustauschvorrichtung
GB1113176A (en) * 1965-08-03 1968-05-08 Marshall Bauder Heat exchange unit
DE1501567A1 (de) * 1966-08-22 1970-01-15 Linde Ag Verfahren und Vorrichtung zum indirekten Waermeaustausch zwischen Fluessigkeiten
EP0016713A1 (de) * 1979-03-27 1980-10-01 Tunzini-Nessi Entreprises D'equipements Verfahren zur Wärmerückgewinnung aus einem fliessenden warmen Gas und Vorrichtung zur Durchführung des Verfahrens
DE3407341A1 (de) * 1984-02-29 1985-08-29 Peter 4630 Bochum Kähmann Waermeaustauscher

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1904153A (en) * 1927-03-26 1933-04-18 Fuller Lehigh Co Heating combustion air for a furnace
US2745656A (en) * 1951-06-11 1956-05-15 Phillips Petroleum Co Apparatus and method for controlling temperatures of hot gas lift for pebbles
FR1177523A (fr) * 1956-08-31 1959-04-27 Air Preheater échangeur de chaleur à grains
US3104955A (en) * 1957-08-01 1963-09-24 Continental Aviat & Eng Corp Heat exchanger
US3067131A (en) * 1961-03-27 1962-12-04 Socony Mobil Oil Co Inc Periodic introduction of granular contact material into high pressure vessel
CH413883A (de) * 1963-09-02 1966-05-31 Siemens Ag Mit Masseteilchen als Wärmeträger arbeitende Wärmeaustauschvorrichtung
GB1113176A (en) * 1965-08-03 1968-05-08 Marshall Bauder Heat exchange unit
DE1501567A1 (de) * 1966-08-22 1970-01-15 Linde Ag Verfahren und Vorrichtung zum indirekten Waermeaustausch zwischen Fluessigkeiten
EP0016713A1 (de) * 1979-03-27 1980-10-01 Tunzini-Nessi Entreprises D'equipements Verfahren zur Wärmerückgewinnung aus einem fliessenden warmen Gas und Vorrichtung zur Durchführung des Verfahrens
DE3407341A1 (de) * 1984-02-29 1985-08-29 Peter 4630 Bochum Kähmann Waermeaustauscher

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0288141A2 (de) * 1987-03-23 1988-10-26 Torftech Limited Behandlung von Stoff in flüssigem Zustand
EP0288141A3 (de) * 1987-03-23 1990-03-07 Torftech Limited Behandlung von Stoff in flüssigem Zustand
US5259444A (en) * 1990-11-05 1993-11-09 Masachusetts Institute Of Technology Heat exchanger containing a component capable of discontinuous movement
USRE37134E1 (en) 1990-11-05 2001-04-17 Massachusetts Institute Of Technology Heat exchanger containing a component capable of discontinuous movement

Also Published As

Publication number Publication date
GB8603896D0 (en) 1986-03-26

Similar Documents

Publication Publication Date Title
US6230633B1 (en) Conveyor/cooler of loose materials
US4307773A (en) Fluid bed heat exchanger for contaminated gas
US5505907A (en) Apparatus for treating or utilizing a hot gas flow
US4624636A (en) Two stage material cooler
US5634516A (en) Method and apparatus for treating or utilizing a hot gas flow
CA1316691C (en) Process of melting silicate raw materials, particularly in the production of mineral wool, and apparatus for preheating the mixture of raw materials and apparatus for purifying the tank exhaust gases
GB1576440A (en) Apparatus and method for the continous thermal treatment of solid substances
KR950704643A (ko) 순환 유동상 시스템을 구동시키는 방법 및 장치(method and apparatus for operating a circulating fluidized bed reactor system)
EP0431163B1 (de) Wirbelbettofen mit verbundumlauf
EP0235996A1 (de) Wärmeaustauscher
FI103590B (fi) Laite ja menetelmä aineiden ja lämmön talteenottamiseksi leijukerrospoltosta
EP0174976A1 (de) Vorrichtung zur reinigung von gas.
US4238216A (en) Heating glass batch material
KR930011376B1 (ko) 분말입자 재료의 예열장치
CN1061427C (zh) 包括有分离器－冷却器的流化床反应器及其操作方法
US2276496A (en) Means for cooling material
US3730849A (en) Integral calcined coke cooler
SU1083925A3 (ru) Устройство дл термообработки агрегатного материала газовым потоком
US3619422A (en) Process of drying sewage sludge
CN100393842C (zh) 冶金焦炭镀碳增强装置
SU1121571A1 (ru) Многозонна печь кип щего сло дл обжига сыпучего материала
JP3022907B2 (ja) 流動床焼成炉
SU1104347A1 (ru) Устройство дл подогрева шихты
RU2059180C1 (ru) Обжиговая машина конвейерного типа
SU996830A1 (ru) Обжигова машина конвейерного типа

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): BE DE ES FR GB IT LU NL

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19880310

RIN1 Information on inventor provided before grant (corrected)

Inventor name: LAWS, WILLIAM ROBERT

Inventor name: REED, GEOFFREY RONALD