EP0389652A1 - Panneau radiateur catalytique - Google Patents

Panneau radiateur catalytique Download PDF

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Publication number
EP0389652A1
EP0389652A1 EP89105451A EP89105451A EP0389652A1 EP 0389652 A1 EP0389652 A1 EP 0389652A1 EP 89105451 A EP89105451 A EP 89105451A EP 89105451 A EP89105451 A EP 89105451A EP 0389652 A1 EP0389652 A1 EP 0389652A1
Authority
EP
European Patent Office
Prior art keywords
catalytic
diffusion layer
active layer
catalytically active
oxygen
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.)
Ceased
Application number
EP89105451A
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German (de)
English (en)
Inventor
Wolfgang Dr.Rer.Nat. Gajewski
Josef Dipl.-Ing. Sprehe
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.)
Siemens AG
Original Assignee
Siemens AG
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 Siemens AG filed Critical Siemens AG
Priority to EP89105451A priority Critical patent/EP0389652A1/fr
Publication of EP0389652A1 publication Critical patent/EP0389652A1/fr
Ceased 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
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/0027—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters using fluid fuel
    • F24H1/0045—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters using fluid fuel with catalytic combustion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/12—Radiant burners
    • F23D14/18—Radiant burners using catalysis for flameless combustion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46—Details, e.g. noise reduction means
    • F23D14/72—Safety devices, e.g. operative in case of failure of gas supply
    • F23D14/82—Preventing flashback or blowback
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2900/00—Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
    • F23C2900/9901—Combustion process using hydrogen, hydrogen peroxide water or brown gas as fuel

Definitions

  • the invention relates to a catalytic surface heating element for the combustion of a fuel gas - in particular hydrogen - with oxygen, each with a separate feed for the fuel gas and the oxygen, with a diffusion layer adjoining the feed for the fuel gas and one on the one facing away from the fuel gas feed Side of the diffusion layer arranged catalytically active layer.
  • the combustion zone is located on the side of the catalyst mat facing the air supply, which has a favorable effect on the heat radiation. It is a major advantage of this catalytic burner that no ignitable mixtures are formed, and therefore deflagrations are excluded during operation. However, it is a peculiarity of this catalytic burner that the combustion is incomplete both in the combustion of hydrocarbons and in the combustion of hydrogen.
  • the fuel gas concentration in the exhaust gas is in the percent range.
  • the invention has for its object to develop a catalytic surface heating element for the combustion of a fuel gas with pure oxygen or with air, in which on the one hand no ignitable mixtures can occur and which on the other hand nevertheless ensures the most complete possible combustion of the fuel gases used.
  • a particularly flat design of the catalytically active layer results if, in a particularly advantageous development of the invention, the catalytic activity in the catalytically active layer increases continuously from one side thereof to the opposite side. In this case, even the slightest delay in the reaction leads to an increase in the catalytic activity in the region in which hydrogen and oxygen are opposed.
  • a simplified construction of the catalytically active layer is obtained if, in an expedient embodiment of the invention, it is constructed from a medium-active layer and from a separate, highly active layer. This allows one layers to produce more uniform, albeit different, catalytic activity and to assemble the catalytically active layer from several such layers of different activity.
  • the mechanical strength, in particular shock resistance, of the catalytic surface heating element can be increased if the highly active side of the catalytically active layer is applied to a perforated plate (perforated plate, expanded metal plate or the like) serving as a support.
  • a perforated plate perforated plate, expanded metal plate or the like
  • the catalytically active layer is supported and on the other hand the supply of oxygen or air through the breakthroughs of the sheet is made possible.
  • the perforated sheet metal can consist of a material with high thermal conductivity.
  • the heat released is distributed evenly over the entire surface of the catalytically active layer.
  • the activity of the catalytically active layer which is strongly temperature-dependent, is uniformly high over its entire area. This prevents zones of higher and lower temperature or higher and lower catalytic activity from being able to form in the catalytically active layer.
  • this perforated plate serves as a radiation surface for the heat generated.
  • the diffusion layer can consist of a porous ceramic body with low thermal conductivity.
  • a porous ceramic body with low thermal conductivity.
  • the heat transfer to the rear of the panel radiator is reduced and at the same time the heat radiation on the front of the catalytic panel radiator, ie on the side of the perforated sheet, is increased.
  • such a solid ceramic body has the property of limiting the mass flow of the fuel gas to a maximum design value. This in turn increases operational safety considerably and at the same time favors the controllability of the heating output.
  • the pore radii of the ceramic layer during the combustion of hydrogen as fuel gas can be set so that they do not let oxygen through, but do allow hydrogen with a limited mass flow.
  • this measure reliably ensures that no ignitable mixtures can occur.
  • this also ensures that oxygen is always present in excess on the part of the catalytically active layer. This creates an essential prerequisite for operational safety and for a complete conversion of the fuel gas.
  • FIG. 1 shows a top view of the catalytic surface heating element 1.
  • the housing 2 of the catalytic surface heating element is shown broken away on the upper side.
  • the catalytic surface heating element 1 shown in the exemplary embodiment is installed in a housing 2 which is closed on all sides with the exception of the front end face.
  • the front end face 4 is closed in the exemplary embodiment by a perforated plate 6, which is provided with ribs 8 for better heat dissipation.
  • a perforated plate 6 is followed by a catalytically active layer 10 and, in turn, a diffusion layer 12.
  • Between the diffusion layer 12 and the rear wall 14 of the Ge house is an empty space 16. This is connected via a line connector 18 to a fuel gas line 20, in the present case to a hydrogen line.
  • a drip pan 22 for condensed water can be seen under the ribs.
  • the diffusion layer 12 is formed by a porous ceramic body, in the exemplary embodiment made of aluminum oxide. Its pore radii are set so that hydrogen gas can pass through, but not oxygen. This was achieved by setting its pores, as will be explained later, to a diameter of 100 nm, in the exemplary embodiment ⁇ 50 nm. Such a ceramic body has a high temperature resistance and a very low thermal conductivity.
  • the catalytically active layer 10 likewise consists of such a disk-shaped aluminum oxide ceramic body, only its pore radii are larger by at least a factor of 2 than in the diffusion layer.
  • the pore radii of the catalytically active layer are greater than 200 nm.
  • the side of the catalytically active layer 10 facing away from the diffusion layer 12 has a catalytic activity which is about a factor of 2 higher than that side of the catalytically active layer which faces the diffusion layer is. This factor can expediently be between 1.5 and approximately 10.
  • This mass flow is introduced evenly distributed on the opposite side of the diffusion layer 12 into the catalytically active layer 10 on the side with low catalytic activity.
  • the hydrogen oxidizes at operating temperature with the oxygen or atmospheric oxygen flowing through the perforated plate 6 and the catalytically active layer 10.
  • the fine pore radii of the diffusion layer of ⁇ 100 nm in diameter, but preferably of ⁇ 50 nm in diameter, prevent the oxygen from penetrating into the diffusion layer. The result of this is that the oxidation takes place almost exclusively in the side of the lower catalytic activity facing the diffusion layer.
  • the reason for this is the strong increase in catalytic activity with temperature.
  • the zone in which the oxidation of the fuel gas, here the hydrogen, takes place moves more and more in the direction to the less active side of the catalytically active layer, which is closer to the diffusion layer.
  • FIG. 3 In addition to the enlarged representation of a cross section through the diffusion layer 12 and the adjoining catalytically active layer 10, the concentration of the Fuel gas H2 and oxygen O2 shown. While the concentration of the hydrogen gas flowing through the diffusion layer 12 from above in this diagram decreases with the penetration depth due to the flow resistance in the diffusion layer, this decrease is due to the larger pore diameter of the catalytically active layer for the oxygen flowing into the catalytically active layer from below in the diagram negligible. The penetration depth of the oxygen is limited to the catalytically active layer because of the impermeability of the diffusion layer. The concentration of hydrogen progressively decreases after penetration into the layer of medium catalytic activity due to the onset of oxidation.
  • the concentration of oxygen also decreases.
  • the solid curves correspond to a predetermined operating temperature. The curves are drawn in dashed lines for a higher temperature and dotted lines for a lower temperature. It can be seen from this that in both cases no hydrogen can escape from the catalytically active layer because it would have to penetrate into areas of ever higher catalytic activity and ever greater excess of oxygen. So that there can be no local overheating or hypothermia, the perforated plate 6 consists of a good heat-conducting material that distributes the heat evenly over the entire cross-section of the catalytically active layer, because the catalytic activity increases sharply with the temperature also ensures a uniform catalytic activity.
  • this catalytic surface heating element 1 exhibits an inherent control behavior which is caused by the fact that the microporous ceramic of the diffusion layer 12 limits the hydrogen mass flow to the design value even at the maximum concentration difference and temperature. Furthermore, the increase in volume as a result of the heating of the gases reacting with one another, ie in the Embodiment of hydrogen and oxygen, a pressure balance.
  • microporous ceramic of the diffusion layer represents a barrier to the oxygen, which on the one hand means that no ignitable mixtures can occur and on the other hand in connection with the other pores and the consequently lower flow resistance of the catalytically active layer compared to the diffusion layer leads to the fact that the hydrogen in the catalytically active layer is completely converted by the oxygen which is always present in excess.
  • the catalytic surface heating element 1 also shows a favorable behavior at part load, because the increasing activity and increasing oxygen concentration of the catalytically active layer 10 with increasing distance from the diffusion layer prevents unburned hydrogen gas from being able to pass through the catalytically active layer 10.
  • the heating power of the panel radiator can be easily adjusted by regulating the mass flow of hydrogen.
  • the low thermal conductivity of the ceramic layer, in particular the diffusion layer ensures that the heat is dissipated essentially to the front through the well heat-conducting perforated plate and not to the rear. Because of their low thermal conductivity, the ceramic layers heat up so much even at low output that they have a sufficiently high temperature and therefore also high catalytic activity even at partial load. This prevents unburned hydrogen gas from escaping through the perforated plate 6 even at partial load.
  • the pore size of the diffusion layer can be adjusted by using finely ground material with a primary grain size of ⁇ 10 nm as the starting material. This material is processed in an aqueous solution to form a slip, which is dried, shaped and finally processed by careful calcining to form a correspondingly shaped disk.
  • the temperature and above all the time during which the material is calcined must be kept as small as possible, because grain growth takes place at the expense of the small pores during the calcination.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Gas Burners (AREA)
EP89105451A 1989-03-28 1989-03-28 Panneau radiateur catalytique Ceased EP0389652A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP89105451A EP0389652A1 (fr) 1989-03-28 1989-03-28 Panneau radiateur catalytique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP89105451A EP0389652A1 (fr) 1989-03-28 1989-03-28 Panneau radiateur catalytique

Publications (1)

Publication Number Publication Date
EP0389652A1 true EP0389652A1 (fr) 1990-10-03

Family

ID=8201142

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89105451A Ceased EP0389652A1 (fr) 1989-03-28 1989-03-28 Panneau radiateur catalytique

Country Status (1)

Country Link
EP (1) EP0389652A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2694382A1 (fr) * 1992-08-03 1994-02-04 Chaussonnet Pierre Chaudière à basse température à panneaux radiants catalytiques.
DE4330130C1 (de) * 1993-09-06 1994-10-20 Fraunhofer Ges Forschung Katalytischer Brenner
EP1398587A2 (fr) * 2002-09-16 2004-03-17 EISENMANN MASCHINENBAU KG (Komplementär: EISENMANN-Stiftung) Sécheur d'objets, notamment de carrosseries de véhicules, ainsi que procédé de fonctionnement d'un tel sécheur
WO2009105907A1 (fr) * 2008-02-27 2009-09-03 Radiamon S.A. Appareil de chauffage radiant du type catalytique
US20130157203A1 (en) * 2009-11-20 2013-06-20 CC/ Thermal Technologies Inc. Gas fired catalytic heater

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3784353A (en) * 1972-01-28 1974-01-08 G Chapurin Flameless gas catalytic heater
US4154568A (en) * 1977-05-24 1979-05-15 Acurex Corporation Catalytic combustion process and apparatus
GB2080700A (en) * 1980-06-30 1982-02-10 Acurex Corp Catalytic combustion system with fiber matrix burner
GB2096483A (en) * 1981-04-09 1982-10-20 Spelman Steven Oscar Catalytic heater
DE3434415A1 (de) * 1984-09-19 1986-03-27 Siemens AG, 1000 Berlin und 8000 München Brennwertheizgeraet, insbesondere fuer niedertemperaturheizungsanlagen

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3784353A (en) * 1972-01-28 1974-01-08 G Chapurin Flameless gas catalytic heater
US4154568A (en) * 1977-05-24 1979-05-15 Acurex Corporation Catalytic combustion process and apparatus
GB2080700A (en) * 1980-06-30 1982-02-10 Acurex Corp Catalytic combustion system with fiber matrix burner
GB2096483A (en) * 1981-04-09 1982-10-20 Spelman Steven Oscar Catalytic heater
DE3434415A1 (de) * 1984-09-19 1986-03-27 Siemens AG, 1000 Berlin und 8000 München Brennwertheizgeraet, insbesondere fuer niedertemperaturheizungsanlagen

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
BWK, Band 39, Nr. 7-8, Juli/August 1987, Seiten 370-374, Düsseldorf, DE; K. LEDJEFF: "Wasserstoffnutzung durch katalytische Verbrennung" *
PATENT ABSTRACTS OF JAPAN, Band 10, Nr. 100 (M-470)[2157], 16. April 1986; & JP-A-60 233 413 (MATSUSHITA DENKI SANGYO K.K.) 20-11-1985 *
PATENT ABSTRACTS OF JAPAN, Band 6, Nr. 124 (M-141)[1002], 9 Juli 1982; & JP-A-57 49 722 (MATSUSHITA DENKI SANGYO K.K.) 23-03-1982 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2694382A1 (fr) * 1992-08-03 1994-02-04 Chaussonnet Pierre Chaudière à basse température à panneaux radiants catalytiques.
DE4330130C1 (de) * 1993-09-06 1994-10-20 Fraunhofer Ges Forschung Katalytischer Brenner
WO1995007438A1 (fr) * 1993-09-06 1995-03-16 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Bruleur catalytique
US5810577A (en) * 1993-09-06 1998-09-22 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V. Catalytic burner
EP1398587A2 (fr) * 2002-09-16 2004-03-17 EISENMANN MASCHINENBAU KG (Komplementär: EISENMANN-Stiftung) Sécheur d'objets, notamment de carrosseries de véhicules, ainsi que procédé de fonctionnement d'un tel sécheur
EP1398587A3 (fr) * 2002-09-16 2006-05-10 EISENMANN Maschinenbau GmbH & Co. KG Sécheur d'objets, notamment de carrosseries de véhicules, ainsi que procédé de fonctionnement d'un tel sécheur
WO2009105907A1 (fr) * 2008-02-27 2009-09-03 Radiamon S.A. Appareil de chauffage radiant du type catalytique
US20130157203A1 (en) * 2009-11-20 2013-06-20 CC/ Thermal Technologies Inc. Gas fired catalytic heater

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