WO1998013687A1 - Protection de cellule passive pour analyseur de gaz a cellule a electrolyte solide - Google Patents

Protection de cellule passive pour analyseur de gaz a cellule a electrolyte solide Download PDF

Info

Publication number
WO1998013687A1
WO1998013687A1 PCT/US1997/017066 US9717066W WO9813687A1 WO 1998013687 A1 WO1998013687 A1 WO 1998013687A1 US 9717066 W US9717066 W US 9717066W WO 9813687 A1 WO9813687 A1 WO 9813687A1
Authority
WO
WIPO (PCT)
Prior art keywords
cell
gas
protection apparatus
cell protection
solid electrolyte
Prior art date
Application number
PCT/US1997/017066
Other languages
English (en)
Inventor
Boris Y. Farber
Joanne M. Starling
Mark Little
Original Assignee
Rosemount Analytical Inc.
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 Rosemount Analytical Inc. filed Critical Rosemount Analytical Inc.
Priority to JP10515854A priority Critical patent/JP2000501512A/ja
Priority to DE19781049T priority patent/DE19781049T1/de
Priority to GB9810139A priority patent/GB2321314A/en
Publication of WO1998013687A1 publication Critical patent/WO1998013687A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4077—Means for protecting the electrolyte or the electrodes

Definitions

  • the present invention relates generally to the segment of the field of gas analysis instrumentation that involves the use of solid electrolyte cells to measure gaseous species. More specifically, the invention relates to techniques for protecting solid electrolyte cells from corrosive components in the measured gas.
  • solid electrolyte cell means a quantity of the solid electrolyte, for example zirconia-yttria ( (ZrO z ) (1 . x) (Y 2 0 3 ) x ), and porous electrical contacts or electrodes connected thereto, usually made of platinum or other suitable materials.
  • Gas analyzers having a probe with a solid electrolyte cell to measure gaseous oxygen are well known. See, for example, U.S. Pat. Nos . 3,400,054 and 3,928,161, incorporated herein by reference. Another example is the World Class 3000 Oxygen Analyzer sold by Rosemount Analytical Inc. of Orrville, Ohio, available with replacement cells under part no. 4847B61G01/02/03.
  • a common application for such analyzers is the measurement of gaseous oxygen in a flue or duct such as a smokestack.
  • the solid electrolyte cell At a given elevated temperature, the solid electrolyte cell generates an EMF V celi as a function of the concentration of oxygen (or other gaseous specie) exposed to the cell.
  • the probe is configured with a heater and thermocouple, controlled by circuitry in a separate housing, to maintain the solid electrolyte cell at a constant elevated temperature (e.g. , 750°C) .
  • a constant elevated temperature e.g. 750°C
  • solid electrolyte cells can corrode from exposure to certain gas constituents.
  • One known solution is to encapsulate an exposed electrode of the cell in a refractory overlayer. See, e.g., U.S. Pat. No. 3,645,875.
  • Another known solution is to pack platinum fibers in a passageway between the cell and the measured gas. Corrosive constituents in the measured gas chemically react with the fibers before they have an opportunity to contact the cell.
  • An object of the invention is to reduce exposure of the cell to corrosive constituents in the gas of interest in a relatively low-cost manner and without having to alter the design of the cell e.g. by applying protective coatings to the cell .
  • Other objects of the invention will become apparent from the detailed description of the invention and the accompanying drawings .
  • a solid electrolyte gas analyzer has a probe with a distal end adapted for immersion in the gas of interest.
  • a passageway in the probe connects the gas of interest to a solid electrolyte cell providing an output as a function of a constituent of the gas of interest.
  • the analyzer further includes a catalyst disposed in the passageway, the catalyst including a collection of beads each having an outer surface comprising a catalytic material such as platinum.
  • the beads are sandwiched between a first and second screen, the screens having matching concave shapes.
  • Figure 1 is a perspective view of a preferred gas analyzer.
  • Figure 2 is a sectional view of the distal end of an analyzer probe according to the invention.
  • items in the figures having the same reference symbol are the same or serve the same or a similar function.
  • Analyzer 40 comprises an analyzer probe 42 having a distal end 42A, a proximal end 42B, and a mounting flange 44 affixed therebetween to a tubular member 46.
  • Flange 44 mounts to a wall of a flue or duct such that distal end 42A projects into the flue and proximal end 42B remains outside the flue.
  • An analyzer circuit housed in a can 48, measures the cell output V cell and the cell temperature, controls the cell heater, and calculates the oxygen content of the gas of interest.
  • Can 48 preferably mounts to the probe 42 at the proximal end 42B through a standoff 52, resulting in a combined analyzer/probe having reduced installation costs compared to present day analyzers which require a separate mounting site for the analyzer circuit and an interconnecting cable. Further, corruption of the outputs from the cell and thermocouple (both mounted in distal end 42A, see FIG. 2) is minimized by keeping the length of the interconnecting wires short and shielding them with the analyzer housing comprising the tubular member 46, can 48, and standoff 52, all of which are preferably metallic.
  • Standoff 52 helps the analyzer circuit survive the high temperatures near the flue by distancing electronics can 48 from the flue. Standoff 52 also functions as a heat sink between tubular member 46 and can 48 by virtue of cooling fins or ridges 52A on its outer surfaces to dissipate heat to surrounding ambient air.
  • the wall thickness of tubular member 46 is reduced between flange 44 and standoff 52 to reduce heat conduction along the tubular member. The wall thickness can be reduced by removing material from the outside diameter of tube 46 or from the inside diameter or both.
  • Standoff 52 has a face 52B that carries pneumatic fittings 54A,54B,54C used for the introduction of a reference gas, of a calibration gas, and for a vent.
  • fittings 54A,54B,54C By placing fittings 54A,54B,54C on standoff 52, the pneumatic and electrical connections are divided between standoff 52 and electrical can 48. This separation simplifies operation and serviceability of analyzer 40 by permitting pneumatic connections to be serviced independent of the electrical connections and vice versa. Further details of the housing and analyzer circuit can be found in the co-pending applications referenced above.
  • FIG. 4 A closeup of probe distal end 42A is shown in FIG. 4, further including a dome-shaped ceramic filter 26.
  • Oxygen gas in the flue migrates through filter 26 and through a catalyst 56 before contacting a side 60A of a solid electrolyte cell 60.
  • calibration gas having a known oxygen content is provided via a pneumatic tube 58 and routed through a flange 62, displacing the flue gas and thus contacting side 60A of cell 60.
  • the opposite side 60B of cell 60 is continuously exposed to reference gas emitted from a pneumatic tube 64 and having an oxygen partial pressure P(° 2 ) REF - Cell 60 is disposed inside a cell heater 66 which heats cell 60 to a substantially constant cell temperature T.
  • Heater 66 is preferably of conventional design, formed of a length of nichrome wire helically wrapped around a quartz support cylinder.
  • C is a cell constant
  • S is a cell slope which is a function of T
  • P(0 2 ) and P(0 2 ) REF are the oxygen partial pressure at sides 60A,60B respectively of cell 60.
  • Actual solid electrolyte cells deviate from the Nernst equation to some extent.
  • a thermocouple 68 disposed proximate heater 66 and cell 60 is used for temperature control. Wires 70,72,74 extend through tubular member 46 and standoff 52 to connect cell 60, heater 66, and thermocouple 68 respectively to the analyzer circuit house
  • Catalyst 56 operates to shield cell 60 from corrosive gaseous components such as gaseous sulfur and oxides of sulfur (S0 X ) in the flue gas by catalyzing such components before they migrate to side 60A.
  • Catalyst 56 comprises a quantity of beads 56A sandwiched between stainless steel screens 56B,56C. Screens 56B,56C are preferably formed into matching concave shapes as shown to increase surface area while providing a uniform axial depth of beads 56A.
  • the screens are held in place inside a tube 57, that also holds cell 60, by spot welding or brazing.
  • the screens are preferably made of stainless steel because of its resistance to corrosion but can alternately be made of other corrosion-resistant materials.
  • Beads 56A are all preferably about 2mm diameter alumina spheres, such as part No. C5035 available from Engelhard Corp. of Seneca, South Carolina, but other suitable sizes, shapes, and compositions can also be used. Equally sized spheres are preferred because of their uniform packing characteristics, promoting a spatially uniform migration of gas throughout the volume of beads .
  • Each bead has a thin coating of catalytic material, preferably platinum. Other catalytic materials similar to platinum, such as palladium, can be used instead of platinum.
  • Catalyst 56 is held inside cell heater 66 and maintained at the cell temperature T.
  • the invention relates to solid electrolyte gas analyzers but does not encompass the solid electrolyte cell itself, which can have various configurations and compositions.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Measuring Oxygen Concentration In Cells (AREA)

Abstract

Analyseur de gaz à cellule à électrolyte solide (40), comprenant une sonde (42) destinée à être immergée dans le gaz à analyser. La sonde a un conduit (57) qui met le gaz en contact avec une cellule à électrolyte solide chauffée (60). On dispose dans le conduit (57) une série de perles (56A), ayant chacune une surface extérieure à base de matériau catalytique comme le platine. Les surfaces en platine des perles (56A) tiennent lieu de catalyseur, et sont destinées à protéger la cellule (60) contre le soufre et autres éléments corrosifs émanant du gaz analysé. Selon un mode de réalisation préféré, les perles (56A) sont disposées à proximité de la cellule (60), et un élément de chauffe (66) entoure à la fois la cellule (60) et les perles (56A), en vue de chauffer celles-ci jusqu'à une température prédéterminée.
PCT/US1997/017066 1996-09-24 1997-09-22 Protection de cellule passive pour analyseur de gaz a cellule a electrolyte solide WO1998013687A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP10515854A JP2000501512A (ja) 1996-09-24 1997-09-22 固体電解質気体分析器のための不活性セル保護装置
DE19781049T DE19781049T1 (de) 1996-09-24 1997-09-22 Passiver Zellenschutz für Trockenelektrolyt-Gasanalysator
GB9810139A GB2321314A (en) 1996-09-24 1997-09-22 Passive cell protection for solid electrolyte gas analyzer

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US2660696P 1996-09-24 1996-09-24
US60/026,606 1996-09-24

Publications (1)

Publication Number Publication Date
WO1998013687A1 true WO1998013687A1 (fr) 1998-04-02

Family

ID=21832783

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1997/017066 WO1998013687A1 (fr) 1996-09-24 1997-09-22 Protection de cellule passive pour analyseur de gaz a cellule a electrolyte solide

Country Status (4)

Country Link
JP (1) JP2000501512A (fr)
DE (1) DE19781049T1 (fr)
GB (1) GB2321314A (fr)
WO (1) WO1998013687A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004086024A1 (fr) * 2003-03-20 2004-10-07 Rosemount Analytical Inc. Analyseur d'oxygène avec étalonnage et refoulement

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11237361A (ja) * 1997-12-15 1999-08-31 Nippon Soken Inc ガスセンサ
JP2013124975A (ja) * 2011-12-15 2013-06-24 Yokogawa Electric Corp 機能性保護膜

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3928161A (en) * 1972-04-25 1975-12-23 Westinghouse Electric Corp Gas measuring probe for industrial applications
DE2748461A1 (de) * 1976-10-29 1978-05-03 Ngk Insulators Ltd Vorrichtung zur messung des sauerstoffpartialdrucks
US4132615A (en) * 1974-04-05 1979-01-02 Robert Bosch Gmbh Internal combustion engine exhaust gas oxygen sensor and catalyzer combination
US4151060A (en) * 1978-02-01 1979-04-24 Westinghouse Electric Corp. Solid state filter for gas sensors
GB2059072A (en) * 1979-09-19 1981-04-15 Degussa Solid electrolyte sensor for measuring the oxygen content in the exhaust of internal combustion engines
US4284487A (en) * 1978-10-13 1981-08-18 Milton Roy Company Oxygen analyzer probe
DE3211533A1 (de) * 1981-04-13 1982-12-02 Process Electronic Analyse Und Sauerstoffmesssonde

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3928161A (en) * 1972-04-25 1975-12-23 Westinghouse Electric Corp Gas measuring probe for industrial applications
US4132615A (en) * 1974-04-05 1979-01-02 Robert Bosch Gmbh Internal combustion engine exhaust gas oxygen sensor and catalyzer combination
DE2748461A1 (de) * 1976-10-29 1978-05-03 Ngk Insulators Ltd Vorrichtung zur messung des sauerstoffpartialdrucks
US4151060A (en) * 1978-02-01 1979-04-24 Westinghouse Electric Corp. Solid state filter for gas sensors
US4284487A (en) * 1978-10-13 1981-08-18 Milton Roy Company Oxygen analyzer probe
GB2059072A (en) * 1979-09-19 1981-04-15 Degussa Solid electrolyte sensor for measuring the oxygen content in the exhaust of internal combustion engines
DE3211533A1 (de) * 1981-04-13 1982-12-02 Process Electronic Analyse Und Sauerstoffmesssonde

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004086024A1 (fr) * 2003-03-20 2004-10-07 Rosemount Analytical Inc. Analyseur d'oxygène avec étalonnage et refoulement
US6862915B2 (en) 2003-03-20 2005-03-08 Rosemount Analytical Inc. Oxygen analyzer with enhanced calibration and blow-back

Also Published As

Publication number Publication date
GB9810139D0 (en) 1998-07-08
DE19781049T1 (de) 1998-12-10
JP2000501512A (ja) 2000-02-08
GB2321314A (en) 1998-07-22

Similar Documents

Publication Publication Date Title
US4639305A (en) Electrochemical element
US4814059A (en) Electrochemical device having a heater and leak protection electrode
US8152978B2 (en) Apparatus and method for measuring hydrogen concentration in molten metals
JPH07190863A (ja) 温度センサ
GB2046921A (en) Measuring sensor for determining the constituents of flowing gases
GB2061522A (en) Heated measuring sensor for the constituents of gases
JPS634141B2 (fr)
GB2031156A (en) Solid electrolyte sensors for determining the oxygen content of gases
GB1581519A (en) Electrochemical sensors
EP0208072B1 (fr) Détermination du silicium dans du métal fondu
EP0390337A2 (fr) Détecteur d'oxygène avec une plaque plate et un élément chauffant
JPH0342425B2 (fr)
US4462872A (en) Method of operating a gas analyzer and solid electrolyte gas sensing apparatus
CA1199366A (fr) Appareil de mesure bigaz, avec pile electrochimique a electrolyte solide
WO1998013687A1 (fr) Protection de cellule passive pour analyseur de gaz a cellule a electrolyte solide
GB892531A (en) Improvements in or relating to the detection or analysis of gases
WO1987001453A1 (fr) Capteur de flux de gaz entrant
JPH0287032A (ja) 高温用サーミスタ
JPH11190719A (ja) ガスセンサ装置
US5521098A (en) Thermionic ionization detector with flow-through thermionic source
US20070045113A1 (en) Solid electrolyte gas sensor
JP3649544B2 (ja) ガス分析装置
CZ179297A3 (cs) Zařízení pro provádění elektrochemických měření ve skleněných taveninách nebo v taveninách solí
US20060254908A1 (en) Electrochemical solid electrolyte sensor for the detection of oxygen, hydrocarbons and moisture in vacuum environments
JPH0763620A (ja) 溶湯測定器具および該器具を用いた測定装置

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): DE GB JP

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE

ENP Entry into the national phase

Ref document number: 1998 515854

Country of ref document: JP

Kind code of ref document: A

121 Ep: the epo has been informed by wipo that ep was designated in this application
RET De translation (de og part 6b)

Ref document number: 19781049

Country of ref document: DE

Date of ref document: 19981210

WWE Wipo information: entry into national phase

Ref document number: 19781049

Country of ref document: DE

122 Ep: pct application non-entry in european phase