JPH0330102B2 - - Google Patents
Info
- Publication number
- JPH0330102B2 JPH0330102B2 JP58167983A JP16798383A JPH0330102B2 JP H0330102 B2 JPH0330102 B2 JP H0330102B2 JP 58167983 A JP58167983 A JP 58167983A JP 16798383 A JP16798383 A JP 16798383A JP H0330102 B2 JPH0330102 B2 JP H0330102B2
- Authority
- JP
- Japan
- Prior art keywords
- alumina
- gas
- solid electrolyte
- concentration
- reference electrode
- 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.)
- Expired - Lifetime
Links
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 28
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims description 26
- RPMPQTVHEJVLCR-UHFFFAOYSA-N pentaaluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[Na+].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3] RPMPQTVHEJVLCR-UHFFFAOYSA-N 0.000 claims description 26
- 239000007784 solid electrolyte Substances 0.000 claims description 24
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 21
- 229910000873 Beta-alumina solid electrolyte Inorganic materials 0.000 claims description 19
- 238000005259 measurement Methods 0.000 claims description 18
- 239000000843 powder Substances 0.000 claims description 14
- 239000007772 electrode material Substances 0.000 claims description 11
- 229910052697 platinum Inorganic materials 0.000 claims description 7
- 239000004020 conductor Substances 0.000 claims description 4
- 239000011248 coating agent Substances 0.000 claims 1
- 238000000576 coating method Methods 0.000 claims 1
- 239000007789 gas Substances 0.000 description 45
- 239000011734 sodium Substances 0.000 description 16
- 238000000034 method Methods 0.000 description 15
- 238000002474 experimental method Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 7
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 5
- 230000004043 responsiveness Effects 0.000 description 5
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 4
- 229910052708 sodium Inorganic materials 0.000 description 4
- 229910000528 Na alloy Inorganic materials 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 238000003780 insertion Methods 0.000 description 3
- 230000037431 insertion Effects 0.000 description 3
- 238000000691 measurement method Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 1
- 229910001020 Au alloy Inorganic materials 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 101100066898 Mus musculus Flna gene Proteins 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052740 iodine Inorganic materials 0.000 description 1
- 239000011630 iodine Substances 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 229910001120 nichrome Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
- G01N33/0042—SO2 or SO3
-
- 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
- G01N27/4073—Composition or fabrication of the solid electrolyte
- G01N27/4074—Composition or fabrication of the solid electrolyte for detection of gases other than oxygen
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Pathology (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Molecular Biology (AREA)
- Electrochemistry (AREA)
- Combustion & Propulsion (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Measuring Oxygen Concentration In Cells (AREA)
Description
【発明の詳細な説明】
本発明は、二酸化イオウ用ガスセンサ、特に簡
便で連続測定に適し、工業的用途に使用価値の高
い二酸化イオウ用ガスセンサに関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas sensor for sulfur dioxide, and particularly to a gas sensor for sulfur dioxide that is simple, suitable for continuous measurement, and has high utility value in industrial applications.
二酸化イオウ（以下SO2と言う）ガスの濃度を
測定することは、硫化鉱を乾式処理する非鉄金属
精錬や自動車排気等より生ずるSO2ガスによる大
気汚染防止上重要な技術である。 Measuring the concentration of sulfur dioxide (hereinafter referred to as SO 2 ) gas is an important technology for preventing air pollution caused by SO 2 gas generated from non-ferrous metal smelting, which involves the dry processing of sulfide ores, and from automobile exhaust.
従来SO2ガスの濃度を測定する方法として、は
被検ガス中のSO2を吸収液に捕集して化学分析を
行なう方法（過酸化水素水法、トリン法等）、吸
光光度法で定量する方法（パラロザニン法、よう
素でんぷん法）、吸収液の電気伝導度を測定する
方法、被検ガス自体を赤外線分光計に導入して
SO2の定量を行なう方法等がある。 Conventional methods for measuring the concentration of SO 2 gas include collecting SO 2 in the sample gas in an absorption liquid and performing chemical analysis (hydrogen peroxide method, Torine method, etc.), and quantitative determination using spectrophotometry. methods (pararosanine method, iodine starch method), methods to measure the electrical conductivity of the absorption liquid, and methods to introduce the test gas itself into an infrared spectrometer.
There are methods for quantifying SO 2 .
しかし、これらの方法は操作の煩雑さ、連続測
定の困難さ、装置の複雑さ、応答性等の点から、
それらの測定方法を採用した場合、全体の効率を
低下させる要因の一つとなつている。又、近年マ
イクロコンピユータを利用した各種作業の自動化
においても、前記したような欠点を有する測定方
法、測定装置ではマイクロコンピユータ用のセン
サとしては適用しがたく、SO2ガス濃度測定が作
業上必要な産業において、その自動化の妨げとも
なつていた。 However, these methods are difficult to operate, difficult to perform continuous measurements, complex equipment, responsiveness, etc.
When these measurement methods are adopted, this is one of the factors that reduces the overall efficiency. In addition, in recent years, with the automation of various tasks using microcomputers, the measurement methods and measuring devices that have the above-mentioned drawbacks are difficult to apply as sensors for microcomputers, and SO 2 gas concentration measurement has become necessary for work. It has also become an obstacle to automation in industry.
従来、この問題点を解決する一つの方法とし
て、Na2SO4又はK2SO4等の固体電解質のペレツ
トを用い、その一面に参照極として基準となる濃
度のSO2ガスを接触させ、他の面には測定極とし
て被測定用SO2ガスを接触させ、その濃度差によ
りその両面に生ずる起電力を測定し、被測定SO2
ガスの濃度を決定する方法が提案されている。 Conventionally, one method to solve this problem is to use solid electrolyte pellets such as Na 2 SO 4 or K 2 SO 4 , contact one side with SO 2 gas at a standard concentration as a reference electrode, and The SO 2 gas to be measured is brought into contact with the surface of the SO 2 gas as a measurement electrode, and the electromotive force generated on both sides due to the concentration difference is measured.
Methods have been proposed for determining the concentration of gas.
しかし、この方法は、参照極へ絶えず基準とな
るSO2ガスをその濃度を精密に調節して供給する
ことが必要であり、SO2ガス濃度を測定するため
大規模な設備を必要とするとともに、定期的に基
準となるSO2ガス濃度をも他の測定方法でチエツ
クしなければならなかつた。 However, this method requires constantly supplying standard SO 2 gas to the reference electrode with its concentration precisely adjusted, and requires large-scale equipment to measure the SO 2 gas concentration. However, the standard SO 2 gas concentration had to be checked periodically using other measurement methods.
そこで、この種のSO2ガス濃度の測定にあた
り、操作が簡便で、連続測定が可能で装置もコン
パクトかつ精度、応答性もよく、各種自動制御用
センサとして好適なSO2ガスセンサの出現が望ま
れていた。 Therefore, in order to measure this type of SO 2 gas concentration, it is desired to develop an SO 2 gas sensor that is easy to operate, allows continuous measurement, is compact, has good accuracy and responsiveness, and is suitable as a sensor for various automatic controls. was.
本出願人は先に、このような要求を満足する
SO2ガスセンサとして、ナトリウム又はナトリウ
ム合金を含有する参照極を用いることにより、参
照極側へ基準となるSO2ガスを供給することな
く、例えば、アルゴンガスなどの不活性ガスを供
給するだけでよいガスセンサを提案した。しかし
ながら、この方法はナトリウム自体は揮発し易い
上、ナトリウムの合金でもこの傾向は変らず、例
えば、比較的に揮発し難いNa−Au系の合金で
も、900℃程度が限界であり、そのため、高温域
でセンサを使用する場合には、参照極側を密封す
るなどの工夫が必要であつた。したがつて、どう
しても、この方法の場合、製造コストが高くなる
欠点があつた。 The applicant first satisfies such requirements.
By using a reference electrode containing sodium or sodium alloy as an SO 2 gas sensor, it is only necessary to supply an inert gas such as argon gas, without supplying standard SO 2 gas to the reference electrode side. We proposed a gas sensor. However, with this method, sodium itself is easily volatilized, and this tendency does not change even with sodium alloys.For example, even with Na-Au alloys, which are relatively difficult to volatilize, the limit is around 900℃, and therefore high temperatures are required. When using the sensor in the area, it is necessary to take measures such as sealing the reference electrode side. Therefore, this method inevitably has the drawback of high manufacturing costs.
本発明者は上記実情に鑑み、高温において使用
しても差し支えなく、良好なSO2ガス濃度の測定
ができる低コストのガスセンサを得るべく種々検
討した結果、参照極材として、ある特定のものを
用いることにより、本発明の目的が達成されるこ
とを見い出し本発明を完成した。 In view of the above-mentioned circumstances, the present inventor conducted various studies in order to obtain a low-cost gas sensor that can be used at high temperatures and is capable of good measurement of SO 2 gas concentration. The present invention was completed by discovering that the object of the present invention can be achieved by using the present invention.
すなわち、本発明の要旨とするところは、固体
電解質上に設けられた参照極と測定極との間の起
電力を測定することにより測定極の二酸化イオウ
ガス濃度を測定する二酸化イオウ用固体電解質ガ
スセンサにおいて、
固体電解質がβ−アルミナ又はβ″−アルミナよ
り構成され、かつ参照極材として、β−アルミナ
とα−アルミナ又はβ″−アルミナの共存粉末を用
いることを特徴とする二酸化イオウ用固体電解質
ガスセンサにある。 That is, the gist of the present invention is to provide a solid electrolyte gas sensor for sulfur dioxide that measures the sulfur dioxide gas concentration of a measurement electrode by measuring the electromotive force between a reference electrode and a measurement electrode provided on a solid electrolyte. A solid electrolyte gas sensor for sulfur dioxide, characterized in that the solid electrolyte is composed of β-alumina or β″-alumina, and a coexisting powder of β-alumina and α-alumina or β″-alumina is used as a reference electrode material. It is in.
以下、本発明を詳細に説明する。 The present invention will be explained in detail below.
本発明で対象とするSO2ガスセンサにおいて
は、
固体電解質として、Na2O：Al2O3が１：９〜
１：11の組成を有するβ−アルミナ又はNa2O：
Al2O3が１：５〜１：７の組成を有するβ″−アル
ミナ、Na2SO4等のナトリウムを含む固体電解質
が用いられる。 In the SO 2 gas sensor targeted by the present invention, the solid electrolyte contains Na 2 O:Al 2 O 3 of 1:9 to 1:9.
β-Alumina or Na2O with a composition of 1:11:
A solid electrolyte containing sodium such as β''-alumina and Na 2 SO 4 having a composition of Al 2 O 3 of 1 :5 to 1:7 is used.
要するに、機械的強度の高さ、電気電導度の良
好さ、成形性の良好さからβ−アルミナ、β″−ア
ルミナの使用が好ましいものである。 In short, β-alumina and β″-alumina are preferably used because of their high mechanical strength, good electrical conductivity, and good formability.
また、本発明では参照極材として、β−アルミ
ナと、α−アルミナ又はβ″−アルミナの共存粉末
を用いることを必須の用件とするものである。す
なわち、β−アルミナは上述の如く、Na2Oと
Al2O3からなる複合酸化物であり、例えば、大気
中などの酸素濃度一定条件下では、Al2O3と共存
させることによりNaの活性を一定にできるので
ある。したがつて、作用効果としては、Na又は
Naの合金を含有させた参照極材と同様に働くが、
本発明の場合、大気中、1200℃程度までの高温に
おいても安定であると言う効果がある。 In addition, in the present invention, it is essential to use a coexisting powder of β-alumina and α-alumina or β″-alumina as the reference electrode material. That is, β-alumina is as described above. Na2O and
It is a complex oxide consisting of Al 2 O 3 , and under conditions of constant oxygen concentration, such as in the atmosphere, the activity of Na can be kept constant by coexisting with Al 2 O 3 . Therefore, the effect is that Na or
It works similarly to the reference electrode material containing Na alloy, but
The present invention has the advantage of being stable even in the atmosphere at high temperatures up to about 1200°C.
本発明における参照極材のβ−アルミナに対す
るα−アルミナ又はβ″−アルミナの比率は通常、
α−アルミナを用いる場合には10〜80重量％、好
ましくは20〜60重量％であり、β″−アルミナを用
いる場合は10〜90重量％、好ましくは20〜60重量
％である。α−アルミナを用いた場合にこの量が
あまり少ない場合には、相の安定度が低下しがち
であり、一方、あまり多い場合には、抵抗が大き
く電位が不安定になりがちであり、好ましくな
く、β″−アルミナを用いた場合にこの量があまり
少ない場合には、β″−アルミナの相が不安定とな
りがちであるから問題となり、一方あまり多い場
合にはβ−アルミナの相が不安定となり易く好ま
しくない。また、本発明ではβ−アルミナとα−
アルミナ又はβ″−アルミナは共存粉末であること
が、必要であり、もし、これらの混合材の場合に
は、２相が平衡状態になかつたり、平衡に達する
のに時間がかかり、Naの活量が一定せず、従つ
て、起電力値が不安定となるので好ましくない。
なお、この共存粉末の粒径は通常、0.5〜5μ程度
である。この粒径よりも粗いと詰め難くなり、細
かいと製造が困難となる。 The ratio of α-alumina or β″-alumina to β-alumina in the reference electrode material in the present invention is usually:
When α-alumina is used, it is 10 to 80% by weight, preferably 20 to 60% by weight, and when β″-alumina is used, it is 10 to 90% by weight, preferably 20 to 60% by weight.α- When using alumina, if this amount is too small, the stability of the phase tends to decrease, while if it is too large, the resistance tends to be large and the potential becomes unstable, which is not desirable. When β″-alumina is used, if this amount is too small, the β″-alumina phase tends to become unstable, which poses a problem.On the other hand, if it is too large, the β″-alumina phase becomes unstable. In addition, in the present invention, β-alumina and α-
Alumina or β″-alumina must be coexisting powders, and if these are mixed materials, the two phases may not be in an equilibrium state, or it may take time to reach equilibrium, resulting in the activation of Na. This is not preferable because the amount is not constant and therefore the electromotive force value becomes unstable.
Note that the particle size of this coexisting powder is usually about 0.5 to 5 μm. If the particle size is coarser than this, it will be difficult to pack it, and if it is finer than this, it will be difficult to manufacture.
本発明では参照極材として、適宜の導電材を加
えたものを用いるのが好ましい。この導電材の種
類としては、例えば、白金などであり、また、そ
の使用量はβ−アルミナに対して、通常、0.5〜
10重量％、好ましくは１〜３重量％である。これ
らの導電材は通常、単独の粉末状態で加えてもよ
いが、β−アルミナ又はα−アルミナなどの粉末
を調製する際に、同時に含有させてもよい。 In the present invention, it is preferable to use a material to which an appropriate conductive material is added as the reference electrode material. The type of conductive material is, for example, platinum, and the amount used is usually 0.5 to 0.5 to β-alumina.
10% by weight, preferably 1-3% by weight. These conductive materials may usually be added in the form of a single powder, but they may also be added at the same time when preparing powder such as β-alumina or α-alumina.
本発明の参照極側の構造は特に限定されるもの
ではなく、常法の構造のもので差し支えないが、
その代表的な一例につき、第１図に従い、簡単に
説明する。先ず、固体電解質であるβ−アルミナ
よりなる有底管１の外周部及び内底部には、Pt
電極２ａ，２ｂが焼付けられている。そして、そ
の有底管１の底部に本発明の参照極材であるβ−
アルミナとα−アルミナ又はβ″−アルミナの共存
粉末３が仕込まれ、その上部は前記有底管１より
も小径で、該管１内に挿入されたα−アルミナ管
４で迎えられている。また、α−アルミナ管４の
中には、有底管１の底部にあるPt電極２ｂと接
して外部に伸びるPtリード線５が設けられてい
る。 The structure of the reference pole side of the present invention is not particularly limited, and may be a conventional structure, but
A typical example will be briefly explained with reference to FIG. First, the outer periphery and inner bottom of the bottomed tube 1 made of β-alumina, which is a solid electrolyte, are coated with Pt.
Electrodes 2a and 2b are baked. Then, at the bottom of the bottomed tube 1, β-
A coexisting powder 3 of alumina and α-alumina or β″-alumina is charged, and its upper part is met by an α-alumina tube 4 inserted into the tube 1, which has a smaller diameter than the bottomed tube 1. Further, in the α-alumina tube 4, a Pt lead wire 5 is provided which contacts the Pt electrode 2b at the bottom of the bottomed tube 1 and extends to the outside.
このように構成されたセンサを用いて、SO2濃
度を測定するが、この測定は公知の方法に従つ
て、例えば外面を大気のもとSO2ガスに曝するこ
とにより、固体電解質中に起電力が発生するの
で、その外面及び内面の導電状態にある電極との
間に電圧計を設けて起電力を測定することによ
り、SO2ガス濃度を知ることができる。 The SO 2 concentration is measured using a sensor configured in this way, and this measurement is performed by exposing the outer surface to SO 2 gas in the atmosphere, for example, to measure the concentration of SO 2 generated in the solid electrolyte. Since electric power is generated, the SO 2 gas concentration can be determined by installing a voltmeter between the conductive electrodes on the outer and inner surfaces and measuring the electromotive force.
本発明のセンサの起電力は、SO2ガスがSO2＋
１／２O2＝SO3の反応をすることから、次の構成の
電池を構成していることに起因する。Pt，SO2＋
O2＋SO3／固体電解質／β−アルミナ＋α−アル
ミナ（又はβ″−アルミナ）Pt
この場合、拡散種がNaイオンなので、生ずる
起電力Ｅは次の式(1)で与えられる。 The electromotive force of the sensor of the present invention is that SO 2 gas is SO 2 +
This is because the reaction of 1/2O 2 =SO 3 occurs, and the battery has the following configuration. Pt, SO 2 +
O 2 +SO 3 /solid electrolyte/β-alumina + α-alumina (or β″-alumina) Pt In this case, since the diffusion species are Na ions, the generated electromotive force E is given by the following equation (1).
Ｅ＝RT／Ｆlna2／a1 ……(1)
ここで、a1は固体電解質の左極表面付近での
Naの活量、a2は固体電解質の右極表面付近での
Naの活量を表わす。 E=RT/Flna 2 /a 1 ...(1) Here, a 1 is near the left pole surface of the solid electrolyte.
The activity of Na, a2 , is near the right extreme surface of the solid electrolyte.
Represents the activity of Na.
温度が一定であれば、共存粉末中のナトリウム
の活量は一定であるので、右極のNaの活量a2は
一定となる。それ故、左極表面のNaの活量a1は
起電力Ｅに応じて一義的に定まる。しかも左極で
の反応2Na＋SO3＋１／２O2＝Na2SO4からSO3の濃
度は上記a1によつて決定されるので、結局、起電
力Ｅと空中の酸素濃度とに基づき反応式SO2＋
１／２O2＝SO3の平衡定数Ｋ＝PSO3／PSO2・（PO2）1/2
に
よつてSO2の濃度が定まる。即ちO2の濃度は空気
中のO2の濃度であり、ほぼ一定と考えられるの
で、起電力Ｅの値により一義的にSO2の濃度が決
定され得る。 If the temperature is constant, the activity of sodium in the coexisting powder is constant, so the activity a 2 of Na at the right pole is constant. Therefore, the activity a 1 of Na on the left pole surface is uniquely determined according to the electromotive force E. Moreover, since the reaction at the left pole is 2Na + SO 3 + 1/2O 2 = Na 2 SO 4 , the concentration of SO 3 is determined by a 1 above, so the reaction formula is SO 2+
1/2O 2 = SO 3 equilibrium constant K = PSO 3 /PSO 2・(PO 2 ) 1/2
The concentration of SO 2 is determined by: That is, since the concentration of O 2 is the concentration of O 2 in the air and is considered to be approximately constant, the concentration of SO 2 can be uniquely determined by the value of the electromotive force E.
以上詳述したごとく、本発明の二酸化イオウ用
固体電解質ガスセンサは、
固体電解質上に設けられた参照極と測定極との
間の起電力を測定することにより測定極の二酸化
イオウガス濃度を測定する二酸化イオウ用固体電
解質ガスセンサにおいて、
固体電解質がβ−アルミナ又はβ″−アルミナよ
り構成され、かつ参照極材として、β−アルミナ
と、α−アルミナ又はβ″−アルミナの共存粉末を
用いることにより、参照極にSO2ガスを用いない
のでコンパクトで、操作が簡便で、かつ連続測定
が可能で精度、応答性がよく、各種自動制御用セ
ンサとして好適なセンサとすることができる。 As detailed above, the solid electrolyte gas sensor for sulfur dioxide of the present invention measures the sulfur dioxide gas concentration at the measurement electrode by measuring the electromotive force between the reference electrode and the measurement electrode provided on the solid electrolyte. In the solid electrolyte gas sensor for sulfur, the solid electrolyte is composed of β-alumina or β″-alumina, and the reference electrode material is a coexisting powder of β-alumina and α-alumina or β″-alumina. Since SO 2 gas is not used in the electrode, the sensor is compact, easy to operate, allows continuous measurement, and has good accuracy and responsiveness, making it suitable as a sensor for various automatic controls.
実施例
［センサの作成］
α−アルミナと無水の炭酸ナトリウムをNa2O
とAl2O3の重量比で１；９になる様に混合し、次
いで、この混合粉末をマグネシア製のルツボ内に
入れ、200℃／時間の昇温速度で1450℃の温度ま
で昇温し、同温度で２時間保持することにより、
β−アルミナ粉末とβ″−アルミナの共存粉末を合
成した。Example [Creation of sensor] α-alumina and anhydrous sodium carbonate are mixed with Na 2 O
and Al 2 O 3 at a weight ratio of 1:9, then this mixed powder was placed in a magnesia crucible and heated to a temperature of 1450°C at a heating rate of 200°C/hour. , by holding at the same temperature for 2 hours,
A coexisting powder of β-alumina powder and β″-alumina was synthesized.
これをとり出し、更に、メノウ乳鉢にて粉砕し
た。次いで、上述の本発明の参照極材を利用し
て、第２図に示すようなセンサを作成した。 This was taken out and further ground in an agate mortar. Next, a sensor as shown in FIG. 2 was created using the above-described reference electrode material of the present invention.
すなわち、第２図において、１１は外径10mm、
内径７mm、長さ100mmのβ″−アルミナチユーブで
あり、その外部底面及び外側面の下から７mmまで
には白金ペーストが薄く塗られている。このβ″−
アルミナチユーブ１１の開口端部にアルミナセメ
ント１２を用いて高純度アルミナ管１３を接着
し、1000℃で約２時間乾燥させた。 That is, in Fig. 2, 11 has an outer diameter of 10 mm,
It is a β″-alumina tube with an inner diameter of 7 mm and a length of 100 mm, and a thin layer of platinum paste is applied to the outer bottom and outer surface up to 7 mm from the bottom.
A high-purity alumina tube 13 was bonded to the open end of the alumina tube 11 using alumina cement 12 and dried at 1000° C. for about 2 hours.
このβ″−アルミナチユーブ１１の中に上述の方
法で、調製したβ−アルミナとβ″−アルミナとの
共存粉末１４を仕込み、上からアルミナ製のふた
１５をした。このふた１５の中央には参照極側の
白金のリード線１６を通すために穴１５ａが穿設
されている。 A coexisting powder 14 of β-alumina and β″-alumina prepared by the method described above was charged into this β″-alumina tube 11, and a lid 15 made of alumina was placed on top. A hole 15a is bored in the center of the lid 15 for passing the platinum lead wire 16 on the reference electrode side.
上記ふた１５は、空気の導入管を兼ねたアルミ
ナ管１７を介し、ばね１８の付勢力により押さえ
つけられており、本発明の参照極材１４をβ″−ア
ルミナチユーブ１１へ密着させている。又、アル
ミナ管１７はふた１５近傍に空気の抜け穴１７ａ
を設けている。 The lid 15 is pressed down by the biasing force of a spring 18 via an alumina tube 17 that also serves as an air introduction tube, so that the reference electrode material 14 of the present invention is brought into close contact with the β''-alumina tube 11. , the alumina tube 17 has an air escape hole 17a near the lid 15.
has been established.
試料極側の白金リード線１９は螺旋状に巻いた
別の白金線２０によりチユーブ１１の外側底面に
押圧され、更にこの白金線２０は、ばね２１によ
り付勢されたアルミナ管２２によりチユーブ１１
方向へ押圧されている。 The platinum lead wire 19 on the sample pole side is pressed against the outer bottom surface of the tube 11 by another spirally wound platinum wire 20, and this platinum wire 20 is further pressed against the tube 11 by an alumina tube 22 biased by a spring 21.
being pushed in the direction.
更に上述した構成の全体はアルミナ管２３に納
められ、その上端では、被測定用SO2ガスの流出
口２４ａと白金リード線１９の挿入口２４ｂとを
備えたガラスキヤツプ、ばね１８の一端を係止し
ているアルミナリング２５及び空気の流入口２６
ａとその流出口２６ｂと白金リード線１６の挿入
口２６ｃとを備えたガラスキヤツプ２６がユニチ
ユーブ（日本理化学器機社製接合部材）によつて
順次接続されている。 Further, the entire structure described above is housed in an alumina tube 23, and at its upper end, a glass cap is provided with an outlet 24a for the SO 2 gas to be measured and an insertion port 24b for the platinum lead wire 19, and one end of the spring 18 is engaged. Stopped alumina ring 25 and air inlet 26
A, a glass cap 26 having an outlet 26b thereof, and an insertion opening 26c for the platinum lead wire 16 are sequentially connected by a unitube (a joining member manufactured by Nippon Rikagakiki Co., Ltd.).
一方、アルミナ管２３の下端では、ゴムキヤツ
プ２８が嵌入され、ばね２１の一端を係止すると
ともに、その中心孔にアルミナ管２９を貫通させ
ている。上記アルミナ管２９には熱電対３０の挿
入口３１ａと被測定用SO2ガスの流入口３１ｂと
を備えたガラスキヤツプ３１がユニチユーブ２７
により接続されている。熱電対３０はその先端を
ほぼβ″−アルミナチユーブ１１の外側底面の位置
に配置し、固体電解質としてのβ″−アルミナチユ
ーブ１１の温度を正確に捕えるよう構成されてい
る。上記のごとく構成されたものは、特にβ″−ア
ルミナチユーブ１１部分を一定温度に保持するた
め、ニクロム線抵抗炉３２の中心孔に挿入されて
いる。 On the other hand, a rubber cap 28 is fitted into the lower end of the alumina tube 23 to lock one end of the spring 21 and allow an alumina tube 29 to pass through its center hole. A glass cap 31 having an insertion port 31a for a thermocouple 30 and an inlet 31b for SO 2 gas to be measured is connected to the unit tube 27 in the alumina tube 29.
connected by. The thermocouple 30 has its tip disposed approximately at the outer bottom surface of the β''-alumina tube 11, and is configured to accurately capture the temperature of the β″-alumina tube 11 as a solid electrolyte. The device constructed as described above is inserted into the center hole of the nichrome wire resistance furnace 32 in order to particularly maintain the β″-alumina tube 11 portion at a constant temperature.
上記抵抗炉３２は上記熱電対３０により検出さ
れた温度に基づきほぼ所定温度の±１℃内に保持
される。 The resistance furnace 32 is maintained within approximately ±1° C. of a predetermined temperature based on the temperature detected by the thermocouple 30.
［測定実験］
次に上記のごとく構成したセンサを用いて、
SO2ガスの濃度測定実験を行なつた。 [Measurement experiment] Next, using the sensor configured as above,
An experiment was conducted to measure the concentration of SO 2 gas.
第２図に示した装置の系内をロータリーポンプ
で１×10-3Torrの真空に引く。この状態で炉を
100℃に加熱し水分等を蒸発させる。この後ロー
タリーポンプを止め空気を徐々に流入する。空気
が１気圧になつたら、試料極側は回路を閉じ１気
圧の空気雰囲気にする。参照極側は空気を流しバ
ブラーによつてバブリングさせて増圧にする。こ
の状態で炉を加熱させ、温度が指定の温度で安定
した後SO2ガスを流入する。 The inside of the system shown in Figure 2 is vacuumed to 1 x 10 -3 Torr using a rotary pump. In this state, open the furnace.
Heat to 100℃ to evaporate water etc. After this, the rotary pump is stopped and air is gradually introduced. When the air reaches 1 atm, close the circuit on the sample pole side to create an air atmosphere of 1 atm. Air is passed through the reference electrode side and bubbled by a bubbler to increase the pressure. The furnace is heated in this state, and after the temperature stabilizes at the specified temperature, SO 2 gas is introduced.
ガスは空気で希釈されたSO2ガスボンベを用い
た。濃度は204ppm、409ppm、613ppm、
818ppm、1022ppmである。 The gas used was an SO 2 gas cylinder diluted with air. Concentrations are 204ppm, 409ppm, 613ppm,
818ppm, 1022ppm.
炉を昇温するにあたり、回路の中を空気雰囲気
にした。また参照極側は、実験中空気を流した状
態にした。 To raise the temperature of the furnace, an air atmosphere was created inside the circuit. In addition, air was allowed to flow through the reference electrode side during the experiment.
［実験結果］
第３図〜第５図に、本発明センサの参照極を用
いた実験で得られた結果を示す。 [Experimental Results] FIGS. 3 to 5 show the results obtained in experiments using the reference electrode of the sensor of the present invention.
第３図は、横軸に時間、縦軸に起電力E.M.F.
をとり、用いたガス中のSO2濃度毎にプロツトし
た図である。SO2濃度が204ppmから1022ppmま
での５種類のガスを用いて温度1073〓にし実験を
行なつた。ガスの流量はいずれも50ml／minとし
た。最初SO2濃度を1022ppmまで、まず上げ時間
の経過と共に818ppm、613ppm、409ppm、
204ppmと濃度を下げ、再び409ppm、613ppm、
818ppm、1022ppmと濃度を上げたところ、最初
の1022ppmとあとからの1022ppmの起電力はほぼ
同一値を示し、他の濃度も最初とあとからとほぼ
同一起電力を示した。これより本発明センサは良
い再現性が得られることが判明した。 Figure 3 shows time on the horizontal axis and electromotive force EMF on the vertical axis.
This is a diagram plotting the results for each SO 2 concentration in the gas used. Experiments were conducted using five types of gases with SO 2 concentrations ranging from 204 ppm to 1022 ppm at a temperature of 1073°. The gas flow rate was 50 ml/min in both cases. Initially, the SO 2 concentration was increased to 1022ppm, and then increased to 818ppm, 613ppm, 409ppm as time progressed.
Lower the concentration to 204ppm, then 409ppm, 613ppm,
When the concentration was increased to 818ppm and 1022ppm, the electromotive force at the first 1022ppm and the later 1022ppm showed almost the same value, and the other concentrations also showed almost the same electromotive force at the beginning and later. This indicates that the sensor of the present invention provides good reproducibility.
第４図は温度1092〓で同様な実験をした結果で
ある。この実験からも本発明センサの良好な再現
性が確認できた。 Figure 4 shows the results of a similar experiment at a temperature of 1092〓. This experiment also confirmed the good reproducibility of the sensor of the present invention.
また、第５図は温度の変化に対する起電力の応
答性を示した図で、SO2濃度が1022ppmの時の結
果である。温度変化と起電力との関係は良好な直
線性を示し、また650℃以上では１回目、２回目、
３回目の各測定値はほぼ一直線上にあることが確
認できた。 Moreover, FIG. 5 is a diagram showing the responsiveness of electromotive force to changes in temperature, and shows the results when the SO 2 concentration is 1022 ppm. The relationship between temperature change and electromotive force shows good linearity, and at 650°C or higher, the first, second,
It was confirmed that the third measurement values were almost on a straight line.
第１図は本発明のセンサ構造の一例を示す説明
図、第２図は実施例の測定実験で用いたセンサの
具体的構成例を示す説明図、第３図はそのセンサ
を用い1073〓でのSO2ガス濃度の起電力を示すグ
ラフ、第４図は1092〓でのSO2ガス濃度の起電力
を示すグラフ、第５図はSO2ガス濃度が1022ppm
での雰囲気温度毎の起電力の応答性を示すグラフ
を表わす。
Fig. 1 is an explanatory diagram showing an example of the sensor structure of the present invention, Fig. 2 is an explanatory diagram showing a specific configuration example of the sensor used in the measurement experiment of the example, and Fig. 3 is an explanatory diagram showing an example of the specific configuration of the sensor used in the measurement experiment of the embodiment. Figure 4 is a graph showing the electromotive force of SO 2 gas concentration at 1092〓, Figure 5 is a graph showing the electromotive force of SO 2 gas concentration at 1022 ppm.
2 is a graph showing the responsiveness of electromotive force for each ambient temperature.
Claims (1)
の間の起電力を測定することにより測定極の二酸
化イオウガス濃度を測定する二酸化イオウ用固体
電解質ガスセンサにおいて、 固体電解質がβ−アルミナ又はβ″−アルミナよ
り構成され、かつ参照極材として、β−アルミナ
と、α−アルミナ又はβ″−アルミナの共存粉末を
用いることを特徴とする二酸化イオウ用固体電解
質ガスセンサ。 ２ 参照極材がβ−アルミナと、α−アルミナ又
はβ″−アルミナの共存粉末に導電材を加えたもの
であることを特徴とする特許請求の範囲第１項に
記載の二酸化イオウ用固体電解質ガスセンサ。 ３ 固体電解質の参照極材側の表面が、表面に白
金被膜を設けたものである特許請求の範囲第１項
又は第２項に記載の二酸化イオウ用固体電解質ガ
スセンサ。[Claims] 1. A solid electrolyte gas sensor for sulfur dioxide that measures the sulfur dioxide gas concentration at a measurement electrode by measuring the electromotive force between a reference electrode and a measurement electrode provided on a solid electrolyte, wherein the solid electrolyte is A solid electrolyte gas sensor for sulfur dioxide, characterized in that it is composed of β-alumina or β″-alumina, and uses a coexisting powder of β-alumina and α-alumina or β″-alumina as a reference electrode material. 2. The solid electrolyte for sulfur dioxide according to claim 1, wherein the reference electrode material is a coexisting powder of β-alumina, α-alumina, or β″-alumina with a conductive material added thereto. Gas sensor. 3. The solid electrolyte gas sensor for sulfur dioxide according to claim 1 or 2, wherein the surface of the solid electrolyte on the reference electrode material side is provided with a platinum coating.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58167983A JPS6058549A (en) | 1983-09-12 | 1983-09-12 | Solid electrolyte gas sensor for sulfur dioxide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58167983A JPS6058549A (en) | 1983-09-12 | 1983-09-12 | Solid electrolyte gas sensor for sulfur dioxide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6058549A JPS6058549A (en) | 1985-04-04 |
| JPH0330102B2 true JPH0330102B2 (en) | 1991-04-26 |
Family
ID=15859628
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58167983A Granted JPS6058549A (en) | 1983-09-12 | 1983-09-12 | Solid electrolyte gas sensor for sulfur dioxide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6058549A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2651931C2 (en) * | 2016-06-08 | 2018-04-24 | Общество с ограниченной ответственностью "Объединенная Компания РУСАЛ Инженерно-технологический центр" | Device and method for determination of electrolyte composition |
-
1983
- 1983-09-12 JP JP58167983A patent/JPS6058549A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6058549A (en) | 1985-04-04 |
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