KR940009952B1 - Measuring method of gas density - Google Patents

Measuring method of gas density Download PDF

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KR940009952B1
KR940009952B1 KR1019900022632A KR900022632A KR940009952B1 KR 940009952 B1 KR940009952 B1 KR 940009952B1 KR 1019900022632 A KR1019900022632 A KR 1019900022632A KR 900022632 A KR900022632 A KR 900022632A KR 940009952 B1 KR940009952 B1 KR 940009952B1
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equilibrium
gas
solid
oxide
gas density
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KR920012910A (en
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정원섭
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포항종합제철 주식회사
정명식
재단법인 산업과학기술연구소
백덕현
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    • 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
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid

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Abstract

The method detects the equivalence of a measuring system by electromotive force in the equivalence gas density of a solid oxidation material. The method adjusts the gas density in order to maintain 0mV in the CO-CO2 compound gases, and exactly measures the equivalence gas density. The material includes the solid electro-analysis matarial which is ZrO2(Y2O3),and the cell which is Pt/CO-CO2/ ZrO2(Y2O3)/M.MO/Pt. The method includes the CO-CO2 compound gases which are adjusted to make electro-motive force 0mV, and the equivalence gas density which measures the temperature at the electro-motive force, 0mV.

Description

고체산화물의 평형가스 농도 측정방법Method of measuring equilibrium gas concentration of solid oxide

제 1 도는 종래의 기전력법으로 고체 산화물의 평형가스 농도를 측정환 결과를 나타내는 그래프.1 is a graph showing a measurement result of the equilibrium gas concentration of a solid oxide by a conventional electromotive force method.

제 2 도는 고체 산화철의 환원 평형가스 조성을 본 발명법에 의해 측정한 결과와 종래법에 의해 측정된 신뢰성있는 결과를 나타내는 그래프.2 is a graph showing the results of measuring the reduced equilibrium gas composition of solid iron oxide by the present invention and the reliable results measured by the conventional method.

제 3 도는 칼슘 페라이트의 환원 평형가스 조성을 본 발명법 및 종래법에 의해 측정된 결과를 나타내는 그래프.3 is a graph showing the results of the reduction equilibrium gas composition of calcium ferrite measured by the present invention and conventional methods.

본 발명은 고체 전해질을 사용하여 고체 산화물의 평형가스 농도를 측정하는 방법에 관한 것으로서, 보다 상세하게는, 이트리아 안정화 지르코니아를 고체 전해질로 사용하며, 표준계로서 CO-CO2혼합가스를 사용하고, 고체 산화물을 측정계로 하여 구성되는 셀(Cell)구조에 의해 고체 산화물의 평형가스 농도를 측정하는 방법에 관한 것이다.The present invention relates to a method for measuring the equilibrium gas concentration of a solid oxide using a solid electrolyte, more specifically, using yttria stabilized zirconia as a solid electrolyte, using a CO-CO 2 mixed gas as a standard system The present invention relates to a method for measuring the equilibrium gas concentration of a solid oxide by a cell structure composed of the solid oxide as a measuring system.

일반적으로, 고체 산화물의 평형론적인 산소 분압측정을 위한 방법으로는 화학분석법, 열천평법, 기전력법등이 있다.In general, methods for the equilibrium oxygen partial pressure measurement of solid oxides include chemical analysis, thermobalance, electromotive force, and the like.

상기 화학분석법에는 정적법, 가스 순환법, 유도법등이 있는데, 정적법은 반응관중에 시로 및 반응가스를 충만시킨후 일정온도로 유지시켜 평형에 도달했을때의 가스조정을 분석하는 방법이고, 가스 순환법은 반응가스를 순환시켜 평형에 도달하는 시간을 단축시키고 열분리 효과도 얻는 방법이고, 유동법은 가열된 고체 산화물상 위로 가스를 연속적으로 틀려보내면서 평형가스 조성을 구하는 방법이다. 그러나 정적법, 가스 순환법, 우동법등의 화학분석법은 고체 산화물과 반응가스가 평형에 도달했는지를 판단하는 것이 어렵고 반응가스의 조정, 농도 분석의 정도등에 측정정도가 의존된다.The chemical analysis method includes a static method, a gas circulation method, an induction method, etc. The static method is a method of analyzing gas adjustment when equilibrium is reached by maintaining a constant temperature after filling a reactor with a siro and a reaction gas. The circulation method is a method of shortening the time to reach the equilibrium by circulating the reaction gas and obtaining a thermal separation effect, and the flow method is a method of obtaining the equilibrium gas composition while continuously sending the gas over the heated solid oxide phase. However, chemical analysis methods such as static methods, gas circulation methods, and udon methods make it difficult to determine whether the solid oxide and the reaction gas have reached equilibrium, and the measurement accuracy depends on the adjustment of the reaction gas and the degree of concentration analysis.

상기 열천평법은 열천평을 이용하여 일정온도에서 반응가스(CO-CO2또는 H2-H2O)를 전기로 중에 흘려보내면서 산화물과 반응시켜 중량의 변화를 측정하여 평형점수를 구하는 방법으로, 이 방법도 화학분석법과 마찬가지로 측정 정도는 반응가스의 조성, 가스 농도분석의 정도, 열천평의 감도등에 의존하고, 특히 저온에서는 반응속도가 느려서 충분히 평형에 도달했는지의 여부를 판단하기 어렵기 때문에 평형분압을 정확히 측정하는 것이 어렵다.The thermo-balance method is a method of obtaining the equilibrium score by measuring the change in weight by reacting with the oxide while flowing the reaction gas (CO-CO 2 or H 2 -H 2 O) in an electric furnace at a constant temperature using a thermal balance This method, like the chemical analysis method, depends on the composition of the reaction gas, the degree of gas concentration analysis, the sensitivity of the thermal balance, and especially at low temperatures, it is difficult to judge whether the equilibrium has been sufficiently reached. Because of this, it is difficult to accurately measure the equilibrium partial pressure.

상기 기전력법은 고체중으로 전류가 흐를때 그 전하의 이동이 대부분 이온에 의해서 이루어지는 것을 고체 전해질이라고 하는데, 이 고체 전해질 가스 센서는 측정하고자 하는 가스나 고체중에 포함되어 있는 검출하고 싶은 화학성분은 반응물질로 하는 고체 전해질 전지를 만들어 그 전지의 기전력 또는 전류의 크기로부터 목적으로 하는 화학성분의 농도를 알고자 하는 방법이다.The electromotive force method is called a solid electrolyte, in which the movement of electric charges is mostly caused by ions when an electric current flows in a solid. The solid electrolyte gas sensor is a gas to be measured or a chemical component to be contained in a solid is a reactant It is a method to make a solid electrolyte battery, and to know the concentration of a desired chemical component from the magnitude of the electromotive force or current of the battery.

일반적으로 고체 전해질을 이용하는 기전력법이 화학분석법, 열천평법등 보다 측정전도가 우수하다고 생각되고 있지만, ZrO2(CaO),ZrO2(MgO)등의 고체 전해질을 사용하는 기전력법도 낮은 온도에서는 산소이온의 수율(輸率)이 1보다 작게 되어 측정오차가 발생할 가능성이 있다. 여기서 산소이온의 수율이라고 하는 것은 산화물 고체 전해질중을 이동하는 전하의 담당으로서 산소 음이온, 과잉전자 또는 정공(vacancy)이 있는데, 산소 음이온 전도도를 이 셋의 전도도 합으로 나눈 값을 의미한다.In general, electromotive methods using solid electrolytes are considered to have better measurement conductivity than chemical analysis and thermogravimetric methods, but electromotive methods using solid electrolytes such as ZrO 2 (CaO) and ZrO 2 (MgO) are also used at low temperatures. The yield of ions becomes smaller than 1, which may cause measurement errors. Here, the yield of oxygen ions is responsible for the charges that move in the oxide solid electrolyte, and there are oxygen anions, excess electrons, or vacancy, which means the oxygen anion conductivity divided by the sum of these three conductivity.

그리고, 기전력법으로 산화물의 산소 포텐셔(Potential)을 측정하여 그 결과로부터 CO-CO2혼합가스와의 평형가스 조성을 구하기 위해서는 CO+(1/2)O2=CO2반응의 표준 자유 에너지의 변화값이 필요하게 되는데, 이 값은 기존 연구자들의 연구결과가 상당히 다르게 보고되어 있어서 어떤 값을 사용하느냐에 따라서 결과가 다르게 되는 믄제점이 있다. 이와같은 현상을 제 1 도에 나타내었는데. 제 1 도중의 점선의 결과가 CO+(1/2)O2=CO2반응의 표준 자유 에너지변화값을 극단적으로 잘못 선택했을 경우를 나타낸다. 이 경우는 금속철(Fe), Magnetite(Fe3O4),Wustite(FexO)가 만나는 삼중점이 서로 만나지 않을 뿐만 아니라 신뢰성있는 결과와 많은 차이가 나타나고 있음을 알 수 있다. 또한, 지르코니아 고체 전해질을 사용하여 다음과 같은 셀(Cell)을 구성하는 경우, 기전력, 온도와 산소 포텐셜(Potential)과의 관계는 다음과 같다.In order to obtain the equilibrium gas composition with the CO-CO 2 mixed gas by measuring the oxygen potential of the oxide by electromotive force, the change of the standard free energy of the reaction CO + (1/2) O 2 = CO 2 There is a problem that the value is required, which is different from the previous researcher's research results, depending on which value is used. This phenomenon is shown in FIG. The result of the dashed line in the first direction shows the case where the standard free energy change value of the CO + (1/2) O 2 = CO 2 reaction is extremely wrongly selected. In this case, it can be seen that the triple points where the metal iron (Fe), magnetite (Fe 3 O 4 ), andustite (FexO) meet not only meet each other, but also have reliable results and many differences. In addition, when a zirconia solid electrolyte is used to form a cell as follows, the relationship between electromotive force, temperature, and oxygen potential is as follows.

Pt/Po2(ref.)/Zro2(CaO)/PO2(meas.)/PtPt / Po 2 (ref.) / Zro 2 (CaO) / PO 2 (meas.) / Pt

여기서 Po2(ref.), PO2(meas.)는 각각 표준계(전극)과 측정계(전극)의 산소분압, P-는 전자전동 매개변수(Parameter)값을 나타낸다. 종래에는 산화물의 평형가스 농도를 측정하기 위하여 표준계로 공기, Ni,NiO 혼합물이나 Fe, FeO 혼합물등을 사용한다. 상기 P-값은 일반적으로 작은 값으로 알려져 있는데, 예를 들면 표준전극에 공기를 사용하였을 경우 Po2(ref.)1/4〉〉P-1/4가 되어 윗식 좌변문자의 P-는 무시가능하다.Where Po 2 (ref.) And PO 2 (meas.) Are the oxygen partial pressures of the standard system (electrode) and the measurement system (electrode), respectively, and P- represents the electromotor parameter value. Conventionally, air, Ni, NiO mixtures, Fe, FeO mixtures, and the like are used as standard systems to measure the equilibrium gas concentration of oxides. The P-value is generally known as a small value. For example, when air is used as the standard electrode, the value of P 2 is reduced to Po 2 (ref.) 1/4 〉> P− 1/4 . It is possible.

그러나, 측정계의 Po2가 P-와 비슷한 정도의 값을 가지면 P-값을 정확히 모르는 상태에서는 측정계 산화물의 산소 포텐셜을 구하는 것은 문제가 있고, 이 값을 무시해서는 않된다.However, if Po 2 of the measuring system has a value similar to P-, it is problematic to find the oxygen potential of the measuring system oxide in a state where the P-value is not known accurately, and this value should not be ignored.

따라서, 본 발명은 저온에서도 비교적 산소이온의 수율이 큰 이트리아 안정화 지르코니아[ZrO2(Y2O3)]를 고체 전해질로 사용하여 표준계에 CO-CO2혼합가스를 흘러보내면서 산화물의 평형 CO-CO2혼합가스의 조성을 구하는 방법을 제공하고자 하는데 그 목적이 있다.Therefore, in the present invention, the equilibrium of the oxides is flowed through a CO-CO 2 mixed gas in a standard system by using yttria stabilized zirconia [ZrO 2 (Y 2 O 3 )], which has a relatively high yield of oxygen ions even at low temperatures, as a solid electrolyte. Its purpose is to provide a method for obtaining the composition of a CO-CO 2 mixed gas.

이하, 본 발명을 설명한다.Hereinafter, the present invention will be described.

본 발명은 기전력법에 의해 고체 산화물의 평형가스 농도를 측정하는 방법에 있어서, 이트리아 안정화 지르코니아[ZrO2(Y2O3)]를 고체 전해질로 사용하고, CO-CO2혼합가스를 표준계로하고, 고체 산화물을 측정계로 하여 Pt/CO-CO2/ZrO2(Y2O3)/M.MO/Pt와 같은 셀(Cell)을 구성하고, 상기 표준계에 CO-CO2혼합가스를 흘려보내어 기전력이 0(Zero)mV가 될때까지 CO-CO2혼합가스를 조성 조절하고, 기전력의 0mV가 되는 가스 조성을 그 온도에서의 산화물의 평형가스 조성으로 하여 고체 산화물의 평형가스 농도를 측정하는 방법에 관한 것이다.The present invention is a method for measuring the equilibrium gas concentration of a solid oxide by electromotive force method, using yttria stabilized zirconia [ZrO 2 (Y 2 O 3 )] as a solid electrolyte, CO-CO 2 mixed gas as a standard system Using a solid oxide as a measuring system, a cell such as Pt / CO-CO 2 / ZrO 2 (Y 2 O 3 ) /M.MO/Pt was formed, and a CO-CO 2 mixed gas was added to the standard system. The CO-CO 2 mixed gas is controlled until the electromotive force reaches 0 (zero) mV, and the equilibrium gas composition of the solid oxide is measured by setting the gas composition which becomes 0 mV of the electromotive force as the equilibrium gas composition of the oxide at that temperature. It is about a method.

본 발명에 있어서, CO-CO2혼합가스를 표준계로 하는 셀을 이용하여CO /CO2비를 조성하여 기전력이 0mv가 되도록 하기 때문에 상기 식(1)의 전자전도 매개변수(P-)의 영향을 고려하지 않아도 되어 산화물의 정확한 산소 포텐셜을 측정할 수 있다.In the present invention, the effect of the electron conductivity parameter (P-) of the above formula (1) is achieved by forming a CO / CO 2 ratio by using a cell having a CO-CO 2 mixed gas as a standard system so that the electromotive force is 0mv. It is not necessary to take into account the exact oxygen potential of the oxide.

이하, 실시예를 통하여 본 발명을 상세히 설명한다.Hereinafter, the present invention will be described in detail through examples.

[실시예 1]Example 1

고체 산화철의 환원 평형가스 조성을 다음과 같은 본 발명의 고체 전해질 셀을 사용하여 측정하고 그 결과를 X-선 분석법 및 산화 및 환원법에 의해 측정된 결과와 함께 제 2 도에 나타내었다.The reduced equilibrium gas composition of the solid iron oxide was measured using the solid electrolyte cell of the present invention as follows and the results are shown in FIG. 2 together with the results measured by X-ray analysis and oxidation and reduction methods.

Pt/CO-CO2/ZrO2(Y2O3)/Fe.FexO or FexO, Fe3O4/Pt 제 2 도에 나타난 바와 같이, 본 발명법에 의해 측정된 결과와 과거에 발표된 신회성 있는 결과를 비교해 볼때, 본 발명에 의한 측정 방법은 각종 고체 산화물의 평형론적인 측정방법으로서 가치가 있음을 알 수 있다.Pt / CO-CO 2 / ZrO 2 (Y 2 O 3 ) /Fe.FexO or FexO, Fe 3 O 4 / Pt As shown in FIG. 2, the results measured by the inventive method and previously published Comparing the ashy results, it can be seen that the measuring method according to the present invention is valuable as an equilibrium measuring method for various solid oxides.

[실시예 2]Example 2

다음과 같은 본 발명의 고체 전해질 셀을 사용하여 칼슘페라이트의 CO, CO2혼합가스에 의한 환원 평형가스 조성을 측정하고 그 결과를 열천평법에 측정된 결과와 슈만(Schurmann et al)등에 의해 보고된 결과와 함께 제 3 도에 나타내었다.Using the solid electrolyte cell of the present invention as follows, the reduction equilibrium gas composition of the CO and CO 2 mixed gas of calcium ferrite was measured and the results were measured by thermogravimetric method and reported by Schurmann et al. It is shown in FIG. 3 with the result.

Pt/CO-CO2/ZrO2(Y2O3)/CaO, Fe, C2F/PtPt / CO-CO 2 / ZrO 2 (Y 2 O 3 ) / CaO, Fe, C 2 F / Pt

Pt/CO-CO2/ZrO2(Y2O3)/ Fe, 'FeO', C2F/PtPt / CO-CO 2 / ZrO 2 (Y 2 O 3 ) / Fe, 'FeO', C 2 F / Pt

Pt/CO-CO2/ZrO2(Y2O3)/ Fe, C2F, CW3F/PtPt / CO-CO 2 / ZrO 2 (Y 2 O 3 ) / Fe, C 2 F, CW 3 F / Pt

Pt/CO-CO2/ZrO2(Y2O3)/CW3F,'FeO', C2F/PtPt / CO-CO 2 / ZrO 2 (Y 2 O 3 ) / CW 3 F , 'FeO', C 2 F / Pt

Pt/CO-CO2/ZrO2(Y2O3)/CWF, CW3F, C2F/PtPt / CO-CO 2 / ZrO 2 (Y 2 O 3 ) / CWF, CW 3 F, C 2 F / Pt

제 3 도에 나타난 바와 같이, 본 발명에 의해 측정된 결과와 열전평법에 측정된 결과와 슈만등에 의해 보고된 결과가 상당히 다르게 나타나고 있음을 알 수 있다.As shown in FIG. 3, it can be seen that the results measured by the present invention, the results measured by the thermogravimetric method, and the results reported by Schumann et al. Appear quite different.

상술한 바와 같이, 본 발명이 고체 산화물의 평형가스 농도 측정방법은 표준계와 측정하고자 하는 측정계사이에 평형이 이루어졌는지 여부를 기전력에 의해 판단할 수 있으며, 표준계도 CO-CO2혼합가스를 사용하여 기전력을 0mV가 되도록 가스 조성을 조절하면서 측정하므로 전자 전도 매개변수의 영향을 고려하지 않아도 되므로 정확한 평형가스 조성을 측정할 수 있는 효과가 있는 것이다.As described above, in the present invention, the method for measuring the equilibrium gas concentration of a solid oxide may be determined by electromotive force whether equilibrium is achieved between a standard system and a measurement system to be measured, and the standard system uses a CO-CO 2 mixed gas. Therefore, the electromotive force is measured while adjusting the gas composition to be 0mV, so it is not necessary to consider the influence of the electron conduction parameters, so that an accurate equilibrium gas composition can be measured.

Claims (1)

기전력법에 의해 고체 산화물의 평형가스 농도를 측정하는 방법에 있어서, 이트리아 안정화 지르코니아[ZrO2(Y2O3)]를 고체 전해질로 사용하고, CO-CO2혼합가스를 표준계로 하고, 고체 산화물을 측정계로 하여 Pt/CO-CO2/ZrO2(Y2O3)/M.MO/Pt와 같은 셀(Cell)을 구성하고, 상기 표준계에 CO-CO2혼합가스를 흘러보내어 지전력이 0(Zero)mV가 될때까지 CO-CO2혼합가스 조성을 조절하고, 기전력이 0mV가 되는 가스 조성을 그 온도에서의 산화물의 평형가스 조성으로 하여 측정하는 것을 특징으로 하는 고체 산화물의 평형가스 농도 측정방법.In the method for measuring the equilibrium gas concentration of a solid oxide by the electromotive force method, yttria stabilized zirconia [ZrO 2 (Y 2 O 3 )] is used as a solid electrolyte, and a CO-CO 2 mixed gas is used as a standard system, Using a oxide as a measuring system, a cell such as Pt / CO-CO 2 / ZrO 2 (Y 2 O 3 ) /M.MO/Pt is formed, and a CO-CO 2 mixed gas flows through the standard system. Equilibrium gas concentration of solid oxide, characterized in that the CO-CO 2 mixed gas composition is adjusted until the power is 0 (zero) mV, and the gas composition at which the electromotive force is 0 mV is measured as the equilibrium gas composition of the oxide at that temperature. How to measure.
KR1019900022632A 1990-12-31 1990-12-31 Measuring method of gas density KR940009952B1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100740526B1 (en) * 2004-10-07 2007-07-18 김봉희 Box for handling glass substrates

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