JP2018179596A - Method for measuring sulfur dioxide gas and measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method with which it is possible to continuously observe the state of presence of a sulfur dioxide gas, and a device therefor.SOLUTION: There is provided a method for measuring a SOgas characterized by including the steps of: determining a correlation between a ratio of PbOquantity to a total quantity of PbOquantity and PbSOquantity and electrical resistance; creating an SOevaluation test piece containing PbOon the basis of the determined correlation; installing the SOevaluation test piece in an environment of measurement object and measuring the electrical resistance of the SOevaluation test piece in the environment; and finding, from the measurement result of electrical resistance of the SOevaluation test piece in the environment, an SOabsorption quantity of the SOevaluation test piece in the environment on the basis of the correlation between the ratio of PbOquantity and the electrical resistance.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method of measuring sulfur dioxide gas present in an atmosphere and an apparatus using the method.

As a method of evaluating sulfur dioxide gas, a cylindrical method based on JIS Z 2382: 1998, that is, a cylinder of exposed lead dioxide (PbO ₂ ) is periodically recovered and accumulated lead sulfate (PbSO ₄ ) There is a method to evaluate by analyzing quantitatively chemically.

In Patent Document 1, after a predetermined metal is exposed to the air environment, the change in contact resistance before and after the exposure of the metal is measured to determine the relationship between the amount of airborne salt or the amount of sulfur oxides and the amount of contact resistance change measured in advance. Thus, a method of quantitatively measuring those environmental factors is disclosed. Specifically, use a metal material formed of an alloy of one kind of pure metal or two or more kinds of metal elements of any of the following group A (for sulfur oxide amount) or B group (for airborne salt amount) Is disclosed.
Group A: Ni, Cr, Co, Cu, Zn, Ag
Group B: Fe, Al, Zr, Nb, Mo, Ta

Patent documents 2 and 3 are methods of predicting the thickness change amount of steel materials used in the atmosphere environment by using Y = AX ^B (where Y: thickness change amount of steel materials, X: elapsed years). It is disclosed. However, the thickness variation that can be predicted by the methods disclosed in Patent Literatures 2 and 3 is yearly, and it is extremely difficult to measure the degree of daily variation.

JP, 2009-250845, A Patent No. 5167080 Patent No. 5066160 gazette

  However, in the cylindrical method described above, only the final accumulation amount of lead sulfate after the exposure period of the cylindrical method can be evaluated, and lead sulfate during the exposure period can not be continuously evaluated. It is not possible to continuously monitor the presence of sulfur dioxide gas.

  In Patent Document 1, Pb is exemplified as having the same action as the metal element of the group A. However, in patent document 1, it is based on forming films, such as a sulfide, in a metal surface, and measuring the change of the contact resistance before and behind exposure of the said metal surface. However, in Patent Document 1, when measuring the amount of change in contact resistance per unit area of the metal material after exposure, the amount of change in contact resistance is measured after recovering the metal material after exposure. It is impossible to continuously measure the state of existence of sulfur dioxide gas which changes with time.

  The thickness variation that can be predicted by the methods disclosed in Patent Literatures 2 and 3 is yearly, and it is extremely difficult to observe daily variation.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a method and apparatus capable of continuously measuring the state of existence of sulfur dioxide gas which changes with time.

In order to solve the above problems, the present inventors have found that the use of PbO ₂ can continuously measure the state of existence of sulfur dioxide gas which changes with time without particularly limiting the shape. The invention is summarized below. Incidentally, the test specimens to evaluate the existing state of the sulfur dioxide (SO ₂₎ gas with PbO _2, referred to herein as SO ₂ evaluation test body.

（３）更に、ＪＩＳ Ｚ ２３８２：１９９８に基づく円筒法を用いて、前記測定対象の環境の平均のＳＯ_２付着度（単位：mg/dm²/day）を測定する工程と、
前記円筒法の曝露期間と同一の期間における前記ＳＯ_２評価試験体のＳＯ_２吸収量の経時変化及び１日当たりの平均のＳＯ_２吸収量を測定する工程と、
前記平均のＳＯ_２付着度と、前記１日当たりの平均のＳＯ_２吸収量との関係を求める工程と、
前記平均のＳＯ_２付着度と、前記１日当たりの平均のＳＯ_２吸収量との関係に基づいて、前記ＳＯ_２評価試験体のＳＯ_２吸収量の経時変化を前記円筒法によるＳＯ_２付着度の経時変化としてモニタリングする工程を含むことを特徴とする、（１）又は（２）に記載のＳＯ_２ガスの計測方法。
（４）ＰｂＯ_２を含有し、少なくともＰｂＯ_２の一部を環境中に曝露し、環境中におけるＳＯ_２ガスを吸収するＳＯ_２評価試験体を用いて環境中におけるＳＯ_２ガスを計測するＳＯ_２ガスの計測装置であって、
前記ＳＯ_２評価試験体に含まれるＰｂＯ_２量及びＰｂＳＯ_４量の合計量に対する前記ＰｂＯ_２量の割合と、前記ＳＯ_２評価試験体の電気抵抗との相関関係に基づいて作成されたＳＯ_２評価試験体と、
測定対象の環境中における前記ＳＯ_２評価試験体の電気抵抗を測定する電気抵抗測定装置と、
前記相関関係を記憶する相関関係保持装置と、
前記相関関係に基づいて、前記ＳＯ_２評価試験体の電気抵抗の測定結果から、前記環境中における前記ＳＯ_２評価試験体のＳＯ_２吸収量を求める試験体含有率導出装置と、を含むことを特徴とするＳＯ_２ガスの計測装置。
（５）更に、電気抵抗が既知であり、前記ＳＯ_２評価試験体と直列に接続される基準抵抗と、
前記基準抵抗の電気抵抗を測定する基準抵抗用抵抗測定機とを備え、
前記電気抵抗測定装置は、前記直接に接続されたＳＯ_２評価試験体及び基準抵抗からなる直列抵抗体に印加される電圧Ｅと前記基準抵抗に印加される電圧Ｅｒを測定し、前記基準抵抗の電気抵抗Ｒｒと以下の式により前記ＳＯ_２評価試験体の電気抵抗Ｒｓを求める機能を更に有することを特徴とする（４）に記載のＯ_２ガスの計測装置。

（６）ＪＩＳ Ｚ ２３８２：１９９８に基づく円筒法の曝露期間と同一の期間における前記ＳＯ_２評価試験体のＳＯ_２吸収量の経時変化及び１日当たりの平均のＳＯ_２吸収量を測定するＳＯ_２吸収量の経時変化を測定する機能と、
前記円筒法により得られた前記測定対象の環境における平均のＳＯ_２付着度（単位：mg/dm²/day）と、前記１日当たりの平均のＳＯ_２吸収量とを比較し、前記ＳＯ_２評価試験体のＳＯ_２吸収量の経時変化を前記円筒法によるＳＯ_２付着度の経時変化を求める機能とを有することを特徴とする、（４）又は（５）に記載のＳＯ_２ガスの計測装置。 (1) containing PbO _2, SO ₂ for measuring the SO ₂ gas in at least part of the PbO ₂ was exposed to the environment, environment with SO ₂ evaluation test body to absorb SO ₂ gas in the environment How to measure gas,
And determining the ratio of the PbO ₂ weight relative to the total amount of the PbO ₂ amount contained in the SO ₂ evaluation test body and PbSO ₄ amount, the correlation between the electrical resistance of the SO ₂ evaluation test body,
Placing the SO ₂ evaluation test body in an environment to be measured, and measuring the electrical resistance of the SO ₂ evaluation test body in the environment;
On the basis of the correlation, the SO ₂ to the measurement results of the electrical resistance of SO ₂ evaluation test body, characterized in that it comprises a step of determining the SO ₂ absorption amount of the SO ₂ evaluation test body in the environment How to measure gas.
(2) A reference resistor whose electric resistance is known and an SO ₂ evaluation test body are connected in series to constitute a series resistor, and a voltage E applied to the series resistor and a voltage applied to the reference resistor The method of measuring O ₂ gas according to (1), further comprising the step of measuring Er, and determining the electric resistance Rs of the SO ₂ evaluation test body by the electric resistance Rr of the reference resistance and the following equation. .

(3) Furthermore, using the cylindrical method based on JIS Z 2382: 1998, measuring the average SO ₂ adhesion degree (unit: mg / dm ² / day) of the environment to be measured,
Measuring a SO ₂ absorption amount of aging and 1 day average SO ₂ absorption amount of the SO ₂ evaluation test body in the same period and the exposure period of the cylinder method,
Determining a relationship between the average SO ₂ deposition rate and the average daily SO ₂ absorption amount;
And said average of SO ₂ degree of adhesion, on the basis of the relationship between the average of the SO ₂ absorption amount of the daily, the time course of SO ₂ absorption amount of the SO ₂ evaluation test of SO ₂ attaching degree by the cylinder method The method for measuring SO ₂ gas according to (1) or (2), comprising the step of monitoring as a change over time.
(4) containing PbO _2, SO ₂ for measuring the SO ₂ gas in at least part of the PbO ₂ was exposed to the environment, environment with SO ₂ evaluation test body to absorb SO ₂ gas in the environment A gas measuring device,
The ratio of the PbO ₂ weight relative to the total amount of the SO ₂ Rating PbO ₂ amount contained in the specimen and PbSO ₄ amount, SO ₂ Evaluation created based on the correlation between the electrical resistance of the SO ₂ evaluation test body Test body,
An electrical resistance measuring device for measuring the electrical resistance of the SO ₂ evaluation specimen in the environment to be measured,
A correlation holding device for storing the correlation;
On the basis of the correlation, from the SO ₂ Evaluation of the electrical resistance of the specimen measurement results, to include a specimen content deriving device for obtaining the SO ₂ absorption amount of the SO ₂ evaluation test body in the environment Measurement equipment of SO ₂ gas which is characterized.
(5) Furthermore, a reference resistance whose electric resistance is known and which is connected in series with the SO ₂ evaluation test body,
And a resistance measuring device for reference resistance which measures the electric resistance of the reference resistance,
The electrical resistance measuring device measures a voltage E applied to a series resistor consisting of the directly connected SO ₂ evaluation test body and a reference resistance and a voltage Er applied to the reference resistance, and The apparatus for measuring O ₂ gas according to (4), further having a function of determining the electric resistance Rs of the SO ₂ evaluation test body by the electric resistance Rr and the following equation.

(6) JIS Z 2382: SO 2 measuring the SO ₂ absorption amount of aging and 1 day average SO ₂ absorption amount of the SO ₂ evaluation test body in the same period and the exposure period of the cylinder method based on 1998 absorption With the ability to measure changes in volume over time,
The SO ₂ evaluation was made by comparing the average SO ₂ attachment degree (unit: mg / dm ² / day) in the environment of the measurement target obtained by the cylindrical method with the average SO ₂ absorption amount per day The apparatus for measuring SO ₂ gas according to (4) or (5), characterized in that it has a function of determining the time-dependent change of the SO ₂ deposition degree by the cylindrical method with the time-dependent change of the SO ₂ absorption amount of the test body. .

  According to the present invention, it is possible to continuously measure the presence of sulfur dioxide gas which changes with time.

It is a flow chart of a first embodiment of a method for measuring the SO ₂ gas of the present invention. It is a schematic block diagram of the measuring device 1 which enforces the measuring method of FIG. 1A. It is a schematic block diagram of the electrical resistance measuring device 3 of the measuring device 1 of FIG. 1B. (A) is a schematic top view of a SO ₂ evaluating test body 2, (b) is a schematic sectional view thereof. In the absence of the power supply environment is a schematic configuration diagram of an electric resistance measuring device configured so as to measure the electrical resistance of the SO ₂ evaluation test body. The measurement method of the SO ₂ gas of the present invention is a schematic diagram of a measurement apparatus 1A for temperature compensation. It is an example of measurement of SO ₂ absorption amount of SO ₂ evaluation test body 2. An example of measurement of the resistance value of SO ₂ Evaluation test material 2 obtained from FIG. And the electric resistance relates to PbO ₂ plates is a graph showing measured values and calculated values of the relationship between mole fraction of PbO _2. It is a schematic block diagram for enforcing the measuring method of a 3rd embodiment of the present invention.

As a method for solving the above-mentioned problems, the present inventors focus on the fact that PbO ₂ having conductivity reacts with SO ₂ to form insulating PbSO ₄ , a test in which PbO ₂ and PbSO ₄ are mixed The relationship between the proportion of PbO ₂ and PbSO _{4 in} the body was investigated. As a result, the resistance value of the test body in which PbO ₂ and PbSO ₄ are mixed almost agrees with the resistance value assumed that PbO ₂ and PbSO ₄ are connected in series, and the resistance value Rs of the test body is It turned out that it can represent with Formula (1) of.

When the sample before PbSO ₄ formation is 100% PbO ₂ , the mole fraction of PbO ₂ in the sample before PbSO ₄ formation is 1.0. Therefore, when the content ratio of PbO ₂ in the above-mentioned test body after PbSO ₄ formation is represented by the mole fraction r, the formula (1) can be represented as follows.

FIG. 5 shows the electrical resistance (sometimes referred to simply as resistance in the present specification) for an SO ₂ evaluation test body consisting of PbO ₂ (resistivity: 68 Ωcm) and PbSO ₄ (resistivity: 5 × 10 ⁴ Ωcm). , A graph showing the measured value and the calculated value of the relationship with the mole fraction of PbO _{2, and as} the mole fraction of PbO ₂ initially decreases from 1.0, ie, the mole fraction of PbSO ₄ It can be seen that the resistance increases as the rate increases.

FIG as 5, SO ₂ evaluation test body, but those which are molded to a size of 65 × 36 × 3 mm are used, the production method is not particularly limited. For example, paste-like PbO prepared by dissolving 8.0 g of powdered tragacanth gum in 10 ml of alcohol and adding 8.0 g of lead dioxide powder to 5 ml of tragacanth gum solution to which 190 ml of pure water was added while stirring, and stirring with a glass rod ₂ with, may be prepared by drying after molding in a mold.

  Hereinafter, embodiments of a measurement method of the present invention and a measurement apparatus using the measurement method will be described. The same or similar parts are given the same or similar symbols. In addition, the embodiments described below illustrate a method or apparatus for embodying the technical idea of the present invention, and the technical idea of the present invention includes the shape, structure, arrangement, and the like of components. It does not specify the following. Various changes can be added to the technical idea of the present invention within the technical scope described in the claims.

First Embodiment
FIG. 1A is a flowchart of a first embodiment of the SO ₂ gas measurement method of the present invention. Moreover, FIG. 1B is the schematic of the measuring device 1 which implements the measuring method based on FIG. 1A.

The measuring device 1 will be described with reference to FIG. 1B. The measuring device 1 includes an SO ₂ evaluation test body 2, an electrical resistance measuring device 3, a correlation holding device 4, a test object content rate deriving device 5, and an output device 6. The SO ₂ evaluation test body 2 is connected to an external power supply (not shown) by power supply terminals 7 a and 7 b on the left and right sides thereof. The SO ₂ evaluation test body 2 is installed in an environment A surrounded by boundaries a1 and a2 such as walls, and an atmosphere in the environment A where at least a portion of the surface is a measurement target of the presence of SO ₂ gas. It is installed in environment A in an exposed state (exposed state) to be in direct contact with a2.

As the SO ₂ evaluation test body 2, for example, as shown in FIGS. 1D (a) and (b), a PbO ₂ plate 24 and electrodes 21 a and 21 b provided on the left and right ends of the PbO ₂ plate 24 in the longitudinal direction. The electrodes 21a and 21b may be provided on the inner surface, and may be configured to include a protective case 23 configured using an insulating material stable to a chemical reaction. Here, “PbO ₂ plate” means that the content of PbO ₂ is approximately 100%, and PbO ₂ is formed into a rectangular parallelepiped, a hexagonal column or the like, a columnar body having a polygonal cross section, or a flat plate The shape is not particularly limited.

In the first embodiment, the SO ₂ evaluation test body 2 uses a test body having a PbO ₂ content of 100%. The preparation method of SO ₂ evaluation test body 2 is not particularly limited, but as described above, for example, lead dioxide powder is dissolved in tragacanth gum solution to which powdered tragacanth gum is dissolved in alcohol and pure water is added while stirring. It can be prepared by forming paste-like PbO ₂ prepared by stirring with a glass rod.

The shape and size of the SO ₂ evaluation test body 2 may be appropriately set in accordance with the environment and period to be measured. By increasing the area of the exposed surface, the amount of reaction with sulfur dioxide gas can be increased, and the measurement sensitivity of sulfur dioxide gas can be enhanced. Also, like reducing the cross-sectional area of the surface not exposed, by increasing the resistance change of the SO ₂ Evaluation test material 2 for the reaction of the same sulfur dioxide gas, it is possible to increase the measurement sensitivity of the sulfur dioxide gas. For example, a rectangular parallelepiped or a cylinder can be used as the shape of the SO ₂ evaluation test body 2. For example, the thickness of the SO ₂ evaluation test body 2 is 0.1 cm or more and 0.5 cm or less, the length is 2 cm or more and 30 cm or less, and the width is 2 cm or more and 30 cm or less. The thickness is the vertical direction in FIG. 1B, that is, the length of one side of the surface to which the measurement terminals 3a and 3b of the resistance measuring device are connected, and the length is the horizontal direction in FIG. Is the distance between the surfaces to which the measurement terminal 3a is connected, and the width is the length of one side of the surface to which the measurement terminals 3a and 3b of the resistance measuring device are connected. .

The electrical resistance measuring device 3 is a device that measures the resistance of the SO ₂ evaluation test body. If the resistance of the SO ₂ evaluation test body can be measured, there is no restriction on the device configuration. The electrical resistance measuring device 3 in the first embodiment will be described with reference to FIG. 1C. The electrical resistance measurement device 3 includes a resistance measurement device 31, measurement terminals 3 a and 3 b of the resistance measurement device 31, and a terminal 3 c connected to the test piece content ratio deriving device 5. The measurement terminals 3a and 3b of the resistance measurement device 31 are connected to the SO ₂ evaluation test body 2, and the resistance measurement device 31 measures the electric resistance Rs by measuring the voltage between the left and right ends of the SO ₂ evaluation test object 2. At the same time, the measurement result is transmitted to the specimen content rate deriving device 5.

ただし、ａ、ｂ、ｃはそれぞれ係数であり、ｘはＳＯ_２評価試験体の電気抵抗を表す。 Correlation holding device 4 is a device in which the ratio of the content of the content and PbSO ₄ of PbO ₂ in the SO ₂ Evaluation test material 2, correlation between the electrical resistance of the SO ₂ evaluation test body is held. If the correlation corresponding to the shape etc. of the SO ₂ evaluation test body to be used for measurement is obtained in advance, and if the correlation holding device 4 holds the correlation, SO ₂ measured by the electrical resistance measuring device 3 From the electrical resistance of the evaluation test body 2, the ratio of the content of PbO _{2 and} the content of PbSO _{4 in} the SO ₂ evaluation test body 2 can be determined. The correlation held in the correlation holding device 4 is obtained by measuring the ratio of the electrical resistance to the content ratio for a sample in which the ratio of the content ratio of PbO _{2 and} the content ratio of PbSO ₄ is changed at several levels. , And each data can be obtained by approximation using the least squares method. The approximate expression of the least squares method can be expressed, for example, by a quadratic function (Expression 2) having an electrical resistance as a variable.

However, a, b and c are coefficients respectively and x represents the electrical resistance of the SO ₂ evaluation test body.

In addition, as a sample in which the content ratio of PbO _{2 and} the content ratio of PbSO ₄ are changed, a sample in which a content ratio of 100% of PbO ₂ is reacted with sulfur dioxide gas may be used. It is possible to artificially create a sample in which the ratio of the content of PbO _{2 and} the content of PbSO ₄ is adjusted so as to achieve the ratio. If the value of the electrical resistance of the correlation within the range where the SO ₂ gas is to be measured is substantially the same, the electrical resistance when the content of PbO ₂ is 100% or the content of PbSO ₄ is 100% The value of the electrical resistance of the above-mentioned correlation does not need to correspond.

The specimens content deriving device 5, that the electric resistance measuring device the electrical resistance of the SO ₂ Evaluation test material 2 to be measured at 3, to correspond to the correlation stored in the correlation holding device 4, SO ₂ The ratio of the content of PbO _{2 and} the content of PbSO _{4 in} the evaluation specimen 2 can be determined.

  The output device 6 is a device that outputs the correlation determined by the test object content rate derivation device 5. For example, the correlation may be recorded electronically by a data logger, or a temporal change of the correlation may be displayed as a graph on a display.

In the first embodiment of the SO ₂ gas measurement method of the present invention, first, based on the above-mentioned formula (1) or formula (1) ′, according to the measurement environment, the content of PbO ₂ and PbSO ₄ A correlation between the ratio and the electrical resistance is determined (step S1 of FIG. 1A). The determined correlation is stored in the correlation holding device 4.

Then, based on the correlation, an SO ₂ evaluation test body 2 suitable for a measurement environment is prepared, and the SO ₂ evaluation test body ₂ is used to measure SO ₂ gas using the SO ₂ evaluation test body. It arrange | positions in the environment A of measurement object (process S2 of FIG. 1A).

Next, the electrical resistance of the SO ₂ evaluation test body 2 in the environment A is measured using the electrical resistance measuring device 3 (step S3 in FIG. 1A). Based on the correlation between the proportion of the amount of PbO ₂ stored in the correlation holding device 4 and the electric resistance, the test body content deriving device 5 is used to measure the SO ₂ evaluation test body 2 in the environment The measurement result of the electrical resistance is converted into the ratio of the content of PbO _{2 and} the content of PbSO ₄ of the SO ₂ evaluation test body 2 in the environment A (step S 4 in FIG. 1A).

The SO ₂ absorption amount of the SO ₂ evaluation test body 2 in the environment A is converted to the existing state of SO ₂ gas in the environment A to be measured (step S5 in FIG. 1A). The presence of SO ₂ gas may be monitored by the output device 6 such as a monitor. The time-dependent change of the electrical resistance of the SO ₂ evaluation specimen ₂ in the environment A can be monitored as shown in FIG. 4 according to the present invention. Further, the change with time of the electric resistance of the SO ₂ evaluation test body 2 in the environment A is the SO ₂ adhesion degree of the SO ₂ evaluation test body 2 in the environment A as shown in FIG. 4 according to the present invention. Can be monitored as changes over time.

  In the measuring device 1 of FIG. 1B, the electrical resistance measuring device 3 is installed outside the environment A, but the electrical resistance measuring device 3 is in the environment A unless it is damaged by the atmosphere a2 in the environment A. It may be provided. Moreover, in the measuring device 1 of FIG. 1B, the electrical resistance measuring device 3 to the output device 6 are connected by wire, but data may be received and transmitted wirelessly.

Second Embodiment
FIG. 2A shows the electric resistance of the modification in which the electric resistance measurement device 3 of the measurement device 1 of the first embodiment can measure the electric resistance of the SO ₂ evaluation test body 2 in the absence of external power supply. It is a circuit diagram. This modified example is configured to be able to install the measuring device 1 also in a place where power supply is difficult, and when measuring the electrical resistance of the SO ₂ evaluation test body 2 in the environment A, A commercially available 1.5 V dry cell battery 70 can be used as a power source for energizing the SO ₂ evaluation test body 2.

As shown in FIG. 2A, in the second embodiment, the electrical resistance measuring device 3 includes a measuring device 31r for measuring a reference resistance, a reference resistor 30, and the resistance measuring device 31. The resistance measuring device 31 measures the electric resistance Rs (T) of the SO ₂ evaluation test body 2, and simultaneously with this measurement, the measuring device 31 r for reference resistance measurement measures the reference resistance 30.

In general, the electrical resistance of the SO ₂ evaluation test body 2 is preferably measured by a resistance meter. However, a resistor (reference resistance) whose resistance (Rr) is known is connected in series to the SO ₂ evaluation test body 2 and a voltage (E) applied to the entire resistance and a voltage (Er) applied to the reference resistance The electric resistance (Rs) of the SO ₂ evaluation test body 2 can be accurately determined according to the following equation 3 even by using a power supply whose voltage changes like a battery by measuring two voltages of It becomes possible.

As described above, by measuring the electric resistance of the SO ₂ evaluation test body 2 using the electric circuit shown in FIG. 2A, it becomes possible to measure for a long time using a battery even in a measurement environment where it is difficult to secure a power supply.

Third Embodiment
According to the measurement method and measurement apparatus of the present invention, obtained in advance the correlation between the ratio of content of the PbSO content of ₄ PbO ₂ of SO ₂ concentration and the SO ₂ evaluation test body 2 measured by a known method By setting, it is possible to measure the concentration of SO ₂ over time. In addition, by previously determining the correlation, it is possible to measure the SO ₂ concentration in different environments by using the correlation.

Hereinafter, the case of using a cylindrical method based on JIS Z 2382: 1998 (hereinafter simply referred to as “JIS Z 2383”) will be described. In the third embodiment of the present invention, the average SO of the environment to be measured is determined using the cylindrical method based on JIS Z 2382 with respect to the process of the first embodiment or the second embodiment. ₂ characterized in that it includes a step of measuring adhesion (unit: mg / dm ² / day). FIG. 6 shows a schematic configuration diagram for implementing the measuring method of the third embodiment of the present invention.

According to the process of setting the cylinder 100 in the environment to be measured using the cylinder method based on JIS Z 2382 and measuring the average degree of SO ₂ adhesion (unit: mg / dm ² / day) of the cylinder 100 Calculate the average amount of SO ₂ absorbed per day. The average amount of SO ₂ absorbed per day obtained by the cylindrical method based on JIS Z 2382 may be stored in the correlation holding device 4.

The third embodiment includes the step of measuring the time-dependent change of the SO ₂ absorption amount of the SO ₂ evaluation test body 2 and the average SO ₂ absorption amount per day in the same period as the exposure period of the cylindrical method. This step may be performed in step S3 of the first embodiment. As a device for measuring the time-dependent change of the SO ₂ absorption amount of the SO ₂ evaluation test body 2, the electrical resistance measurement device 3 of FIG. 1B may be used. Further, as a device for measuring the average SO ₂ absorption amount per day of the SO ₂ evaluation test body 2, the electrical resistance measurement device 3 or the test body content rate derivation device 5 of FIG. 1B may be used.

In the third embodiment, the average SO ₂ adhesion degree of the environment to be measured obtained using the cylindrical method based on JIS Z 2382, and the SO ₂ absorption amount of the SO ₂ evaluation test body 2 over time The process of converting the time-dependent change of SO ₂ absorption of the above-mentioned SO ₂ evaluation test body into the time-dependent change of SO ₂ adhesion degree by the above-mentioned cylindrical method by comparing with the average SO ₂ absorption of one day obtained from change Including. This step may be performed in step S4 and / or step S5 of the first embodiment using the test object content ratio deriving device 5 or the like of FIG. 1B.

Thus, according to the third embodiment of the present invention, it is possible to estimate quantitative sulfur dioxide gas measurement values by observing the rate of change from PbO ₂ to PbSO _{4 at} each elapsed time. Further, by obtaining the relationship between the resistance at the same time and the SO ₂ concentration by a known method, the resistance at a certain time can be converted to the SO ₂ concentration.

In the above-mentioned embodiment, although the SO ₂ evaluation test body 2 demonstrated the case where the content rate of PbO ₂ used a test body of 100%, it does not prevent containing the substance which has another electroconductivity. When a substance having another conductivity is contained, the SO ₂ evaluation test body 2 is made of PbO ₂ and PbSO ₂ in order to increase the resistance change rate to the amount of absorption of sulfur dioxide gas to increase sensitivity to sulfur dioxide gas. The content of PbO ₂ with respect to the content of ₄ is preferably 80% or more and 95% or less in molar fraction.

In addition, usually there is no problem because the temperature change of the environment does not greatly affect the measurement results, but when measuring in an environment where the temperature change is large, such as near equipment that emits a heat source that operates irregularly, If accurate measurement is desired, it is preferable to apply temperature compensation. To apply the temperature compensation, for example, as shown in FIG. 2B, a circuit for measuring the resistance of the SO ₂ evaluation test body 2 and a circuit for measuring the resistance of the temperature compensation resistor 20 protected from exposure to the environment. It can be installed under substantially the same environment and compensated using the temperature compensation resistor 20. In FIG. 2B, the temperature compensating resistor 20 is connected to an external power supply (not shown) through the terminals 8a and 8b, and the electrical resistance measuring device 13 is a resistor for each of the SO ₂ evaluation test body 2 and the temperature compensating resistor 20. The value is measured, and temperature compensation of the resistance value of the SO ₂ evaluation test body 2 is performed using the resistance value of the temperature compensation resistor 20.

  Thus, it goes without saying that the present invention includes various embodiments and the like which are not described herein. Accordingly, the technical scope of the present invention is defined only by the invention-specifying matters according to the scope of claims appropriate from the above description.

  Further, according to the present invention, by correlating with the corrosion behavior of the steel material measured continuously, it is effective for elucidating the corrosion of the steel material, and can be utilized for judging the applicability of the steel material component of the civil engineering construction material in the use environment.

Example 1
Using the apparatus of the first embodiment, in Amagasaki City, Hyogo Prefecture, the change over time in the presence of sulfur dioxide gas in Hyakuba box was continuously measured for a period of eight days in August. As the SO ₂ evaluation test body 2, a test body having a content of 100% of PbO ₂ was used.

The molar molecular weight of PbO ₂ is 239.198 g (density 9.38 g / cm ³ ), and the molar molecular weight of PbSO ₄ is 303.262 g (density 6.29 g / cm ³ ). When all the initial PbO ₂ contained in the SO ₂ evaluation test body 2 changes to PbSO ₄ , for example, when the PbO ₂ content of the SO ₂ evaluation test body 2 is 8 g, the PbO ₂ abundance ratio, That is, when the abundance ratio change of PbO ₂ / (PbO ₂ + PbSO ₄ ) is 1, the above-mentioned SO ₂ evaluation test body 2 is (8 × 1) ÷ 239.198 = 0.0334 mol of SO ₂ It will be absorbed.

Since the molar molecular weight of SO ₂ is 64.06 g, the SO ₂ evaluation test sample ₂ absorbed 0.0334 × 64.06 × 1000 = 2142 mg of SO ₂ .

If the weight of the initial SO ₂ evaluation test body 2 and the ratio of PbO ₂ / PbSO ₄ are known, it is possible to quantify the absorbed amount of SO ₂ using the molar fraction in which PbSO ₄ is increased.

For example, after 144 hours in FIG. 3, the PbO ₂ abundance ratio is 0.96. The reaction formula is “PbO ₂ + SO ₂ → PbSO ₄ ”, and it can be said that the reaction is performed with SO ₂ for the reduced number of moles of PbO ₂ . Therefore, the ratio of reaction with PbSO ₄ is 0.04 × (1−0.96). Since the initial weight of PbO ₂ is 8 g, the number of moles reacted from PbO ₂ to PbSO ₄ is 8 (g) × 0.04 × 1/239. 198 (mol / g) = 0.001338 (mol) is there. On the other hand, the mass of SO ₂ is 8 (g) × 0.04 × 1/239. 198 (mol / g) = 0.0857 (g).

Therefore, from the above calculation result, it is possible to derive 0.001338 mol of reacted mole number of SO ₂ after 144 hours in FIG. 3 and 0.0857 g of mass of SO ₂ .

  According to the method and apparatus for measuring sulfur dioxide gas of the present invention, it is possible to continuously measure the state of existence of sulfur dioxide gas which changes with time. Since the time-dependent change of sulfur dioxide gas can be measured continuously, it is effective in elucidation of corrosion of steel materials, and it can utilize for judgment of the applicability of steel materials of civil engineering and construction materials in a use environment.

1: sulfur dioxide gas measuring device 1A: sulfur dioxide gas measuring device 2: SO ₂ evaluation test body 3: electrical resistance measuring device 4: correlation holding device 5: specimen content ratio deriving device 6: output device 13: electricity Resistance measuring device 20: Resistance for temperature compensation 21a, 21b: Electrode 23: Protective case 24: PbO ₂ plate 31: Resistance measuring device 70: Dry cell 100: Cylindrical 131a: Resistance measuring device 131b: For measuring electric resistance of resistance for temperature compensation Resistance measuring machine A: Environment to be measured a1: Boundary of environment to be measured a2: Atmosphere in environment to be measured

Claims (6)

Containing PbO _2, at least a portion of PbO ₂ was exposed to the environment, the measurement of SO ₂ gas to measure the SO ₂ gas in the environment by using SO ₂ evaluation test body to absorb SO ₂ gas in the environment Method,
And determining the ratio of the PbO ₂ weight relative to the total amount of the PbO ₂ amount contained in the SO ₂ evaluation test body and PbSO ₄ amount, the correlation between the electrical resistance of the SO ₂ evaluation test body,
Placing the SO ₂ evaluation test body in an environment to be measured, and measuring the electrical resistance of the SO ₂ evaluation test body in the environment;
On the basis of the correlation, the SO ₂ to the measurement results of the electrical resistance of SO ₂ evaluation test body, characterized in that it comprises a step of determining the SO ₂ absorption amount of the SO ₂ evaluation test body in the environment How to measure gas. A series resistor is configured by connecting in series a reference resistor whose electric resistance is known and an SO ₂ evaluation test body, and the voltage E applied to the series resistor and the voltage Er applied to the reference resistor are measured. The method of measuring O ₂ gas according to claim 1, further comprising the step of obtaining the electric resistance Rs of the SO ₂ evaluation test body by the electric resistance Rr of the reference resistance and the following equation.

Further, a step of measuring an average SO ₂ adhesion degree (unit: mg / dm ² / day) in the environment to be measured using a cylindrical method based on JIS Z 2382: 1998,
Measuring a SO ₂ absorption amount of daily average SO ₂ absorption amount of the SO ₂ evaluation test body in the exposure period the same period and of the cylindrical method,
Determining a relationship between the average SO ₂ deposition rate and the average daily SO ₂ absorption amount;
And said average of SO ₂ degree of adhesion, on the basis of the relationship between the average of the SO ₂ absorption amount of the daily, the time course of SO ₂ absorption amount of the SO ₂ evaluation test of SO ₂ attaching degree by the cylinder method characterized in that it comprises a step of determining a change over time, measurement method of SO ₂ gas according to claim 1 or 2. Containing PbO _2, at least a portion of PbO ₂ was exposed to the environment, the measurement of SO ₂ gas to measure the SO ₂ gas in the environment by using SO ₂ evaluation test body to absorb SO ₂ gas in the environment A device,
The ratio of the PbO ₂ weight relative to the total amount of the SO ₂ Rating PbO ₂ amount contained in the specimen and PbSO ₄ amount, SO ₂ Evaluation created based on the correlation between the electrical resistance of the SO ₂ evaluation test body Test body,
An electrical resistance measuring device for measuring the electrical resistance of the SO ₂ evaluation specimen in the environment to be measured,
A correlation holding device for storing the correlation;
On the basis of the correlation, from the SO ₂ Evaluation of the electrical resistance of the specimen measurement results, to include a specimen content deriving device for obtaining the SO ₂ absorption amount of the SO ₂ evaluation test body in the environment Measurement equipment of SO ₂ gas which is characterized. Furthermore, a reference resistance whose electrical resistance is known and connected in series with the SO ₂ evaluation test body,
And a resistance measuring device for reference resistance which measures the electric resistance of the reference resistance,
The electrical resistance measuring device measures a voltage E applied to a series resistor consisting of the directly connected SO ₂ evaluation test body and a reference resistance and a voltage Er applied to the reference resistance, and 5. The apparatus for measuring O ₂ gas according to claim 4, further having a function of determining the electric resistance Rs of the SO ₂ evaluation test body by the electric resistance Rr and the following equation.

JIS Z 2382: measuring the SO ₂ absorption amount of aging and 1 day average SO ₂ absorption amount of the SO ₂ evaluation test body in the same period and the exposure period of the cylinder method based on 1998 SO ₂ absorption amount of time With the ability to measure changes,
The SO ₂ evaluation was made by comparing the average SO ₂ attachment degree (unit: mg / dm ² / day) in the environment of the measurement target obtained by the cylindrical method with the average SO ₂ absorption amount per day The apparatus for measuring SO ₂ gas according to claim 5 or 6, further comprising: a function of determining a change with time of the SO ₂ absorption amount of the test body with the change with time of the SO ₂ adhesion degree by the cylindrical method.

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