JP2002071668A - Analysis device for trace component in gas, and analysis method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an analysis device for trace components in gas having excellent response speed by preventing chlorophenol from adsorbing to the internal wall surface or the like of a cooling device in the case of providing the analysis device with the cooling device for producing water content from steam in gas to remove a halide. SOLUTION: In this analysis device for trace components in gas and the analysis method using the analysis device, the cooling device is provided for cooling steam in the gas to become water content, and a drain pot where the halide is dissolved in the water content and removed, is communicated with the cooling device. A passage is provided for merging exhaust gas from the drain pot, into a position downstream of a detector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for analyzing trace components in a gas and an analysis method using the same, and more particularly, to chlorobenzenes and chlorophenols which are effective as substitute indicators for dioxins in exhaust gas generated from a combustion apparatus. And related analytical methods.

[0002]

2. Description of the Related Art The content of dioxins in exhaust gas generated from a combustion device or the like is very small, and it is extremely difficult to accurately and quantitatively analyze them. For this reason, a method of estimating the concentration of dioxins based on the analysis results has been adopted, using the concentration of dioxin precursor having a correlation with the concentration of dioxins as an alternative index. As alternative indices, JP-A-5-321796 and JP-A-9-15229 disclose methods using chlorobenzenes or chlorophenol. The concentration of these dioxin precursors is higher than the concentration of dioxins and can be measured with an existing analyzer.

[0003] As an alternative index for dioxins,
There is a method in which chlorobenzenes, chlorophenols, or the total amount thereof is measured using a gas chromatograph method or an electrochemical method, and the dioxin concentration is measured from a correlation between the measured value and dioxins.

In order to measure the dioxin concentration with higher precision, quantitative analysis of chlorophenol is performed using a mass spectrometer based on a change in signal intensity corresponding to the mass number of a fragment specific to chlorophenol, which is a dioxin precursor substance. I do. There is a method of measuring the dioxin concentration from the correlation between the analytical value and dioxins. However, when a conventional analyzer is used, detection alien components such as hydrogen chloride, hydrogen bromide, nitrogen oxides, and sulfur oxides often coexist in exhaust gas generated by a combustion device, etc. There is a problem that the strength is significantly reduced.

As a solution to this problem, Japanese Patent Laid-Open Publication No. 2000-18
Japanese Patent No. 0707 discloses means for cooling and condensing water vapor contained in exhaust gas by a cooling device, and dissolving and removing halides (exception alien components) such as hydrogen chloride and hydrogen bromide in the exhaust gas in the generated moisture. Discloses a method and an apparatus for analyzing chlorophenol in a gas provided with: However, in this invention, there is a problem that the response speed of the analyzer decreases because chlorophenol is adsorbed to the peripheral portion (such as the inner wall surface) of the cooling device cooled to about room temperature.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a cooling system for producing water from water vapor in a gas, further dissolving a halide in the water, and removing the halide out of the sample channel system. Provided is an apparatus for analyzing trace components in gas with high response speed and high accuracy by eliminating the adsorption of chlorophenol or chlorobenzenes on the inner wall surface or the like of a cooling device, and an analysis method using the same.

[0007]

The gist of the present invention for solving the above-mentioned problems is as follows. (1) a cooling device for cooling water vapor in a gas to make water, which is connected to a drain pot for dissolving a halide in the water and retaining the halide;
This is a device for analyzing a trace component in a gas having a flow path for allowing the exhaust gas from the drain pot to join a downstream position from a detector of the analyzer. (2) In a trace component analyzer for analyzing a trace amount of organic compounds contained in a gas, water vapor in the gas is cooled to generate water, and a halide is dissolved in the water to remove the halide. A trace component analyzer in a gas having a pretreatment means, and a flow path in which exhaust gas from a drain pot for collecting the water merges with a detector of the trace component analyzer to a downstream position.

A flow path for discharging the water produced by cooling directly from the detector of the analyzer through a pipe to a downstream position, and a flow path for the exhaust gas from the drain pot; It is preferable to provide a flow control valve for adjusting the amount. (3) In a method for analyzing a trace amount of an organic compound contained in a gas generated by a combustion device using a trace component analyzer, water vapor is cooled in the gas to generate water, and a halide is contained in the water. It is preferable to have a pretreatment means for dissolving the halide to remove the halide, and to analyze in a state where the drain pot for collecting the water is cooled to room temperature or lower.

In the pretreatment apparatus and method for analyzing trace components in gas, chlorophenol is adsorbed and chlorophenol gradually released therefrom flows to a downstream side of a detector of the analyzer of the analyzer. Is provided, the response speed of the analyzer can be remarkably improved.

Furthermore, the amount of gas flowing to the detector of the analyzer is determined by the flow of gas discharged from the drain pot for storing the water discharged from the cooling device to the downstream of the detector of the analyzer. By optimizing, an analysis method with an improved response speed can be provided.

[0011]

FIG. 1 is a system diagram of an analyzer according to the present invention.

After the gas to be analyzed discharged from the combustion device 17 flows through the dust removal device 15 in the sampling box 16, the cooler inlet valve 12 or the cooler bypass valve 13
Is led to the cooling device main body 1 or the analyzer 7. That is, in the present invention, the cooling device main body 1 is installed upstream of the analyzer 7.

The exhaust gas flowing into the cooling device main body 1 is cooled in the course of flowing through the spiral installation pipe 20, and the high-temperature exhaust gas is cooled inside the cooling device main body 1, the water vapor in the gas is condensed, and Become. This water flows through the condensed water discharge line 9 and is collected in the condensed water collecting drain pot 2. Here, hydrochloric acid (HCl), a contaminant component,
Has high solubility in water and is absorbed and removed by water. Chlorophenol, which is a substance to be measured, has a lower solubility in water than HCl, but dissolves in a certain amount or adheres and adsorbs to the inner wall surface of the condensed water collecting drain pot 2.

The condensed water in which the detection inhibiting component such as HCl is dissolved is continuously discharged from the cooling device main body 1 through the condensed water discharge line 9 and is collected in the condensed water collecting drain pot 2. The absorbed and adsorbed chlorophenol is scattered with time from the water in the drain pot and the inner wall surface of the container. In order to improve the response speed of the analyzer, the outlet gas discharge line 3 of the condensed water recovery drain pot 2 is introduced into a downstream position so as not to be introduced into the detector (ionization unit) 5.

On the other hand, the gas component flowing through the spiral installation pipe 20 passes through the cooler outlet pipe 21 and passes through the cooler outlet valve 1.
4 guides the analyzer 7.

Next, the present invention will be described specifically with reference to examples.

[0017]

Embodiment 1 (Example of Pretreatment System for Chlorophenol Analyzer) FIG. 1 is a system diagram showing a configuration of a pretreatment system for a precursor analyzer of the present invention. The system is roughly divided into a cooling device body 1, a condensed water recovery drain pot 2,
Analysis device 7, sampling box 16 and combustion device 1
7 is comprised. The procedure of the analysis operation is as follows: (1) standard substance verification, (2) introduction of gas into the cooling device, (3) introduction of actual gas,
Divided into The standard material is verified by the cooling device inlet valve 12,
The cooling device outlet valve 14 is closed and the cooling device bypass valve 13 is closed.
Is opened, and the 13C type chlorophenol is supplied from the standard substance generator 10 to the detection unit (ion source) 5 through the standard substance introduction line 11. In actual gas introduction, exhaust gas generated in the combustion device 17 is introduced into the cooling device main body 1. At this time,
When the cooling device is introduced, the cooling device bypass valve 13 is closed, and the cooling device inlet valve 12 and the cooling device outlet valve 14 are opened to introduce gas into the cooling device body 1.

In the condensed water 19 collected in the condensed water collecting drain pot 2, HCl and chlorophenol removed from the exhaust gas are dissolved. The condensed water collecting drain pot 2 is kept near room temperature, and HCl and chlorophenol equivalent to the vapor pressure corresponding to the temperature are scattered and discharged.

A part of the gas introduced from the cooling device inlet valve 12 to the cooling device main body 1 is discharged from the condensed water discharge line 9, and the gas contains HCl and chlorophenol. If chlorophenol scatters sequentially from the condensed water recovery drain pot 2, it is detected even when chlorophenol is not contained in the exhaust gas, causing a reduction in response speed and a measurement error due to residual components (decrease in analysis accuracy). Leads to.

Therefore, in the present embodiment, the performance degradation as described above can be prevented by merging the pot outlet gas discharge line 3 of the condensed water recovery drain to the downstream position of the detection unit 5. Since the gas contains water vapor, water is further removed by the drain pot 6.

A flow control valve 4 is installed in the outlet gas discharge line 3 of the condensed water recovery drain pot. The amount of gas flowing through the outlet gas discharge line 3 is adjusted by adjusting the opening of the valve 4. And the amount of gas flowing from the cooling device outlet valve 14 is controlled.

From the results of the implementation, it is possible to improve the response speed when the amount of gas introduced from the cooling device inlet valve 12 increases. This is because the gas contact portion 20 in the cooling device 1 has a low temperature,
Here, chlorophenol is adsorbed. Gas contact part 2
Since a spiral guide for promoting the residence time of the flowing gas is installed in the inner tower of
In this case, the amount of chlorophenol adsorbed increases. Therefore, when the amount of gas flowing through this portion is increased, the amount of chlorophenol adsorbed at the portion is increased, and the response speed is improved.

The gas contact part 21 is provided inside the cooling device 1.
However, this part is simply a pipe, and it is considered that the adsorption amount of chlorophenol is small. In order to reduce the amount of chlorophenol adsorbed here, there are two methods in which the amount of gas flowing through the gas contact portion 21 is increased to increase the amount of desorption, or the amount of gas flowing through the gas contact portion 21 is reduced. There is. It is necessary to optimize the amount of gas by adjusting the opening of the flow control valve 4.

Further, if the outlet gas discharge line 3 of the condensed water recovery drain pot is introduced downstream of the detection unit 5, it is possible to prevent the chlorophenol signal intensity from being attenuated by HCl contained in the gas.

FIG. 2 shows the effect of the first embodiment. The horizontal axis shows the elapsed time, and the vertical axis shows the residual ratio of chlorophenol. In the response performance evaluation test, a sample holder filled with chlorophenol is installed in the standard substance generator 10 of FIG. 1 in advance to acquire signal intensity data. Assuming that the time when the sample holder was removed was 0, the time-dependent change in the residual ratio of chlorophenol remaining in the entire system of the analyzer was measured.

The residual ratio of chlorophenol was determined by the following equation. Residual rate (%) of elapsed time a (minutes) = (chlorophenol signal intensity for elapsed time a) / (chlorophenol signal intensity for elapsed time 0) In FIG. The new method in the example is indicated by ● and □ (solid line). The conventional method is a device in which the outlet gas discharge line 3 of the condensed water recovery drain pot is joined to the upstream position of the detection unit 5, and the new method is that the outlet gas discharge line 3 of the condensed water recovery drain pot is located downstream of the detection unit 5. The response performance of the device that was joined to was evaluated.

The new method is that the gas contains HCl at 202 pp.
The case where m is contained (●) and the case where HCl is not contained (□) are shown. The temperature of the cooling device is 30 ° C., the gas amount is 3 l / min, and the water vapor concentration in the gas is 13.3%.
It is.

When the elapsed time is a minute and the two are compared, the residual ratio of chlorophenol in the conventional method is 35.7%, whereas in the new method, when HCl is 202 ppm, 15.
When it was 3% and HCl was 0 ppm, it was 14.2%, and the residual ratio of chlorophenol could be reduced by about 20%.

FIG. 3 shows the result of the operation method of the first embodiment.
The horizontal axis shows the elapsed time, and the vertical axis shows the residual ratio of chlorophenol. Here, the response performance when the opening degree of the flow control valve 4 was changed was compared. The temperature of the cooling device was 30 ° C., the gas amount at the cooling device inlet was 3 l / min, and the water vapor concentration in the gas was 13.8%. In the figure, ■ indicates a state where the valve opening is 3/5 open, and □ indicates a state where the valve is fully open. Comparing the residual ratio of chlorophenol at the same elapsed time, the residual ratio is smaller and the response performance is better when the valve opening is 3/5. When the valve opening degree is reduced, the amount of gas flowing through the outlet gas discharge line 3 of the condensed water recovery drain pot decreases, and the amount of gas flowing through the pipe 21 in the cooling device 1 increases. As a result, the piping 21
Chlorophenol adsorbed on the surface was easily desorbed and the response was improved.

[0030]

Embodiment 2 FIG. 4 is a system diagram showing the configuration of the analyzer of the present invention. In the present embodiment, the condensed water drain pot 2 is omitted from the configuration of the first embodiment, and the condensed water discharge line 9 is directly introduced into the downstream of the detector 5. Since there is no drain pot 2 for condensed water, facility costs are easy, and maintenance and inspection are also easy.

[0031]

Third Embodiment FIG. 5 is a system diagram showing the configuration of another analyzer according to the present invention. In this embodiment, the outlet gas discharge line 22 of the condensed water recovery drain pot 2 having the structure of the first embodiment is made as thin as possible to reduce the amount of gas flowing therethrough.
Since the amount of gas flowing here is determined by the pipe pressure loss, the flow regulating valve 4 installed in FIG. 1 is not required.

[0032]

Embodiment 4 FIG. 6 is a system diagram showing the configuration of another analyzer according to the present invention. In this embodiment, the condensed water drain pot 2 is cooled by a cooling tank 25 to room temperature or lower. A flow rate control valve 4 is provided in the outlet gas discharge line 3 of the condensed water recovery drain pot, and the opening degree of the valve 4 is adjusted.
The amount of gas flowing through the outlet gas discharge line 3 and the amount of gas flowing from the cooling device outlet valve 14 are controlled to introduce gas into the detector 5. Chlorophenol and HCl adsorbed on the inside of the condensed water 19 and on the surface of the condensed water drain pot 2 have a low temperature, so that it is difficult to dissipate into the gas, the amount flowing into the detector 5 is reduced, and the response speed is improved.

[0033]

Embodiment 5 FIG. 7 is a system diagram showing the configuration of still another analyzer according to the present invention. In the present embodiment, 2
This is the case where a series cooling pipe is installed. In the first line, the gas flowing from the cooler inlet valve 12 is cooled, and in the second line, the chlorophenol contained in the gas flowing into the detector 5 while the outlet gas from the condensed water drain pot in the first line is cooled. And HCl. Thereby, the response speed and the analysis accuracy were improved.

[0034]

According to the present invention, when a cooling device for generating moisture from water vapor in a gas to remove a halide is provided in an analyzer, the water scatters from a drain pot for collecting condensed water from the cooling device. Gas with excellent response speed to chlorophenol is set by flowing chlorophenol to a position that does not affect the detector of the analyzer and by setting the flow rate so that chlorophenol adsorbed to the piping inside the cooling device is easily desorbed. Provide a device for analyzing trace components in water.

[Brief description of the drawings]

FIG. 1 is a system diagram showing another configuration of the analyzer according to the first embodiment of the present invention.

FIG. 2 shows the response performance of a preprocessing system for an analyzer according to the present invention.

FIG. 3 is a system diagram showing operating conditions and response performance of the analyzer of the present invention.

FIG. 4 is a system diagram showing another configuration of the analyzer according to the second embodiment of the present invention.

FIG. 5 is a system diagram showing another configuration of the analyzer according to the third embodiment of the present invention.

FIG. 6 is a system diagram showing another configuration of the analyzer according to the fourth embodiment of the present invention.

FIG. 7 is a system diagram showing another configuration of the analyzer according to the fifth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cooling device main body, 2 ... Drain pot for condensed water, 3 ...
Condensed water recovery drain outlet gas discharge line, 4 ...
Flow control valve, 5: detector (ion source), 6: second drain pot, 7: chlorophenol analyzer, 8: exhaust blower for analysis, 9: condensed water discharge line, 10: standard substance generator, 11 ... Standard substance introduction line, 12: cooling device inlet valve, 13: cooling device bypass valve, 14: cooling device outlet valve, 15: dust removal device, 16: sampling box, 1
7: Combustion device, 18: Flue, 19: Condensed water, 20: Spiral installation piping, 21: Cooler outlet piping, 22: Extra-fine condensed water recovery drain pot outlet gas discharge line, 2
3 ... ionization part introduction line, 24 ... ionization part bypass line, 25 ... cooling tank.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Jun Morihara 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Electric Power & Electric Research Laboratory, Hitachi, Ltd. (72) Inventor Shozo Sakamoto Hitachinaka City, Ibaraki 882 Ichige Co., Ltd. Within Hitachi Measuring Instruments Group (72) Inventor Tomoyuki Tobita Tomoyuki Tobita 822, Oji-shi, Hitachinaka-shi, Ibaraki Co., Ltd. Hitachi Manufacturing Co., Ltd. Measuring Instruments Group F term (reference)

Claims (5)

[Claims] 1. A cooling device for cooling water vapor in a gas to convert the water into water. The cooling device is connected to a drain pot for dissolving a halide in the water and retaining the halide. An apparatus for analyzing a trace component in a gas, comprising: a flow passage for allowing the exhaust gas from the detector to join a downstream position from the detector. 2. A trace component analyzer for analyzing a trace amount of organic compounds contained in a gas, wherein water vapor in the gas is cooled to generate moisture, and the halide is dissolved in the moisture to form the halide. Has a pre-processing means for removing
An apparatus for analyzing a trace component in a gas, comprising: a flow passage through which an exhaust gas from a drain pot for collecting the water joins a downstream position from a detector of the analyzer for a trace component. 3. The trace component analyzer in a gas according to claim 1, wherein the analyzer has a flow path for discharging the water produced by cooling directly from a detector of the analyzer to a downstream position through a pipe. 4. The apparatus according to claim 1, wherein a flow control valve for adjusting an outflow gas amount is provided in a flow path of the exhaust gas from the drain pot. 5. A method for analyzing a trace amount of an organic compound contained in a gas generated by a combustion device using a trace component analyzer, wherein water vapor in the gas is cooled to generate moisture, and A method for analyzing trace components in gas, comprising a pretreatment means for dissolving a halide and removing the halide, wherein the analysis is performed in a state where a drain pot for collecting the water is cooled to room temperature or lower.