JP2001183357A - Oxidation apparatus assembly for total organic carbon measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxidation apparatus assembly, for a total organic carbon measuring system, by which total organic carbon in sample water can be oxidized and decomposed quickly and safely. SOLUTION: The oxidation apparatus assembly 10 is housed inside an enclosure 12. It uses an excimer lamp 14 which emits light at a very short wavelength, e.g. at a quasi-single wavelength of less than 184.9 nm. A housing 22 which is equipped with a sample-water entrance 18 and a sample-water exit 20 is connected to the enclosure so as to be freely detachable. An optical window member 30 which is composed preferably of MgF is installed between the enclosure and the housing airtightly and so as to be freely detachable. Thereby, an oxidation chamber 36 is constituted in a state that it is separated from the excimer lamp by the inner wall of the housing and by the optical window member. The light at the very short quasi-single wavelength from the excimer lamp is transmitted through the optical window member at the oxidation chamber, it flows inside the oxidation chamber so as to hit the sample water and an organic substance in the sample water is oxidized completely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a total organic carbon measurement system or TOC meter used for water quality inspection, and more particularly, to a component of the total organic carbon measurement system,
The present invention relates to an improvement in an oxidizer assembly for oxidizing organic substances in a sample water.

[0002]

2. Description of the Related Art For example, an apparatus of a total organic carbon measuring method for measuring the state of pollution of water quality by sewage and industrial effluent, especially by organic matter,
A so-called TOC meter is used. In such a system, the degree of pollution is represented by the amount of carbon in organic matter present in water. Since it is not possible to directly measure the total organic carbon (TOC) amount, it is necessary to oxidize organic matter in the sample water and convert it into carbon dioxide (CO ₂ ) before calculating the TOC amount. T
The OC meter includes, for example, an ultraviolet oxidation / conductivity change monitor type, a high temperature oxidation / carbon dioxide analysis type, a wet oxidation /
There is a carbon dioxide analysis type.

The measuring method of the ultraviolet oxidation / conductivity change monitor type will be described in detail. As is well known to those skilled in the art, the conductivity of sample water flowing through a measurement line is measured by a sensor, and then the sample is oxidized. To convert organic substances in the sample water into organic acids, for example, CO ₂ . Thereafter, the conductivity of the sample water is measured by a sensor, and the TOC amount is determined from known data based on the difference between the conductivity before and after the oxidation treatment obtained by the sensor.

[0004] In such a total organic carbon measuring system, a low-pressure mercury lamp (hereinafter referred to as "UV") is typically used for oxidation treatment.
A lamp is also used to irradiate the sample water flowing in the measurement line with ultraviolet rays. However, in such a conventional system, a considerably long irradiation time is required to completely oxidize the organic substances contained in the sample water in the measurement line by the ultraviolet rays, and the measurement takes time.

[0005] Therefore, an ultraviolet oxidation apparatus utilizing a photocatalyst has been developed to promote the oxidation of organic substances in the sample water. More specifically, such a UV oxidizer is provided in a measuring line and includes a transparent tubular portion containing a large number of glass beads coated with titanium oxide (TiO ₂ ) as a photocatalyst, and an adjacent tubular portion. U placed
A UV lamp that irradiates the sample water with ultraviolet light through the transparent tubular portion as the sample water flows through the transparent tubular portion. In addition, there is a conventional UV oxidizing apparatus in which an oxidizing agent, for example, sodium persulfate is added and mixed into sample water, and the mixture is irradiated with ultraviolet light from a UV lamp to promote oxidation of organic substances in the sample water. I have.

[0006] However, the ultraviolet oxidation apparatus of the photo-oxidation catalyst type has a drawback that a measurement error occurs due to interference of the photo-oxidation catalyst particularly in a low concentration TOC measurement region. In addition, in an oxidizing agent-added ultraviolet oxidation apparatus,
As the oxidant is consumed or needs to be replaced, the measuring operation has to be temporarily interrupted, which is cost-effective.

Further, the low-pressure mercury lamp used in the conventional total organic carbon measurement system has a different lamp irradiation efficiency depending on the environmental temperature (under the lamp lighting atmosphere). Therefore, it is necessary to keep the temperature in the lamp lighting atmosphere constant. was there.

[0008] In view of the drawbacks of the prior art, there is a need for an oxidizer assembly for a total organic carbon measurement system that rapidly and completely oxidizes and decomposes all organic carbon in sample water. An oxidizer assembly is provided.

[0009]

SUMMARY OF THE INVENTION The inventor of the present invention has conducted various trials and errors to use an extreme ultraviolet (vacuum ultraviolet) as a light source to emit only ultraviolet energy necessary for effectively decomposing TOC. By irradiating the sample water in the measurement line with a very short (eg, less than 184.9 nm) quasi-single wavelength light using a lamp, for example, an excimer lamp, the total organic carbon in the sample water can be very quickly and completely removed. Can be oxidatively decomposed. In addition, such excimer lamps are 1
It has also been found that light of a quasi-single wavelength of less than 84.9 nm can be emitted at a high output, so that an oxidizing agent (sodium persulfate) and a photo-oxidation catalyst (for example, TiO ₂ ) are not required. Further, since such an excimer lamp does not generate infrared rays, the oxidative decomposition of all organic carbon in the sample water can be performed at a low temperature.

Thus, the gist of the present invention is an oxidizer assembly for use in a total organic carbon measurement system, which houses a first light source, preferably an excimer lamp, which emits very short quasi-single wavelength light. A first enclosure,
An oxidation chamber disposed adjacent to the light source in a state separated from the light source and having a sample water inlet and a sample water outlet, wherein the oxidation chamber is partially configured by an optical window member; The light from the light source passes through the optical window member of the oxidation chamber and strikes sample water flowing in the oxidation chamber, and oxidizes organic substances in the sample water. In the device assembly.

[0011] Preferably, the oxidation chamber is formed in a housing, and the housing is detachably attached to the enclosure. With this configuration, the internal volume of the oxidation chamber through which the sample water flows can be changed in accordance with the requirements for measurement.

According to another feature of the invention, the oxidizer assembly of the invention further comprises a second light source that emits very short quasi-single wavelength light, the second light source comprising: A second optical window member is provided between the second light source and the oxidation chamber, the second optical window member being disposed adjacent to the oxidation chamber on a side opposite to the first light source and isolated from the oxidation chamber. Thus,
Since the sample water flowing through the inside of the oxidation chamber is irradiated with light of a quasi-single wavelength from both sides of the oxidation chamber, the complete oxidation of organic substances in the sample water is further promoted.

[0013] Preferably, the second light source is housed in a second enclosure, which is removably mounted on the housing of the oxidation chamber opposite the first enclosure.

According to another feature of the invention, the first and / or second optical window member is removably and hermetically provided between the first and / or second enclosure and the housing. Therefore, when impurities adhere to the surface of the optical window member or aging occurs, the optical window member can be easily replaced. The optical window member is made of MgF having a relatively excellent transmittance at a wavelength of less than 184.9 nm.

Since light having a short wavelength of less than 184.9 nm is absorbed by oxygen molecules, nitrogen gas which does not absorb the light having a short wavelength is placed in the first and / or second enclosure containing the light source. It is preferable that the purge gas composed of (N ₂ ) circulates and flows.

[0016]

FIG. 1 shows an oxidizer assembly 1 for a total organic carbon measurement system constructed in accordance with the teachings of the present invention.
0 is shown as a whole. The oxidizer assembly 10 has an elongated light source 14 housed in a tubular opaque enclosure 12 that emits very short quasi-single wavelength light. In a preferred embodiment of the present invention, such a light source is an extreme ultraviolet (or vacuum ultraviolet) lamp, such as an excimer lamp, which emits quasi-single (ie, has a relatively narrow spectral width) light in the region of about 200 nm or less. And most preferably a xenon (Xe) excimer lamp that emits light at a quasi-single wavelength less than 184.9 nm (peak of about 17
2 nm). Such an excimer lamp has an advantage that, in contrast to a low-pressure mercury lamp, the lamp irradiation efficiency is hardly affected by the ambient temperature, so that temperature control under a lamp lighting atmosphere is not required.

The excimer lamp 14 is preferably of a head-on type arranged so as to emit light from a head portion located on the right side in the drawing, and a pair of leads is provided from its base portion opposite to the head portion. A line 16 extends outwardly through the enclosure end face and is electrically connected to a power supply (not shown).

In a preferred embodiment of the present invention, a housing 22 having a sample water inlet 18 and a sample water outlet 20 is removably bolted to the end of the enclosure 12 via respective flanges. Inlet pipe 24 and outlet pipe 26 of the measurement line leading to the sample water sampling section (not shown)
Are connected to the sample water inlet 18 and the sample water outlet 20 of the housing 22 via fittings or pipe joints 28, respectively.

In the preferred embodiment shown, an optical window member 30 is removably disposed between the enclosure 12 and the housing 22. Such an optical window member may be made of, for example, MgF having a large transmittance in a wavelength in a far-ultraviolet region, for example, a wavelength of less than 184.9 nm, as compared with synthetic quartz which is generally used as an optical window material. preferable. As shown, an O-ring seal or gasket 32, preferably made of fluororesin, e.g., Teflon, is provided between the optical window member 24 and the end face of the enclosure 12, and further, the optical window member 24 and the housing are provided. 22 and an O-ring seal or gasket 3 preferably made of fluororesin, for example Teflon.
Thus, an oxidation chamber 36 is provided in the housing 22, which is isolated from the excimer lamp and is irradiated with light emitted from the excimer lamp through the optical window member 24. Although the enclosure 12, the housing 22, and the optical window member 24 may be integrally formed, as shown, the housing 22 is detachably fastened to the enclosure containing the excimer lamp 14 with the optical window member 30 interposed therebetween. Those skilled in the art will appreciate that the internal volume of the oxidation chamber in the housing can be changed according to the measurement requirements for total organic carbon in the sample water. Further, when replacement is necessary due to the attachment of impurities to the surface of the optical window member 30 or deterioration over time, this can be quickly replaced with a new optical window member, and the interruption time of the measurement operation can be minimized. It will be understood. The O-ring 34 may be of a metal seal type depending on the properties of the sample water. In order to make it difficult for impurities or organic compounds in the sample water to adhere to the inner wall of the housing 22, it is preferable to subject the inner wall of the housing to electropolishing.

The above-mentioned wavelength of less than 200 nm is generally easily absorbed by oxygen molecules, in other words, oxygen becomes ozone, which reduces the irradiation efficiency of the excimer lamp. The purge gas may be constantly circulated in the hollow portion, and for this purpose, the enclosure is provided with a purge gas inlet 38 and an outlet 40 at appropriate intervals as shown in the figure. As the purge gas, it is preferable to use a nitrogen gas having low absorptivity and reactivity with respect to light having a short wavelength as described above. Thus, the purge gas inlet line 42 leading to the nitrogen gas source is connected to the purge gas inlet 38 of the enclosure 12 and the purge gas outlet line 44 is connected to the purge gas outlet 40 of the enclosure 12 to constantly flow nitrogen gas around the excimer lamp in the enclosure 12. When this is done, the light emitted from the excimer lamp passes through the optical window member 30 without much attenuation and is irradiated on the sample water flowing in the oxidation chamber.
Good oxidative decomposition efficiency of organic matter in sample water. As a modification, although not shown, even if the nitrogen gas is not circulated as described above and is enclosed in the hollow portion of the enclosure 12 accommodating the excimer lamp 14, an acceptable level of organic substance oxidative decomposition effect can be obtained. In this case, it goes without saying that the purge gas inlet 38 and the outlet 40 are plugged after the nitrogen gas is sealed in the enclosure 12 shown in FIGS. 1 and 2.

FIG. 2 shows an oxidizer assembly 100 as a modified embodiment of the present invention, which is configured to further promote the oxidative decomposition of organic substances in the sample water. As can be seen in FIG. 2, the oxidizer assembly 100 is identical in configuration to the individual components of the oxidizer assembly 10 of FIG. 1 (therefore, the oxidizer assembly 100 has the same or corresponding components as those of FIG. 1). Is
In the drawing, the left side is denoted by a prime symbol ('), and the right side is denoted by a symbol (")), and a head-on type excimer lamp 14' is provided on the opposite side of the oxidation chamber 36. , 14 ", respectively, are arranged facing each other, and the oxidation chamber 3
The sample water flowing through the inside 6 is irradiated with light from both sides. Again, the enclosures 12 ', 12 "are fastened to the oxidation chamber housing 22' via flanges, between which optical window members 30 ', 30", respectively, are hermetically and in substantially the same manner. It is provided interchangeably. As shown, the purge gas outlet 40 'of the enclosure 12' and the purge gas inlet 38 'of the opposite enclosure 12 "
And therefore the purge gas inlet line 4
A purge gas comprising nitrogen gas in 2 'flows into the enclosure 12' via an inlet 38 ', flows around the excimer lamp 14', flows from the purge gas outlet 40 'of the enclosure to the connecting pipe 46, and It enters the opposite enclosure 12 "via inlet 38", flows around excimer lamp 14 "and exits enclosure 12" via purge gas outlet 40 "and purge gas outlet line 44".

Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art will be able to conceive various modifications of the disclosed form. It is determined based on the description in the claims and the equivalents thereof.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the oxidizer assembly of the present invention used in a total organic carbon measurement system used for water quality inspection, with a head provided in an enclosure on one side of an oxidation chamber. It is a partial section side view showing an ON type excimer lamp.

FIG. 2 is a view similar to FIG. 1 showing a dual excimer lamp based oxidizer assembly as an alternative embodiment of the present invention, provided on opposite sides of the oxidation chamber;
FIG. 2 is a diagram showing a head-on type excimer lamp housed in an enclosure.

[Explanation of symbols]

 10, 100 Oxidizer assembly 12, 12 ', 12 "Enclosure 14, 14', 14" Head-on type excimer lamp 22, 22 'Housing 24 Sample water inlet tube 26 Sample water outlet tube 30, 30', 30 "Optical Window member 36 Oxidation chamber

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[Procedure amendment]

[Submission date] January 6, 2000 (200.1.6)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

Claims (9)

[Claims] An oxidizer assembly for use in a total organic carbon measurement system, comprising: an enclosure containing a light source that emits very short quasi-single wavelength light; and the light source isolated from the light source. And an oxidation chamber provided with a sample water inlet and a sample water outlet, the oxidation chamber being partially constituted by an optical window member, and the light from the light source being transmitted to the oxidation chamber. An oxidizing apparatus assembly for oxidizing organic matter in the sample water by hitting the sample water flowing through the optical window member and flowing in the oxidation chamber. 2. The oxidizer assembly according to claim 1, wherein the oxidizing chamber is formed in a housing, and the housing is detachably attached to the enclosure. 3. A light source that emits very short quasi-single wavelength light, the second light source being isolated from the oxidation chamber on the opposite side of the light source. 3. The oxidizer assembly according to claim 1, wherein a second optical window member is provided between the second light source and the oxidation chamber, the second optical window member being provided adjacent to the chamber. 4. The method according to claim 1, wherein said second light source is housed in a second enclosure, said second enclosure being removably mounted to said housing of said oxidation chamber on an opposite side of said enclosure. The oxidizer assembly of claim 3, wherein: 5. The oxidation according to claim 1, wherein the optical window member is detachably and hermetically provided between the enclosure and the housing. Equipment assembly. 6. The oxidizer assembly according to claim 1, wherein said optical window member is made of MgF. 7. The oxidizer assembly according to claim 1, wherein the light source is an excimer lamp that emits light having a wavelength of less than about 184.9 nm. 8. The oxidizer assembly according to claim 1, wherein a purge gas made of nitrogen gas circulates and flows in the enclosure accommodating the light source. 9. The oxidizer assembly according to claim 1, wherein a nitrogen gas is sealed in the enclosure accommodating the light source.