JPH0627731B2 - Total Organic Carbon Analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a total organic carbon analyzer. More specifically, it relates to a total organic carbon analyzer capable of determining only volatile organic carbon in total organic carbon (TOC) in water.

(B) Conventional technology Conventionally, as a total organic carbon analyzer for measuring organic matter in water, a total carbon (TC) equipped with a carrier gas supply unit, a sample inlet, a high temperature heating furnace, and a combustion catalyst for total carbon (TC ) In an analysis channel connecting an inorganic carbon (IC) reaction tube equipped with a reaction tube, a sample inlet and a low-temperature heating furnace and equipped with a reaction catalyst for inorganic carbon, and a non-dispersive infrared gas detector for detecting carbon dioxide Composed combustion-infrared total organic carbon analyzers are known. As the TC reaction tube, for example, a surface of alumina coated with platinum black or a material of granular cobalt oxide or the like filled as an oxidation catalyst is used. On the other hand, the IC reaction tube has a quartz chip surface with phosphoric acid. Those coated with or those filled with an ion exchange resin are used. Normally, in the analyzer having the above-mentioned configuration, the TC reaction tube is heated to about 650 ° C or higher, while the IC
The reaction tube is heated to about 120 to 150 ° C. Total organic carbon (T
When measuring OC), TOC is measured by the difference between TC measured by injecting a sample into a sample introduction part and IC measured by injecting the same amount of the same sample into an IC reaction tube.

(C) Problems to be Solved by the Invention By the way, organic substances contained in water include low-boiling point organic substances. Of these, the components that volatilize (vaporize) in a short time only by aerating (bubbling) the sample with nitrogen gas or air at room temperature
It is called OC (purgable organic carbon), and it is a useful measurement item for investigating water pollution due to organic solvents. In addition, the components that can be measured by heating the sample to 100-150 ℃ and aerating the sample are added to the VOC (volatile organic car).
bon).

Conventionally, the total organic carbon (TO
C) In addition to the analysis flow path system of the analyzer, a POC vaporizer and a scrubber for removing carbon dioxide from the vaporized gas generated in the vaporizer are newly provided, and the gas transferred from the scrubber is analyzed by the TOC analyzer. Carbon dioxide is detected by the non-dispersive infrared gas detector. However, the detection of such another configuration is complicated.

The present invention has been made in view of such circumstances, and
It is intended to provide a TOC analyzer capable of measuring C and arbitrary VOC.

(D) Means for Solving the Problems Thus, according to the present invention, an analysis channel that connects a carrier gas supply unit, a total carbon (TC) reaction unit, an inorganic carbon (IC) reaction unit, and a carbon dioxide detection unit in this order. In an all-organic carbon analyzer having the above, an oxidation reaction part equipped with a carbon dioxide absorption part and a heating means is provided in this order between the IC reaction part and the carbon dioxide detection part, and volatilized in the IC reaction part. Alternatively, after the carbon dioxide is absorbed and removed from the carrier gas containing the vaporized organic matter, a bypass flow path capable of oxidizing the volatilized or vaporized organic matter and transferring it to the carbon dioxide detector is switchably attached. A total organic carbon analyzer is provided.

One of the features of the analyzer of the present invention is that it is an analyzer configured to be able to measure both total organic carbon and volatile organic carbon in total organic carbon. That is, the IC reaction section is also used as a vaporization section for volatile organic carbon, and a bypass flow path for measuring the volatile organic carbon is provided switchably.

In the present invention, the volatile organic carbon to be measured means carbon derived from a low boiling point organic substance, and specifically, it is volatilized (vaporized) in a short time only by aerating (bubbling) a sample with nitrogen gas or air at room temperature. ) Component (hereinafter referred to as POC),
It means a component (hereinafter referred to as VOC) that can be measured by heating the sample to about 100 to 150 ° C. and aerating the sample.

In the TOC analyzer of the present invention, as the inorganic carbon (IC) reaction part, a normal one composed of a reaction tube equipped with a sample inlet and a reaction catalyst for inorganic carbon can be used as it is. Further, it is preferable to use the low-temperature heating furnace which is usually equipped as it is. As the above-mentioned reaction catalyst for inorganic carbon, a liquid acid such as phosphoric acid or one obtained by impregnating it with a carrier, an acidic crystal such as a primary phosphate, or a solid acid such as a strongly acidic cation exchange resin is used. Ordinary ones such as these can be used as they are. In the present invention, since this IC reaction part is also used for volatilization (vaporization) of volatile organic substances,
It is preferable that the sample liquid injected into the device can be held so as to be in efficient contact with the carrier gas passing through the IC reaction part, and the desired volatile organic substance can be volatilized (vaporized) in the meantime. It is preferable to use the above ion exchange resin from the standpoint that the reacted sample is not discharged as a drain when it is discharged.

The bypass flow passage attached to the analysis flow passage of the present invention has a carbon dioxide absorption portion and an oxidation reaction portion provided with a heating means, and a carrier gas containing a volatile organic substance volatilized (vaporized) in the IC reaction portion. Through the switching means in the analysis flow path connecting the IC reaction part and the carbon dioxide detection part so that the carbon dioxide is transferred to the carbon dioxide detector of the TOC analyzer through the carbon dioxide absorption part and the oxidation reaction part in this order. Connected.
The carbon dioxide absorption part removes carbon dioxide generated in the IC reaction part, and lithium hydroxide can be used as an absorbent. The oxidation reaction part may be the same as the TC reaction part such as platinum, palladium, cobalt oxide. Also, the heating means provided is about 200 to about
The same thing as that provided in the TC reaction part that can be heated in the range of 1,000 ° C. can be used. Further, as the switching means for switching and connecting the bypass flow channel and the TOC analysis flow channel, an ordinary flow channel switching device such as an electromagnetic valve or a rotary valve can be used.

When measuring volatile organic substances with the TOC analyzer of the present invention, when the POC is intended to be measured, it is usually unnecessary to heat the IC reaction part, and it is possible to perform it only by purging the carrier gas. Further, when the VOC measurement is intended, the carrier gas heated to a predetermined temperature up to about 150 ° C. is purged, or the temperature of the IC reaction part is increased up to about 150 ° C. by the heating means provided in the IC reaction part. It becomes possible by heating to a predetermined temperature and purging the carrier gas.

In the TOC analyzer of the present invention, the carrier gas supply unit, the TC reaction unit, and the carbon dioxide detection unit are conventional TOC analyzers.
The same thing as that provided in the analyzer can be used.

(E) Action According to the present invention, when the measurement of volatile organic substances in a sample is intended, the carrier gas supply section → total carbon (TC) reaction section → inorganic carbon (IC) reaction section → carbon dioxide detection section A part of the TOC measurement analysis flow path that is communicated in order is switched and connected so as to pass through the bypass flow path, and as a result, the carrier gas supplied from the carrier gas supply unit is the total carbon (T
C) The reaction section → the inorganic carbon (IC) reaction section → the carbon dioxide absorption section → the oxidation reaction section → the carbon dioxide detection section are transferred in this order in the flow path communicating with each other. At this time, the sample injected into the IC reaction part is held in the reaction part and is purged by the carrier gas flowing through the reaction part, and the volatile organic substances volatilized from the sample are transferred to the carbon dioxide absorption part by the carrier gas. Be transferred. After the carbon dioxide contained in the carrier gas is previously absorbed and removed in the absorber,
This carrier gas is transferred to the oxidation reaction section, where carbon dioxide based on only the volatile organic substances contained in the carrier gas is generated, and this is detected by the carbon dioxide detection section.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

(F) Example FIG. 1 is a structural explanatory view of one example of the total organic carbon (TOC) analyzer of the present invention. In this figure, TOC analyzer
(1) is a carrier gas supply section (2), a total carbon (TC) reaction section
(3), inorganic carbon (IC) reaction part (4) and carbon dioxide detection part
An analysis channel (a) that connects (5) in this order, a bypass channel (b) that connects the carbon dioxide absorption section (6) and the oxidation reaction section (7) in this order, and a calculation section (8) mainly It is configured.

The carrier gas supply unit (2) has an air cylinder (21), a flow control valve (22) and a flow meter (23).

The TC reaction section (3) is a quartz TC combustion tube (inner diameter 14 mm, outer diameter 16 mm, length 250 m) with a sample injection port (33) provided in the upper part.
m) (31) and a high temperature heating furnace (32) for heating the combustion pipe (31)
It has and. The combustion tube (31) is filled with a platinum catalyst supported on granular alumina having a diameter of 2 to 3 mm as an oxidation catalyst (34).

The IC reaction section (4) includes an IC reaction tube (Pyrex tube having an inner diameter of 14 mm, an outer diameter of 16 mm, and a length of 60 mm) (41) provided with a sample injection port (43) on the upper part thereof, and the reaction tube (41). Low temperature heating furnace for heating
(42) and are provided. In the reaction tube (41), a strongly acidic ion exchange resin (Amberley 12) is used as an IC reaction catalyst (44).
0B) is filled.

The carbon dioxide detector (5) is a non-dispersive infrared analyzer having a detector that detects a change in the concentration of carbon dioxide contained in the carrier gas as a change in the microphone capacitor capacity, a sample cell, a comparison cell, and a light source ( NDIR) (51).

Carbon dioxide absorber (6) has an inner diameter of 12 mm, an outer diameter of 15 mm, and a length of 80 m.
A column in which lithium hydroxide is filled as a carbon dioxide absorbent in an absorption tube (61) made of glass of m is used.

The oxidation reaction part (7) is a quartz combustion tube (inner diameter 8 mm, outer diameter 10 m
m, length 200 mm) (71) and a high temperature heating furnace (72) for heating the combustion tube (71). The combustion tube (71) is filled with a platinum catalyst as an oxidation catalyst (73).

A calculation unit (8) is connected to the carbon dioxide detection unit (5). The calculation unit (8) includes a calculation unit (81), a storage unit (82) and a display unit (83).

The bypass flow path (b) has an IC reaction part (4) and a carbon dioxide detection part.
It is connected to the analysis channel (a) between (5) and the solenoid valves (c) and (d).

Next, the operation of the TOC analyzer (1) will be described.

(I) When measuring TOC, set the solenoid valves (c) and (d) to the a side, respectively, and set the carrier gas supply section (2) → TC reaction section (3) → IC reaction section (4) → carbon dioxide. The TOC measurement analysis flow path (a) is formed so that the detection unit (5) communicates in this order. After that, the flow rate control valve (22) and flow meter (23) are adjusted so that high-purity air is transferred from the carrier gas supply unit (2) to the analysis flow path at a predetermined flow rate (for example, about 150 m / min). , High temperature heating furnace (32) internal temperature to 680 ℃, low temperature heating furnace
(42) Set the internal temperature to 120 ℃ and perform conditioning. After that, the sample injection port (33) of the TC reaction part (3)
By injecting a more predetermined amount of sample, carbon dioxide derived from all carbon contained in this sample is measured by the carbon dioxide detector (5), and as a result, it is obtained as a TC value from the calculator (8). . Next, by injecting the same amount of the same sample from the sample injection port (43) of the IC reaction part (4), the carbon dioxide derived from the inorganic carbon contained in this sample is detected by the carbon dioxide detection part (5). And the result is obtained as an IC value from the calculation unit (8). The TOC value is calculated by further subtracting from these results in the calculation unit (8).

(ii) The case of measuring volatile organic carbon (POC or VOC) will be described.

・ In the case of POC measurement, set the solenoid valves (c) and (d) to the low side and set the carrier gas supply section (2) → TC reaction section (3).
→ IC reaction part (4) → Carbon dioxide absorption part (6) → Oxidation reaction part
(7) → Form a flow path that connects the carbon dioxide detector (5) in this order. After that, high-purity air is supplied from the carrier gas supply unit (2) to the analysis channel at a predetermined flow rate (for example, about 150 m /
flow rate control valve (22) and flow meter
Conditioning is performed in (23), and conditioning is performed in a state where the temperature in the high temperature heating furnace (72) of the oxidation reaction part (7) is set to 680 ° C. After that, by pouring a predetermined amount of sample from the sample injection port (43) of the IC reaction part (4), the POC component and the dissolved carbon dioxide contained in this sample are separated from the IC reaction part.
At (4), the carrier gas is purged to be taken out from the sample, and these gases are contained in the carrier gas and transferred to the carbon dioxide absorption section (6). In the absorption part (6), after the dissolved carbon dioxide is absorbed and removed from the carrier gas, transferred to the oxidation reaction part (7) heated to a predetermined temperature,
In the reaction section (7), the POC component contained in the carrier gas is converted into carbon dioxide. Carbon dioxide derived from this POC is measured by the carbon dioxide detector (5), and the PO is calculated by the calculator (8).
It will be obtained as a C value. The drain drain valve is opened after each measurement to drain the accumulated drain.

In the case of VOC measurement, first, the POC value is measured in the same manner as above. After that, the low temperature heating furnace (4
2) Conditioning is performed in the same manner as the POC measurement, except that the internal temperature is set to a temperature at which the VOC component vaporizes (for example, about 120 ° C.). After that, by injecting the sample from the sample injection port (43) of the IC reaction part (4), the VOC component and the dissolved carbon dioxide contained in this sample are I
The sample is taken out from the sample by heating in the C reaction section (4) and purging of the carrier gas, and these gases are contained in the carrier gas and transferred to the carbon dioxide absorption section (6). In the absorption part (6), after the dissolved carbon dioxide is absorbed and removed from the carrier gas, it is transferred to the oxidation reaction part (7) heated to a predetermined temperature and contained in the carrier gas in the reaction part (7). The VOC component is converted into carbon dioxide. Carbon dioxide derived from VOC is measured by the carbon dioxide detector (5) and obtained as a VOC value by the calculator (8).

According to the TOC analyzer described above, not only TOC but also POC in this TOC can be measured. Furthermore, only a predetermined VOC in the TOC can be measured.

In addition, in the above VOC measurement, IC is used to vaporize the VOC component.
Although the low temperature heating furnace (42) of the reaction section (4) was used, the heating furnace (42) was stopped in addition to this, and the carrier was generated by heating the high temperature heating furnace (32) of the TC reaction section (3). It is also possible to heat the gas to a predetermined temperature and vaporize the VOC component by the heated carrier gas.

(G) Effect of the Invention According to the present invention, it is possible to measure only the low-boiling point organic carbon of the total organic carbon in the sample with one simple total-organic-carbon analyzer.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of one embodiment of the total organic carbon analyzer of the present invention. (2) …… Carrier gas supply section, (3) …… All carbon reaction section, (4) …… Inorganic carbon reaction section, (5) …… Carbon dioxide detection section, (6) …… Carbon dioxide absorption section, (7) …… Oxidation reaction part, (8) …… Calculation part, (21) …… Air cylinder, (22) …… Flow control valve, (23) …… Flowmeter, (31) …… TC combustion tube , (32), (72) …… High temperature heating furnace, (33) ， (43) …… Sample inlet, (34) ， (73) …… Oxidation catalyst, (41) …… IC reaction tube, ( 42) …… Low temperature heating furnace, (44) …… IC reaction catalyst, (51) …… Non-dispersive infrared analyzer, (a) …… Analysis channel, (b) …… Bypass channel (c ) 、 (D) …… Solenoid valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirofumi Miura, Hirokazu Miura, No. 1, Kuwabara-cho, Nishinokyo, Nakagyo-ku, Kyoto, Kyoto Prefecture Sanjo Factory Sanjo Factory (56) References JP-A-61-82162 (JP, A) JP-A-SHO 62-190465 (JP, A)

Claims (1)

[Claims] 1. An all-organic carbon analyzer comprising an analysis flow path connecting a carrier gas supply section, a total carbon (TC) reaction section, an inorganic carbon (IC) reaction section and a carbon dioxide detection section in this order, An oxidation reaction part having a carbon dioxide absorption part and a heating means is provided in this order between the IC reaction part and the carbon dioxide detection part, and a carbon dioxide is removed from a carrier gas containing an organic substance volatilized or vaporized in the IC reaction part. A total organic carbon analyzer characterized in that a bypass flow path that can oxidize and vaporize the volatile or vaporized organic matter after absorbing and removing carbon and transfer it to the carbon dioxide detecting section is switchably provided.