JPH08101187A - Measuring device for organic carbon with volatility - Google Patents

Abstract

PURPOSE: To provide a volatile organic carbon measuring device which can measure POC precisely. CONSTITUTION: A specimen TP supplied to a specimen sparge vessel 1 from a specimen vessel 4 by an injector 2 and a rotary valve 3 is subjected to bubbling with a carrier gas, and the POC component of the specimen TP is gasified in the unchanged state, while a part of the whole of the inorganic carbon component(s) is turned into carbon dioxide gas, which flows into flow paths I, II in equal quantity via a distributer 5. The gas having flowed to the flow path I is combusted in a POC combusting tube 7 so that the POC component in the gas is turned into carbon dioxide gas and supplied to one of the cells in a non-dispersive infrared gas analyzer 8 of comparative flow type, while the other portion of gas which has flowed to the flow path II is supplied in the unchanged state to the other cell of the gas analyzer 8. This gas analyzer 8 of comparative flow type senses the difference between the carbon dioxide amounts passing through the two cells, and a signal processing means 9 calculates the POC amount in the specimen TP processing the sensed signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon content measuring apparatus mainly used for measuring the quantity of organic carbon contained in water such as water and sewage water, water for various plants, and water in rivers,
In particular, it relates to a device for measuring the amount of volatile organic carbon.

[0002]

2. Description of the Related Art In recent years, organic carbon (O) contained in water such as water and sewage water, water for various plants, water in rivers, etc.
The need for measuring C) is increasing, and the measurement of volatile organic carbon (Purgeable OC (hereinafter referred to as “POC”)) is also one of the important items in pollution investigations.

Conventionally, the following two methods have been adopted for such POC measurement.

First, in the first method, sample water is bubbled with a carrier gas, and among the POC gas extracted into the carrier gas at this time and carbon dioxide converted from inorganic carbon (IC), Carbon dioxide (CO2) is adsorbed using an alkaline substance such as lithium hydroxide (LiOH),
After the removal, the remaining POC gas was burned to convert it into carbon dioxide, and then the amount of this carbon dioxide was measured with a gas analyzer or the like to measure the amount of POC.

In the second method, the sample water is bubbled with a carrier gas, and the POC gas extracted in the carrier gas at this time and the carbon dioxide converted from inorganic carbon (IC) are POC. The POC gas is trapped by using an adsorbent such as a molecular sieve, and after the carbon dioxide converted from the inorganic carbon has completely passed through, the temperature is raised to desorb the POC from the trap and burn it. The amount of POC was measured by measuring the amount of this carbon dioxide with a gas analyzer or the like after converting it to carbon dioxide.

[0006]

However, in the first method, depending on the POC component, such as when the POC contains an ester, the POC itself may be an alkaline substance such as lithium hydroxide (LiOH). Therefore, a negative error may be given in the measurement of POC.

In the second method, depending on the POC component such as a low molecular weight compound, all the POC
May not be completely adsorbed by the POC adsorbent, so that a negative error may be given in the POC measurement as in the case of the first method. Further, in the second method, the operation of raising and lowering the temperature of the POC adsorbent is required, so that the measurement takes a long time.

Therefore, the present invention provides a volatile organic carbon measuring apparatus capable of accurately measuring the POC in a sample in order to solve such a problem.

[0009]

In order to achieve the above object, the volatile organic carbon measuring apparatus according to the present invention holds a sample solution and blows an extraction gas to remove the volatile organic carbon in the sample solution. A bubbling means for vaporizing, and a combustion means for burning volatile organic carbon, by burning the gas from the bubbling means, a first flow path for converting the volatile organic carbon component into carbon dioxide gas, Volatile organic carbon in the sample based on the amount of carbon dioxide in the gas supplied from each of the first flow path and the second flow path and the second flow path that allows the gas from the bubbling means to pass through as it is. And a measuring means for measuring the amount of.

[0010]

The operation of the present invention will be described with reference to FIG. 1. The sample TP supplied from the sample container 4 to the sample sparge container 1 by the sample injector 2 and the rotary valve 3 is bubbled by the carrier gas, The POC component is vaporized as it is, and a part or all of the inorganic carbon component is converted into carbon dioxide gas and flows into the flow passages I and II via the distributor 5 in equal amounts. The gas flowing through the flow path I is burned in the POC combustion tube 7, the POC component in the gas is converted into carbon dioxide gas, and the COC gas is supplied to one cell of the non-dispersive infrared gas analyzer 8 of the comparative flow type. Along with the flow path
The gas flowing in II is directly supplied to the other cell of the non-dispersion type infrared gas analyzer 8. Then, the comparison flow type non-dispersion type infrared gas analyzer 8 detects the difference in the amount of carbon dioxide passing through both cells, and the signal processing means 9 processes the detected signal, thereby the amount of POC in the sample TP. To calculate.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows an example of a volatile organic carbon measuring apparatus according to the present invention. Reference numeral 1 is a glass sample sparging container, in which a sample TP is accommodated, and then a carrier gas such as high-purity air is supplied from below. Bubbling of the sample TP by blowing, vaporize the POC component in the sample TP,
Along with this, part or all of the inorganic carbon component is converted to carbon dioxide. The carrier gas 2 such as high-purity air is configured to be supplied in a fixed amount from a cylinder or the like (not shown).

Reference numeral 2 denotes a sample injector, which inhales a predetermined amount of the sample TP held in the sample container 4 through the rotary valve 3,
After that, the rotary valve 3 is switched to deliver the sample TP sucked into the sample sparge container 1.

Reference numeral 5 denotes a distributor, which distributes the POC gas and carbon dioxide gas vaporized in the sample sparge container 1 to the flow paths I and II in equal amounts. A POC combustion tube 7 made of, for example, quartz glass having an oxidation catalyst such as platinum filled therein is connected to the flow path I in the middle thereof.
The C combustion tube 7 is heated by the electric furnace 6 arranged around it. Therefore, of the gas that has passed through the flow path I, its POC component is burned when passing through the POC combustion tube 7 and converted into carbon dioxide gas, and one of the non-dispersive infrared analyzers 8 of the comparative flow type. Supplied to the cell. On the other hand, the gas passing through the flow path II is directly supplied to the other cell of the non-dispersive infrared analyzer 8 of the comparative flow type.

Reference numeral 8 is a comparative distribution type non-dispersive infrared analyzer, which is a relative value of the amount of carbon dioxide supplied to one cell to the amount of carbon dioxide supplied to the other cell, that is, the detected amount of both. The difference is output as a signal. In the case of the present embodiment, the amount of carbon dioxide supplied from the flow path I (the amount of POC component and the inorganic carbon component) with respect to the amount of carbon dioxide supplied from the flow path II (the amount of carbon dioxide indicating the inorganic carbon component). Is configured to output a signal indicating a relative value of (amount of carbon dioxide indicating the sum of). 9 is a signal processing means,
Based on the difference signal of carbon dioxide from the non-dispersive infrared analyzer 8 of the comparative flow type, the POC amount in the sample TP is calculated by a known method.

Next, the operation of the above embodiment of the present invention will be described with reference to FIG. In the figure, the sample TP supplied from the sample container 4 to the sample sparge container 1 by the sample injector 2 and the rotary valve 3 is bubbled by the carrier gas, the POC component in the sample TP is vaporized as it is, and the inorganic carbon component Some or all of this is converted to carbon dioxide gas. Here, the vaporized POC gas and carbon dioxide gas reach the distributor 5 and are distributed to the flow paths I and II in equal amounts.

Here, the gas flowing through the flow path I is the PO
When the C component passes through the POC combustion pipe 7, it is burned and converted into carbon dioxide gas, but the carbon dioxide gas converted from the inorganic carbon component passes through the POC combustion pipe 7 as it is, and the non-comparative type It is supplied to one cell of the dispersion type infrared analyzer 8. Further, the gas flowing through the flow path II passes through the flow path II as it is and is supplied to the other cell of the non-dispersion type infrared gas analyzer 8.

The non-dispersive infrared analyzer 8 detects the relative value of the amount of carbon dioxide supplied to the other cell to the amount of carbon dioxide supplied to the other cell, that is, the difference between the detected amounts of the two. Then, the signal is output to the signal processing means 9. Here, the amount of carbon dioxide supplied from the channel I corresponds to the sum of the amounts of the POC component and the extracted inorganic carbon component in the sample TP, and the amount of carbon dioxide supplied from the channel II is Since it corresponds only to the amount of the inorganic carbon component extracted from the sample TP, the difference signal between the amounts of carbon dioxide in both channels shows a value corresponding to the amount of the POC component in the sample TP. The signal indicating the amount of carbon dioxide corresponding to the amount of the POC component output from the non-dispersive infrared analyzer 8 is actually subjected to well-known signal processing in consideration of a chemical reaction in the middle in the signal processing means 9, and is actually The POC amount of is calculated.

FIG. 2 is a diagram showing a second embodiment of the volatile organic carbon measuring apparatus according to the present invention. The basic structure is the same as that of the embodiment of FIG. Then, the three-way solenoid valve 5 ′ for switching and supplying the gas from the sample sparge container 1 to the flow path I and the flow path II is replaced with a non-dispersive infrared analyzer 8 of a comparative flow type, and a reference is made to one cell. The only difference is that a reference non-dispersive infrared analyzer 8'in which a gas is sealed is used.

The operation of the second embodiment of the present invention will be described with reference to FIG. First, set the three-way solenoid valve 5'to the flow path I.
In the state of switching to the side, a fixed amount of the sample TP is supplied from the sample container 4 to the sample sparge container 1 by the sample injector 2 and the rotary valve 3, and the carrier gas is bubbled. As a result, the POC component in the sample TP is vaporized as it is, part or all of the inorganic carbon component is converted into carbon dioxide gas, and these gases flow into the flow path I via the three-way solenoid valve 5 ′.

The POC component of the gas flowing through the flow path I is burned in the POC combustion pipe 7 and converted into carbon dioxide gas. The carbon dioxide gas converted from the inorganic carbon component is P
After passing through the OC combustion tube 7 as it is, the amount of carbon dioxide supplied to the cell of the non-dispersion type infrared gas analyzer 8'is detected.

Next, the three-way solenoid valve 5'is switched to the flow path II side, the sample injector 2 and the rotary valve 3 supply the same amount of the sample TP from the sample container 4 to the sample sparge container 1 as before, and again. Bubble with carrier gas. As a result, the POC component in the sample TP is vaporized as it is,
Part or all of the inorganic carbon component is converted into carbon dioxide gas, and these gases are flowed through the three-way solenoid valve 5 '.
Pour into II. Then, the gas flowing in the flow path II passes through the flow path II as it is, is supplied to the cell of the non-dispersion type infrared gas analyzer 8 ', and the amount of carbon dioxide is detected. After the difference between the two detected signals is taken by the signal processing means 9,
The predetermined signal processing is performed, and the POC amount contained in the sample TP is obtained as in the case of FIG.

As described above, according to the present invention, the situation in which some POCs are lost in the conventional process for detecting POCs does not occur, so the amount of POCs in a sample can be reliably and accurately determined. It can be measured. In particular, the first embodiment of the present invention has an advantage that the measurement time can be shortened because the bubbling gas can be flowed in the flow passage I and the flow passage II at the same time, and the second embodiment of the present invention can be performed. In the example, since the separately bubbled gas is flowed in the flow paths I and II, the measurement time is longer than that in the first embodiment, but the gas flowing in the flow paths I and II is more accurately measured. Therefore, the detection accuracy of the POC amount is improved.

In the above-mentioned embodiment, when a small amount of acid such as hydrochloric acid is added to the sample TP and the pH of the sample TP is set to 3 to 4 or less and the measurement is performed, the inorganic substance is not bubbled during bubbling in the sample sparge container. Since the extraction of carbon IC is carried out quickly and completely, it becomes possible to measure the amount of inorganic carbon IC from the measurement using the channel II in the second embodiment. However, for the purpose of measuring the POC amount only, the addition of acid is not particularly required.

[0025]

As described above, according to the present invention, since a situation in which a part of POC is lost during the process of detecting POC does not occur, the amount of POC in a sample can be measured reliably and accurately.

[Brief description of drawings]

FIG. 1 is an example of a volatile organic carbon measuring device according to the present invention.

FIG. 2 is another embodiment of the volatile organic carbon measuring device according to the present invention.

[Explanation of symbols]

 1 ・ ・ Sample sparging container 2 ・ ・ ・ ・ ・ ・ Sample injector 3 ・ ・ ・ ・ ・ ・ Rotary valve 4 ・ ・ ・ ・ ・ ・ Sample container 5 ・ ・ ・ ・ ・ ・ Distributor 6 ・ ・··· Electric furnace 7 ··· POC combustion tube 8 ··· Comparative flow type non-dispersive infrared analyzer 9 ··· Signal processing means

Claims (1)

[Claims] 1. A gas from the bubbling means, comprising a bubbling means for holding the sample solution and vaporizing the volatile organic carbon in the sample solution by blowing an extraction gas, and a combustion means for burning the volatile organic carbon. A first flow path for converting the volatile organic carbon component into carbon dioxide gas by burning the second flow path, a second flow path for allowing the gas from the bubbling means to pass therethrough, and the first flow path. A measuring device for measuring the amount of volatile organic carbon in a sample from the amount of carbon dioxide in the gas respectively supplied from the second flow path, and a volatile organic carbon measuring device.