JPS6188150A - Instrument for measuring concentration of component to be oxidized in water - Google Patents

Abstract

PURPOSE:To measure the concn. of an extremely slight amt. of the component to be oxidized in water with a low-sensitivity gas analyzer by accumulating the intended component in gas in an annular flow passage to increase the concn. of said component. CONSTITUTION:The sample water introduced into a combustion furnace 3 by a sample water introducing mechanism 4 is burned. The gas flowing out of the combustion furnace passes through the 1st pipeline 21 and is introduced into the gas analyzer 10, by which the concn. of the intended component is measured. The gas flowing out of the gas analyzer passes through the 2nd pipeline 22 and is introduced into the combustion furnace. A gas circulating mechanism 24 circulates the gas to the annular flow passage 23 consisting of the 1st pipeline, the gas analyzer and the 2nd pipeline. A calculator 25 calculates the difference between the output signal of the gas analyzer when the sample water is not introduced into the combustion furnace and the output signal of the gas analyzer when the sample water is introduced into the combustion furnace. Then the intended component in the gas flowing into the gas analyzer is accumulated eventually in the annular flow passage at every introduction of the sample water into the combustion furnace.

Description

Detailed description of the invention [Technical field to which the invention pertains] The present invention burns oxidizable components such as organic or inorganic carbon and nitrogen in water together with a carrier gas to form gaseous oxides, and produces combustion exhaust gas. A device for measuring the oxidizable component AI in water by measuring the concentration of the oxides in the water using a gas analyzer, especially for extremely low concentrations of oxidizable components in water, such as carbon components in water used in semiconductor manufacturing equipment. The present invention relates to an apparatus configuration capable of measuring the concentration of a chemical component using a relatively low-sensitivity gas analyzer.

[Prior art and its problems]

Figure 4 shows the total amount of organic and inorganic carbon in water (TC
) This is an example of the configuration of a conventional water carbon concentration measurement device that measures the concentration.
A sample pump 4 is a sample water introducing mechanism consisting of a sample water tank 1 and a sample pump 2. The combustion furnace 3 is separated into a first chamber 3a and a second chamber 3b by a partition wall 3c,
Both chambers are maintained at a temperature of approximately 900° C. by a heating device and temperature controller 5 (not shown). The sample water 1a introduced into the first chamber 3a of the combustion furnace is injected with a carrier gas 6 which contains no carbon dioxide (CO2) and contains oxygen near the inlet point of the chamber. Sample 1
If organic or inorganic carbon is contained in the gas-liquid mixture thus formed, these carbons are prepared in the first chamber 3a of the combustion furnace. It is combusted by the action of the catalyst and combined with oxygen in the carrier gas 6 to become CO2 gas. Therefore, from the first chamber 3a of the combustion furnace, a mixed gas of CO and gas produced in this way, the vapor of the sample water 1, and the carrier gas 6 is discharged. The condenser 8 is a drain pot that removes the moisture generated in the condenser 7 and seals the gas flow path. 10, here CO
2 times are measured. Reference numerals 11 and 12 are a dust filter and a flow meter for monitoring the gas flow rate attached to the gas inflow pipe of the gas analyzer 10. Reference numeral 13 denotes a carrier gas pump that introduces outside air 14 containing oxygen such as air into the second chamber 3b of the combustion furnace 3. When the outside air 14 is introduced into the second chamber 3b by the pump 13, organic Or, if inorganic carbon is included, these carbons are converted into CO,
Gasunko is converted. 15 is the CO2 generated as described above in the gas flowing out from the second chamber 3b and the outside air 14.
Middle: A CO2 absorber that absorbs both the CO2 that has been included since the beginning and generates and releases carrier gas 6. 16 is a water carbon concentration measuring device consisting of the above-mentioned parts.

Since the carbon concentration measuring device 16 is configured as described above, the carrier gas 6 introduced into the combustion furnace WJl chamber 3a contains oxygen but does not contain carbon, and as a result, the gas The output signal of the analyzer 10 is the sample water 1
The value corresponds to the amount of carbon contained in a, and when the sample water 1a or the combustion furnace 3a is injected in batches, the output signal is in the form of a pulse whose height corresponds to the amount of carbon contained in the sample water 1a or the combustion furnace 3a. When the sample water 1a is continuously injected into the combustion furnace 3a, the sample water 1a has a flat shape with a height corresponding to the amount. Pressure combustion furnace 3a
The body of sample water 1a that is exposed to K! By controlling R, the total carbon concentration in the sample water la is measured from the output signal of the gas analyzer 10. In the measuring device 16, the gas analyzer 1
Is it possible to release the gas emitted from 0 to the atmosphere, to prevent measurement errors caused by incomplete combustion of carbon in the second chamber 3b of the fuel furnace, or to update the CO1 absorber in the CO□ absorption field 15? Because the period is long, the gas discharged from the gas analyzer 10 is introduced into the gas inlet of the CO2 absorber 15, and the pump 13 and the combustion furnace second chamber 3b' are omitted. A device for determining the concentration of traces of backing material is also known (see Japanese Patent Publication No. 53-47197).

The above-mentioned M determination device 16 is used to measure the concentration of total carbon (TC) in water. It is clear that the concentration of total organic carbon (TOO) in water can be measured by the measuring device f?ff116.

Conventional water carbon 1 mm measuring device Measures as described above, so when the water carbon concentration becomes low, CO in the exhaust gas led to the gas analyzer 10! Naturally, the concentration will also be lower, and if you try to measure TOO 9 degrees or Te 3 degrees of ultrapure water with TOCa degrees ppb to several tens of ppb to several dozen I) b used in a conductor manufacturing device using a method like measuring device 16. , the concentration of CO in the exhaust gas guided to the gas analyzer 10 becomes a minute value.

However, in the conventional water carbon concentration measuring device 16, a non-dispersive infrared absorption analyzer is usually used as the gas analyzer 10, and the minimum measurement range of this is 0 to 50 pp.
Therefore, there is a problem in that conventional water carbon concentration measuring devices using such gas analyzers cannot measure trace amounts of carbon.

[Purpose of the invention]

The present invention solves the problems of the above-mentioned underwater carbon concentration measuring device, and measures the minute concentration of oxidizable components such as organic or inorganic carbon and nitrogen contained in water using a method that has not been widely used in the past. An object of the present invention is to provide an apparatus for measuring the concentration of oxidizable components in water that can be measured using a relatively low-sensitivity gas analyzer.

[Key points of the invention]

In order to achieve the above-mentioned objects, the present invention provides a combustion furnace for burning sample water; a sample water control mechanism for introducing sample water into the combustion furnace; and a part of target components in the introduced gas. a gas analyzer for measurement; a first pipe line for introducing the gas flowing out from the combustion furnace to the gas analyzer; a line for guiding the gas flowing out from the gas analyzer to the combustion furnace; a supply line for introducing outside air into the annular flow path; A gas mechanism; and a calculator that calculates the difference between the output signal of the gas analyzer when no sample water is introduced into the combustion furnace and the output signal of the gas analyzer when sample water is introduced into the combustion furnace. This is an oxidizing component W measurement device that measures the concentration of oxidizable components in sample water based on the output signal of a computing unit. With this configuration, sample water is introduced into the combustion furnace. Each time the target component in the gas flowing into the gas analyzer is accumulated in the annular flow path, the concentration of the component increases.
The present invention provides a measuring device capable of measuring extremely small concentrations of oxidizable components in water even by using relatively low-sensitivity gas analyzers that have been widely used in the past.

[Embodiments of the invention]

Figure 1 is a configuration diagram of an embodiment of the present invention, and in the figure, the combustion furnace 3 is composed of only a first chamber 3a.

17 is a drain valve that drains water accumulated in the drain pot 8;
18 is the gas outlet 8a of the drain pot 8 and the circulation pump 1
a valve configured to open and close a pipeline between the inlet 19a of the
20 is an outside air valve that guides the outside air 14Y to the pump port 19a. The outlet 19b of the circulation pump 19 is connected to the gas port 11a of the filter 11. In the figure, a condenser 7, a drain pot 8, a valve 18, a pump 19. Filter 11. The flow rate analyzer 10 is configured so that four people can use it.

Reference numeral 21 is a first pipe line which is composed of a condenser 7, a drain pot 8, a filter 11, a flow meter 12, and pipes connected to them, and introduces gas flowing out from the combustion furnace 3 into the gas analyzer 10. Reference numeral 22 denotes a second pipe line for introducing the gas flowing out from the gas analyzer 10 into the combustion furnace 3, and the second pipe line 22 includes:
In this case, the gas guided by this pipe and the sample water 1a
The sample water is heated in a combustion furnace 3 in order to mix well.
Connected to sample water piping near the population. In FIG. 1, each part is configured as described above, so when the drain valve 17 and the outside air valve 20 are closed and the valve 18 is opened and the pump 19 is operated, gas flows through the first pipe line 21 and the gas analyzer 10. The annular flow path 23'Y consisting of the second pipe line 22 and the combustion furnace 3 circulates. 24 is a valve 18 that circulates gas in the annular flow path 23;
and a pump 19, and 25 is a computing unit that performs arithmetic operations as will be described later on the output signal 10a of the gas analyzer 10.

In the measuring device shown in FIG. 1, first, valve 18' is closed, valves 17 and 20 are opened, and pump 19 is operated. Then, the outside air 14 flows through the valve 20, the pump 19, the filter 11, and the flow meter 1.
2. Gas analyzer lO1 The gas flows through the second pipe line 22, the combustion furnace 3, the condenser 7, the drain pot 8, and the valve 17 in order, and the gas in this flow path is replaced with outside air 14. As a result, when the outside air 14 is air, the output voltage of the gas analyzer IO becomes as shown by the characteristic line between AB in FIG. 2. This output voltage corresponds to a CO and gas concentration of about 300 ppm. Next, leave the operation of the pump 19 as it is, and close the °C valve 18" and the valves 17 and 20.

As a result, the outside air 14 trapped in the annular flow path 23 is circulated through the flow path 23 by the gas circulation mechanism 24. At this time, as mentioned above, if the circulating outside air 14 contains carbon components, this carbon will be burned in the combustion furnace 3 and CO and gas will be generated, so the output voltage of the gas analyzer 10 will increase by one degree. However, as the outside air 14 circulates through the annular flow path 23, all the carbon components are burned out, and the gas analyzer 1 finally
An output voltage of 0 saturates. The characteristic line between B and 0 in FIG. 3 represents this pattern 1. Ec is the output voltage of the analyzer in this saturated state. The sample water 1a is then continuously introduced into the combustion furnace 3 by the introduction mechanism 4 while the pump 19 continues to operate. As a result, in the combustion furnace 3, the amount of carbon corresponding to the total amount of carbon contained in the introduced sample water 1a is
O2 gas is generated, and the amount of this gas generated increases as the sample water 1a is introduced into the combustion furnace 3. Therefore, at this time, the output voltage of the gas analyzer 10 increases as time passes, as shown by the characteristic line C-9 in FIG. In Fig. 2, Tc and Td are the times corresponding to points C and D on the characteristic line, Ed is the output voltage at time Td, and the difference voltage E
d-E c corresponds to the cumulative amount of total carbon (TC) introduced into the combustion furnace 3. Therefore, sample water 1aY combustion furnace 3
When the sample water is introduced for a predetermined time period ΔT at a constant instantaneous flow rate q, from the value of the differential voltage Ed-Ec, the sample water is The total carbon concentration in 1a can be measured. In the above, the flow rate q was controlled to a constant value, but if the sample water 1aft is finally introduced into the combustion furnace 3 by q・ΔT, the sample water flow rate can be controlled to a constant qK.
It is clear that there is no need to control it. In other words, the sample water 1a may be manually injected into the combustion furnace 3 using silydine or the like.

As mentioned above, in order to perform the determination using the differential voltage Ed-Ec, the differential pressure indicated by the gas analyzer 10 must be of a significant magnitude. If the sample water 1a is simply introduced into the short-time combustion furnace 3, the differential voltage E d - E c is less than the minimum sensitivity of the analyzer 10, so it cannot be discriminated, or the total carbon Ed-E if the amount is integrated
c becomes a distinguishable size. Time ΔT shown in m2 diagram
Alternatively, the total flow rate q・ΔT mentioned above is the difference voltage Ed−Ec
It is a predetermined time set such that the value becomes a distinguishable size, and is a predetermined total amount of elements. The computing unit 25 in FIG. 1 calculates the output voltage h i c of the combustion furnace 3 in FIG.
The output signal of the gas analyzer 10 when the sample water 1a is not introduced into the combustion furnace 3 is memorized, and this signal and the gas when the sample water 1a is introduced into the combustion furnace 3, such as the output voltage Ed in FIG. This is an arithmetic unit that calculates the difference F, dEc from the output signal of the analyzer 10. In Figure 1, valves 17, 18, 20
Although the pump 2.19 and the computing unit 25 are each manually operated, they may also be sequentially controlled by a control device. 27 injects the acid bath g, 29 stored in the container 28 into the drain pot) 8tC accumulated water to lower the pt-t of this water, and as a result, the C(J, gas generated in the combustion furnace 3) is poured into the drain pot. 8 is a solution pump that does not dissolve in the condensed water, thereby preventing errors in measuring the total carbon concentration, and 30 is an underwater carbon concentration meter consisting of the above-mentioned parts shown in Figure 1. The measuring device 30 performs the Ed-Ec test as described above.
When the calculation is completed and a series of concentration measurement operations are completed, the valve 18 is closed, the valves 17 and 20 are opened, and the pump 19 pumps outside air 14.
The next concentration measurement cycle is started by introducing 1- into the annular channel 23. Since the outside air valve 20 is used as described above, it is an air supply mechanism that introduces the outside air 14 into the annular flow path 23.

Fig. 3 is a block diagram of the second embodiment of the present invention.The main difference from Fig. 1 is that when the level of condensed water is not at a predetermined position, all condensed water is automatically removed from the drain pot 8. By providing the drain discharge pipe 31 for discharging water, and as shown in the figure, the valves 18 and 20 are provided in the first pipe line 21 between the combustion furnace 3 and the condenser 7, unlike in FIG. There is no problem. 32 converts the gas in the annular flow path 23 to outside air 1
This is the exhaust valve used when ventilating at 4.

Figure 4 shows that by removing inorganic carbon in the sample water in advance, it is possible to measure 4 degrees of total qualitative carbon (TQC) using the measurement equipment shown in Figures 1 and 3L. This is the same as the case of the conventional total carbon concentration) j + lj constant fission i shown in . Furthermore, in each of the embodiments described above, the outside air 14
Although air is shown as an example, the outside air 14 may be pure oxygen. Furthermore, although the carbon concentration measuring device has been described in detail above, it goes without saying that the present invention is also applicable to oxidizable components such as nitrogen that can be oxidized in the combustion furnace 3. it is obvious. In the case of a nitrogen concentration measuring device, a nitrogen oxide analyzer is naturally used as the gas analyzer 10.

〔Effect of the invention〕

As described above, the present invention includes a combustion furnace that burns sample water; a sample water introduction mechanism that introduces the sample water into the combustion furnace; and a gas analyzer that measures the concentration of the target component in the introduced gas. A first pipe line that introduces the gas flowing out from the combustion furnace into the gas analyzer; A second pipe line introducing the gas flowing out from the gas analyzer into the combustion furnace; The combustion furnace, the first pipe line, and the gas analysis a gas circulation mechanism that circulates gas through an annular flow path consisting of a meter and a second pipe; an air supply mechanism that introduces outside air into the annular flow path; and an output of the gas analyzer when no sample water is introduced into the combustion furnace. An arithmetic unit that calculates the difference between the signal and the output signal of the gas analyzer when the sample water is introduced into the combustion furnace constitutes an apparatus for measuring the concentration of oxidizable components in water. Since the oxidizable components are measured at 00 degrees, this configuration ensures that the target components in the gas flowing into the gas analyzer enter the annular flow path every time sample water is introduced into the combustion furnace. As a result of the accumulation and increase in the concentration of these components, it is possible to obtain a measuring device that can measure the concentration of extremely small amounts of oxidizable components in water, even using relatively low-sensitivity gas analyzers that have been widely used in the past. There is.

[Brief explanation of drawings]

Figures 1 and 3 are configuration diagrams of different embodiments of the present invention, Figure 2 is an explanatory diagram of changes over time in the output voltage of the gas analyzer in Figure 1, and Figure 4 is a conventional water carbon concentration measuring device. FIG. 1a...Sample water, 3...Combustion furnace, 4.
... Sample water introduction mechanism, 10 ... Gas analyzer, 14 ... Outside air, 20 ... Outside air valve as air supply mechanism, 21 ...・・First conduit, 22・・
...Second pipe line, 23...Annular flow path, 24.
...Gas circulation mechanism, 25...Arithmetic unit. Seagull 1 Figure 12 Figure 3 Figure 14

Claims (1)

[Claims] 1) A combustion furnace that burns the introduced sample water; A sample water introduction mechanism that introduces the sample water into the combustion furnace; A gas analyzer that measures the concentration of a target component in the introduced gas; The combustion furnace a first pipe line for introducing gas flowing out from the gas analyzer into the gas analyzer; a second pipe line introducing gas flowing out from the gas analyzer into the combustion furnace; the combustion furnace, the first pipe line, and the a gas circulation mechanism that circulates gas through an annular flow path consisting of a gas analyzer and the second pipe; an air supply mechanism that introduces outside air into the annular flow path; and when the sample water is not introduced into the combustion furnace. a calculator for calculating the difference between the output signal of the gas analyzer and the output signal of the gas analyzer when the sample water is introduced into the combustion furnace; An apparatus for measuring the concentration of oxidizable components in water, which measures the concentration of oxidizable components in water.