JPH0232255A - Instrument for measuring organic carbon - Google Patents

Abstract

PURPOSE:To prevent the measurement error by an inadequate carrier gas flow rate and to allow simple and inexpensive measurement by providing a TC reaction section, IC reaction section, carbon dioxide detecting section, automatic sample injecting mechanism, and a flow rate judging section. CONSTITUTION:High-purity air is so controlled by a flow rate control valve and a flow meter in such a manner that said air is transferred at a prescribed flow rate to an analyzing flow path (a) from a carrier gas supply section 2. Conditioning is executed by setting the temp. in a heating furnace 32 at 680 deg.C. A syringe pump driving section 84 is driven to fill the inside of a sample supplying pipe (e) for TC with a sample liquid in the automatic sample injecting mechanism 8 and thereafter, the prescribed volume of the sample is injected to the TC reaction section 3 by which the carbon dioxide derived from the total carbon in the sample is measured by the carbon dioxide detecting section 7 and the TC value is stored. The same volume of the sample is injected to the IC reaction section 4, by which the carbon dioxide derived from the inorg. carbon in the sample is measured in the detecting part 7 and is stored as the IC value. The TOC value of the sample is calculated from the stored values of the TV value and IC value and is displayed on a display section 94.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field This invention relates to an organic carbon measuring device. More specifically, the present invention relates to an organic carbon measuring device that measures total organic carbon contained in industrial wastewater, lake water, seawater, river water, and the like.

(b) Conventional technology Conventionally, an organic carbon measuring device for measuring total organic carbon in water has been equipped with a carrier gas supply section, a sample injection port, a high-temperature heating furnace, and a total carbon combustion catalyst. T.C.
) An analysis flow path that connects an inorganic carbon (IC) reaction tube equipped with a combustion tube, a sample injection port, and a low-temperature heating furnace and equipped with an inorganic carbon reaction catalyst, and a non-dispersive infrared gas detector that detects carbon dioxide. Combustion-infrared organic carbon measuring devices constructed in this way are widely used. This device is usually equipped with an automatic sample injection mechanism that can measure and inject a predetermined amount of sample into the TC combustion section or IC reaction section. The automatic sample injection mechanism includes a sample collection channel (
A), a TC sample supply channel (B) connected to the sample injection port of the TC combustion section, a TC sample supply channel (C) connected to the sample injection port of the IC reaction section, and the sample supply channel (C) connected to the sample injection port of the IC reaction section. Collection channel (
It mainly consists of a switching valve that can switch and connect A) to either the supply channel (B) or (C), and a syringe pump connected to the switching valve.

(c) Problems to be Solved by the Invention In the organic carbon measuring device as described above, if a change in the flow rate of the carrier gas occurs, a measurement error will occur.

The following causes can be considered for the change in the flow rate of the carrier gas, especially the decrease in the flow rate.

In other words, 1) Increased ventilation resistance due to the accumulation of salt contained in the sample in the catalyst part in the TC combustion tube, 2) Gas leakage from cracks etc. caused by deterioration of the TC combustion tube, 3) Flow path These include gas leakage from component parts, 4) clogging of filters, and 5) gas shortage in the cylinder gas of the carrier gas supply source.

The present invention has been made in view of the above situation, and it is an object of the present invention to provide an organic carbon measuring device that can easily check changes in carrier gas flow rate.

(d) Means for Solving the Problems Thus, according to the present invention, an analysis channel connects 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. and an automatic sample injection mechanism that can measure and collect a predetermined amount of sample and inject it into the TC reaction section or the IC reaction section, and the automatic sample injection mechanism is configured to be able to inhale and collect a predetermined amount of air. At the same time, based on the time required for the intake air supplied to the analysis channel via the TC reaction section or the IC reaction section by this automatic sample injection mechanism to be detected by the carbon dioxide detection section, the above-mentioned An organic carbon measuring device is provided that includes a flow rate determination section that can determine whether the flow rate of a carrier gas in an analysis channel is appropriate.

The present invention is characterized by an organic carbon measuring device configured to be able to easily monitor carrier gas flow rate at any time without using a standard sample.

In the apparatus of this invention, the automatic sample injection mechanism is configured to be able to inhale and sample a predetermined amount of air. The configuration may be any configuration as long as it can supply a certain amount of air to the carrier gas transfer channel, for example, a sample collection channel connected to the sample storage section, an IC connected to the sample injection port of the TC reaction section, etc. The sample supply channel, the IC sample supply channel and the air suction channel connected to the sample injection port of the IC reaction section are respectively connected, and the sample collection channel is connected to the IC sample supply channel or the IC sample supply channel. and a syringe pump connected to the switching valve. Examples include, but are not limited to, Shino consisting of.

In the flow rate determining section of the apparatus of the present invention, air supplied to the analysis channel by the automatic sample injection mechanism configured as described above is transported through the analysis channel by a carrier gas, and is detected by a carbon dioxide detection section set downstream. The apparatus is configured to determine whether or not the carrier gas flow rate is appropriate based on the time required for the carrier gas to flow. That is, a timing means for measuring the above-mentioned required time (1), a storage means for storing in advance the required time at an appropriate carrier gas flow rate as a reference, and this stored standard required time (T) and the above-mentioned required time. (1), and a display means for displaying the results of the comparison means are suitable. The determination in the flow rate determining section may be made using either the IC sample supply channel or the IC sample supply channel of the automatic sample injection mechanism. Furthermore, it is preferable to start measuring the required time when the intake air is supplied to the TC reaction section or the IC reaction section, but the timing is not limited thereto. The air was
The timing may be started when the sample is transferred to the IC sample supply channel or the IC sample supply channel; in other words, the same conditions (flow channel, timing Any device that measures time at a starting point, etc.) is fine. The above-mentioned judgment unit basically judges the suitability of the carrier gas flow rate as "fail" when the carrier gas flow rate is T, and as "suitable" in other cases. Therefore, if necessary, Tit
In this case, the answer may be "no".

Further, in the apparatus of the present invention, the flow rate determining section may be configured to issue an alarm etc., for example, in the case of the above-mentioned "no". Furthermore, the flow rate may be configured to be automatically adjusted to a predetermined appropriate flow rate based on the output signal of the flow rate determination section. In this case, it is preferable to adopt a configuration in which the carrier gas flow rate of the carrier gas supply section is adjusted by a motor-controlled flow controller (which may also be a pressure controller). Furthermore, it may be configured such that the full scale of the measurement range of the carbon dioxide detector can be adjusted between normal TOC measurement and when checking the carrier gas flow rate.

Note that the TO reaction section, IC reaction section, and carbon dioxide detection section of the device of the present invention may have the same configuration as that provided in a conventional TOC fractionator, and the Similar catalysts can be used.

(e) Effect According to the present invention, a predetermined amount of air is sucked and sampled through the air suction pipe by the automatic sample injection mechanism, and the TC sample is collected through either the TC sample supply channel or the IC sample supply channel.
When supplied to either the reaction section or the IC reaction section, the supplied air is transferred to a carrier gas that passes through the TC reaction section and the IC reaction section in this order, and is then transported to the downstream carbon dioxide detection section. The carbon dioxide component contained in the water is detected. The appropriateness of the flow rate of the carrier gas must be determined based on the time required for this detection.

The present invention will be described in detail below with reference to Examples, but the present invention is not limited thereby.

(F) Embodiment FIG. 1 is an explanatory diagram of the configuration of an embodiment of the organic carbon measuring device of the present invention. In this figure, organic carbon measuring device (1)
consists of a carrier gas supply section (2), a total carbon (TC) reaction section (3), an inorganic carbon (IC) reaction section (4), a gas-liquid separator (
5), an analysis channel (a) connecting a filter (6) and a carbon dioxide detection section (7) in this order, an automatic sample injection mechanism (8), and a control section (9).

The carrier gas supply section (2) includes an air cylinder (not shown),
It has a flow control valve and a flow meter.

The TC reaction section (3) consists of a quartz TC combustion tube (inner diameter 14+nm, outer diameter 16 nm) equipped with a sample injection port (33) at the top.
mm, length 25C1 nm) (31), and the combustion tube (3
1). The combustion tube X31) is filled with a platinum catalyst as an oxidation catalyst (34).

The IC reaction section (4) includes an IC reaction tube (41) provided with a sample injection port (42) at the top, and a drain channel (b) connected to the reaction tube (41). has been done.

The reaction tube (41) is filled with a strongly acidic cation exchange resin as an IC reaction catalyst.

The carbon dioxide detection unit (7) includes a detector that detects changes in the concentration of carbon dioxide contained in the carrier gas as changes in the capacitance of a microphone capacitor, a sample cell (in this case, capacity 30 m12), a comparison cell, and a non-contact unit that includes a light source. It consists of a distributed infrared analyzer (o+tR) (71). In addition, the above minute meter has a CO and gas concentration of 20pp.
The measurement range can be adjusted from m to 200 pPm.

The automatic sample injection mechanism (8) includes an air intake pipe (c), a sample collection pipe (d) connected to the sample storage tank (81), and a T
TC connected to sample injection port (33) of C reaction section (3)
A flow path switching valve (8) equipped with an IC sample supply line (e), an IC sample supply line (f) connected to the sample injection port (42) of the IC reaction section (4), and a syringe pump (82).
3). The syringe pump (82) is configured so that a fixed amount of air or sample can be metered out by means of a syringe pump drive (84). A motor-driven four-way switching valve is used as the flow path switching valve (83). The valve switching of the flow path switching valve (83) and the syringe pump driving section (84) are driven by a sequence preset in the control section (9), which will be described later.

The control unit (9) includes an MPU (91), a storage unit (92), a comparison/calculation unit (93), a display unit (94), and a timer (9).
5), a carbon dioxide detection section (7), a flow path switching valve (83), and a ring pump drive section (84).
) is electrically connected to the This control unit (9) recognizes the drive control of the automatic sample injection mechanism (8) and the carbon dioxide detection signal obtained by the carbon dioxide detection unit (7) through the amplifier (1O), and calculates the carbon dioxide concentration. The main functions are calculation processing and flow rate judgment to determine the appropriateness of the carrier gas flow rate in the minute Fr flow path (a).

Hereinafter, the operation of the organic carbon measuring device (1) of the present invention based on the control section (9) will be explained.

(i) When measuring TOC, first, carrier gas supply section (2) - TC reaction section (3) - IC reaction section (4) - gas-liquid separator (5) - filter (6) - carbon dioxide detection section (7) in this order to the analysis channel (a), the flow rate is set such that high-purity air is transferred from the carrier gas supply section (2) to the analysis channel at a predetermined flow rate (for example, about 150 m12/m1n). The heating furnace (3
2) Set the internal temperature to 680°C and perform conditioning.

After that, in the automatic sample injection mechanism (8), the flow path switching valve (83) is switched so that the sample collection conduit (d) and the IC sample supply conduit (e) are communicated with each other, and the cylinder bomb drive unit (84 ) to drive the IC sample supply conduit (e
) with the sample solution, then add a predetermined amount (e.g. 300μg
) is injected into the TC reaction section (3), carbon dioxide derived from the total carbon contained in this sample is measured in the carbon dioxide detection section (7), and the result is calculated and calculated to obtain the TC value. be remembered.

Next, the flow path switching valve (83) is connected to the sample collection pipe (d).
) and the IC sample supply conduit (f), and then inject the same amount of the same sample into the IC reaction section (4) in the same manner as above, to remove the contents contained in this sample. The carbon dioxide derived from the inorganic carbon that is
7), and the results are processed and stored as IC values.

By subtracting from the stored values of these TC values and IC values, the TOC value of the sample is calculated and displayed on the display (
94).

(ii) When determining the carrier gas flow rate, set the measurement range of the carbon dioxide detector (7) to a predetermined value (for example, 20 ppm, COt full scale) when the carrier gas flow rate in the analysis channel (a) is appropriate. After switching to the range, the air suction pipe (c) of the automatic sample injection mechanism (8) and, for example, the IC sample supply pipe (e) are communicated with each other by the flow path switching valve (83), and the ring bomb drive unit ( 84) to suck and collect a certain amount (300 μQ) of air, and supply it to the IC sample supply conduit (e). At this time, a timer (95) is activated. The above intake air is I
The sample is supplied to the analysis channel (a) via the C sample supply pipe (e), and the carbon dioxide concentration in the intake air is detected by the carbon dioxide detection section (7). The time counted by the timer (95) until this signal is detected is stored in the storage section (92) as a standard time (T). In the above case, the concentration of carbon dioxide normally contained in the air is approximately 350p.
p.m.

The sample cell capacity of the force detection section (7) is approximately 30n.
+Q, so the carbon dioxide concentration detected for 300 μQ of intake air is 350 (ppm,) Xe = 3.5 (ppm, ), and when the range of the detection part (7) is set to 20 ppm, full scale. , a concentration that is sufficiently detectable.

Next, when checking the carrier gas flow rate during TOC measurement, after switching the measurement range in the same manner as above, inject a predetermined amount of air from the automatic sample injection mechanism through the IC sample supply pipe (e). and the time (1) until detection in the carbon dioxide detection section (7) is measured.

Next, the obtained time (1) is compared with the memorized standard time (T), and in the case of Tit, a display indicating that the carrier gas flow rate is smaller than the predetermined flow rate is displayed on the display section (94). In addition,
It may be configured to issue an alarm instead of or together with the above display.

Furthermore, the carrier gas flow rate may be automatically adjusted to an appropriate flow rate based on the comparison signal such that T<t. In this case, the carrier gas supply section (
2) The carrier gas flow rate may be adjusted using a motor-controlled flow controller (or pressure controller), and the motor may be driven and adjusted using the comparison signal.

In addition, the above standard time (T) is the sample supply pipe for IC (r).
In this case, the check on the carrier gas flow is performed using this pipe (f).
) is used.

(g) Effect of the invention According to this invention, due to inappropriate carrier gas flow rate,
Measurement errors can be prevented from occurring. Since air is used to check the flow rate, it can be easily done without using standard water or the like. Almost no special mechanism is required for the check, and it can be implemented at low cost.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the organic carbon measuring device of the present invention. (2)...Carrier gas supply section, (3)...
・Total carbon (TC) reaction part, (4)... Inorganic carbon (
IC) reaction section, (5)... gas-liquid separator, (6
)...Filter, (7)...Carbon dioxide detection unit, (8)...Automatic sample injection mechanism, (9
)...Control unit, (TC)...Amplifier, (31)...TC combustion tube, (32)...
... Heating furnace, (41) ... IC reaction tube, (
91)...MPU. (92)...Storage section, (93)...
・Comparison/calculation section, (94)...display section,
(95)...Timer, (a)...Analysis channel, (c)...Air suction pipe, (d)...
... Sample collection pipe,

Claims (1)

[Claims] 1. An analysis flow path that connects 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, and a predetermined amount of sample to be measured and collected.
It is equipped with an automatic sample injection mechanism that can inject into the C reaction section or the IC reaction section, and the automatic sample injection mechanism is configured to be able to inhale and collect a predetermined amount of air, and the automatic sample injection mechanism can inject into the TC reaction section. Or, determine whether the carrier gas flow rate in the analysis channel is appropriate based on the time required for the intake air supplied to the analysis channel via the IC reaction section to be detected by the carbon dioxide detection section. An organic carbon measuring device comprising a flow rate determination unit that can perform