JP2002031628A - Elemental analyzer - Google Patents

Abstract

(57) [Problem] To provide an elemental analyzer which is not affected by pressure fluctuation due to water vapor generated in a combustion tube. A gas flow control unit (12) for controlling a high-purity air at a constant flow rate and supplying it as a carrier gas, a humidifier (13) for providing humidity to the carrier gas, and a flow of a measurement gas from a TC combustion pipe (5). A non-return valve 11 is connected to supply the carrier gas to the TC combustion pipe 5, and a bypass flow path 18 is provided upstream of the check valve 11 so as to bypass the carrier gas to the IC reactor outlet side. Thereby, the humidifier 11 due to the generation of water vapor in the TC combustion pipe 5
Pressure rise in the inside is suppressed, and influence on measurement accuracy can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid sample such as waste water, sewage and environmental water or a solid sample such as soil and fiber,
Further, the present invention relates to an element analyzer used for measuring the amount of elements contained in a gas sample in an environmental atmosphere, and inspecting and managing the sample substance.

[0002]

2. Description of the Related Art The configuration of a total organic carbon meter (TOC meter) is shown in FIG. 2 as an example of a conventional elemental analyzer, and a method of measuring the total organic carbon amount will be described. After the sample 3 in the sample container 2 is sucked into the syringe type sample injector 1 connected to the common port of the rotary valve 4, the sample injector 1 is switched to the port on the slide TC sample injector 5b side. A fixed amount of the sample is injected into the TC combustion tube 5. Carbon component in the sample 3 is burned oxidized at high temperature under the carrier gas 14 supplied from the TC catalyst and high purity air cylinder 6a of the TC combustion tube 5, it is all converted to CO _2. The combustion gas containing CO ₂ , that is, the measurement gas passes through an IC reactor 7 and a dehumidification / gas processing unit 8 and is used for an infrared gas analysis unit (NDI).
R) 9 where the CO ₂ concentration is measured. The data processing unit 10 calculates the total carbon amount in the sample based on the value of the CO ₂ concentration.

Next, the sample injector 1 is switched to the port on the sample container 2 side, and after the sample 3 is sucked into the sample injector 1, the sample injector 1 is switched to the port on the slide IC sample injector 7 b, and a predetermined amount is set. Is injected into the IC reactor 7. I
In the C reactor 7, the inorganic carbon (IC) in the sample 3 reacts with the IC reaction solution 7a stored therein to form CO ₂ . Then, as in the case of the TC amount measurement described above, this CO
₂ was measured by NDIR9, and the data processing unit 1
The IC amount is calculated from 0. From the TC and IC amount thus measured, the total organic carbon amount TOC is calculated as TOC
= TC-IC.

[0004]

The conventional TOC meter is configured as described above. However, when the sample 3 is injected into the TC combustion tube 5, the sample 3 burns under the TC catalyst and the carrier gas and the steam Other gas components are generated and the internal pressure increases. When the internal pressure of the TC combustion pipe 5 increases, the check valve 1
1 is closed, the carrier gas 14 from the gas flow controller 12 is pressurized in the humidifier
Internal pressure increases.

The measurement gas in the TC combustion tube 5 is supplied to the IC reactor 7
When the pressure is reduced and sent to the infrared gas analyzer 9 via the, the check valve 11 opens and the carrier gas 14
The carrier gas 14 flows into the humidifier 13 for a while.
Flows, the flow rate of the carrier gas in the TC combustion pipe 5 increases from a predetermined flow rate, and the measured gas concentration changes. In this state, when the measurement gas enters the detector of the infrared gas analyzer 9, CO
_An error occurs in the measurement results of the _two concentrations.

The present invention has been made in view of such circumstances, and has been made in consideration of the measurement error of elements caused by an increase in internal pressure due to generation of water vapor and other gas components in a sample combustion tube or a sample reaction tube. It is an object of the present invention to provide an elemental analyzer from which is eliminated.

[0007]

In order to achieve the above object, an elemental analyzer according to the present invention is characterized in that a sample is injected into a sample combustion tube or a sample reaction tube and reacted, and the obtained measurement gas is analyzed by the analysis means. In an elemental analyzer that analyzes and measures the amount of elements in a sample, a gas flow controller for supplying a constant flow rate of a carrier gas to the sample combustion tube, a humidifier for providing humidity to the carrier gas, A check valve for preventing backflow of gas is connected to supply a carrier gas to the sample combustion tube, and a bypass for bypassing a part of the carrier gas from the sample combustion tube upstream of the check valve. A flow path is provided.

[0008] The element analyzer of the present invention has the above structure,
Eliminates measurement errors caused by detectors in elemental analyzers by reducing the pressure increase in the humidifier due to the increase in internal pressure due to water vapor generated in the TC combustor by increasing the flow rate of carrier gas in the bypass flow path. can do.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A total organic carbon analyzer (TOC analyzer) according to one embodiment of the present invention will be described with reference to the drawings. The basic configuration of the TOC meter according to the present embodiment is the conventional TC shown in FIG.
Although the same as the OC meter, the configuration of the oxidation reaction section from the time when the sample 3 is collected until the oxidation reaction is performed is as shown in FIG.

The oxidation reaction section according to the present invention comprises a sample injector 1 and a rotary valve 4 for sucking the sample 3 in the sample container 2 and injecting it into the slide TC sample injection section 5b or the slide IC sample injection section 7b. And the sliding TC
The sample 3 injected via the sample injection section 5b is burned and oxidized with high heat from the TC furnace 5a under the carrier gas supplied from the carrier gas supply section 20 and the oxidation catalyst, which is a feature of the present invention, TC combustion tube 5 that converts all carbon to CO ₂
And the sample 3 injected through the slide type IC sample injection portion 7b is transferred to the inorganic carbon (IC) under the IC reaction solution 7a.
From an IC reactor 7 for converting CO ₂ into CO ₂ .

As shown in FIG. 1, the carrier gas supply section 20 converts the high purity air 6 supplied from the high purity air cylinder 6a which stores the compressed high purity air 6 into a carrier gas 14 having a constant flow rate. Gas flow controller 12 to be controlled
And a humidifier 13 for providing humidity to the carrier gas 14 for the purpose of reducing the blank value, and a fixed flow rate of the carrier gas sent from the humidifier 13 through a check valve 11 for a slide TC sample. A carrier gas channel 17 having a capillary 15 as a channel for supplying to the injection section 5b;
A bypass flow path 18 having a capillary 16 as a flow path for diverting another constant flow rate to the outlet of the IC reactor 7.

The above-mentioned capillary 15 and capillary 1
For 6, a stainless steel thin tube having an inner diameter of about 0.1 mm is used, and the flow rate of the carrier gas passing through each flow path is adjusted by adjusting its length. For example,
In this embodiment, the carrier gas flow path 17 and the bypass flow path 18
The carrier gas flow rates of 150 ml / min and 7
It is adjusted to 5 ml / min (2: 1 in flow ratio).

The oxidation reaction of the element analyzer having the above structure is performed according to the following operation procedure. First, the sample injector 1 is switched to the sample container 2 side port by the rotary valve 4, and the sample 3 is sucked into the sample injector 1. Next, the sample injector 1 is switched to the port on the slide TC sample injector 5b side, and the sample 3 is injected from the sample injector 1 into the TC combustion tube 5 via the slide TC sample injector 5b.

The TC combustion tube 5 has a built-in TC catalyst and is supplied with a carrier gas of 150 ml / min from the carrier gas passage 17 via the check valve 11. Heated.
When the sample 3 is injected into the TC combustion tube 5, all the carbon in the sample 3 is burned and oxidized and converted into CO ₂ , and
During the combustion, steam and other gas components are generated, and the internal pressure of the TC combustion tube 5 increases. As a result, the check valve 11 is closed and the pressure in the humidifier 13 tends to increase, but the flow rate of the carrier gas in the bypass passage 18 also increases in proportion to the increase in the pressure. Can be suppressed.

When the internal pressure of the TC combustion tube 5 returns to the original pressure by burning the sample 3 of the TC combustion tube 5 to become a measurement gas and sending it to the IC reactor 7, the check valve 11 opens, The carrier gas flow rate in the carrier gas flow path 17 and the carrier gas flow rate in the bypass flow path 18 are respectively restored to the original flow rate ratios. As a result, the TC combustion tube 5 has 150 ml
/ Predetermined flow rate carrier gas of min is supplied, the measuring gas containing CO ₂ of a constant concentration flows into detecting section of the same infrared gas analyzer unit 9 to that shown in FIG. 2, the entire carbon CO ₂ And the data processor 10 calculates the total carbon amount (TC) in the sample.

Next, as shown in FIG. 2, the sample injector 1 is switched to the port on the sample container 2 side by the rotary valve 4, and the sample 3 is sucked into the sample injector 1, and then the sample injector 1 is slid. Switching to the IC sample injection section 7b side, a predetermined amount of the sample 3 is injected into the IC reactor 7 by the sample injector 1. Sample 3 in inorganic carbon (IC) is converted to CO _2, the concentration of the CO ₂ is measured by NDIR9, IC amount by the data processing unit 10 is calculated. From the TC and IC amounts thus measured, the total organic carbon amount TO
C is calculated as TOC = TC-IC.

The ratio of the flow rate of the carrier gas in the bypass passage 18 to the flow rate of the carrier gas in the carrier gas flow path 17 is within 0.5 to 1 and is as small as possible within the allowable range of the measurement error. It is desirable.

As described above, in this embodiment, a liquid sample is described as a measurement target, but a solid sample or a gas sample can be used as a measurement target. If it is a solid sample, load the sample on a belt conveyor,
The amount of elements is measured by the same measurement method as in the case of a liquid sample by sending it to the TC combustion tube 5 installed in a horizontal state and burning and oxidizing it, or by directly introducing the gas sample into the TC combustion tube 5. be able to. When measuring the total nitrogen (TN) in the sample, the total nitrogen is converted to nitric oxide (NO) by combustion oxidation, and a chemiluminescent gas analyzer is used instead of the infrared analyzer 9. NO
By measuring the total amount of nitrogen, the total amount of nitrogen can be measured.

[0019]

The elemental analyzer of the present invention is configured as described above, and can suppress the pressure fluctuation due to the water vapor generated in the combustion tube. Since the pressure is constant, measurement accuracy and stability can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of an oxidation reaction section of an element analyzer of the present invention.

FIG. 2 is a schematic configuration diagram of a conventional element analyzer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Sample injector 2 ... Sample container 3 ... Sample 4 ... Rotary valve 5 ... TC combustion tube 5a ... TC furnace 5b ... Slide type TC sample injection part 6 ... High purity air 6a ... High purity air cylinder 7 ... IC reactor 7a ... IC reaction liquid 7b ... Slide type IC sample injection part 8 ... Dehumidification / gas processing part 9 ... Infrared gas analysis part (NDIR) 10 ... Data processing part 11 ... Check valve 12 ... Gas flow control part 13 ... Humidifier 14 ... Carrier gas 15, 16 Capillary 17 Carrier gas channel 18 Bypass channel

Claims (1)

[Claims] 1. A sample is injected into a sample combustion tube or a sample reaction tube to cause a reaction, and the obtained measurement gas is analyzed by an analysis means.
In an elemental analyzer for measuring the amount of elements in a sample, a gas flow control unit for supplying a constant flow rate of a carrier gas to the sample combustion tube, a humidifier for giving humidity to the carrier gas, and a reverse flow of the measurement gas And supplying a carrier gas to the sample combustion tube by connecting a check valve that prevents the carrier gas from flowing through the sample combustion tube on the upstream side of the check valve. An elemental analyzer characterized by being provided.