JP2855830B2 - Moisture and total organic carbon analyzer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus suitable for analyzing water and total organic carbon contained in a gas.

(Prior art) To analyze organic and inorganic carbon dissolved in water, use a device that connects a non-dispersive infrared gas analyzer to a combustion tube that selectively burns all carbon and inorganic carbon. It has been practiced to convert carbon contained in water into carbon dioxide gas, which is detected by a non-dispersive infrared gas analyzer.

(Problems to be Solved by the Invention) However, since such a device targets carbon contained in water for analysis, for example, organic carbon and water contained in air or the like in a plant cultivation environment. Cannot be applied to the analysis.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a novel analyzer capable of simultaneously analyzing moisture and organic carbon contained in a gas such as air. It is in.

(Means for Solving the Problems) In order to solve such a problem, in the present invention,
A calcium carbide pipe connected via a sample inlet to an auxiliary combustion gas source from which carbon dioxide and water have been removed, an all-carbon combustion pipe connected via a sample inlet to the discharge side of the calcium carbide pipe, and an all-carbon combustion pipe A carbon dioxide gas detecting means connected to the discharge side of the tube, and an inflow side through the sample inlet to the auxiliary gas source,
Further, the discharge side is provided with an inorganic carbon combustion pipe connected to the carbon dioxide gas detecting means.

(Action) After the water contained in the gas is converted into acetylene by calcium carbide, it is converted into carbon dioxide by the combustion tube together with the total carbon contained in the sample, and the concentration is detected by the carbon dioxide detection means. . Further, all the carbon contained in the gas is converted into carbon dioxide by the all carbon combustion tube, and the concentration is measured by the carbon dioxide detection means. By obtaining these differences, the concentration of water contained in the gas can be known. The inorganic carbon is converted into carbon dioxide by an inorganic carbon combustion tube, and its concentration is detected by carbon dioxide detection means. The organic carbon can be known by calculating the difference between the total carbon concentration and the inorganic carbon concentration.

(Embodiment) Therefore, the details of the present invention will be described below based on an illustrated embodiment.

FIG. 1 shows an embodiment of the present invention. In the drawing, reference numeral 1 denotes a switching valve connected to an auxiliary air source 2 from which moisture and carbon dioxide gas have been removed. A calcium carbide pipe 5 containing calcium carbide 4 is connected via a sample injection port 3 for use. At the outlet of the calcium carbonate tube 5, an oxidation catalyst 7 is accommodated via a sample inlet 6 for total organic carbon measurement, and an all-carbon combustion tube 9 maintained at a high temperature of about 680 ° C. by a heater 8 is connected. ing.
A non-dispersive infrared gas detector 12 is connected to the outlet of the all-carbon combustion tube 9 through a moisture removal unit 10 and a filter unit 11.
Is connected.

The other outlet of the switching valve 1 accommodates an oxidation catalyst 14 via an inorganic carbon sample inlet 13 and a relatively low temperature of about 150 ° C., which is relatively low enough to oxidize only inorganic carbon by the heater 15. The combustion tube 16 is connected, and its outlet is connected to the moisture removal unit 10.

In this embodiment, when the switching valve 1 is set to the first flow path and the sample is injected from the sample inlet 3 for moisture measurement, the sample flows into the calcium carbonate tube 5 together with the dry air from the air source 2 for combustion support. Then, it is converted into acetylene by a reaction of 2H ₂ O + C ₂ Ca → C ₂ H ₂ . Acetylene flows into the all-carbon combustion tube 9 via the total-carbon-measuring sample inlet 6, and is decomposed into carbon dioxide and water by a reaction of C ₂ H ₂ + O ₂ → CO ₂ + H ₂ O, and is included in the sample. total carbon being are converted into ^{_{C p H q n r + n}} O 2 = p CO 2 + q / 2 H 2 O + r NO made both carbon dioxide and water by the reaction.

The carbon dioxide gas and the moisture are removed by the moisture removing unit 10 and the concentration of the carbon dioxide gas is measured by the non-dispersive infrared gas detector 12 via the filter unit 11. Needless to say, the measurement value D _t at this stage will indicate the sum of the concentration T _tc the concentration D _h and the total carbon in the water in the sample.

Next, when the same sample is injected from the sample injection port 6 for total carbon measurement, the same sample is carried to the all carbon combustion tube 9 by the auxiliary combustion air flowing through the calcium carbide tube 5, and the organic matter contained in the sample is removed. All of the carbon and inorganic carbon are oxidized and decomposed into carbon dioxide and moisture. After the water is removed from the carbon dioxide gas and the water by the water removing unit 10, the concentration _Dtc of the total carbon is measured by the non-dispersive infrared gas detector 12.

Thus it is possible to know the concentration of water contained in the sample by calculating the difference D _t -D _tc concentration D _tc obtained by concentration D _t and the current measurement obtained by previous measurement.

Next, when the switching valve 1 is switched to the other flow path and the same sample as the previous sample is injected into the sample injection port 13 for inorganic carbon measurement,
After being transported to the inorganic carbon combustion tube 16 by the combustion support air, only the inorganic carbon contained in the sample is selectively oxidized and decomposed into carbon dioxide gas and moisture, and after the moisture is removed by the moisture removing unit 10, the non- The concentration T _IC of the inorganic carbon is measured by the dispersion type infrared gas detector 12.

Therefore, the concentration D _oc of the organic carbon can be obtained by calculating the difference D _tc −D _IC between the concentration D _{tc of the} total carbon and the concentration D _{IC of the} inorganic carbon.

[Example] After calibrating the same apparatus as above using a mixture of synthetic air to which 800 PPM of carbon dioxide and 200 PPM of moisture were added as a standard sample, the water and organic carbon contained in the air in the ripening room of tomatoes were measured. The results agreed with the measurement results by the device with high accuracy. In addition, since the total organic carbon present in the plant ripening room is ethylene generated during the ripening process of the plant, the concentration of ethylene is measured by gas chromatography, and the measurement result is compared with the measurement result of the organic carbon concentration by the same equipment. As a result, they agreed with extremely high precision.

When it is desired to analyze the hydrogen contained in the sample, as shown in FIG. 2, between the switching valve 1 and the sample inlet 3 for moisture measurement, the sample for hydrogen measurement is injected from the switching valve 1 side. Entrance 20
Is provided with a moisture removing unit 21 and an oxidation furnace 22 for selectively oxidizing only hydrogen.
, The hydrogen is selectively oxidized by the oxidation furnace 22 to be converted to water. This water is converted to acetylene by the calcium carbide tube 5, and is detected as carbon dioxide by the above-described steps.

In this embodiment, the carbon dioxide gas is detected by the non-dispersive infrared gas detector. However, the same operation can be achieved by using another type of carbon dioxide detector such as a thermal conductivity type gas detector. Obviously,

(Effects of the Invention) As described above, in the present invention, a calcium carbide pipe connected to an auxiliary combustion gas source from which carbon dioxide gas and moisture have been removed via a sample injection port, and a sample injection port on the discharge side of the calcium carbide pipe. And a carbon dioxide detecting means connected to the discharge side of the full carbon combustion pipe, an inorganic gas connecting the inflow side to the auxiliary combustion gas source via the sample inlet, and a discharge side connected to the carbon dioxide gas detecting means. Since it is equipped with a carbon combustion tube, after converting the moisture contained in the gas to acetylene, it can be converted to carbon dioxide by the carbon combustion tube, and measured by the same method as total carbon and inorganic carbon. It is possible to simultaneously analyze water and total organic carbon contained in the sample with high sensitivity.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus showing one embodiment of the present invention, and FIG. 2 is a block diagram showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Switching valve 2 ... Combustion gas source 3 ... Sample inlet for moisture measurement 5 ... Calcium carbide tube 6 ... Sample inlet for total carbon measurement 9 ... Total carbon combustion tube 10 ... Water removal unit , 11 ... Filter 12 ... Non-dispersive infrared gas detector 13 ... Sample inlet for inorganic carbon measurement 16 ... Inorganic carbon combustion tube

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G01N 21/00-21/01, 21/17-21/6 1 G01N 31/00

Claims (1)

(57) [Claims] 1. A calcium carbide pipe connected to an auxiliary combustion gas source from which carbon dioxide and moisture have been removed via a sample inlet, and an all-carbon combustion pipe connected via a sample inlet to a discharge side of the calcium carbide pipe. A carbon dioxide detection means connected to the discharge side of the all carbon combustion pipe, an inorganic carbon combustion pipe connected to the auxiliary gas source on the inflow side via a sample inlet, and connected to the carbon dioxide detection means on the discharge side. Moisture and total organic carbon analyzer.