CN203479599U - Sample preparation device for organic tritium measurement - Google Patents

Abstract

The utility model discloses a sample preparation device for organic tritium measurement, which comprises a sample combustion area, a catalytic area and a collection area. The collection area is a cold trap collection device. The sample combustion area is provided with oxygen and nitrogen inlets. A catalyst is provided in the catalytic zone, and it is characterized in that: the sample combustion zone and the catalytic zone are mainly composed of a horizontally placed dual-temperature zone tubular combustion furnace, and a second oxygen inlet is provided on one side of the catalytic zone, so that The cold trap collection device communicates with the end of the catalytic zone away from the sample combustion zone. The utility model can effectively control the combustion rate, solve the problems of deflagration and insufficient combustion, and improve the stability and reliability of measurement; the oxygen concentration in the catalytic zone is controllable, and the catalytic efficiency is improved.

Description

A sample preparation device for organic tritium measurement

technical field

The utility model relates to an environment monitoring device, in particular to a sample preparation device for measuring the content of environmental biological organic tritium.

Background technique

Tritium is a radioactive isotope of water. Since the beta decay of tritium will only release high-speed moving electrons and will not penetrate human skin, only inhalation of large amounts of tritium will be harmful to the human body. However, tritium in tritium water can combine with animal and plant organic molecules to form organically bound tritium (OBT). It will be fully absorbed in 40-45 minutes. The organically bound tritium entering the human body will cause direct internal exposure, thereby seriously endangering the health of the human body. Studies have shown that the toxicity of tritium water is 520 times that of the nuclide tritium.

Units engaged in research and production of tritium will discharge a small amount of tritium into the environment, causing pollution to the environment. In order to analyze the degree of tritium contamination of environmental biological samples, the current common method is to convert organic tritium into tritiated water by oxidative combustion method, collect it through cold traps, and measure the content of tritium in it with a liquid scintillation counter. For example, in the article "Development of Full Tritium Combustion Sample Preparation Device" in Issue 01, 2008 of "China Nuclear Science and Technology Report", a full tritium combustion sample preparation device is disclosed, which consists of a heating chamber, a catalytic chamber, a condenser tube, and a cold trap to collect The device consists of a heating chamber located below the catalytic chamber with oxygen and nitrogen inlets. The sample is burned in the heating chamber, and the incompletely burned part is catalyzed and oxidized by the catalytic chamber to form tritium water, which is collected by the cold trap for liquid scintillation counter detection.

This device can realize the sample preparation and measurement of organic tritium. However, in the structure of this device, due to the full combustion of the sample in the heating chamber through oxygen and nitrogen, the nitrogen content in the gas entering the catalytic chamber is relatively high, which is not conducive to catalysis. Oxidation is carried out, at the same time, the heating chamber is located below the catalytic chamber, and the temperature of the catalytic chamber is affected by the heating chamber, which is difficult to control. However, in environmental biological samples, the content of tritium is usually low, so the measurement resolution has a great influence on the measurement results.

Therefore, it is necessary to develop an organic tritium measuring device with improved structure to facilitate the measurement of environmental samples.

Contents of the invention

The purpose of the invention of the utility model is to provide a sample preparation device for organic tritium measurement, so as to measure the content of organic tritium in environmental biological samples with high sensitivity.

In order to achieve the purpose of the above invention, the technical solution adopted by the utility model is: a sample preparation device for organic tritium measurement, including a sample combustion area, a catalytic area and a collection area, the collection area is a cold trap collection device, and the catalytic area A catalyst is set in the center, and the sample combustion area is provided with oxygen and nitrogen inlets. The sample combustion area and the catalytic area are mainly composed of a horizontally placed dual-temperature zone tubular combustion furnace. On the side of the catalytic area, there is a The second oxygen inlet, the cold trap collection device communicates with the end of the catalytic zone away from the sample combustion zone.

In the above technical solution, by setting the combustion furnace horizontally, the temperature of the sample combustion zone and the catalytic zone can be controlled separately, so that a suitable catalytic reaction temperature can be set according to the needs. At the same time, a second oxygen inlet is set in the catalytic zone, which is beneficial to supplement oxygen. Avoid the problem that the concentration of carrier gas (nitrogen) in the gas coming from the sample combustion area is too high to affect the catalytic reaction, and improve the efficiency of the catalytic reaction. The selection of the catalyst is the prior art, and copper oxide can generally be used as the catalyst.

When in use, the sample is first dried to a constant weight, and the free water in the sample is removed. Put the dried sample into the sample combustion area for oxidative combustion, and the generated water vapor is carried by the carrier gas (nitrogen), catalyzed by the catalytic area for further oxidation, collected by the cold trap, and the collected water sample is distilled and made into a liquid flash Count the samples for measurement.

In actual measurement, in order to improve the accuracy of measurement, an elemental analyzer can be used to measure the content of hydrogen in the sample during the oxidative combustion process of the sample, and the recovery rate of hydrogen can be calculated according to the amount of water collected, and determined by the properties of the isotope Tritium recovery.

In the above technical solution, the dual-temperature-zone tubular combustion furnace is provided with independent temperature controllers corresponding to the sample combustion zone and the catalytic zone, and a control system is electrically connected to the temperature controllers.

A sample boat for holding samples is provided in the sample combustion zone.

In a preferred technical solution, the second oxygen inlet is located at one end of the catalytic zone close to the sample combustion zone.

Due to the application of the above-mentioned technical solutions, the utility model has the following advantages compared with the prior art:

1. The temperature of the sample combustion area and the catalytic area of the utility model can be controlled separately, and the combustion rate can be effectively controlled with the oxygen and nitrogen inlet, which solves the problems of deflagration and insufficient combustion, and improves the stability and reliability of the measurement.

2. The utility model sets the second oxygen inlet in the catalytic area, which solves the problem that the catalytic efficiency is affected by the excessive concentration of the carrier gas. At the same time, because the oxygen concentration in the catalytic area is controllable, the nitrogen intake in the sample combustion area can be adjusted according to needs. There is no need to worry about the catalytic problem in the later stage, which is more conducive to the control of combustion.

Description of drawings

Fig. 1 is a schematic structural view of an embodiment of the utility model.

Figure 2 is a schematic diagram of a distillation apparatus.

Among them: 1. Sample combustion area; 2. Catalytic area; 3. Collection area; 4. Sample boat; 5. Temperature controller; 6. Oxygen and nitrogen inlet; 7. Second oxygen inlet; 8. Cold trap collection device.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described:

Embodiment 1: Referring to Fig. 1, a sample preparation device for organic tritium measurement includes a sample combustion zone 1, a catalytic zone 2 and a collection zone 3, and the sample combustion zone 1 and the catalytic zone 2 are mainly composed of a horizontally placed The dual-temperature-zone tube-type combustion furnace is composed of, corresponding to the sample combustion zone 1 and the catalytic zone 2, respectively provided with an independent temperature controller 5, and a control system is electrically connected to the temperature controller 5; in the sample combustion zone 1- On the side, oxygen and nitrogen inlets 6 are provided. According to the needs, two inlets can be arranged, and one inlet can also be arranged. Oxygen and nitrogen are previously mixed by the introduction pipe, and the sample combustion area 1 is provided with a sample boat 4 for containing samples. ; In the catalytic zone 2, near one end of the sample combustion zone 1, a second oxygen inlet 7 is provided; the collection zone is a cold trap collection device 8, which is far from the sample combustion in the catalytic zone 2 One end of the area is connected.

Specifically, the dual-temperature-zone tubular combustion furnace can include a quartz tube of 50 mm × 1100 mm, a quartz boat with samples is placed on the right side of the quartz tube, and a catalyst is placed on the left side, and the catalyst is copper oxide; The right end is provided with oxygen and nitrogen inlets, and an air guide tube is inserted at the left end of the quartz tube as a second oxygen inlet for introducing oxygen. Two sets of heaters and temperature controllers are arranged around the quartz tube to independently control the temperature of the sample combustion zone and the catalytic zone. A cold trap is connected to the left end of the quartz tube to collect the generated water vapor to obtain a water sample.

Further, referring to the accompanying drawing 2, after the collected water sample is taken out, it can be placed in a distillation bottle, after adding a few glass beads, it is distilled on an electric furnace, and the slip-out liquid is collected in a beaker as a sample to be tested. .

When preparing samples, fresh samples are dried to constant weight by drying or freeze-drying, the dried samples are pulverized, a small amount of samples are taken out to measure the hydrogen content, and about 40g of the same samples are taken into the oxidation combustion device, such as Figure 1, the connection device, the collection cold trap is placed in an ice-water bath at 5-10°C, slowly adjust the flow rate of the gas flow meter, and first adjust the flow rate of the mixed gas in the combustion zone to 200ml/min (oxygen: nitrogen = 50ml/min: 150ml/min ), and then adjust the oxygen flow in the catalytic zone to 100ml/min. After the flow is stable, maintain ventilation for 5 minutes to drive out the air in the quartz tube.

After the catalytic zone rises to 750°C at a relatively fast speed, the combustion zone rises to 350°C at a rate of 1°C/min, maintains the temperature for 30 minutes, then rises to 750°C at a rate of 4°C/min, and maintains it for 2 hours. Finally, stop heating and stop ventilation. Take out the cold trap and weigh the quality of the produced water.

Add sodium peroxide to the collected water sample to adjust the pH to neutral (6-8), then pour the produced water into a 50ml distillation bottle, add two glass beads, add a small amount of potassium permanganate until the solution turns purple, and set up Distillation device, device diagram is shown in accompanying drawing 2. Take 8ml of distillate in a 20ml counting bottle, add 12ml of scintillation fluid and mix well, put it in a dark place for 24 hours and then measure.

Claims (4)

1. the sample preparation device that organic tritium is measured, comprise sample combustion district, catalytic domain and collecting region, described collecting region is cold-trap gathering-device, described sample combustion district is provided with oxygen and nitrogen inlet, in described catalytic domain, be provided with catalyzer, it is characterized in that: described sample combustion district and catalytic domain mainly consist of two warm area tubular type combustion furnaces of a horizontal positioned, in described catalytic domain one side, be provided with the second oxygen intake, described cold-trap gathering-device is communicated with one end away from sample combustion district in catalytic domain.

2. the sample preparation device that organic tritium according to claim 1 is measured, is characterized in that: the described pair of warm area tubular type combustion furnace Shang，Yu sample combustion district and catalytic domain are corresponding, are respectively equipped with independently temperature controller, are electrically connected to and are provided with control system with described temperature controller.

3. the sample preparation device that organic tritium according to claim 1 is measured, is characterized in that: in described sample combustion district, be provided with for holding the example boat of sample.

4. the sample preparation device that organic tritium according to claim 1 is measured, is characterized in that: described the second oxygen intake is arranged in catalytic domain near the one end in sample combustion district.

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