System for detritiation of humid air

Abstract

The present invention discloses a system for detritium removal from high-humidity air, comprising: a detritium removal unit, which comprises a gas booster pump, a flow controller, an inner tube of a drying tube, a catalytic reactor, an adsorber and a dew point meter connected in sequence through pipelines; a water collection unit, which comprises a rotor flowmeter, an outer sleeve of a drying tube and a water collector connected in sequence to the outlet of the adsorber; wherein, after the tritium-containing air containing more water enters the detritium removal unit, it is discharged after passing through the gas booster pump, the flow controller, the inner tube of the drying tube, the catalytic reactor, the adsorber and the dew point meter in sequence, and the on-site air discharged from the adsorber outlet is collected after passing through the rotor flowmeter, the outer sleeve of the drying tube and the water collector in sequence. The present invention adopts tritium oxygen catalysis and gas-liquid separation technology to realize the on-site cleaning of tritium; it can timely remove the tritium component in the high-humidity air under the condition of high-humidity background air, and realize the effective protection of the tritium-related environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of radioactive "three wastes" treatment, and specifically relates to a system for detritium removal from high-humidity air. The system can be applied to high-humidity air detritium removal occasions, timely remove tritium components in high-humidity air, and achieve effective protection of tritium-related environments. Background Art

[0002] Tritium is the only radioactive isotope of hydrogen. The maximum energy of the beta ray emitted by tritium decay is 18.6keV, and its average energy is 5.65keV. Tritium may corrode the containing material or cause degradation of material performance (fracture, aging). Moreover, tritium can enter the human body through inhalation, ingestion, and penetration through intact skin, and be absorbed by human tissues and cause internal radiation hazards. Due to its radioactive hazards and its characteristics in the environment, the monitoring of tritium is increasingly valued in radiation protection monitoring. The removal of high-concentration tritium in the gas is carried out by catalytic oxidation.

[0003] The high-humidity air detritiation technology adopted in the present invention combines catalytic oxidation detritiation technology, gas drying technology and gas cleaning technology. The catalytic oxidation detritiation technology is adopted to convert all the tritium therein into tritiated water; the drying tube drying technology is adopted to efficiently separate the gas and water in the airflow; the gas bubbling technology is adopted to clean the water vapor in the airflow and collect all the tritium components therein, thereby realizing efficient radon-tritium separation and environmental protection. Summary of the invention

[0004] An object of the present invention is to solve the problem of tritium removal in a tritium-involved environment and to provide at least the advantages described hereinafter.

[0005] In order to achieve these objects and other advantages according to the present invention, a system for detritium removal from high humidity air is provided, comprising:

[0006] a detritiation unit, which includes a gas booster pump, a flow controller, an inner tube of a drying tube, a catalytic reactor, an adsorber and a dew point meter connected in sequence through pipelines;

[0007] A water collecting unit, comprising a rotor flowmeter connected in sequence to the adsorber outlet, an outer sleeve of a drying tube, and a water collector;

[0008] Among them, after the tritium-containing air with a lot of water enters the detritiation unit, it is discharged after passing through the gas booster pump, flow controller, inner tube of the drying tube, catalytic reactor, adsorber and dew point meter in sequence, and the on-site air discharged from the adsorber outlet is collected after passing through the rotor flowmeter, the outer sleeve of the drying tube and the water collector in sequence.

[0009] Preferably, the catalytic reactor is a stainless steel tube with an inner diameter of DN150mm×1200mm, which is filled with a catalyst; the catalyst is Al2O3 plated with 1% Pd.

[0010] Preferably, an electric heating rod is arranged in the catalytic reactor; an aluminum silicate fiber insulation layer is arranged outside the catalytic reactor; and an armored thermocouple is inserted in the catalytic reactor.

[0011] Preferably, the drying tube is a stainless steel jacketed drying tube, the inner tube of which transfers tritium water from ambient air to the outer tube of the drying tube, and the gas output from the inner tube is only dry tritium-containing gas.

[0012] Preferably, the inlet of the flow controller is connected to the gas outlet of the gas booster pump through a pipeline, and the outlet of the flow controller is connected to the inlet of the inner tube of the drying tube through a pipeline; the inlet of the water collector is connected to the outlet of the outer sleeve of the drying tube through a pipeline.

[0013] Preferably, the outlet of the adsorber is connected to a tee, a first outlet of the tee is connected to a discharge pipe, and a dew point meter is connected to the discharge pipe; and a second outlet of the tee is connected to a rotor flowmeter.

[0014] Preferably, a first stop valve is provided on the pipeline connecting the inner tube of the drying tube and the catalytic reactor; a second stop valve and a third stop valve are provided on the pipeline connecting the catalytic reactor and the adsorber; a fourth stop valve is provided on the pipeline connecting the adsorber and the three-way pipe; a fifth stop valve is provided on the pipeline at the end of the detritus removal unit; and a sixth stop valve is provided on the pipeline at the end of the water collection unit.

[0015] Preferably, the system further comprises a gas filter connected to the pipeline and located upstream of the gas booster pump.

[0016] The present invention includes at least the following beneficial effects: the present invention adopts tritium-oxygen catalysis and gas-liquid separation technology to realize on-site cleaning of tritium; adopts electrical control technology for automatic control, reduces manual intervention, improves tritium removal efficiency, and ensures work quality. Its purpose is to timely remove tritium components in high-humidity air under high-humidity background air conditions, thereby realizing effective protection of the tritium-related environment.

[0017] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a structural principle diagram of the high humidity air detritium system of the present invention;

[0019] Figure 2 It is the schematic diagram of the test system;

[0020] Figure 3 This is the electrical schematic diagram of the high humidity air detritium system. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0022] It should be understood that terms such as “having”, “including” and “comprising” used herein do not specify the existence or addition of one or more other elements or combinations thereof.

[0023] Figure 1 A system for detritium removal from high humidity air according to the present invention is shown, comprising:

[0024] A detritium removal unit, which includes a gas booster pump 3, a flow controller 4, an inner tube of a drying tube 5, a catalytic reactor 8, an adsorber 11 and a dew point meter 14, which are sequentially connected through pipelines;

[0025] A water collecting unit, which includes a rotor flowmeter 13 connected to the outlet of the adsorber 11, an outer sleeve of the drying tube 5, and a water collector 6 in sequence;

[0026] Among them, after the tritium-containing air containing more water enters the detritiation unit from the gas inlet 1, it is discharged after passing through pumping (gas booster pump 3), gas flow control (flow controller 4), atmosphere drying (inner tube of drying tube 5), catalytic oxidation (catalytic reactor 8), water vapor absorption (adsorbent 11) and dryness measurement (dew point meter 14). Another way is to make the on-site air discharged from the outlet of the adsorber 11 pass through the rotor flowmeter 13, the outer sleeve of the drying tube 5, and the water collector 6 in sequence before being collected.

[0027] In the above technical scheme, the principle of detritium removal from high-humidity air is to first use a gas booster pump as the power of gas flow to force the air gas sample containing more water vapor and tritium to pass through the inner tube of the drying tube to remove water------the catalytic reactor fully oxidizes the tritium gas to form tritium water---the adsorber fully absorbs the tritium water---the dew point meter monitors the dryness of the terminal gas---the pipeline is discharged, and another auxiliary circuit (water collection unit) is to collect the moisture in the air precipitated from the drying tube into the water collector, that is, to use the system pressure after the main road is dried as the power of gas flow, and through the rotor flowmeter display control, the water vapor in the outer sleeve of the drying tube is forced to be collected in the water collector and then sent to the discharge pipeline through the carrier gas.

[0028] In the above technical solution, the catalytic reactor is a stainless steel tube with an inner diameter of DN150mm×1200mm, which is filled with a catalyst; the catalyst is Al2O3 plated with 1% Pd; the catalyst is used for catalytic oxidation to convert gaseous tritium into liquid tritium, and its conversion efficiency can reach more than 99%.

[0029] In the above technical scheme, an electric heating rod is arranged in the catalytic reactor; an aluminum silicate fiber insulation layer is arranged outside the catalytic reactor; an armored thermocouple is inserted in the catalytic reactor; considering the long-term use of the catalyst in this system, it is necessary to provide catalyst regeneration conditions, that is, it is necessary to configure a matching electric heating furnace, adopt a rod-type internal heating method, with an insulation resistance of more than 5MΩ and a heating power of about 1.5kw; an armored thermocouple is inserted in the center of the catalytic tube to facilitate the measurement and control of the working temperature of the catalyst, and the working temperature of the catalytic reactor is automatically controlled by a temperature controller; the purpose of heating is mainly to prevent the catalyst surface from being covered with a water film and affecting the catalytic efficiency, therefore, the heating temperature of the catalyst center can be maintained at about 100°C.

[0030] In the above technical solution, the drying tube 5 is a stainless steel jacketed drying tube, which is the PD-200 stainless steel jacketed drying tube produced by Perma Pure Corporation of the United States; the inner tube of the drying tube transfers the tritium water from the catalytic reactor to the outer tube of the drying tube, and the gas output from the inner tube is a water-free dry gas.

[0031] In the above technical solution, the inlet of the flow controller 4 is connected to the gas outlet of the gas booster pump 3 through a pipeline, and the outlet of the flow controller 4 is connected to the inlet of the inner tube of the drying tube 5 through a pipeline; after the gas is dried by the drying tube, its water content is extremely low, and the gas coming out of the inner tube of the drying tube 5 can be used as backwash gas to take away the water vapor in the outer tube of the drying tube;

[0032] The front end of the water collector 6 is connected to the outer sleeve outlet of the drying tube 5 and the rotor flowmeter 13; the outlet of the water collector is connected to the exhaust pipe of the system through a pipeline; in this way, the gas flow rate in the pipeline is controlled by the rotor flowmeter, and the main gas pressure is used as the power for the gas flow of the auxiliary system; the water vapor of the outer sleeve of the drying tube is sent to the water collector for collection, and a condenser is pre-installed outside the water collector to efficiently collect moisture in the background air, effectively improving the catalytic efficiency and service life of the catalytic reactor.

[0033] In the above technical solution, the outlet of the adsorber 11 is connected to a tee, a first outlet of the tee is connected to a discharge pipe, and a dew point meter 14 is connected to the discharge pipe; and a second outlet of the tee is connected to a rotor flowmeter 13 .

[0034] In the above technical solution, a first stop valve 7 is provided on the pipeline connecting the inner tube of the drying tube and the catalytic reactor; a second stop valve 8 and a third stop valve 9 are provided on the pipeline connecting the catalytic reactor and the adsorber; a fourth stop valve 12 is provided on the pipeline connecting the adsorber 11 and the three-way pipe; a fifth stop valve 15 is provided on the pipeline at the end of the detritus removal unit; and a sixth stop valve 16 is provided on the pipeline at the end of the water collection unit.

[0035] The above technical solution also includes a gas filter, which is connected to the pipeline and located upstream of the gas booster pump, and the gas inlet of the booster pump is connected to the gas filter outlet; the gas outlet of the booster pump is connected to the inlet of the flow controller; this is used as the power for the gas flow of the main detritus system; the gas booster pump adopts the GWSPC series oil-free scroll vacuum compressor produced by Shenyang Jiwei Application Technology Co., Ltd.; the function of the filter is to filter dust in the air and effectively protect the service life of the booster pump.

[0036] In the present invention, tritium oxygen catalysis and gas-liquid separation technology are used to achieve on-site cleaning of tritium; the working temperature of the catalytic reactor is controlled by a temperature controller to reduce manual intervention, improve the detritium efficiency, and ensure the work quality. The purpose is to be able to remove the tritium component in high-humidity air in time under high-humidity background air conditions, so as to achieve effective protection of the tritium-related environment.

[0037] The efficiencies of the catalytic reactor and the drying tube of the high humidity air detritium removal system of the present invention are tested below:

[0038] Catalytic efficiency test of catalytic reactor:

[0039] Will be equipped with 10 3 The Bq / L-level HT gas container is connected in series in front of the electric heating furnace with a built-in catalytic reactor. The effective volume of the container is 1L. The electric heating furnace can continuously heat the catalytic reactor. Room air is used as the flushing gas, and the flow rate is controlled to 1L / min. The HT carried enters the catalytic reactor and is catalyzed into HTO. After passing through the drying tube, it enters the bubbler and is collected by the bubbling liquid. The bubbler is filled with 30mL of pure water bubbling liquid. After running for 60 minutes, it is stopped and 1mL of bubbling liquid is taken for measurement with a liquid scintillation analyzer to calculate the catalytic efficiency. Table 1 shows the test results of the catalytic efficiency;

[0040] Table 1

[0041]

[0042] As can be seen from Table 1, when the catalyst is at room temperature (20°C), the catalytic efficiency can reach 32%. When the catalyst is heated to 50°C, the catalytic efficiency reaches 95%, which has begun to rise. At 100°C, the catalytic efficiency is close to 100%, so it is appropriate to control the catalytic temperature within the range of 50°C to 110°C.

[0043] Drying tube tritium water vapor separation performance test:

[0044] The principle of the test system is shown in Figure 2 , add 50mL of tritiated water into the bubbler 111, and introduce argon gas from the carrier gas tank 116. By bubbling, at room temperature 20°C, tritiated water vapor with a relative humidity of 90% to 98% is generated. This is used as the experimental gas source, and its tritium concentration value is stable at 1.6×10 6 Bq / m 3 The tritiated water vapor is passed into the drying tube 112, and the flow meter 115 controls the flow rate at 1L / min. The outlet is connected to the 1# ionization chamber 113. After measurement, the gas enters the drying tube to flush the gas path, taking away the water vapor that penetrates the tube wall. The outlet is connected to the 2# ionization chamber 114 for monitoring the tritiated water vapor for comparison. Table 2 shows the separation performance test of the drying tube (Bq / m 3 )

[0045] Table 2

[0046] Serial number Test time (min) 2# Ionization Chamber 1# Ionization Chamber 1 0 <![CDATA[1.6×10 5 ]]> <![CDATA[1.62×10 5 ]]> 2 20 <![CDATA[7.4×10 5 ]]> <![CDATA[1.63×10 5 ]]> 3 40 <![CDATA[9.7×10 5 ]]> <![CDATA[1.58×10 5 ]]> 4 60 <![CDATA[1.1×10 6 ]]> <![CDATA[1.49×10 5 ]]> 5 120 <![CDATA[1.1×10 6 ]]> <![CDATA[1.61×10 5 ]]>

[0047] The test results show that the drying tube has a good effect in separating tritium from water vapor.

[0048] It can also be seen from Table 2 that the tritiated water vapor cannot reach the outlet of the inner tube of the drying tube. For as long as 60 minutes, the reading of the 1# ionization chamber is always at the background level, indicating that there is no tritiated water vapor at the outlet of the inner tube of the drying tube.

[0049] Drying tube tritium permeability test:

[0050] System like Figure 2 As shown, no bubbling liquid was added to the bubbler, and the sampling flow rate was 1L / min. Argon was used as the drying tube flushing gas, the flow rate was controlled at 1L / min, and the test time was 140min. The results are shown in Table 3 Drying tube tritium permeability test (Bq / m 3 );

[0051] Table 3

[0052]

[0053]

[0054] The test results show that the tritium concentration in the dryer flushing airflow does not exceed the background and HT cannot pass through the inner tube of the dryer.

[0055] The electrical schematic diagram of the high humidity air detritium system is shown in Figure 3 . The contactor KM1, the stop button SBS1, and the start button SB1 are used to start and stop the main power supply, and they also have a relay protection function. The start and stop of the gas booster pump MS are realized by KM2, SBS2, and SB2, and are linked with all valves YVn, and have a relay protection function. A fuse FU is set for overcurrent protection of related electrical appliances in the system. The heating control of the electric furnaces EE1 and EE2 is automatically controlled for the operating temperature of the catalytic reactor and the adsorber respectively. The power expansion adopts solid-state relays SSR1 and SSR2. The temperature setting and automatic control are realized by the corresponding temperature controllers PT1 and PT2, and the start and stop are controlled by switches SA1 and SA2. The online display control of the gas flow is realized by the mass flow controller PQ. The display of the gas dryness is displayed by the dew point meter PD, and the 24V power supply required for the dew point sensor is provided by the auxiliary power supply.

[0056] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A system for removing tritium from high humidity air, characterized in that: include: a detritiation unit, which includes a gas booster pump, a flow controller, an inner tube of a drying tube, a catalytic reactor, an adsorber and a dew point meter connected in sequence through pipelines; A water collecting unit, comprising a rotor flowmeter connected in sequence to the adsorber outlet, an outer sleeve of a drying tube, and a water collector; Among them, after the tritium-containing air containing more water enters the detritium removal unit, it is discharged after passing through the gas booster pump, the flow controller, the inner tube of the drying tube, the catalytic reactor, the adsorber and the dew point meter in sequence, and the field air discharged from the adsorber outlet is collected after passing through the rotor flowmeter, the outer sleeve of the drying tube and the water collector in sequence; The inlet of the flow controller is connected to the gas outlet of the gas booster pump through a pipeline, and the outlet of the flow controller is connected to the inlet of the inner tube of the drying tube through a pipeline; The inlet of the water collector is connected to the outlet of the outer sleeve of the drying pipe through a pipeline; The outlet of the adsorber is connected to a tee, a first outlet of the tee is connected to a discharge pipe, and a dew point meter is connected to the discharge pipe; a second outlet of the tee is connected to a rotor flowmeter; A first stop valve is provided on the pipeline connecting the inner tube of the drying tube and the catalytic reactor; a second stop valve and a third stop valve are provided on the pipeline connecting the catalytic reactor and the adsorber; a fourth stop valve is provided on the pipeline connecting the adsorber and the tee; a fifth stop valve is provided on the pipeline at the end of the detritus removal unit; and a sixth stop valve is provided on the pipeline at the end of the water collection unit; The catalytic reactor is a stainless steel tube with an inner diameter of DN150mm×1200mm, which is filled with a catalyst; the catalyst is Al2O3 plated with 1% Pd; an electric heating rod is arranged in the catalytic reactor; an aluminum silicate fiber insulation layer is arranged outside the catalytic reactor; an armored thermocouple is inserted in the catalytic reactor; Also included is a gas filter connected to the pipeline and located upstream of the gas booster pump; The electrical principle of the system for detritium removal from high-humidity air is as follows: the contactor KM1, the stop button SBS1, and the start button SB1 realize the start and stop of the main power supply, and have the relay protection function; KM2, SBS2, and SB2 realize the start and stop of the gas booster pump MS, and are linked with all valves YVn, and have the relay protection function; a fuse FU is set for overcurrent protection of relevant electrical appliances in the system; the heating control of the electric furnaces EE1 and EE2 is automatically controlled for the working temperature of the catalytic reactor and the adsorber respectively, the power expansion adopts solid-state relays SSR1 and SSR2, the temperature setting and automatic control are realized by the corresponding temperature controllers PT1 and PT2, and the start and stop are controlled by switches SA1 and SA2; the online display control of the gas flow is realized by the mass flow controller PQ; the display of the gas dryness is displayed by the dew point meter PD, and the 24V power supply required by the dew point sensor is provided by the auxiliary power supply.

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