CN103111211A - An iodine vapor distribution device capable of adding iodine on-line - Google Patents

Abstract

The invention provides an iodine vapor distribution device capable of adding iodine online. It consists of an iodine vapor generation system, a carrier gas preheating system, an online iodine addition system, and pipes and valves connecting the systems. The carrier gas preheating system includes an air compressor, a gas cylinder, a spiral tube and the first water bath. The iodine vapor generating system includes an iodine pool, an upper gas equalization plate, a carrier gas pipe, a lower gas equalization plate, a carrier gas diffusion nozzle, and a second water bath. The line iodine addition system includes a hopper, a ball valve, and a feed pipe. The invention provides an economical and reliable iodine vapor distribution system capable of meeting the continuous operation requirements of different working conditions for the performance experiment of the containment filtering and discharging system. The device of the present invention is also suitable for systems requiring continuous iodine supply for a long time in other fields such as chemical industry.

Description

An iodine vapor distribution device capable of adding iodine on-line

technical field

The invention relates to a device for generating and distributing iodine vapor.

Background technique

The containment filter and discharge system is a system set up to ensure the integrity of the containment. When a serious accident of core meltdown occurs, the containment filter and discharge system will release the gas in the containment by active pressure relief. After washing and filtering, it is discharged into the environment to achieve the purpose of preventing the overpressure of the containment vessel, reducing the release of radioactive substances into the environment as much as possible, and reducing the radiation dose of the public from accidents. As one of the fission products, 131I is easily leaked from defective fuel elements and is highly radioactive. The amount released into the environment has been used as a standard to measure the severity of accidents. In order to reduce the consequences of serious accidents , the radioactive iodine in the containment needs to be removed through the filtration and discharge system, so the iodine removal performance of the filtration and discharge system is a necessary work to verify its reliability and safety.

Iodine is solid at room temperature. When a severe reactor accident occurs, the iodine produced mainly exists in the containment vessel in gaseous form. As the accident progresses, the pressure inside the containment vessel gradually increases. When the pressure is higher than the theoretical limit (0.45 MPa) to start the filter and discharge system for discharge and pressure relief. The autonomous operation time of the filter and discharge system is not less than 24 hours. The experimental circuit of the test circuit can stably and continuously provide a certain concentration of high-pressure iodine vapor for a long time (more than 24 hours), which requires a set of devices that can provide a certain concentration of high-pressure iodine vapor. The current conventional method is to mix high-purity nitrogen with a certain amount of iodine to prepare iodine vapor with the required concentration, then store it in a high-pressure steel cylinder and transport it to the gas environment. This method can provide continuous and relatively stable iodine vapor, but However, this method has major disadvantages: firstly, the process is complicated, and the cost of preparing and storing iodine vapor is too high; secondly, due to the limited filling gas of the steel cylinder, multiple steel cylinders need to be prepared for long-term continuous use, and the steel cylinders are replaced frequently. Not suitable for long-term continuous use. In addition, there have been certain research results on iodine vapor generating devices at home and abroad. In the patent documents whose patent application numbers are 9827605.7, 98237990.0 and 02209679.5, a kind of iodine vapor generating device using resistance wire heating is disclosed. Carry the iodine vapor that produces with bubbling method, in order to use; In the patent document that the patent application number is 200710158294.0 also discloses a kind of rapid continuous iodine supply device, describes described iodine supply device with the form of system block diagram, but does not Do any description of the structure of the iodine generator, and the above-mentioned several iodine supply devices are designed for the oxygen-iodine laser. The long-term (24 hours) continuous work requirement required by the experimental circuit of the filtration and emission system; in addition, cold helium is used as the carrier gas, and the helium coil is directly above the heating resistance wire. If the heating is insufficient, the cold helium The gas will disturb the temperature in the generator, break the dynamic equilibrium process established in the iodine generator, thereby affecting the performance of the iodine generator, and causing the instability of the iodine outlet concentration; finally, the iodine steam generator adopts flange connection, Large volume and weight, inconvenient to disassemble. In the patent document with the patent application number 201020132053.6, a device for disposing iodine vapor is disclosed. The iodine vapor generating device adopts the method of heating with a heating belt, and uses nitrogen as a carrier gas to carry the generated iodine vapor to a predetermined pressure. system, but the device does not describe the mixing process of carrier gas and iodine vapor, nor does it mention the method of on-line iodine addition, and it is impossible to determine the working status of the distribution device during continuous operation.

Contents of the invention

The object of the present invention is to provide a kind of iodine vapor dispensing device that can be used for online iodine addition and can be used continuously and stably for a long time.

The iodine vapor distribution device capable of adding iodine on-line of the present invention is composed of an iodine vapor generating system, a carrier gas preheating system, an on-line iodine addition system, and pipelines and valves connecting the various systems;

The carrier gas preheating system includes an air compressor 25, a gas storage bottle 24, a spiral tube 3 and a first water bath 19, the air compressor 25 is connected with the gas storage bottle 24, and the gas storage bottle 24 is connected with one end of the spiral tube 3, The other end of the spiral tube 3 is connected with one end of the three-way valve 4, and the spiral tube 3 is placed in the first water bath 19;

Described iodine vapor generation system comprises iodine pool 13, upper average gas plate 14, carrier gas pipe 15, lower average gas plate 16, carrier gas diffusion nozzle 18, the second water bath 20, upper average gas plate 14, lower average gas plate 16 respectively Be arranged on the top and bottom of the iodine pond 13 inside, the carrier gas diffusion nozzle 18 is positioned at the bottom of the lower uniform gas plate 16 and is connected with the carrier gas pipe 15, the iodine pond 13 is placed in the second water bath 20, and the top of the iodine pond 13 has an outlet The trachea 21, the upper air equalizing plate 14 and the lower air equalizing plate 16 are distributed with several circular holes;

Described on-line iodine addition system comprises feeding hopper 8, spherical valve 10, feed pipe 11, and spherical valve 10 is arranged between feeding hopper 8 and feeding pipe 11, and feeding pipe 11 is connected to the bottom of iodine pool 13, and hopper 8 The upper part of the connection balance air pipe 5;

The other two ends of the three-way valve 4 are respectively connected to the carrier gas pipe 15 and the balance gas pipe 5 .

The iodine vapor distribution device that can add iodine on-line of the present invention can also include:

1. An exhaust valve 6 is provided on the hopper 8 .

2. The circular holes on the lower air equalizing plate 16 are located on the circumferences with different diameters close to the center.

3. The circles on the upper gas equalizing plate 14 are located on the circumferences of different diameters close to the outer periphery.

4. The feeding hopper 8 is composed of upper and lower parts, and the upper and lower parts are connected by a quick joint 7 .

The invention provides an economical and reliable iodine vapor distribution system capable of meeting the continuous operation requirements of different working conditions for the performance experiment of the containment filtering and discharging system. The device of the present invention is also suitable for systems requiring continuous iodine supply for a long time in other fields such as chemical industry.

The beneficial effects that the present invention can realize include:

1. It can realize the continuous and stable supply of iodine vapor for a long time, and ensure the stable concentration of iodine vapor at the outlet of the system.

2. It can meet the distribution requirements of various concentrations of iodine vapor, and the concentration can be adjusted within a large range.

3. It can add iodine online, which can reduce the initial amount of iodine, so that the volume and weight of the iodine vapor generating device can be reduced to meet the

Requirements for miniaturization of iodine vapor generators.

4. Using water bath heating can precisely control the temperature inside the carrier gas and iodine pool, without adding insulation materials.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of the present invention.

Fig. 2 is the overall structure of the iodine vapor generating device, the flow diagram of the internal mixed gas and the schematic diagram of the feeding device.

Figure 3(a) is a partial enlarged view of the upper equalizing orifice plate; Figure 3(b) is a partial enlarged view of the lower equalizing orifice plate.

Fig. 4(a) is a partial enlarged view of the carrier gas diffusion nozzle; Fig. 4(b) is a bottom view of Fig. 4(a).

Detailed ways

The present invention will be further described below with reference to accompanying drawing

As shown in Figure 1, an iodine vapor distribution device capable of adding iodine online is composed of an iodine vapor generating system, a carrier gas preheating system, an online iodine adding system, and pipes and valves connecting each device. The air compressor 25 is connected to the gas cylinder 24, the outlet of the gas cylinder is connected to the flowmeter 26, the flowmeter 26 is connected to the needle valve 1, one end of the spiral tube 3 is connected to the needle valve 1, and the other end is connected to the three-way valve 4 , the other two ends of the three-way valve are respectively connected with the air intake pipe 15 and the balance air pipe 5, the other end of the air intake pipe 15 is connected to the iodine vapor generator, and the other end of the balance air pipe 5 is connected to the charging system. Before the system runs, the air compressor 25 runs to store a certain pressure of compressed gas in the gas cylinder 24, and at the same time set the temperature of the water bath 19 and water bath 20 to the required value, when the temperature reaches the set value, the water bath automatically stops heating . When the system is in normal operation, the dry compressed air carrier gas enters the spiral tube 3 to be heated to the required temperature through the needle valve 1 to adjust the flow rate, and enters the iodine pool 13 through the three-way valve 4 and the intake pipe 15, and the carrier gas passes through the diffusion nozzle 18 forms a radial radiant airflow, which is mixed with the iodine vapor produced, and the mixed gas flows upward through the annular gap between the diffusion nozzle 18 and the iodine pool 13, and then passes through the lower uniform pore plate 16 and the upper average pore plate 14, and then passes through the air outlet pipe 21 and the upper uniform pore plate 14. Needle valve 22 regulates access to the iodine system.

Fig. 2 shows the structural representation of the iodine pool 13 and the charging system of the iodine vapor generating device, the iodine pool 13 of the iodine vapor generating device is a vertical tank, a cylindrical cavity, and its top is welded with an air intake pipe 15 and an air outlet pipe 21 , Pressure gauge 9 and thermocouple 12. The iodine pool 13 is not integral, but is divided into upper and lower parts, and is connected with a quick connector 17 in the middle to facilitate disassembly during maintenance. The air inlet pipe 15 enters the vertical tank body through the top of the vertical tank body 13, and passes through the upper air-evening plate 14 and the lower air-evening plate 16 in turn, and its end is welded together with the diffusion nozzle 18, and maintains the diffusion nozzle and the iodine pool 13 Leave a gap at the bottom to allow room for the added iodine particles. The upper even gas plate 14 and the lower even gas plate 16 are welded to the inner wall of the iodine pool through its outer circumference, and several round holes are uniformly distributed on the circumference of the upper even gas plate 14 with different diameters, and the lower even gas plate 16 is close to Several circular holes are evenly distributed on the circumference of different diameters at the center, as shown in Fig. 3(a)-(b). The balance air pipe 5 bottom in the charging system is fixed on the top of the hopper 8 by welding, in order to balance the pressure inside the iodine pool during feeding. The feeding hopper 8 is divided into upper and lower parts, and the middle is connected with a quick joint 7, so that when feeding, it is convenient to disassemble and shorten the feeding time. An exhaust pipe is also connected to the top of the feed hopper 8, and an exhaust valve 6 is arranged on the exhaust pipe to remove residual gas in the feed pipe after feeding. The lower part of feed hopper 8 is connected with ball valve 10 by pipeline, and ball valve 10 is connected with feed pipe 11 afterwards, and the bottom of feed pipe 11 and iodine pool 13 is welded together, and feed pipe mouth should be lower than diffusion nozzle 18, so as not to When iodine is added, the iodine particles are blocked by the annular gap. Before the iodine vapor generating device works, it is necessary to add a certain amount of iodine particles into the iodine pool 13 through the feeding device as the raw material for producing iodine vapor. When initially adding iodine, there is no need to balance the gas source, because the inside of the feeding hopper 8 and the iodine pool 13 are uniform. For normal pressure, iodine particles can rely on gravity to enter the inside of the iodine pond, and the maximum amount of added iodine particles should ensure that its height does not submerge the diffusion nozzle 18, so as not to block the circular holes on the diffusion nozzle. The diffuser nozzle 18 is in the shape of a semicircle, and several round holes are distributed on its surface, so that the carrier gas can pass through in a radial shape, and its structural schematic diagram is shown in Figure 4(a)-(b). As more and more iodine vapor is taken away, the amount of iodine in the iodine pool becomes less and less. When the amount of iodine is reduced to a certain extent, the iodine vapor carried by the carrier gas can no longer meet the iodine requirements of the iodine system. At this time, it is necessary to add iodine to the iodine pool through the feeding device. When adding iodine, first open the quick joint 7, add a certain amount of iodine in the hopper 8, quickly tighten the quick joint 7, then when the three-way valve 4 is switched to the balance gas pipe 5, open the ball valve 10, due to the iodine pool 13 insides stop gas supply, so now the pressure in the hopper 8 is greater than the inside of the iodine pond, and the added iodine can enter the inside of the iodine pond 13 smoothly. When the feeding is finished, quickly close the ball valve 10, switch the three-way valve 4 to the intake pipe 15, and then the iodine steam generator starts working again. At this time, there is a part of gas remaining in the feeding pipeline 11 and the inside of the feeding hopper 8, and the exhaust gas is opened. Valve 6, get rid of these gases.

The iodine vapor generation system of the present invention is composed of an iodine pool 13, an upper gas equalizing plate 14, a carrier gas pipe 15, a lower gas equalizing plate 16, a quick connector 17, a carrier gas diffusion nozzle 18, a precision pressure gauge 9, a thermocouple 12, a temperature control The composition of the water bath 20 aims to supply iodine vapor continuously and stably for a long time.

The output of iodine vapor is related to the temperature and pressure inside the iodine pool 13. When the temperature and pressure were fixed, the sublimation and desublimation of iodine in the iodine pool 13 would reach a dynamic equilibrium process, so when the temperature and pressure inside the iodine pool 13 maintained When constant, the amount of iodine vapor produced per unit time inside the iodine pool 13 is constant, and there is the following relationship between the amount of carrier gas and the amount of iodine vapor carried. The amount of iodine vapor carried by the initial carrier gas increases with the increase of the flow rate of the carrier gas, and this is because the amount of iodine vapor carried by the carrier gas per unit time is less than the amount of iodine vapor produced by iodine sublimation per unit time in the iodine pool 13 internal units. ; After continuing to increase the flow rate of the carrier gas to a certain value, the amount of iodine vapor carried out reaches a maximum value, and then remains stable. At this time, if the flow rate is continued to be increased, the amount of iodine vapor carried out will not increase. At this stage, the amount of iodine vapor carried by the carrier gas per unit time is greater than the amount of iodine vapor produced by iodine sublimation per unit time inside the iodine cell 13 . Therefore, can control the amount of the iodine vapor carried by the carrier gas by two methods: keep the iodine cell 13 internal temperature and pressure constant, control the amount of the iodine vapor carried by the carrier gas by controlling the flow rate of the carrier gas, so that the carried out The amount of iodine vapor is stabilized at the required value; keep the carrier gas flow constant, and control the iodine vapor amount generated by controlling the temperature and pressure inside the iodine pool 13, the iodine vapor amount carried out can also be stabilized at the required value . The iodine vapor generating device is an airtight structure. During the operation of the device, the hot carrier gas passes through the carrier gas pipe 15 to form a radial air flow through the diffusion nozzle 18, and then mixes with the iodine vapor generated in the iodine pool, and then the mixed gas is diffused. The annular gap between the nozzle 18 and the iodine pool 13 flows to the upper part of the iodine pool. Since the carrier gas can reach the same temperature as the inside of the iodine pool after preheating, the carrier gas will not disturb the temperature inside the iodine pool, and the iodine pool can always be maintained. An established dynamic balancing process within the pool. When the mixed gas flows upwards through the annular gap, it first passes through the lower gas-distributing plate 16. The lower gas-distributing plate 16 has two round holes near the center. It changes the flow of the mixed gas and also makes the mixed gas The concentration becomes more uniform. After passing through the lower gas uniform plate 16, the mixed gas continues to flow upwards and reaches the upper gas uniform plate 14. The upper gas uniform plate 14 has two rows of uniform circular holes on the circumference of different diameters close to the periphery, which is used to change the mixing for the second time. The flow of the gas, so that the gas is mixed evenly again, and the upper and lower gas equalization plates are installed to fully mix the carrier gas and iodine vapor, thereby ensuring the stability of the iodine vapor concentration at the outlet. After passing through the upper uniform gas plate 14, the mixed gas flows out of the iodine pool 13 through the outlet pipe 21. On the top of the iodine pool 13, measuring points for pressure and temperature are installed. During normal operation, precision pressure gauge 9 and thermocouple 12 can monitor the pressure and temperature inside the iodine pool at any time, so as to avoid large fluctuations in the temperature and pressure inside the iodine pool. Fluctuations, resulting in fluctuations in iodine vapor production. The iodine pond 13 is heated by a water bath. The advantage of this method is that the temperature inside the iodine pond 13 can be precisely controlled to a certain value without additional insulation measures; the temperature inside the iodine pond 13 can be changed flexibly by changing the temperature of the water bath. The temperature is used to control the output of iodine vapor to meet the needs of iodine vapor concentration in different working conditions.

The iodine addition system of the present invention is made up of balance air pipe 5, exhaust valve 6, quick connector 7, feeding hopper 8, spherical valve 10, feed pipe 11. For easy disassembly and saving feeding time, the feeding hopper 8 is composed of upper and lower parts, which are connected with quick connector 7. The upper part of the hopper 8 is connected with the balance gas pipe 5, and the balance gas pipe 5 is used to provide a balance gas source to balance the pressure inside the iodine pool 13 and ensure that the added iodine can enter the iodine pool 13 smoothly. Spherical valve 10 is in normally closed state, in order to isolate iodine pool and iodine adding system, opens when adding iodine, promptly closes after adding iodine. The exhaust valve 6 is in a normally closed state, and is opened after the iodine addition process is completed to discharge the gas remaining in the hopper, so as to prevent the remaining gas from being ejected when the quick connector is opened for the next iodine addition, so as to ensure the safety of the next iodine addition conduct. Because iodine vapor is poisonous, the above-mentioned iodine vapor generating device and online iodine addition system are placed in a fume hood to avoid possible leakage of iodine vapor from spreading indoors.

The carrier gas preheating system of the present invention is used for heating the carrier gas, because the cold carrier gas enters the inside of the iodine pool 13, it will disturb the temperature inside the iodine pool 13, thereby breaking the established dynamic equilibrium process inside the iodine pool 13, and the carrier gas Preheating can ensure that the temperature of the carrier gas is consistent with the temperature in the iodine generator, thereby maintaining the dynamic balance inside the iodine pool 13 and ensuring the stability of the iodine vapor concentration at the outlet of the iodine generator. The above-mentioned carrier gas preheating device is composed of a needle valve 1 , a spiral tube 3 , a temperature-controlling water bath 19 and a thermocouple 27 . The needle valve 1 can adjust the flow rate of the carrier gas in a wide range to meet the requirements of different working conditions. The preheating tube 13 is a spiral copper tube, and the use of a spiral tube can increase the contact area between the preheating tube and water, thereby enhancing the heat exchange capacity; the reason for choosing the copper tube is that the heat transfer coefficient of the copper tube is large, and the heat transfer rate is high. Strong ability and corrosion resistance. The thermocouple 27 is used to monitor the temperature of the outlet of the carrier gas, used in conjunction with the thermocouple 12 to ensure that the carrier gas and the inside of the iodine cell always maintain the same temperature.

The distribution circuit is mainly composed of an air compressor 25, a gas storage bottle 24, a flow meter 26, a needle valve 1, a carrier gas preheating device and an iodine vapor generating device. The air compressor 25 provides air with a certain pressure to the gas cylinder 24, and the compressed air enters the carrier gas preheating device 2 after being adjusted to the required flow rate by the needle valve 1, and the carrier gas is heated to the required temperature and enters the iodine pool 13 , take the generated iodine vapor out to the iodine-requiring system.

Claims (9)

1. An iodine vapor distribution device that can add iodine on-line is characterized in that it is made up of iodine vapor generation system, carrier gas preheating system, on-line iodine addition system and pipelines and valves connecting said systems; The carrier gas preheating system includes an air compressor (25), a gas storage bottle (24), a spiral tube (3) and a first water bath (19), the air compressor (25) is connected to the gas storage bottle (24), The gas cylinder (24) is connected to one end of the spiral tube (3), the other end of the spiral tube (3) is connected to one end of the three-way valve (4), and the spiral tube (3) is placed in the first water bath (19); The iodine vapor generation system includes an iodine pool (13), an upper gas equalization plate (14), a carrier gas pipe (15), a lower gas equalization plate (16), a carrier gas diffusion nozzle (18), a second water bath (20), The upper gas equalizing plate (14) and the lower gas equalizing plate (16) are respectively arranged on the upper and lower parts inside the iodine pool (13), and the carrier gas diffusion nozzle (18) is located under the lower gas equalizing plate (16) and connected to the carrier gas tube (15) Connection, the iodine tank (13) is placed in the second water bath (20), the upper part of the iodine tank (13) has an outlet pipe (21), an upper gas equalization plate (14) and a lower gas equalization plate (16) There are several circular holes distributed on it; The online iodine addition system includes a hopper (8), a spherical valve (10), and a feeding pipe (11), and the spherical valve (10) is arranged between the feeding hopper (8) and the feeding pipe (11). The pipe (11) is connected to the bottom of the iodine pool (13), and the upper part of the hopper (8) is connected to the balance gas pipe (5); The other two ends of the three-way valve (4) are respectively connected to the carrier gas pipe (15) and the balance gas pipe (5). 2. The iodine vapor distribution device capable of adding iodine online according to claim 1, characterized in that: the hopper (8) is provided with an exhaust valve (6). 3. The iodine vapor distribution device capable of adding iodine online according to claim 1 or 2, characterized in that: the circular holes on the lower gas equalizing plate (16) are located on circles with different diameters close to the center. 4. The iodine vapor distribution device capable of adding iodine online according to claim 1 or 2, characterized in that: the circles on the upper gas equalization plate (14) are located on circles with different diameters close to the outer periphery. 5. The iodine vapor distribution device capable of adding iodine online according to claim 3, characterized in that: the circles on the upper gas equalizing plate (14) are located on circles with different diameters close to the outer periphery. 6. The iodine vapor distribution device capable of adding iodine online according to claim 1 or 2, characterized in that: the feeding hopper (8) is composed of upper and lower parts, and the upper and lower parts are connected by a quick joint (7). 7. The iodine vapor distribution device capable of adding iodine online according to claim 3, characterized in that: the feeding hopper (8) is composed of upper and lower parts, and the upper and lower parts are connected by a quick joint (7). 8. The iodine vapor distribution device capable of adding iodine online according to claim 4, characterized in that: the feeding hopper (8) is composed of upper and lower parts, and the upper and lower parts are connected by a quick joint (7). 9. The iodine vapor distribution device capable of adding iodine online according to claim 5, characterized in that: the feeding hopper (8) is composed of upper and lower parts, which are connected by a quick connector (7).

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