RU225400U1 - DEVICE FOR PURIFYING GASES FROM TRITIUM - Google Patents

Abstract

The utility model relates to the field of environmental and personnel protection, is intended for purifying air (gases) from gaseous tritium and can be used in gas purification systems of enterprises carrying out work with tritium-containing materials with the amount of tritium at all workplaces not exceeding 40 TBq (1000 Ci) and strict requirements for the amount of tritium released into the environment. The gas purification device includes coarse and fine purification circuits; Each circuit includes two receivers for receiving a gas environment contaminated with tritium, a tritium purification module, a tritium monitor, and two transfer pumps. The volumetric activity of tritium at the output of the coarse purification circuit is set so as to synchronize the purification cycles in the coarse and fine purification circuits. The utility model allows you to increase the effective time of use of cleaning equipment. 1 ill.

Description

The utility model relates to the field of environmental and personnel protection, is intended for purifying air (gases) from gaseous tritium and can be used in gas purification systems of enterprises carrying out work with tritium-containing materials with the amount of tritium at all workplaces not exceeding 40 TBq (1000 Ci) and strict requirements for the amount of tritium released into the environment.

A known system for purifying a gas mixture from tritium includes a first purification stage and a second purification stage connected by a pipeline; the first purification stage includes a first receiver, a first gas purification unit, a first transfer pump, the first receiver is connected by pipelines to the first gas purification unit operating in a closed cycle, and the first transfer pump; the second stage of purification includes a second receiver, a second gas purification unit, a second transfer pump, the inlet of the second receiver is connected to the output of the first transfer pump, the second receiver is connected by pipelines to a second gas purification unit operating in a closed cycle, and a second transfer pump that exhausts the purified gas in atmosphere. RF patent for utility model No. 59311, IPC G21F 9/02, 07/11/2006. This technical solution was adopted as a prototype.

The disadvantage of the prototype is the lack of synchronization of the duration of cleaning cycles of the system stages, which will inevitably lead to a situation where the reception of a contaminated gas environment from the process equipment by the cleaning system will be impossible, since the input receiver (first stage receiver) will be occupied with the purified mixture from the previous cycle, because the receiver the second stage is occupied by the mixture being purified in the process of cleaning if the cycle of the second stage has a longer duration than the cycle of the first stage, or the receiver of the first stage will be occupied by the mixture being in the process of cleaning if the cycle of the second stage is shorter than the cycle of the first stage . The technical means of the prototype do not allow selecting the degree of cleaning of the first stage in such a way as to equalize the duration of cleaning of both stages.

The technical result is an increase in the effective time of use of technological equipment due to the possibility of receiving an increased volume of a gaseous medium contaminated with tritium during the cleaning process due to duplication of receivers and achieving the same duration (synchronization) of coarse and fine cleaning cycles.

The technical result is achieved by the fact that in a device for purifying gases from tritium, which includes a coarse cleaning circuit and a fine cleaning circuit located in a sealed housing, each operating in a closed cycle; the coarse cleaning circuit includes a first receiver, a first gas cleaning unit and a first transfer pump; the first gas purification unit includes a first purification module and a first tritium monitor that monitors the achievement of a first tritium volumetric activity value; the first receiver is connected by separate pipelines to the first purification module, the first tritium monitor and the first transfer pump; the fine purification circuit includes a second receiver, a second gas purification unit and a second transfer pump that exhausts the purified gas into the atmosphere; the second gas purification installation includes a second purification module and a second tritium monitor that controls the achievement of a second value of tritium volumetric activity, the second value of tritium volumetric activity is fixed; the inlet of the second receiver is connected to the output of the first transfer pump, the second receiver is connected by separate pipelines to the second cleaning module, the second tritium monitor and the second transfer pump, the coarse cleaning circuit additionally includes a third receiver and a third transfer pump; the third receiver is connected by separate pipelines to the first purification module, the first tritium monitor and the first transfer pump; the fine purification circuit additionally includes a fourth receiver and a fourth transfer pump, which exhausts the purified gas into the atmosphere; the inlet of the fourth receiver is connected to the output of the third transfer pump, the fourth receiver is connected by separate pipelines to the second cleaning module, the second tritium monitor and the second transfer pump; receivers include solenoid valves at the outlet; the electromagnetic valves at the output of the first and third receivers are controlled by the first value of tritium volumetric activity; the electromagnetic valves at the output of the second and fourth receivers are controlled by the second value of tritium volumetric activity; The first value of the volumetric activity of tritium is adjustable, depends on the initial value of the volumetric activity of tritium and ensures equalization of the operating time of the coarse purification and fine purification circuits.

The essence of the utility model is illustrated by a drawing, where:

1 - first receiver;

2 - first cleaning module;

3 - first tritium monitor;

4 - first transfer pump;

5 - second receiver;

6 - second cleaning module;

7 - second tritium monitor;

8 - second transfer pump;

9 - third receiver;

10 - third transfer pump;

11 - fourth receiver;

12 - fourth transfer pump;

13 - sealed housing.

The device for purifying gases from tritium includes coarse and fine purification circuits placed in a sealed housing 13. The coarse cleaning circuit includes the first 1 and third 9 receivers, the first cleaning module 2, the first tritium monitor 3, the first 4 and third 10 transfer pumps. The fine cleaning circuit includes the second 5 and fourth 11 receivers, the cleaning module 6, the tritium monitor 7, the second 8 and fourth 12 transfer pumps.

Receivers (1, 5, 9, 11) are sealed tanks made of corrosion-resistant steel with an internal cavity volume of ~ 1 m ³ and have the ability to pump out the gaseous medium from the internal volume to a residual pressure of minus 990 mbar using transfer pumps. For the inlet and outlet of the gas environment, the receivers are equipped with solenoid valves. The pressure inside each receiver is controlled using a pressure gauge (not shown in the drawing).

The purification modules of both circuits (2, 6) are identical in design and are sets of means for the catalytic oxidation of molecular tritium located in the gaseous medium being purified and the subsequent capture of the resulting oxide on molecular sieves.

To control the volumetric activity of tritium (OAT), the device includes tritium monitors (3, 7): tritium monitor 3 controls the first volumetric activity of tritium - the coarse purification circuit OAT _gr , and tritium monitor 7 controls the second volumetric activity of tritium - the fine purification circuit OAT _fine . Based on the readings of tritium monitors, the receiver valves and the operation of treatment units are controlled

Transfer pumps (4, 8, 10, 12) are oil-free fore-vacuum pumps that ensure pumping of receivers to a residual pressure of no more than 1 mm Hg. Pumps 8, 12 exhaust purified gas into the atmosphere.

All components of the device are hermetically connected by pipes made of corrosion-resistant steel according to the drawing.

Both receivers of the coarse cleaning circuit (1, 9) have the ability to connect to the line of forevacuum exhausts from the process equipment.

Both receivers of the fine purification circuit (5, 11) have the ability to pump out the medium contained in them into the environment.

The device works as follows.

The cleaning process includes the following steps:

- intake of contaminated gas;

- rough cleaning;

- fine cleaning;

- release of purified gas.

In the initial state, the residual pressure inside all receivers (1, 5, 9, 11) should be no more than minus 990 mbar.

At the stage of inlet of the gas to be cleaned, the inlet valve of the receiver 1 is opened, allowing access of the medium from the line of tritium-contaminated forevacuum exhausts into the receiver. After filling the receiver 1 with a gas medium to be purified from tritium to a pressure not higher than minus 100 mbar, the inlet valve is closed. If at this point in time the process equipment continues to operate, then the inlet valve of the receiver 9 is opened.

At the coarse cleaning stage, after filling receiver 1, the blower of cleaning module 2 creates a flow of gaseous medium from the receiver into the cleaning module and again into the receiver, ensuring repeated pumping of the medium through the cleaning module. Inside the purification module, the medium first passes through a catalyst that converts molecular tritium into oxide, which in turn, when passing through a molecular sieve, is deposited on its granules, after which the gas medium, partially purified in this way from tritium, again enters receiver 1 and the process is repeated.

During the cleaning process, a sample of the medium is periodically taken from receiver 1 in order to measure the OAT in it: using the blower of tritium monitor 3, the medium from receiver 1 is pumped through the ionization chamber of the tritium monitor and again discharged into receiver 1.

After reaching the OAT value inside receiver 1 equal to OAT _gr - assigned for the coarse cleaning circuit, cleaning by the coarse cleaning module stops, the outlet valve of receiver 1 and the inlet valve of receiver 5 are opened and pump 4 pumps the medium from receiver 1 of the coarse cleaning circuit to receiver 5 of the fine circuit cleaning. After filling the receiver 5 with the cleaned medium to a pressure not higher than minus 100 mbar, the receiver valves are closed. After completing pumping of the medium from receiver 1, it is ready to receive the next portion of the medium from the line of tritium-contaminated forevacuum exhausts.

At the fine cleaning stage, the process of cleaning the contents of receiver 5 is similar to the process of cleaning the contents of receiver 1 with the difference that cleaning continues until the OAT value inside receiver 5 is equal to OAT _fine - assigned to the fine cleaning circuit, after which cleaning by fine cleaning module 6 stops, the output The receiver valve 5 is opened, and at the stage of releasing purified gas, the medium is pumped by pump 8 into the central pipe of the enterprise and then into the environment. After pumping the medium from receiver 5 is completed, the outlet valve of receiver 5 is closed and the receiver is again ready to receive medium from receiver 1.

The processes in the “receiver 9 - receiver 11” arm are completely similar to the processes in the above described “receiver 1 - receiver 5” arm.

As practice shows, the duration of the fine cleaning cycle is longer than the duration of the coarse cleaning cycle, therefore, with an equal number of receivers in both circuits, sooner or later there will come a time when both receivers of the coarse cleaning circuit are full, and the cleaning installation will not be able to service the process equipment until then until at least one receiver in the coarse cleaning circuit is free.

Increasing the number of receivers in the fine circuit (when, for example, for one receiver in the coarse circuit there are two or more receivers in the fine circuit) will solve the problem only temporarily, and still there will come a time when all the receivers in the fine circuit are full and It will be impossible to pump the medium from the receivers of the coarse purification circuit.

The problem can be solved by increasing the number of receivers and fine cleaning modules in the fine cleaning circuit; however, this means an increase in the cost of the installation, an increase in its overall dimensions and, importantly, an increase in the volume of untreated gaseous medium concentrated in the workshop.

To solve the problem, it is proposed to synchronize the operation of the coarse and fine cleaning circuits, i.e. equalize the duration of the corresponding cycles: by the time the cleaning of the medium in the receiver of the coarse cleaning circuit is completed, the corresponding receiver of the fine cleaning circuit also completes the cleaning cycle and is ready to accept the medium from the receiver of the coarse cleaning circuit. The OAT _tonk value is fixed and corresponds to the OAT value permitted by the State Sanitary and Epidemiological Supervision authorities for release into the environment at a specific enterprise (or less). Therefore, synchronization can be achieved by adjusting only the OAT _gr value depending on the initial OAT value.

Thus, with an OAT _ton value equal to 4.4⋅10 ⁵ Bq/m ³ , an initial OAT value equal to 10 ⁹ Bq/m ³ , and a pumping speed of 60 m ³ /h, the OAT _gr value is 6⋅10 ⁶ Bq/m ³ .

Further adjustment can be carried out automatically using information about the current OAT values of the gaseous medium in the modules of each circuit by recalculating and adjusting the OAT _gr to prolong the rough cleaning process.

In addition, redundancy of receivers creates a backup arm that receives contaminated exhaust from process equipment during the cleaning cycle in the filled arm.

Claims (1)

A device for purifying gases from tritium, including a coarse purification circuit and a fine purification circuit mounted in a sealed housing, each operating in a closed cycle; the coarse cleaning circuit includes a first receiver, a first gas cleaning unit and a first transfer pump; the first gas purification unit includes a first purification module and a first tritium monitor that monitors the achievement of a first tritium volumetric activity value; the first receiver is connected by separate pipelines to the first cleaning module, the first tritium monitor and the first transfer pump; the fine purification circuit includes a second receiver, a second gas purification unit and a second transfer pump that exhausts the purified gas into the atmosphere; the second gas purification installation includes a second purification module and a second tritium monitor that controls the achievement of a second value of tritium volumetric activity, the second value of tritium volumetric activity is fixed; the inlet of the second receiver is connected to the output of the first transfer pump, the second receiver is connected by separate pipelines to the second cleaning module, the second tritium monitor and the second transfer pump, characterized in that the coarse cleaning circuit includes a third receiver and a third transfer pump; the third receiver is connected by separate pipelines to the first purification module, the first tritium monitor and the first transfer pump; the fine purification circuit includes a fourth receiver and a fourth transfer pump, which exhausts the purified gas into the atmosphere; the inlet of the fourth receiver is connected to the output of the third transfer pump, the fourth receiver is connected by separate pipelines to the second cleaning module, the second tritium monitor and the second transfer pump; receivers include solenoid valves at the outlet; the electromagnetic valves at the output of the first and third receivers are controlled by the first value of tritium volumetric activity; the electromagnetic valves at the output of the second and fourth receivers are controlled by the second value of tritium volumetric activity; The first value of the volumetric activity of tritium is adjustable, depends on the initial value of the volumetric activity of tritium and ensures equalization of the operating time of the coarse purification and fine purification circuits.

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