JPS5937500A - Radioactive gaseous waste processing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a refrigeration cycle in which the load fluctuates greatly when treating radioactive exhaust gas from the main condenser, and is capable of achieving stable control over a complete load failure and is compact. and a radioactive gas waste treatment device that can be integrated.

[Technical background of the invention]

The exhaust gas precooler and exhaust gas dryer used in radioactive gas waste treatment equipment in nuclear power plants play the following roles.

In other words, the steam generated in the nuclear reactor contains hydrogen gas produced by radiolysis of water and radioactive elements such as Kr and X, which are condensed in the main condenser.
A portion remains as a non-condensable gas.

The gas is reduced to a safe radioactive concentration and released into the atmosphere through a stack.

That is, as shown in FIG. 1, exhaust gas is drawn from the main condenser 1 by a steam air extractor 2, and a recombiner 3 is provided to remove the aforementioned hydrogen gas.

Since the gas flowing out of the recombiner 3 is high-temperature superheated steam, the temperature in the condenser 4 is approximately 49°C in consideration of the effect on downstream equipment.
Lower the temperature to

On the downstream side is a process for removing Kr and Xs.

Therefore, an exhaust gas precooler 6 is provided to prevent high temperature air from flowing downstream and to reduce the capacity of the exhaust gas dryer 5 on the downstream side.

The exhaust gas precooler 6 turns the air into saturated air at about 10°C, and
Cooled to around -30°C using the aforementioned exhaust gas dryer 5 (dehumidified)
The activated carbon adsorption tower 7 holds [y,

By the way, the reason why the precooler 6 and the exhaust gas dryer 5 are separated is that the heat load on the exhaust gas dryer 5 becomes large and the operating time is shortened.

Here, the refrigeration cycle of the cooler 9 and the refrigerator 10 will be briefly explained with reference to FIGS. 2 and 3.

In FIG. 2, the compressor 11 compresses the refrigerant gas to a high temperature.
It is sent to the condenser 12 as a high-pressure gas.

The condenser 12 condenses and liquefies the high pressure gas and sends it as a liquid refrigerant to the expansion valve 13a.

The expansion valve 13α adiabatically expands the liquid refrigerant through its throttling action, and uses the liquid refrigerant as a low-temperature, low-pressure refrigerant in the evaporator 1.
Send to 4.

In the evaporator 14, the refrigerant absorbs heat from the artificial air α, evaporates, becomes a gas, and returns to the compressor 11 again.

Moreover, the air l flowing out of the evaporator 14 is supplied to a predetermined downstream side.

The expansion valve is the thermoelectric expansion valve 13cy shown in FIG. 2 or the thermoelectric expansion valve 134cy shown in FIG. Control using.

In the case of the temperature-type expansion valve 13cL shown in FIG. 2, the opening/closing control of the expansion valve 13α is performed using changes in the volume of the fluid contained in the temperature-sensitive tube 16 provided in the refrigerant pipe 15 on the outlet side of the evaporator 14. It is something to do.

On the other hand, the thermoelectric expansion valve 13a shown in FIG. 13! This is to be sent to A.

Next, a refrigeration system used in the conventional exhaust gas precooler 6 and exhaust gas dryer 5 will be explained with reference to FIGS. 4 and 5.

In other words, the freezing device has many tubes 2 inside the container 21.
2 and fins 23 are provided.

Air flows in from an air port 25 provided at the bottom of the container 21, is guided into the cooling section 24 by a baffle plate 26, and is supplied downstream from an air outlet 27 provided at the top of the container 21.

The refrigerant passes from the refrigerant population 28 through the refrigerant pipe 29 to the distributor 30
and is distributed to each tube 22.

After the refrigerant exchanges heat, it returns to the compressor 11 from the collecting pipe 31 through the refrigerant pipe outlet 32.

Further, the drain water condensed in the container 21 is discharged from the drain 33 to other systems.

[Problems with background technology]

The above-mentioned refrigeration devices are installed in pairs in the exhaust gas precooler 6 and the exhaust gas dryer 5, one each.

The exhaust gas precooler 6 has a calorific value of about 3000 kcal/h in order to convert air at about 50°C into saturated air at 0° to 10°C, and uses Freon for medium temperature as a refrigerant.

On the other hand, the exhaust gas dryer 5 lowers the temperature of the air that has flown out of the exhaust gas precooler 6 to about 20 to 25 degrees Celsius (the dew point is 10 degrees Celsius) due to the temperature rise in the pipes along the way to -30 degrees Celsius, and the amount of heat is It takes about 1000 kcal/h.

In addition, low-temperature Freon is used as a refrigerant.

Therefore, when considered from the viewpoint of social needs such as effective utilization of the installed area within a nuclear power plant, reduction in the number of maintenance machines, and energy conservation, the conventional device has problems that go against the grain.

[Purpose of the invention]

The present invention has been made to solve the above problems,
It is an object of the present invention to provide a radioactive gas waste processing device that can reduce the installation area, facilitate maintenance, and reduce the number of refrigerators.

[Summary of the invention]

In order to achieve the above object, the present invention introduces the radioactive exhaust gas extracted from the main condenser by an air bleeder to a recombiner, lowers its temperature in the condenser, passes through a precooler and a dryer, and then passes it through an activated carbon adsorption tower. In a radioactive gas waste processing equipment that removes radioactive exhaust gas and releases it into the atmosphere from a stack, the precooler and dryer are replaced with an integrated precooling/dehumidifier to provide precooling and dehumidification functions with a single refrigeration system. This is a radioactive gas waste treatment equipment designed to

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 6 and 7.

In FIG. 6, a steam type air extractor 2 is connected to the main condenser 1, and a recombiner 3 and a condenser 4 are connected downstream of the air extractor 2.

On the downstream side of the condenser 4, a pre-cooling and dehumidifying section 6 is integrated.
A precooler/dehumidifier 50 of the stand is connected.

A refrigerator 10 is connected to each precooler/dehumidifier 50.

The downstream side of the precooler/dehumidifier 50 is connected to an activated carbon adsorption tower 7, and the activated carbon adsorption tower 7 is connected to a stack.

The precooler/dehumidifier 50 is an airtight container 51 as shown in FIG.
A pre-cooling section 52 and a dehumidifying section 53 are disposed in the lower part and the upper part.

In addition, a refrigerant pipe 54 is provided from the bottom to the top of the container 51.
is provided, and the tip of the refrigerant pipe 54 is connected to the distributor 30.

The distributor 30 branches five tubes 22.

A first buckle plate 59 is attached to the lower end of the pre-cooling section 52, and a second buckle plate 60 is attached to the upper end.

A third baffle plate 62 is attached to the upper end of the dehumidifying section 53.

A drain receiver 61 is provided below the dehumidifying section 53.

The drain receiver 61 connects the upper end of the drain pipe 57, and the end of the drain pipe 57 passes through the lower part of the container 51.

A drain pipe 58 is connected to the lower end of the container 51, and an air inflow pipe 55 is connected to the lower side of the container 51, and an air outflow pipe 56 is connected to the upper side.

In the above device, saturated air at about 50° C. enters the container 51 from the inflow pipe 55 and is blocked by the first baffle plate 59 to prevent air from escaping from the surroundings.
Air is guided to the precooling section 52.

The air that has passed through the pre-cooling section 52 is guided to the dehumidifying section 53 located at the top at a temperature of about 10.degree.

As shown by the arrow, the second baffle plate 60 and the drain receiver 61 cause the air to flow in a meandering manner, pass through the dehumidifying section 53, and be supplied downstream from the outflow pipe 56.

The sixth baffle brake 62 prevents air from going outside the dehumidifying section 53.

On the other hand, the flow of refrigerant is as follows: compressor 11 condenser 12 expansion valve 13
The water flows from the lower part of the container 51 to the upper part.

The refrigerant uniformly distributed into five pipes through the distributor 30 is controlled to a temperature of -30°C when it enters the dehumidifying section 53, and the liquid refrigerant is controlled to reach a temperature of about -15° C. at the outlet of the dehumidifying section 53. .

The temperature when entering the pre-cooling section 52 and exiting from the pre-cooling section 52 is controlled to be approximately ±0.degree.

Further, if the dehumidifying operation is continued, frost forms on the dehumidifying section 53.

Defrosting is carried out at certain intervals, but at that time the system is transferred to one of the remaining three machines, and the one that has been operating until now performs the defrosting process in the following procedure.

After exiting the compressor 11 , the hot gas passes through the refrigerant pipe 54 inside the container 51 from the hot gas bypass line to melt frost on cooling fins, etc., and is discharged from the drain pipe 57 to the outside of the container.

Also, about 3 t/H of condensed water flows out of the pre-cooling section 52 and is discharged to the outside of the container 51 through the drain pipe 58.

Due to the above-mentioned actions, the freezing operation and defrosting operation are repeated, but in the above embodiment, the best results were obtained with the 15H cycle.

This is because if the length is too long, frost formation will increase, heat exchange will deteriorate, and at the same time, pressure loss will become large and the air flow balance in the system configuration will be lost.

In addition, the present invention is conventionally designed for 2 to 300 m after exiting the exhaust gas precooler.
Since an exhaust gas dryer was installed downstream, the temperature rose between them and the sensible heat increased, but by directly performing precooling and dehumidification, the heat transfer area of the dehumidifying part can be reduced by approximately 0%.

〔Effect of the invention〕

As described above, the present invention provides a precooling/dehumidifier in place of the conventional exhaust gas precooler and eliminates the exhaust gas dryer that was conventionally installed on the downstream side.

Therefore, compared to the case where the conventional exhaust gas precooler and exhaust gas dryer are installed far apart, the total amount of heat is approximately 10% smaller, and two refrigerators for the conventional precooler and three refrigerators for the dryer are required. The refrigerator that was
It can be reduced to a table.

Furthermore, the layout within the nuclear power plant also has the advantage of requiring only 315 square meters of installation space compared to conventional systems.

[Brief explanation of the drawings] Figure 1 is a system diagram showing a conventional gaseous waste treatment device, Figure 2
The figure is a system diagram showing a refrigeration cycle using a thermoelectric expansion valve, Figure 3 is a system diagram showing a refrigeration cycle using a thermoelectric expansion valve, and Figure 4 is the exhaust gas precooler and exhaust gas dryer in Figure 1. 5 is a perspective view showing part A in FIG. 4, FIG. 6 is a system diagram showing an embodiment of the gaseous waste treatment apparatus according to the present invention, and FIG. 7 is a diagram showing part A in FIG. 6. Pre-cooling/
It is a sectional view showing a dehumidifier. 1... Main condenser 2... Steam air extractor 3... Recombiner 4... Condenser 5... Exhaust gas dryer 6... Exhaust gas precooler 7... Activated carbon Adsorption tower 8... Stack 1o... Refrigerator 11... Compressor 12... Condenser 21... Container 22... Tube 23... Fin 24... Cooling section 25 ... Air population 26 ... Baffle plate 27 ... Air outlet 28 ... Refrigerant inlet 29 ... Refrigerant piping (population) 30 ... Distributor 31 ... Collecting pipe 32 ... Refrigerant piping (Outlet) 50...Precooling/dehumidifier 51...Container 52...Precooling section 53...Dehumidifying section 54...Refrigerant pipe 55...Inflow pipe 56-...Outflow pipe 57...・ Drain pipe 14'S-++ 58 ... Drain pipe 59 ... First baffle plate 60 ...
Baffle plate 61 of fs2...Drain receiver 62...Third baffle plate representative patent attorney
To Suyama Sa-
-14- Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 567- Figure T

Claims (2)

[Claims] (1) Radioactive exhaust gas extracted from the main condenser by an air bleeder is led to a recombiner, the temperature is lowered by the condenser, and the radioactive exhaust gas is removed by an activated carbon adsorption tower via a precooler and dryer. What is claimed is: 1. A radioactive gas waste processing apparatus in which the precooler and the dryer are replaced with an integrated precooler/dehumidifier in a radioactive gas waste processing apparatus in which waste gas is discharged into the atmosphere from a stack. (2) The precooling/dehumidifier has a precooling section at the bottom and a dehumidifying section at the top of the vertical container, and the precooling section and the dehumidifying section are separated by baffle plates, and the radioactive exhaust gas is removed from the container. 2. The radioactive gas waste treatment apparatus according to claim 1, wherein the radioactive gas waste treatment apparatus is configured to flow through a channel such that the flow flows in from below and flows out from above.