JPS61280336A - Ventilating and air-conditioning facility - Google Patents

Abstract

PURPOSE:To permit to reduce the amount of exposure of operators in a central control chamber upon the trouble of atomic power plant by a method wherein air, whose volume is corresponding to removed carbon dioxide, is taken into the chamber in order to keep an atmospheric pressure without increasing the concentration of carbon dioxide. CONSTITUTION:Air, recirculated by emergency recirculating fans 14a, 14b and fans 3a, 3b upon the trouble of the plant, passes through a carbon dioxide removing device 20. In this case, carbon dioxide in the air is removed. Particulate suspended radioactive materials and soluble radioactive materials, remaining in the air taken into the central control chamber 2, are also removed in this case. In case the atmospheric pressure of ventilated and air-conditioned system is reduced due to the removal of carbon dioxide, isolating dampers 13a, 13b are opened and air, whose volume is corresponding to the amount of removed carbon dioxide, is taken into the chamber. Accordingly, small amount of air, taken into the central control chamber 2, may be sufficient for ventilation and the amount of exposure of the operators in the central control chamber may be reduced remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to ventilation air conditioning equipment for removing carbon dioxide generated indoors.

[Technical background of the invention and its problems]

When people work indoors, the Industrial Safety and Health Act and Office Hygiene Standards Regulations stipulate that the carbon dioxide concentration must be below 0.5 VO 1%. If there are openings or openings that do not provide adequate ventilation, a ventilation air conditioning system is required.

Normally, ventilation and air conditioning equipment can provide sufficient ventilation, but under certain conditions, it may be possible to provide only the minimum amount of ventilation that meets the above regulations.

A specific case is ventilation in nuclear power plant central control room ventilation and air conditioning systems during nuclear power plant accidents.

Regarding the ventilation and air conditioning equipment in the nuclear power plant central control room,
A conventional example is shown in FIG. Here, FIG. 7 shows a schematic diagram of a conventional ventilation air conditioner. In FIG. 7, a central control room 2 is installed within a reactor building 1. This central control room 2
Normally, air is supplied to the air conditioner 5 by sucking outside air from outside the reactor building 1 through the air supply looper 4 using the blowers 3a and 3b.
a, 5b and the air duct 6.

Exhaust air from the central control room 2 is passed through an exhaust pipe 10 to an exhaust fan 7.
The air inside the control room is sucked through a and 7b, and the exhaust looper 8
Let's do it from In addition, a part of the exhaust gas is transferred to the emergency recirculation pipe 9
The air then reaches the air conditioners 5a and 5b, and is then returned to the central control room 2.

In one configuration of the ventilation air conditioning during normal operation, if an accident occurs at a nuclear power plant, a large amount of radioactive materials may be released. In this case, the main control room operators are exposed to radiation, which is a problem because the main control room operator is located only a few tens of meters away from the release port for the intermediate substance. Therefore, in case of a nuclear power plant accident, an emergency system is installed in the central control room ventilation and air conditioning system, which can be switched on manually or automatically. The functions of the ventilation air conditioning system at this time include isolation dampers lla, llb, 12a, 12b provided in the blower duct 6, exhaust pipe 10, etc. in order to isolate the central control room 2 from the outside air.
13a.

13b is closed. The air in the central control room is sucked in by emergency recirculation blowers 14a and 14b, and passed through isolation dampers 15a and l+ to a filter (activated carbon filter, etc.) 1.
6, after the air pollution (cigarette smoke etc.) is removed,
Temperature and humidity are controlled by air conditioners 5a, 5b via isolation dampers 17a, 17b and pipe line 9, and air blower 3a.

3b brings them back into the central control room.

However, as mentioned above, if the indoor carbon dioxide concentration is reduced to 0.5
Since it is necessary to keep the VO below 1%, outside air must be brought in appropriately. Next, the operating state in the outside air intake mode at the time of an accident is shown. Distance from the state at the time of the aforementioned accident +i;i
Open the dampers 13a and 13b and turn on the emergency recirculation blower 14.
Outside air is sucked in from the air supply looper 4 by the air supply loopers 4a and 14b, passed through the filter 16, and then supplied to the central control room 2 by the blowers 3a and 3b via the air conditioners 5a and 5b. On the other hand, the air in the central control room 2 is released from the exhaust looper 8 by the amount of outside air taken in by opening the isolation dampers 12a and 12b and by the exhaust fans 7a and 7b. A portion of the exhaust air is sucked into the emergency recirculation blowers 14a, 14b or the blowers 3a, 3bl and recirculated.

Since the filter 16 removes radioactive substances and radioactive iodine floating in the form of particles, the exposure of operators in the central control room 2 to radiation is reduced. However, the radioactive rare gas is sent to the central control room because it does not require 2 filters (1.00% of the radioactive noble gases).
Most of the iodine is around 0%, and the remaining 10% is sent to the central control room 2 (-), where there is a risk that central control room operators may be exposed to radiation.

In order to limit the amount of radioactive material taken in, it is possible to reduce the amount of air supply, but it is necessary to supply at least as much air as possible to comply with the regulations for the working environment as described above.

This air supply amount is mainly determined by the carbon dioxide concentration,
---゛# However, there was a risk that the operator would be exposed to the amount of air supplied.

[Purpose of the invention]

The present invention has been made in view of the above, and is capable of reliably lowering the carbon dioxide concentration in the central control room, reducing the amount of air supplied to the central control room, and reducing the amount of radiation exposure for operators. The purpose is to provide ventilation and air conditioning equipment that can

[Summary of the Invention] In addition to air supply and exhaust, the ventilation air conditioning equipment of the present invention sucks indoor air with a proa, passes it through a carbon dioxide removal device that forcibly adsorbs carbon dioxide in the air, and then removes the remaining air. It is characterized by a circulation pipe that returns air to the room.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 6. Here, FIG. 1 (2) An embodiment of the present invention: A schematic diagram of a ventilation air conditioning system according to 2 is shown.The same parts as in FIG. , the ventilation air conditioning equipment includes an exhaust pipe 10 that exhausts air from the central control room 2 and a blower pipe 6 that supplies air to the central control room 2.
A carbon dioxide removal device 20 is installed in the emergency recirculation pipe 9 that connects the In the above configuration,
In the case of an operating mode of the ventilation air conditioning system in which the central control room 2 is isolated in the event of an accident, the air recirculated by the emergency recirculation blowers 14 a , 14 b and the blowers 3 a , 3 b passes through the carbon dioxide removal device 20 . At this time, carbon dioxide in the air is removed. In addition, particulate floating radioactive substances and water-soluble radioactive substances remaining in the air taken into the central control room 2 are also removed.

If the atmospheric pressure in the ventilation air conditioning system decreases due to the removal of carbon dioxide, open the isolation dampers 13a and 13b,
Removes carbon dioxide and brings in air.

Next, the carbon dioxide removal device according to one embodiment of the present invention was installed in a second
This will be explained with reference to FIGS. Here, Fig. 2(a)
2 shows a schematic diagram of a first embodiment of a carbon dioxide removal device according to an embodiment of the present invention, and FIG. 2(b) shows a plan view of the bubbling device shown in FIG. 2(a).

In FIG. 2, the interior of the carbon dioxide removal device 2o has two phases: a liquid phase portion and a gas phase portion. The gas from which carbon dioxide is to be removed is sent into the removal tank 22 through the blast pipe 21 which has an opening in the liquid phase, and a large number of small holes shown in FIG. 2(b) attached to the open end of the blast pipe 21 are The bubbles become small in diameter in the opened bubbling device 23, carbon dioxide is removed in the liquid phase, and then sent out from the gas phase through the exhaust pipe 24.

The liquid in the liquid phase dissolves carbon dioxide or adsorbs it through a chemical reaction.

As this liquid, first of all water can be used.

Carbon dioxide is about 90% in 100ml of water at 20℃ and 1 atm.
m1 melts. In addition, a part of it is combined with water in the following reaction.

co2+l12o-xn2co3 1-(,;'-1
-HCO8- (1) Number of people in main control room 2 is 20, 1
Reduce carbon dioxide emissions per person to 0.02 m'/h/
For humans, approximately 0.4 rd' of water becomes a carbon dioxide saturated aqueous solution per hour.

Therefore, it is sufficient to replace the water in the removal tank 22 at a pace of 0.4 m'/h. For this purpose, the removal tank 22 is provided with a water pipe 25 and a drain pipe 26 through which makeup water can be sent.

In order to increase the carbon dioxide removal ability, an aqueous solution of a substance that combines with carbon dioxide may be used instead of water.

The substances used may be cyclic groups or basic oxides. Below, examples of two substances are shown.

1. Lime Ca(OH)2+C02−jcacOB↓MoH,O(2
)2, Sodium hydroxide 2NaOH+Co2-ΔNa 200B +H20(3
)3, Barium hydroxide Ba(OH)2 + CO3− □BaCO3+H2
0(4)4, Calcium oxide CaO+ CO2-'= CaCO5(5)5, Magnesium oxide MgO+ Co, -1MgC0s (
6) Here, FIG. 3 shows a schematic diagram of a second embodiment of a carbon dioxide removal device (using a dibasic aqueous solution) according to an embodiment of the present invention. The same parts as in a) are given the same reference numerals, and the explanation of the structure is omitted. In FIG. A chemical liquid tank 33 is installed to store an aqueous solution made from the chemical to be sent and the water sent from the water injection pipe 32.In addition, in the embodiment, the chemical liquid tank is deleted and the role of the chemical liquid tank is replaced by the carbon dioxide removal tank. It's okay to lose.

Furthermore, in order to improve the carbon dioxide removal effect when using water or an aqueous solution for the liquid phase of the carbon dioxide removal tank,
A carbon dioxide removal device as shown in FIG. 4 may also be used.

In FIG. 4, the same parts as those in FIG. In this example,
A stirrer 34 is provided below the removal tank 22, and this stirrer 34 is driven by a stirrer drive device 35 provided below the removal tank 22. With the above configuration, the effect of removing carbon dioxide can be further improved.

Furthermore, the device shown in FIG. 5 may be used as the carbon dioxide removal device. In FIG. 5, a freezing liquid feed pipe 4 through which freezing liquid (liquid oxygen, liquid nitrogen, etc.) flows into a removal tank 40.
1 is connected thereto, and a refrigerant outlet pipe 42 for discharging this refrigerant is also connected.

Further, the gas from which carbon dioxide is to be removed is led through the blast pipe 43, liquefies the carbon dioxide, and discharges it through the drain pipe 44. The gas from which carbon dioxide has been removed is guided out of the removal tank 40 through an exhaust pipe 45. The above configuration (-Therefore, similar to other embodiments) dicarbon dioxide can be removed efficiently.Next, the sixth
A schematic diagram of ventilation air conditioning equipment according to another embodiment of the present invention is shown with reference to the drawings.

Note that the same parts as in FIG. 7 are given the same reference numerals, and the explanation of the structure will be omitted. In FIG. 6, the air inside the central control room is sent by a blower 50 through a blow pipe 51 to a carbon dioxide removal device 52, and after carbon dioxide is removed, the air is returned to the central control room. ing. At this time,
Ventilation and air conditioning systems may be activated to adjust indoor temperature and humidity, but it is preferable to use isolation mode.

Moreover, when the carbon dioxide removal device is made independent from the ventilation air conditioning system, the removal device may be placed indoors.

With the above configuration, effects similar to those of the embodiment of the present invention can be obtained.

〔Effect of the invention〕

If the indoor volume is increased to 4,000 vol., it will take about 50 hours to reach the specified 0.5 vol. unless carbon dioxide is removed.
% concentration, requiring replacement of indoor air. So 4000n for 50 hours? air intake is required. On the other hand, according to the configuration of the present invention, the carbon dioxide concentration does not increase, but increases by the volume of carbon dioxide removed to maintain atmospheric pressure, that is, 0.4 m? /h (for example)
All you need to do is import it. The amount of oxygen consumed is about the same as the amount of carbon dioxide generated, so 0.5 vol% of oxygen is consumed in 50 hours. Since air contains 20% oxygen, it can be ignored.

Therefore, in the event of a nuclear power plant accident, the amount of air taken into the central control room can be reduced to about 1/200, making it possible to significantly reduce the amount of radiation exposure of central control room operators.

Furthermore, when using a water tank, it also has the effect of removing airborne radioactive particles and water-soluble radioactive substances, which can contribute to reducing radiation exposure.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a ventilation air conditioning system showing one embodiment of the present invention, FIG. 2(a) is a schematic diagram showing a first embodiment of the carbon dioxide removal device shown in FIG. Figure (bl is Figure 2 (
Plan view of the bubbling device shown in a), Figures 3 to 5
Each figure shows the second part of the carbon dioxide removal device shown in Figure 1.
FIG. 6 is a schematic diagram showing a ventilation air conditioning system according to another embodiment of the present invention, and FIG. 7 is a schematic diagram showing a conventional ventilation air conditioning system. 1... Reactor building 2... Central control room 3a,
3b...Blower 20...Carbon dioxide removal device 21...Blow pipe 22...Removal tank 23...Bubbling device 24...Exhaust pipe 25.
...Water pipe 26...Drainage pipe agent Patent attorney Noriyuki Chika (and 1 other person) (a)
tb-Figure 2 Figure 3 Figure 4 Figure 5

Claims (3)

[Claims] (1) In ventilation air conditioning equipment that ventilates the air in a central control room installed in a reactor building, the air in the central control room is drawn out by an exhaust fan, and this air is passed through a pipe downstream of the exhaust fan. A ventilation air conditioning system characterized in that the carbon dioxide is passed through a carbon dioxide removal device provided to absorb the carbon dioxide and then sent back into the central control room. (2) The carbon dioxide removal device includes a removal tank that holds a liquid that absorbs carbon dioxide, a blow pipe that blows air from the central control room into the removal tank, and a carbon dioxide removal device that is provided at the tip of the blow pipe. A bubbling device with a large number of holes formed therein, an exhaust pipe for discharging the air from which carbon dioxide has been removed to the outside of the removal tank, a water pipe for injecting the liquid that absorbs the carbon dioxide into the removal tank, and a The ventilation air conditioning equipment according to claim 1, comprising a discharge pipe for discharging the carbon-absorbing liquid to the outside of the removal tank. (3) The liquid that absorbs carbon dioxide is formed by mixing at least one of coal, sodium hydroxide, barium hydroxide, barium oxide, and magnesium oxide. Ventilation and air conditioning equipment.