JPS59136118A - Method for switching operation series of dehumidifying tower - Google Patents

Abstract

PURPOSE:To switch and regenerate dehumidifying towers at optimum cycles by integrating the total flow of gas flowing in dehumidifying towers in an equipment wherein two dehumidifying towers are provided in parallel and operated alternatively. CONSTITUTION:In a rare gas holdup equipment etc. using activated carbon, two dehumidifying towers 6 are provided in parallel, and operated and regenerated alternatively. In switching the operation series, the total flow of gas flowing in the dehumidifier 6 is measured with a flowmeter 13 and a calculator 14 while keeping the humidity of gas constant by means of a dehumidifying cooler 5. In this way, the water quantity adsorbed by the dehymidifier 6 is obtained and compared with the water quantity which can be adsorbed by the dehumidifier 6, and the operation series is switched at the specified value. The frequency of regeneration of the dehumidifier 6 is reduced by this method. Since water is not allowed to flow into activated carbon, the high performance of activated carbon is maintained.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention uses a dehumidifying agent as a method for removing moisture as a pretreatment in order to improve the rare gas hold up performance of activated carbon in an activated carbon type rare gas hold up device. This invention relates to the operation of a dehumidification tower, which is equipped with two filled dehumidification towers, and is concerned with an operation method in which switching between operation and regeneration is carried out by determining the total flow rate of gas flowing in.

[Prior art]

Generally, the exhaust gas is cooled to a constant temperature in a dehumidifying cooler to remove moisture before flowing into the dehumidifying tower. The design flow rate of the dehumidification tower is 4O.
Although it is designed to dehumidify exhaust gas for 5 days at a rate of Nm''/hr, the actual flow rate is very small at 4 to 1 ONm''/llr and constantly changes.

The operation of conventional dehumidification towers is manually switched at regular intervals or depending on the dew point temperature provided at the outlet of the dehumidification tower using a central control panel. Therefore, even though the amount of moisture absorbed by the dehumidifier is small because the inflow gas flow rate is small for a certain period of operation, the dehumidifier is switched and regenerated, making the operation cumbersome. The disadvantage was that the operating cost for regeneration was high.

In addition, the method of switching after the dew point of the outlet gas of the dehumidification tower becomes high has the disadvantage that moisture flows into the activated carbon, resulting in a decrease in the performance of the activated carbon, and that systematic switching and regeneration operation of the dehumidification tower cannot be performed.

[Purpose of the invention]

The purpose of the present invention is to keep the humidity of the gas flowing into the dehumidifying tower constant in the dehumidifying cooler, so that the moisture content in the gas is also constant. Since the amount of water adsorbed in the wet tower can be known, the inlet gas flow rate of the dehumidification tower is integrated and this record is used to switch the operation, thereby providing an operation switching method that can be switched at the optimum regeneration cycle of the dehumidification tower. There is a particular thing.

[Summary of the invention]

A feature of the present invention is that by integrating the gas flow rate at the inlet of the dehumidification tower, the operation can be switched to the optimum regeneration cycle of the dehumidification tower. Therefore, the number of times the dehumidification tower is regenerated can be reduced, and the dehumidification tower can be switched and regenerated in a planned manner.

[Embodiments of the invention]

The flow of gaseous waste treatment according to the present invention is shown in FIG. 1 below. Hydrogen and oxygen produced by radiolysis of reactor water are
The leaked air from the main condenser 1 is extracted from the main condenser 1 by the air extractor 2, diluted to below the detonation limit by the driving steam of the air extractor, and subjected to a catalytic reaction in the recombiner 3. Oxygen and hydrogen turn into water vapor. Water vapor is exhaust gas condenser 4V
After being condensed and removed, the exhaust gas from which moisture has been removed in the dehumidifying cooler 5 and the dehumidifying tower 6 is passed through the activated carbon adsorption tower 7 to attenuate the radioactivity and bring the radioactive concentration below the environmental release standards. After confirming that it is present, it is released into the atmosphere through the exhaust stack 8. Next, an embodiment of the present invention will be described in more detail with reference to FIG. As a method for removing moisture as a pretreatment to improve the adsorption performance of radioactive rare gases (X e , K r ) of the activated carbon 9 packed in the activated carbon adsorption tower 7 , exhaust gas is brought to a constant dew point with a dehumidifying cooler 5 . After the exhaust gas has been cooled and moisture has been removed, a dehumidifying tower 6 filled with a dehumidifying agent 10 is installed to dehumidify the exhaust gas to a predetermined dew point or lower, and the exhaust gas enters an activated carbon adsorption tower 7 where it absorbs radioactive rare gases (Xe, Kr). is adsorbed onto activated carbon 9. Furthermore, if the dehumidifying agent 10 adsorbs a predetermined amount of moisture in the exhaust gas that has flowed into the dehumidifying tower 6, the dehumidifying agent 10 will break through and will no longer be able to maintain the dew point below the predetermined dew point. The two dehumidifying towers 6 are operated and regenerated alternately by opening and closing the valves 12 in order to heat and regenerate the dehumidifying agent 10. Further, at the maximum flow rate at startup, two dehumidification towers 6 are operated in parallel for processing. This switching of the operation series is done by keeping the humidity of the gas constant in the dehumidifying cooler 5, and the amount of moisture in the gas is constant. You can know the water content. The amount of water adsorbed by the dehumidification tower is compared with the amount of water that can be adsorbed by the dehumidification tower, and switching operation is performed at a constant value. That is, the method is such that the operation is switched after determining a predetermined total flow rate of incoming gas using the flow meter 13 provided at the entrance of the dehumidification tower 6 and the calculator 14.

According to this embodiment, the operation series can be switched by the optimum regeneration cycle of the desiccant 10.

〔Effect of the invention〕

As described in detail above, according to the present invention, the number of times the dehumidification tower is regenerated is reduced, and switching and regeneration of the dehumidification tower can be operated in a planned manner. Furthermore, since the switch is made before the dew point of the dehumidifying tower outlet gas becomes high, moisture does not flow into the activated carbon, so the high performance of the activated carbon can be maintained.

[Brief explanation of drawings]

FIG. 1 is a flow diagram of the gaseous waste treatment system. 1... Main condenser, 2... Air extractor, 3... Recombiner, 4... Exhaust gas condenser, 5... Dehumidification cooler, 6
... Dehumidification tower -7 ... Activated carbon adsorption tower, 8 ... Exhaust pipe, 9 ... Activated carbon, 10 ... Dehumidification agent, 11 ... Dehumidification tower regenerator, 12 ... Valve, 13...Flow rate needle, 14.
...Arithmetic unit.

Claims (1)

[Claims] 1. In an activated carbon cloth gas hold-up device consisting of a dehumidifying cooler that cools to a constant temperature, a dehumidifying tower filled with a dehumidifying agent, and an activated carbon adsorption tower filled with activated carbon, the total flow rate of gas flowing into the dehumidifying tower is calculated. A method for switching the operation series of a dehumidifying tower, characterized in that the dehumidifying tower is switched and regenerated according to the determined value.