JP4027511B2 - Sterilization method of activated carbon - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention, heat input is reduced, is and relates to sterilization how the activated carbon to reliably perform sterilization of activated carbon.
[0002]
[Prior art]
Activated carbon for water treatment is widely used for adsorption and removal of organic substances and odor components in water, and decomposition and removal of oxidants such as residual chlorine and ozone. However, activated carbon for water treatment is prone to various troubles associated with this, as bacteria and other germs easily propagate in the activated carbon layer, even if the activated carbon adsorption capacity still remains as the usage time increases. In some cases. Conventionally, as a method for sterilizing activated carbon that solves these problems, a heat sterilization method, a silver-carrying antibacterial method, a total amount exchange method, and the like have been used. Among these, the heat sterilization method is suitable for sterilizing a large amount of activated carbon. For example, JP-A-6-71249 discloses a means for supplying hot water or steam to an activated carbon packed bed in an activated carbon filtration tower. A tap water purification device and a method of disinfecting various germs propagated in an activated carbon filter tower by heat treatment are disclosed.
[0003]
[Problems to be solved by the invention]
However, even if heat sterilization is performed by a conventional heat sterilization method, it cannot be said that sterilization is necessarily performed reliably. For example, when hot water is caused to flow downward from the top of the activated carbon filtration tower, drift due to air entrapment may occur, and reliable sterilization may not be performed. In addition, when the apparatus is large, even if hot water circulation is performed, if the hot water circulation time is too short, a local temperature drop occurs and reliable sterilization is not performed. In addition, since the entire activated carbon filtration tower is filled with hot water and circulated, there is a problem that the input heat amount increases and the operating cost increases.
[0004]
Accordingly, an object of the present invention is reduced heat input is, and is to provide a sterilizing how activated carbon to reliably sterilize breeding the bacteria in the activated carbon tower.
[0005]
[Means for Solving the Problems]
In such a situation, as a result of intensive studies, the inventor has a structure in which the activated carbon tower is controlled so that the liquid level position is above the water collecting pipe installed in the upper space (free board) of the activated carbon packed bed, When sterilizing activated carbon, if hot water is taken out and circulated from the water collecting pipe, the amount of hot water can be reduced, the amount of input heat can be reduced, and air can be entrained by circulating upward in the activated carbon packed bed. The temperature of hot water in the hot water circulation process is detected by a thermometer provided at the outflow part of the water collecting pipe, control based on the temperature is performed, and the hot water circulation time is longer than a specific time. As a result, it was found that miscellaneous bacteria propagated in the activated carbon tower could be sterilized, and the present invention was completed.
[0006]
That is, in the activated carbon tower in which the water collecting pipe is installed above the activated carbon packed bed and the upper side of the water collecting pipe is controlled to be at the liquid level, hot water is flown upward in the activated carbon packed bed. The present invention provides a method for sterilizing activated carbon characterized by feeding, extracting hot water from the water collecting pipe, and circulating the hot water.
[0007]
Further, the present invention is a water draining step in which a water collecting pipe is installed above the packed bed of activated carbon, and the water in the activated carbon tower controlled so that the upper side of the water collecting pipe is at the liquid level position is drained to the liquid level position, Hot water is sent to the activated carbon packed bed in an upward flow, and the hot water is extracted from the water collecting pipe, so that heat is displayed until the display on the thermometer provided at the outflow portion of the water collecting pipe reaches a predetermined temperature exceeding 80 ° C. A preheating step for circulating water, a hot water circulation step for circulating hot water at a predetermined temperature exceeding 80 ° C. for at least 10 minutes, and a hot water draining step for draining hot water from the activated carbon tower The present invention provides a method for sterilizing activated carbon, comprising: a cooling blow step of filling the activated carbon tower with water and then flowing water until the temperature of the effluent of the activated carbon tower is 40 ° C. or lower. .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, a method for sterilizing activated carbon according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing an example of an apparatus for carrying out the activated carbon sterilization method of the present invention. In the figure, 1 to 9 and 12 are valves, and 10 is an activated carbon tower provided with an activated carbon packed bed 11 for treating raw water with activated carbon, which has various germs as the treatment period elapses. A water collection pipe 20 is installed above the activated carbon packed bed 11 of the activated carbon tower 10. When the activated carbon is sterilized above the water collection pipe 20, the liquid level is controlled so that the liquid pipe is positioned above the water collection pipe 20. An area meter 80 is installed. In addition, a sterilization filter 70 is provided at the top of the activated carbon tower 10 to prevent invasion of germs from the outside. A heater 40 heats the circulating water circulated by operating the pump 30 to a predetermined temperature to produce hot water. Reference numeral 50 denotes a filter for removing contaminants such as dead bodies of bacteria after sterilization. The connecting pipe 13a connecting the water collecting pipe 20 and the inflow pipe 30a of the pump 30 is provided with a thermometer 52 with an alarm device, and the inflow pipe 5a connected to the bottom of the activated carbon tower 10 is provided with a thermometer 51 with an alarm device. Is provided. In addition, in the figure, 60 is a pure water production apparatus that treats activated carbon-treated water to a higher degree, but the post-process is not limited to this, and may be used as drinking water as it is, for example.
[0010]
The installation position of the water collecting pipe 20 is preferably separated from the activated carbon surface layer by an ascending height where the activated carbon expands and rises due to the upward flow of hot water above the activated carbon packed bed 11. Specifically, the interval between the water collecting pipe 20 and the activated carbon packed bed surface is about 300 to 500 mm. Moreover, as a liquid level gauge installation position, a position above the water collection pipe 20 and as close as possible to the water collection pipe 20 is preferable in terms of reducing the amount of hot water, but if the liquid level gauge installation position is too close to the water collection pipe 20 Air may be trapped in the circulating water and drift may occur, preventing reliable sterilization. For this reason, specifically, the liquid level gauge is preferably installed at a position approximately 200 to 300 mm above the water collection pipe 20.
[0011]
Next, the method for sterilizing activated carbon according to the present invention will be described for each step.
(Draining process)
In the state before starting the water draining process, the valve 1, the valve 9 and the valve 7 are open, the other valves are closed, and the pump 30 and the heater 40 are stopped. In this state, the raw water is treated by the activated carbon tower 10 and the treated water is sent to the subsequent pure water production apparatus 60. In order to remove a part of the water in the activated carbon tower 10 from this state, the valve 1, the valve 7 and the valve 9 are closed, the valve 2, the valve 3, the valve 6 and the valve 8 are opened, and the liquid level gauge 80 is operated. Thereby, a part of the water in the activated carbon tower 10 is discharged out of the system by gravity, and the water in the activated carbon tower 10 is filled to the set position of the liquid level gauge 80. Next, the valves 2 and 6 are completely closed.
[0012]
(Preheating process)
The water level is maintained at the position of the liquid level gauge 80 of the activated carbon tower 10, the valve 3, the valve 4, the valve 5, and the valve 8 are opened with the circulation system pipe 13 filled with water, and the pump 30 and the heater 40 is operated, and the circulation system (upward flow with respect to the activated carbon packed bed 11) passes through the pump 30, the heater 40, the filter 50, the valve 4, the valve 5, the activated carbon tower 10, the water collecting pipe 20, the valve 3 and the pump 30 in this order. The hot water is circulated until the display of the thermometer with alarm 52 reaches a predetermined temperature exceeding 80 ° C., for example, 88 ° C. By setting the temperature to be equal to or higher than 80 ° C., the standard of sterilization at a temperature of 80 ° C. or higher at which miscellaneous germs cannot survive, particularly as in the case of pharmaceuticals and pharmaceutical water, can be reliably ensured. Moreover, as the said thermometer, using both the thermometer 51 with an alarm device and the thermometer 52 with an alarm device, and making these displays into a reference | standard, the water collection pipe | tube 20 of the activated carbon tower 10, the pump 30, It is preferable in that the temperature in the circulation system pipe 13 formed by can be surely set to the above temperature or more. Further, in this step, the air in the hot water is deaerated.
[0013]
(Hot water circulation process)
In the preheating step, when the display on the thermometer with alarm 52 is not less than a predetermined temperature exceeding 80 ° C., for example, 88 ° C., the process automatically shifts to the hot water circulation step. That is, the circulation system pipe 13 formed between the pump 30 and the water collecting pipe 20 of the activated carbon tower 10 without performing a special operation such as opening and closing of the valve, that is, the pump 30, the heater 40, the filter 50, the valve 4, the valve 5. In the circulation system passing through the activated carbon tower 10, the water collecting pipe 20, the valve 3 and the pump 30 in order, the display of the thermometer with alarm 52 is not less than a predetermined temperature exceeding 80 ° C., for example at 88 ° C. for at least 10 minutes, preferably The hot water circulation is performed for 15 minutes or more, particularly preferably for 30 minutes. In this step, by setting the hot water temperature and the circulation time within the above ranges, the entire apparatus can be kept at 80 ° C. or higher even in a large-scale equipment, and sterilization can be performed reliably. Moreover, it is preferable that the thermometer used at this process is based on the display of both the thermometer 51 with an alarm device and the thermometer 52 with an alarm device.
[0014]
(Hot water draining process)
After completion of the hot water circulation step, the hot water in the activated carbon tower 10 is drained. That is, the heater 40 is turned off, the operation of the pump 30 and the liquid level gauge 80 is stopped, the valves 4 and 5 are closed, the valves 2, 3 and 6 are opened, and the water in the activated carbon tower 10 is opened. Remove the entire amount by gravity.
[0015]
(Cooling blow process)
The cooling blow process is a process in which water is applied to the activated carbon tower 10 and then cooled by flowing water until the temperature of the outflow water of the activated carbon tower 10 is 40 ° C. or lower. That is, after completion of the hot water draining process, first, the valve 3, the valve 6 and the valve 8 are closed, the valve 1, the valve 5, the valve 12 and the valve 2 are opened, and the pressurized water is passed through the valve 5 to the activated carbon tower 10. The activated carbon tower 10 is filled with water (the liquid level meter 80 and the thermometer 51 with an alarm device are in a released state). The full water state may be confirmed by applying a specified amount with a flow rate and a timer, or may be confirmed by blowing an overflow amount out of the system through the valve 12 and the valve 2. Next, the valve 5, the valve 12 and the valve 2 are closed, the valve 1, the valve 6 and the valve 9 are opened, and the pressure feed water is supplied to the activated carbon tower 10 through the valve 1 and the valve 9 in a downward flow. 5 minutes after the start, the thermometer with alarm 51 is put into an operating state, and blowing is performed until the display is stable and below 40 ° C. After completion of the cooling blow process, the valves 1, 6 and 9 are closed to complete the activated carbon sterilization process of the present invention.
[0016]
According to the activated carbon sterilization method in the embodiment of the present invention, the activated carbon tower 10 is controlled so that the liquid level is above the water collecting pipe 20 installed in the space above the activated carbon packed bed 11 (free board). When the activated carbon is sterilized, hot water is taken out from the water collecting pipe 20 and circulated. Therefore, the amount of hot water may be small and the amount of input heat can be reduced. Moreover, since the hot water is circulated in the upward direction in the activated carbon packed bed 11, it is possible to suppress the drift due to the air bite. Further, the hot water temperature in the hot water circulation step is detected by a thermometer 52 with an alarm provided in the connecting pipe 13a connecting the water collecting pipe 20 and the inflow pipe 30a of the pump 30, and control based on the temperature is performed. In addition, since the hot water circulation time is performed for a specific time or longer, the germs propagated in the activated carbon tower can be surely sterilized. Accordingly, it is possible to reliably ensure the standard of sterilization at a temperature of 80 ° C. or higher, in which miscellaneous bacteria and the like cannot survive, as in the case of a large-scale apparatus, or in the case of pharmaceuticals and pharmaceutical water.
[0017]
The thermometer used in the present invention is not particularly limited, but resistance thermometers such as platinum resistance thermometer, copper resistance thermometer, nickel resistance thermometer, thermistor thermometer, etc. Is preferable. The thermometer is equipped with an alarm device, and preferably has a function of transmitting a signal (alarm) such as valve switching according to a set temperature.
[0018]
In the present invention, the control method for setting the liquid level above the water collecting pipe may be either manual liquid level control or automatic liquid level control, but is preferably automatic control using a liquid level control valve.
[0019]
【Example】
EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, this is merely an example and does not limit the present invention.
Example 1
The activated carbon sterilizer with the following specifications shown in FIG. 1 was used.
(Activated carbon sterilizer)
・ Activated carbon tower: Capacity 4m ³ , sampling flow rate 26m ³ / h (LV13m / h), 15 days operation ・ Activated carbon: 2.0m ³ (trade name “GW32 / 20 Kuraray Coal),
Number of bacteria in the activated carbon layer: 2 × 10 ³ / ml
-Thermometer: Platinum resistance thermometer-Heater: Steam heat exchanger [0020]
(Method of sterilizing activated carbon)
In FIG. 1, the water draining process was performed in an apparatus in which the valve 1, the valve 9 and the valve 7 were open, the other valves were closed, and the pump 30 and the heater 40 were stopped. First, the valve 1, the valve 7, and the valve 9 are closed, the valve 2, the valve 3, the valve 6, and the valve 8 are opened, and the liquid level gauge 80 is operated. It was discharged outside. It took 5 minutes to discharge the water in the activated carbon tower 10 until the water level reached the level gauge. Next, the valves 2 and 6 were completely closed (water draining step). The valve 3, the valve 4 and the valve 5 are opened, the pump 30 and the heater 40 are operated, and hot water is caused to flow upward in the activated carbon packed bed 11, and a circulation system formed between the water collecting pipe 20 and the pump 30, that is, The inside of the circulation system which passed through the pump 30, the heater 40, the valve 4, the valve 5, the activated carbon tower 10, the water collecting pipe 20, the valve 3, and the pump 30 in order was circulated. The hot water was circulated at a circulating flow rate of 10 m ³ / h until the temperature of the thermometer with alarm 52 reached 88 ° C. The circulation time was 60 minutes (preheating step).
[0021]
After completion of the preheating step, hot water was circulated for 30 minutes in the same circulation system as in the preheating step with the alarm thermometer 52 indicating 88 ° C. or higher. This hot water circulation was performed at a flow rate of 10 m ³ / h (hot water circulation process).
[0022]
After completion of the hot water circulation process, the heater 40 is turned off, the operation of the pump 30, the level gauge 80 and the thermometer 51 with alarm is stopped, the valves 4 and 5 are closed, the valves 2, 3 and 6 are closed. The valve 8 was opened, and the water in the activated carbon tower 10 was completely removed by gravity. It took about 20 minutes to drain water (hot water draining process).
[0023]
After the hot water draining process, the valve 3, the valve 6 and the valve 8 are closed, the valve 1, the valve 5, the valve 12 and the valve 2 are opened, and the pressurized water is supplied to the activated carbon tower 10 via the valve 1 and the valve 5. The activated carbon tower 10 was filled with water in about 15 minutes with a countercurrent flow (flow rate 10 m ³ / h). Next, the valve 5, the valve 12 and the valve 2 are closed, the valve 6 and the valve 9 are opened, and the pressurized water is supplied to the activated carbon tower 10 through the valve 1 and the valve 9 in a downward flow (flow rate 26 m ³ / h). Then, after 5 minutes from the start of supply, the thermometer 51 with an alarm was activated, and blowing was performed until the display was stably 40 ° C. or lower. The blow time required about 30 minutes (cooling blow process). After the blow, the valve 1, the valve 6 and the valve 9 were closed and this process was completed.
[0024]
After completion of the cooling blow process, the number of bacteria in the activated carbon-treated water was measured and found to be 0 / ml.
[0025]
【The invention's effect】
According to the method for sterilizing activated carbon of the present invention, the activated carbon tower is structured so that the upper side of the water collecting pipe installed in the space above the activated carbon packed bed (free board) is at the liquid level, and the activated carbon is sterilized. At this time, since hot water is taken out from the water collecting pipe and circulated, the amount of hot water may be small and the input heat amount can be reduced. Moreover, since the hot water is circulated in an upward flow to the activated carbon tower, it is possible to suppress a drift due to air entrapment. In addition, in order to detect the hot water temperature in the hot water circulation step with a thermometer provided at the outflow portion of the water collecting pipe, perform control based on the temperature, and perform the hot water circulation time for a specific time or more, the activated carbon tower It is possible to sterilize the germs that have propagated inside. Therefore, the standard of sterilization at a temperature of 80 ° C. or higher, at which miscellaneous bacteria cannot survive, can be reliably ensured as in the case of a large-scale apparatus or in the case of pharmaceuticals and pharmaceutical water.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an apparatus for explaining a method for sterilizing activated carbon according to the present invention.
[Explanation of symbols]
1 to 9, 12 Valve 10 Activated carbon tower 11 Activated carbon packed bed 13 Circulation system piping (including 13a)
13a Connecting pipe 20 connecting the water collecting pipe and the pump inflow pipe 20 Water collecting pipe 30 Pump 30a Pump inflow pipe 40 Heater 50 Filter 51, 52 Thermometer 60 with alarm device Pure water production device 70 Bactericidal filter 80 Liquid level gauge

Claims (2)

  In the activated carbon tower in which a water collecting pipe is installed above the activated carbon packed bed and is controlled so that the liquid level is above the water collecting pipe, hot water is sent to the activated carbon packed bed in an upward flow, from the water collecting pipe A method for sterilizing activated carbon, characterized in that hot water is extracted and circulated. A drainage step of installing a water collection pipe above the activated carbon packed bed, and draining water of the activated carbon tower controlled so that the upper side of the water collection pipe is at the liquid level position,
By sending hot water in an upward flow to the activated carbon packed bed and extracting hot water from the water collecting pipe, until the display of the thermometer provided in the outflow part of the water collecting pipe reaches a predetermined temperature exceeding 80 ° C. A preheating step for circulating hot water,
A hot water circulation step for performing hot water circulation at a predetermined temperature exceeding 80 ° C. for at least 10 minutes;
A hot water draining step for draining hot water from the activated carbon tower;
A method for sterilizing activated carbon, comprising a step of filling the activated carbon tower with water and then introducing water until the temperature of the effluent of the activated carbon tower reaches 40 ° C. or lower.

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