JPH1192107A - Ozone adsorbing and desorbing device and controlling method of desorption density - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ozone adsorbing and desorbing device in which an ozone gas of a specified concn. can be stably desorbed and supplied at a specified flow amt. without storing ozone of high concn. as it is and without using a diluent gas, and to provide a controlling method of the desorption concn. SOLUTION: This device is equipped with an ozone generator 10 to generate ozone from oxygen, an ozone adsorbing device 12 to adsorb the produced ozone to an adsorbent, an ozone discharging line 14 to supply a carrier gas to the ozone adsorbing device to discharge the desorbed ozone with the carrier gas, a temp. controller 18b to control the temp. of the ozone adsorbing device, a pressure controller 18c to control the pressure in the ozone adsorbing device, and an ozone concn. controller 19 to control the ozone concn. In this device, the temp. is increased and/or the pressure is decreased so as to maintain the desorbed ozone in a const. concn. and at a const. flow rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ozone adsorbing / desorbing apparatus, and more particularly, to an ozone adsorbing / desorbing apparatus and a method for controlling the concentration of desorbed ozone.

[0002]

2. Description of the Related Art Ozone, which is safer than conventional chlorine, has been used for bleaching pulp, sterilizing and deodorizing in water treatment, and decomposing organic substances in sewage treatment.
However, the disadvantage of the introduction of ozone is that the initial cost and running cost of oxygen production and ozone production are high. As a technique for solving both of these at once, the present inventors have disclosed in Japanese Patent Application Laid-Open No. Hei 7-144903 ( Title of Invention: "Ozone generation and concentration device").

[0003] As shown in FIG. 8, this apparatus comprises an oxygen generator 1, an ozone generator 2, an ozone concentrator 3, and a reaction tower 4.
The nitrogen in the compressed air is adsorbed by the nitrogen adsorption towers 5a and 5b of the oxygen production machine 1 to produce oxygen, and this oxygen is supplied to the ozone generator 2, where it is ionized to generate ozone. The ozone concentrator 3 comprises two ozone adsorption towers 7a and 7b filled with silica gel or the like, and the generated ozone is introduced into one of them (for example, 7a) to be adsorbed, and the remaining unadsorbed oxygen is passed through a circulation line 8. And is recycled to the ozone generator 2 and reused. In the other adsorption tower (for example, 7b), nitrogen desorbed from the nitrogen adsorption towers 5a and 5b is introduced from the carrier gas line 9, and the adsorbed concentrated ozone is desorbed and sent to the reaction tower 4. With this configuration, the nitrogen adsorption towers 5a and 5b and the ozone adsorption tower 7
By alternately switching a and 7b, adsorption and desorption are alternately performed, and the concentrated ozone is continuously supplied to the reaction tower 4.

However, in the above-described apparatus, the ozone adsorbed by the ozone adsorption towers 7a and 7b is desorbed by the carrier gas (nitrogen) and supplied to the reaction tower 4. When the desorption is completed and the mode is switched to adsorption, the adsorption is performed. There is a problem that nitrogen remaining in the towers 7a and 7b is mixed into the ozone generator 2 through the circulation line 8. That is, when nitrogen is mixed into the ozone generator 2, there is a problem that NO _x is generated together with ozone generation, and this is supplied to the reaction tower 4.

[0005] In order to solve this problem, the present inventors have provided a purge means for flowing the carrier gas in the reaction tower to the reaction tower side when switching from desorption to adsorption in the ozone adsorption tower, and provided the purge means in the adsorption tower. An ozone generation / concentration apparatus has been proposed in which a residual gas containing nitrogen is purged toward the reaction tower with a gas from an ozone generator or an adsorption tower during adsorption (Japanese Patent Application No. Hei 6-220991).
issue).

With this apparatus, gas is purged from the ozone generator or the adsorption tower during the adsorption to the reaction tower side (main component is oxygen), so that nitrogen may be mixed into the ozone generator 2 through the circulation line 8. NO, NO in ozone generator
The occurrence of _X could be solved essentially.

However, in this apparatus, in order to completely discharge nitrogen in the adsorption tower by purging, the purge time needs to be sufficiently long. During this time, the adsorption / desorption process is stopped, so that the operation rate decreases. In the meantime, there is a problem that expensive oxygen is consumed in large quantities. Further, in the above-described apparatus, in the desorption process, the ozone concentration decreases with the passage of time, and there is a problem that ozone gas having a desired concentration cannot be supplied at a stable flow rate.

In order to solve such a problem, the present inventors use a small amount of oxygen necessary for discharging ozone as a carrier gas, desorb ozone with an ozone adsorber, and remove the desorbed ozone together with the carrier gas. A method of controlling an ozone generator that stores the ozone in a tank and supplies a dilution gas to an ozone tank to control the ozone concentration to a desired value has been proposed (Japanese Patent Application Laid-Open No. 9-142808).

According to this method, at the time of desorption, a small amount of carrier gas (oxygen) first releases high-concentration ozone gas, then introduces it into a dilution tank (ozone tank), and dilutes it with a dilution gas to a predetermined concentration. The ozone concentration in the ozone tank can always be kept at a desired concentration. Further, since a small amount of oxygen is used as a carrier gas at the time of desorption, the gas remaining inside the ozone adsorber is the same oxygen as at the time of adsorption, so that a purging step after desorption is not required, and the adsorption step can be started immediately. Therefore, the purge time during which the adsorption / desorption process is stopped becomes zero, and the operation rate of the apparatus can be increased. Further, by reducing the amount of oxygen used as a carrier gas at the time of desorption to a small amount necessary for discharging ozone, a large amount of oxygen consumed during the conventional purge time can be significantly reduced. Since a small amount of oxygen used as a carrier gas is diluted with a diluent gas (nitrogen or dry air) and supplied to the reactor, there is no possibility that the effect of ozone is reduced as in the case of dry air.

[0010]

However, according to the control method disclosed in Japanese Patent Application Laid-Open No. 9-142808, since the ozone gas released at a high concentration is stored in the ozone tank as it is, unstable high-concentration ozone in the tank may be lost. There is a problem that the concentration is easily reduced due to decomposition, and the high concentration ozone accelerates the deterioration of the apparatus and shortens the service life. Further, in this method, since the concentration is diluted to a predetermined concentration with a diluting gas, there is a problem that stable supply cannot be performed when the required concentration is high.

The present invention has been made to solve such a problem. That is, an object of the present invention is to provide an ozone adsorption / desorption apparatus capable of stably desorbing / supplying a constant concentration of ozone gas at a constant flow rate without storing high-concentration ozone as it is and without using a diluent gas, and An object of the present invention is to provide a desorption concentration control method.

[0012]

According to the present invention, an ozone generator for generating ozone from oxygen, an ozone adsorber for adsorbing the generated ozone on an adsorbent, and a carrier gas supplied to the ozone adsorber are provided. An ozone discharge line for discharging the desorbed ozone together with the carrier gas, a temperature controller for controlling the temperature of the ozone adsorber, a pressure controller for controlling the pressure of the ozone adsorber, and an ozone concentration control device for controlling the ozone concentration. , Wherein the temperature and / or pressure is controlled by the ozone concentration control device so that the desorbed ozone has a constant concentration and a constant flow rate.

[0013] Also, there is provided a desorption concentration control method characterized by raising the temperature and / or lowering the pressure so that the desorption ozone has a constant concentration and a constant flow rate. According to a further preferred embodiment, the flow rate of the carrier gas is further controlled so that the desorbed ozone has a constant concentration and a constant flow rate.

According to the method and apparatus of the present invention, by controlling the temperature and / or the pressure, the desorbed ozone is maintained at a constant concentration and a constant flow rate, without storing the high-concentration ozone as it is, and without diluting gas. Ozone gas of a constant concentration can be stably desorbed and supplied at a constant flow rate without using a gas. The temperature and the pressure are preferably controlled to increase the temperature and / or to reduce the pressure, and it is further preferable to control the flow rate of the carrier gas.

As a specific example of the control of the temperature and the pressure at which the desorbed ozone is maintained at a constant concentration and a constant flow rate, a specific temperature is gradually decreased at a constant temperature, only a temperature is gradually increased at a constant pressure, and a temperature is controlled. And simultaneously changing both the pressure and the pressure. Further, as an adjustment example in which these are mixed, furthermore, at a constant temperature, only the pressure is gradually decreased, and the temperature is also increased in the latter half. Only gradually increase the pressure in the second half, keep the temperature at the intermediate temperature, gradually reduce only the pressure,
Finally, the temperature may be increased again. Furthermore,
Before the start of desorption, an operation of slightly lowering the pressure or slightly raising the temperature may be performed to promote desorption.

According to a preferred embodiment of the present invention, there are provided a plurality of ozone adsorbers, an ozone discharge line, a temperature controller and a pressure controller arranged in parallel with each other, and the desorbed ozone in the desorption step is controlled by the ozone concentration control device. Temperature and / or temperature of each ozone adsorber so that
Alternatively, the ozone adsorbers are successively adsorbed and desorbed with their phases shifted so that the pressure is controlled and ozone at a constant concentration and a constant flow rate is continuously desorbed.

According to the method and the apparatus, ozone having a constant concentration and a constant flow rate can be continuously desorbed.

Preferably, the apparatus further comprises an ozone concentration meter for detecting the concentration of desorbed ozone, and performs feedback control using the detected ozone concentration. With this method and apparatus, even when a desired ozone concentration cannot be obtained at a predetermined pressure and temperature, the desired ozone concentration can be desorbed by controlling the pressure and / or temperature by feedback control.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the drawings, common parts are denoted by the same reference numerals. FIG. 1 is an overall configuration diagram of an ozone adsorption / desorption device according to the present invention. In this figure, the ozone adsorbing / desorbing device desorbs ozone by generating an ozone from oxygen, an ozone adsorber 12 for adsorbing the generated ozone to an adsorbent, and supplying a carrier gas to the ozone adsorber 12. An ozone discharge line 14 for discharging ozone together with a carrier gas, and an ozone adsorber 1
2 includes a temperature controller 18b for controlling the temperature, a pressure controller 18c for controlling the pressure of the ozone adsorber, and an ozone concentration controller 19 for controlling the ozone concentration. Also,
A pump 13 and a switching valve 15a are provided on an adsorption line 11a connecting the outlet of the ozone generator 10 and the inlet of the ozone adsorber 12, and the outlet of the ozone adsorber 12 and the ozone generator 11
A switching valve 15b is provided in the recirculation line 11b connecting the inlets of the valves.

The ozone discharge line 14 includes the ozone adsorber 1
Gas line 14a for supplying a carrier gas to the fuel cell 2
And an ozone gas line 14b for supplying ozone gas from the ozone adsorber 12 to the next step (not shown). The carrier gas line 14a is provided with a switching valve 16a, a flow control valve 17a, and a flow controller 18a. The flow controller 18a detects the flow rate of the carrier gas line and controls the flow control valve 17a. A carrier gas having a required pressure is supplied from the carrier gas supply device 20 to the carrier gas line 14a. Oxygen or dry air is preferred as the carrier gas.

The switching valve 16 is connected to the ozone gas line 14b.
b, a temperature controller 17 for controlling the temperature of the ozone adsorber 12
b, the temperature of the ozone adsorber 12 is detected and
b, a pressure controller 17c for adjusting the pressure of the ozone adsorber 12, and a pressure controller 18 for detecting the pressure of the ozone adsorber 12 and controlling the pressure controller 17c.
and an ozone concentration meter 18d for detecting the concentration of the ozone gas exiting from the ozone adsorber 12 and the ozone concentration meter 18d.

With the above configuration, in the adsorption step,
The switching valves 16a and 16b are closed, the switching valves 15a and 15b are opened, and ozone is generated by the ozone generator 10 using oxygen supplied from an oxygen supply source (not shown), and surplus oxygen is returned to the ozone generator 10. Ozone adsorber 1 while circulating
Ozone can be adsorbed on the adsorbent in the second embodiment.

In FIG. 1, the ozone concentration control device 19 controls the temperature and / or pressure so that the desorbed ozone has a constant concentration and a constant flow rate. The ozone adsorber 12 is filled with silica gel (preferably high-purity silica gel). Ozone is adsorbed by increasing the pressure of the ozone adsorber 12 and decreasing the temperature, and conversely by decreasing the pressure and increasing the temperature. Ozone can be desorbed. Further, the amount of ozone desorbed can be controlled by controlling the pressure and the temperature.

FIG. 2 is a diagram showing an example of controlling the pressure and temperature of the ozone adsorber. Ozone adsorption is performed by increasing the pressure and decreasing the temperature. Therefore, the pressure of the ozone adsorber at the time of completion of adsorption is high, and the temperature is low. As shown in FIG. 2, from this state, the ozone can be desorbed while maintaining the ozone concentration constant by gradually lowering only the pressure at a constant temperature. Furthermore, if the amount of desorption of ozone is insufficient in the latter half only by lowering the pressure, the temperature is further increased in the latter half to completely desorb most of the adsorbed ozone while keeping the ozone concentration constant. I can do it. In addition, when there is one ozone adsorber,
Thereafter, the ozone concentration decreases.

FIG. 3 is a diagram showing an example of controlling the pressure or temperature of the ozone adsorber. FIG. 3 (A) shows a constant temperature and only the pressure is gradually reduced. FIG. 3 (B) shows a constant pressure and only the temperature. Is gradually increased. Thus, the ozone concentration can be kept constant by controlling only one of the pressure and the temperature.

FIG. 4 is a diagram showing an example of controlling the pressure and temperature of the ozone adsorber. FIG. 4A shows a case where only the temperature is gradually increased at a constant pressure and the pressure is also decreased in the latter half.
(B) is to change both temperature and pressure simultaneously,
(C) shows a case where the temperature is maintained at the intermediate temperature, only the pressure is gradually reduced, and finally the temperature is raised again. Thus, by controlling both the pressure and the temperature, the ozone concentration can be kept constant.

Further, before starting the desorption, an operation of slightly lowering the pressure or slightly raising the temperature may be performed to promote the desorption. Also, in the example of FIG.
The concentration of desorbed ozone is detected by d, and feedback control is performed using the detected ozone concentration. With this configuration, even when a desired ozone concentration cannot be obtained at a predetermined pressure and temperature, the desired ozone concentration can be desorbed by controlling the pressure and / or temperature by feedback control.

FIG. 5 is another overall configuration diagram of the ozone adsorbing / desorbing device according to the present invention. In this figure, the ozone adsorbing / desorbing device of the present invention comprises a plurality (three in this figure) of ozone adsorbers 12, an ozone discharge line 14,
It has a temperature controller 18b and a pressure controller 18c.
The ozone concentration control device 19 controls a plurality of devices, controls the temperature and / or pressure of each ozone adsorber so that the desorbed ozone in the desorption step has the same concentration and the same flow rate, and has a constant concentration and a constant value. Each ozone adsorber is sequentially cooled, adsorbed, heated, and desorbed by shifting the phase so that ozone at a flow rate is continuously desorbed.

FIG. 6 is a diagram showing an example of controlling the pressure, temperature and carrier gas flow rate of each adsorption tower in FIG. This example shows a case where two ozone adsorbers 12 (adsorption towers A and B) are used. As shown in FIG. 6, each of the adsorption towers A and B maintains the ozone concentration at a constant temperature by gradually lowering only the pressure, as shown in FIG. This shows a case where the ozone concentration is kept constant by increasing the ozone concentration.
In this example, the carrier gas flow rate is kept constant. With this configuration, the ozone concentration can be kept substantially constant while the flow rate of the carrier gas is flowing through each of the adsorption towers A and B.

Further, as shown in FIG. 6, each ozone adsorber is desorbed with its phase shifted, and a part of the ozone adsorbers is overlapped with each other, so that ozone having a constant concentration and a constant flow rate can be supplied as shown in FIG. It can be continuously desorbed.

FIG. 7 is a diagram showing a cycle time chart of each adsorption tower of FIG. In this example, as in FIG.
The case where three ozone adsorbers 12 (adsorption towers A, B, and C) are used is shown. As shown in this figure, the temperature and / or temperature of each ozone adsorber (adsorption towers A, B, C) is adjusted so that the desorbed ozone in the desorption step has the same concentration and the same flow rate.
Alternatively, the ozone at a constant concentration and a constant flow rate can be continuously desorbed by controlling the pressure and sequentially cooling, adsorbing, raising the temperature, and desorbing each ozone adsorber while shifting the phase.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

[0033]

As described above, the ozone adsorption / desorption apparatus and the desorption concentration control method of the present invention can control the temperature and / or the pressure so that the high-concentration ozone is not stored as it is and the dilution gas can be removed. It has excellent effects such as being able to stably desorb / supply a constant concentration of ozone gas at a constant flow rate without using it.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an ozone adsorption / desorption device according to the present invention.

FIG. 2 is a diagram illustrating a control example of pressure and temperature of an ozone adsorber.

FIG. 3 is a diagram illustrating an example of controlling the pressure or temperature of an ozone adsorber.

FIG. 4 is a diagram showing an example of controlling the pressure and temperature of the ozone adsorber.

FIG. 5 is another overall configuration diagram of the ozone adsorption / desorption device according to the present invention.

FIG. 6 is a diagram showing a control example of pressure, temperature and carrier gas flow rate of each adsorption tower of FIG.

7 is a diagram showing a cycle time chart of each adsorption tower of FIG.

FIG. 8 is a configuration diagram of an ozone generator according to the prior application of the present inventors.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oxygen generator 2 Ozone generator 3 Ozone concentrator 4 Reaction tower 5a, 5b Nitrogen adsorption tower 7a, 7b Ozone adsorption tower 8 Circulation line 9 Carrier gas line 10 Ozone generator 12 Ozone adsorber 14 Ozone discharge line 14a Carrier gas line 14b Ozone gas line 17b Temperature controller 17c Pressure controller 18a Flow controller 18b Temperature controller 18c Pressure controller 18d Ozone concentration meter 19 Ozone concentration controller 20 Carrier gas supply device

Claims (7)

[Claims] 1. An ozone generator for generating ozone from oxygen, an ozone adsorber for adsorbing the generated ozone to an adsorbent, and an ozone for supplying a carrier gas to the ozone adsorber and discharging the desorbed ozone together with the carrier gas. A discharge line, a temperature controller for controlling the temperature of the ozone adsorber, a pressure controller for controlling the pressure of the ozone adsorber, and an ozone concentration controller for controlling the ozone concentration. Controlling the temperature and / or pressure so that the desorbed ozone has a constant concentration and a constant flow rate,
An ozone adsorption / desorption device characterized by the above-mentioned. 2. An ozone adsorber, an ozone discharge line, a temperature controller, and a pressure controller arranged in parallel with each other, and the ozone concentration control device makes the desorbed ozone in the desorption step have the same concentration and the same flow rate. Controlling the temperature and / or pressure of each ozone adsorber and sequentially adsorbing / desorbing each ozone adsorber with a phase shift so as to continuously desorb ozone at a constant concentration and flow rate.
The ozone adsorption / desorption device according to claim 1, wherein: 3. The apparatus according to claim 1, further comprising an ozone concentration meter for detecting the concentration of desorbed ozone, wherein feedback control is performed using the detected ozone concentration.
The ozone adsorbing / desorbing device according to the above. 4. A method for controlling the concentration of desorption, comprising raising the temperature and / or lowering the pressure so that the desorption ozone has a constant concentration and a constant flow rate. 5. The desorption concentration control method according to claim 4, wherein the flow rate of the carrier gas is further controlled so that the desorption ozone has a constant concentration and a constant flow rate. 6. A plurality of ozone adsorbers and an ozone discharge line are arranged in parallel with each other, and the temperature and / or pressure of each ozone adsorber is controlled so that the desorbed ozone in the desorption step has the same concentration and the same flow rate. The desorption concentration control method according to claim 4 or 5, wherein the ozone adsorbers are sequentially desorbed and desorbed with a phase shift, thereby continuously desorbing ozone at a constant concentration and a constant flow rate. . 7. The desorption concentration control method according to claim 4, wherein the concentration of the desorbed ozone is detected and the ozone concentration is feedback-controlled.