JP2014065620A - Ozone feeding system and effluent treatment system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ozone feeding system capable of executing, in a high efficiency and in a stable manner, an intermittent feed of a high-concentration ozone gas and an effluent treatment system using the same.SOLUTION: In an ozone feeding system including an ozone generator 2 for generating an ozonated oxygen gas by inducing a discharge within a raw ingredient gas including nitrogen and an adsorption/desorption device (adsorption/desorption column 3) for adsorbing or desorbing ozone onto or from an adsorbent depending on temperatures and alternately executing a first mode of cooling the adsorption/desorption device at or below a first temperature so as to induce the adsorption of ozone within the ozonated oxygen gas onto the adsorbent and a second mode of elevating the temperature of the adsorption/desorption device to a level higher than the first temperature so as to output a gas including ozone at a concentration higher than that of the ozonated oxygen gas generated by the ozone generator 2, a nitrogen oxide removal device (NOtrap 4) is configured between the ozone generator 2 and the adsorption/desorption device.

Description

  The present invention relates to an ozone supply system that supplies ozone generated using discharge at a high concentration, and a wastewater treatment system that uses the supplied ozone.

  An activated sludge treatment method using microorganisms is widely known as a method for treating wastewater containing organic matter, but a large amount of excess sludge is generated in the treatment process. Excess sludge is mainly disposed of by incineration, but the problem is that it requires enormous energy and cost. Therefore, volume reduction of the excess sludge itself is eagerly desired, and a sludge volume reduction process using ozone is attracting attention as one of the methods.

In this process, part of the treated water containing surplus sludge that has been aerobically treated with activated sludge in the aeration tank is drawn out to the ozone treatment unit, and ozone is brought into contact with the drawn sludge. And the treated water which contacted ozone is returned to an aeration tank again, and generation | occurrence | production of excess sludge is suppressed by carrying out an aerobic process. At this time, a wastewater treatment method is disclosed in which the cell membrane of the activated sludge cells is efficiently destroyed and pulverized by maintaining the ozone concentration in the treated water in a high range of 120 g / Nm ³ or more (for example, , See Patent Document 1).

Patent Document 1 discloses that by increasing the ozone concentration, the organic components of the bacterial cells are decomposed by ozone to be converted into BOD (Biochemical Oxygen Demand) components that are easily bio-utilized. It is also described that efficiency can be improved. Furthermore, it is described that an effect is produced not only in continuous ozone supply but also in intermittent ozone supply. However, if high-concentration ozone is continuously generated, the load on the ozone treatment unit increases, and the cost required for the ozone treatment becomes enormous. For example, Patent Document 1 also describes that it is difficult to stably obtain a high concentration of ozone, and an ozone concentration of 400 g / Nm ³ is a practical upper limit.

  On the other hand, an intermittent ozone supply device using a selective adsorption action of ozone of silica gel as an adsorbent is disclosed (for example, see Patent Document 2). In this intermittent ozone supply device, the ozonized oxygen gas generated in the ozone generator is introduced into the adsorption / desorption tower, and only the ozone gas is adsorbed by the adsorbent. The high-concentration ozone temporarily concentrated and stored in the adsorption / desorption tower is desorbed from the adsorbent as necessary, and is supplied to the object to be processed through the ejector. That is, it is conceivable to intermittently supply high-concentration ozone by using an adsorption / desorption tower.

JP 2001-191097 A (paragraphs 0016-0017, FIGS. 1-4, paragraph 0062) JP 59-193192 A (page 3, upper right column to lower right column, FIG. 4)

  However, in a general ozone generator using oxygen gas as a raw material, a method of adding a predetermined nitrogen gas to the oxygen gas as the raw material gas is employed. This is a measure for avoiding the ozone zero phenomenon (a rapid decrease in ozone generation efficiency that occurs when high-purity oxygen gas is used as a raw material gas), which has become a hot topic in recent years. In the generator, it is an indispensable matter. Therefore, the output ozonized oxygen gas is accompanied by nitrogen oxides generated due to the dissociation of the added nitrogen in the discharge field, and the adsorbent used in the adsorption / desorption tower includes nitrogen in addition to ozone. At the same time, the oxide is also concentrated by adsorption. Therefore, poisoning and deterioration of the adsorbent occur, and there is a concern about deterioration of adsorption capacity over time and corrosion deterioration of the adsorption / desorption tower.

  Further, the nitrogen oxide easily reacts with a minute amount of water to generate nitric acid, which inevitably causes corrosion of the gas contact member and occurrence of metal contamination (hereinafter referred to as metal contamination). Therefore, the adsorption / desorption tower may be clogged when the generated metal contamination is accompanied by the ozonized oxygen gas. That is, it is difficult to stably supply intermittent high-concentration ozonated oxygen gas simply by adding an adsorption / desorption tower.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an ozone supply system that can efficiently and stably perform intermittent supply of high-concentration ozone gas and a wastewater treatment system using the ozone supply system. And

  An ozone supply system according to the present invention includes an ozone generator for generating ozonized oxygen gas by discharging in a source gas, and a source gas supplied to the ozone generator using an oxygen gas containing nitrogen as the source gas. A supply device, an adsorption / desorption device that adsorbs or desorbs ozone to or from the adsorbent according to the temperature, a temperature adjustment device that adjusts the temperature of the adsorption / desorption device, and the adsorption / desorption device is cooled to a first temperature or lower. A first mode in which the ozonized oxygen gas generated by the ozone generator is supplied to the adsorption / desorption device and ozone is adsorbed by the adsorbent; and the adsorption / desorption device has a temperature higher than the first temperature. The second mode in which the temperature is raised to a temperature of 2 or more and the gas containing ozone having a higher concentration than the ozonized oxygen gas generated by the ozone generator is output is alternately executed. A control device for controlling in cooperation with equipment in the system, characterized by comprising a nitrogen oxide removal device provided between the ozone generator and the adsorption-desorption apparatus.

  According to the ozone supply system of the present invention, nitrogen oxides are removed from the ozonized oxygen gas supplied to the adsorption / desorption device, so that ozone can be generated efficiently, and deterioration of the adsorbent is suppressed, and adsorption / desorption is performed. The intermittent supply of high-concentration ozone gas concentrated by the apparatus can be stably performed. Therefore, sludge can be efficiently reduced in the wastewater treatment system using this.

It is a systematic diagram which shows the structure of the ozone supply system concerning Embodiment 1 of this invention. It is a figure which shows the electrode structure of the discharge type ozone generator used for the ozone supply system concerning each embodiment of this invention. It is a figure explaining the relationship between the ozone concentration of ozonized oxygen gas output from a discharge type ozone generator, and raw material gas consumption. It is a figure explaining the relationship between the ozone concentration of the ozonized oxygen gas output from a discharge type ozone generator, and power consumption. It is a figure explaining the relationship between the amount of nitrogen addition to the raw material gas supplied to a discharge type ozone generator, and ozone generation efficiency. It is a figure explaining the relationship between the ozone density | concentration of the ozonized oxygen gas output from a discharge type ozone generator, and the density | concentration of nitrogen oxides. It is a systematic diagram which shows the structure of the waste water treatment system using ozone from the ozone supply system concerning each embodiment of this invention. It is a systematic diagram which shows the structure of the ozone supply system concerning Embodiment 2 of this invention. It is a systematic diagram which shows the structure of the ozone supply system concerning Embodiment 3 of this invention. It is a systematic diagram which shows the structure of the ozone supply system concerning Embodiment 4 of this invention. It is a systematic diagram which shows the structure of the ozone supply system concerning Embodiment 5 of this invention. It is a systematic diagram which shows the structure of the ozone supply system concerning Embodiment 6 of this invention. It is a figure which shows the electrode structure of the discharge type ozone generator used for the ozone supply system concerning Embodiment 6 of this invention.

Embodiment 1 FIG.
FIGS. 1-6 is for demonstrating the ozone supply system concerning Embodiment 1 of this invention, FIG. 1 is a systematic diagram which shows the apparatus structure of an ozone supply system, a control system, a flow system, etc., FIG. These are the cross-sectional schematic diagrams which show the electrode structure of the discharge type ozone generator used for the ozone supply system concerning this Embodiment and each embodiment demonstrated after that. 3 to 6 are for explaining the characteristics of the discharge type ozone generator used in the ozone supply system according to each embodiment, and FIG. 3 shows the ozonized oxygen gas output from the ozone generator. FIG. 4 is a diagram for explaining the relationship between the ozone concentration and the raw material gas consumption, FIG. 4 is a diagram for explaining the relationship between the ozone concentration of the ozonized oxygen gas output from the ozone generator and the power consumption, and FIG. FIG. 6 is a diagram for explaining the relationship between the amount of nitrogen added to the raw material gas to be supplied and the ozone generation efficiency, and FIG. 6 explains the relationship between the ozone concentration of the ozonized oxygen gas output from the ozone generator and the concentration of nitrogen oxides. FIG. FIG. 7 is a system diagram showing a configuration of a wastewater treatment system that is an application example of the ozone supply system according to the present embodiment and the following embodiments.

First, the overall configuration and flow of the ozone supply system 100 will be described.
As shown in FIG. 1, an ozone supply system 100 according to Embodiment 1 of the present invention has an oxygen supply device 1X and a nitrogen supply device 1N, and supplies a raw material gas containing oxygen containing a predetermined amount of nitrogen as a raw material gas. A supply device 1, an ozone generator 2 that generates high-frequency discharge in the raw material gas supplied from the raw material gas supply device 1 to generate ozonized oxygen gas containing ozone at a predetermined concentration, and an output from the ozone generator 2 And an adsorption / desorption tower 3 having an adsorbent that selectively adsorbs ozone in the ozonized oxygen gas, and is provided between the ozone generator 2 and the adsorption / desorption tower 3. A nitrogen oxide removing device (NO _X trap) 4 for removing nitrogen oxide (NO _X ) as a by-product from the ozonized oxygen gas supplied toward the adsorption / desorption tower 3 is provided.

The ozone generator 2 is cooled by the cooling device 200. Further, in the piping system 6, the portion from the output side of the ozone generator 2 to the adsorption / desorption tower 3 is composed of a temperature regulation region 6T4 for the NO _X trap 4 and a temperature regulation region 6T3 for the adsorption / desorption tower 3. It is set in the adjustment area 6T. In at least the temperature control region 6T3, the brine is circulated by the refrigerator 300, and the temperature is controlled to be a predetermined temperature. In the adsorption / desorption tower 3, only ozone gas out of ozonized oxygen gas is selectively adsorbed on silica gel installed therein as an adsorbent. On the other hand, the gas mainly composed of oxygen that has not been adsorbed passes through the adsorption / desorption tower 3 and is recycled through a gas circulation means such as a circulation pump 6C provided between the oxygen supply device 1X and the nitrogen supply device 1N. Recycle pipe 6Lr is provided.

In addition, after the adsorption of the ozone gas is completed, the high-concentration ozone gas that has been adsorbed and concentrated is desorbed by introducing it into the adsorption / desorption tower 3 using the oxygen gas supplied from the oxygen supply device 1X through the purge gas line 6Lp as the purge gas. . At this time, an ozonized oxygen gas having an ozone concentration of 500 to 2000 g / Nm ³ is supplied to the ejector 8 as a desorption gas. In the ejector 8, the desorption gas is sucked by the driving fluid supplied from the driving fluid supply unit 7, and is injected into the treatment system 80 using ozone through the ozone concentration / flow rate control unit 9. In order to perform these operations, each device in the ozone supply system 100 including the devices constituting the piping system 6 such as the valves 6Va to 6Ve (collectively the valve 6V) and the circulation pump 6C is controlled in cooperation. A control device is not provided. In addition, the arrow in a figure has shown the flow direction of gas.

Next, the detailed configuration of the source gas and each device will be described.
The source gas used here is a mixed gas in which nitrogen gas is added to oxygen gas supplied from an oxygen supply device 1X using a liquid oxygen cylinder or VPSA (Vacuum Pressure Swing Adsorption). The purity and flow rate of the oxygen gas are confirmed by the purity meter 11 and the flow rate control device 12, respectively. Generally, the oxygen purity managed by the system is desirably 99% or more in order to suppress impurity diffusion into the system. In the ozone generator, the higher the oxygen purity in the raw material gas, the higher the concentration of ozone. It is a common belief that can be generated. However, if the purity becomes too high in recent years, for example, when a high-purity oxygen gas having a purity of 99% or more is used as the raw material gas, the ozone generation efficiency is drastically reduced, and the output ozone concentration approaches zero. It is known that a unique phenomenon occurs. In order to avoid this phenomenon, in the raw material gas supply apparatus 1, when the oxygen supply apparatus 1X is of a specification that outputs high-purity oxygen, the output of the nitrogen supply apparatus 1N is adjusted using the purity meter 11 and the flow rate control device 12. In addition, a certain proportion of nitrogen gas is contained with respect to oxygen gas.

  On the other hand, when VPSA or the like is used for the oxygen supply device 1X, the oxygen purity itself output from the oxygen supply device 1X is relatively low and sufficient nitrogen gas is already contained. The operation and stop of the nitrogen supply device 1N may be performed as appropriate. Naturally, if the stop time of the nitrogen supply device 1N becomes longer, the consumption of gas and power is suppressed.

  The ozone generator 2 uses a silent discharge type driven by an alternating high voltage. If the electrode structure is a parallel plate type, for example, as shown in FIG. 2, it is formed so as to form a discharge space Sc having a predetermined gap length Ds between two electrodes. Specifically, it includes a ground electrode 20 and a high-voltage electrode 21 that is disposed so as to have a gap length Ds with respect to the ground electrode 20 and that is provided with a dielectric 22 on the discharge space Sc side.

  The gap length Ds of the discharge space Sc is 0.05 mm to 0.4 mm, preferably 0.1 mm to 0.3 mm. When the gap length Ds exceeds 0.4 mm, the generation efficiency of high-concentration ozone is significantly reduced. Since it becomes difficult, it is not preferable. Moreover, in the ozone generator 2, the generation efficiency of ozone gas in the high concentration region decreases as the gas pressure increases. However, if the gap length Ds is configured to be in the above-described range, a significant decrease is suppressed even in a high gas pressure region, and good ozone generation characteristics can be maintained. Therefore, the operating gas pressure range of the ozone generator 2 in the present embodiment and the following embodiments is 0.05 MPaG or more and 0.5 MPaG or less (G: gauge pressure), preferably 0.1 MPaG or more and 0.00. It is operated at 3 MPaG or less.

  Needless to say, the electrode portion that forms the discharge of the ozone generator 2 is not limited to the parallel plate electrode structure described above, but can also be applied to a cylindrical tube type ozone generator having a so-called concentric coaxial electrode structure. .

  Next, operations and conditions for intermittently generating high-concentration ozonated oxygen gas using the above-described ozone generator 2 will be described. The ozone supply system 100 according to the present embodiment and each of the following embodiments has two operation modes, an adsorption mode and a desorption mode.

<Adsorption mode>
In the adsorption mode, the valve 6Va and the valve 6Vb are opened, and the valve 6Vc and the valve 6Vd are closed. In synchronization with this operation, the valve 6Ve and the valve 6Vf are closed, and the refrigerator 300 operates. In this mode, the ozonized oxygen gas generated by the ozone generator 2 is introduced into the adsorption / desorption tower 3 via the NO _X trap 4 whose temperature is controlled to be lower than that of the adsorption / desorption tower 3. The adsorption / desorption tower 3 is filled with silica gel as an adsorbent, and due to the selective adsorption of silica gel, only ozone gas in the introduced ozonized oxygen gas is adsorbed, and a non-adsorbing component mainly composed of oxygen gas. The gas is sucked from the adsorption / desorption tower 3 by the circulation pump 6C disposed in the recycle pipe 6Lr and recycled to the raw material gas supply apparatus 1 side. Here, although silica gel is used as the adsorbent, a porous material impregnated with fluorocarbon, activated alumina, zeolite, molecular sieve (synthetic zeolite), or the like may be used.

  Since the entire amount of the non-adsorbed component gas that is recycled is reused as the raw material gas of the ozone generator 2, the flow rate of oxygen gas from the oxygen supply device 1X can be reduced as the mode proceeds. In the purity meter 11 and the flow rate control device 12, the purity and flow rate of the mixed gas of the non-adsorbed component gas and the oxygen gas from the oxygen supply device 1X supplemented as a deficiency with respect to the necessary raw material gas flow rate of the ozone generator 2 are monitored. Therefore, an optimum amount of nitrogen gas is supplied from the nitrogen supply device 1N.

  The adsorption efficiency of ozone in the adsorption / desorption tower 3 is defined by the temperature and pressure of the adsorption part where adsorption / desorption is performed, and the adsorption efficiency is improved as the adsorption part is at a lower temperature and a higher gas pressure. In the present embodiment, the adsorption / desorption tower 3 is set to −40 ° C. or lower, preferably −50 ° C. to −70 ° C. by circulating brine using the refrigerator 300. The gas pressure in the adsorbing portion is generally determined by the operating conditions controlled by the ozone generator 2.

  When the discharge pressure from the ozone generator 2 is low, the pressure in the adsorption / desorption tower 3 is increased by providing a compressor or the like before the adsorption / desorption tower 3 to increase the pressure and adjusting the back pressure by the valve 6Vb. It is also conceivable to control as described above. However, in this case, since the primary side of the compressor has a high gas pressure higher than the atmospheric pressure, and the compressor needs ozone resistance, the compressors that can be used are limited and the cost is increased. It is not preferable to provide the equipment between the ozone generator 2 and the adsorption / desorption tower 3. Accordingly, it is preferable that ozonized oxygen gas having a high gas pressure is directly discharged from the ozone generator 2. In this case, for example, the pressure from the ozone generator 2 to the outlet of the adsorption / desorption tower 3 by adjusting the pressure control valve in the ozone generator 2 and the valve 6Vb or adjusting the valve 6Vb alone, that is, the ozone generator 2 The operating pressure may be controlled.

  Another factor that affects adsorption efficiency is the partial pressure of ozone in ozonated oxygen gas. The amount of adsorption increases as the ozone partial pressure increases. Although the ozone partial pressure can be increased by increasing the generated ozone concentration in the ozone generator 2, if the ozone concentration is increased while the amount of ozone generated is constant, the ozone generation efficiency in the ozone generator 2 is reduced. As a result, power consumption increases. The ozone partial pressure can also be improved by increasing the gas pressure in the adsorption section, but the oxygen partial pressure also increases at the same time, increasing the amount of oxygen adsorbed. It cannot be raised. Therefore, the ozone partial pressure in the present embodiment is defined within a concentration range in which the running cost does not increase even if the concentration is increased in the above gas pressure range.

  FIG. 3 and FIG. 4 show changes in the raw material gas consumption and the power consumption with respect to the ozone concentration in the ozonized oxygen gas to be output in the ozone generator 2 with a constant ozone generation amount. The raw material gas consumption and the power consumption are based on one operating condition of the ozone generator 2 shown in the present embodiment. From both figures, it can be seen that, as the ozone concentration in the ozonized oxygen gas is increased, the power consumption increases, but the raw material gas consumption tends to decrease. That is, when the ozone concentration to be output becomes low, the amount of raw material gas consumption increases although the power consumption is small. On the other hand, when the ozone concentration increases, the amount of raw material gas consumption decreases, but the power consumption increases rapidly.

For example, when the ozone concentration exceeds 300 g / Nm ³ , the consumption of the raw material gas is sufficiently small, but the increase in power consumption becomes extremely significant. In this case, the increase in power consumption is too significant, and the effect of reducing raw material gas consumption is not effective. This is because, in the discharge space Sc in the ozone generator 2, the decomposition effect of the generated ozone gas becomes remarkable due to the collision with the electrons in the plasma and the temperature rise of the discharge space Sc, so that the generation efficiency of the ozone gas is lowered. Due to that. In the ozone generator 2, it is necessary to comprehensively determine the running cost associated with the consumption of raw material gas and electric power, cover the increase in electric power consumption by reducing the raw material gas consumption, and set an operating point with excellent cost performance. There is.

From this point of view, in FIGS. 3 and 4, it is considered most economical to operate the ozone concentration in the vicinity of 250 g / Nm ³ . Even if the concentration is increased, the ozone generator 2 is preferably operated in a concentration range in which an increase in power consumption can be compensated by a reduction in raw material gas consumption, for example, an ozone concentration range of 200 to 300 g / Nm ³ .

In the ozone supply system 100 shown in the present embodiment, when the oxygen supply apparatus 1X is a liquid oxygen cylinder, the oxygen purity is at least 99% or more, so that the nitrogen supply apparatus 1N is operated and an appropriate amount of nitrogen gas is obtained. Must be added to the source gas. In the discharge field, the nitrogen gas is dissociated in the same manner as the oxygen gas, and the generated ozonized oxygen gas is accompanied by nitrogen oxides (NO _x ). Nitric acid interferes with the adsorption of ozone generated due to NO _X, corrode gas contact member in the system, such as to produce a metal contamination, induces such as the ability deterioration, and clogging of the adsorbent.

Therefore, the conditions of nitrogen addition are examined using the relationship between the amount of nitrogen added to the source gas and the ozone generation efficiency shown in FIG. 5 and the relationship between the ozone concentration and the by-product NO _x concentration shown in FIG. To do. Here, the nitrogen addition amount indicates the ratio of the nitrogen gas flow rate to the oxygen gas flow rate. As shown in FIG. 5, in the ozone generator 2, the ozone generation efficiency becomes extremely low as the nitrogen gas addition amount approaches zero, and the ozone generation efficiency can be rapidly recovered by addition of 0.1 vol%. Recognize. The amount of nitrogen gas added that maximizes the ozone generation efficiency is about 1.0 vol%, and the efficiency is maintained up to about 2.0 vol%, but it tends to decrease conversely when it exceeds 3.0 vol%. is there. That is, for the ozone generator 2, it is necessary to adjust the nitrogen gas addition amount to a range of 0.1 to 3.0 vol%, but in order to obtain good ozone generation efficiency, the nitrogen gas addition amount is required. Is preferably adjusted to a range of 0.5 to 2.0 vol%.

Next, the ozone concentration to be output from the ozone generator 2 described above, with respect to the nitrogen amount of the material gas will be considered by-product is NO _X concentration. Even when the ozone concentration is set to 300 g / Nm ³ as the upper limit and the nitrogen gas addition amount is set to the minimum of 0.1 vol%, the NO _x concentration produced as a by-product is about 35 ppm as shown in FIG. Even with this concentration of NO _X , ozone is concentrated at the same time as it is concentrated in the adsorption / desorption tower 3 to 500 to 2000 g / Nm ³ .

Naturally, the concentrated NO _x also reacts with trace moisture in the gas and easily forms nitric acid, similarly to the behavior in the ozone generator 2. Concentrated nitric acid with a high concentration produced by NO _x having a concentration exceeding 100 ppm is adsorbed by the adsorbent in the same manner as ozone, and poisons the so-called adsorbent. Therefore, the selective adsorption property of the adsorbent to ozone is hindered, the ozone adsorption efficiency is lowered, and the adsorbent itself is corroded and deteriorated due to the high concentration.

Further, in the adsorbing / desorbing tower 3 being cooled, NO _X (mostly N ₂ O ₅ ) itself is changed from a gas to a solid, and nitric acid corrodes the adsorbing / desorbing tower 3 containing the adsorbent. Generates metal contamination. These solid substances may cause clogging in the gas flow path in the adsorption / desorption tower 3. Considering these, it is considered that the NO _X concentration in the adsorption / desorption tower 3 needs to be reduced to 100 ppm or less so that the concentrated NO _X does not affect the adsorption capacity in the adsorption / desorption tower 3. .

That is, in the desorption column 3, must be avoided as much as possible concentration of NO _X, in order to avoid the effects described above, it is necessary to limit the concentration of NO _X after concentration to 100ppm or less. When the concentration rate of NO _X in the adsorption / desorption tower 3 is taken into consideration, the NO _X concentration that can be allowed to be generated in the ozone generator 2 is about 40 to 60 ppm. Considering the operating conditions to achieve this concentration from FIG. 6, when the ozone concentration to the upper limit of 300 g / Nm ^3, the conditions for NO _X concentration is below 60 ppm, the amount of added nitrogen to the material gas 0.2vol It can be seen that it must be less than%.

  However, 0.2 vol% is the lower limit of the amount of nitrogen added to maintain ozone generation efficiency, and the condition of the amount of nitrogen added to achieve both avoidance of the effect on adsorption / desorption and ozone generation is a pin of 0.2 vol%. It becomes a point. In other words, in such control that keeps the pinpoint, if it swings upward, it will affect the adsorption / desorption, and if it swings downward, the efficiency will be reduced, so that control accuracy is required and the system configuration becomes difficult. Moreover, even if it can be controlled, it is outside the range (0.5 to 2 vol%) in which good efficiency can be obtained as ozone generation efficiency, and is not a condition for obtaining the maximum efficiency, but also a condition that is highly reliable for adsorption / desorption is not.

Therefore, in the ozone supply system 100 according to the present embodiment, the NO _X trap 4 is installed between the ozone generator 2 and the adsorption / desorption tower 3. Thus, by operating at high efficiency ozone generation capable conditions ozone generator 2, even if concentration of NO _X ozonized oxygen gas output becomes higher, the gas supplied to the desorption tower 3 NO _X concentration is allowable range (60 ppm or less, more preferably 40ppm or less) in made to fit.

Even when the nitrogen supply device 1N is not provided, for example, when VPSA or a relatively low-purity oxygen cylinder is used for the oxygen supply device 1X, the nitrogen content in the oxygen gas is 0.5 vol%. And NO _x exceeding 100 ppm is generated from the ozone generator 2. However, as described above, the output gas of the ozone generator 2 in NO _X trap 4, below 60ppm the NO _X concentration containing, preferably so dropped to 40ppm or less, the gas supplied to the desorption tower 3 The NO _X concentration falls within the allowable range.

  Further, when the ozonized oxygen gas generated by the ozone generator 2 is introduced into the adsorption / desorption tower 3 as it is, a temperature distribution (a high temperature portion on the inlet side) is generated in the adsorbent, and the adsorption efficiency at the gas inlet portion of the adsorption / desorption tower 3. Is estimated to decrease. However, in the present embodiment, a temperature control region 6T4 is provided in the flow portion from the output side of the ozone generator 2 to the adsorption / desorption tower 3, and the temperature of the adsorption / desorption tower 3 is measured using a refrigerator (not shown). It is cooled to a lower temperature than the adjustment region 6T3. For this reason, the temperature of the ozonized oxygen gas has already been cooled below the temperature necessary for adsorption when it is introduced into the adsorption / desorption tower 3. Therefore, high-efficiency adsorption of ozone gas can be realized without the occurrence of a temperature distribution in which the temperature on the inlet side of the adsorption / desorption tower increases and does not decrease to the temperature necessary for adsorption.

  Although the adsorption of ozone continues under the conditions as described above, since the valve 6Vd is always closed during this adsorption mode, naturally, ozone is not supplied to the treatment system 80 using ozone. When the adsorbent breaks through, that is, when the adsorption mode is continued even after the saturated adsorption amount of ozone is exceeded, ozone leaks from the adsorption / desorption tower 3 together with the non-adsorbed component gas. Transition to the desorption mode.

<Desorption mode>
In the desorption mode, the supply of the raw material gas and the ozone generator 2 are stopped, the valves 6Va and 6Vb are closed, and the valves 6Vc and 6Vd are opened. In synchronism with these operations, the refrigerator 300 that controls the temperature of the adsorption / desorption tower 3 also stops its operation. In this state, oxygen gas is supplied from the oxygen supply device 1X through the purge gas line 6Lp to the adsorption / desorption tower 3 as purge gas, and the ejector 8 is supplied with drive fluid from the drive fluid supply unit 7.

Desorption is preferably performed at high temperature and low pressure from the viewpoint of desorption efficiency. Therefore, the operation of the refrigerator 300 for controlling the temperature of the adsorption / desorption tower 3 is stopped, and the pressure of the adsorption / desorption tower 3 is reduced to about 100 Torr by the suction force of the ejector 8. The temperature of the adsorption / desorption tower 3 in the desorption mode is preferably released from the low temperature state during the adsorption by the purge gas and becomes higher than that in the adsorption mode, and more preferably −40 ° C. or higher. As a result, the ozone gas obtained by adsorbing and concentrating the ozone generated by the ozone generator 2 is sucked together with the purge gas as the desorption gas, and becomes an ultrahigh concentration ozone gas of 500 to 2000 g / Nm ³ . Further, the ultra-high concentration ozone gas is mixed with the drive fluid of the ejector 8 and injected into the treatment system 80 using ozone through the ozone concentration / flow rate control unit 9.

  The purge gas flow rate is controlled by the ozone concentration set in the ozone concentration / flow rate control unit 9, and the effective ozone concentration of the ozone gas injected into the treatment system 80 using ozone is controlled. Further, since the driving fluid is a gas having a low density such as oxygen, nitrogen and air, and the fluid to be sucked is a non-condensable gas, the gas flow rate of the gas to be sucked / driving fluid from the viewpoint of improving the efficiency of the ejector 8. The ratio is set to be 0.3 to 0.7. This is because, in general, the pump efficiency of the ejector tends to have a convex shape with the maximum efficiency when the gas flow rate ratio is around 0.4. Further, when the suction gas flow rate is constant, if the gas flow rate ratio is decreased to less than 0.3, the driving fluid flow rate increases and the economic efficiency decreases. On the other hand, when the gas flow rate ratio is increased to 0.7 or more, the mixing property of the sucked gas and the driving fluid is lowered.

In synchronism with these operations, the temperature control region 6T4 including the NO _X trap 4 is also heated, and the valve 6Ve and the valve 6Vf are opened, and the purge gas is supplied from the purge gas supply unit 400 to the NO _X trap 4. The trapped NO _X is discharged to the exhaust NO _X processing unit 401. Since NO _X temperature of the exhaust at of the NO _X trap 4 may if regardless discharged state of the trapped NO _X, there is no problem at the temperature achieved with the introduction of the purge gas. However, in consideration of efficient NO _X discharge, it is desirable that the frozen state inside the NO _X trap 4 can be released, and it is preferable that the temperature be 0 ° C. or higher. Here, the purge gas may be the same as the purge gas of the adsorption / desorption tower 3, that is, oxygen supplied from the oxygen supply device 1X. In addition to oxygen, argon, nitrogen, dry air, and the like may be used.

The exhaust NO _X treatment process acts only during the desorption mode desorption tower 3, and ends at approximately the same time process and transition to adsorption mode. Here, a suction device such as a vacuum pump (not shown) is installed between the NO _X trap 4 and the exhaust NO _X processing unit 401, and the inside of the NO _X trap 4 is reduced to a slightly negative pressure before the desorption process is completed. It is better to exclude impurities. The exhaust NO _X treatment unit 401 shown here represents an acidic exhaust gas or waste water treatment facility, a neutralization treatment facility, a waste filling container, and the like.

  By repeating the adsorption mode and desorption mode described above, that is, by repeating the operation and stop of the ozone generator 2, the ozone generator 2 outputs an ozonated oxygen gas having an ozone concentration that can be operated with high efficiency, and the adsorption / desorption tower Ozonized oxygen gas concentrated from 3 can be intermittently output. That is, the high-concentration ozonated oxygen gas required for the ozone treatment can be injected into the treatment system 80 using ozone stably and stably with high efficiency.

According to this configuration, the ozone generator 2 is handled extremely economically. Further, since the nitrogen oxide in the ozonized oxygen gas introduced into the adsorption / desorption tower 3 is controlled so as not to affect the adsorption capacity regardless of the purity of the oxygen gas as the raw material gas, the adsorption / desorption tower The amount of nitrogen oxide introduced into the system is limited, and the entire system can be operated extremely efficiently and stably. Accordingly, the power consumption of the ozone supply system 100 is greatly suppressed, and 500 to 2000 g / Nm ³ of high-concentration ozone gas can be generated to supply the treatment system 80.

In the form of embodiment and subsequent embodiment, the NO _X trap 4, as an example for easy release of trapped NO _X, it is shown an example of removing NO _X by simply cooling, this It is not limited to. For example, it is needless to say that a basic material that reacts with NO _X or an appropriate adsorbent exhibiting an adsorption characteristic with higher NO _X selectivity than ozone may be used. At this time, if it is possible to use an adsorbent is switched characteristic adsorption / release of the NO _X in the temperature range in which the adsorption / desorption are switched in desorption tower 3 in the NO _X trap 4, a temperature adjustment region 6T4 temperature regulatory region 6T3 Adsorption / release in the NO _X trap 4 can be switched only by being accompanied.

Application Example of Ozone Supply System Next, a configuration of a wastewater treatment system will be shown as an example of a treatment system that uses ozone supplied from the ozone supply system according to the first embodiment of the present invention. As shown in FIG. 7, the wastewater treatment system 80W includes an aeration tank 83 for aerobic treatment of wastewater containing organic matter, and ozonized oxygen gas supplied from the ozone supply system 100 to wastewater extracted from the aeration tank 83. It has an ozone treatment unit 85 for performing ozone treatment by injection, a sedimentation tank 88 for separating sludge from waste water, and a waste ozone treatment unit 87 for treating surplus ozone discharged from the ozone treatment unit 85.

The wastewater containing the organic matter introduced into the aeration tank 13 is subjected to aerobic treatment, and a part of the treated water containing excess aerobic treated sludge is drawn out to the ozone treatment unit 85 by the circulation pump 84a. Here, the amount of surplus sludge generated is 3000 kg / day. When the required ozone amount for sludge is 90 mg / g-sludge, approximately 280 kg / day of ozone gas is required. The ozone supply system 100 shown in Embodiment 1 is connected to the ozone processing unit 85. The ozone generator 2 in the interior generates 200 g / Nm ³ of ozone gas. The ozone gas concentrated by the adsorption / desorption operation and having an ozone concentration increased to 1000 g / Nm ³ is injected into the extracted treated water. The

  In addition, intermittent operation in the ozone supply system 100 was set to 4 cycles per day, with an adsorption of 5.5 hours and a desorption of 0.5 hours as one cycle. The treated water ozone-treated in the ozone treatment unit 85 is returned again to the aeration tank 83, and surplus ozone is discharged from the ozone treatment unit 85 to the exhaust ozone treatment unit 87 as waste ozone. In the aeration tank 83, the treated water is sent to the settling tank 88, and sludge is separated from the treated water. The separated sludge is returned again to the aeration tank 83 via the circulation pump 84b, and the supernatant water is discharged. By this process, excess sludge can be reduced by almost 100%.

  In the wastewater treatment system 80W according to the present embodiment, the ozone injection amount into the object to be treated per unit time during the ozone treatment is extremely high by intensively injecting high-concentration ozone in the ozone treatment unit 85. Therefore, solubilization and mineralization of microorganisms in the sludge are promoted, and the degradability when returned to the aeration tank 83 is enhanced. Further, along with the ultra high concentration of ozone gas, the amount of ozone gas injected into the ozone treatment unit 85 can be reduced, the ozone absorption efficiency in the ozone treatment unit 85 is improved, and the reaction efficiency between the treatment object and ozone is also improved. The

As described above, according to the ozone supply system 100 according to the first embodiment, the ozone generator 2 for generating ozonized oxygen gas by discharging in the source gas, and the oxygen gas containing nitrogen as the source gas As a raw material gas supply device 1 to be supplied to the ozone generator 2, an adsorption / desorption device (adsorption / desorption tower 3) that adsorbs or desorbs ozone to or from an adsorbent according to temperature, and an adsorption / desorption device (adsorption / desorption tower 3). The temperature control device (the refrigerator 300 and the temperature control region 6T3) for controlling the temperature and the adsorption / desorption device (adsorption / desorption tower 3) are cooled to the first temperature (−40 ° C., preferably −50 to −70 ° C.) or lower. In addition, the first mode (adsorption mode) in which the ozonized oxygen gas generated by the ozone generator 2 is supplied to the adsorption / desorption device (adsorption / desorption tower 3) to adsorb ozone to the adsorbent, and the adsorption / desorption device ( Adsorption / desorption tower 3) The temperature is raised to a temperature higher than the second temperature (at least −40 ° C.) or higher, and a gas containing ozone at a higher concentration than the ozonized oxygen gas generated by the ozone generator 2 is output from the adsorption / desorption device 3. Provided between the ozone generator 2 and the adsorption / desorption tower 3, a controller (not shown) that controls the devices in the system in cooperation so as to alternately execute the second mode (desorption mode). And a nitrogen oxide removing device (NO _X trap 4).

Therefore, even if the ozone generator 2 is operated under conditions that enable highly efficient ozone generation (for example, ozone concentration 200 to 300 g / Nm ³ , nitrogen addition amount 0.5 to 2 vol%), the adsorption / desorption device (adsorption / desorption) Since the concentration of nitrogen oxides of the ozonized oxygen gas supplied to the tower 3) falls within an allowable range (40 to 60 ppm or less), ozone can be generated efficiently and deterioration of the adsorbent is suppressed, and the concentrated high concentration The intermittent supply of ozone gas (500 to 2000 g / Nm ³ ) can be performed stably. Therefore, if the ozone supply system 100 is introduced into an ozone treatment apparatus such as the waste water treatment system 80W, high-concentration ozone gas can be efficiently applied to the object to be treated, and power consumption related to ozone treatment can be reduced. That is, excess sludge can be reduced by almost 100% at a low running cost.

Further, the nitrogen oxide removing device (NO _X trap 4) has a characteristic of absorbing or releasing nitrogen oxide according to the temperature, and the temperature control device (the refrigerator 300 and the temperature control region 6T) is an adsorption / desorption device. Since the temperature of the nitrogen oxide removal device (NO _X trap 4) is also adjusted in synchronization with the temperature adjustment of the (desorption / desorption tower 3), NO _X is adsorbed in the adsorption mode, and NO _X is released in the desorption mode. Thus, the nitrogen oxide removing device (NO _X trap 4) can be operated while being regenerated.

The ozonized gas generated by the ozone generator 2 in the adsorption mode has an ozone concentration of 200 to 300 g / Nm ³ and is output from the adsorption / desorption tower 3 (to the ejector 8) in the desorption mode. Is configured to have an ozone concentration of 500 to 2000 g / Nm ³ (operating conditions are set), so that the balance between the raw material gas consumption and the power consumption in the ozone generator 2 is good, and the treatment efficiency by the generated ozone Becomes higher.

  Furthermore, since it comprised so that the nitrogen content in source gas might be 0.5-2 vol%, the ozone generation efficiency in the ozone generator 2 is high.

  At this time, if the oxygen supply device 1X of the VPSA (vacuum pressure swing adsorption method) is used for the raw material gas supply device 1, the necessary nitrogen is contained without adding nitrogen, thereby reducing the running cost. it can. Furthermore, the nitrogen supply device 1N can be omitted.

Embodiment 2. FIG.
An ozone supply system according to the second embodiment of the present invention will be described. The ozone supply system according to the second embodiment has the same basic configuration and operation as those of the first embodiment, but is characterized in that the temperature of the piping through which purge gas passes is increased during desorption. It is. FIG. 8 is a system diagram showing the equipment configuration, control system, flow system, and the like of the ozone supply system according to the second embodiment. In the figure, members that are the same as or correspond to the components of the ozone supply system according to the first embodiment are given the same reference numerals, and descriptions thereof are omitted unless particularly necessary.

  As shown in FIG. 8, in the ozone supply system 100 according to the second embodiment, a heat exchanger 201 that can exchange heat with the purge gas line 6Lp is provided as a cooler for cooling the ozone generator 2. did. Then, A of the pipe connected to the heat exchanger 201 and A of the purge gas line 6Lp, and B of the pipe connected to the heat exchanger 201 and B of the purge gas line 6Lp are connected. Thus, in the adsorption mode, the temperature of the temperature adjustment region 6T is controlled to a low temperature by the refrigerator 300 as in the first embodiment. On the other hand, in the desorption mode, the refrigerator 300 is stopped and the heat exchanger 201 The purge gas can be heated by the heat generated by the ozone generator 2.

Thus, by utilizing the exhaust heat of the ozone generator 2, the temperature of the adsorption / desorption tower 3 at the time of desorption is higher than that at the time of adsorption, preferably −40 ° C. or more, more preferably 0 ° C. or more. It can be easily set to 50 ° C. or lower. At the time of desorption, it is preferable that the temperature of the adsorbent is high, but care must be taken because ozone is thermally decomposed when the temperature is too high. The upper limit of the temperature is desirably 50 ° C. or less as a temperature at which NO _X (N ₂ O ₅ ) can be vaporized without solidification, although there is some thermal decomposition of ozone. In the heat exchanger 201, the medium supplied to the ozone generator 2 side is a liquid such as water, which contributes to cooling of the ozone generator 2. Further, the temperature of the purge gas flowing through the purge gas line 6Lp is raised using the heat released from the ozone generator 2 collected from the ozone generator 2. Therefore, the adsorbent temperature in the desorption mode can be increased, and the desorption efficiency of ozone gas can be improved.

Further, since the temperature of the NO _X trap 4 during NO _X emissions suffices regardless discharged state of the trapped NO _X, there is no problem at the temperature achieved with the introduction of the purge gas. However, in consideration of efficient NO _X discharge, it is desirable that the frozen state inside the NO _X trap 4 can be released, and it is preferable that the temperature be 0 ° C. or higher. When the same gas as the purge gas supplied to the adsorption / desorption tower 3 is used as the purge gas from the purge gas supply unit 400, the purge gas heated by the heat exchanger 201 is used, and the temperature is the same as that of the adsorption / desorption tower 3. If it is set so that NO _x emission becomes smoother.

  As described above, according to the ozone supply system 100 according to the second embodiment, the heat exchanger 201 that recovers the heat generated by the ozone generator 2 is provided, and in the second mode (desorption mode), the absorption is performed. Since the purge gas flowing through the desorption tower 3 is configured to be heated through the heat exchanger 201, the adsorbent temperature at the time of desorption increases, and the desorption efficiency of ozone gas can be improved. Therefore, in addition to high-efficiency utilization of the ozone generator 2, the efficiency of the entire system is improved, and high-concentration ozone gas can be efficiently applied to the object to be processed.

Embodiment 3 FIG.
An ozone supply system according to Embodiment 3 of the present invention will be described. The basic structure and operation of the ozone supply system according to the third embodiment are the same as those of the first embodiment, but a heater is added to the temperature control of the adsorption / desorption tower, and the temperature control is performed by both the refrigerator and the heater. The difference is that you can do it. FIG. 9 is a system diagram showing an equipment configuration, a control system, a flow system, and the like of the ozone supply system according to the third embodiment. In the figure, members that are the same as or correspond to the components of the ozone supply system according to the first embodiment are given the same reference numerals, and descriptions thereof are omitted unless particularly necessary.

  As shown in FIG. 9, in the ozone supply system 100 according to the third embodiment, a heater 301 is added to the temperature control of the temperature adjustment region 6T including the adsorption / desorption tower 3. Further, the purge gas line 6Lp is also placed in the temperature control region 6T. In the ozone supply system 100 according to the third embodiment, in the adsorption mode, the temperature in the temperature adjustment region 6T is controlled to a low temperature by the refrigerator 300 as in the first embodiment. On the other hand, in the desorption mode, the refrigerator 300 is stopped, and the heater 301 is used to heat water and warm brine to raise the temperature of the temperature adjustment region 63T at least from the temperature in the adsorption mode. The temperature is preferably set to -40 ° C or higher, and more preferably set to 0 ° C or higher and 50 ° C or lower.

At the time of desorption, it is preferable that the temperature of the adsorbent is high, but care must be taken because ozone is thermally decomposed when the temperature is too high. The upper limit of the temperature is desirably 50 ° C. or less as a temperature at which NO _X (N ₂ O ₅ ) can be vaporized without solidification, although there is some thermal decomposition of ozone. Since the desorption temperature is increased by the above temperature control, the desorption efficiency in the adsorption / desorption tower 3 is improved. Since the purge gas line 6Lp is also incorporated in the temperature control region 63T, the purge gas introduced into the adsorption / desorption tower 3 reaches the same temperature as the adsorbent before being introduced into the adsorption / desorption tower 3. Therefore, temperature distribution does not occur in the adsorbent, and high-efficiency ozone gas desorption can be realized without disturbing the ozone gas desorption efficiency. Furthermore, since the temperature in the NO _X trap 4 is also raised similarly to the adsorption / desorption tower 3, the NO _X component trapped inside is liquefied or vaporized, so that it can be easily discharged and the next adsorption mode at the start, i.e., it is possible to prevent the residual NO _X is introduced into the desorption tower 3 when the valve 6Va is opened.

  According to this structure, since the temperature at the time of desorption can be raised effectively, the desorption efficiency of ozone gas can be improved. Therefore, in addition to high-efficiency utilization of the ozone generator 2, the efficiency of the entire system is improved, and high-concentration ozone gas can be efficiently applied to the object to be processed.

Embodiment 4 FIG.
An ozone supply system according to Embodiment 4 of the present invention will be described. The ozone supply system according to the fourth embodiment is a partial combination of configurations related to temperature adjustment of the ozone supply systems according to the second and third embodiments, and the exhaust heat of the ozone generator is absorbed and desorbed by the tower. It can be used for temperature control (temperature increase). FIG. 10 is a system diagram showing the equipment configuration, control system, flow system, and the like of the ozone supply system according to the fourth embodiment. In the figure, the same or corresponding members as those of the constituent devices of the ozone supply system according to the second or third embodiment are denoted by the same reference numerals, and the description thereof is omitted unless particularly necessary.

  As shown in FIG. 10, in the ozone supply system 100 according to the fourth embodiment, a heat exchanger 201 capable of exchanging heat with the refrigerant is provided as a cooler for cooling the ozone generator 2. And by connecting A of the pipe connected to the heat exchanger 201 and A of the temperature control region 6T, B of the pipe connected to the heat exchanger 201 and B of the temperature control region 6T, the heat exchanger 201 The temperature of the brine used for temperature adjustment in the temperature adjustment region 6T can be increased. Thereby, in this Embodiment, at the time of adsorption | suction mode, the temperature of the temperature control area | region 6T is controlled to low temperature by the refrigerator 300 similarly to Embodiment 3. FIG. Then, in the desorption mode, the refrigerator 300 is stopped, and the heat generated by the ozone generator 2 by the heat exchanger 201 is used for increasing the temperature using the fluid flowing through the heat exchanger 201 and the temperature control region 6T. .

The temperature of the adsorption / desorption tower 3 at the time of desorption should be higher than at least the temperature in the adsorption mode, and is preferably set to −40 ° C. or higher, more preferably 0 ° C. to 50 ° C. At the time of desorption, it is preferable that the temperature of the adsorbent is high, but care must be taken because ozone is thermally decomposed when the temperature is too high. The upper limit of the temperature is desirably 50 ° C. or less as a temperature at which NO _X (N ₂ O ₅ ) can be vaporized without solidification, although there is some thermal decomposition of ozone. In the heat exchanger 201, the medium supplied to the ozone generator 2 side is a liquid such as water, which contributes to cooling of the ozone generator 2, and the medium supplied to the temperature control region 6T side is a gas such as air. Alternatively, a liquid such as water acts to contribute to the temperature increase of the adsorption / desorption tower 3.

Since the desorption temperature is increased by the above temperature control, the desorption efficiency in the adsorption / desorption tower 3 is improved. Since the purge gas line 6Lp is also incorporated in the temperature control region 6T, the purge gas introduced into the adsorption / desorption tower 3 reaches the same temperature as the adsorbent before being introduced into the adsorption / desorption tower 3. Therefore, temperature distribution does not occur in the adsorbent, and high-efficiency ozone gas desorption can be realized without disturbing the ozone gas desorption efficiency. Furthermore, since the temperature in the NO _X trap 4 is also raised similarly to the adsorption / desorption tower 3, the NO _X component trapped inside is liquefied or vaporized, so that it can be easily discharged and the next adsorption mode at the start, i.e., it is possible to prevent the residual NO _X is introduced into the desorption tower 3 when the valve 6Va is opened.

  As described above, according to the ozone supply system 100 according to the fourth embodiment, the heat exchanger 201 that recovers the heat generated by the ozone generator 2 is provided, and in the second mode (desorption mode), the absorption is performed. Since the brine flowing through the temperature adjustment region 6T for adjusting the temperature of the desorption tower 3 is heated through the heat exchanger 201, the ozone gas desorption efficiency can be improved. Therefore, in addition to high-efficiency utilization of the ozone generator 2, the efficiency of the entire system is improved, and high-concentration ozone gas can be efficiently applied to the object to be processed.

Embodiment 5 FIG.
The ozone supply system concerning Embodiment 5 of this invention is demonstrated. The ozone supply system according to the fifth embodiment has the same basic configuration and operation with respect to generation and concentration (desorption) of ozone as in the first embodiment, except that the ejector drive fluid is circulated. FIG. 11 is a system diagram showing the equipment configuration, control system, flow system, and the like of the ozone supply system according to the fifth embodiment. In the figure, members that are the same as or correspond to the components of the ozone supply system according to the first embodiment are given the same reference numerals, and descriptions thereof are omitted unless particularly necessary.

  As shown in FIG. 11, in the ozone supply system 100 according to the fifth embodiment, in order to circulate the driving fluid that flows to the ejector 8 that sucks the ozonized oxygen gas (desorption gas) concentrated at the time of desorption, the ejector 8 is circulated. A circulation line 8Lr having a circulation pump 8c was provided. Since the driving fluid that flows to the ejector 8 acts only on the suction of the desorption gas, the driving fluid to be used is not only oxygen obtained from the source gas supply device 1 but also gas such as argon, nitrogen or dry air. it can. By circulating the driving fluid, the amount of gas used can be suppressed, so that the dilution rate of the desorbed gas can be reduced and the gas cost for the driving fluid can be reduced. Note that even if nitrogen or air is mixed as a driving fluid with the desorbed high-concentration ozone gas, this mixed gas is not exposed to the discharge field, so that nitrogen oxide is naturally not generated.

  According to this configuration, the amount of gas that dilutes the ozonized gas can be reduced without reducing the flow rate of the driving fluid flowing through the ejector 8, and thus the gas cost in the system can be reduced. Therefore, in addition to high-efficiency utilization of the ozone generator 2, the efficiency of the entire system is improved, and high-concentration ozone gas can be efficiently applied to the object to be processed.

  In addition, the ozone supply system 100 concerning said each Embodiment 1-5 is not restricted to the single form of the example described, respectively, You may comprise a some form, or combining some elements. Moreover, the ozone supply system 100 concerning a single form or a combination is not limited to the wastewater treatment system 80W shown in the application example of the first embodiment, but uses that require large volumes of ozone such as water and sewage treatment and pulp bleaching. Applicable to.

  As described above, by combining the elements shown in the respective embodiments, efficient use of the ozone generator 2, improvement of the adsorption / desorption efficiency in the adsorption / desorption tower 3, or reduction of the driving fluid flow rate of the ejector 8 is realized. Therefore, the efficiency of the entire ozone supply system 100 can be improved, and high-concentration ozone gas can be efficiently applied to the object to be processed.

Embodiment 6 FIG.
An ozone supply system according to Embodiment 6 of the present invention will be described. The basic structure and operation of the ozone supply system according to the sixth embodiment is the same as that of the first embodiment, but is characterized in that no nitrogen supply device is provided in the gas supply device. FIGS. 12 and 13 are for explaining the ozone supply system according to the sixth embodiment. FIG. 12 is a system diagram showing the equipment configuration, control system, flow system, etc. of the ozone supply system. FIG. It is a cross-sectional schematic diagram which shows the electrode structure of the discharge type ozone generator used for the ozone supply system concerning this form. In the figure, members that are the same as or correspond to the components of the ozone supply system according to the first embodiment are given the same reference numerals, and descriptions thereof are omitted unless particularly necessary.

  As shown in FIG. 12, in the ozone supply system 100 according to the sixth embodiment, the source gas supply device 1 is not equipped with a nitrogen supply device for adding nitrogen, and the source gas source is the oxygen supply device 1X. It becomes only.

  When VPSA or a relatively low-purity oxygen cylinder or the like is used for the oxygen supply device 1X, nitrogen is contained in the source gas without adding nitrogen. Basically, this is the same as in the first to fifth embodiments.

  On the other hand, when a liquid oxygen cylinder having a relatively high purity is used for the oxygen supply device 1X, almost no nitrogen oxide is generated in the discharge space Sc of the ozone generator 2. Therefore, the ozonized oxygen gas containing no nitrogen oxide is supplied to the adsorption / desorption tower 3. Therefore, a stable and highly efficient intermittent ozone supply system can be constructed without causing the adsorbent to deteriorate with time in the adsorption / desorption tower 3.

In the present embodiment, in the adsorption mode, the NO _X trap 4 removes a very small amount of nitrogen oxides generated due to impurity nitrogen components contained in the raw material oxygen gas, and is extremely clean ozonated oxygen Contributes to gas generation and cooling of ozonated oxygen gas. Then, in the desorption mode is the degree to which it is necessary to discharge NO _X processing trace amounts, to inhibit mixing of impurities in the system, the oxygen gas purge gas supplied as a source gas from the purge gas supply unit 400 Limited. Therefore, the system can be kept in a clean state with very few impurities.

  Further, the ozone generator 2 used in the ozone supply system 100 according to the sixth embodiment needs to realize high-efficiency high-concentration ozone generation despite the low nitrogen content in the source gas. For this reason, as shown in FIG. 13, the surface of each of the ground electrode and the high voltage electrode on the discharge space Sc side has a low resistance made of an oxide film carrying a metal oxide or noble metal catalyst having a relatively low surface resistivity. The bodies 31 and 32 are formed.

The low resistance bodies 31 and 32 are metal oxides whose surface resistivity is defined as 10 ⁴ to 10 ¹¹ Ω due to the electrical characteristics and catalytic activity of the electrodes. The low resistance body is most preferably disposed on both electrode surfaces, but it is not always necessary to install the low resistance body on both electrode surfaces, and only one of the low resistance bodies 31 and 32 is effective. The low resistance body 32 can be omitted when the surface resistivity of the dielectric 22 is 10 ⁴ to 10 ¹¹ Ω because the surface of the dielectric 22 also serves as the electrical characteristics of the low resistance. Further, although not shown, even if an oxide film carrying a noble metal catalyst is used instead of the low resistance elements 31 and 32, the same effect as described above can be obtained due to the catalytic activity. In FIG. 13, the ozone generator having a parallel plate electrode structure has been described. However, it is needless to say that the present invention can also be applied to a cylindrical tube ozone generator having a concentric coaxial electrode structure.

Needless to say, the seventh embodiment is not limited to only the first embodiment, but is effective when applied to the other embodiments 2 to 5 or a combination thereof. According to this configuration, in the intermittent ozone supply system shown in the first embodiment, high-efficiency ozone generation can be realized without adding nitrogen. Therefore, the adsorption / desorption tower 3 does not cause any harmful effects due to nitrogen oxides. The NO _X trap 4 acts exclusively on cooling the adsorbed gas. Accordingly, a clean ozone supply system 100 with high adsorption efficiency, extremely high efficiency and no metal contamination can be realized, and not only in wastewater treatment, water and sewage treatment and pulp bleaching, but also in the field of electronic devices such as semiconductor and liquid crystal manufacturing processes. The apparatus can also be applied.

  That is, the aeration tank 83 that performs aerobic treatment on wastewater containing organic matter, and a part of the wastewater containing sludge generated in the aeration tank 83 by the aerobic treatment, and the above-described embodiments or A wastewater treatment system 80W comprising an ozone treatment unit 85 that injects a gas containing ozone supplied from an ozone supply system 100 configured by combining some of these elements and returns the gas to the aeration tank 83. If it does, sludge can be reduced effectively.

1: gas supply device, 2: ozone generator, 3: adsorption / desorption tower (adsorption / desorption device), 4: NO _X trap (nitrogen oxide removal device), 6: piping system, 6C: circulation pump (gas circulation means) 6Lp: purge gas line, 6Lr: recycle line, 6T: temperature control region (temperature control device), 80W: wastewater treatment system, 100: ozone supply system, 201: heat exchanger, 300: refrigerator (temperature control device), 301: Heater.

Claims (7)

An ozone generator that discharges in source gas to generate ozonated oxygen gas;
A source gas supply device that supplies oxygen gas containing nitrogen as the source gas to the ozone generator;
An adsorption / desorption device that adsorbs or desorbs ozone to the adsorbent according to the temperature;
A temperature adjusting device for adjusting the temperature of the adsorption / desorption device;
A first mode in which the adsorption / desorption device is cooled to a temperature equal to or lower than a first temperature, ozone gas generated by the ozone generator is supplied to the adsorption / desorption device, and ozone is adsorbed by the adsorbent; A temperature of the adsorption / desorption device is raised to a second temperature higher than the first temperature or higher to output a gas containing ozone having a higher concentration than the ozonized oxygen gas generated by the ozone generator. A control device that controls the devices in the system in cooperation so as to alternately execute the mode of
A nitrogen oxide removing device provided between the ozone generator and the adsorption / desorption device;
An ozone supply system comprising: The nitrogen oxide removing device has a characteristic of absorbing or releasing nitrogen oxide according to temperature,
2. The ozone supply system according to claim 1, wherein the temperature adjusting device also adjusts the temperature of the nitrogen oxide removing device in synchronization with temperature adjustment of the adsorption / desorption device. The ozonized oxygen gas generated by the ozone generator in the first mode has an ozone concentration of 200 to 300 g / Nm ³ ,
^3. The ozone supply system according to claim 1, wherein the gas output from the adsorption / desorption device in the second mode has an ozone concentration of 500 to 2000 g / Nm ³ .   The ozone supply system according to any one of claims 1 to 3, wherein a nitrogen content in the raw material gas is 0.5 to 2 vol%.   The ozone supply system according to claim 4, wherein the source gas supply device is a vacuum pressure swing adsorption type oxygen supply device. A heat exchanger for recovering the heat generated by the ozone generator is provided;
6. The method according to claim 1, wherein in the second mode, at least one of the adsorption / desorption device and the purge gas supplied to the adsorption / desorption device is heated through the heat exchanger. The ozone supply system according to claim 1. An aeration tank for aerobic treatment of wastewater containing organic matter;
A part of the wastewater containing sludge generated in the aeration tank by the aerobic treatment is extracted, and ozone supplied from the ozone supply system according to any one of claims 1 to 6 is extracted to the extracted wastewater. Injecting a gas containing, and returning the ozone treatment unit to the aeration tank;
A wastewater treatment system characterized by comprising:

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