JP2005246256A - Ozone thermal decomposition apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ozone thermal decomposition apparatus capable of reducing a consumption energy required for the ozone thermal decomposition of ozone-containing gas. <P>SOLUTION: The apparatus is provided with: a thermal exchange part 14; a heating part 15; a packed part 11 which is packed with silica gel 25; a heater 21 which heats the heating part 15 and holds the packed part 11 at a constant temperature; and a communication pipe 18 which is communicated with the packed part 11 and penetrates through the thermal exchange part 14. Therein, the ozone-containing gas derived from the thermal exchange part 14 to the heating part 15 is heated at a constant temperature in the range of 100°C to 350°C by the heater 21, is allowed to pass through the packed part 11 which is held at a constant temperature in the range of 100°C to 350°C, thereby ozone is thermally decomposed and, at the same time, the ozone-containing gas in the thermal exchange part 14 is preheated by ozone-removed gas passing through the communication pipe 18. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ozone pyrolysis apparatus that thermally decomposes ozone in an ozone-containing gas.

  In recent years, ozone-containing gas, that is, ozone gas, is widely used for sterilization of water and sewage, wastewater treatment, sterilization and cleaning of processed foods and medical instruments, deodorization, and the like. Here, ozone gas having a high concentration may have various effects on the living body due to its strong oxidizing power, which may cause visual impairment or cause irritation in the respiratory tract. Therefore, it is necessary to decompose and discharge excess ozone that has not dissolved in water or reacted, into oxygen.

  Thermal decomposition apparatuses are widely used for conventional ozone treatment. As this type of thermal decomposition apparatus, for example, as shown in FIG. 3, a cylindrical ceramic heater 101 in which heater wiring is embedded in ceramic, and a stainless steel material provided so as to surround the outer periphery of the ceramic heater 101 A bottomed cylindrical case body 102 is provided, and a gas injection pipe 103 is inserted into the center portion of the ceramic heater 101 through the case main body 102, and a gas discharge port 104 is provided in the case main body 102. The ozone gas injected from the gas injection pipe 103 passes through an annular space in the center of the ceramic heater 101 and an annular gap formed by the outer periphery of the ceramic heater 101 and the case body 102, and is a gas discharge port. There is known a ceramic heater unit 100 for ozonolysis in which ozone gas is heated to about 500 ° C. by a ceramic heater 101 while being discharged from 104 to thermally decompose ozone (see, for example, Patent Document 1).

  Further, as shown in FIG. 4, a dehumidifying portion 114 is provided in an ozone gas supply path 113 that supplies ozone gas discharged from an ozone contact tank 111 in which treated water is stored to the thermal decomposition apparatus 112, and ozone gas from the ozone gas supply path 113 is provided. There is known an exhaust ozone gas treatment device that decomposes ozone by heating to about 500 ° C. in a heat treatment device 112 and supplies the high-temperature gas after the decomposition to a dehumidifying part 114 in a wet state to regenerate the adsorbent (for example, , See Patent Document 2).

Japanese Patent Laid-Open No. 10-180037 JP 2001-190930 A

  According to the ceramic heater unit for ozone decomposition 100 disclosed in Patent Document 1, ozone gas flows along the surface of the ceramic heater 101 made of ceramic, and corrosion of the heater wiring is prevented without the ozone gas contacting the heater wiring. Durability is improved.

  However, since ozone gas is heated to a high temperature of about 500 ° C. by the ceramic heater 101 and thermally decomposed, there is a concern that a great amount of electric energy is consumed for the heating. Further, heat resistance of peripheral members such as a member that holds the ceramic heater 101 heated to a high temperature of about 500 ° C. is also required.

  Further, according to the exhaust ozone gas treatment device disclosed in Patent Document 2, a dehumidifying portion 114 is provided in the ozone gas supply passage 113 for supplying ozone gas to the thermal decomposition device 112, and the decomposed high-temperature gas discharged from the thermal decomposition device 112 Is supplied to the dehumidifying unit 114 to regenerate the adsorbent, so that the energy consumption required for dehumidifying the ozone gas supplied to the thermal decomposition apparatus 112 in advance and decomposing ozone by the thermal decomposition apparatus 112 can be suppressed. .

  However, since ozone is thermally decomposed by being heated to a high temperature of about 500 ° C. by the thermal decomposition apparatus 112, there is a concern that a large amount of electric energy is required for the thermal decomposition, and heat resistance is also required.

  Here, as a result of diligent research and experiments, the present inventors have thermally decomposed ozone in the presence of silica gel, zeolite, porous glass, porous ceramic or porous metal sintered body, It has been found that the heating temperature can be reduced.

  Accordingly, an object of the present invention made in view of such points is to provide an ozone pyrolysis apparatus that can reduce the heating temperature required for the ozone pyrolysis of an ozone-containing gas and can reduce the consumption energy.

  The invention of the ozone pyrolysis device according to claim 1, which achieves the above object, is an ozone pyrolysis device for thermally decomposing ozone in an ozone-containing gas, and a heat exchange section communicating with an ozone-containing gas inlet, and the heat exchange A heating part communicating with the heating part, a filling part communicating with the heating part and filled with granular silica gel, zeolite, porous glass, porous ceramic or porous metal crystal, and the heating part 100 Heating means for heating to a constant temperature in the range of ℃ to 350 ℃ and holding the filling part at a constant temperature in the range of 100 ℃ to 350 ℃, and one end communicating with the filling part and penetrating through the heat exchange part A communication pipe whose end communicates with the ozone-removed gas outlet, and the ozone-containing gas supplied from the ozone-containing gas inlet to the heating unit through the heat exchange unit is heated to 100 ° C. to 35 ° C. by the heating means. Heated to a constant temperature in the range of ° C., the ozone is thermally decomposed by passing through the filling part where the heated ozone-containing gas is held at a constant temperature in the range of 100 ° C. to 350 ° C. The gas is discharged from the ozone-removed gas outlet through the communication pipe, and the ozone-containing gas in the heat exchange section is heated by the ozone-removed gas flowing through the communication pipe.

  According to a second aspect of the present invention, in the ozone pyrolysis apparatus according to the first aspect of the present invention, the heat exchange section is partitioned into a labyrinth and has a baffle plate coupled to the communication pipe.

  According to a third aspect of the present invention, in the ozone pyrolysis apparatus according to the first or second aspect, the filling portion is provided in a container provided with the ozone-containing gas inlet, and the inside of the container is heated by the filling portion. It is characterized by partitioning into an exchange part and a heating part.

  According to a fourth aspect of the present invention, in the ozone pyrolysis apparatus according to any one of the first to third aspects, the ozone-removed gas outlet is provided in communication with the other end of the communication pipe adjacent to the heat exchange section. The storage tank is arranged.

  According to invention of Claim 1, the ozone containing gas inject | poured into the heat exchange part from the ozone containing gas inlet_port | entrance is pre-heated by the ozone removal completed gas which distribute | circulates a communicating pipe, This pre-heated ozone containing gas is made into a heating part. It is heated to a constant temperature in the range of 100 ° C. to 350 ° C., and the heated ozone-containing gas is filled with granular silica gel, zeolite, porous glass, porous ceramic, or porous metal crystal and is heated to 100 ° C. Because the ozone is thermally decomposed while passing through the filling maintained at a constant temperature in the range of ˜350 ° C., the temperature of about 500 ° C. was required for conventional ozone pyrolysis. Compared to the above, the temperature required for ozone pyrolysis can be set very low, and the energy consumption required for ozone pyrolysis can be greatly reduced.

  According to the second aspect of the present invention, the heat transfer area can be secured by arranging the baffle plate that is coupled to the communication path and divides the heat exchange part into a labyrinth, and the residence time of the ozone-containing gas in the heat exchange part is secured. The ozone-containing gas can be preheated well.

  According to invention of Claim 3, a filling part, a heat exchange part, and a heating part can be formed by the simple structure which partitions the inside of a single container into a heat exchange part and a heating part by a filling part.

  According to the invention of claim 4, by arranging a storage tank for storing the ozone-removed gas adjacent to the heat exchange part, the ozone in the heat exchange part is also obtained by the high temperature ozone-removed gas stored in the storage tank. The contained gas can be preheated.

  Hereinafter, an embodiment of the ozone pyrolysis apparatus will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a cross-sectional view schematically showing an ozone pyrolysis apparatus 1. The ozone pyrolysis apparatus 1 includes a cylindrical cylindrical portion 3 made of a stainless steel material having an anticorrosive property superior to ozone-containing gas, that is, ozone gas, and a cylindrical cylindrical portion 3 that is continuous above and below the cylindrical portion 3. It has the hollow container 2 long in the up-down direction formed by the upper surface part 4 and the bottom surface part 5 which seal each opening. A conduit 6 having an ozone-containing gas inlet 7 communicates with the lower part of the side surface of the cylindrical portion 3. A bottomed cylindrical storage tank 8 is continuously formed below the bottom surface portion 5, and an ozone-removed gas outlet 9 communicates with the side surface of the storage tank 8.

  A bottomed cylindrical filling portion 11 formed by the side portion 12 and the bottom portion 13 is provided in the upper portion of the container 2. The inside of the container 2 is partitioned into a lower heat exchange part 14 and an upper heating part 15 by the filling part 11, and the heat exchange part 14 and the heating part 15 are constituted by the side part 12 of the filling part 11 and the cylindrical part 3 of the container 2. Is formed. That is, the filling part 11, the heat exchange part 14, and the heating part 15 can be formed in the container 2 by a simple configuration in which the inside of the single container 2 is partitioned into the heat exchange part 14 and the heating part 15 by the filling part 11.

  The hollow heat exchange part 14 formed by the cylindrical part 3 and the bottom part 5 of the container 2 and the bottom part 13 of the filling part 11 exchanges ozone gas injected from the ozone-containing gas inlet 7 into the heat exchange part 14. In order to secure the time for staying in the portion 14, it is partitioned in a maze shape by a plurality of baffle plates 17 extending in the horizontal direction.

  A plurality of communication pipes 18 having one end communicating with the filling portion 11 and the other end communicating with the storage tank 8 via the bottom portion 5 are provided between the bottom portion 13 and the bottom surface portion 5 of the filling portion 11. It is provided through. A plurality of communication pipes 18 spanned between the bottom portion 13 and the bottom surface portion 5 of the filling portion 11 penetrate the respective baffle plates 17 and are coupled to be able to transfer heat. The baffle plate 17 and the communication pipe 18 are formed of a stainless steel material having excellent corrosion resistance against ozone gas and excellent heat conductivity.

  A heating heater 21 such as an infrared heater serving as a heating means is disposed in a heating unit 15 formed above the filling unit 11. Reference numeral 22 denotes a terminal box of the heater 21 for heating. Further, a thermocouple 23 is provided as a temperature detecting means for detecting the temperature of the filling portion 11. In the thermocouple 23, a tip 23 a that penetrates the upper surface portion 4 and serves as a temperature detection portion is set in the filling portion 11.

  Based on temperature detection by the thermocouple 23, the output of the heater 21 is controlled by a control means (not shown) to heat the heating unit 15 to a preset temperature and keep the temperature of the filling unit 11 constant. That is, in the present embodiment, the output of the heater 21 is controlled based on temperature detection by the thermocouple 23 to heat the temperature of the heating unit 15 to a constant temperature in the range of 100 ° C. to 350 ° C., and the filling unit 11. Is kept at a constant temperature in the range of 100 ° C to 350 ° C.

  The lower range in the filling part 11 is filled with fine particles having a large number of pores and having a large surface area, for example, silica gel 25 having a diameter of 3 mm to 4 mm.

  As indicated by arrows in FIG. 1, ozone gas is continuously injected from the ozone-containing gas inlet 7 into the lower part of the heat exchange unit 14 formed in the container 2 through the conduit 6. The ozone gas injected into the lower part of the heat exchanging unit 14 is guided along each baffle plate 17 and gently rises in the heat exchanging unit 14 while meandering, and is supplied to the heating unit 15 from the communication path 16.

  The ozone gas supplied to the heating unit 15 is heated to, for example, a range of 100 ° C. to 350 ° C. by the heater 21 for heating. The heated ozone gas is continuously formed in the heating unit 15, passes through the filling unit 11 filled with the silica gel 25, and is sent to the communication pipe 18. At this time, the ozone gas passing through the filling portion 11 is maintained at a constant temperature in the range of 100 ° C. to 350 ° C. by the heater 21 in the presence of the silica gel 25, and the ozone is thermally decomposed into oxygen to become an ozone-removed gas. Then, it is sent to the storage tank 8 through the communication pipe 18, cooled in the storage tank 8, and then released into the atmosphere through the ozone-removed gas outlet 9.

  Here, the high-temperature ozone-removed gas that has been heated and held at 100 ° C. to 350 ° C. and has been subjected to thermal decomposition of ozone through the filling portion 11 circulates in the communication pipe 18 disposed in the heat exchange portion 14. The communication pipe 18 is heated in between, and each baffle plate 17 coupled to the communication pipe 18 is heated. On the other hand, the ozone gas continuously injected from the ozone-containing gas inlet 7 to the lower part of the heat exchanging section 14 is guided along each baffle plate 17 in which a sufficient heat transfer area is secured, and gently rises in the heat exchanging section 14. However, it is heated by the communication pipe 18 and the baffle plate 17. Further, the ozone gas in the heat exchange unit 14 is heated through the bottom surface part 5 by the hot ozone-removed gas that stays in the storage tank 8 disposed adjacent to the heat exchange unit 14.

  In this way, the ozone gas supplied to the filling unit 11 via the heating unit 15 is heated in advance in the heat exchanging unit 14, thereby suppressing the consumption of electrical energy required to heat the ozone gas by the heating heater 21. And efficient ozone pyrolysis.

  Further, in place of the silica gel 25, the filling portion 11 may be filled with a fine zeolite having a large number of pores and a granular zeolite capable of ensuring a large surface area.

  FIG. 2 shows the primary reaction constant indicating the ozonolysis capability in the ozone pyrolysis apparatus 1 configured as described above, the case 1 in which the filling part 11 is filled with silica gel 25, and the case 2 in which the filling part 14 is filled with zeolite. The experimental result acquired with respect to the case 3 of the empty state which does not fill the filling part 11 with a filler is shown.

  Here, the primary reaction rate constant is the natural logarithm of the ratio of the inlet ozone concentration at the ozone containing gas inlet 7 of the ozone gas to be treated and the outlet ozone concentration of the ozone removed gas outlet 9 at the ozone removed gas outlet 9. This is a value divided by the gas residence time from the ozone-removed gas outlet 9 to the ozone-removed gas outlet 9, and is an index used to express a chemical reaction rate that generally proceeds at a rate proportional to the concentration.

  According to FIG. 2, the case 1 in which the packing part 11 is filled with silica gel has a primary reaction rate constant that is 5 times or more that of the case 3 in which the packing part 11 is not filled with a filler. It can be confirmed that the case 2 filled has a primary reaction rate constant that is equal to or higher than that of the case 1 filled with silica gel. Furthermore, it has been confirmed that practical ozone pyrolysis is possible in a temperature range of 100 ° C. to 350 ° C., whereas conventional pyrolysis of ozone requires a high temperature of about 500 ° C.

Further, for example, when the ozone pyrolysis apparatus 1 shown in FIG. 1 heats ozone gas at a temperature of 50 ° C. supplied at a flow rate of ³ Nm ³ / min to 275 ° C. with a heater 21 of 5 kW, the ozone is pyrolyzed. If there is no heat exchanging part 14, about 15 kW of electrical energy is required to raise the ozone gas to 275 ° C., but heat is recovered through the communication pipe 18 and the baffle plate 17 having a heat transfer area of about 10 m ^2. By previously heating the ozone gas, the energy consumed by the heater 21 can be reduced to about one third.

  Therefore, according to the present embodiment, the heating unit 15 heats the ozone gas to a constant temperature in the range of 100 ° C. to 350 ° C., and the heated ozone gas is filled with silica gel or zeolite in the temperature range of 100 ° C. to 350 ° C. Since the ozone is thermally decomposed and heated while passing through the heat-filled filling 11 and passing through the filling portion 11, the ozone heat is higher than that required for the conventional ozone pyrolysis at a temperature of about 500 ° C. The temperature required for the decomposition can be set extremely low, the electric energy required for the ozone pyrolysis can be greatly reduced, and the energy consumption can be reduced. Moreover, durability of the structural member used for the ozonolysis apparatus 1 such as the container 2 is improved as the temperature required for the ozone pyrolysis decreases.

  In particular, a high-temperature ozone-removed gas that has been passed through the filling section 11 and has been subjected to thermal decomposition of ozone is circulated through the communication pipe 18 disposed in the heat exchange section 14, so that the inside of the communication pipe 18 and the heat exchange section 14. The ozone gas flow path is formed into a labyrinth to heat the ozone gas through the baffle plate 17 that secures the residence time of the ozone gas, so that the ozone gas is preheated satisfactorily and is required for heating the ozone gas by the heater 21 for heating. Consumption energy can be suppressed, and efficient thermal decomposition of ozone in the filling unit 11 is performed.

  Further, the ozone pyrolysis apparatus 1 divides the inside of the hollow container 2 into a heat exchanging unit 14 and a heating unit 15 by a filling unit 11 filled with silica gel 25 or zeolite, and a heating heater 21 is provided in the heating unit 15. The arrangement is simple, and the communication pipe 18 is arranged in the heat exchanging section 14, and a reduction in equipment cost can be expected.

  In addition, as a filling material to be filled in the filling 11, a porous glass, a porous ceramic, or a porous metal sintered body is used instead of silica gel or zeolite, and it is practically used in a temperature range of 100 ° C. to 350 ° C. Ozone thermal decomposition is possible.

  These silica gels, zeolites, porous glass, porous ceramics, porous metal sintered bodies, etc. have no toxicity that affects the human body, and are non-toxic industrial wastes when they are replaced after long-term use. This process has very little impact on the environment.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. For example, in the above embodiment, a thermocouple is used as the temperature detecting means, but a thermistor can be used.

It is sectional drawing which shows the outline of the ozone pyrolysis apparatus concerning the 1st Embodiment of this invention. It is comparison explanatory drawing of a primary reaction rate constant. It is explanatory drawing of the conventional waste ozone gas processing apparatus. It is explanatory drawing of the conventional ceramic heater unit for ozonolysis.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ozone pyrolysis apparatus 2 Container 6 Conduit 7 Ozone containing gas inlet 8 Storage tank 9 Ozone-removed gas outlet 11 Filling part 14 Heat exchange part 15 Heating part 16 Communication path 17 Baffle plate 18 Communication pipe 21 Heating heater (heating means)
25 Silica gel

Claims (4)

In an ozone pyrolysis device that thermally decomposes ozone in an ozone-containing gas,
A heat exchange section communicating with the ozone-containing gas inlet;
A heating unit communicating with the heat exchange unit;
A packed portion communicating with the heated portion and filled with any of granular silica gel, zeolite, porous glass, porous ceramic or porous metal crystal;
Heating means for heating the heating unit to a constant temperature in the range of 100 ° C. to 350 ° C. and holding the filling unit at a constant temperature in the range of 100 ° C. to 350 ° C .;
A communication pipe having one end communicating with the filling section and penetrating through the heat exchange section and the other end communicating with the ozone-removed gas outlet;
The ozone-containing gas supplied from the ozone-containing gas inlet to the heating unit via the heat exchange unit is heated to a constant temperature in the range of 100 ° C. to 350 ° C. by the heating means, and the heated ozone-containing gas is 100 The ozone is thermally decomposed by passing through the filling portion maintained at a constant temperature in the range of ℃ to 350 ℃, and the ozone-removed gas is discharged from the ozone-removed gas outlet through the communication pipe, An ozone pyrolysis apparatus, wherein the ozone-containing gas in the heat exchange section is heated by the ozone-removed gas flowing through the communication pipe.   2. The ozone pyrolysis apparatus according to claim 1, further comprising a baffle plate that divides the inside of the heat exchange section into a labyrinth and is coupled to the communication pipe.   The said filling part is provided in the container in which the said ozone containing gas inlet was provided, The inside of the said container was divided into the said heat exchange part and a heating part by this filling part, The Claim 1 or 2 characterized by the above-mentioned. Ozone pyrolysis device.   4. The storage tank according to claim 1, wherein a storage tank is disposed adjacent to the heat exchange section and communicated with the other end of the communication pipe and provided with the ozone-removed gas outlet. Ozone pyrolysis device.

Images