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1. Field of the Invention
The present application relates to a system and a method for producing ozone, and relates more particularly to a system and a method for producing supercritical ozone.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
Ozone with a critical point close to carbon dioxide has an oxidizing power similar to that of fluorine. Moreover, ozone has disinfection capability, naturally decomposes in air, and does not leave any accumulated residue. Therefore, compared with toxic sterilants such as ethylene oxide, formaldehyde and peracetic acid, ozone is environmentally friendly. Due to the above-mentioned advantages, ozone is increasingly applied for sterilization or surface treatment.
Fluid in a supercritical state can have many characteristics. For example, compared with liquid phase medium in a reaction, supercritical fluid can have greater diffusivity, and therefore the supercritical fluid can encounter less mass transfer resistance when it flows through a porous solid catalyst or an interface; compared with gaseous phase medium in a reaction, the supercritical fluid has higher density so as to increase its reaction rate. U.S. Pat. No. 7,219,677 discloses a method and an apparatus for supercritical ozone treatment of a substrate. Oxygen is supplied to an ozone generator for producing ozone. After ozone is injected into deionized water, the ozonated mixture is pressurized to reach its supercritical state using a pressure-boosting pump and then is introduced into a reactor.
In addition, Taiwan Patent Application No. 200726514 discloses a method for producing a mixture of ozone and high pressure carbon dioxide. The method uses an adsorption bed to absorb oxidizer. Next, high pressure fluid flows through the adsorption bed for desorbing the oxidizer and to produce a mixture of oxidizer and high pressure fluid.
Furthermore, U.S. Patent Publication No. 2006/0,102,208 discloses a system for removing a residue from a substrate using supercritical carbon dioxide processing. In this system, the surface of a substrate is pretreated in a process chamber using ozone. Thereafter, the substrate is transferred to a supercritical carbon dioxide cleaning reactor using a transfer system, and thereupon supercritical carbon dioxide is introduced to clean the substrate. The cleaning process requires two reactors, and therefore the system is complex.
To bring ozone into its supercritical state requires a pressure-boosting pump. However, the pressure-boosting pump is expensive, and its sealing components are prone to the erosion effects of high pressure ozone, resulting in leakage issue.
Embodiments of the present disclosure propose a system and method for producing supercritical ozone, which is obtained by introducing high pressure fluid into a reactor to pressurize the gas containing ozone increasingly accumulated at atmospheric pressure in a circulating manner. Therefore, the system and method for producing supercritical ozone of the present disclosure can avoid leakage issue and reduce the cost of production of supercritical ozone.
One embodiment of the present disclosure proposes a system for producing supercritical ozone, which comprises a reactor, an ozone generator, a fluid-driving device, and a fluid source. The reactor includes a first connecting port and a second connecting port. The ozone generator connects to the first connecting port. The fluid-driving device connects to the ozone generator and the second connecting port such that the gas in the reactor can circulate through the ozone generator. The fluid source connects to the reactor, and is configured to pressurize the reactor to an operating pressure to obtain supercritical ozone.
Another embodiment of the present disclosure proposes a method for producing supercritical ozone, which comprises the steps of: circulating gas in a reactor through an ozone generator; and pressurizing the reactor to an operating pressure using pressurized fluid to obtain supercritical ozone.
To better understand the above-described objectives, characteristics and advantages of the present application, embodiments, with reference to the drawings, are provided for detailed explanations.
The application will be described according to the appended drawings in which:
The ozone generator 12 is coupled to the first connecting port 15, and a valve 17 is used to control the fluid flow between the reactor 11 and the ozone generator 12. The fluid-driving device 13 is coupled to the ozone generator 12 and the second connecting port 16, and a valve 18 can be disposed between the fluid-driving device 13 and the second connecting port 16 to control the fluid flow between the reactor 11 and the fluid-driving device 13. The fluid-driving device 13 draws the gas in the reactor 11 from the first connecting port 15 at atmospheric pressure, causing the gas to flow through the ozone generator 12 so as to convert oxygen in the gas into ozone. The gas with higher ozone concentration is then driven back to the reactor 11 by the fluid-driving device 13. Such a circulation process can continuously increase the ozone concentration in the reactor 11. In one embodiment, the fluid-driving device 13 comprises a circulating pump. Because the concentration of ozone is increased under atmospheric pressure, the leakage issue caused by the erosion of high pressure ozone can be avoided. Using a simple ozone generator 12 to produce ozone can prevent generated ozone from containing impurities, and allows the system 1 to have a simple structure and low manufacturing cost.
The system 1 for producing supercritical ozone of one embodiment of the present disclosure may further comprise an oxygen supply 19 configured to connect to the ozone generator 12 for provision of oxygen used for producing ozone. The oxygen supply 19 may comprise an oxygen cylinder or a tank containing compressed air, to which a compressed air pump can be connected for providing compressed air. Between the oxygen supply 19 and the ozone generator 12, a valve 20 can be provided.
As shown in
The reactor 11 can be connected with a temperature regulation device 22 for controlling the temperature of the interior of the reactor 11. The temperature regulation device 22 comprises a heater, a cooler, and a temperature controller, but the disclosure is not limited to the afore-mentioned components. The temperature controller controls the heating and cooling to achieve constant temperature control. The temperature controller can be a PID (proportion, integration, and differentiator) controller.
The system 1 for producing supercritical ozone may further comprise a stirrer 23, which is used when a stirring operation is required. For example, the supercritical ozone and non-sterile liquid can be mixed using the stirrer. The stirrer 23 can be a mechanical stirrer or a magnetic stirrer; however, the present disclosure is not limited to the two examples.
The system 1 for producing supercritical ozone may also comprise a controller 24 configured to use control parameters to control the system 1. For example, the controller 24 can be connected to the temperature regulation device 22 to control the interior temperature of the reactor 11, or the controller 24 can be connected to the valve 21 to control the interior pressure of the reactor 11. The reactor 11 can be disposed with sensors 25 such as temperature sensors or pressure sensors which are connected to the controller 24 to monitor the interior environment of the reactor 11.
After reaction is completed, the gas in the reactor 11 can be directed through the ozone decomposer 26 to convert ozone to oxygen. A valve 27 can be disposed between the ozone decomposer 26 and the reactor 11. The ozone decomposer 26 can comprise activated carbon to decompose ozone, a catalyst such as manganese dioxide to decompose ozone, or a heater to convert ozone to oxygen by heat. The reactor 11 can be a stainless steel enclosed cabin, which can include a pressure vent 30.
The ozone analyzer 28 disposed in the circulation loop 31 is for monitoring an ozone concentration, and can be connected to the controller 24 to control the ozone concentration in the reactor 11. The fluid source 14 may comprise a booster pump 32 with a gas source 33 connected to the booster pump 32. The gas source 33 can be a carbon dioxide source, but the present disclosure is not limited to such example. The booster pump 32 is for increasing the pressure in the reactor 11 so as to bring the ozone in the reactor to the supercritical state. The booster pump 32 can be coupled to the controller 24, whereby the pressure in the reactor 11 can be controlled.
The system 2 for producing supercritical ozone may comprise a carbon dioxide recovery device 29 configured to recover the carbon dioxide used in producing supercritical ozone. The carbon dioxide recovery device 29 may include a heater 34 configured to decompose the ozone mixed with the carbon dioxide.
The above-described ozone generator 12 may comprise a corona discharge ozone generator, an ultraviolet ozone generator, or a plasma ozone generator, but the present disclosure is not limited to such examples. The ozone generator 12 converts a portion of oxygen contained in the gas flowing therethrough into ozone to increase the ozone concentration of the gas.
Moreover, when the system 2 for producing supercritical ozone is operated, the interior temperature of the reactor 11 can be controlled within a range of from 30 to 80 degrees Celsius using the temperature regulation device 22, and the interior pressure of the reactor 12 can be increased to a pressure in a range of from 70 to 300 bars.
Referring back to
As shown in
The reactor 11 can hold non-sterile liquid. After the formation of supercritical fluid including supercritical carbon dioxide and supercritical ozone, a stirrer 23 can be utilized to sufficiently mix the supercritical fluid with the non-sterile liquid in order to sterilize the liquid. The system and method of the embodiments of the present disclosure are not limited to the sterilization application, and can be also used for other applications such as substrate surface cleaning, the oxidative modification of a material surface, wafer etching, and the disinfection and sterilization of medical devices.
After the sterilization process is finished, the pressure in the reactor 11 is reduced to atmospheric pressure. Referring to
In summary, the disclosure proposes a system for producing ozone comprising a circulation loop disposed with an ozone generator, which is used to increase the ozone concentration in the reactor by circulating the fluid in the reactor at atmospheric pressure. The system further includes a fluid source containing high pressure fluid, which is introduced into the reactor so that the ozone in the reactor can reach the supercritical state.
The above-described embodiments of the present application are intended to be illustrative only. Numerous alternative embodiments may be devised by persons skilled in the art without departing from the scope of the following claims.
Number | Date | Country | Kind |
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098136825 | Oct 2009 | TW | national |