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Ozone remediation apparatus and methodsRelated Patent Categories: Gas Separation: Processes, Liquid Contacting (e.g., Sorption, Scrubbing, Etc.), On Surface Extending Mass, Particulate Media, Fibrous Media, Or Packing ElementsOzone remediation apparatus and methods description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070000386, Ozone remediation apparatus and methods. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE TO RELATED APPLICATION [0001] This application is a continuation-in-part of provisional application Ser. No. 60/450,457 filed on Feb. 26, 2003. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH [0002] Not relevant. FIELD OF THE INVENTION [0003] The present invention relates to a method and apparatus for removal of pollution using ozone and/or high pressure oxygen. DESCRIPTION OF THE DRAWINGS [0004] Preferred embodiments of the invention, illustrative of the best modes in which the applicant has contemplated applying the principles, are set forth in the following description and are shown in the drawings and are particularly and distinctly pointed out and set forth in the appended claims. [0005] FIG. 1 is a schematic diagram of an apparatus for using a method of oxidation of gas stream pollutants using a mixture of chlorine dioxide and ozone at elevated pressure in a contact tank or pressure vessel to remove volatile organic compounds (VOCs) and nitrogen oxide (No.sub.x) compounds from the gas stream. DESCRIPTION OF THE PREFERRED EMBODIMENT [0006] As required, detailed embodiments of the present inventions are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Flue Gas Remediation with Ozone and Chlorine Dioxide [0007] Referring now to FIG. 1, the ozone oxidation system for flue gases is shown in schematic form. A stream of flue gas 8 is taken from a boiler flue by vent pipe 11. The amount of flue gas taken from the boiler can be the entire flue gas stream or a portion of the flue gas stream. It will be appreciated that most operators of boilers are attempting to achieve compliance with environmental regulations and therefore the emission of some flue gases into the atmosphere is permitted. Therefore, it is often in the best economic interest of the boiler operator to treat only a portion of the boiler flue by using a side stream take off from the boiler flue and directing that side stream of flue gas into the treatment method and apparatus of the present invention via a side stream take off directed to pipe 11. The flue gases 8 are directed toward venturi 12. In venture 12, the flow of cooling water 16 draws flue gases 8 into venturi 12 and through constriction 12A of venturi 12. In addition cooling water can be sprayed or atomized into flue gasses 8 to cause further mixing of the cooling water with gas stream 8. The flow cooling water into venturi 12 is assisted by pump 14 which draws water 16 from cooling water basin 17 through pipe 18 to pump 14 whereupon it is injected into venturi 12 to draw in and cool flue gases 8 traveling through side stream pipe 11. Once the flue gases have mixed with the cooling water in venturi 12, the flue gas temperature is reduced from as high as 500 degrees Fahrenheit in pipe 11 to a more moderate temperature of about 200 degrees Fahrenheit. It is important to cool the flue gases for two reasons. The first is that oxidizing agents have difficulty functioning with flue gases which are at high temperatures. The second reason is that high temperature flue gases can damage packing 20 contained within scrubber 22. [0008] As the hot flue gases 8 mingle with the cooling water in venturi 12, the cooled gases are drawn out of cooling chamber 24 and into scrubber 22. The flow of gases into scrubber 22 is assisted by exhaust fan 26 which is located in exhaust stack 28 of scrubber 22. Fan 26 serves to pull gases 8 up through scrubber 22. It will be appreciated that while some contaminates are pulled out of flue gas 8 by cooling water 16 as it is sprayed into venturi 12, the amount of contaminates contained in cooling water 16 is relatively small. The first reason for this small transfer is due to the heat of the gases initially and the fact that there is little material contained in cooling water 16 which is able to oxidize any of the pollutants contained in flue gas 8, therefore any transfer of contaminates between the gas phase and the liquid phase will be minimized due to the rapid saturation of cooling water 16 with the limited amount of contaminates that can be held in cooling water 16. [0009] As the cooled flue gases 8 enter scrubber 22, they are drawn upwardly through packing 20 where the flue gases 8 mix with water 32 which is sprayed onto the top of packing 20 by spray head 34. The spray head is positioned near the top of scrubber 22 and above packing 20. The water sprayed by head 34 trickles down through packing 20 and commingles with the flue gases 8 which are traveling upwardly through packing 20. This contact between water 32 and gases 8 causes the transfer of pollutants from the upward moving gases 8 into the water liquid phase 32 which is traveling downwardly through packing 20. Those skilled in the art will appreciate that packing 20 is, to a large degree, inert and does not participate in any sort of chemical manner with either flue gas 8 or water 32 as the water and gas commingle within packing 20. The purpose of scrubber packing 20 is to increase the available surface area in scrubber 22 to provide a greater amount of surface area contact between gas 8 and water 32 to assist the transfer of pollutants between the two phases. The principal object of the scrubber being to remove the contaminates from gas 8 to allow cleaner gas which is compliant with environmental standards to be exhausted through the top of stack 22 through vent 28 past fan 26 and into the atmosphere. [0010] As has been previously stated, during the course of gas 8 traveling through packing 20 of stack 22 and being exposed to water 32 which is being sprayed downwardly from spray head 34, the contaminates in the gas 8 are transferred into the water 32. In particular these contaminates are mainly comprised of volatile organic compounds (VOCs) and nitrous oxide and other oxide compounds of nitrogen (NO.sub.x, generally). Such VOCs and NO.sub.x compounds are the principal contaminates from flue gas, and are removed from gas 8 and absorbed into water phase 32 as the two phases transit packing 20. After leaving packing 20, water 32 will contain some portion, usually a large portion of the contaminates that were previously contained in gas 8, and the contaminates will be carried with the down flowing water into scrubber water basin 36 which is at the base of scrubber 22. [0011] To maintain the operation of scrubber 22, it is necessary to either purge the contaminate filled water 32 which is residing in scrubber water basin 36, or to treat the scrubber basin water 32 and recirculate it within scrubber 22 to remove additional contaminates from flue gases 8. Typically it has been considered to be more environmentally and economically sound to treat contaminate filled water 32 and to then recirculate it within scrubber 22 to remove additional contaminates from flue gases 8. The treatment of contaminated water 32 has, in the past, generally been accomplished using chlorine dioxide (ClO.sub.2) as an oxidizer to reduce or eliminate the VOCs and NO.sub.x that are contained in scrubber water basin water 32. [0012] To clean the scrubber basin water 32 for reuse, water 32 is drawn out of scrubber basin 36 by pump 38 which is attached to scrubber basin 36 by supply line 40. As water is drawn through supply line 40 by pump 38, ClO.sub.2 is added to the water by an input line connected to supply line 40. In typical prior art applications that were not cleaning a hot water such as results from boiler flue gasses 8, only chlorine dioxide was added to the water. The ClO.sub.2 alone was relied upon to oxidize a sufficient amount of VOCs and NO.sub.X to reduce the contaminate level in water 32 sufficiently so additional contaminates could be scrubbed from gases when water 32 was again sprayed onto packing 20 by sprayer head 34. However, in applications in which the gas being cleaned is a flue gas, the temperature of scrubber water 32 can be higher than the normally accepted range for effective use of chlorine dioxide. For example, if the temperature of water 32 after contacting flue gas 8 is greater than 110 degrees Fahrenheit, chlorine dioxide becomes ineffective for use as an oxidant. Similar limitations are present for ozone. Ozone is not very soluble and not very effective in treating contaminants in water when the water temperature approaches 130 to 135 degrees Fahrenheit. With the pressure injection and pressure contact of the present invention, ozone and chlorine dioxide successfully continued to be effective in oxidizing water contaminants at temperatures of up to 140 degrees Fahrenheit. [0013] In the application of the present invention to the cleaning of flue gas, the cooled flue gas, after leaving venturi 12 and cooling chamber 24, is still at a temperature of about 200 degrees when the flue gas 8 enters scrubber 22. While the gas is substantially cooled as it passes through the water filled scrubber packing 22, the heat from gas 8 is transferred to water 32, and thus water 32 in scrubber basin 36 will typically be in excess of 110 degrees and can be as high as 130 degrees. At these temperatures, chlorine dioxide becomes an ineffective means of reducing the VOCs and NO.sub.x contained in the scrubber basin water 32. The present invention, however, avoids this limitation of chlorine dioxide and allows the oxidation of contaminates in scrubber basin water 32 at temperatures as high as approximately 140 degrees Fahrenheit. The apparatus and method which allows this oxidation of higher temperature water to be accomplished will be described hereinafter. [0014] As previously described, contaminate filled scrubber basin water 32 is drawn off of scrubber basin 36 by pump 38, and the water 32 is charged with chlorine dioxide from supply line 40. After leaving pump 38, the chlorine dioxide charged water passes along return pipe 42, and a portion of the chlorine dioxide charged water is diverted into side stream take-off pipe 44. The contaminated water 32 which is not diverted by pipe 44 continues in return pipe 42 to sprayer head 34 at the top of scrubber 22 and is sprayed back onto packing 20 to receive additional contaminates from flue gases 30. [0015] The portion of water 32 which is diverted into take-off pipe 44 is directed toward pump 46. It should be appreciated that under the present apparatus and method, chlorine dioxide can be added in one or both of two locations as is desired by the operator. The first point for injection of chlorine dioxide has been described and is conveniently located in the vicinity of the intake line to pump 38. The second convenient location for injecting chlorine dioxide into the contaminated water 32 is prior to pump 46. In the present apparatus and method, two pumps 38, 46 are utilized as pump 38 is sized to move a larger volume of water between water basin 36 and sprayer head 34, and pump 46 is sized to move a smaller volume of water. That smaller volume of water 32 is the water traveling through pipe 42, toward a means of adding ozone to the chlorine dioxide charged scrubber basin water 32. The water 32, after being charged with ozone, is directed to a pressurized holding chamber 56 wherein the oxidizers are allowed to react with the VOCs and NO.sub.x contained within the scrubber basin water 32. [0016] Now, in further detail, once a portion of scrubber basin water 32 is drawn off of pipe 42 and into pipe 44, it may be charged, or additionally charged, with chlorine dioxide as previously described. Water 32 in line 44 is acted on by pump 46 to raise the pressure of water 32 sufficiently to allow the water to flow through venturi 48 and draw ozone into water 32 through use of venturi 48. Ozone, produced by ozone generator 50, is drawn into the water stream at venturi 48 from line 52. The VOC and NO.sub.x contaminated scrubber basin water 32 which is now charged with both chlorine dioxide and ozone (0.sub.3) is then passed along line 54 and into contact vessel 56. In contact vessel 56, the contaminated scrubber waste water 32 which now contains oxidants chlorine dioxide and ozone is allowed to reside and to mix and to react within contact vessel 56 to reduce the VOCs and NO.sub.x contained within the scrubber basin water 32. The water/chlorine dioxide/ozone and contaminant mixture in contact vessel 56 is under a slight pressure of about 25 pounds per square inch due to the pumping pressure created by pump 46 and the slightly restricted out flow from contact vessel 56 caused by line 58. The combination of the pressure within vessel 56 with ozone allows the ozone and chlorine dioxide to effectively reduce the VOC and NO.sub.x content of scrubber basin water 32 dramatically. This is accomplished while the temperature of water 32 is approximately 110 degrees or greater. Typically, at such a temperature, chlorine dioxide alone would have been ineffective to treat the VOCs and NO.sub.x either from loss of activity or from insolubility of the chlorine dioxide in the hot water. The restriction of outward flow from pressure vessel 56 by pipe 58 and the pressure created by pump 46 provides a sufficient pressure increase within vessel 66 to assist in the oxidation of contaminates by the ozone and chlorine dioxide. After a sufficient reaction time, normally in the range of a few seconds or minutes, within pressure vessel 56, the treated scrubber basin water 32 is allowed to exit pressure vessel 56 along line 58 and rejoin the bulk of the water being transported to sprayer head 34 in line 42. [0017] As an alternative to using chlorine dioxide in combination with ozone, sulfuric acid may be used as an agent to lower the pH of the water into which the ozone is mixed. It has been observed that the use of the chlorine dioxide in the water has the effect of lowering the pH of the water. The use of sulfuric acid and, potentially, other inexpensive acids, as a pH lowering agent also appears to permit ozone to function effectively in oxidizing water contaminants at temperatures of up to 140 degrees Fahrenheit while reducing costs of operation. Most users of ozone insist on neutral or high pH environments to promote the formation of hydroxyl radicals. by contrast the present invention operates with a low pH to provide effective results for paper mill black liquor and recycled oil/antifreeze wastewater processes. High Pressure Ozone Sparging Device Continue reading about Ozone remediation apparatus and methods... 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