System for producing aqueous halogen solutions having various compositions

Abstract

A method and system for the controlled production of aqueous halogen solutions with various compositions is disclosed. According to one embodiment, an aqueous solution of hypochlorite ions is modified by sequentially adding a pH-adjusting chemical, a non-chloride halide ion, and a halogen-stabilizing compound. A sensor for measuring the physical and chemical properties of the solution when it changes due to the influence of various chemical reactions is connected to a control system, which can then control the dosage of one or more chemicals. This control system facilitates the production of solutions with desired properties in terms of pH, specific halogen composition, degree of halogen stabilization, and limiting the production of undesirable by-products such as bromate ions.

Description

[Technical field]

[0001] The present invention relates to the preparation of aqueous halide solutions in a controlled manner. In particular, the present invention relates to the preparation of aqueous solutions of various compositions having at least two aqueous halide species. System for manufacturing Regarding. [Background technology]

[0002] Aqueous halogen solutions are used as biocides in many water treatment processes, such as disinfection of drinking water, wastewater, water used in industrial cooling towers, irrigation water, and water used in oil and gas production operations. Aqueous solutions of hypochlorite ions are most commonly used in these applications, but other aqueous halogen species, such as stabilized bromine solutions, are also often used. Aqueous solutions having two or more aqueous halogen components are desirable in that they can provide many benefits in water treatment processes, such as improved, complementary, or synergistic bactericidal properties, or properties that can be secondary benefits, such as reduced corrosivity and improved halogen stability. Summary of the Invention

[0003] One or more embodiments of the present invention relate to a method and system for the controlled production of an aqueous halogen solution having at least two aqueous halogen species. According to one embodiment, a system for controlling the production of an aqueous halogen solution having at least two aqueous halogen species is provided. The system includes an initial hypochlorite solution, a chemical for controlling the pH of the initial hypochlorite solution, one or more components configured to provide at least one additional halide ion and, if desired, to provide at least one halogen stabilizing compound. The system further includes a control system having a number of sensors capable of monitoring the chemical and physical properties of the aqueous solution, a computer control system, and various pumping mechanisms damped by the computer control system. The system further includes a control system for optimizing the production of a desired solution composed of at least two aqueous halogen species and minimizing or eliminating the generation of undesirable chemical species.

[0004] According to another embodiment, a method for controlling the production of an aqueous halogen solution having at least two aqueous halogen species is provided.The method includes modifying an aqueous solution of hypochlorite ions by sequentially adding a pH adjusting chemical, a halide ion, and a halogen stabilizing compound.A sensor for measuring the physical and chemical properties of the solution as they change due to the influence of various chemical reactions is connected to a control system, which can then control the dosage of one or more chemicals.The control system facilitates the production of a solution with desired properties in terms of pH, the composition of specific halogens, the degree of halogen stabilization, and the limiting of the production of undesirable by-products such as bromate ions.

[0005] According to one embodiment, a system for producing a mixed aqueous halogen solution having at least two distinct halogen species includes: (i) a first storage tank containing an aqueous halogen solution that does not contain chlorine; (ii) one or more mixing tanks including a flow impediment structure, the first mixing tank being disposed downstream of the first storage tank; and (iii) piping for moving a stream of aqueous hypochlorite solution to the first mixing tank. The flow impediment structure can include one or more baffles. The aqueous halogen solution is a bromine-containing fluid. Alternatively, the aqueous halogen solution includes bromine and iodine. The system can further include a second storage tank for containing the aqueous hypochlorite solution. The piping is configured to move the aqueous hypochlorite solution from the second storage tank to the first mixing tank. The second storage tank is disposed upstream of the first mixing tank.

[0006] In another embodiment, the system includes an in situ device for generating an aqueous hypochlorite solution. The device can include a conventional electrolytic cell. The piping is configured to transfer the aqueous hypochlorite solution from the device. The device is disposed upstream of the first mixing tank.

[0007] The system may further include an optional third storage tank containing a pH adjusting chemical. A static mixer is provided for mixing the aqueous hypochlorite solution with a pH adjusting chemical prior to delivery to the first mixing tank.

[0008] The system can include a first sensor group, the first sensor group being fluidly connected to the static mixer, the first sensor group including one or more sensors for at least measuring a pH of the aqueous hypochlorite solution or a pH of the pH-adjusted aqueous hypochlorite solution prior to delivery to the first mixing tank.

[0009] In the first mixing tank, the baffles are configured to promote sufficient mixing of (a) the aqueous hypochlorite solution, or the pH adjusted aqueous hypochlorite solution, and (b) the chlorine-free aqueous halogen solution to produce a mixed aqueous halogen solution having at least two distinct halogen species.

[0010] The system further includes a second sensor group disposed downstream of the first mixing tank. The second sensor group includes one or more sensors for measuring one or more parameters of the mixed aqueous halogen solution. The parameters can be selected from the group consisting of pH, oxidation-reduction potential (ORP), UV-Vis absorption profile, and combinations thereof.

[0011] The system further includes a fourth storage tank. The fourth storage tank is fluidly connected to the second group of sensors. The fourth storage tank is configured to contain a halogen stabilizing compound.

[0012] The piping means transfers the mixed aqueous halogen solution and the halogen stabilizing compound to a second mixing tank that includes one or more baffles configured to promote sufficient mixing of (a) the mixed aqueous halogen solution and (b) the halogen stabilizing compound to produce a stabilized mixed aqueous halogen solution having at least two distinct halogen species.

[0013] A fifth storage tank is disposed downstream of the second mixing tank. The stabilized mixed aqueous halogen solution is delivered to the fifth storage tank. According to another embodiment, a method for producing a mixed aqueous halogen solution having at least two distinct halogen species includes pumping a stream of an aqueous hypochlorite solution to a first mixing tank; pumping an aqueous halogen solution to the first mixing tank, the aqueous halogen solution being free of chlorine; and facilitating sufficient mixing of the aqueous hypochlorite solution and the chlorine-free aqueous halogen solution in the first mixing tank to produce a mixed aqueous halogen solution having at least two distinct halogen species.

[0014] The method further includes measuring (i) at least a pH of the aqueous hypochlorite solution prior to passing to the first mixing tank; and (ii) one or more parameters of the mixed aqueous halogen solution, the parameters being selected from the group consisting of pH, oxidation-reduction potential (ORP), UV-Vis absorption profile, and combinations thereof.

[0015] These measurements are processed to control the flow rate of the aqueous hypochlorite solution into the first mixing tank. These measurements can also be used to control the pumping rate of at least one of the aqueous hypochlorite solution and the aqueous halogen solution to control the reaction between the hypochlorite ions and the non-chloride halide ions in the first mixing tank.

[0016] The objects, advantages, novel features, and further scope of applicability of the present invention will be set forth in part in the following detailed description taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon the experimentation of the following or may be learned by the practice of the invention. The objects and advantages of the present invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the following description.

[0017] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate several embodiments of the invention and, together with the description, serve to explain the principles of the invention. The drawings are intended merely to illustrate a preferred embodiment of the invention and are not to be construed as limiting the invention. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 illustrates one embodiment of a system for producing a mixed aqueous halogen solution. [Diagram 2] FIG. 2 illustrates one embodiment of a system for producing a stabilized mixed aqueous halogen solution. [Diagram 3] FIG. 3 illustrates one embodiment of a system for producing an aqueous mixed halogen solution using sodium hypochlorite produced by an electrolysis system as the initial halogen source. [Figure 4] FIG. 4 illustrates one embodiment of a system for producing a stabilized mixed-halogen aqueous solution using sodium hypochlorite produced by an electrolysis system as the initial halogen source. [Diagram 5] FIG. 5 illustrates one embodiment of a UV sensor system. [Figure 6] FIG. 6 illustrates one embodiment of a system for producing a stabilized mixed-halogen aqueous solution using an electrolysis process in which a pH adjusted mixed halide brine is electrolyzed to produce a mixture of aqueous free halogens, which then reacts with a halogen stabilizing compound. [Figure 7] FIG. 7 is a graph showing the UV-Vis absorption spectrum of the aqueous halogen solution prepared as described in Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The embodiment of the present invention and the implementation of the present invention are intended to produce an aqueous solution having at least two or more different aqueous halogen species with any desired ratio between the two or more aqueous halogen species.Within the scope of the present invention, the term "aqueous halogen species" includes dissolved halogens (molecular chlorine, molecular bromine, and molecular iodine), hypohalous acids (hypochlorous acid, hypobromous acid, and hypoiodous acid), hypohalite ions (hypochlorite, hypobromite, and hypoiodite), and haloamine species (any compound having at least one nitrogen atom, where the nitrogen atom contains at least one chemical bond to at least one halogen atom).

[0020] The oxidation of bromide and iodide ions by hypochlorite ions is well known in the art and proceeds according to the following equation: ClO - +Br - →BrO - +Cl - ClO - +I - →IO - +Cl - As shown, hypochlorite ion (ClO - ) is the bromide ion (Br - ) to produce hypobromite ion (BrO - ) or iodide ion (I - ) to produce hypoiodite ions (IO - ), and in both cases the hypochlorite ion is reduced to chloride ion (Cl - )

[0021] In practice, aqueous halogen, especially aqueous bromine and iodine, is stabilized by mixing the aqueous halogen with a halogen stabilizing compound. As used herein, the term "halogen stabilizing compound" includes organic or inorganic amine compounds that contain at least one nitrogen atom and at least one nitrogen-hydrogen bond. When the aqueous halogen and the halogen stabilizing compound are mixed together, the aqueous halogen reacts with the halogen stabilizing compound to convert the nitrogen-hydrogen bond to a nitrogen-halogen bond, effectively producing an N-haloamine compound. Halogen stabilizing compounds can include, but are not limited to, sulfamic acid, sulfamate, hydantoin, 5,5-dimethylhydantoin, taurine, and cyanuric acid.

[0022] In the practice of the present invention, it has been shown that the reaction between the initial hypochlorite ions, the additional halide ions, and the halogen stabilizing compound affects the physical and chemical properties of the solution, such as changes in the solution's pH, oxidation-reduction potential (ORP), and the absorption profile of the solution in the ultraviolet and visible (UV-Vis absorption profile) range of wavelengths (herein, this wavelength range is between 200-800 nm). According to one or more embodiments, these changes can be measured (e.g., using sensors) to find mechanisms for controlling both the overall process and the solutions produced by the process. This allows for optimal utilization of all chemicals used in the process and the reduction of bromate ions (BrO 3 - ) is desirable to avoid the undesirable generation of any undesirable chemical species.

[0023] FIG. 1 shows a schematic diagram of a system 100 for controlled production of mixed halogen aqueous solution. Fresh water is delivered to the system 100 by a pipe 2. As used herein, the term "pipe" means a tube or line for conveying fluids and solutions. A tank 4 contains an aqueous hypochlorite solution, which is pumped into the pipe 2 by the action of a pump 6. Preferably, the aqueous hypochlorite solution contained in the tank 4 is electrochemically generated, and the concentration of hypochlorite ions in the diluted stream is about 3,000 mg / L or less. In one embodiment, the aqueous hypochlorite solution contained in the tank 4 can include sodium hypochlorite. However, it is understood that any solution that is mainly composed of at least one hypochlorite-containing compound can be used here.

[0024] In one embodiment, the pH of the solution can be adjusted at this stage. For example, tank 8 can contain a solution having at least one pH adjusting chemical dissolved in water, which can be mixed with the aqueous hypochlorite solution in pipe 2 by the action of pump 10. According to one embodiment, the solution contained in tank 8 can include sodium hydroxide dissolved in water. However, it will be understood that any pH adjusting chemical capable of adjusting the pH of the hypochlorite ion-containing solution to a desired pH can be used. In one or more embodiments, the pH adjusting chemical can adjust the pH of the hypochlorite solution to between 10 and 12. In another embodiment, the pH of the hypochlorite solution can be adjusted to between 10.5 and 11.5.

[0025] The resulting diluted hypochlorite solution is then passed through static mixer 12 where it is thoroughly mixed. It is then passed through a first sensor group 14. According to one embodiment, sensor group 14 is configured to at least measure the pH of the diluted hypochlorite solution, although it will be appreciated that sensor group 14 may be configured to measure other solution parameters.

[0026] Tank 16 contains an aqueous halide solution having at least one halide ion. The aqueous halide solution is pumped into pipe 2 by the action of pump 18. According to one embodiment, the aqueous halide solution contained in tank 16 may be either sodium bromide or sodium iodide dissolved in water. However, it will be understood that a combination of these two compounds or any solution containing at least one compound having at least one bromide or iodide ion component, such as, but not limited to, quaternary ammonium bromide and quaternary ammonium iodide compounds, may be used.

[0027] The combined halogen solution can be delivered into a mixing tank 20. In one or more embodiments, the mixing tank 20 can include a flow impeding structure. In one embodiment, the flow impeding structure is a series of baffles 22. The baffles 22 can be constructed of a material such as polyvinyl chloride or any other suitable material that is compatible with the combined halogen solution formed in the system. The baffles 22 are designed to impede the flow of the combined halogen solution through the tank 20 to obtain a desired mixing time. In one or more embodiments, the baffles 22 can include plates or other conventional structures that can impede or slow the flow of the combined halogen solution through the tank 20 so that the solution exiting the tank 20 is thoroughly mixed. This mixing time desirably allows for completion of any chemical reactions that may occur between the hypochlorite ions from tank 4 and at least one halide ion from tank 16. The mixing time can be between 1 minute and 10 minutes.

[0028] The fully reacted / mixed solution then exits the tank 20 along pipe 24, passes through a second set of sensors 26, and travels into tank 28. According to one embodiment, the second set of sensors 26 may be configured to measure at least the pH, ORP, or UV-Vis absorption profile of the diluted mixed halogen solution. However, the second set of sensors 26 may be configured to measure other solution parameters. The mixed halogen solution exits the tank 28 along pipe 30 by the action of pump 32 and into pipe 34. Pipe 34 may be configured to deliver the mixed halogen solution to a point of use (not shown). As one skilled in the art will recognize, the point of use may vary depending on the details of the water treatment process. In one or more embodiments, this may include a cooling tower basin, a swimming pool recirculation line, or the like.

[0029] The composition of the mixed halogen solution can be adjusted by controlling the chemical reaction occurring between hypochlorite ions from tank 4, pH adjusting chemicals from tank 8, and at least one halide ion from tank 16. The first sensor group 14 and the second sensor group 26 can be connected to a control system (not shown). The control system can control one or more characteristics such as: (i) the flow rate of water into pipe 2; and (ii) the pumping speeds of pumps 6, 10, and 18. By controlling the flow rates, the relative amounts of chemicals added into system 100 are effectively controlled, thereby allowing precise amounts of sodium bromide to be added to produce a solution of a desired composition. The control system can facilitate the production of a mixed aqueous halogen solution having specific relative concentrations of aqueous halogen species.

[0030] Alternatively, in another embodiment, both non-chloride halide ions and a halogen stabilizing compound can be introduced simultaneously into the stream containing sodium hypochlorite. For example, tank 16 can contain a solution having both at least one non-chloride halide ion and at least one halogen stabilizing compound, which are injected into the sodium hypochlorite stream present in pipe 2. Simultaneous addition of both at least one non-chloride halide ion and at least one halogen stabilizing compound to the hypochlorite stream can provide process benefits such as simplification of the production of the desired mixed halogen solution. For example, instead of requiring independent control of two inputs, according to one or more embodiments, the injection of the combination of non-chloride halide solution and halogen stabilizer requires control of only one injection. This can also simplify logistics during the implementation of the invention by having one consumable instead of two, and can also reduce costs.

[0031] Many of the details of the above discussion regarding Figure 1 apply to the other embodiments shown in Figures 2-4. For example, in Figures 2-4, like numbers are used to denote like elements and perform the same functions. Thus, for the sake of brevity, the following description focuses on the differences between the embodiment of the invention discussed in Figure 1 and the embodiment of the inventive concepts discussed below with respect to Figures 2-4.

[0032] FIG. 2 shows another embodiment of a system 200 configured to produce an aqueous halogen stabilizing mixture. As shown in FIG. 1, the combined and thoroughly mixed halogen solution is conveyed through pipe 24 and passes through second sensor group 26. Tank 66 contains an aqueous solution of at least one halogen stabilizing compound, which is pumped into pipe 24 by the action of pump 68. The aqueous solution of at least one halogen stabilizing compound may include sodium sulfamate dissolved in water. However, any other halogen stabilizing compound may be used according to one or more embodiments of the present invention, such as, but not limited to, sulfamic acid, potassium sulfamate, taurine, glycine, hydantoin, 5,5-dimethylhydantoin, cyanuric acid, or any combination thereof. The combined solution of the mixed aqueous halogen solution and the halogen stabilizing compound then moves into a second mixing tank 70. The second mixing tank 70 includes a series of baffles 72 (similar to mixing tank 22). Baffle 72 is configured to regulate the flow of the combined solution through tank 70 to provide a desired mixing time that desirably allows for completion of any chemical reactions that may occur between the combined aqueous halogen solution and the halogen stabilizing compound introduced from tank 66.

[0033] The fully reacted / mixed solution then exits tank 70 along pipe 74 where the solution passes through a third set of sensors 76. According to one embodiment, third set of sensors 76 may be configured to measure at least the pH, ORP, or UV-Vis absorption profile of the diluted hypochlorite solution. However, third set of sensors 76 may also be configured to measure other solution parameters. The stabilizing solution then travels into tank 78 where it may be pumped by the action of pump 82 along pipe 80 to pipe 84 from where it is delivered to a point of use (not shown).

[0034] The telemetry data from the first, second, and third sensor groups 14, 26, and 76 can be connected to a control system. The control system can control (i) the flow of water into the pipe 2; and (ii) the pumping speeds of the pumps 6, 10, 18, 68, and 82. Thus, the system 200 is configured to optionally control the chemical reactions occurring between the hypochlorite ions from the tank 4, the pH adjusting chemical from the tank 8, the at least one halide ion from the tank 16, and the at least one halogen stabilizing compound in the tank 66. The control system facilitates the production of a stabilized solution of mixed aqueous halogen having a specific relative concentration of aqueous halogen species and a degree of stabilization of said aqueous halogen species. By controlling the flow rates, the relative amounts of chemicals added into the system 200 are effectively controlled, thereby allowing the addition of precise amounts of hypochlorite ions, sodium bromide, and sulfamic acid (or other halogen stabilizer) to produce a stabilized solution of a desired composition. That is, the composition of the solution is automatically adjusted in real time by varying the amounts of hypochlorite, bromide (or non-chloride halide), and sulfamic acid (or other halogen stabilizer) that are mixed together so that the final product / solution has the desired amount of FAC and free residual bromine FAB before being sent to the point of use.

[0035] FIG. 3 shows another embodiment of a system 300 for producing a mixed halogen solution, which can use an electrolytic cell or electrolysis system to obtain hypochlorite ions. As shown, the system 300 includes an on-site / in situ electrolysis system / hypochlorite generation system 90 for producing a hypochlorite ion stream. Unlike the embodiment shown in FIG. 1, the embodiment 300 shown in FIG. 3 can be used to directly produce a solution of stabilized hypochlorite using the electrolysis system 90. The system 300 involves the electrolysis of a brine solution of at least one chloride-containing salt, preferably sodium chloride, and at least one halogen-stabilizing compound, preferably sulfamic acid. When the brine is electrolyzed, a stabilized halogen solution is produced, which can then be further reacted with bromide or iodide ions introduced into the solution downstream of the electrolysis system 90.

[0036] According to one embodiment, the hypochlorite ion concentration is about 3,000 mg / L or less. The remaining elements and processes are as shown in Figure 1 and will not be repeated here for the sake of brevity.

[0037] Alternatively, this embodiment can be used to simultaneously introduce both non-chloride halide ions and a halogen stabilizing compound into a stream composed of sodium hypochlorite. For example, tank 16 can contain a solution containing both at least one non-chloride halide ion and at least one halogen stabilizing compound, which can then be injected into the sodium hypochlorite solution produced by electrolysis system 90. By simultaneously adding both at least one non-chloride halide ion and at least one halogen stabilizing compound to the hypochlorite stream, process advantages can be obtained, such as simplified production of the desired mixed halogen solution.

[0038] FIG. 4 shows an embodiment of a system 400 for producing a stabilized mixed halogen solution, which can use an on-site electrolysis system to obtain hypochlorite ions. In this embodiment, an on-site hypochlorite generation system 90 produces an aqueous hypochlorite ion stream having a hypochlorite ion concentration of preferably about 3,000 mg / L or less. As shown in the system 400, the on-site hypochlorite generation system 90 can include any conventional electrochemical cell configured to produce an oxidant solution containing at least one hypochlorite species by electrolysis of an aqueous brine having at least one halide-containing salt. The halide-containing salt used in this process is sodium chloride, although any salt containing at least one chloride ion component can be used. The remaining process and elements are as shown in FIG. 2 and will not be repeated here for brevity.

[0039] In one or more embodiments of the present invention, a mixing tank with internal baffles is intended to provide both thorough mixing of the aqueous halogen solution and sufficient time for any desired chemical reactions to occur. It will be apparent to one skilled in the art that other equivalent physical structures, such as mixing loops or in-line mixers, can be used for the same purposes as the baffles described herein.

[0040] In one or more embodiments of the present invention, the sensor group provides telemetry data to control all aspects of the process to ensure the achievement of a desired outcome. For example, the desired outcome may be the production of an aqueous solution having at least two halogen species, with or without chemical stability of these halogen species. In one or more embodiments, the telemetry data from the sensor group described herein is automatically transmitted to a control system. The control system monitors and analyzes one or more properties of the solution to adjust the composition of the solution, such as the ratio of bromine to chlorine and / or the ratio of stabilized halogen to free halogen. The properties may include, but are not limited to, the pH, temperature, oxidant concentration, oxidation / reduction potential (ORP), and ultraviolet absorbance profile of the aqueous solution. The control system may be configured to automatically adjust the composition of the solution in real time by adjusting functional aspects such as (i) flow rates; and / or (ii) injection rates of the various chemicals used in the process, for example, by varying the amount of hypochlorite ions, bromide (or other non-chlorine halide) ions, and sulfamic acid (or other halogen stabilizer) that are mixed in. By controlling these aspects, one can ensure that the final product / solution has the desired free available chlorine (FAC) and free available bromine (FAB) amounts before being sent to the point of use. For example, telemetry data obtained by the sensor array can be used to obtain information, either directly or indirectly, about the composition of the solution with respect to the types of halogens present, and the degree of stabilization.

[0041] For example, the sensor can be used to measure the UV-Vis absorption profile of the aqueous halogen solution produced in one or more embodiments. Since various aqueous halogen species have different UV-Vis absorption profiles, the telemetry data from the sensor can be used to determine the relative concentrations of aqueous halogen and stabilized aqueous halogen present in the solution. For example, as shown in FIG. 7, the relative intensity of the two peaks can be used to determine the amount of both bromine and chlorine in the produced solution. The sensor measures the absorption profile of the product solution and transmits it to the control system. The control system can include a processor and a memory. The processor is configured to process software loaded into the memory to correlate the absorption profile with predetermined data regarding the composition of the desired product solution. In one or more embodiments, the measured pH or ORP can be correlated with predetermined data regarding the composition of the desired product solution. This data can then be used by the control system to inject either more or less bromide, for example, depending on how much bromine is desired in the final product solution.

[0042] Aqueous halogen species and stabilized aqueous halogen species that can be measured using one or more embodiments include dissolved molecular chlorine, dissolved molecular bromine, dissolved molecular iodine, hypochlorous acid, hypobromous acid, hypoiodine acid, hypochlorite ion, hypobromite ion, hypoiodite ion, N-chlorosulfamate, N-bromosulfamate, N-iodosulfamate, N-chlorosulfamic acid, N-bromosulfamic acid, N-iodosulfamic acid, N-chlorotaurine, N-bromotaurine, N-iodotaurine, N,N-dichlorotaurine, N,N-dibromotaurine, N,N-diiodotaurine, N-bromo-N-chlorotaurine, N-bromo-N-iodotaurine, N-chloro-N-iodotaurine, 1 ... 1-bromo-5,5-dimethylhydantoin, 1-iodo-5,5-dimethylhydantoin, 1,3-dichloro-5,5-dimethylhydantoin, 1,3-dibromo-5,5-dimethylhydantoin, 1,3-diiodo-5,5-dimethylhydantoin, 1-chloro-3-bromo-5,5-dimethylhydantoin, 1-chloro-3-iodo-5,5-dimethylhydantoin, 1-bromo-3-chloro-5,5-dimethylhydantoin, 1-bromo-3-iodo-5,5-dimethylhydantoin, 1-iodo-3-chloro-5,5-dimethylhydantoin, 1-iodo-3-bromo-5,5-dimethylhydantoin, or a combination thereof.

[0043] Another embodiment of the present invention is shown in FIG. 5. This embodiment discloses a method of diluting the final product stream to enable the use of UV-Vis spectroscopy to characterize the composition of the mixed halogen solution. As shown, pipe 180 carries the entire / main flow of the solution to be analyzed. Valve 182 is configured to split the flow into a small side stream with a flow rate of preferably 1% or less of the total flow rate in pipe 180. In one or more embodiments, it is about 0.1% to about 1% of the total flow rate. This main side stream is sent along pipe 184 into analyzer 186 for analysis. Dilution water is carried along pipe 188 where it is mixed with a pH adjusting chemical, such as sodium hydroxide, contained in tank 190. The pH of the solution affects the absorption spectrum of the aqueous halogen. Therefore, the pH of the solution is controlled so that the pH of the diluted solution does not drop to a value that would interfere with the measurement of the spectral profile of the solution to be analyzed. In one or more embodiments, this pH can be greater than 10, and preferably greater than 11. The diluted solution enters the analyzer 186 after being pumped into pipe 188 by the action of pump 192. A pH adjusting chemical is added so that the pH of the dilution water matches the pH of the solution to be analyzed. In the analyzer 186, the streams from pipes 184 and 188 are combined so that the diluted solution contains a total oxidant concentration between 50 and 250 mg / L. The combined stream is then passed through an ultraviolet sensor configured to measure the absorbance of the solution in the range of 200 to 800 nm. The combined stream then exits the analyzer 186 along pipe 194 and into valve 196 where the solution is combined with the original total stream from line 180.

[0044] The control system used in one or more embodiments is further configured to prevent the formation of undesirable by-products of various chemical reactions. For example, the reaction between hypochlorite ions and bromide ions can produce bromate ions (BrO) under certain reaction conditions, particularly when the reaction is carried out at a pH below about 10. 3 -) can be generated. Therefore, one function of the sensor group used in this embodiment is to adjust the pH of the hypochlorite ion solution to above 10 before introducing additional halide ions.

[0045] FIG. 6 shows an embodiment of a system 600 having an electrolysis process for producing a solution having mixed free halogens, which are subsequently stabilized by adding a halogen stabilizing compound. In this embodiment, a pipe 201 is used to pump water to the system 600 by pumping means (not shown). A tank 202 contains a solution having at least one halide ion-containing salt dissolved in the water. According to one embodiment, the at least one halide ion-containing salt dissolved in the water is sodium chloride. However, it will be understood that any salt containing halide ions may potentially be used in this or other embodiments. A pump 204 is used to move the solution contained in the tank 202 to the pipe 201.

[0046] Tank 206 contains a solution comprised of a second halide ion-containing salt, which is different from the halide ions of the salt dissolved in the water in tank 202. According to one embodiment, the second halide ion-containing salt dissolved in the water in tank 206 is sodium bromide, although any halide ion-containing salt different from the halide ions of the salt dissolved in the water in tank 202 may optionally be used in this embodiment. Pump 208 is used to move the solution contained in tank 206 through pipe 200.

[0047] In one embodiment, the pH of the solution can be adjusted at this stage. For example, tank 210 contains a solution having at least one pH adjusting chemical dissolved in the water. According to one embodiment, the pH adjusting chemical dissolved in the water in tank 210 is sodium hydroxide. However, it will be understood that any chemical capable of adjusting the pH of an aqueous solution can be used in accordance with this embodiment. Pump 212 is used to move the solution contained in tank 210 into pipe 201. The combined solution is then passed through in-line static mixer 214, past sensors 216, and into electrolysis system 218.

[0048] According to one embodiment, the sensors 216 are configured to at least measure the pH of the diluted hypochlorite solution. However, the sensors 216 may be configured to measure other solution parameters. The sensors 216 may ensure that the mixed halide brine contained in the pipe 200 is at a desired pH, and telemetry data from the sensors 216 is sent to a control system (not shown) that is configured to vary the amount of pH adjusting chemical pumped from the tank 210 into the line 200 using the pump 212.

[0049] The electrolysis system 218 includes an electrolyzer (not shown) capable of electrolyzing a mixed halide ion brine to produce a solution having mixed aqueous halogens. This solution exits the electrolysis system 218 along pipe 220 and passes through a second sensor group 220. According to one embodiment, the sensor group 220 is configured to measure at least the pH, ORP, or UV-Vis absorption profile of the diluted hypochlorite solution. However, the sensor group 220 can be configured to measure other solution parameters.

[0050] Tank 224 contains a solution having at least one halogen stabilizing compound dissolved in water. According to one embodiment, the at least one halogen stabilizing compound dissolved in the water in tank 202 is sulfamic acid, although any halogen stabilizing compound, or mixtures thereof, can be used. A pump 226 can be used to move the solution contained in tank 224 to pipe 220. The combined solution then moves into a mixing tank 228 that includes a series of baffles 230. Baffles 230 are configured to regulate the flow of the solution through the tank to obtain a desired mixing time. This mixing time is desirably sufficient to allow for completion of the chemical reaction that occurs between the mixed aqueous halogen solution and the halogen stabilizing compound introduced from tank 224.

[0051] The fully reacted solution then exits tank 228 where it passes through a third sensor group 232. According to one embodiment, sensor group 232 is configured to measure at least the pH, ORP, or UV-Vis absorption profile of the diluted hypochlorite solution, although sensor group 232 may also be configured to measure other solution parameters.

[0052] Telemetry data obtained by sensors 232 is preferably used to measure properties of the solution to ensure that the formation of the desired stabilized halogen solution has been achieved. Telemetry data from sensors 232 is further used by a control system, not specifically shown herein, to control aspects of the system, such as the flow rate and injection rate of the halogen stabilized compound solution contained within tank 224, to ensure that a stabilized halogen solution has been achieved. The solution is then moved into tank 234, where it then moves out along line 236 by the action of pump 238 to line 240, from which the solution is pumped to a point of use. EXAMPLES

[0053] Various examples are presented below, the data of which provide correlations between measured and monitored solution properties, such as ORP and pH, and solution composition with respect to bromine and chlorine, and stabilized and unstabilized halogens.

[0054] Example 1 A sodium hypochlorite solution was prepared using an on-site hypochlorite generation system by electrolysis of sodium chloride brine to yield a solution with a free residual chlorine (FAC) concentration of 3450 mg / L, a pH of 8.94, and an oxidation-reduction potential (ORP) of 813 mV. Four 200 mL samples of this solution were prepared and reacted with 0.1 g, 0.2 g, 0.4 g, and 2.0 g of sodium bromide to produce a series of mixed halogen solutions. The pH, ORP, FAC content, and free residual bromine (FAB) content of each solution were measured and are reported in the table below.

[0055] [Table 1] Example 2 A sodium hypochlorite solution was prepared using an on-site generation system by electrolysis of sodium chloride brine. After electrolysis, the pH of the solution was adjusted to 11.16 by adding sodium hydroxide to give a solution with a FAC concentration of 3375 mg / L and an ORP of 427 mV. Four 200 mL samples of this solution were prepared and reacted with 0.098 g, 0.2 g, 0.398 g, and 1.98 g of sodium bromide to produce a series of mixed halogen solutions. The pH, ORP, FAC content, and FAB content of each solution were measured and are reported in the table below. The initial sodium hypochlorite solution and the product solutions were diluted with deionized water to FAC concentrations of 95-105 mg / L, and then ultraviolet-visible (UV-Vis) absorption spectra of the resulting solutions were recorded. A graph showing the changes in these spectra in the wavelength range of 225-450 nm is shown in FIG. 7.

[0056] [Table 2] Example 3 An aqueous chlorine solution with a FAC concentration of 3800 mg / L was prepared by electrolysis. The ORP value of this solution was measured to be 795 mV and the pH was 9.04. Three 200 mL samples of this solution were prepared and reacted with 0.3 g, 1.3 g, and 2.6 g of sodium sulfamate to produce sulfamate stabilized halogen solutions. The pH, ORP, FAC content, FAB content, and total chlorine (TC) content of each solution were measured and are reported in the table below.

[0057] [Table 3] Example 4 A mixed halogen solution consisting of aqueous chlorine and aqueous bromine was prepared by adding 0.76 g of sodium bromide to 700 mL of an aqueous chlorine solution with an FAC concentration of 3800 mg / L prepared by electrolysis. The ORP value of this solution was measured to be 796 mV and the pH was 9.26. Three 200 mL samples of this solution were prepared and reacted with 0.3 g, 1.3 g, and 2.6 g of sodium sulfamate to produce sulfamate-stabilized halogen solutions. The pH, ORP, FAC content, FAB content, and total chlorine (TC) content of each solution were measured and are reported in the table below.

[0058] [Table 4] Example 5 A mixed halogen solution consisting of aqueous chlorine and aqueous bromine was prepared by adding 7.6 g of sodium bromide to 700 mL of an aqueous chlorine solution with an FAC concentration of 3800 mg / L prepared by electrolysis. The ORP value of this solution was measured to be 786 mV and the pH was 9.68. Three 200 mL samples of this solution were prepared and reacted with 0.3 g, 1.3 g, and 2.6 g of sodium sulfamate to produce sulfamate-stabilized halogen solutions. The pH, ORP, FAC content, FAB content, and total chlorine (TC) content of each solution were measured and are reported in the table below.

[0059] [Table 5] Example 6 An aqueous chlorine solution with a FAC concentration of 3600 mg / L was prepared by electrolysis, the pH was adjusted to 10.98, and the resulting solution had an ORP value of 585 mV. Three 200 mL samples of this solution were prepared and reacted with 0.25 g, 1.3 g, and 2.5 g of sodium sulfamate to produce sulfamate-stabilized halogen solutions. The pH, ORP, FAC content, FAB content, and total chlorine (TC) content of each solution were measured and are reported in the table below.

[0060] [Table 6] Example 7 A mixed halogen solution consisting of aqueous chlorine and aqueous bromine was prepared by adding 0.72 g of sodium bromide to 700 mL of an aqueous chlorine solution with an FAC concentration of 3600 mg / L prepared by electrolysis. The reaction between hypochlorite and bromide was allowed to proceed to completion, and the pH of the mixed halogen solution was then adjusted to 10.85. This solution had an ORP value of 649 mV. Three 200 mL samples of this solution were prepared and reacted with 0.25 g, 1.3 g, and 2.5 g of sodium sulfamate to produce sulfamate-stabilized halogen solutions. The pH, ORP, FAC content, FAB content, and total chlorine (TC) content of each solution were measured and are reported in the table below.

[0061] [Table 7] Example 8 A mixed halogen solution consisting of aqueous chlorine and aqueous bromine was prepared by adding 7.2 g of sodium bromide to 700 mL of an aqueous chlorine solution with an FAC concentration of 3600 mg / L prepared by electrolysis. The reaction between hypochlorite and bromide was allowed to proceed to completion, and the pH of the mixed halogen solution was then adjusted to 10.83. This solution had an ORP value of 657 mV. Three 200 mL samples of this solution were prepared and reacted with 0.25 g, 1.3 g, and 2.5 g of sodium sulfamate to produce sulfamate-stabilized halogen solutions. The pH, ORP, FAC content, FAB content, and total chlorine (TC) content of each solution were measured and are reported in the table below.

[0062] [Table 8] Example 9 A mixed halogen aqueous solution consisting of sodium hypochlorite and N-chlorosulfamate species was prepared by electrolysis of saturated sodium chloride brine containing sulfamic acid at a concentration of 50 g / L. The pH of this mixed halogen solution was found to be 11.15 and the TC concentration was 2475 mg / L. Four 200 mL samples of this solution were prepared and reacted with 0.101 g, 0.205 g, 0.410 g, and 2.043 g of sodium bromide to produce a series of mixed halogen solutions. The pH, FAC amount, and FAB amount of each solution were measured and are reported in the table below.

[0063] [Table 9] Example 10 A mixed halogen aqueous solution consisting of sodium hypochlorite and N-chlorosulfamate species was prepared by electrolysis of saturated sodium chloride brine containing sulfamic acid at a concentration of 100 g / L. The pH of this mixed halogen solution was found to be 11.03, with a TC concentration of 3725 mg / L. Four 200 mL samples of this solution were prepared and reacted with 0.116 g, 0.235 g, 0.469 g, and 2.337 g of sodium bromide to produce a series of mixed halogen solutions. The pH, FAC amount, and FAB amount of each solution were measured and are reported in the table below.

[0064] [Table 10] Example 11 An aqueous chlorine solution with a FAC concentration of 3625 mg / L was prepared by electrolysis. The ORP value of this solution was measured to be 804 mV and the pH was 8.96. Nine 200 mL samples of this solution were prepared and reacted with sodium bromide and sodium sulfamate dissolved in 20 mL of water before being added to the first aqueous chlorine solution. The pH, ORP, FAC content, FAB content, and total chlorine (TC) content of each solution were measured and are reported in the table below.

[0065] [Table 11] Thus, the present invention is well adapted to attain the objects and advantages described, as well as those inherent therein. The foregoing description is not intended to be limiting of the present invention, which may be used in different aspects or embodiments without departing from the scope of the present invention. The discussion of acts, steps, chemicals, devices, components, elements, and the like, is included herein solely for the purpose of providing a context for the present invention. No suggestion or implied that any such matter forms part of the prior art or is common general knowledge in the art to which the present invention pertains.

[0066] Moreover, the specific illustrative embodiments disclosed above can be altered or modified, and all such variations are deemed to be within the scope and spirit of the present invention. Although systems and methods are described as "comprising," "containing," or "including" various devices / components or steps, it will be understood that the systems and methods can also "consist essentially of" or "consist of" the various components and steps. Whenever a numerical range with a lower and upper limit is disclosed, every number within the range and every included range is expressly disclosed. In particular, each value range disclosed herein (in the form of "about a to about b," or similarly "approximately a to b") should be understood to describe each number and range within the broader value range. In the event of a conflict in the use of a word or term in this specification, the claims, and one or more patents or other documents incorporated herein by reference, the consistent definition in this specification shall control.

Claims

1. 1. A system for producing a mixed aqueous halogen solution having at least two distinct halogen species, comprising: a first storage tank configured to contain an aqueous halogen solution, the aqueous halogen solution being free of chlorine; a first mixing tank disposed downstream of the first storage tank, the first mixing tank including a flow obstruction structure; piping for transferring a stream of aqueous hypochlorite solution to the first mixing tank; a second storage tank containing the aqueous hypochlorite solution, the piping configured to transfer the aqueous hypochlorite solution from the second storage tank to the first mixing tank, the second storage tank being disposed upstream of the first mixing tank; a third storage tank for storing a pH adjusting chemical; a static mixer for mixing the aqueous hypochlorite solution with the pH adjusting chemical prior to delivery to the first mixing tank; a first sensor group including at least a pH sensor for measuring the pH of the pH-adjusted aqueous hypochlorite solution prior to transfer to the first mixing tank; a second sensor group disposed downstream of the first mixing tank, the second sensor group including one or more sensors for measuring one or more parameters of the mixed aqueous halogen solution; a control system connected to the first sensor group and the second sensor group, the control system controlling a first pump connected to the piping and the first storage tank, a second pump connected to the piping and the second storage tank, and a third pump connected to the piping and the third storage tank, respectively; Including, the system.

2. the flow disruption structure comprises one or more baffles; 2. The system of claim 1, wherein the baffle is configured to promote sufficient mixing of (a) the aqueous hypochlorite solution or the pH adjusted aqueous hypochlorite solution, and (b) the aqueous halogen solution without chlorine to produce the mixed aqueous halogen solution having at least two distinct halogen species.

3. 3. The system of claim 2, wherein the aqueous halogen solution is a bromine-containing fluid.

4. 2. The system of claim 1, wherein the aqueous halogen solution comprises bromine and iodine.

5. 2. The system of claim 1, wherein the parameter is selected from the group consisting of pH, oxidation-reduction potential (ORP), UV-Vis absorption profile, and combinations thereof.

6. 2. The system of claim 1, further comprising a fourth storage tank, said fourth storage tank fluidly connected to said second group of sensors, said fourth storage tank configured to contain a halogen stabilizing compound.

7. 7. The system of claim 6, further comprising piping for transporting said mixed aqueous halogen solution and said halogen stabilizing compound to a second mixing tank.

8. 8. The system of claim 7, wherein the second mixing tank includes one or more baffles, the baffles configured to promote sufficient mixing of (a) the mixed aqueous halogen solution and (b) the halogen stabilizing compound to produce a stabilized mixed aqueous halogen solution having at least two distinct halogen species.

9. 9. The system of claim 8, further comprising a fifth storage tank disposed downstream of said second mixing tank, said stabilized mixed aqueous halogen solution being delivered to said fifth storage tank.

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