Methods and apparatus for controlling the production of halogenamine biocides

Abstract

The present invention provides a method and apparatus for controlling the production of a haloamine biocide based on a direct, in-process measurement of oxidant content to produce the desired haloamine biocide for controlling microbial growth in an aqueous system, particularly in an industrial water system.

Description

Technical Field

[0001] Generally speaking, the present disclosure relates to methods for controlling the production of haloamine biocides that control the growth of microorganisms in aqueous systems, particularly industrial water systems, based on direct, in-process measurement of hypohalite reagent active content. Background Art

[0002] Optimal use of haloamine microbial agents in industrial aqueous systems depends in part on achieving a stoichiometric reaction of the amine solution with the hypohalite solution.

[0003] Oversupply of hypohalite reagents such as sodium hypochlorite can lead to breakpoint degradation of the desired active ("Chloramine Production & Monitoring in Florida's Water Supply Systems", McVay, Robert D., Florida Water Resources Journal, April 2009, pp. 16-26).

[0004] Insufficient supply of hypohalite reagents, besides being not optimized from an economic point of view, can also lead to the addition of ammonia species to the water system, depending on the amine solution used, as well as other problems arising. For example, in systems containing copper alloy metallurgy, corrosion processes can be increased.

[0005] One challenge in developing methods to achieve stoichiometric reaction ratios is to compensate for the degradation rate of the hypochlorite reagent solution. A common commercial grade hypochlorite reagent used to produce haloamines is approximately 12.5% ​​by weight sodium hypochlorite. It is estimated that after 10 days of storage at 80°F, the active content of the solution will decrease to about 11%, and the decomposition rate increases significantly at higher storage temperatures. Please refer to "Sodium Hypochlorite-Product Stewardship Manual" (Olin Corporation, Form No. 102-00553-0619PI, 2019).

[0006] Various methods have been used to prevent problems associated with decomposition of hypohalite solutions, including simultaneous mixing of hypochlorite solutions with amine sources including ammonium bromide to produce haloamine biocide solutions. The feed rate of the reagents is monitored and controlled by measuring the pH of the resulting biocide solution. However, this is a dependent reactive variable and active control of the haloamine biocide being produced is continually required.

[0007] Other methods for producing biocides include mixing a hypochlorite oxidant solution with an ammonium salt solution; and monitoring a control parameter indicating when a maximum yield of the biocide has been achieved, and wherein the control parameter is not pH. The control parameter is a parameter selected from oxidation-reduction potential (ORP), conductivity, induction, and oxygen saturation to optimize the ratio between the oxidant and the amine. However, these methods are reactive in nature and inefficient in terms of chemical usage.

[0008] Some methods describe the production of halogenated amine biocides containing a blend of amine monochloride (MCA) and amine dichloride (DCA) by first adding the concentrated amines to a storage tank and diluting to the desired concentration, adding the desired amount of a halogen source to the tank and adjusting the pH to a predetermined value to convert a portion of the MCA to DCA.

[0009] Other methods teach the use of temperature differentials to monitor and control exothermic or endothermic chemical reactions. An increase in the temperature of a reaction mixture that exceeds the expected temperature of a desired reaction, such as the reaction of sodium hypochlorite with ammonia to form MCA, can be detected and used to generate a signal that can be used to adjust the flow or shut down one or more chemical feed devices. This is another reactive process and regulation after the production of haloamine biocides.

[0010] Still other known methods describe asynchronous feeding of reagents to form chloroamine biocidal compositions, the reagents including an amine source of disinfectant in concentrated form, an oxidizing halogen in concentrated form, and a diluent. Parameters used to adjust the reagent flow include volume measurements, ORP, residual chlorine, pH, temperature, and microbial activity. Again, these are all reactive methods and rely on monitoring, obtaining test results, and then making any necessary adjustments to the method.

[0011] All of the above methods involve compensating the reagent feed based on properties associated with the produced biocide solution and are reactive methods. Furthermore, the practicality of these methods appears to depend in part on the choice of amine source and reaction conditions such as starting pH and make-up water chemistry.

[0012] Furthermore, other desirable features and characteristics of the present disclosure will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background. Summary of the invention

[0013] A method for producing a haloamine biocide based on direct, in-process measurement of hypohalite reagent actives is provided. The method involves directly measuring oxidant concentration, inputting or otherwise recording information into a programmable logic controller (PLC) along with an amine concentration delivered on-site and a predetermined or desired active of the haloamine biocide being produced. Based on the measured oxidant concentration, amine concentration, and the predetermined active of the haloamine biocide being produced, the PLC calculates and controls the required amounts of water, oxidant, and amine necessary to achieve the predetermined or desired haloamine biocide concentration.

[0014] In addition, a device for directly preparing a halogenated amine biocide with a predetermined or desired active substance online is provided. The device includes means (means, mode) such as a pump for delivering water, an oxidant and an amine to an addition point, where the oxidant contacts the amine to produce a halogenated amine biocide with a desired active substance. The device includes a probe for directly measuring the concentration of the oxidant, wherein the oxidant concentration is fed into a programmable logic controller (PLC) together with the concentration of the amine reagent and the predetermined or desired active substance of the produced halogenated amine biocide. Based on the information entered in the PLC, the PLC controls the amount of chemicals delivered by the chemical stream. For example, a pump P1 capable of delivering a controlled amount of water, a pump P2 capable of delivering a controlled amount of an oxidant, and a pump P3 capable of delivering a controlled amount of an amine reagent are connected and independently controlled by the PLC. Based on the measured and entered information, the PLC controls the amount of water, oxidant and amine that react together, thereby producing a halogenated amine biocide with a predetermined or desired active substance.

[0015] Finally, a method for controlling microbial growth in an aqueous system is provided. The method includes providing water, an oxidant, and an amine source, wherein the oxidant concentration is measured online before the oxidant is combined with the amine. The oxidant concentration is input or otherwise entered into a programmable logic controller (PLC) along with the on-site delivered or pure amine concentration and the predetermined or desired active of the produced haloamine biocide. Based on the measured oxidant concentration, amine concentration, and desired active, the PLC calculates and controls the amount of water, oxidant, and amine required to produce the haloamine biocide with the desired or predetermined active. The haloamine biocide is then added to the aqueous system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention is described below in conjunction with the accompanying drawings, in which:

[0017] Figure 1 is a schematic diagram of a control scheme for the process of the present invention wherein the hypohalite solution and the amine reagent are pre-diluted prior to mixing to form the haloamine biocide solution.

[0018] Figure 2 is a schematic diagram of a control scheme for the process of the present invention, wherein a hypohalite solution and an amine reagent are mixed in-line to form a haloamine biocide solution. DETAILED DESCRIPTION

[0019] The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or its application and uses. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

[0020] For the purpose of the present method, haloamine is defined as a chemical having a composition comprising one or more halogen atoms associated with an amine group and having antimicrobial activity. Nitrogen may or may not be connected to another atom other than hydrogen. Halogen atoms include chlorine, bromine, iodine and fluorine. Any haloamine can be used in the method described herein to treat industrial process water. Preferably, the haloamine is a chloroamine.

[0021] The method of the present invention teaches an oxidant concentration dependent method wherein the amount of amine required to produce the desired haloamine biocide is delivered based on a predetermined oxidant concentration, which provides a more efficient method that is an active method rather than a passive method.

[0022] The devices and methods described herein can be used to produce microbicidal mixtures or combinations of halogenated amines having high antimicrobial activity.

[0023] In one aspect of the inventive method, water, an oxidant, and an amine source are combined in a direct in-line process to produce a haloamine biocide having a predetermined or desired active. In particular, a probe is provided for directly measuring the oxidant concentration, which is entered or otherwise input into a programmable logic controller (PLC). In addition to the oxidant concentration, the amine reagent concentration, the desired active of the haloamine biocide, is also entered or otherwise input into the PLC. Based on this information, the PLC independently controls measures such as pumps for controlling the amount of water, oxidant, and amine delivered to the addition point for producing the haloamine biocide.

[0024] In some aspects of the methods of the invention, dilution with water is used prior to combining the oxidizing agent and / or the amine to produce the haloamine biocide.

[0025] In other aspects of the method of the present invention, the haloamine comprises one or more halogen atoms associated with an amine group and has antimicrobial activity. Preferably, the halogen atom is selected from chlorine, bromine, iodine and fluorine, and the haloamine may be a chloroamine.

[0026] In other aspects of the method, the pH of the resulting haloamine can be further adjusted to convert a portion of the haloamine from a monohaloamine to a dihaloamine.

[0027] In other aspects of the present method, the amine source or reagent can be, but is not limited to, ammonia and ammonium salts and compounds containing primary and secondary amine functional groups. 4 + Those salts of cations and related anions. Examples of ammonium salts include, but are not limited to, ammonium acetate, ammonium bicarbonate, ammonium difluoride, ammonium bromide, ammonium carbamate, ammonium carbonate, ammonium chloride, ammonium citrate, ammonium fluoride, ammonium hydroxide, ammonium iodide, ammonium molybdate, ammonium nitrate, ammonium oxalate, ammonium persulfate, ammonium phosphate, ammonium sulfate, ammonium sulfide, ferric ammonium sulfate, ferrous ammonium sulfate, and aminosulfonic acid. Preferred ammonium salts are ammonium bicarbonate, ammonium carbamate, ammonium carbonate, ammonium chloride, ammonium hydroxide, ammonium sulfate, aminosulfonic acid, and mixtures thereof.

[0028] In some aspects of the method, the oxidant that can be used to react with amine to produce haloamine may include but is not limited to chlorine, hypochlorite, hypochlorous acid, chlorine dioxide, chlorinated isocyanurate, bromine, hypobromite, hypobromous acid, bromine chloride, halogenated hydantoin, ozone and peroxy compounds such as perborate, percarbonate, persulfate, hydrogen peroxide, percarboxylic acid and peracetic acid. Preferred are hypohalites, including hypochlorite and hypobromite, and most preferred is sodium hypochlorite.

[0029] In one aspect of the method of the present invention, the amine source is ammonium sulfate and the oxidizing agent is sodium hypochlorite, wherein the resulting haloamine biocide is monochloroamine (MCA) or a synergistic combination thereof with dichloroamine (MCA / DCA).

[0030] In other aspects of the method of the present invention, the oxidant is selected from chlorine, hypohalite, hypochlorous acid, chlorine dioxide, chlorinated isocyanurate, bromine, hypobromite, hypobromous acid, bromine chloride, halogenated hydantoin and combinations thereof. Preferably, the hypohalite is selected from sodium hypochlorite and hypobromite.

[0031] In other aspects of the method, the haloamine biocide produced has an active chlorine content of about 1,000 to about 10,000 ppm and may have an active chlorine content of about 3,000 to about 8,000 ppm.

[0032] In one aspect of the method, sodium hypochlorite and an amine reagent are fed into the apparatus as concentrated solutions. TM CX3125 microbicide is a sodium hypochlorite solution (Solenis, LLC, Wilmington DE) with a nominal concentration of 12.5 wt %. TM CX3400 chlorine stabilizer is a 40 wt % ammonium sulfate solution (Solenis, LLC, Wilmington DE). These can be found in Figure 1 or Figure 2The halogenated amine biocide solution is reacted in water in a device of to produce a halogenated amine biocide solution having 1,000-10,000 ppm active matter (calculated as chlorine). Preferably, the biocide concentration is 3,000-8,000 ppm active matter (calculated as chlorine).

[0033] In some aspects of the present methods, the haloamine biocide can be produced with tight concentration tolerances and can be maintained as a fixed variable.

[0034] The present invention also provides Figure 1 and Figure 2 A method and apparatus for preparing a halogenated amine biocide is shown. The apparatus includes a probe for directly measuring the concentration of an oxidant being used in the preparation of the halogenated amine biocide. The measured oxidant concentration is input or otherwise entered into a programmable logic controller (PLC) along with the delivered amine concentration and the desired or predetermined active of the produced halogenated amine biocide. The PLC uses the entered oxidant concentration and automatically calculates the flow rate of the oxidant solution (pump P2) and the flow rate of the amine solution (pump P3) to produce a halogenated amine biocide with the desired active or concentration. The PLC can monitor the flow rates of all three components, including water (pump P1), to ensure that the correct concentration of chemicals is maintained to produce the desired halogenated amine biocide and that the apparatus operates as expected.

[0035] In other aspects of the apparatus, a pH probe may also be installed in the line of the generated haloamine biocide solution to check the quality of the biocide and allow the flow rate of the chemical to be adjusted if necessary to produce the desired product. For example, if a breakthrough decomposition of the haloamine is detected via a rapid decrease in pH, the PLC may be programmed to automatically shut down the reagent feed.

[0036] On the other hand, pH can be used to monitor the conversion of monochloroamine (MCA) to dichloroamine (DCA) to provide the desired concentration of haloamine biocide produced.

[0037] In other aspects of the apparatus of the present invention, the oxidant concentration may be very non-constant and may change rapidly under normal shipping and storage conditions. The PLC automatically compensates for changes in oxidant concentration to maintain the stoichiometric feeds of oxidant and amine. For example, the desired optimal stoichiometric feed of ammonium sulfate is two moles of bleach per mole of ammonium sulfate, respectively. The apparatus of the present invention is able to control the feed rates of the chemicals to maintain the proper ratio.

[0038] In other aspects, the apparatus of the present invention further comprises a conduit for diluting the oxidant and / or the amine reagent to a desired concentration before the oxidant and the amine reagent come into contact with each other.

[0039] In other aspects, the device also includes a pH probe capable of detecting a breakthrough point for halogenated amines or a point at which chlorine levels exceed the oxidant requirement. In theory, exceeding the "breakthrough point" would result in a reduction in the level of a desired disinfectant species, such as chloroamines.

[0040] In other aspects of the apparatus, instruments capable of measuring the concentration of the bleach solution in real time and providing a signal to be integrated into the PLC for controlling the reagent feed are suitable for use in the present method. An example of such an instrument and device is the ST-600 online bleach monitoring probe (Pyxis Labs, Inc., Holliston, MA). The probe determines the bleach concentration by measuring the optical density of the bleach solution using near ultraviolet light. An output current of 4 to 20 milliamperes (mA) to the PLC indicates 0 to 16 weight percent bleach.

[0041] Finally, a method for controlling microbial growth in an aqueous system is provided. The method includes providing water, an oxidant, and an amine source. The oxidant concentration is measured online before the oxidant is mixed with the amine and input or otherwise entered into a programmable logic controller (PLC). In addition, the on-site delivered or pure amine concentration and the predetermined or required active substance of the produced haloamine biocide are entered into the PLC. Based on the measured oxidant concentration, amine concentration, and required active substance, the PLC calculates and controls the amount of water, oxidant, and amine required to produce the haloamine biocide with the predetermined active substance. The haloamine biocide is then added to the aqueous system.

[0042] Example

[0043] The following examples are intended to illustrate the methods of the present invention for controlling the production of haloamines based on direct, in-process measurement of hypohalite reagent actives, but are not intended to limit the scope of the invention. These examples illustrate how the apparatus and methods described herein can be used to automatically adjust the reagent feed to produce a haloamine biocide solution. For example, depending on the application, it may be preferred to use a mixture of one or more amines; for example, ammonium bromide, ammonium carbamate, aminosulfonic acid and / or ammonium sulfate. If desired, the present invention can also be used to control the reagent feed to a substoichiometric amount.

[0044] Example 1

[0045] In several months of trials, Figure 2 The device described in the experiment was used to treat the Multi Hearth Furnace (MHF) cogeneration condenser cooling water system. During the test process, the feed device accurately adjusted the Biosperse TM CX3125 and BiosperseTM The pumping rate of the CX3400 reagent is adjusted to compensate for the changes experienced by the bleach concentration and the required amount of biocide is added to achieve 1.5-3.0 ppm of free chlorine in the return water. The plant is configured to produce monochloroamine (MCA) and to produce a blend of MCA and dichloroamine (DCA) by post-adjusting the pH of the MCA (lowered by adding acid). Using the present method, the addition of chemicals to the system is reduced to once a day, approximately 20 minutes to 40 minutes, compared to known methods (such as continuous hypochlorination / non-oxidizing biocide methods), while improving biological control and reducing copper metallurgical corrosion rates.

[0046] Example 2

[0047] In several months of trials, Figure 1 and Figure 2 The device was constructed to treat cooling water systems in chemical process industry (CPI) applications. During the test process, the device accurately regulated the Biosperse TM CX3125 and Biosperse TM The pumping flow rate of the CX3400 reagent is adjusted to compensate for the changes in bleach concentration experienced in the two configurations. The typical target feed is 2.5 ppm of free chlorine in the return water, added for about 20 minutes every 12 to 16 hours. Analysis of the MCA biocide solution discharged from the unit found that Biosperse TM CX3400 achieved greater than 93% conversion to desired products. The trial demonstrated that improvements in biofilm control translate into higher plant efficiency and lower operating costs compared to currently used biocide approaches.

[0048] Although at least one exemplary embodiment has been given in the foregoing detailed description, it should be understood that there are a large number of variations. It should also be understood that the at least one exemplary embodiment is only an example and is not intended to limit the scope, applicability or configuration of the present disclosure in any way. On the contrary, the foregoing detailed description will provide a convenient roadmap for implementing the exemplary embodiments of the present disclosure to those skilled in the art. It should be understood that, without departing from the scope of the present disclosure as set forth in the appended claims, various changes may be made to the functions and arrangements of the elements described in the exemplary embodiments.

Claims

1. A method for producing a haloamine biocide having a desired active substance, which comprises: a) providing water, an oxidizing agent and an amine of a known concentration; and b) wherein the concentration of the oxidizing agent is measured in real time to determine the required amount of the oxidizing agent; wherein the required amount of the oxidizing agent is fed into a programmable logic controller, wherein the known amine concentration has been entered into the controller, and wherein based on the required amount of the oxidizing agent in real time and the known amine concentration, the programmable logic controller calculates the amounts of water, oxidizing agent and amine required to produce the haloamine biocide having the desired active substance; c) combining water, oxidizing agent and amine in the amounts calculated by the programmable logic controller to produce the haloamine biocide having the desired active substance; and d) adjusting the pH of the haloamine biocide solution to convert a portion of the haloamine from a mono-haloamine to a di-haloamine.

2. The method according to claim 1, wherein the oxidizing agent and / or the amine is diluted with water before combining the oxidizing agent and the amine.

3. The method according to claim 1, which further comprises measuring the pH of the haloamine biocide and adjusting the pH of the haloamine biocide solution to convert a portion of the haloamine from a mono-haloamine to a di-haloamine.

4. The method according to claim 1, wherein the amine is selected from ammonia and ammonium salts and compounds containing primary and secondary amine functional groups.

5. The method according to claim 4, wherein the ammonium salt is selected from ammonium acetate, ammonium bicarbonate, ammonium bifluoride, ammonium bromide, ammonium carbamate, ammonium carbonate, ammonium chloride, ammonium citrate, ammonium fluoride, ammonium hydroxide, ammonium iodide, ammonium molybdate, ammonium nitrate, ammonium oxalate, ammonium persulfate, ammonium phosphate, ammonium sulfate, ammonium sulfide, ammonium iron sulfate, ammonium ferrous sulfate, ammonium sulfamate and combinations thereof.

6. The method according to claim 1, wherein the oxidizing agent is selected from chlorine, hypohalite, hypochlorous acid, chlorine dioxide, chlorinated isocyanurate, bromine, hypobromite, hypobromous acid, bromine chloride, haloacetohydantoin and combinations thereof.

7. The method according to any one of claims 1-6, wherein the active chlorine of the produced haloamine is 1,000 to 10,000 ppm.

8. An apparatus for directly and on-line preparing a haloamine biocide having a desired active substance, which comprises: a) a probe for directly measuring the concentration of the oxidizing agent, b) a programmable logic controller, wherein the measured oxidizing agent concentration, the known or determined amine reagent concentration and the desired active substance of the produced haloamine biocide are entered into the programmable logic controller, and the programmable logic controller is capable of calculating the amounts of water, oxidizing agent and amine required to produce the haloamine biocide having the desired active substance; c) a pump P1 capable of delivering a controlled amount of water; d) a pump P2 capable of delivering a controlled amount of the oxidizing agent; and e) a pump P3 capable of delivering a controlled amount of the amine reagent; wherein water, oxidizing agent and amine are combined to produce a haloamine biocide having the desired active substance; and f) a pH probe capable of detecting the breakthrough point of the haloamine biocide.

9. The apparatus according to claim 8, further comprising a conduit for diluting the oxidant and / or the amine reagent to a desired concentration before the oxidant and the amine reagent come into contact with each other.

10. A method for controlling microbial growth in an aqueous system using a haloamine biocide based on the direct, on-line measurement of the content of the hypohalite reagent active substance, which comprises: a. providing water, an oxidant, and an amine; wherein, based on the required amount of the oxidant determined from the concentration of the oxidant measured in real time on-line and the known or determined amine concentration, a programmable logic controller calculates and controls the amounts of water, oxidant, and amine required to produce a haloamine biocide having a desired content of the hypohalite reagent active substance; b. combining water, the oxidant at a determined concentration, and the amine at a known or determined concentration in the amounts calculated by the programmable logic controller to produce a haloamine biocide having a desired hypohalite reagent active substance; and c. adding the produced haloamine biocide to the aqueous system; d. detecting whether the chlorine level exceeds the required amount of the oxidant; e. automatically adjusting the amounts of water, the oxidant at a determined concentration, and / or the amine at a known or determined concentration added to the aqueous system if it is determined that the chlorine level exceeds the required amount of the oxidant by a rapid decrease in pH; and f. adjusting the pH of the haloamine biocide solution to convert a portion of the haloamine from a mono-haloamine to a di-haloamine.

11. The method according to claim 10, wherein the oxidant and / or the amine is diluted with water before combining the oxidant at the determined concentration and the amine at a known or determined concentration.

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