CROSS REFERENCE TO RELATED APPLICATION
[001] This application is a continuation-in-part of U.S. Serial No. 11/618,227, which is herein
incorporated by reference.
COPYRIGHT NOTICE
[002] A portion of the disclosure of this patent docmnent contains or may contain copyright
protected material. The copyright owner has no objection to the photocopy reproduction
by anyone of the patent document or the patent disclosure in exactly the form it appears in
the Patent and Trademaiic OfHce patent file or records, but otherwise reserves all
copjright rights whatsoever.
TECHNICAL FIELD
[003] This invention relates to the production of stable chloramine for use as a biocidal
composition. The invention shows the method for production of chloramine in a stable
form that allows for the production, storage and transportation of chloramine. The
invention demonstrates the method of producing a stable and fimctional chloramine,
which allows for the use of chloramines in water treatment systems, and a wide variety of
other treatment systems, as biocidal composition without its rapid degradation.
BACKGROUND
[004] The invention described here pertains to the production of a biofouling control agent.
The basis for the invention is the composition of the reactants and the conditions for
production using concentrated reactants to convert two liquid solutions from their native
chemical form to another with altered biocidal properties.
[005] Throughout the world, there are many different types of industrial water systems.
Industrial water systems exist so that necessary chemical, mechanical and biological
processes can be conducted to reach the desired outcome. Fouling can occur even in
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industrial water systems treated with the best water treatment programs currently
available. For purposes of this patent application "fouling" is defined as "the deposition
of any organic or inorganic material on a surface".
[006] If these iadustrial water systems are not treated for microbial fouling control, then they
will become heavily fouled. Fouling has a negative impact on the industrial water system.
For example, severe mineral scale (inorganic material) can buildup on the water contact
siufaces and anywhere there is scale, there is an ideal environment for the growth of
microorganisms.
[007] Fouling occurs by a variety of mechanisms including deposition of air-borne and waterborne
and water-formed contaminants, water stagnation, process leaks, and other factors.
If allowed to progress, the system can suffer fixim decreased operational efSciency,
premature equipment failure, loss in productivity, loss in product quality, and increased
heal£h-related risks associated with microbial fouling.
[008] Fouling can also occur due to microbiological contamination. Sources of microbial
contamination in industrial water systems are numerous and may include, but are not
limited to, air-borne contamination, water make-up, process leaks and improperly cleaned
equipment. These microorganisms can rapidly establish microbial communities on any
wetted or semi-wetted sur&ce of the water system. Once these microbial populations are
present in the bulk water more than 99% of the microbes present in the water will be
present on the surfoce in the form of biofilms.
[009] Exopolymeric subsstance secreted firom tiie microorganisms aid in the formation of
biofilms as the microbial communities develop on the sur&ce. These biofilms are
complex ecosystems that establish a means for concentrating nutrients and offer
protection for growth. Biofilms can accelerate scale, corrosion, and other fouling
processes. Not only do biofilms contribute to reduction of system efficiencies, but they
also provide an excellent environment for microbial proliferation that can mclude
pathogenic bacteria. It is therefore important that biofilms and other fouling processes be
reduced to the greatest extent possible to maximize process efficiency and minimize the
health-related risks from water-borne pathogens.
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[0010] Several factors contribute to tbe problem of biological fouling and govern its extent.
Water temperature; water pH; organic and inorganic nutrients, growth conditions such as
aerobic or anaerobic conditions, and in some cases the presence or absence of sunlight,
etc. can play an important role. These factors also help in deciding what types of
microorganisms might be present in the water system.
[0011] As described earlier, biological fouling can cause unwanted process interferences and
therefore must be controlled. Many different approaches are utilized for the control of
biological fouling in industrial processes. Ibe most commonly used method is the
application of biocidal compounds to the process waters. The biocides applied may be
oxidizing or non-oxidizing in nature. Due to several different factors such as economics
and environmental concerns, the oxidizing biocides are preferred. Oxidizing biocides
such as chlorine gas, hypochlorous acid, bromine derived biocides, and other oxidizing
biocides are widely used in the treatment of industrial water sj^tems.
[0012] One factor in establishing the efficacy of oxidizing biocides is the presence of
components within the water matrix that would constitute a "chlorine demand" or
oxidizing biocide demand. "Chlorine demand" is defined as the quantity of chlorine that
is reduced or otherwise transformed to inert forms of chlorine by substances in the water.
Chlorine-consuming substances include, but are not limited to, microorganisms, organic
molecules, anmionia and amino derivatives; sulfides, cyanides, oxidizable cations, pulp
lignins, starch, sugars, oil, water treatment additives like scale and corrosion inhibitors,
etc. Microbial growth in die water and in biofilms contributes to the chlorine demand of
the water and to the chlorine demand of the system to be treated. Conventional oxidizing
biocides were found to be ineffective in waters containing a high chlorine demand,
including heavy slimes. Non-oxidizing biocides are usually recommended for such
waters.
[0013] Chloramines are effective and are typically used in conditions where a high demand for
oxidizing biocides such as chlorine exists or under conditions that benefit from the
persistence of an 'oxidizing' biocide. Domestic water systems are increasingly being
treated wifli chloramines. Chloramines are generally formed when firee chlorine reacts
with anmionia present or added to the waters. Many different methods for production of
chloramines have been documented. Certain key parameters of the reaction between the
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chlorine and the nitrogen source determine the stability, and efScacy of the produced
biocidal compound. The previously described methods have relied on either the preformation
of dilute solutions of the reactants followed by their combination to produce a
solution of chloramines. The reactants are an amine source in the form of an ammonium
salt (sulfate, bromide, or chloride) and a Cl-donor (chlorine donor) in the form of gas or
combined with alkaU earth metal (Na or Ca). Also, the described methods have relied on
controlling the pH of tiie reaction mix by the addition of a reactant at a high pH or by the
separate addition of a caustic solution. The disinfectant thus produced must be
immediately fed into the system being treated since the disinfectant degrades rapidly.
The disinfectant solution is generated outside the system being treated and then fed into
the aqueous system for treatment. In previously described methods of production for
treatment of liquids to control biological fouling, a sigoificant problem occurred in that
the active biocidal ingredient was unstable chemically and rapidly decomposed with a
resulting &st drop in pH. This rapid deterioration of the biocidal ingredient resulted in a
loss in efScacy. It was also observed that the pH of the active biocidal ingredient was
never >8.0 due to the rapid decomposition of the biocidal component (referenced in
US5976386). In yet other methods where chloramine was produced as a precursor in the
production of hydrazine, concentrations above 3.5% were never achieved due to the
presence of hydroxyl ions in the initial reaction mixture (referenced in US3254952).
SUMMARY
[0014] The current invention describes the following key aspects:
1. A composition of the reactants for production of a "more stable" disinfectant
solution,
2. Conditions for the production of a "more stable" form of the biocidal component,
and
3. A process for the production of the disinfectant.
DETAILED DESCRIPTION
[0015] The invention relates to a method for producing a stable chloramine wherein a
concentrated chlorine source is combined with a concentrated amine source and is
agitated to produce a stable chloramine with a pH above 5. The chlorine source of the
invention contains an alkali earth metal hydroxide where flie preferred source of the
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chlorine is sodium hypochlorite or calcium hypochlorite and the amine source is
preferably ammooium sul&te (NH4)2S04, or ammomum hydroxide NH4OH.
[0016] The method of the invention includes a reaction mediimi where the reaction of flie
Chlorine source and the amine source occurs to form the chloramine. The reaction
medium is a liquid that is preferably water. The product of the invention is stable
chloramine.
[0017] The invention details a method for producing a stable chloramine wherein a concentrated
Chlorine source is combined with a concentrated amine source with a reaction medium
and is agitated to produce a stable chloramine with a pH of 7 or above.
EXAMPLES
[0018] The foregoing may be better understood by reference to the following example, which is
intended to illustrate methods for carrying out the invention and is not intended to limit
the scope of the invention.
EXAMPLE 1
[0019] In an experiment to imderstand the production and stability of the chloramine solution
produced, &esh solutions of hypochlorite, (NH4}2S04, and NH4OH were prepared and
used for the production of chloramine. The prepared hypochlorite solution was tested
separately and was foimd to contain-^llO ppm as fiee CI2, as expected from dilutions.
The amount of chloramine produced was evaluated by measuring the Free CI2 and Total
CI2 of the product. Results &om the experiment showed that 100% conversion to
chloramine (Total CI2) was observed. In addition, the pH of the product produced with
(NH4)2S04, and NH4OH remained above 7.
[0020] The chloramine solution produced was kept in Has dark and reanalyzed after 1 day. Free
CI2 and Total CI2 was measured again to understand the stability of the chloramine
solution, produced and maintained in a closed space of a 50 ml tube. The data was
compared to the production time data and loss in Total CI2 level was a measure of the loss
of chloramine &om the solution. The chloramine products produced with amine derived
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from (NH4)2S04, or NH4OH showed only slight degradation, 7.7% and 5.9%,
respectively, after 1 day. As an observation, the chloramine solution produced with
amine derived from Ammonium Bromide (NRfBr) showed more than 90%
loss/degradation after 1 day.
[0021] It should be understood that various changes and modifications to the presently preferred
embodiments described herein will be apparent to those skilled in the art. Such changes
and modifications can be made without departing from the spirit and scope of the
invention and without diminishing its intended advantages. It is therefore intended that
such changes and modifications be covered by the appended claims.

We Claim:
1. A method for producing a stable chloiamine in a continuous flow wherein a concentrated
chlorine source is combined at ambient temperature with a concentrated amine source at ambient
temperature and is agitated to produce a stable chloramine with a pH of 7 to 10.5.
2. The method of claim I wherein the chlorine source contains an alkali earth metal
hydroxide.
3. The method of claim 1 wherein the amine source is ammonium sulfate.
4. The method of claim 1 wherein the amine source is ammonium hydroxide.
5. The method of claim 1 molar ratio of chlorine source to amine source is 1:0.755 to 1:6
and more preferably 1:0.755 to 1:2.
6. The method of claim 1 molar ratio of chlorine source to amine source is 1:0.755 to 1:2.
7. The method of claim 6 wherein the reaction medium is a liquid.
8. The method of claim 6 wherein hydroxide levels are increased.
9. The method of claim 1 wherein the stable chloramine has a pH of 8 to 10.
10. The method of claim 2 wherein the chlorine source is sodium hypochlorite or calcitun
hypochlorite.
11. A method for producing a stable chloramine wherein a concentrated chlorine source is
combined with a concentrated amine source with a reaction medium and is agitated to produce a
stable chloramine with a pH of 7 to 10.5.
12. The method of claim 11 wherein the chlorine source contains an alkali earth metal
hydroxide.
13. The method of claim 12 wherein the chlorine source is sodium hypochlorite or calcium
hypochlorite.
14. The method of claim 11 wherein the amine source is ammonium sulfate.
15. The method of claim 11 wherein the amine source is ammonium hydroxide.
Dated this 13th day of January 2012.