U.S. patent application number 14/189632 was filed with the patent office on 2014-08-28 for corrosion inhibitors for cooling water applications.
This patent application is currently assigned to BAKER HUGHES INCORPORATED. The applicant listed for this patent is BAKER HUGHES INCORPORATED. Invention is credited to David N. Fulmer, Bing Bing Guo, Haiping Lu.
Application Number | 20140241939 14/189632 |
Document ID | / |
Family ID | 51388356 |
Filed Date | 2014-08-28 |
United States Patent
Application |
20140241939 |
Kind Code |
A1 |
Lu; Haiping ; et
al. |
August 28, 2014 |
CORROSION INHIBITORS FOR COOLING WATER APPLICATIONS
Abstract
A new corrosion inhibitor composition containing a carboxylic
acid and its water soluble salts with zinc can be used for
corrosion inhibition on the carbon steel pipe and heat exchangers
in industrial cooling water. This new composition of matter
contains less carboxylic acid and Zn.sup.2+ than previous
formulations and still have >90% corrosion inhibition. It is
disclosed that the synergistic effect of combining the carboxylic
acid with very small amounts of Zn results in a product with good
corrosion inhibition properties that is more environmentally
friendly than the current common phosphonate corrosion inhibitors;
particularly for use in cooling water applications.
Inventors: |
Lu; Haiping; (Sugar Land,
TX) ; Guo; Bing Bing; (Missouri City, TX) ;
Fulmer; David N.; (MIssouri City, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BAKER HUGHES INCORPORATED |
Houston |
TX |
US |
|
|
Assignee: |
BAKER HUGHES INCORPORATED
Houston
TX
|
Family ID: |
51388356 |
Appl. No.: |
14/189632 |
Filed: |
February 25, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61769601 |
Feb 26, 2013 |
|
|
|
Current U.S.
Class: |
422/5 ;
422/17 |
Current CPC
Class: |
C02F 2303/08 20130101;
C02F 2103/023 20130101; C23F 11/08 20130101; C02F 1/683
20130101 |
Class at
Publication: |
422/5 ;
422/17 |
International
Class: |
C23F 11/12 20060101
C23F011/12 |
Claims
1. A method for preventing or mitigating corrosion in cooling water
systems comprising treating the cooling water with an additive
comprising a soluble zinc salt and a soluble carboxylic acid
salt.
2. The method of claim 1 wherein the soluble zinc salt is selected
from the group consisting of: zinc chloride, zinc bromide, zinc
hydroxide, zinc carbonate, zinc borate, zinc nitrate, and
combinations thereof.
3. The method of claim 2 wherein the soluble zinc salt is selected
from the group consisting of: zinc chloride, zinc bromide, zinc
hydroxide and combinations thereof.
4. The method of claim 1 wherein the soluble carboxylic acid salt
is selected from the group consisting of a soluble gluconic acid
salt, a soluble saccharic acid salt, and combinations thereof.
5. The method of claim 1 wherein the additive, when added to
cooling water is present at a concentrations sufficient to provide
from about 30 to about 300 ppm by weight carboxylic acid or its
soluble salts.
6. The method of claim 5 wherein the additive, when added to
cooling water is present at a concentrations sufficient to provide
from about 30 to about 180 ppm by weight carboxylic acid or its
soluble salts.
7. The method of claim 1 wherein the additive, when added to
cooling water is present at a concentration sufficient to provide
up to 10 ppm by weight of soluble zinc salts.
8. The method of claim 1 wherein the additive, when added to
cooling water is present at a concentration sufficient to provide
up to 4 ppm by weight of soluble zinc salts.
9. The method of claim 1 wherein the additive additionally
comprises a composition selected from the group comprising: scale
inhibitors, yellow metal corrosion inhibitors, dispersants,
deodorants, biocides, dyes, and combinations thereof.
10. A method for preventing or mitigating corrosion in cooling
water comprising treating the cooling water with an additive
comprising a soluble zinc salt and a compound selected from the
group consisting of gluconic acid, saccharic acid, a water soluble
gluconate salt, a water soluble saccharic acid salt, and
combinations thereof.
11. The method of claim 9 wherein the water soluble saccharic acid
salt is selected from the group consisting of its potassium salts,
its calcium salts, and combinations thereof.
12. The method of claim 9 wherein the water soluble gluconate salt
is its sodium salt.
13. The method of claim 9 wherein the additive, when added to
cooling water is present at a concentrations sufficient to provide
from about 30 to about 300 ppm by weight of gluconic acid,
saccharic acid, a water soluble gluconate salt, a water soluble
saccharic acid salt, and combinations thereof.
14. The method of claim 12 wherein the additive, when added to
cooling water is present at a concentrations sufficient to provide
from about 30 to about 180 ppm by weight of gluconic acid,
saccharic acid, a water soluble gluconate salt, a water soluble
saccharic acid salt, and combinations thereof.
15. The method of claim 9 wherein the additive additionally
comprises a composition selected from the group comprising: scale
inhibitors, yellow metal corrosion inhibitors, dispersants,
deodorants, biocides, dyes, and combinations thereof.
16. A method for preventing or mitigating corrosion in a cooling
water system comprising treating the cooling water with an additive
comprising a soluble zinc carboxylate.
17. The method of claim 14 wherein the soluble zinc carboxylate is
present at a concentration of from 30 to about 300 ppm by
weight.
18. The method of claim 14 wherein the additive additionally
comprises a composition selected from the group comprising: scale
inhibitors, yellow metal corrosion inhibitors, dispersants,
deodorants, biocides, dyes, and combinations thereof.
19. A method for preventing or mitigating corrosion in cooling
water comprising treating the cooling water with an additive
comprising a compound selected from the group consisting of zinc
gluconate, the zinc salt of saccharic acid, and combinations
thereof.
20. The method of claim 16 wherein the additive additionally
comprises a composition selected from the group comprising: scale
inhibitors, yellow metal corrosion inhibitors, dispersants,
deodorants, biocides, dyes, and combinations thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional
patent application Ser. No. 61/769,601, filed on Feb. 26, 2013, the
entire disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to corrosion inhibitors. The
present invention particularly relates to corrosion inhibitors for
use in cooling water applications.
[0004] 2. Background of the Art
[0005] Corrosion may be a serious problem in industrial cooling
water applications. It causes many undesirable consequences,
including heat transfer reduction, increasing cleanings, equipment
repairs and replacements, and even unscheduled shutdowns. There are
numerous approaches to prevent corrosion in cooling water
applications. One of the most effective approaches is to use
chemicals to treat cooling water to inhibit the occurrence of
corrosion.
[0006] The common corrosion inhibitors include orthophosphate,
polyphosphates, phosphonates, molybdates, silicates, nitrites, etc.
Among these corrosion inhibitors, phosphorus based corrosion
inhibitors are widely used for carbon steel corrosion control in
cooling water applications because they have good cost
effectiveness and performance. However, cooling water is eventually
discharged into surface water, and there are more and more concerns
on the impact of phosphorus on the environment due to algal bloom.
Furthermore, the presence of phosphorus may react with the calcium
ions in cooling water to form calcium phosphate scale, which causes
the fouling and blocking of pipelines and heat transfer reductions.
Therefore, non-phosphorus (non-P) inhibitors are needed for
corrosion control in cooling water applications.
[0007] This invention discloses the art of novel, high performance
non-phosphorus chemical corrosion inhibition treatment program
which can be used in cooling water applications for preventing the
carbon steel corrosion. This treatment program is more
environmentally friendly than the current common phosphorus
corrosion inhibitors.
SUMMARY OF THE INVENTION
[0008] In one aspect, the invention is a method for preventing or
mitigating corrosion in cooling water comprising treating the
cooling water with an additive comprising a soluble zinc salt and a
soluble carboxylic acid salt.
[0009] In another aspect, the invention is a method for preventing
or mitigating corrosion in cooling water comprising treating the
cooling water with an additive comprising a soluble zinc salt and a
compound selected from the group consisting of gluconic acid,
saccharic acid, a water soluble gluconate salt, saccharic acid
salt, and combinations thereof.
[0010] In still another aspect, the invention is a method for
preventing or mitigating corrosion in cooling water comprising
treating the cooling water with an additive comprising a soluble
zinc carboxylate.
[0011] Another aspect of the invention is a method for preventing
or mitigating corrosion in cooling water comprising treating the
cooling water with an additive comprising a compound selected from
the group consisting of zinc gluconate, the salt of zinc and
saccharic acid, and combinations thereof.
[0012] Other compounds may also be included in the additives of
this application. For example, in addition to the zinc salts
already discussed above, scale inhibitors, yellow metal corrosion
inhibitors, such as tolyltriazole and benzotriazole, dispersants,
deodorants, biocides, and dyes may also be included in the
additives.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] For the purposes of this application, the term cooling water
is defined as water used for heat exchangers in commercial
processes such as chemical plants and refineries. Generally cooling
water streams will have a pH of from about 7.0 to 9.2. Often they
are buffered and sometimes have been treated to remove excessive
dissolved solids.
[0014] The composition of this invention may contain sufficient
amounts of each of the components to provide, when added to cooling
water: 30-300 parts per million (ppm) by weight carboxylic acid or
its soluble salts; and up to 10 ppm by weight of soluble zinc
salts. In one embodiment the additive may include: 30-180 ppm by
weight carboxylic acid and its soluble salts and up to 4 ppm by
weight of soluble zinc salts.
[0015] In one aspect, the invention is a method for preventing or
mitigating corrosion in cooling water comprising treating the
cooling water with an additive comprising a soluble zinc salt and a
soluble carboxylic acid salt. In some embodiments, the soluble
carboxylic acid salt is a compound selected from the group
consisting of a soluble gluconic acid salt, a soluble saccharic
acid salt, and combinations thereof.
[0016] The soluble zinc salts may be any known to those of ordinary
skill in the art to be both soluble and free from counter ions that
may be problematic in cooling water. For example, zinc chloride and
zinc bromide and even zinc hydroxide may be used while zinc
phosphate would be undesirable. Other salts that may be used with
the method of the application include, but are not limited to zinc
carbonate, zinc borate, zinc nitrate, and combinations thereof.
Hydrates may also be used, particularly where the hydrate may be
soluble while the unhydrated salt is not.
[0017] The additive of the application may be a zinc carboxylate
salt or it may be the product of admixing a first salt and a second
salt with the first salt being a soluble zinc salt and the second
salt being a soluble carboxylic acid salt. In one embodiment, the
zinc salt is selected from the group consisting of a soluble
gluconic acid salt, a soluble saccharic acid salt, and combinations
thereof.
[0018] The additives in the application may include other
compounds. For example, in addition to the zinc salts already
discussed above, yellow metal corrosion inhibitor such as
tolyltriazole or benzotriazole, scale dispersants, deodorants,
biocides, dyes, may also be included in the additives.
The Carboxylic Acid(s)
[0019] The carboxylic acid component of the additive may be
selected from the group consisting of gluconic acid and saccharic
acid, and other carboxylic acids and their derived polycarboxylic
acids, as well as their water soluble salts. In one embodiment,
gluconic acid and its sodium salt, saccharic acid and its potassium
and calcium salts are used to prepare the additives of the method
of the disclosure.
Zinc
[0020] The additives useful with the method of the disclosure may,
in one embodiment, be prepared using zinc chloride. In other
embodiments, the water soluble zinc salts may be selected from the
group consisting of zinc sulfate and zinc oxide.
[0021] The additive may be prepared using any methods known to
those of ordinary skill in the art of preparing zinc salts and
admixtures comprising zinc salts. Hydrates may be used, especially
where a salt would otherwise be insoluble or difficult to
handle.
[0022] While not wishing to be bound by any theory, it is
nevertheless believed that the carboxylic acids useful with the
method of the application are those that do not coordinate too
strongly with the zinc. For example gluconic acid, a
mono-carboxylic acid and saccharic acid, a dicarboxylic acid may
both be used with the method of the application and are very
efficient for preventing corrosion. In contrast however, butane
tetracarboxylic acid and malic acid, a four functional and two
functional acid respectively, show corrosion inhibition
performance, but higher dosage are needed to obtain same inhibition
efficiency than those of gluconic acid and saccharic acid.
EXAMPLES
[0023] The following examples are provided to illustrate the
present invention. The examples are not intended to limit the scope
of the claims and they should not be so interpreted. Amounts are in
weight parts or weight percentages unless otherwise indicated.
Examples 1-30
[0024] The composition of a cooling water sample shown in Table 1
is treated according to the conditions set forth in Table 2. Carbon
steel 1010 (CS 1010) coupons are used and corrosion is determined
by using the technique of linear polarization resistance. Chemical
concentrations used are expressed in parts per million (ppm). The
unit of corrosion rate is in mils per year (mpy). The inhibition
efficiency in Table 2 was calculated by equation (1)
Inhibition Efficiency = ( Corrosion Rate Blank - Corrosion rate
Dosage Corrosion Rate Blank ) .times. 100 % ( 1 ) ##EQU00001##
where Corrosion Rate.sub.Blank is the corrosion rate without any
additions of chemical treatments, Corrosion rate.sub.Dosage is the
corrosion rate with specific dosages of chemicals.
Comments Regarding the Examples
[0025] The combination of zinc with gluconate and saccharate salts
were very efficient, needing only 60 or fewer parts per million to
reduce 90% of the corrosion rate of carbon steel coupon observed in
the blanks. The gluconic acid is a monocarboxylic acid. The
saccharic acid is a dicarboxylic acid but it has a hydroxyl group
on every carbon between the acid groups which hinders free rotation
about the axis of the two acidic groups. More tests with other
compounds, such as either di- or higher functional acids, or the
compounds included other groups such as amino groups, showed
inhibition performance with higher or even much dosages to reach
90% corrosion inhibition.
TABLE-US-00001 TABLE 1 Na+ (ppm) 273 Ca2+ (ppm) 200 Mg2+ (ppm) 50
Fe2+ (ppm) 0.5 HCO3- (ppm) 100 Cl- (ppm) 500 SO42- (ppm) 496
TABLE-US-00002 TABLE 2 Butane- Poly- Citric Tartaric Sodium tetra-
Saccharic Malic Glycolic Erythorbic aspartic Corr. Acid Acid
Gluconate carboxylic Acid Acid acid acid acid Zn.sup.2+ Rate
Inhibition Example (ppm) (ppm) (ppm) acid(ppm) (ppm) (ppm) (ppm)
(ppm) (ppm) (ppm) (mpy) Efficiency 1 0 0 0 0 0 0 0 0 0 0 27 N/A 2 0
0 0 0 0 0 0 0 0 2 30 N/A 3 60 19.2 28.9 4 60 2 15.9 41.1 5 180 2
1.49 94.5 6 120 2 9.19 66.0 7 30 30 2 7.47 72.3 8 60 23.9 11.5 9 60
60 14 48.1 10 60 2 8.8 67.4 11 120 2 2.78 89.7 12 30 60 2 1.03 96.2
13 30 30 2 3.87 85.7 14 180 60 10.8 60.0 15 180 2 0.94 96.5 16 60
60 23.4 13.3 17 30 2 3.04 88.7 18 180 7.09 73.7 19 60 2 1.5 94.4 20
60 15.9 41.1 21 60 2 15 44.4 22 60 4.88 81.9 23 60 2 0.73 97.3 24
180 1.73 93.6 25 60 2 10.4 61.5 26 180 2 6.82 74.7 27 60 2 16.4
39.3 28 60 2 10.4 61.5 29 180 2 3.78 86.0 30 60 2 8.64 68.0
* * * * *