CA2074609A1 - Inhibition of scale formation by polyepoxysuccinic acid - Google Patents
Inhibition of scale formation by polyepoxysuccinic acidInfo
- Publication number
- CA2074609A1 CA2074609A1 CA 2074609 CA2074609A CA2074609A1 CA 2074609 A1 CA2074609 A1 CA 2074609A1 CA 2074609 CA2074609 CA 2074609 CA 2074609 A CA2074609 A CA 2074609A CA 2074609 A1 CA2074609 A1 CA 2074609A1
- Authority
- CA
- Canada
- Prior art keywords
- ppm
- scale
- acid
- calcium
- added
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Landscapes
- Preventing Corrosion Or Incrustation Of Metals (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
ABSTRACT OF THE INVENTION
A method for inhibiting or preventing the formation of scale on surfaces in contact with an aqueous system comprising adding to the system a polyepoxysuccinic acid having the formula
A method for inhibiting or preventing the formation of scale on surfaces in contact with an aqueous system comprising adding to the system a polyepoxysuccinic acid having the formula
Description
--2 ~ !7 FIELD OF THE INVENTION
This invention relates to a method for inhibiting or prevenking the formation of scale on surfaces which are in contact with an aqueous system and more specifically to a method wherein a polyepoxysuccinic acid is added to the system in an amount effective to inhibit the formation of scale.
BA(~KGROUND OF THE I~7ENTION
Most industrial aqueous systems contain alkaline earth metal cation, such as calcium, magnesium and the like as well as numerous anions such as bicarbonate, carbonate, sulfate, and the like. When the concentration of the various combinations of cation and anions exceed the solubility of their reaction products, precipitates tend to form until the product solubility concentrations are no longer exceeded. As these reaction products precipitate on the surfaces of the aqueous systems, the form what is known as scale. The precipitation of calcium carbonate is by far the most common form of scale in industrial aqueous systems. This occurs when the ionic product of calcium and carbonate exceeds the solubility of the calcium carbonate and a solid phase of calcium carbonate forms~
The formation of scale in industrial aqueous systems represents a major pro~lem since it reduces heat transfer efficiency on heat exchanger surfaces, induces or leads to increased corrosion in the system and reduce~ flow of the water through the system. The addition of inorganic and, more recently all organic polyphosphonates to these aqueous systems is known to inhibit scale formation.
However, due to environmental considerations, there is a _3_ 2 0 74 6 ~i desire to develop non-phosphorus containing scale inhibitors. There are numerous polymeric, non-phosphorus containing scale inhibitors that have recently been developed, however, these compositions have been found to have limited solubility in the hard water systems that are typical of industrial aqueous systems.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a method of inhibiting or preventing the formation of scale in aqueous systems.
It is another object of this invention to provide certain novel scale inhibiting compounds which are soluble in hard water systems; i.e. those systems having relatively high concentrations of calcium.
In accordance with the present invention there has been provided a method of inhibiting scale formation wherein a polyepoxysuccinic acid having the formula:
/ CO2H ~ CO2H
HO ~ ~ OH
wherein n is from 3 to 40 and wherein the polyepoxy-succinic acid is added to the aqueous system in an amount effective to inhibit scale for~ation.
The above scale inhibiting compounds are insensitive to relatively high concentrations of calcium in the treated aqueous system as determined by the CA500 cloud point test.
DETAILED DESCRIPTION
The present invention is directed to a novel method of inhibiting the formation of scale in aqueous systems.
The method involves adding to the systam a polyepoxy-succinic acid in an amount effective to inhibit scale formation. The acid form of the polyepoxysuccinic acids of the present invention can be represented by the following formula:
liO ~-~, 0~~
wherein n is from 3 to about 40, and is preferably from 3 to 10, most preferably from 4 to 7. The polymers may also be used in the form of an alkali metal salt and usually as the sodium salt. Other suitable water soluble salts include potassium, ammonium, zinc, lower amine salts, and the like. The free acids may also be used and all of the acidic hydrogens ne~d not be replaced nor need the cation be the same for those replaced. Thus, the cation may be any one of or a mixture of NH4, H, Na, K, etc. The polymer is converted into ths water soluble salts by conventional methods.
The praparation of the polyepoxysuccinic acids of this invention is disclosed in U.S. Patent Nos. 4,654,159 and 4,846,650 which are incorporated herein in their entirety. In general, the polyepoxysuccinic acids are prepared by treating an epoxysuccinate or an admixture of an epoxysuccinate and a tartrate with an alkaline calcium compound in an aqueous media to form the alkali metal -5- 2~
and/or calcium salks of an ether hydroxy-poly~arboxylate, and optionally separating the salts from the aqu~ous media.
In accordance with this invention, the formation of scale, particularly calcium carbonate scale, may be inhibited by adding the polyepoxysuccinic acid, or its water soluble salts to an aqueous system in an amount effective to either inhibit the formation of scale or to remove scale deposits which may already be present in the system. The precise dosage of the scale inhibiting agents of this invention depends, to some extent, on the nature of the aqueous system in which it is to be incorporated i.e., the amount of hardness causing and scale forming compounds present in the system, and the degree of protection desired, as well a~ the degres of scale which may be deposiked in the system. The compositions of this invention are generally added to the system in sub-stoichiometric amounts to the scale forming salt and accordingly, are known to those skilled in the art as threshold inhibitors. Threshold inhibition describes the phenomenon whereby al sub~stoichiometric amount of a scale inhibitor can st:abilize a solution from precipitation. Threshold inhibition generally takes place under conditions where a small amount i.e. 1 to 100 ppm of a polymeric inhibitor will stabilize the solution which contains many orders of magnitude greater concentration of scale forming salts. ThusJ in general, the amount of polyepoxysuccinic acid added to the system can be from about 0.1 ppm to 1000 ppm and is preferably 0.1 ppm to 100 ppm and is most preferably in the range of from 0.5 to 10 ppm. The exact dosage amount required with respect to a particular aqueous system can be readily determined in conventional manners which are known to those of ordinary skill in the art.
The polymeric scale inhibiting compositions of this invention are particularly suitable for use in aqueous systems having a hi~h degree of hardness and have exhibited a high degre~ of insensitivity to relatively high concentrations of both magnesium and calcium. It is considered an important feature of this invention, that the claimed compositions be calcium insensitive. Calcium sensitivity refers to the tendency of a compound to precipitate with calcium ions in solution. The calcium insensitivity of the claimed compositions pPrmits th~ir use in aqueous systems having water with relatively high hardness. The test for calcium insensitivity of a compound, as used in this application, involves a cloud point test (hereinafter the CA500 cloud point test) where the compound is added to hard water containing 500 ppm calcium ion (as CaC03) which is buffered at pH 8.3 using 0.005 M borate buffer and which has a temperature of 60C. The amount of compound which can be added to the solution until it becomes turbid ~the cloud point) is considered to be an indicator of calcium insensitivity.
The calcium insensitive compounds of this invention have cloud points of at least about 25 ppm as determined by the CA500 cloud point test, and preferably have cloud points of at least about 40 ppm.
The aqueous systems which may be advantageously treated in accordance with the polymers of this invention include, but are not limited to cooling water systems such as e.g. cooling towers, desalinization units, gas scrubbers, as well as to boiler systems and other recirculating water systems where scale deposits are known to form.
The polymers of this invention may be used in combination with other water treatment components customarily employed in the aqueous system including, but ~ ~ 7 ~
not limited to other scale inhibitors, corrosion inhibitors, biocides, dispersing agents, antifoaming agents, oxygen scavengers, s~questering agents, and the like and mixtures thereof.
The polymeric scale inhibitors of this invention may be added to the system by any convenient mode, such as by first forming a concentrated aqueous solution of the polyepoxysuccinic acids or their water soluble salts, preferabJy containing between 1 and 50 total weight percent of the polymer, and then feeding the concentrated aqueous solution to the aqueous system at some convenient point. In many instances the scale inhibitors may be added to the make-up or feedwater lines through which water enters the system. Typi~ally, an injector calibrated to deliver a predetermined amount periodically or continuously to the makeup water is employed.
Without further elaboration, it is believed that one skilled in the art, using the preceding detailed description can utilize the present invention to its fullest extent.
The following examples are provided to illustrate the invention in accordance with t.he principles of this invention, but are not to be const:rued as limiting the invention in any way except as inclicated in the appended claims. All parts and percentages are by weight unless otherwise indicated.
Example 1 Threshold inhibition test measures the ability of a chemical to inhibit calcium carbonate formation.
Laboratory tests for calcium carbonate threshold inhibitors were performed under the following two different water conditions~ water containing 1000 ppm Cat2 and 328 ppm HCO3- (all as CaC03), (2) water containing -8- ~ f~
283 ppm Ca 2, lS4 ppm Mg+2 and 423 ppm HC03- (all as CaCO3).
The test solution was prepared in a 1000 ml beaker and 5 ppm of the additive being tested was added to the above water. The final volume of the solution was made up to 800 ml. The solution was stirred with a magnetic ~tir bar and heated by a stainless steel immersion heater to 120F or 130F depending on the water condition. The pH
of the solution was monitored and adjusted at pH 7~15 with the addition of dilute HCl. On achieving the required temperature, 0.1 N NaOH was added at a rate of 0.32 ml/minute using a syringe pump.
The p~ was monitored and recorded during the titration. A decrease or plateau in pH reading is observed when calcium carbonate starts to precipitate.
This point is termed the critical pH (pHc). An effective threshold inhibitor will raise the critical pH, compared to the blank, and require more base (hydroxide) to reach pHc. Results are summarized in Table 1 and Table 2.
As shown in Table l and Table 2, polyepoxysuccinic acid is an effective calcium carbonate threshold inhibitor. When compared to polymaleic acid, polyacrylic acid, or polymethacrylic acid, the polyepoxysuccinic acid was found to be more effective in inhibiting the formation of calcium carbonate precipitate under two different water conditions.
9 2 ~
Table 1 Threshold Inhibition Meq OH-/Liter Treatment ~-c_ to PHc Blank 7.59 0.48 Tartaric Acid 7.74 0.55 Polymaleic Acid 8.48 1.48 Polyacrylic Acid 8.52 1.31 Polymethacrylic Acid 8.30 0.98 Polyepoxysuccinic Acid 8.53 1.79 1000 ppm Ca+2, 328 ppm HCO3- (as CaCO3, 120F) Table 2 Threshold Inhibition at 283 ppm Ca~2, 184 ppm Mg~2, and 423 HCO3- ~as CaCO3) 130~
Additive Critical pH Meq. OH~/Liter PHc to PHc Blank 3.12 O.91 Polymaleic Acid 9.12 2.79 Polyacrylic Acid 9.33 3.62 Polymethacrylic Acid 8.93 1.78 Polyepoxysuccinic Acid 9.43 3.86 Example 2 Calcium sensitivity test determines the tendency of a chemical to precipitate with calcium ions in solution.
. ~7~
Calcium insensitivity is considered an important feature of this invention because it allows the polymer of this invention to be used effectively in water of relatively high hardness. The test for calcium insensitivity of a compound as used in this application involves a cloud point test where the compound is added to a hard water containing 500 ppm calcium ion (as CaCo3) which is buffered at pH 8.3 using 0.005 M borate buffer and has a temperature of 60C. The amount of compound which can be added until the solution becomes turbid (the cloud point) is considered to be an indicator of calcium sensitivity. The calcium insensitive compounds of this invention have cloud points of at least about 25 ppm as determined by this specific test.
Formation of the co-precipitates of calcium with polyacrylic acid, polymethacrylic acid and polymaleic acid were at cloud points of 4 ppm, 6 ppm, and 12 ppm, respectively. This result indicated that polyacrylic acid, polymethacrylic acid and po].ymaleic acid were very sensitive to calcium hardness and prone to form calcium polymer precipitates at low treatment concentrations. In contrast, the polyepoxysuccinic acid, as illustrated in Table 3, were relatively insensitive to calcium with cloud point at 43 ppm.
Table 3 Calcium Sensitivity Treatment Cloud Point (p~m) Polyacrylic Acid 4 Polymethacrylic Acid 6 Polymaleic Acid 12 Polyepoxysuccinic Acid 43
This invention relates to a method for inhibiting or prevenking the formation of scale on surfaces which are in contact with an aqueous system and more specifically to a method wherein a polyepoxysuccinic acid is added to the system in an amount effective to inhibit the formation of scale.
BA(~KGROUND OF THE I~7ENTION
Most industrial aqueous systems contain alkaline earth metal cation, such as calcium, magnesium and the like as well as numerous anions such as bicarbonate, carbonate, sulfate, and the like. When the concentration of the various combinations of cation and anions exceed the solubility of their reaction products, precipitates tend to form until the product solubility concentrations are no longer exceeded. As these reaction products precipitate on the surfaces of the aqueous systems, the form what is known as scale. The precipitation of calcium carbonate is by far the most common form of scale in industrial aqueous systems. This occurs when the ionic product of calcium and carbonate exceeds the solubility of the calcium carbonate and a solid phase of calcium carbonate forms~
The formation of scale in industrial aqueous systems represents a major pro~lem since it reduces heat transfer efficiency on heat exchanger surfaces, induces or leads to increased corrosion in the system and reduce~ flow of the water through the system. The addition of inorganic and, more recently all organic polyphosphonates to these aqueous systems is known to inhibit scale formation.
However, due to environmental considerations, there is a _3_ 2 0 74 6 ~i desire to develop non-phosphorus containing scale inhibitors. There are numerous polymeric, non-phosphorus containing scale inhibitors that have recently been developed, however, these compositions have been found to have limited solubility in the hard water systems that are typical of industrial aqueous systems.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a method of inhibiting or preventing the formation of scale in aqueous systems.
It is another object of this invention to provide certain novel scale inhibiting compounds which are soluble in hard water systems; i.e. those systems having relatively high concentrations of calcium.
In accordance with the present invention there has been provided a method of inhibiting scale formation wherein a polyepoxysuccinic acid having the formula:
/ CO2H ~ CO2H
HO ~ ~ OH
wherein n is from 3 to 40 and wherein the polyepoxy-succinic acid is added to the aqueous system in an amount effective to inhibit scale for~ation.
The above scale inhibiting compounds are insensitive to relatively high concentrations of calcium in the treated aqueous system as determined by the CA500 cloud point test.
DETAILED DESCRIPTION
The present invention is directed to a novel method of inhibiting the formation of scale in aqueous systems.
The method involves adding to the systam a polyepoxy-succinic acid in an amount effective to inhibit scale formation. The acid form of the polyepoxysuccinic acids of the present invention can be represented by the following formula:
liO ~-~, 0~~
wherein n is from 3 to about 40, and is preferably from 3 to 10, most preferably from 4 to 7. The polymers may also be used in the form of an alkali metal salt and usually as the sodium salt. Other suitable water soluble salts include potassium, ammonium, zinc, lower amine salts, and the like. The free acids may also be used and all of the acidic hydrogens ne~d not be replaced nor need the cation be the same for those replaced. Thus, the cation may be any one of or a mixture of NH4, H, Na, K, etc. The polymer is converted into ths water soluble salts by conventional methods.
The praparation of the polyepoxysuccinic acids of this invention is disclosed in U.S. Patent Nos. 4,654,159 and 4,846,650 which are incorporated herein in their entirety. In general, the polyepoxysuccinic acids are prepared by treating an epoxysuccinate or an admixture of an epoxysuccinate and a tartrate with an alkaline calcium compound in an aqueous media to form the alkali metal -5- 2~
and/or calcium salks of an ether hydroxy-poly~arboxylate, and optionally separating the salts from the aqu~ous media.
In accordance with this invention, the formation of scale, particularly calcium carbonate scale, may be inhibited by adding the polyepoxysuccinic acid, or its water soluble salts to an aqueous system in an amount effective to either inhibit the formation of scale or to remove scale deposits which may already be present in the system. The precise dosage of the scale inhibiting agents of this invention depends, to some extent, on the nature of the aqueous system in which it is to be incorporated i.e., the amount of hardness causing and scale forming compounds present in the system, and the degree of protection desired, as well a~ the degres of scale which may be deposiked in the system. The compositions of this invention are generally added to the system in sub-stoichiometric amounts to the scale forming salt and accordingly, are known to those skilled in the art as threshold inhibitors. Threshold inhibition describes the phenomenon whereby al sub~stoichiometric amount of a scale inhibitor can st:abilize a solution from precipitation. Threshold inhibition generally takes place under conditions where a small amount i.e. 1 to 100 ppm of a polymeric inhibitor will stabilize the solution which contains many orders of magnitude greater concentration of scale forming salts. ThusJ in general, the amount of polyepoxysuccinic acid added to the system can be from about 0.1 ppm to 1000 ppm and is preferably 0.1 ppm to 100 ppm and is most preferably in the range of from 0.5 to 10 ppm. The exact dosage amount required with respect to a particular aqueous system can be readily determined in conventional manners which are known to those of ordinary skill in the art.
The polymeric scale inhibiting compositions of this invention are particularly suitable for use in aqueous systems having a hi~h degree of hardness and have exhibited a high degre~ of insensitivity to relatively high concentrations of both magnesium and calcium. It is considered an important feature of this invention, that the claimed compositions be calcium insensitive. Calcium sensitivity refers to the tendency of a compound to precipitate with calcium ions in solution. The calcium insensitivity of the claimed compositions pPrmits th~ir use in aqueous systems having water with relatively high hardness. The test for calcium insensitivity of a compound, as used in this application, involves a cloud point test (hereinafter the CA500 cloud point test) where the compound is added to hard water containing 500 ppm calcium ion (as CaC03) which is buffered at pH 8.3 using 0.005 M borate buffer and which has a temperature of 60C. The amount of compound which can be added to the solution until it becomes turbid ~the cloud point) is considered to be an indicator of calcium insensitivity.
The calcium insensitive compounds of this invention have cloud points of at least about 25 ppm as determined by the CA500 cloud point test, and preferably have cloud points of at least about 40 ppm.
The aqueous systems which may be advantageously treated in accordance with the polymers of this invention include, but are not limited to cooling water systems such as e.g. cooling towers, desalinization units, gas scrubbers, as well as to boiler systems and other recirculating water systems where scale deposits are known to form.
The polymers of this invention may be used in combination with other water treatment components customarily employed in the aqueous system including, but ~ ~ 7 ~
not limited to other scale inhibitors, corrosion inhibitors, biocides, dispersing agents, antifoaming agents, oxygen scavengers, s~questering agents, and the like and mixtures thereof.
The polymeric scale inhibitors of this invention may be added to the system by any convenient mode, such as by first forming a concentrated aqueous solution of the polyepoxysuccinic acids or their water soluble salts, preferabJy containing between 1 and 50 total weight percent of the polymer, and then feeding the concentrated aqueous solution to the aqueous system at some convenient point. In many instances the scale inhibitors may be added to the make-up or feedwater lines through which water enters the system. Typi~ally, an injector calibrated to deliver a predetermined amount periodically or continuously to the makeup water is employed.
Without further elaboration, it is believed that one skilled in the art, using the preceding detailed description can utilize the present invention to its fullest extent.
The following examples are provided to illustrate the invention in accordance with t.he principles of this invention, but are not to be const:rued as limiting the invention in any way except as inclicated in the appended claims. All parts and percentages are by weight unless otherwise indicated.
Example 1 Threshold inhibition test measures the ability of a chemical to inhibit calcium carbonate formation.
Laboratory tests for calcium carbonate threshold inhibitors were performed under the following two different water conditions~ water containing 1000 ppm Cat2 and 328 ppm HCO3- (all as CaC03), (2) water containing -8- ~ f~
283 ppm Ca 2, lS4 ppm Mg+2 and 423 ppm HC03- (all as CaCO3).
The test solution was prepared in a 1000 ml beaker and 5 ppm of the additive being tested was added to the above water. The final volume of the solution was made up to 800 ml. The solution was stirred with a magnetic ~tir bar and heated by a stainless steel immersion heater to 120F or 130F depending on the water condition. The pH
of the solution was monitored and adjusted at pH 7~15 with the addition of dilute HCl. On achieving the required temperature, 0.1 N NaOH was added at a rate of 0.32 ml/minute using a syringe pump.
The p~ was monitored and recorded during the titration. A decrease or plateau in pH reading is observed when calcium carbonate starts to precipitate.
This point is termed the critical pH (pHc). An effective threshold inhibitor will raise the critical pH, compared to the blank, and require more base (hydroxide) to reach pHc. Results are summarized in Table 1 and Table 2.
As shown in Table l and Table 2, polyepoxysuccinic acid is an effective calcium carbonate threshold inhibitor. When compared to polymaleic acid, polyacrylic acid, or polymethacrylic acid, the polyepoxysuccinic acid was found to be more effective in inhibiting the formation of calcium carbonate precipitate under two different water conditions.
9 2 ~
Table 1 Threshold Inhibition Meq OH-/Liter Treatment ~-c_ to PHc Blank 7.59 0.48 Tartaric Acid 7.74 0.55 Polymaleic Acid 8.48 1.48 Polyacrylic Acid 8.52 1.31 Polymethacrylic Acid 8.30 0.98 Polyepoxysuccinic Acid 8.53 1.79 1000 ppm Ca+2, 328 ppm HCO3- (as CaCO3, 120F) Table 2 Threshold Inhibition at 283 ppm Ca~2, 184 ppm Mg~2, and 423 HCO3- ~as CaCO3) 130~
Additive Critical pH Meq. OH~/Liter PHc to PHc Blank 3.12 O.91 Polymaleic Acid 9.12 2.79 Polyacrylic Acid 9.33 3.62 Polymethacrylic Acid 8.93 1.78 Polyepoxysuccinic Acid 9.43 3.86 Example 2 Calcium sensitivity test determines the tendency of a chemical to precipitate with calcium ions in solution.
. ~7~
Calcium insensitivity is considered an important feature of this invention because it allows the polymer of this invention to be used effectively in water of relatively high hardness. The test for calcium insensitivity of a compound as used in this application involves a cloud point test where the compound is added to a hard water containing 500 ppm calcium ion (as CaCo3) which is buffered at pH 8.3 using 0.005 M borate buffer and has a temperature of 60C. The amount of compound which can be added until the solution becomes turbid (the cloud point) is considered to be an indicator of calcium sensitivity. The calcium insensitive compounds of this invention have cloud points of at least about 25 ppm as determined by this specific test.
Formation of the co-precipitates of calcium with polyacrylic acid, polymethacrylic acid and polymaleic acid were at cloud points of 4 ppm, 6 ppm, and 12 ppm, respectively. This result indicated that polyacrylic acid, polymethacrylic acid and po].ymaleic acid were very sensitive to calcium hardness and prone to form calcium polymer precipitates at low treatment concentrations. In contrast, the polyepoxysuccinic acid, as illustrated in Table 3, were relatively insensitive to calcium with cloud point at 43 ppm.
Table 3 Calcium Sensitivity Treatment Cloud Point (p~m) Polyacrylic Acid 4 Polymethacrylic Acid 6 Polymaleic Acid 12 Polyepoxysuccinic Acid 43
Claims (10)
1. A method for inhibiting or preventing the formation of scale on surfaces in contact with an aqueous system comprising adding to the system a polyepoxy-succinic acid having the formula wherein n is from 3 to 40 and wherein the polyepoxy-succinic acid is added in an amount effective to inhibit scale formation.
2. A method according to claim 1 wherein the effective amount is in the range of from 0.1 to 1000 ppm.
3. A method according to claim 1 wherein the effective amount is in the range of from 0.1 to 100 ppm.
4. A method according to claim 1 wherein the effective amount is in the range of from 0.5 to 10 ppm.
5. A method according to claim 1 wherein the effective amount is in the range of from 3 to 10 ppm.
6. A method according to claim 1 wherein the effective amount is in the range of from 4 to 7 ppm.
7. A method according to Claim 1 wherein the scale in calcium carbonate.
8. A method according to Claim 1 wherein the polyepoxysuccinic acid is added in the form of a water-soluble salt.
9. A method according to Claim 1 wherein the polyepoxysuccinic acid is added in the form of an alkali metal salt.
10. A method according to Claim 1 wherein the polyepoxysuccinic acid is added in the form of the sodium salt.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US78284991A | 1991-10-24 | 1991-10-24 | |
| US782,849 | 1991-10-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2074609A1 true CA2074609A1 (en) | 1993-04-25 |
Family
ID=25127371
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2074609 Abandoned CA2074609A1 (en) | 1991-10-24 | 1992-07-24 | Inhibition of scale formation by polyepoxysuccinic acid |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU1968792A (en) |
| CA (1) | CA2074609A1 (en) |
| ZA (1) | ZA925050B (en) |
-
1992
- 1992-07-07 ZA ZA925050A patent/ZA925050B/en unknown
- 1992-07-15 AU AU19687/92A patent/AU1968792A/en not_active Abandoned
- 1992-07-24 CA CA 2074609 patent/CA2074609A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| AU1968792A (en) | 1993-04-29 |
| ZA925050B (en) | 1993-04-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4457847A (en) | Carboxylate polymers for internal scale control agents in boiler systems | |
| CA1205715A (en) | Systems inhibited against corrosion and/or scale deposition | |
| US4512552A (en) | Corrosion inhibitor | |
| EP0122013B1 (en) | Polymeric additives for water | |
| US4952327A (en) | Scale control with terpolymers containing styrene sulfonic acid | |
| US4617129A (en) | Scale inhibition | |
| US5308498A (en) | Hydroxamic acid containing polymers used as corrosion inhibitors | |
| US5183573A (en) | Multipurpose scale preventer/remover | |
| KR100378312B1 (en) | Chemical for water treatment | |
| KR100268958B1 (en) | Phosphinic acid-containing polymers and their use in preventing scale and corrosion | |
| US5139702A (en) | Naphthylamine polycarboxylic acids | |
| WO1983002607A1 (en) | Process for inhibiting scale | |
| US4707271A (en) | Stabilization of iron in aqueous systems | |
| US4545920A (en) | Boiler water treating compositions | |
| US4889637A (en) | Scale control with terpolymers containing vinyl alcohol | |
| US5344590A (en) | Method for inhibiting corrosion of metals using polytartaric acids | |
| US5298221A (en) | Inhibition of scale formation and corrosion by sulfonated organophosphonates | |
| CA2073660C (en) | Substituted carboxymethoxysuccinic acid corrosion inhibitors | |
| CA2074609A1 (en) | Inhibition of scale formation by polyepoxysuccinic acid | |
| KR900003981B1 (en) | Method for corrosion inhibition of metals | |
| US5015390A (en) | Method for controlling scale deposition in aqueous systems using quaternary ammonium/maleic anhydride-type polymers | |
| US4925568A (en) | Polyacrylate blends as boiler scale inhibitors | |
| EP0257876B1 (en) | Polyacrylate blends as boiler scale inhibitors | |
| EP0543473B1 (en) | Copolymers and their use in dispersing iron | |
| EP0350985B1 (en) | Method for controlling scale deposition in aqueous systems using quaternary ammonium/maleic anhydride-type polymers |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |