CA2083453A1 - Methods of controlling scale formation in aqueous systems - Google Patents
Methods of controlling scale formation in aqueous systemsInfo
- Publication number
- CA2083453A1 CA2083453A1 CA002083453A CA2083453A CA2083453A1 CA 2083453 A1 CA2083453 A1 CA 2083453A1 CA 002083453 A CA002083453 A CA 002083453A CA 2083453 A CA2083453 A CA 2083453A CA 2083453 A1 CA2083453 A1 CA 2083453A1
- Authority
- CA
- Canada
- Prior art keywords
- ppm
- pesa
- scale
- acrylic acid
- polyepoxysuccinic
- 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
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
- C02F5/08—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents
- C02F5/10—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents using organic substances
- C02F5/105—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents using organic substances combined with inorganic substances
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
- C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
Abstract
ABSTRACT OF THE DISCLOSURE
The treatment of an aqueous system to inhibit scale formation with a polyepoxysuccinic acid scale inhibitor, an acrylic acid copolymer and a lanthanide ion blending agent.
The treatment of an aqueous system to inhibit scale formation with a polyepoxysuccinic acid scale inhibitor, an acrylic acid copolymer and a lanthanide ion blending agent.
Description
5~83 ~r~3 METHODS OF CONTROLLING SCALE FORMATION
IN AQUEOUS SYSTEMS
FIELD OF THE INVENTION
The present invention relates to the treatment of water 5 to inhibit the formation of scale. More particularly, the present invention relates to a treatment for an aqueous system which comprises a polyepoxysuccinic acid scale inhibitor, an acryiic acid copolymer and a lanthanide ion blending agent.
BACK~ROUND OF THE INVENTION
Although the present invention has general applicability to any given system where the formation and deposition of scale and in particular calcium scale is a potential problem, the in-vention will be discussed in detail as it concerns cooling water systems. The present invention relates to methods for inhibiting scale deposits and fouling in aqueous systems.
In industrial cooling systems, water such as from rivers, lakes, ponds, etc., is employed as the cooling media $or heat exchangers. Such natural waters contain large amounts of 2 ~ 3 suspended material such as s~lt, clay, and organic wastes. The cooliny water from a heat exchanger is typically passed through a cooling tower, spray pond or evaporative system prior to discharge or reuse. In such systems, cooling is achieved by evaporating a portion of the water passing through the system.
Because of the evaporation which takes place during cooling, suspended materials in the water become concentrated. Fouling materials from the feedwater or as a result of evaporatiYe concentration can settle in locations of low flow rates and cause corrosion and inefficient heat transfer. Agglomerating agents such as polyacrylamides and polyacrylates have been used to agglomerate fine particles of mud and sil~ into a loose floc for removal. However, these flocs tend to settle in cooling tower basins and frequent cleaning is necessary to remove the settled flocs from the tower basins. Dispersants are typically employed to inhibit fouling caused by the adherence of such particles on heat transfer surfaces. Often such dispersants are copolymers of acrylic acid. For example polyacrylic acid, acry-lic acid/1-allyloxy-2-propanol copolymer, acrylic acid/allyl hydroxypropylsulfonate ether sodium salt copolymer and acrylic acid/polyethylene glycol allyl ether copolymer.
The water employed in industrial cooling water systems also often contains dissolved salts of calcium, magnesium ekc.9 which can lead to scale and sludge deposits. One of the most common scale deposits in cooling systems is calcium carbonate.
It normally results from the breakdown of calcium bicarbonate~
2~g3~3 a naturally occurring soluble salt. Calcium carbonate has a relatively low solubility and its solubility decreases with increasing temperature and pH. Thus, the rate of calcium carbo-nate deposition increases with increasiny pH and temperature.
Deposit control agents such as phosphates, phosphonates and polyacrylates are often used to inhibit calcium carbonate scale forma~ion in industrial cooling water systems. These poly-acrylates alone are not effective at high calcium concentrations because undesirable polyacrylate-calcium adducts are formed re-ducing efficacy. Although phosphonates are very efficient at controlling calcium carbonate scale formation, they can produce insoluble phosphonate-calcium complexes or calcium phosphate scale upon degradation. Further, current limits on phosphate discharge limit the acceptability of the use of phosphonates for water treatment.
Preventing the corrosion and scaling of industrial heat transfer equipment is essential to the efficient and economical operat;on of a cooling water system. Excessive corros;on of metallic surfaces can cause the premature failure of process equipment, necessitating down time for the replacement or repair of the equipment Additionally, the buildup of corrosion prcducts on heat transfer surfaces impedes water flow and reduces heat transfer efficiency thereby limiting production or requiring downtime for c`leaning. Reduction in efficiency will also result from scaling deposits which retard heat transfer and hinder water flow.
2~34~3 _D,--Scale can also cause rapid localized corrosion and subsequent penetration of metallic surfaces through the formation of dif-ferential oxygen concentration cells. The localized corrosion resulting from differential oxygen cells originating from deposits is commonly referred to as "under deposit corrosion".
The treatment of industrial waters to inhibit scale fvrmation with polyepoxysuccinic acid ~hereinafter PESA) is disclosed in U.S. Patent 5,062,962 incorporated herein by reference. The general formula for PESA is:
R R
H0 -~- C - C - 0 --3~ H
O = l l = O
M M
where n ranges from about 2 to '50, preferably, 2 to 25, M is hy-drogen or a water soluble cation such as Na+, NH4+ or K+
and'R is hydrogen, C I - 4 alkyl-or C 1 - 4 substituted alkyl (preferably R as hydrogen). PESA is known to be an effective inhibitor for scale control. Howeyer, it was found that when PESA
was employed in combination with acrylic acid copolymers commonly employed as dispersants, corrosion inhibitors or deposit control agents there was a decrease in efficacy of the scale inhibiting properties of PESA.
'~6~3~3 SUMMARY OF THE INVENTION
The present invention provides an effective m~thod for inhibiting scale formation in aqueous systems by employing PESA
in combination with an acrylic acid copolymer treatment. The method of the present invention enhances the efficacy of PESA and also avnids the interferencQ between acrylic ac;d copolymer treatments and PESA. The method of the present inYention was also found to inhibit corrosion on low carbon steei surfaces.
The present invention provides a method for inhibiting scale formation in aqueous systems which is effective at conditions of high pH, high calcium concentration and high M alkalinity where convent;onal calcium control treatments lose efficacy. The present invention controls calcium scale format;on and fouling of heat transfer surfaces without the formation of undesirable 1~ inhibitor - calcium complexes. Also, the method of the present invention does not employ phosphorous thereby,eliminating the undesirable discharge of phosphorous containing compounds. The method of the present invention is effective at treating waters having low levels of calcium as well as those having high calcium levels.
The present invention is effective at inhibiting the deposition of scale forming materials such as calcium oxylate, calcium sulfate, barium sulfate as well as the more common calcium carbonate. The present invention is also effective at high pH calcium carbo~ate inhibition as required in paper mills.
2~83~3 The method of the present invention comprises treating industrial water with a combination of: a polyepoxysuccinic acid of the general formula R R
H0 ~ ~ ]n H
O = C C = O
O O
'I I
M M
where n ranges from about 2 to 50, preferably 2 to 25~ and M is hydrogen or a water soluble cation such as Na+, NH4+ or K+
and R is hydrogen, C 1 - 4 alkyl or C 1 - 4 substituted alkyl (preferably R as hydrogen); an acryl;c acid copolymer which can function as a dispersing agent, a corrosion control agent or a deposit control agent; and lanthanide ion(s). Exemplary acrylic acid copolymers include polyacrylic acid and (meth)acrylic acid/allyl ether copolymers.
In the present ;nvention, the polyepoxysuccinic acids are added to aqueous systems at substoichiometr;c levels to inh;b;t scale ~ormation, the acrylic acid copolymer is added to avoid fouling caused by the adherence of particles to heat transfer surfaces and the lanthanide ions are added in amounts sufficient to inhibit interference between the acrylic acid copolymer and the polyepoxysuccinic acid.
2~3~
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention pertains to a novel method ~f inhibiting the formation of scale such as calcium scale from aqueous systems and inhibiting the fouling caused by the adherence of particles to heat transfer surfaces in an aqueous system.
Specif;cally, the method of the present invention comprises adding to an aqueous system a treatment sslution comprising a combination of: a polyepoxysuccinic acid of the general formula R R
HO -~ C - C - ]n H
O = C C = O
O l M M
where n ranges from about ~ to 50, preferably 2 to 25, and M is hydrogen or a water soluble cation such as Na~, NH4+ or K+
and R is hydrogen, C 1 - 4 alkyl or C 1 - 4 subst;tuted alkyl (preferably R as hydrogen); an acrylic acid copolymer such as a (meth)acrylic acid/allyl ether copolymer; and a lanthanide ion.
Polyepoxysuccinic acids are known to provide. calcium scale inhibitinn comparable to prior art phosphates, phosphonates and polyacrylates without the recognized limitations of these prior art treatments. Polyepoxysucc;nic acids are effective in all ' .
~3~3 water systems, and particularly effective in aqueous systems having relatively high Langelier Saturation Index (LSI) numbers, that is in the range of 2.5 to 3Ø U.S. Patent No. S,062,962 (incorporated herein by reference) outlines a method of preparing the polyepoxysuccinic acid material of the present invention. The treatment levels of polyepoxysuccinic acid added to an aqueous system can range from about 25 parts per billion up to about 500 parts per million. The preferred treatment levels range from about 5 part per million up to about 100 parts per million. The concentration of polyepoxysuccinic acid necessary to provide effective scale control will vary from system to system. The treatment level will vary in part, with changes in temperature, pH, and LSI. However, in all cases, the concentration of polyepoxy-succinic acid added to an aqueous system in accordance ~ith the present invention is at substoichiometric concentrations. That is, the concentration of polyepoxysuccinic acid added is much lower than the concentration of the scale forming material in the system to be treated.
The acrylic acid copolymers of the present invention are those known ts be effective in aqueous systems for corrosion inhibition, scale control and as dispersants. Exemplary acrylic acid copolymers include polyacrylic acid and (meth3acrylic acid/-allyl ether copolymers as described in commonly assigned U.S.
Patent No. 4,872,995 incorporated herein by reference. (Meth3-acrylic acid/allyl copolymers described therein include acrylicacid/l-allyloxy-2-propanol (AA/AOP), acrylic acid/allylhydroxy-propylsulfonate ether sodium salt (AA/AHPSE) and acrylic acid/poly-ethyleneglycol allyl ether ~AA/PEGAE).
2 ~ 3 Such acrylic acid copolymers are known to have a variety of uses in the treatment of aqueous systems. However, when employed in combination with the known scale control agent PESA
there is a marked decrease in the effectiveness of the PESA scale control agent. It was found that when a lanthanide ion was added to an aqueous system in combination with PESA and an acrylic acid copolymer the efficacy of the PESA was actually increased, the interference between the PESA and the acrylic acid copolymer was inhibited and also corrosion on low carbon steel surfaces decreased. The lanthanide ions of the present invention include any member of lanthanide series (the rare earth elements) preferably lanthanum, praseodymium and neodymium. The lanthanide ion may be added to an aqueous system in the form of their salts preferably their chloride salts. The lanthanide ions can be added in concentration ranges of from about 2 parts per billion up to about 25 parts per million, preferably from about 0.1 to 3.0 p~rts per million.
The present invention will now be described with reference to a number of specific examples which are to be regarded solely as illustr~tive and not as restricting the scope of the present invention.
EXAMPLES
Static testing was undertaken to evaluate the calcium carbonate inhibition activity of polyepoxysuccinic acid alone as well as in combination with lanthanum ions, AA/AHPSE and AA/AHPSE
2~3~
plus lanthanum ions. In the testing two different molecular weights of AA/AHPSE were tested: AA/AHPSEI has a lower molecular weight than AA/AHPSEII. The test conditions were:
pH = 9.0, Temperature = 70C, 1102 ppm Ca2+ as CaC03, 1170 ppm co2- as CaC03, LSI = 3.2, duration 18 hours.
Table 1 summarizes the test results.
Treatment % Inhibition 2 ppm PESA 25.1 105 ppm PESA 58. a 10 ppm PESA B7.2 1 ppm La 22.1 2 ppm PESA ~ 1 ppm La 40.1 5 ppm PESA ~ 1 ppm La 62.0 155 ppm PESA + 5 ppm AA/AHPSE I 48.1 10 ppm PESA + 5 ppm AA/AHPSE I 64.3 S ppm PESA ~ 5 ppm AA/AHPSE I + 1 ppm La 65.2 10 ppm PESA + 5 ppm AA/AHPSE I + 1 ppm La 91.8 All M/AHPSE concentrations are glven as active polymer concentration.
As shown in Table 1, PESA alone was an effective calcium carbonate control agent. Lanthanum by itself does not appear to have a significant effect on the act;vity of the PESA. When PESA
and M/AHPSE are combined there is a decrease in effectiveness as evidenced by the decrease in % inhibition. When the lanthanum is added to a combination of PESA and AA/AHPSE there is a significant improvement in the % inhibition.
~3~3 At the conclusion of static testing, dynamic r~circulator testing was undertaken. The recirculator system is designed to provide a realistic measure of the ability of a treatment in accordanoe with the present invention to inhibit corrosion and fouling under heat transfer sonditions. In this system, treated water is circulated by a ~entrifugal pump through a currosion coupon by-pass rack, into which corrosion coupons ~Adm;ralty, brass or low carbon steel) are inserted, and past a mild steel or 316 stainless steel heat exchanger $ube contained in a Plexiglas (trademark of Rohm and Haas Co.) block. The heat exchanger tube is fitted with an electrical heater so that the heat load on the tube can be varied and controlled in the 0 to 16,000 BTU/ft2/
hour range. The water velocity passed the corrosion coupons and heat exchanger tubes is equivalent at any given flow rate and can be controlled anywhere from 0 to 4.5 ft/sec.
The pH and temperature of the recirculating water are automatically controlled. The treated water is prepared by chemical addition to deionized water. Provisions for continuous makeup and blowdown are made by pumpins~ fresh treated water from supply tanks to the sump of the unit, with overflow from the sump serving as blowdown. The total system volume is about 12 liters. Tables 2 and 3 summarize the results of tests run at different conditions of M alkalinity.
~3~3 Dynamic Testinq Conditions:
M - Alk = 250 600 ppm Ca2~ as CaO03 pH = 8.5 LSI = 2.2 2 200 ppm Mg2+ as CaC03 Heat Flux = 15600 Btu/hr.ft 406 ppm NaHC03 Sol. velocity = 4 gpm 50 ppm SiO2 Temperature = 120F
IN AQUEOUS SYSTEMS
FIELD OF THE INVENTION
The present invention relates to the treatment of water 5 to inhibit the formation of scale. More particularly, the present invention relates to a treatment for an aqueous system which comprises a polyepoxysuccinic acid scale inhibitor, an acryiic acid copolymer and a lanthanide ion blending agent.
BACK~ROUND OF THE INVENTION
Although the present invention has general applicability to any given system where the formation and deposition of scale and in particular calcium scale is a potential problem, the in-vention will be discussed in detail as it concerns cooling water systems. The present invention relates to methods for inhibiting scale deposits and fouling in aqueous systems.
In industrial cooling systems, water such as from rivers, lakes, ponds, etc., is employed as the cooling media $or heat exchangers. Such natural waters contain large amounts of 2 ~ 3 suspended material such as s~lt, clay, and organic wastes. The cooliny water from a heat exchanger is typically passed through a cooling tower, spray pond or evaporative system prior to discharge or reuse. In such systems, cooling is achieved by evaporating a portion of the water passing through the system.
Because of the evaporation which takes place during cooling, suspended materials in the water become concentrated. Fouling materials from the feedwater or as a result of evaporatiYe concentration can settle in locations of low flow rates and cause corrosion and inefficient heat transfer. Agglomerating agents such as polyacrylamides and polyacrylates have been used to agglomerate fine particles of mud and sil~ into a loose floc for removal. However, these flocs tend to settle in cooling tower basins and frequent cleaning is necessary to remove the settled flocs from the tower basins. Dispersants are typically employed to inhibit fouling caused by the adherence of such particles on heat transfer surfaces. Often such dispersants are copolymers of acrylic acid. For example polyacrylic acid, acry-lic acid/1-allyloxy-2-propanol copolymer, acrylic acid/allyl hydroxypropylsulfonate ether sodium salt copolymer and acrylic acid/polyethylene glycol allyl ether copolymer.
The water employed in industrial cooling water systems also often contains dissolved salts of calcium, magnesium ekc.9 which can lead to scale and sludge deposits. One of the most common scale deposits in cooling systems is calcium carbonate.
It normally results from the breakdown of calcium bicarbonate~
2~g3~3 a naturally occurring soluble salt. Calcium carbonate has a relatively low solubility and its solubility decreases with increasing temperature and pH. Thus, the rate of calcium carbo-nate deposition increases with increasiny pH and temperature.
Deposit control agents such as phosphates, phosphonates and polyacrylates are often used to inhibit calcium carbonate scale forma~ion in industrial cooling water systems. These poly-acrylates alone are not effective at high calcium concentrations because undesirable polyacrylate-calcium adducts are formed re-ducing efficacy. Although phosphonates are very efficient at controlling calcium carbonate scale formation, they can produce insoluble phosphonate-calcium complexes or calcium phosphate scale upon degradation. Further, current limits on phosphate discharge limit the acceptability of the use of phosphonates for water treatment.
Preventing the corrosion and scaling of industrial heat transfer equipment is essential to the efficient and economical operat;on of a cooling water system. Excessive corros;on of metallic surfaces can cause the premature failure of process equipment, necessitating down time for the replacement or repair of the equipment Additionally, the buildup of corrosion prcducts on heat transfer surfaces impedes water flow and reduces heat transfer efficiency thereby limiting production or requiring downtime for c`leaning. Reduction in efficiency will also result from scaling deposits which retard heat transfer and hinder water flow.
2~34~3 _D,--Scale can also cause rapid localized corrosion and subsequent penetration of metallic surfaces through the formation of dif-ferential oxygen concentration cells. The localized corrosion resulting from differential oxygen cells originating from deposits is commonly referred to as "under deposit corrosion".
The treatment of industrial waters to inhibit scale fvrmation with polyepoxysuccinic acid ~hereinafter PESA) is disclosed in U.S. Patent 5,062,962 incorporated herein by reference. The general formula for PESA is:
R R
H0 -~- C - C - 0 --3~ H
O = l l = O
M M
where n ranges from about 2 to '50, preferably, 2 to 25, M is hy-drogen or a water soluble cation such as Na+, NH4+ or K+
and'R is hydrogen, C I - 4 alkyl-or C 1 - 4 substituted alkyl (preferably R as hydrogen). PESA is known to be an effective inhibitor for scale control. Howeyer, it was found that when PESA
was employed in combination with acrylic acid copolymers commonly employed as dispersants, corrosion inhibitors or deposit control agents there was a decrease in efficacy of the scale inhibiting properties of PESA.
'~6~3~3 SUMMARY OF THE INVENTION
The present invention provides an effective m~thod for inhibiting scale formation in aqueous systems by employing PESA
in combination with an acrylic acid copolymer treatment. The method of the present invention enhances the efficacy of PESA and also avnids the interferencQ between acrylic ac;d copolymer treatments and PESA. The method of the present inYention was also found to inhibit corrosion on low carbon steei surfaces.
The present invention provides a method for inhibiting scale formation in aqueous systems which is effective at conditions of high pH, high calcium concentration and high M alkalinity where convent;onal calcium control treatments lose efficacy. The present invention controls calcium scale format;on and fouling of heat transfer surfaces without the formation of undesirable 1~ inhibitor - calcium complexes. Also, the method of the present invention does not employ phosphorous thereby,eliminating the undesirable discharge of phosphorous containing compounds. The method of the present invention is effective at treating waters having low levels of calcium as well as those having high calcium levels.
The present invention is effective at inhibiting the deposition of scale forming materials such as calcium oxylate, calcium sulfate, barium sulfate as well as the more common calcium carbonate. The present invention is also effective at high pH calcium carbo~ate inhibition as required in paper mills.
2~83~3 The method of the present invention comprises treating industrial water with a combination of: a polyepoxysuccinic acid of the general formula R R
H0 ~ ~ ]n H
O = C C = O
O O
'I I
M M
where n ranges from about 2 to 50, preferably 2 to 25~ and M is hydrogen or a water soluble cation such as Na+, NH4+ or K+
and R is hydrogen, C 1 - 4 alkyl or C 1 - 4 substituted alkyl (preferably R as hydrogen); an acryl;c acid copolymer which can function as a dispersing agent, a corrosion control agent or a deposit control agent; and lanthanide ion(s). Exemplary acrylic acid copolymers include polyacrylic acid and (meth)acrylic acid/allyl ether copolymers.
In the present ;nvention, the polyepoxysuccinic acids are added to aqueous systems at substoichiometr;c levels to inh;b;t scale ~ormation, the acrylic acid copolymer is added to avoid fouling caused by the adherence of particles to heat transfer surfaces and the lanthanide ions are added in amounts sufficient to inhibit interference between the acrylic acid copolymer and the polyepoxysuccinic acid.
2~3~
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention pertains to a novel method ~f inhibiting the formation of scale such as calcium scale from aqueous systems and inhibiting the fouling caused by the adherence of particles to heat transfer surfaces in an aqueous system.
Specif;cally, the method of the present invention comprises adding to an aqueous system a treatment sslution comprising a combination of: a polyepoxysuccinic acid of the general formula R R
HO -~ C - C - ]n H
O = C C = O
O l M M
where n ranges from about ~ to 50, preferably 2 to 25, and M is hydrogen or a water soluble cation such as Na~, NH4+ or K+
and R is hydrogen, C 1 - 4 alkyl or C 1 - 4 subst;tuted alkyl (preferably R as hydrogen); an acrylic acid copolymer such as a (meth)acrylic acid/allyl ether copolymer; and a lanthanide ion.
Polyepoxysuccinic acids are known to provide. calcium scale inhibitinn comparable to prior art phosphates, phosphonates and polyacrylates without the recognized limitations of these prior art treatments. Polyepoxysucc;nic acids are effective in all ' .
~3~3 water systems, and particularly effective in aqueous systems having relatively high Langelier Saturation Index (LSI) numbers, that is in the range of 2.5 to 3Ø U.S. Patent No. S,062,962 (incorporated herein by reference) outlines a method of preparing the polyepoxysuccinic acid material of the present invention. The treatment levels of polyepoxysuccinic acid added to an aqueous system can range from about 25 parts per billion up to about 500 parts per million. The preferred treatment levels range from about 5 part per million up to about 100 parts per million. The concentration of polyepoxysuccinic acid necessary to provide effective scale control will vary from system to system. The treatment level will vary in part, with changes in temperature, pH, and LSI. However, in all cases, the concentration of polyepoxy-succinic acid added to an aqueous system in accordance ~ith the present invention is at substoichiometric concentrations. That is, the concentration of polyepoxysuccinic acid added is much lower than the concentration of the scale forming material in the system to be treated.
The acrylic acid copolymers of the present invention are those known ts be effective in aqueous systems for corrosion inhibition, scale control and as dispersants. Exemplary acrylic acid copolymers include polyacrylic acid and (meth3acrylic acid/-allyl ether copolymers as described in commonly assigned U.S.
Patent No. 4,872,995 incorporated herein by reference. (Meth3-acrylic acid/allyl copolymers described therein include acrylicacid/l-allyloxy-2-propanol (AA/AOP), acrylic acid/allylhydroxy-propylsulfonate ether sodium salt (AA/AHPSE) and acrylic acid/poly-ethyleneglycol allyl ether ~AA/PEGAE).
2 ~ 3 Such acrylic acid copolymers are known to have a variety of uses in the treatment of aqueous systems. However, when employed in combination with the known scale control agent PESA
there is a marked decrease in the effectiveness of the PESA scale control agent. It was found that when a lanthanide ion was added to an aqueous system in combination with PESA and an acrylic acid copolymer the efficacy of the PESA was actually increased, the interference between the PESA and the acrylic acid copolymer was inhibited and also corrosion on low carbon steel surfaces decreased. The lanthanide ions of the present invention include any member of lanthanide series (the rare earth elements) preferably lanthanum, praseodymium and neodymium. The lanthanide ion may be added to an aqueous system in the form of their salts preferably their chloride salts. The lanthanide ions can be added in concentration ranges of from about 2 parts per billion up to about 25 parts per million, preferably from about 0.1 to 3.0 p~rts per million.
The present invention will now be described with reference to a number of specific examples which are to be regarded solely as illustr~tive and not as restricting the scope of the present invention.
EXAMPLES
Static testing was undertaken to evaluate the calcium carbonate inhibition activity of polyepoxysuccinic acid alone as well as in combination with lanthanum ions, AA/AHPSE and AA/AHPSE
2~3~
plus lanthanum ions. In the testing two different molecular weights of AA/AHPSE were tested: AA/AHPSEI has a lower molecular weight than AA/AHPSEII. The test conditions were:
pH = 9.0, Temperature = 70C, 1102 ppm Ca2+ as CaC03, 1170 ppm co2- as CaC03, LSI = 3.2, duration 18 hours.
Table 1 summarizes the test results.
Treatment % Inhibition 2 ppm PESA 25.1 105 ppm PESA 58. a 10 ppm PESA B7.2 1 ppm La 22.1 2 ppm PESA ~ 1 ppm La 40.1 5 ppm PESA ~ 1 ppm La 62.0 155 ppm PESA + 5 ppm AA/AHPSE I 48.1 10 ppm PESA + 5 ppm AA/AHPSE I 64.3 S ppm PESA ~ 5 ppm AA/AHPSE I + 1 ppm La 65.2 10 ppm PESA + 5 ppm AA/AHPSE I + 1 ppm La 91.8 All M/AHPSE concentrations are glven as active polymer concentration.
As shown in Table 1, PESA alone was an effective calcium carbonate control agent. Lanthanum by itself does not appear to have a significant effect on the act;vity of the PESA. When PESA
and M/AHPSE are combined there is a decrease in effectiveness as evidenced by the decrease in % inhibition. When the lanthanum is added to a combination of PESA and AA/AHPSE there is a significant improvement in the % inhibition.
~3~3 At the conclusion of static testing, dynamic r~circulator testing was undertaken. The recirculator system is designed to provide a realistic measure of the ability of a treatment in accordanoe with the present invention to inhibit corrosion and fouling under heat transfer sonditions. In this system, treated water is circulated by a ~entrifugal pump through a currosion coupon by-pass rack, into which corrosion coupons ~Adm;ralty, brass or low carbon steel) are inserted, and past a mild steel or 316 stainless steel heat exchanger $ube contained in a Plexiglas (trademark of Rohm and Haas Co.) block. The heat exchanger tube is fitted with an electrical heater so that the heat load on the tube can be varied and controlled in the 0 to 16,000 BTU/ft2/
hour range. The water velocity passed the corrosion coupons and heat exchanger tubes is equivalent at any given flow rate and can be controlled anywhere from 0 to 4.5 ft/sec.
The pH and temperature of the recirculating water are automatically controlled. The treated water is prepared by chemical addition to deionized water. Provisions for continuous makeup and blowdown are made by pumpins~ fresh treated water from supply tanks to the sump of the unit, with overflow from the sump serving as blowdown. The total system volume is about 12 liters. Tables 2 and 3 summarize the results of tests run at different conditions of M alkalinity.
~3~3 Dynamic Testinq Conditions:
M - Alk = 250 600 ppm Ca2~ as CaO03 pH = 8.5 LSI = 2.2 2 200 ppm Mg2+ as CaC03 Heat Flux = 15600 Btu/hr.ft 406 ppm NaHC03 Sol. velocity = 4 gpm 50 ppm SiO2 Temperature = 120F
3 ppm TTA 7 days run Heat ~ransfer Corrosion Treatment Surface Resultson LCS (m 15 ppm PESA Admiralty Clean NO LOS
15 ppm PESA + 15 ppm AA/AOP " Heavy Deposit 15 ppm PESA + ~5 ppm Coag 106 " Heavy Deposit "
15 15 ppm PESA + 15 ppm AA/AHPSE I " Heavy Deposit "
15 ppm PESA ~ 15 ppm AA/AHPSE II " Heavy Deposit 15 ppm PESA + 15 ppm AA/AOP
+ 2 ppm N;2+ " Heavy Deposit "
15 ppm PESA + 15 ppm AA/AOP
+ 2 ppm oo2+ " Heavy Deposit 15 ppm PESA + 15 ppm M/AOP
~ 2 ppm Mn~+ " Heavy Deposit 15 ppm PESA + 15 ppm AA/AOP
t 2 ppm Mo " Heavy Deposit "
2~3~
TABLE 2 LCont'd) Heat Transfer Corrosion Treakment Surface Resultson LCS (mpY) 15 ppm PESA + 15 ppm AA/AOPAdmiralty 5+ 1 ppm La3t Clean NO LCS
15 ppm PESA + 15 ppm M/AHPSE I
+ 1 ppm La3+ " Clean "
15 ppm PESA (2 days run) LCS H~avy Corrosion 5.14 15 ppm PESA + 2 ppm Zn2~ LCS Slight Deposit0.20 1025 ppm PESA + 2 ppm Zn2+ LCS Moderate Deposit 0.50 15 ppm PESA ~ 5 ppm M/AHPSE I
+ 1 ppm La3+ LCS Clean 0.64 10 ppm PESA + 5 ppm AA/AHPSE I
+ 1 ppm La3+ LCS Clean 0.64 15 ppm PESA ~ 5 ppm AA/AHPSE I
+ 1 ppm Nd3+ LCS Clean 1.00 All AA/AHPSE concentrations are given as active polymer Coag 106 is a polyacrylic acid available from Betz Labs of Trevose, PA
~14- 2~ 5~
~i _mic Testinq Conditions:
M - Alk = 400 450 ppm Ca2+ as CaC03 pH = 8.8 LSI = 2.6 200 ppm Mg2+ as CaC03 Heat Flux = 8000 Btu/hr.ft2 580 ppm NaHC03 Sol. velocity = 4 gpm 300 ppm SO~ Temperature = 120F
50 ppm SiO~ 7 days run 3 ppm TTA LCS Heat Transfer Surface Corrosion Rate on LCS Coupons Treatment _ Results(mpy~ _ _ 25 ppm PESA + 10 ppm AA/AOHBA Film of deposit 0.85 + 2 ppm 2n2+ Moderate Corrosion 25 ppm PESA + 10 ppm M/AHPSE IIFilm of deposit 0~20 + 2 ppm Zn2+ High Turbidity 25 ppm PESA + 10 ppm M/AHPSE I Heavy Deposit 9.60 (4 days run) and Corrosion 25 ppm PESA + 10 ppm AA/AHPSE INo scale on tube 0.57 + 2 ppm Zn2+ High turbidity 25 ppm PESA + 10 ppm AA/AHPSE I Clean 0.43 + 1 ppm La3+
15 ppm PESA ~ 5 ppm AA/AHPSE I Clean 0.58 + 1 ppm La3+
25 ppm PESA + 5 ppm AA/AHPSE I Clean 0.53 + 1 ppm P~3+
All M /AHPSE concentrations are gi~en as active polymer.
M/AOHBA is acrylic acid/allyloxy-3-hydroxybutanoic acid.
2~83~L~3 ,5 As can be seen from Tables 2 and 3~ the combination of the.present invention inhibits deposition on the heat transfer surfaces as well as inhibiting corrosion on low carbon steel.
Ions such as cobalt, nickel, manganese and molybdate failed to produce the results of the present invention.
While this invention has been described with respect to particular embodiments thereof, it is apparent that numerous other forms and modifications of the invention will be obvious to those skilled in the art. The appended claims and this invention generally should be construed to cover all such obvious forms and modifications which are within the true scope and spirit of the present inYention.
15 ppm PESA + 15 ppm AA/AOP " Heavy Deposit 15 ppm PESA + ~5 ppm Coag 106 " Heavy Deposit "
15 15 ppm PESA + 15 ppm AA/AHPSE I " Heavy Deposit "
15 ppm PESA ~ 15 ppm AA/AHPSE II " Heavy Deposit 15 ppm PESA + 15 ppm AA/AOP
+ 2 ppm N;2+ " Heavy Deposit "
15 ppm PESA + 15 ppm AA/AOP
+ 2 ppm oo2+ " Heavy Deposit 15 ppm PESA + 15 ppm M/AOP
~ 2 ppm Mn~+ " Heavy Deposit 15 ppm PESA + 15 ppm AA/AOP
t 2 ppm Mo " Heavy Deposit "
2~3~
TABLE 2 LCont'd) Heat Transfer Corrosion Treakment Surface Resultson LCS (mpY) 15 ppm PESA + 15 ppm AA/AOPAdmiralty 5+ 1 ppm La3t Clean NO LCS
15 ppm PESA + 15 ppm M/AHPSE I
+ 1 ppm La3+ " Clean "
15 ppm PESA (2 days run) LCS H~avy Corrosion 5.14 15 ppm PESA + 2 ppm Zn2~ LCS Slight Deposit0.20 1025 ppm PESA + 2 ppm Zn2+ LCS Moderate Deposit 0.50 15 ppm PESA ~ 5 ppm M/AHPSE I
+ 1 ppm La3+ LCS Clean 0.64 10 ppm PESA + 5 ppm AA/AHPSE I
+ 1 ppm La3+ LCS Clean 0.64 15 ppm PESA ~ 5 ppm AA/AHPSE I
+ 1 ppm Nd3+ LCS Clean 1.00 All AA/AHPSE concentrations are given as active polymer Coag 106 is a polyacrylic acid available from Betz Labs of Trevose, PA
~14- 2~ 5~
~i _mic Testinq Conditions:
M - Alk = 400 450 ppm Ca2+ as CaC03 pH = 8.8 LSI = 2.6 200 ppm Mg2+ as CaC03 Heat Flux = 8000 Btu/hr.ft2 580 ppm NaHC03 Sol. velocity = 4 gpm 300 ppm SO~ Temperature = 120F
50 ppm SiO~ 7 days run 3 ppm TTA LCS Heat Transfer Surface Corrosion Rate on LCS Coupons Treatment _ Results(mpy~ _ _ 25 ppm PESA + 10 ppm AA/AOHBA Film of deposit 0.85 + 2 ppm 2n2+ Moderate Corrosion 25 ppm PESA + 10 ppm M/AHPSE IIFilm of deposit 0~20 + 2 ppm Zn2+ High Turbidity 25 ppm PESA + 10 ppm M/AHPSE I Heavy Deposit 9.60 (4 days run) and Corrosion 25 ppm PESA + 10 ppm AA/AHPSE INo scale on tube 0.57 + 2 ppm Zn2+ High turbidity 25 ppm PESA + 10 ppm AA/AHPSE I Clean 0.43 + 1 ppm La3+
15 ppm PESA ~ 5 ppm AA/AHPSE I Clean 0.58 + 1 ppm La3+
25 ppm PESA + 5 ppm AA/AHPSE I Clean 0.53 + 1 ppm P~3+
All M /AHPSE concentrations are gi~en as active polymer.
M/AOHBA is acrylic acid/allyloxy-3-hydroxybutanoic acid.
2~83~L~3 ,5 As can be seen from Tables 2 and 3~ the combination of the.present invention inhibits deposition on the heat transfer surfaces as well as inhibiting corrosion on low carbon steel.
Ions such as cobalt, nickel, manganese and molybdate failed to produce the results of the present invention.
While this invention has been described with respect to particular embodiments thereof, it is apparent that numerous other forms and modifications of the invention will be obvious to those skilled in the art. The appended claims and this invention generally should be construed to cover all such obvious forms and modifications which are within the true scope and spirit of the present inYention.
Claims (4)
1. A method of increasing the scale control activity of polyepoxysuccinic acid when employed in combination with a copolymer of acrylic acid in an aqueous system which comprises adding a sufficient amount for the purpose of a lanthanide ion to the aqueous system.
2. A method of increasing the scale inhibiting activity of polyepoxysuccinic acid in aqueous systems in the presence of an acrylic acid copolymer which comprises adding a sufficient amount for the purpose of a lanthanide ion to the aqueous system.
3. A method of inhibiting the deposition of scale in aqueous systems by adding a polyepoxysuccinic acid of the general formula wherein n ranges from about 2 to 50, M is hydrogen or a water soluble cation and R is hydrogen, C 1 - 4 alkyl or C 1 - 4 substituted alkyl in combination with an acrylic acid copolymer which exhibits a decreased dispersant activity in the presence of polyepoxysuccinic acid comprising adding a lanthanide ion in an amount sufficient to inhibit said decreased dispersant activity.
4. A method of lnhibiting the depositinn of scale in aqueous systems by adding a polyepoxysuccinic acid of the general formula wherein n ranges from about 2 to about 50, M is hydrogen or a water soluble cation and R is hydrogen, C 1 - 4 alkyl or C 1 - 4 substituted alkyl in combination with an acrylic acid copolymer which causes a decrease in efficiency of the polyepoxysuccinic acid for scale control purposes which comprises adding a lanthanide ion in an amount sufficient to inhibit the decrease in polyepoxysuccinic acid scale control efficiency caused by said acrylic acid copolymer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/827,246 US5248438A (en) | 1992-01-28 | 1992-01-28 | Methods of controlling scale formation in aqueous systems |
| US07/827,246 | 1992-01-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2083453A1 true CA2083453A1 (en) | 1993-07-29 |
Family
ID=25248705
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002083453A Abandoned CA2083453A1 (en) | 1992-01-28 | 1992-11-20 | Methods of controlling scale formation in aqueous systems |
Country Status (2)
| Country | Link |
|---|---|
| US (2) | US5248438A (en) |
| CA (1) | CA2083453A1 (en) |
Cited By (1)
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| CN108164010A (en) * | 2017-12-29 | 2018-06-15 | 南京华洲新材料有限公司 | A kind of corrosion inhibiting and descaling agent and preparation method thereof |
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| US5368740A (en) * | 1993-04-23 | 1994-11-29 | Betz Paperchem, Inc. | Methods of controlling scale formation in the presence of metal ions in aqueous systems |
| US5378372A (en) * | 1993-06-09 | 1995-01-03 | Betz Laboratories, Inc. | Control of scale formation in aqueous systems |
| US5518629A (en) * | 1993-07-29 | 1996-05-21 | Betz Laboratories, Inc. | Methods for controlling scale formation in acqueous systems |
| US5326478A (en) * | 1993-07-29 | 1994-07-05 | Betz Laboratories, Inc. | Methods for controlling scale formation in aqueous systems |
| US5616278A (en) * | 1993-08-13 | 1997-04-01 | Betzdearborn Inc. | Inhibition of scale and corrosion in aqueous systems |
| US5871691A (en) * | 1993-08-13 | 1999-02-16 | Betzdearborn Inc. | Inhibition of corrosion in aqueous systems |
| US5575920A (en) * | 1994-03-11 | 1996-11-19 | Betzdearborn Inc. | Method of inhibiting scale and controlling corrosion in cooling water systems |
| CA2143405C (en) * | 1994-03-11 | 2005-12-13 | Donald T. Freese | Method of inhibiting scale and controlling corrosion in cooling water systems |
| US5486294A (en) * | 1994-09-30 | 1996-01-23 | Betz Laboratories, Inc. | Method of inhibiting barium sulfate and strontium sulfate scale at low pH |
| US5866032A (en) * | 1995-11-01 | 1999-02-02 | Betzdearborn Inc. | Composition for controlling scale formation in aqueous systems |
| US5705077A (en) * | 1996-01-31 | 1998-01-06 | Betzdearborn Inc. | Method of controlling fluoride scale formation in aqueous systems |
| US6312604B1 (en) * | 1998-10-23 | 2001-11-06 | Zodiac Pool Care, Inc. | Lanthanide halide water treatment compositions and methods |
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| US8178353B2 (en) * | 2007-05-31 | 2012-05-15 | General Electric Company | Method for determination of polymer concentration in water systems |
| CN100509652C (en) * | 2007-06-15 | 2009-07-08 | 武汉金坡化工科技有限公司 | No-phosphate corrosion and scale inhibitor and application thereof |
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| CN101565244B (en) * | 2008-04-23 | 2011-11-09 | 北京合创同盛科技有限公司 | Composition for water treatment |
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| CN101565243B (en) * | 2008-04-23 | 2011-11-09 | 北京合创同盛科技有限公司 | Composition containing polyepoxysuccinic acid salt |
| CN101811000B (en) * | 2009-02-25 | 2011-11-09 | 北京合创同盛科技有限公司 | Reverse osmosis membrane scale inhibitor |
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| CN102452721A (en) * | 2010-10-20 | 2012-05-16 | 中国石油化工股份有限公司 | Phosphorus-free composite scale-inhibiting corrosion-retarding agent and application thereof in water treatment |
| WO2012083496A1 (en) * | 2010-12-22 | 2012-06-28 | General Electric Company | Methods of removing microbes from surfaces |
| CN102730848B (en) * | 2011-04-02 | 2014-12-31 | 中国石油化工股份有限公司 | Composite anti-incrustation corrosion inhibiter and its application in water treatment |
| US9233863B2 (en) | 2011-04-13 | 2016-01-12 | Molycorp Minerals, Llc | Rare earth removal of hydrated and hydroxyl species |
| CN103183789B (en) * | 2011-12-28 | 2015-12-02 | 康吉诺（北京）科技有限公司 | Nano heavy calcium carbonate disperse and grind aid stopper and its preparation method and application |
| CN102730851B (en) * | 2012-07-11 | 2013-09-11 | 成都润兴消毒药业有限公司 | Water treatment medicament with functions of inhibiting corrosion and scale and killing microbes |
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| CN106757047A (en) * | 2016-11-10 | 2017-05-31 | 武汉钢铁股份有限公司 | A kind of environmentally friendly corrosion inhibitor of sea water |
| EP3585857A1 (en) * | 2017-02-27 | 2020-01-01 | General Electric Company | Scale inhibition in high pressure and high temperature applications |
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| CN112607874A (en) * | 2020-12-25 | 2021-04-06 | 广州市粤新工程技术有限公司 | Green environment-friendly corrosion and scale inhibitor |
| CN113432106A (en) * | 2021-06-30 | 2021-09-24 | 新疆百建安环保科技有限责任公司 | Cleaning and descaling agent and online cleaning process for high-pressure steam injection boiler of oil field |
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| GB8324717D0 (en) * | 1983-09-15 | 1983-10-19 | British Petroleum Co Plc | Inhibiting corrosion in aqueous systems |
| US4931188A (en) * | 1983-10-26 | 1990-06-05 | Betz Laboratories, Inc. | Polymers for boiler water treatment |
| US4872995A (en) * | 1983-10-26 | 1989-10-10 | Betz Laboratories, Inc. | Method for calcium oxalate scale control |
| US4941979A (en) * | 1989-02-08 | 1990-07-17 | Betz Laboratories, Inc. | Method of stabilizing manganese in aqueous systems |
| US5207919A (en) * | 1990-04-16 | 1993-05-04 | Baker Hughes Incorporated | Metal ion complexes for use as scale inhibitors |
| US5057228A (en) * | 1990-04-16 | 1991-10-15 | Baker Hughes Incorporated | Metal ion complexes for use as scale inhibitors |
| US5147555A (en) * | 1990-05-04 | 1992-09-15 | Betz Laboratories, Inc. | Methods of controlling scale formation in aqueous systems |
| US5062962A (en) * | 1990-05-04 | 1991-11-05 | Betz Laboratories, Inc. | Methods of controlling scale formation in aqueous systems |
| US5130052A (en) * | 1991-10-24 | 1992-07-14 | W. R. Grace & Co.-Conn. | Corrosion inhibition with water-soluble rare earth chelates |
-
1992
- 1992-01-28 US US07/827,246 patent/US5248438A/en not_active Expired - Fee Related
- 1992-11-20 CA CA002083453A patent/CA2083453A1/en not_active Abandoned
-
1993
- 1993-03-29 US US08/038,777 patent/US5342540A/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108164010A (en) * | 2017-12-29 | 2018-06-15 | 南京华洲新材料有限公司 | A kind of corrosion inhibiting and descaling agent and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| US5248438A (en) | 1993-09-28 |
| US5342540A (en) | 1994-08-30 |
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