CA1158595A - Scale control for sea water evaporators using an acrylic acid methyl acrylate copolymer - Google Patents
Scale control for sea water evaporators using an acrylic acid methyl acrylate copolymerInfo
- Publication number
- CA1158595A CA1158595A CA000361372A CA361372A CA1158595A CA 1158595 A CA1158595 A CA 1158595A CA 000361372 A CA000361372 A CA 000361372A CA 361372 A CA361372 A CA 361372A CA 1158595 A CA1158595 A CA 1158595A
- Authority
- CA
- Canada
- Prior art keywords
- acrylic acid
- methyl acrylate
- sea water
- acid methyl
- acrylate copolymer
- 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.)
- Expired
Links
Landscapes
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Process for evaporating saline waters comprising treating the water with from .1 - 3 ppm of an alkali metal or ammonium salt of a copolymer of acrylic acid and methyl acrylate having a weight ratio of from 3 - 4:1 and having a molecular weight within the range of 1000 - 3000 and then evaporating said water.
Process for evaporating saline waters comprising treating the water with from .1 - 3 ppm of an alkali metal or ammonium salt of a copolymer of acrylic acid and methyl acrylate having a weight ratio of from 3 - 4:1 and having a molecular weight within the range of 1000 - 3000 and then evaporating said water.
Description
9~
INTRODUCTION
Evaporation of sea water and other naturally occurring saline waters gives rise to the formation of scale deposits of low thermal conductivity on the heat transfer surfaces of the distillation plant. The heat transfer coefficients are thereby reduced, leading to deterioration of plant performance and necessitating the eventual shutdown of the plant for cleaning. Although several methods are in use for the control of alkaline scales, calcium sulfate and other scaling constituents normally found in saline waters, scaling considerations still set an upper limit on the brine boiling temperature and concentration factor, and hence on plant performance.
In evaporators, scale may be formed whenever scale-forming compounds are present in the feed water, but the type and composition of the scale may vary. For example, when evaporation of sea water takes place under reduced pressure at boiling temperatures below about 180F, the principal scaling phase is calcium carbonate; at higher temperatures it is primarily magnesium hydroxide in the form of brucite, but calcium sulfate scales may be formed at all temperatures if the brine concentration is sufficiently high.
THE INVENTION
Process for evaporating saline waters comprising treating the water with from .1 - 3 ppm of an alkali metal or ammonium salt of a copolymer of acrylic acid and methyl acrylate having a weight ratio of from 3 - 4:1 and having a molecular weight within the range of 1000 - 3000, preferably about 2400, and then evaporating said water.
To illustrate the advantage of the invention over other acrylic acid polymers and copolymers which have been suggested by the prior art as ~cale inhibitors, the following activity test was used.
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S~ , Activity Test - CaCO3 Scale Inhibition in Sea Water A Procedure 1. 500 g. of synthetic sea water ~2) is concentrated to a 1.5 salt concentration (333.33 g.) in beakers using a magnetic stirrer at 95C and atmospheric pressure.
INTRODUCTION
Evaporation of sea water and other naturally occurring saline waters gives rise to the formation of scale deposits of low thermal conductivity on the heat transfer surfaces of the distillation plant. The heat transfer coefficients are thereby reduced, leading to deterioration of plant performance and necessitating the eventual shutdown of the plant for cleaning. Although several methods are in use for the control of alkaline scales, calcium sulfate and other scaling constituents normally found in saline waters, scaling considerations still set an upper limit on the brine boiling temperature and concentration factor, and hence on plant performance.
In evaporators, scale may be formed whenever scale-forming compounds are present in the feed water, but the type and composition of the scale may vary. For example, when evaporation of sea water takes place under reduced pressure at boiling temperatures below about 180F, the principal scaling phase is calcium carbonate; at higher temperatures it is primarily magnesium hydroxide in the form of brucite, but calcium sulfate scales may be formed at all temperatures if the brine concentration is sufficiently high.
THE INVENTION
Process for evaporating saline waters comprising treating the water with from .1 - 3 ppm of an alkali metal or ammonium salt of a copolymer of acrylic acid and methyl acrylate having a weight ratio of from 3 - 4:1 and having a molecular weight within the range of 1000 - 3000, preferably about 2400, and then evaporating said water.
To illustrate the advantage of the invention over other acrylic acid polymers and copolymers which have been suggested by the prior art as ~cale inhibitors, the following activity test was used.
~.
,, -~ , .
,.~
.,, ~
- ' ~, ,, ' : -:
S~ , Activity Test - CaCO3 Scale Inhibition in Sea Water A Procedure 1. 500 g. of synthetic sea water ~2) is concentrated to a 1.5 salt concentration (333.33 g.) in beakers using a magnetic stirrer at 95C and atmospheric pressure.
2. Concentrated solution is filtered hot through matched weight milli-pore filters. Filters are dried for 30 min. at 105C and weighed to an ac-curacy of 0.1 mg. Beakers also are allowed to cool.
3. Deposit on beakers is dissolved in about lO0 g. deionised water and 7 g. 10% by weight HNO3. After mixing to insure dissolution, the solution is neutralized with 2.5 g. of 10% by weight NaOH (pH 6 - 7) and diluted to 150 g.
with deionised water. The solution is titrated for total dissolved hardness and dissolved CaCO3 hardness.
with deionised water. The solution is titrated for total dissolved hardness and dissolved CaCO3 hardness.
4. Precipitate on filter paper is dissolved in ~-200 g. deionised water and 14 g. 10% by weight HNO3, neutralized with 5.0 g 10% by weight NaOH and diluted to 250 g. with deionised water. The solution is titrated for total dissolved hardness and dissolved CaCO3 hardness ~same as Step 3).
Using the above test method, the results of Table I were obtained:
TABLE I
Percent CaCO
DosageInhibition vs.
Composition Peak MW Polymer, ppm Control M/MA' 5000-9000 077 79 .088 95 . 099 99 AA/MA' _ 2400 .050 99 .070 99 . 090 100 AA ~ 2600 .072 78 .081 70 .090 98 'Weight ratio of acrylic acid to methyl acrylate 3.75:1 Acids are in sodium salt form.
11$t~5~3~
The significance of Table I shows the 2400 MW copolymer still has excellent activity at .05 ppm active, whereas, the acrylic and homopolymer and higher molecular weight copolymer start to lose activity at ~ .08 ppm.
This is ~ 50% increase in activity.
Using the above test method, the results of Table I were obtained:
TABLE I
Percent CaCO
DosageInhibition vs.
Composition Peak MW Polymer, ppm Control M/MA' 5000-9000 077 79 .088 95 . 099 99 AA/MA' _ 2400 .050 99 .070 99 . 090 100 AA ~ 2600 .072 78 .081 70 .090 98 'Weight ratio of acrylic acid to methyl acrylate 3.75:1 Acids are in sodium salt form.
11$t~5~3~
The significance of Table I shows the 2400 MW copolymer still has excellent activity at .05 ppm active, whereas, the acrylic and homopolymer and higher molecular weight copolymer start to lose activity at ~ .08 ppm.
This is ~ 50% increase in activity.
Claims (2)
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Process for evaporating saline waters comprising treating the water with from .1 - 3 ppm of an alkali metal or ammonium salt of a copolymer of acrylic acid and methyl acrylate having a weight ratio of from 3 - 4:1 and having a molecular weight within the range of 1000 - 3000 and then evaporat-ing said water.
2. The method of Claim 1 where the molecular weight of the copolymer is about 2400.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US8199779A | 1979-10-04 | 1979-10-04 | |
| US81,997 | 1979-10-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1158595A true CA1158595A (en) | 1983-12-13 |
Family
ID=22167738
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000361372A Expired CA1158595A (en) | 1979-10-04 | 1980-10-02 | Scale control for sea water evaporators using an acrylic acid methyl acrylate copolymer |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1158595A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104418394A (en) * | 2013-08-20 | 2015-03-18 | 中国石油化工股份有限公司 | Additive used in evaporation and concentration of cyclohexanone saponified solution |
-
1980
- 1980-10-02 CA CA000361372A patent/CA1158595A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104418394A (en) * | 2013-08-20 | 2015-03-18 | 中国石油化工股份有限公司 | Additive used in evaporation and concentration of cyclohexanone saponified solution |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |