Method for controllong scale formation and deposition in aquesous systems

Description of the invention

The present invention relates to a composition and a method for inhibiting scale formation and deposition in water systems such as cooling, boiler and wet gas dedusting systems; pulp and paper manufacturing processes; in the pretreatment of metals; as rheology modifiers for concrete and cement additives; as cleaning agents for membranes; and as hydrophilic modifier ingredients in personal care, cosmetic and pharmaceutical formulations. The novel polymeric compositions comprise water-soluble or water-dispersible copolymers of sulfate, phosphate, phosphite or carboxyl-terminated poly (oxyalkylene) allyl ethers.

Corrosion and limescale problems and associated effects have been disrupting water systems for years. For example, there is a tendency for limescale to build up on the inner walls of various water systems, such as boiler and cooling systems, which significantly reduces the operational efficiency of the system.

Deposits in pipes, heat exchangers, etc., can be due to several reasons. For example, the precipitation of calcium carbonate, calcium sulfate and calcium phosphate in the water system leads to the accumulation of these limescale compounds along or around the metallic surfaces that contact the flowing water circulating in the system. Thus, the heat transfer functions in a particular system are significantly inhibited.

On the other hand, corrosion is a decomposing electrochemical reaction of a metal due to the action of the environment. Simply put, it is the return of refined metals to their natural state. For example, the iron ore is iron oxide. Iron ore is refined to steel. When the steel corrodes, iron oxide is formed which, if left untended, can damage or destroy the metal, causing the affected water system to shut down for necessary repairs.

Typically, in aqueous cooling systems, the formation of calcium sulfate, calcium phosphate, and calcium carbonate, among others, has proved detrimental to the overall cooling performance of the water system. Recently, due to the widespread use of refrigeration systems using high levels of orthophosphate to aid passivation of the metal surface in contact with an aqueous system, it has become very important to control the crystallization of calcium phosphate so that relatively high levels of orthophosphate can be maintained in the system to achieve the desired passivation without contamination or limiting the heat transfer functions that typically result from calcium phosphate deposition.

Silica (SiO2) is present in most natural waters. As these waters circulate through the cooling column, the silica content increases and often this content reaches levels at which precipitation occurs. Sometimes precipitation occurs by polymerizing the silica itself, resulting in silica gel. For this to occur, a relatively high concentration of SiO2 is needed, typically above about 200 ppm. However, when certain cations are present, silica can precipitate at much lower concentrations. The cations supporting the precipitation of silica include, but are not limited to, Al³⁺, Mg²⁺, Zn²⁺ and Fe³⁺. Aluminum is very slightly soluble in water and precipitates easily on cooling the water. For example, if aluminum gets into a cooling system (such as a transfer system), it can cause serious precipitation problems. One such problem is the precipitation of phosphate compounds that may act as a corrosion inhibitor. Such deposits can be troublesome due to both deposition and corrosion effects.

Although steam generation systems are quite different from cooling systems, the common problem of sludge formation is also present in them.

As detailed in Betz Handbook of Industrial Water Conditioning, Issue 9, 1991, Betz Laboratories Inc., Trevose, Pa, pp. 96-104, the formation of limescale and sludge on the boiler heating surfaces is a serious problem encountered in steam production. Although current industrial steam generation systems use complex external treatment of the boiler feedwater, such as e.g. coagulation, filtration, and water softening prior to its introduction into the boiler system, these operations are only partially effective. In all cases, the external treatment as such does not provide adequate treatment because the sludge, sludge and hardness ions are not treated and are possibly fed into the steam generation system.

In addition to the problems caused by sludge, sludge or runny nose, the industry also has to combat limescale deposits. Although external treatment is used specifically to attempt to remove calcium and magnesium from the feed water, scale formation always occurs due to residual hardness, i.e. the presence of calcium and magnesium salts. In accordance with this, an internal treatment is necessary, i.e. treatment of the system feedwater to prevent, reduce and / or delay the formation of limescale compounds and their deposition. In addition to magnesium and calcium carbonates which are problematic due to limescale, high concentrations of phosphate, sulphate and silicate ions, either naturally occurring or introduced for other purposes, are causing problems because the calcium and magnesium present and any iron or copper react and they deposit as limescale. It is clear that the limescale deposition on the structural parts of the steam generating system results in poorer circulation and lower heat transfer efficiency, resulting in an overall reduction in efficiency.

U.S. Patent Specification US No. 4,471,100 to Tsubakimoto et al. Discloses a copolymer consisting of maleic acid repeating units and poly (oxy) alkylene glycol monoallyl ether, useful as a dispersant for cement and paint, and as a limescale inhibitor for calcium carbonate.

U.S. Patents US No. 5,180,498; 5292379; and 5,391,238 to Chen et al. disclose copolymers of acrylic acid and polyethylene glycol allyl ether for boiler water treatment and metal pretreatment.

U.S. Patent Specification US U.S. Patent 5,362,324 teaches poly (oxy) ethylene glycol monomethyl ether methacrylate terpolymers and poly (oxy) propylene glycol dimethacrylate for use as a superplasticizer. U.S. Patent Specification US No. 5,661,206 and European Patent No. 44,87717 disclose a similar technology but using diepoxide-based compounds as crosslinkers. Japanese Patent Nos. 93660, 226757 and 212152 disclose terpolymers of acrylic acid with sodium methallyl sulfonate and methoxy polyethylene glycol monomethacrylate for use as a superplasticizer.

U.S. Patent Specification US No. 5,575,920 to Freese et al. Discloses terpolymers of acrylic acid, allyloxy-2-hydroxypropylsulfonic acid ester (AHPS) and poly (oxy) ethylene glycol allyl ether for the treatment of cooling water as inhibitors of calcium phosphate formation.

U.S. Patent Specification US No. 4,944,885 discloses copolymers used to inhibit corrosion and scale.

U.S. Patent Specification US No. 4,500,693 discloses water-soluble copolymers containing branched chain polyether substituents for use as anti-limescale agents and as pigment dispersants.

U.S. Patent Specification US No. 3,875,202 to Steckler discloses polymerizable ammonium and alkali metal salts of monoethylenically unsaturated alcohol sulfates with 3 to 12 carbon atoms and alkenoxylated adducts of such alcohols. The polymerizable monomers are useful as co-polymerizable surfactants for self-stabilizing latexes and as comonomers in copolymerization with other monomers for the preparation of co- or terpolymeric films and fibers, especially as receptors for basic dyes and for imparting antistatic properties. This patent discloses monomers such as vinyl chloride, ethyl acrylate, 2-ethylhexyl acrylate, vinyl acetate, and N-methyl acrylamide for copolymerization with the ammonium salt of monoethylenically unsaturated alcohol sulfate. The disclosed copolymers are insoluble in water.

U.S. Patent Specification US No. 5,705,665 to Ichinohe et al. Relates to organic silicon compounds having as one component an ethoxylated allyl alcohol with an alkali metal salt of a sulfonate group in the molecule. The resulting compound is useful as a surface treatment agent and modifier for an inorganic substance. The disclosed copolymers are not water-soluble or dispersible.

The invention relates to a composition comprising:

a water-soluble or water-dispersible polymer of formula (I):

PL 204 918 B1

<img file="PL204918B1_D0001.tif" />

wherein E is the repeating unit remaining after polymerization of one or more ethylenically unsaturated compounds selected from: carboxylic acid, sulfonic acid, phosphonic acid or an amide form thereof or mixtures thereof; R1 is H or lower (C1-C4) alkyl; G is -CH2- or -CHCH3-;

R2 is - (CH2-CH2-O) n- or - (CH2-CHCH3-O) m-; in which n and m range from 1 to 100; X is SO3, PO3 or COO; Z is H, or a water-soluble cationic group selected from Na, K, Ca or NH4; F is a repeating unit with the formula:

<img file="PL204918B1_D0002.tif" />

where R4 is H or lower (C1-C4) alkyl, R5 is hydroxy substituted alkyl or alkylene of 1 to 6 carbon atoms; wherein the ratio of c: d: e is from 20: 10: 1 to 1: 1:20 or e is zero and the ratio of c: d is from 30: 1 to 1:20.

Preferably, the ethylenically unsaturated compound is one or more of: acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, maleic acid or anhydride, fumaric acid, itaconic acid, styrenesulfuric acid. , vinylsulfonic acid, isopropenylphosphonic acid, vinylphosphonic acid, vinylidenediphosphonic acid, 2-acrylamido-2-methylpropanesulfonic acid, or mixtures thereof.

Preferably, the molecular weight Mw is in the range of 1,000-10,000,000, more preferably the molecular weight Mw is in the range of 1,000 to 50,000, most preferably the molecular weight Mw is in the range of 1,500 to 25,000.

Preferably, n is greater than 10.

Preferably, the water-soluble or water-dispersible polymer has the formula:

<img file="PL204918B1_D0003.tif" />

Where n is in the range 1-100, Z is a hydrogen atom or a water-soluble cation selected from the group consisting of Na, K, Ca or NH4 or mixtures thereof, and the c: d ratio is in the range from 30: 1 to 1:20.

Preferably, the water-soluble or water-dispersible polymer has the formula:

<img file="PL204918B1_D0004.tif" />

where n is in the range 1-100, Z is a hydrogen atom or a water-soluble cation selected from the group consisting of Na, K, Ca or NH4 or mixtures thereof, and the value of the c: d ratio is in the range of 30 : 1 to 1:20.

Preferably the composition comprises at least one or more complementary agents.

The present invention relates to a method of inhibiting the formation and deposition of limescale substances on the exposed surfaces of a water system, in which a water-soluble or water-dispersible polymer of formula :

<img file="PL204918B1_D0005.tif" />

wherein E is the repeating unit remaining after polymerization of one or more ethylenically unsaturated compounds selected from: carboxylic acid, sulfonic acid, phosphonic acid or an amide form thereof or mixtures thereof; R1 is H or lower (C1-C4) alkyl; G is -CH2- or -CHCH3-;

R2 is - (CH2-CH2-O) n- or - (CH2-CHCH3-O) m, wherein n and m range from 1 to 100; X is SO3, PO3 or COO; Z is H, or a water-soluble cationic group selected from Na, K, Ca or NH4; F is a repeating unit with the formula:

<img file="PL204918B1_D0006.tif" />

Wherein R4 is H or lower (C1-C4) alkyl, R5 is hydroxy substituted alkyl or alkylene of 1 to 6 carbon atoms; wherein the ratio of c: d: e is from 20: 10: 1 to 1: 1:20 or e is zero and the ratio of c: d is from 30: 1 to 1:20.

Preferably, the ethylenically unsaturated compound is one or more of the following compounds: acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, maleic acid or anhydride, fumaric acid, itaconic acid , styrenesulfonic acid, vinylsulfonic acid, isopropenylphosphonic acid, vinylphosphonic acid, vinylidene diphosphonic acid, 2-acrylamido-2-methylpropanesulfonic acid or mixtures thereof.

Preferably, the molecular weight Mw is in the range of 1,000-10,000,000, more preferably the molecular weight Mw is in the range of 1,000 to 50,000, most preferably the molecular weight Mw is in the range of 1,500 to 25,000.

Preferably, n is greater than 10.

Preferably, the polymer is added to the aqueous system in an amount from 1 ppm to 100 ppm.

Preferably, the method is applied in an aqueous system that is a steam generation system.

Preferably, the method is applied in a water system that is a refrigerated water system.

Preferably, the method is applied in an aqueous system that is a gas scrubbing system.

Preferably, the water-soluble or water-dispersible polymer is added in conjunction with at least one or more complementary agents.

The meaning of E in formula I may include the repeating unit obtained after polymerization of carboxylic acid, sulfonic acid, phosphonic acid or their amide forms or mixtures thereof. Exemplary compounds include, but are not limited to, the repeating unit remaining after the polymerization of acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, maleic acid or anhydride, fumaric acid, itaconic acid , styrenesulfonic acid, vinylsulfonic acid, isopropenylphosphonic acid, vinylphosphonic acid, vinylidene diphosphonic acid, 2-acrylamido-2-methylpropanesulfonic acid and the like, and mixtures thereof. Water-soluble salt forms of these acids are also within the scope of this invention. More than one type of monomeric E unit may be present in the composition of the invention.

The subscripts c, d, and e in Formula I represent the molar ratio of the monomeric repeating unit. This ratio is not essential to the present invention as long as the resulting copolymer is water soluble or dispersible. The subscripts c and d are positive integers, while the subscripts e are a non-negative integer. Ie, c and d are integers from 1 or more while e can be 0,1,2 ... etc.

Polymerization of the copolymer and / or terpolymer may be carried out by solution, emulsion, micelle or suspension polymerization techniques. Conventional polymerization initiators such as persulfates, peroxides and azo initiators can be used. The polymerization can also be initiated by radiation or ultraviolet. Chain transfer agents such as alcohols, preferably isopropanol or allyl alcohol, amines or thio compounds can be used to regulate the molecular weight of the polymer. Branching agents such as methylenebisacrylamide or polyethylene glycol diacrylate and other multifunctional crosslinkers can be added. The resulting polymer can be isolated by precipitation or other well known techniques. If the polymerization is carried out in an aqueous solution, the polymer can simply be used in the form of an aqueous solution.

The molecular weight of the water-soluble copolymer of formula I is not critical but is preferably in the Mw range of about 1,000 to 1,000,000. The primary criterion is the water solubility or dispersibility of the polymer.

The compositions of the invention are effective in treating water in cooling water systems, boiler systems and steam generation systems as scale control agents and / or corrosion inhibitors. The appropriate concentration to be used will vary depending on the particular system for which treatment is desired, and will depend upon factors such as surface area exposed to corrosion, pH, temperature, amount of water, and the respective water concentrations of potential limescale components and sediment formers. In most cases, the compositions of the invention will be effective at levels of 0.1-500 parts per million parts of water, and preferably 1 to 100 parts per million of water, contained in the aqueous system to be treated. The compositions can be added directly to the desired aqueous system in an aqueous solution, either continuously or intermittently.

PL 204 918 B1

The use of the compositions according to the invention is not limited to any specific category of aqueous system. They are expected to inhibit the formation and deposition of limescale salts in any water system where this problem may occur. For example, in addition to boiler systems and water cooling systems, the compositions can also be effectively used in flushing systems and the like where corrosion and / or the formation and deposition of scale-forming salts is a problem. Other possible embodiments whereby the compositions of the invention may be used include seawater desalination plants, dust removal systems in the iron and steel industry, mine systems and geothermal systems. The compositions of the invention are also effective as scale and tar regulators in papermaking and pulp processes to prevent the formation of tar, calcium oxalate and barium sulfate. They can also be used as viscosity modifiers in mining and mineral processing to reduce the viscosity of suspensions.

Water-soluble or dispersible polymers can be used in conjunction with complementary agents to enhance corrosion inhibition and their scaling control properties. For example, the polymers can be used in combination with one or more compounds selected from the group consisting of inorganic phosphoric acids or their salts, phosphonic acid salts, organic phosphoric acid esters, and polyvalent metal salts or mixtures thereof. Such supplements may be added to the system under treatment in an amount from 1 to 500 ppm.

Examples of inorganic phosphoric acids include condensed phosphoric acids and their water-soluble salts. Examples of phosphoric acids include orthophosphoric acids, primary phosphoric acids, and secondary phosphoric acids and their salts. Examples of inorganic condensed phosphoric acids include polyphosphoric acids such as pyrophosphoric acid, tripolyphosphoric acid and the like, metaphosphoric acids such as trimetaphosphoric acid and tetrametaphosphoric acid and their salts.

Examples of other phosphoric acid derivatives that can be combined with the polymers in the composition of the invention include aminopolyphosphonic acids such as aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid and the like, methylenediphosphonic acid, hydroxyethylidene diphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid and the like. ., and their salts.

Exemplary organic acid phosphoric esters that can be combined with the polymers in the present invention include phosphoric acid esters of alkyl alcohols such as phosphoric acid methyl ester, phosphoric acid ethyl ester and the like, methyl cellosolve and ethyl cellosolve esters, and phosphoric acid esters. with polyoxyalkylated polyhydroxy compounds obtained by adding ethylene oxide to polyhydroxy compounds such as glycerol, mannitol, sorbitol, and the like. Other suitable organic phosphoric acid esters are esters of phosphoric acid with amino alcohols such as mono, di and triethanolamines. Water-soluble polymers can also be used in conjunction with molybdates such as sodium molybdate, potassium molybdate, lithium molybdate, ammonium molybdate, etc.

The polymers can be used in conjunction with still other complementary agents including corrosion inhibitors for iron, steel, copper, and copper or other metal alloys, conventional scaling and fouling inhibitors, metal ion sequestrants, and other common water treatment agents. Examples of other corrosion inhibitors include tungstate, nitrites, boranes, silicates, oxycarboxylic acids, amino acids, catechols, aminoaliphatic surfactants, benzotriazole, halogenated triazoles, and mercaptobenzothiazole. Other scaling and fouling inhibitors include lignin derivatives, tannic acids, starches, polyacrylic acids, and copolymers thereof including but not limited to acrylic acid / 2-acrylamido-2-methylpropanesulfonic acid and acrylic acid / allyloxy-2-acid. hydroxypropane-3-sulfonic, maleic acids and their copolymers, polyepoxysuccinic acids and polyacrylamides, etc. Examples of metal ion sequestrants include polyamines such as ethylenediamine, diethylenetriamine and the like, and polyaminocarboxylic acids such as nitrilotriacetic acid, ethylenediaminetetraacetic acid, and diethylenetriaminepentaacetic acid.

U.S. Patents US No. 4,659,481; 4,717,499; 4,759,851; 4,913,822 and 4,872,995, disclose the use of specific copolymers to treat cooling, boiler, steam generation and other water heat transfer systems to inhibit limescale deposition such as calcium phosphate, calcium phosphonate, calcium oxalate, iron oxide, zinc oxide, and silica. Based on the effectiveness of the scale control agents shown by the polymers in the compositions of the invention, it is believed that they could replace polymers.

Disclosed in the foregoing and other similar patents, yielding superior performance in a wide variety of water-based treatment applications.

The copolymers can be used alone or in combination with conventional cleaning agents such as surfactants, chelating agents, citric acid, phosphoric acid, and other common reagents used to remove sediment and prevent clogging of membranes used in microfiltration, ultrafiltration, and reverse osmosis.

The copolymers can also be used as superplasticizers or retarders with cementitious materials in construction applications. In addition, the polymers are useful as slurry viscosity modifiers in the mining and mineral processing and oil industries.

Example 1

Preparation of acrylic acid / allyl polyethoxylated (10) ammonium sulfate copolymer

A suitable reaction flask was equipped with a mechanical stirrer, thermometer, reflux condenser, nitrogen inlet, and two additional inlets for initiator and monomer solutions. The flask was charged with 73.5 g of deionized water and 58.5 g (0.1 mol) of allyl polyethoxylated (10) ammonium sulfate. With nitrogen flush, the solution was heated to 85 ° C. An initiator solution containing 2.2 g of 2,2'-azobis (2-amidinopropane) hydrochloride (Wako V-50, from Wako Chemical Company) was purged with nitrogen for ten minutes. The initiator solution and 21.6 g (0.3 mol) of acrylic acid were gradually added to the reaction flask over two hours. After the addition was complete, the solution was heated to 95 ° C and held at that temperature for 90 minutes. The reaction mixture was then cooled to below 40 ° C and a 50% caustic soda solution was added until the pH was 8-9. The structure of the obtained copolymer was confirmed by method C.¹³ NMR. The polymer solution was diluted to 30% solids and had a Brookfield viscosity of 48.6 mPa · s at 25 ° C.

Example 2

Preparation of acrylic acid / allyl polyethoxylated (10) ammonium sulfate copolymer

Using a procedure and apparatus similar to that described in the previous example, 147 g of deionized water and 61.9 g (0.11 mol) of allyl polyethoxylated (10) ammonium sulfate (DVP-010, from Bimax Inc.) were charged to the reaction flask. The solution was heated to 85 ° C. An initiator solution containing 1.9 g of sodium persulfate in water was introduced with nitrogen for ten minutes. The initiator solution and 22.9 g (0.32 mol) of acrylic acid were gradually added to the reaction flask over the course of two hours. After the addition was complete, the solution was heated to 95 ° C and held at that temperature for 90 minutes. The reaction mixture was cooled to below 40 ° C and a 50% caustic soda solution was added until the pH was 4-5. The structure of the obtained copolymer was confirmed by method C.¹³ NMR. The polymer solution was diluted to 30% solids and had a Brookfield viscosity of 13.0 cps at 25 ° C.

Example 3

Preparation of terpolymer acrylic acid / allylpolyethoxylated (10) ammonium sulfate / allyloxy-2-hydroxypropane-3-sulfonic acid

Using a procedure and apparatus similar to that described in Example 1, 84.7 g of deionized water, 21.8 g (0.1 mol) of allyloxy-2-hydroxypropane-3-sulfonic acid and 58.5 g (0.1 mol) of the monomer allyl polyethoxylated (10) ammonium sulfate was charged to the reaction flask. With nitrogen flush, the solution was heated to 85 ° C. An initiator solution of 2,2'-azobis (2-amidinopropane) hydrochloride and 21.6 g (0.3 mol) of acrylic acid were added to the reaction flask over 3.5 hours. After the addition was complete, the solution was heated to 95 ° C and held at that temperature for two hours. The reaction mixture was cooled and a 50% caustic soda solution was added until the pH was adjusted. The structure of the obtained copolymer was confirmed by method C.¹³ NMR. The polymer solution was diluted to 30% solids and had a Brookfield viscosity of 27.2 mPa · s at 25 ° C.

Example 4

Preparation of terpolymer acrylic acid / methacrylic acid / allyl polyethoxylated (10) ammonium sulphate

Using a procedure and apparatus similar to that described in Example 1, 109.7 g of deionized water, a mixture of 20.6 g of isopropyl alcohol and 58.5 g (0.1 mol) of ammonium sulfate allyl polyethoxylate monomer (10) was charged to the reaction flask. With nitrogen flush, the solution was heated to 85 ° C. A solution of sodium persulfate and 21.6 g (0.3 mol) of acrylic acid and 8.6 g

(0.1 mol) methacrylic acid was added separately to the reaction flask over two hours. After the addition was complete, the solution was heated to 95 ° C and held at that temperature for two hours. After the reaction is complete, the isopropyl alcohol will remove this from the solution before cooling it down and adjusting the pH. The structure of the obtained copolymer was confirmed by method C.¹³ NMR. The polymer solution was diluted to 25% solids and had a Brookfield viscosity of 21.0 mPa · s at 25 ° C.

Example 5

Preparation of the terpolymer acrylic acid / 2-acrylamido-2-methylpropanesulfonic acid / allyl polyethoxylated (10) ammonium sulfate

Using a procedure and apparatus similar to that described in Example 4, 127.9 g of deionized water, 20.5 g of isopropyl alcohol, and 58.5 g (0.1 mol) of ammonium sulfate allyl polyethoxylate monomer (10) were charged to the reaction flask. With a nitrogen purge, the solution was heated to 85 ° C. The sodium persulfate solution and a solution containing 21.6 g (0.3 mol) of acrylic acid and 20.7 g (0.1 mol) of 2-acrylamido-2-methylpropanesulfonic acid (AMPS®, ex Lubrizol Inc.) were added separately to the flask. reaction time for two hours. After the addition was complete, the solution was heated to 95 ° C and held at that temperature for two hours before cooling down and adjusting the pH. The structure of the obtained copolymer was confirmed by method C.¹³ NMR. The polymer solution was diluted to 25% solids and had a Brookfield viscosity of 17.0 cps at 25 ° C.

Example 6

Preparation of allyl polyethoxy phosphate (10)

A suitable reaction flask was equipped with a mechanical stirrer, thermometer and reflux condenser. 20 g of hydroxypolyethoxy (10) allyl ether (0.04 mol, AAE-10, from Bimax Inc.) was charged to the reactor. 6.16 g of phosphorus oxychloride (0.04 mol) was added dropwise to the reactor. The mixture was stirred vigorously for one hour, then heated to 50 ° C and held at that temperature for 4.5 hours. After cooling to ambient temperature, the reaction was quenched slowly by adding the mixture to water. The pH was adjusted to 4 with a caustic soda solution. Analysis C¹³ NMR indicated the presence of a phosphate ester.

Example 7

Manufacture of acrylic acid / polyethoxy allyl phosphate copolymer (10)

Using a procedure and apparatus similar to that described in Example 1, 41.3 g of deionized water and 60.3 g (0.05 mol) of 49.8% of allyl polyethoxy phosphate (10) of Example 6 were charged to the reaction flask. With nitrogen flush, the solution was heated to 85 ° C. A solution of 2,2'-azobis (2-amidinopropane) hydrochloride (1.07 g) and 10.7 g (0.147 mol) of acrylic acid were gradually added to the reaction flask over two hours. After the addition was complete, the solution was heated to 95 ° C and held at that temperature for 90 minutes before cooling down and adjusting the pH. The structure of the obtained copolymer was confirmed by method C.¹³ NMR. The polymer solution was diluted to 25% solids and had a Brookfield viscosity of 221.0 cps at 25 ° C.

Example 8

Manufacture of acrylic acid / allyl polyethoxy sulfate copolymer (10)

Using a procedure and apparatus similar to that described in Example 1, 58.6 g of deionized water, 58.6 g (0.1 mol) of allyl polyethoxy sulfate (10), and 0.8 g of allyl alcohol were charged to a reaction flask. With nitrogen flush, the solution was heated to 85 ° C. A solution of sodium persulfate (1.92 g) in 6.0 g of water and 21.6 g (0.147 mol) of acrylic acid was gradually added to the reaction flask over two hours. After the addition was complete, the solution was heated to 95 ° C and held at that temperature for 90 minutes before cooling down and adjusting the pH. The structure of the obtained copolymer was confirmed by method C.¹³ NMR. The polymer solution was diluted to 25% solids and had a Brookfield viscosity of 65.0 cps at 25 ° C.

Table 1 summarizes the composition and physical properties of the copolymers prepared according to the procedure described above. In Table 1, Examples 1-8 were carried out according to the respective description numbers above. Example 9 was carried out as described above for Examples 3-5 with modification of the comonomer molar ratio. Examples 10-20 were carried out as described in Examples 1 and 2 with modification of the comonomer molar ratio and molecular weight. Molecular weights were obtained by size exclusion chromatography using polyacrylic acid as standard.

PL 204 918 B1

Table 1

<td>Example</td><td>Polymer composition (Molar comonomer ratio)</td><td>% Solids</td><td>Brookfield viscosity iriPa ^ p</td><td>PH</td><td>Mass molecular (Mw)</td>

<td> 1</td><td>AA / APES (3/1)</td><td> 29,70</td><td> 48,6</td><td> 9,8</td><td> 18420</td>

<td> 2</td><td>AA / APES (3/1)</td><td> 29,23</td><td> 13,0</td><td> 4,2</td><td> 30670</td>

<td> 3</td><td>AA / AHPS / APES (3/1/1)</td><td> 30,10</td><td> 27,2</td><td> 8,3</td><td> 13100</td>

<td> 4</td><td>AA / MAA / APES (3/1/1)</td><td> 25,20</td><td> 21,0</td><td> 5,7</td><td> 19600</td>

<td> 5</td><td>AA / AMPS / APES (3/1/1)</td><td> 25,10</td><td> 17,0</td><td> 5,8</td><td> 17800</td>

<td> 6</td><td>AA / AAE-10 (3/1) phosphate</td><td> 25,7</td><td> 221,0</td><td> 6,5</td><td> -</td>

<td> 7</td><td>MAA / APES (6/1)</td><td> 30,75</td><td> 44,3</td><td> 8,3</td><td> 11,490</td>

<td> 8</td><td>AA / APES (3/1)</td><td> 25,7</td><td> 65,0</td><td> 7,4</td><td> 72100</td>

<td> 9</td><td>AA / AHPS / APES (6/1/1)</td><td> 30,47</td><td> 30,5</td><td> 9,4</td><td> 15790</td>

<td> 10</td><td>AA / AHPS / APES (3/1/1)</td><td> 30,11</td><td> 28,3</td><td> 8,0</td><td> 8252</td>

<td> 11</td><td>AA / APES (3/1)</td><td> 29,53</td><td> 13,2</td><td> 4,4</td><td> 13100</td>

<td> 12</td><td>AA / APES (3/1)</td><td> 25,10</td><td> 19,0</td><td> 6,1</td><td> 15300</td>

<td> 13</td><td>AA / APES (3/1)</td><td> 24,8</td><td> 13,0</td><td> 5,9</td><td> 10100</td>

<td> 14</td><td>AA / APES (3/1)</td><td> 29,46</td><td> 19,6</td><td> 5,9</td><td> 5910</td>

<td> 15</td><td>AA / APES (4/1)</td><td> 30,76</td><td> 18,5</td><td> 5,9</td><td> 4660</td>

<td> 16</td><td>AA / APES (4/1)</td><td> 24,9</td><td> 16,0</td><td> 6,0</td><td> 12600</td>

<td> 17</td><td>AA / APES (4/1)</td><td> 25,16</td><td> 15,0</td><td> 4,1</td><td> 43700</td>

<td> 18</td><td>AA / APES (6/1)</td><td> 24,10</td><td> 20,0</td><td> 6,0</td><td> 14200</td>

<td> 19</td><td>AA / APES (6/1)</td><td> 27,15</td><td> 42,4</td><td> 4,1</td><td> 138090</td>

<td> 20</td><td>AA / APES (6/1)</td><td> 30,13</td><td> 15,2</td><td> 4,1</td><td> 5250</td>

AA - acrylic acid

MAA = methacrylic acid

APES = allyl polyethoxylated (10) ammonium sulfate containing 10 moles of ethylene oxide, DVP-010, ex Bimax Inc.

AHPS = 1-allyloxy-2-hydroxypropyl-3-sulfonic ether, from BetzDearborn Inc.

AAE-10 phosphate = poly (oxy) ethylene glycol allyl ether phosphate (10 moles of ethylene oxide)

AMPS® = 2-acrylamido-2-methylpropanesulfonic acid, ex Lubrizol Inc.

Example 9

Inhibition of phosphate scale formation. Test protocol with cylinder

The phosphate scale formation inhibition test was carried out according to the static beaker test with varying contents of the polymer used. The protocol for this test requires the addition of the treatment polymer to 100 ml of a solution containing calcium and phosphate ions and a pH of 8.2 at 70 ° C. After 18 hours, some of the solution was filtered hot and the pH was adjusted to &lt;2.0 with hydrochloric acid. The percent inhibition was calculated by determining the phosphate concentration in the treated, starting and control solutions. The appearance of the solution was visually inspected and compared to the stock solutions. The test conditions were 400 ppm Ca, 100 ppm Mg and M alkalinity of 35 ppm, all values ​​expressed as CaCO3.

PL 204 918 B1

Table 2 summarizes the percent inhibition of the known polymeric inhibitor / dispersant system and polymers over a wide dose range. Table 3 summarizes the percent inhibition of the known polymeric inhibitor / dispersant system and polymers over a wide dose range in the presence of 3ppm FeCl2. The data in Tables 2 and 3 show the effectiveness of the polymer treatment compared to the known treatment.

Table 2: Percentage of inhibition of various inhibitor / dispersant polymeric systems.

<td>Treatment</td><td>5 ppm</td><td>7.5 ppm</td><td>10 ppm</td><td>12 ppm</td>

<td>AA / AHPS *</td><td> 16,5</td><td> 12</td><td> 36,5</td><td> 97</td>

<td>AA / AHPS / APES (3/1/1)</td><td> 75</td><td> 90</td><td> 96,5</td><td> 97,5</td>

<td>AA / APES (3/1)</td><td> 59,7</td><td> 100</td><td> 96,5</td><td> 96,7</td>

AA / AHPS means acrylic acid / 1-allyloxy-2-hydroxypropyl-3-sulfonic ether, Mw about 15,000.

AA / AHPS / APES is acrylic acid / 1-allyloxy-2-hydroxypropyl-3-sulfonic ether / allyl polyethoxy sulfate prepared according to Example 3 above.

AA / APES is acrylic acid / allyl polyethoxy sulfate prepared according to Example 1 above.

* comparative example

Table 3: Percentage of inhibition of various inhibitor / dispersant polymeric systems in the presence of 3 ppm FeCl2.

<td>Treatment</td><td>5 ppm</td><td>7.5 ppm</td><td>10 ppm</td><td>12 ppm</td>

<td>AA / AHPS *</td><td> 0</td><td> 3,3</td><td> 77,8</td><td> 100</td>

<td>AA / AHPS / APES (3/1/1)</td><td> 25,5</td><td> 80,5</td><td> 100</td><td> 100</td>

<td>AA / APES (3/1)</td><td> 56,6</td><td> 100</td><td> 100</td><td> 100</td>

AA / AHPS means acrylic acid / 1-allyloxy-2-hydroxypropyl-3-sulfonic ether, Mw about 15,000.

AA / AHPS / APES is acrylic acid / 1-allyloxy-2-hydroxypropyl-3-sulfonic ether / allyl polyethoxy sulfate prepared according to Example 3 above.

AA / APES is acrylic acid / allyl polyethoxy sulfate prepared according to Example 1 above.

* comparative example

Example 10

Inhibition of phosphate scale formation

Dynamic heat transfer simulation

Development studies were also initiated using an AA / APES (3: 1), Mw of approximately 18,000, i.e. a chemical mechanism under laboratory scale dynamic heat transfer conditions in a cooling test rig. The tested water contained 600 ppm Ca, 300 ppm Mg, M alkalinity was 50 ppm (all values ​​expressed as CaCO3), 15 ppm orthophosphate, 3 ppm pyrophosphate, 1.2 ppm of halogen substituted azole as a corrosion inhibitor, and the polymer or AA / APES (Mw about 18,000), AA / AHPS (Mw about 15,000), or AA / AHPS / APES (Mw about 13,000). The following operating parameters were used: temperature of mixing 49 ° C (120 ° F), heat transfer rate 25,237.5 W / m²(8,000 BTU / (ft²* hour)) across mild steel heat transfer tube, water flow rate 0.85 m / s (2.8 ft / sec), 1.4 days residence time (up to 75% depletion) and test duration 7 days. Both mild steel and marine brass samples were also placed in the test rig. A summary of the polymer comparison is shown below.

<td></td><td>Dosage (ppm)</td><td>Cloudy (NTU)</td><td>Delta PO4 (ppm)</td><td>Description of heat transfer</td>

<td>AA / AHPS</td><td> 4</td><td> 0,68</td><td> 0,23</td><td>Not present - Slight deposition</td>

<td>AA / AHPS</td><td> 2</td><td> 0,36</td><td> 0,2</td><td>Flows - Very slight deposition</td>

<td>AA / APES</td><td> 2</td><td> 0,15</td><td> 0,2</td><td>Flows - No Deposition</td>

In this simulation, three parameters were monitored that indicate the performance of the polymer. These are: 1) the average turbidity values ​​in the cooling water, 2) the average phosphate values

The delta (difference between the filtered and unfiltered phosphate concentrations) and 3) the amount of deposition that is observed on the heat transfer tube. Under the conditions of such a recirculating device, 5 ppm AA / AHPS is needed as a deposit control agent to maintain an acceptable heat transfer. The lower dosage, i.e. 4 ppm AA / AHPS, fails as indicated by the slight deposition observed on the tube surface. In contrast, 2 ppm AA / APES not only maintains lower mean haze values ​​and delta phosphate values, but also maintains the heat transfer surface without deposition. This is a significant reduction (60%) of the amount of polymer needed to control deposition in this cooling water.

An additional test was performed with two interfering parameters, ie elevated temperature / heat flux and an iron contamination of 3 ppm. These results are shown below.

<td></td><td>Dosage (ppm)</td><td>Cloudy (NTU)</td><td>Delta PO4 (PPm)</td><td>Description of heat transfer</td>

<td>High temperature/ Stream AA / AHPS *</td><td> 5</td><td> 0,33</td><td> 0,2</td><td>Not present - Slight deposition</td>

<td>AA / APES</td><td> 2</td><td> 0,31</td><td> 0,5</td><td>Flows - Very slight deposition</td>

<td>3 ppm Fe + 2 A / AHPS *</td><td> 12</td><td> 7,1</td><td> 1,2</td><td>Not present - Slight deposition</td>

<td>AA / AHPS *</td><td> 9</td><td> 12,9</td><td> 3,7</td><td>Not present - Slight deposition</td>

<td>AA / APES</td><td> 6</td><td> 5,3</td><td> 0,6</td><td>Flows - No Deposition</td>

* comparative example

This high temperature / flux evaluation was performed using a mixing temperature of 60 ° C (140 ° F) and a heat flux of 50,475 W / m² (BTU / (feet²* hour)) across mild steel heat transfer tube. Again, simulation with AA / AHPS at 5ppm dosing fails and significant heat transfer deposition was observed. When assessing the 2ppm AA / APES concentration, only a very small amount of sediment was observed under these harsh conditions.

Iron contamination studies were carried out by adding 0.5 ppm iron (Fe⁺²) to cooling water after the initial 24-hour period from assessment. A continuous stream of the iron solution was then introduced into the test device by regulating to a content of 3 ppm iron, i.e. a solution of 100 ppm Fe⁺² was now fed into the measuring device at a rate of 0.24 mls / minute. Under these conditions, AA / AHPS proved ineffective with dosing at both 9ppm and 12ppm. Higher turbidity values ​​(7-13 NTU) and delta phosphate values ​​(1-3.7 ppm) were observed, as well as unacceptable deposition on the heat transfer surface. The use of AA / APES at lower doses of 6 ppm kept the mean turbidity value (5.3 NTU) lower, the delta phosphate value lower (0.6 ppm), and most importantly, it prevented deposition on the surface of the heat transfer tube.

Example 11

Inhibition of silica polymerization

A silica polymerization inhibition study was performed. The test requires the preparation of 100 ml of a 500 ppm silica solution and adjustment of the pH to 7.4, and the addition of 30 ppm of the polymer to the treatment. This solution was placed in a 30 ° C water bath and monomeric silica determinations were started and repeated every 30 minutes. A test silica, The Hach Molybdian Reactive Silica, was used to determine the polymerization of silica. As polymerization occurs, the monomeric silica levels are reduced. If the polymer treatment is effective, higher concentrations of monomeric silica are achieved relative to the untreated control. Tables 4 and 5 summarize the test results of several common treatment systems as well as the polymer. At each time interval, the AA / APES system maintains higher levels of monomeric silica, ie it inhibits polymerization relative to the other treatment.

PL 204 918 B1

Table 4: Silica contents (ppm) versus time (minutes) for each treatment

<td>Time</td><td>Attempt control</td><td>AA / AHPS Mw approx 18,000</td><td>AA / PEG Mw ~ 35,000</td><td>AA / AHPS / PEG Mw ~ 25-28,000</td><td>Dequest 2010</td><td>AA / AHPS Mw about 13,000</td>

<td> 0</td><td> 430</td><td> 460</td><td> 470</td><td> 485</td><td> 492</td><td></td>

<td> 30</td><td> 390</td><td> 380</td><td> 408</td><td> 438</td><td> 458</td><td> 463</td>

<td> 60</td><td> 368</td><td> 325</td><td> 355</td><td> 400</td><td> 472</td><td> 395</td>

<td> 90</td><td> 325</td><td> 302</td><td> 322</td><td> 358</td><td> 368</td><td> 343</td>

<td> 120</td><td> 300</td><td> 288</td><td> 312</td><td> 328</td><td> 342</td><td> 318</td>

<td> 150</td><td> 278</td><td> 278</td><td> 290</td><td> 318</td><td> 328</td><td> 298</td>

<td> 180</td><td> 275</td><td> 262</td><td> 280</td><td> 295</td><td> 308</td><td> 275</td>

<td> 210</td><td> 260</td><td> 258</td><td> 270</td><td> 282</td><td> 300</td><td> 290</td>

<td> 240</td><td> 242</td><td> 240</td><td> 242</td><td> 268</td><td> 270</td><td> 258</td>

<td> 270</td><td> 230</td><td> 245</td><td> 260</td><td> 270</td><td> 268</td><td> 253</td>

<td> 300</td><td> 235</td><td> 242</td><td> 262</td><td> 255</td><td> 268</td><td> 243</td>

<td> 330</td><td> 222</td><td> 238</td><td> 242</td><td> 248</td><td> 260</td><td> 238</td>

<td> 360</td><td> 230</td><td> 242</td><td> 242</td><td> 245</td><td> 255</td><td> 230</td>

<td> 390</td><td> 225</td><td> 215</td><td> 230</td><td> 230</td><td> 248</td><td> 225</td>

PEG stands for poly (oxy) ethylene glycol allyl ether (10 moles ethylene oxide)

Dequest 2010 stands for Etidronic Acid

All the examples in Table 4 are comparative.

Table 5: Silica contents (ppm) versus time (minutes) for each treatment.

<td>Time</td><td>Control sample *</td><td>Acumer 1100 *</td><td>AA / APES Mw approximately 18,000</td><td>Belclen 400 *</td><td>PESA *</td>

<td> 0</td><td> 430</td><td> 530</td><td> 495</td><td> 483</td><td> 495</td>

<td> 30</td><td> 390</td><td> 368</td><td> 458</td><td> 400</td><td> 463</td>

<td> 60</td><td> 368</td><td> 320</td><td> 468</td><td> 365</td><td> 445</td>

<td> 90</td><td> 325</td><td> 273</td><td> 450</td><td> 325</td><td> 420</td>

<td> 120</td><td> 300</td><td> 263</td><td> 433</td><td> 310</td><td> 385</td>

<td> 150</td><td> 278</td><td> 250</td><td> 425</td><td> 283</td><td> 363</td>

<td> 180</td><td> 275</td><td> 240</td><td> 418</td><td> 275</td><td> 348</td>

<td> 210</td><td> 260</td><td> 248</td><td> 388</td><td> 265</td><td> 325</td>

<td> 240</td><td> 242</td><td> 232</td><td> 388</td><td> 255</td><td> 302</td>

<td> 270</td><td> 230</td><td> 228</td><td> 375</td><td> 255</td><td> 282</td>

<td> 300</td><td> 235</td><td> 220</td><td> 362</td><td> 240</td><td> 280</td>

<td> 330</td><td> 222</td><td> 222</td><td> 345</td><td> 235</td><td> 270</td>

<td> 360</td><td> 230</td><td> 213</td><td> 343</td><td> 238</td><td> 265</td>

<td> 390</td><td> 225</td><td> 215</td><td> 332</td><td> 232</td><td> 252</td>

Acumer 1100 is a polyacrylic acid available from Rohm &amp; Haas. Belclen 400 is available from FMC Corp.

PESA means polyepoxysuccinic acid * comparative example

PL 204 918 B1

Example 12

Inhibition of silica deposition

Bottle tests were performed to evaluate the effect of treatment on the solubility of silica and phosphate in the presence of aluminum. The tested waters contained 700 ppm of calcium, 185 ppm of magnesium and the basicity of M was 35 ppm (all values ​​as CaCO3), 90 ppm SiO2, 14 ppm orthophosphate, 2 ppm pyrophosphate and the specific polymer to be treated. The treatment agents included an AA / AHPS copolymer (Mw of about 15,000), a second higher molecular weight AA / AHPS copolymer (Mw of about 55,000), and HEDP (hydroxyethylidene diphosphonic acid). Test waters were placed as 100 ml samples. The dose of 5.0 ppm Al³⁺ was added to each sample, the pH was adjusted to 8.0 and the samples were kept at 54 ° C (130 ° F) overnight. Then, the filtered / unfiltered (F / UF) water components were analyzed.

The following table indicates the results.

<td>Treatment agent, ppm</td><td>Al (F / UF)</td><td>Mg (F / UF)</td><td>TP (F / UF)</td><td>SiO2 (F / UF)</td><td>Ca (F / UF)</td>

<td>AA / AHPS-1, 20 *</td><td> 0,1/5,1</td><td> 190/190</td><td> 6,5/16</td><td> 71/89</td><td> 680/700</td>

<td>AA / AHPS-1, 35 *</td><td> 0,8/5,1</td><td> 180/190</td><td> 8,9/16</td><td> 71/88</td><td> 670/690</td>

<td>AA / AHPS-1, 50 *</td><td> 2,0/5,0</td><td> 180/190</td><td> 11/16</td><td> 75/88</td><td> 670/690</td>

<td></td><td></td><td></td><td></td><td></td><td></td>

<td>AA / AHPS-2, 20 *</td><td> 0,2/5,0</td><td> 190/190</td><td> 6,2/15</td><td> 71/88</td><td> 670/690</td>

<td>AA / AHPS-2, 35 *</td><td> 0,8/5,1</td><td> 190/190</td><td> 8,5/16</td><td> 73/89</td><td> 690/700</td>

<td>AA / AHPS-2, 50 *</td><td> 2,8/5,1</td><td> 190/190</td><td> 15/15</td><td> 79/88</td><td> 680/700</td>

<td></td><td></td><td></td><td></td><td></td><td></td>

<td>AA / AHPS-2, 20 + HEDP, 1.7 *</td><td> 0,2/5,1</td><td> 190/190</td><td> 6,1/17</td><td> 71/90</td><td> 680/710</td>

<td>AA / AHPS-2, 35 + HEDP, 3.0 *</td><td> 0,7/5,1</td><td> 190/190</td><td> 9,6/19</td><td> 73/89</td><td> 690/700</td>

<td>AA / AHPS-2, 50 + HEDP, 4.3 *</td><td> 1,0/4,9</td><td> 190/180</td><td> 12/19</td><td> 73/86</td><td> 680/680</td>

<td></td><td></td><td></td><td></td><td></td><td></td>

<td>AA / APES, 20</td><td> 4,0/5,1</td><td> 190/190</td><td> 13/15</td><td> 83/88</td><td> 690/690</td>

<td>AA / APES, 35</td><td> 4,8/5,1</td><td> 190/190</td><td> 15/15</td><td> 87/90</td><td> 700/710</td>

<td>AA / APES, 50</td><td> 5,0/5,0</td><td> 190/180</td><td> 15/14</td><td> 88/87</td><td> 700/680</td>

* comparative example

As shown by the Table data, AA / AHPS 1 (Mw of about 15,000), AA / AHPS-2 (Mw of about 55,000), and AA / AHPS-2 + HEDP were ineffective at maintaining solubility, even at very high doses. In contrast, the AA / APES polymer (Mw of about 13,000) provided the solubility of all substances, even when administered at lower dosages.