MXPA00007307A - Entirely organic multifunctional composition specific for water treatment with high content of total hardness in reserve water of cooling towers - Google Patents

Abstract

The present invention refers to a completely water soluble composition presenting an elevated efficiency for the chemical treatment of water of cooling towers with high content of total hardness, chiefly composed of calcium, in reserve waters of cooling towers in petrochemical complexes, allowing to work at high concentration cycles and maintain an adequate control of corrosion, incrustation and dispersion in the heat interchange equipment, avoiding the tendency of soiling of the process equipments, as well as the bacterium growth control. This composition also eliminates heavy metals when applying formulations in the cooling systems with heavy metals such as zinc. With the application of this invention it is avoided the effluents pollution, because it is a multifunctional product whose chemical composition is completely organic and biodegradable.

Description

ALL ORGANIC MULTIFUNCTIONAL COMPOSITION, SPECIFIC FOR THE TREATMENT OF WATER WITH HIGH CONTENT OF TOTAL HARDNESS IN THE REPLACEMENT WATER IN COOLING TOWERS.

DESCRIPTION TECHNICAL FIELD OF THE INVENTION The present invention relates to a composition completely soluble in water that has a high efficiency for the chemical treatment of water cooling towers with high content of total hardness, mainly calcic, in the spare water in cooling towers of the Petrochemical Complex of the North Zone of the state of Veracruz, which allows to work at high concentration cycles and maintain an adequate control of corrosion, scale and dispersion in the heat exchange equipment, also avoiding the tendency to fouling the process equipment, as well as the control of bacterial growth. It also favors the elimination of heavy metals by applying formulations in cooling systems containing heavy metals such as zinc. Avoiding with the application of this invention the contamination of the effluents, since it is a multifunctional product whose chemical composition is totally organic and biodegradable.

BACKGROUND OF THE INVENTION The water supplied as a replacement to the cooling towers contains cations, such as calcium, magnesium, iron, sodium, potassium and copper, and various anions such as bicarbonates, carbonates, sulphates, phosphates and soluble silica, interacting with each other when the system temperature and water concentration cycles, exceeding the solubility product of its components each of its reaction products are precipitated. The solubility of the components present varying for the following reasons: the concentration of salts, changes in pH, and temperature; as well as by the introduction of additional ions that form insoluble compounds with the ions already present in the solution.

These reaction products precipitate on the surfaces of the cooling system, forming deposits, whose accumulation prevents effective heat transfer, interfering with the flow of water, facilitates corrosive processes and bacterial growth. Representing a serious problem in the systems of the cooling towers, since the costs for maintenance, cleaning and removal of deposits are increased.

Likewise, corrosion in heat exchange equipment and interconnection lines significantly reduces the useful life of the aforementioned equipment.

For the control of corrosion, incrustation and dispersion of inorganic materials, as well as microbiological control, the following products have been previously used: CORROSION CONTROL For the control of this phenomenon caused by the presence of dissolved oxygen in the recirculating water, as well as by the presence of other pollutants coming from the main process such as: hydrogen sulfide, hydrocarbons, ammonia, etc., various compounds have been used to Based on chromates and zinc, which showed a satisfactory behavior in this application, however the frequent use of these products have caused pollution problems in the receiving bodies such as: rivers, dams and lagoons, so it has been recommended the elimination of the chromium compounds and restricted the consumption of zinc-based compounds, in this case limiting the concentration to values lower than 20 ppm in the effluents of refineries and petrochemical complexes in the country.

CONTROL OF INCRUSTATION.

To avoid the formation of deposits of encrusting salts of low solubility, chelate-type compounds such as ethylene diamine tetraacetic acid, nitrile triacetic acid and its salts favoring the solubilization of calcium and magnesium compounds have been used; also to reduce the tendency to crystallization and deposit formation of these compounds, various compounds have also been used, such as amino-trimethylene phosphoric acid, hydroxyethylidene diphosphonic acid and low and medium molecular weight polymers based on acrylic acid and acrylamide. .

CONTROL OF ENSUCIAMIENTO.

The presence of organic matter dissolved salts, and various pollutants in the water used as a replacement for the cooling systems, causing the gradual formation of hard and adherent bacteriological deposits mainly on the metallic surfaces of heat exchange equipment, thereby reducing the efficiency of these and causing severe damage of obstruction, corrosion and fouling.

To keep under control the formation of deposits of organic and inorganic materials such as: clays, mud and silt, natural polymeric materials, such as tannins and lignin derivatives (lignosulfonates) have been used mainly; however, these mentioned compounds have as their main drawback their high susceptibility to chemical or biological degradation, which further reduces their efficiency. Currently, non-ionic biodispersants are used that keep organic matter in suspension and reinforce the action of oxidizing and non-oxidizing biocides.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multifunctional composition of "all organic" chemicals for the treatment of cooling water with a high content of total hardness, mainly calcic, in the spare water in cooling towers of the Petrochemical Complex of the North Zone of the Veracruz state. By applying this invention, it is possible to keep under control the problems of corrosion, fouling, dispersion, sludge formation and allows us to obtain high efficiency and extensive technical, economic and ecological advantages.

The composition object of the present invention presents a highly satisfactory behavior for the control of problems of corrosion, fouling and fouling that generally occur in cooling systems with high content of total hardness, mainly calcic, in the spare water of the petrochemical complexes .

The product IMP-TE-510.1 contains in its formulation an inhibitor of incrustation with high efficiency, organic phosfonocarboxílico type. With the continuous use of this product at dosages in the range of 20 to 75 ppm it is possible to keep the cooling systems free of scale, having a high efficiency in heat exchange equipment, managing to lengthen the operating periods of the process plants, as well as having significant energy savings. The multifunctional composition object of this invention has the advantage of complying with the current environmental legislation established by the Ministry of the Environment, without the above resulting in a lower efficiency in terms of protection against corrosion and fouling in the systems Cooling.

The composition IMP-TE-510.2 is an excellent corrosion inhibitor composed of an organic inhibitor of the phosphonate type that controls the corrosion rates on metallic surfaces of cooling systems mainly composed of white metals such as carbon steel, the formulation object of this invention allows us to have under control the corrosion within the specified ranges 5 pma maximum, so it is a specific corrosion inhibitor for spare waters with high content of total hardness, mainly calcic, as is the case of the spare water of the complex petrochemical of the northern zone of the State of Veracruz; obtaining efficiencies of inhibition to the incrustation of calcium as calcium carbonate above 90% in tests at laboratory level.

The objectives of the present invention are: 1. To provide a completely water soluble multifunctional chemical composition that satisfactorily inhibits fouling, corrosion and fouling in cooling water systems with high total hardness content, mainly calcic, in the replacement water in cooling towers.

Allows savings in the consumption of spare water to the cooling towers, up to 57% achieved a greater number of concentration cycles without presenting incrustation, corrosion and fouling problems.

In waters containing high hardness and low concentration of silica, it manages to effectively disperse these materials preventing their precipitation and thus preventing them from depositing on metal surfaces, decreasing fouling in cooling systems by up to 30%, which allows avoid unforeseen plant shutdowns, continuing with production programs and having significant savings for maintenance and cleaning in heat exchange equipment.

The multifunctional composition of the present invention is presented in a liquid state, divided into two parts, in order to make its application more efficient, achieving chemical treatments with greater technical and economic advantages for the spare water of the petrochemical center in the north of the country. , this invention has the following characteristics and compositions: IMP-TE-510.1 COMPONENT% WEIGHT Copolymer KT-2800 10-60 Acid 2 phosphonobutane, 1, 2,4 tricarboxylic 2-40 1-hydroxyethylidene 1,1-diphosphonic acid 5-50 IMP-TE-510.2 COMPONENT% WEIGHT Demineralized water 10-80 Hydroxyphosphate acetic acid 5-40 Monoethanolamine 2-30 IMP-TE-510.1 contains in its formulation from 10 to 60% by weight of the organic copolymer KT-2800, from 2 to 40% by weight of 2-phosphonobutane, 1, 2,4-tricarboxylic acid and from 5 to 50% by weight of 1-hydroxyethylidene 1,1-diphosphonic acid.

In its formulation, IMP-TE-510.2 contains from 5 to 40% by weight of hydroxyphosphonic acid, from 2 to 30% by weight of monoethanolamine and from 10 to 80% by weight of demineralized water.

The hydroxyphosphonic acetic acid compound present in the formulation promotes the formation of a protective film on metal surfaces, which constitutes a mechanical and electrochemical barrier that passivates the metal against corrosive attack. This film has a high degree of thermal stability and oxidation, so it is not easily removed.

The hydroxyphosphonic acetic acid active component of the present invention has the following formula: OH The organic copolymer KT-2800 of low molecular weight present in the composition object of the invention, works by dispersing the particles that are in solution, inhibiting the precipitation of calcium carbonate salts and silica as such specifically. The phosphonated active component present in this invention has the following structural chemical formulation.

OR O CH2 - C - OH HO P-O-C C-OH HO CH2 O CH2-C-OH & The usefulness of this compound is that it is a stabilizing and scale inhibiting agent for aqueous solutions supersaturated, especially with calcium carbonate, but also with calcium sulfate and other salts or hydroxides that are difficult to dissolve.

The mechanism of action of this inhibitor supposes an adsorption of the same in the points of growth of the crystals, giving rise to a deformation of the same and avoiding an ordered crystallization. Another of the phosphonated compounds present in the invention has the following chemical formula: HO OH OH I I I HO - P C - P - OH II I II CH3 O This compound has properties as a sequestrant, manifesting itself in an ability to form metal ion complexes at stoichiometric concentrations, it also has properties as a dispersant of solid materials and inhibition of precipitation, as well as a high thermal stability due to its resistance to decomposition in aqueous solutions. in conditions of high temperature and extreme pH conditions.

EXAMPLES IMP-TE-510.1 EXAMPLE No. 1 400.0 g of demineralized water and 350.0 g of hydroxyphosphate acetic acid were placed in a 1 liter glass flask, this mixture had a pH of about 1.0.

Then 250 g of monoethanolamine were added, a temperature increase was observed no higher than approximately 50 ° C, therefore a cooling system was required without suspending the agitation, it was important to maintain the agitation and cooling until it was reached a temperature lower than 30 ° C and a pH greater than 1.

During the procedure it was necessary to make sure to maintain the agitation in the container, as well as to prevent the temperature of the contents of the container from exceeding 60 ° C. In addition, the addition of a new reagent was done when the contents of the container were at a lower temperature than 40 ° C.

A product with the following characteristics was obtained: Appearance Dark brown liquid (amber) Specific gravity, at 20/4 ° C 1.0 - 1.5 Drain temperature, ° C -35 - -45 pH of the solution at 1% by weight < 1.8 EXAMPLE 2 600.0 g of demineralized water and 200.0 g of hydroxyphosphonic acid were placed in a 1 liter glass vessel with a mechanical stirring jacket, this mixture had a pH of about 1.5.

Then, 200 g of monoethanolamine were added, a temperature increase was observed no higher than approximately 50 ° C, therefore a cooling system was required without suspending the stirring, it was important to maintain the agitation and cooling until it was reached a temperature lower than 30 ° C and a pH greater than 1.

During the procedure it was necessary to make sure to maintain the agitation in the container, as well as to prevent the temperature of the contents of the container from exceeding 60 ° C. In addition, the addition of a new reagent was done when the contents of the container were at a temperature below 40 ° C. A product with the following characteristics was obtained: Appearance Dark brown liquid (amber) Specific gravity, at 20/4 ° C 1.0 - 1.5 Drain temperature, ° C -35 - -45 pH of the solution at 1% by weight < 1.8 IMP-TE-510.2 EXAMPLE 3 Into a 1 liter glass vessel provided with a cooling jacket and mechanical stirring, 150 g of 2-phosphonobutane, 1,2,4-tricarboxylic acid were placed. Then 250 g of 1-hydroxyethylidene-1,1-diphosphonic acid were added without variation in temperature and pH. Finally, 600.0 g of the KT-2800 copolymer were added without variation in temperature and a pH of approximately 2.15.

No increase in temperature was observed, therefore a cooling system was not required; however, it was important to maintain agitation for the addition of a new reagent.

A product with the following characteristics was obtained: Appearance Transparent yellow liquid Specific gravity, at 20/4 ° C 1.0 - 1.7 Brookfield viscosity, cPs at 20 ° C 6.0 - - 30.0 Saybolt color +30 - +40 pH of the 1% by weight solution 3 - 5 EXAMPLE 4 In a 1-liter glass vessel provided with cooling jacket and mechanical stirring, 300 g of 2-phosphonobutane, 1, 2,4-tricarboxylic acid were placed. Next, 300 g of 1-hydroxyethylidene-1,1-diphosphonic acid were added without variation in temperature and pH. Finally, 400 g of the KT-2800 copolymer was added without variation in temperature and a pH of approximately 3.58.

No increase in temperature was observed, therefore a cooling system was not required; however, it was important to maintain agitation for the addition of a new reagent.

A product with the following characteristics was obtained: Appearance Transparent yellow liquid Specific gravity, at 20/4 C 1.0 - 1.7 Brookfield viscosity, cPs at 20 ° C 6.0 - 30.0 Saybolt color +30 - +40 pH of the 1% by weight solution 3 - 5 EXAMPLE 5 In this example, the results of the laboratory-level evaluation of the formulations reported in examples 1 to 4 are shown 1. - INHIBITION TO THE PRECIPITATION OF CaCO3 Method IMP-PE-ll-1 In this procedure 500 ml of spare water is measured according to the petrochemical complex to be studied in this case, that of the northern part of the state of Veracruz, the selected dosage of inhibitor is added, they are agitated and maintained in heating at 65 to 70 ° C by controlling the pH to the selected optimum in this particular case 8.1 until reaching the volume corresponding to 3 or 5 cycles of concentration as appropriate.

Calcium is determined by titration with EDTA.

RESULTS Efficiency at inhibition% Dosage ppm 40 60 80 Example 1 14 19 27 Example 2 16 18 21 Example 3 88 94 98 Example 4 79 85 91 2. - INHIBITION TO THE PRECIPITATION OF CaSO4 Method NACE-ST-TM-03-74 In this procedure, equal volumes of test solutions a and b are mixed in bottles, the selected dosage of the inhibitor is added, stirred and kept under heating at 71 ° C / 72 hrs.

Calcium is determined by titration with EDTA.

Composition of the brines: a) 11.1 g / l of CaCl22H20 7.5 g / l NaCl b) 7.5 g / l NaCI 10.66 g / l NaS04 RESULTS Efficiency at inhibition% Dosage ppm 40 60 80 Example 1 11 13 13 Example 2 10 10 10 Example 3 94 96 97 Example 4 89 91 94 3. - DISPERSION OF CAOLÍN.

ROHM AND HAAS method. In this procedure a test dispersion is prepared, with the following components: 430 ml of a solution containing 200 ppm CaCOβ (CaCl2 as CaCO3) and 0.43 g of kaolin (1000 ppm kaolin).

In this procedure, a test dispersion is prepared by mixing 430 ml of a CaCl2 solution equivalent to 200 ppm as CaCO3 0.43 g of kaolin (equivalent to 100 ppm of kaolin) and the dispersing product to be evaluated (0.5% weight). Subsequently the pH is adjusted to 7.5 in soda solution, the mixture is stirred in a blender for 10 minutes and the Brookfield viscosity is determined at 20 ° C.

RESULTS Viscosity cPs Example 1 95 Example 2 90 Example 3 16 Example 4 28 It is noted that Example 3 has a lower viscosity because the clay is better dispersed. 4. - DISPERSION OF IRON OXIDE.

ROHM AND HAAS method.

A solution is prepared that contains: 200 ppm of CaCl2 as CaCO3 (430 ml) 0.30 of Fe03 (700 mg / l Fe203) The pH of the test solution is adjusted to 7.5 with soda solution, 60 ppm of the additive to be evaluated is added and the mixture is stirred for 15 minutes.

RESULTS TURBIDEZ, NTU Example 1 41 Example 2 38 Example 3 97 Example 4 91 It is noted that Example 3 presents a higher turbidity due to the higher iron content it has in suspension.

. - INHIBITION TO CORROSION.

Corrosion Method 83 paper No 281 In this procedure a corrosive solution with the following composition is used.

RESULTS mg / l CaCl2.2H2O 442 MgSO4 120 Na2SO4 360 NaHCO3 61 Equivalent to: 17 400 ppm of hardness as CaC03 10 ppm of alkalinity as CaC03 The pH is adjusted with soda to 6.5 The carbon steel and admiralty test cores are immersed in the test solution for 20 hrs at room temperature, with constant aeration. The efficiency is determined by the inhibition by weight difference.

RESULTS Efficiency to corrosion in% Dosage ppm 60 80 Example 1 95 98 Example 2 91 93 Example 3 09 15 Example 4 10 18 As can be seen, the formulation reported in Example 1 shows better performance in the corrosion inhibition tests, and the formulation reported in Example 3 shows better behavior in the inhibition tests to the incrustation, kaolin dispersion and oxide dispersion. iron.

Claims (6)

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and therefore the contents of the following clauses are claimed from our property:

1. An all-organic multifunctional composition, specific for the treatment of water with a high content of total hardness in the replacement water in cooling towers, characterized in that it is divided into two parts: the first contains in its formulation from 5 to 40% by weight of hydroxyphosphate acetic acid, from 2 to 30% by weight of monoethanolamine and from 10 to 80% by weight of demineralized water (IMP-TE-510.1). The second formulation contains from 10 to 60% by weight of the organic copolymer KT-2800, from 2 to 40% by weight of 2-phosphonobutane-1, 2,4-tricarboxylic acid and from 5 to 50% by weight of 1-hydroxyethylidene-1-acid. , diphosphonic (I MP-TE-510.2).

2. A multifunctional all organic composition, specific for the treatment of water with high total hardness content in the cooling water in cooling towers according to clause 1, characterized because it inhibits corrosion, fouling, fouling and microbiological growth in water systems Cooling.

3. An all-organic multifunctional composition, specific for the treatment of water with high total hardness content in the replacement water in cooling towers in accordance with clauses 1 and 2, characterized in that it does not contain heavy metals and therefore does not contribute to increase the concentration of them in the effluents of refineries and plants «Petrochemicals. 5

4. A multifunctional all organic composition, specific for the treatment of water with high total hardness content in the replacement water in cooling towers in accordance with clauses 1 to 3, characterized because it allows to increase up to 12 times the concentration of solids in cooling water, thus, there is a significant saving in the spare water requirements in these equipments and consequently a decrease in the electric power consumption of the replacement water dosing equipment.

5. An all-organic multifunctional composition, specific for the treatment of water with a high content of total hardness in the replacement water in cooling towers in accordance with clauses 1 to 4, characterized in that it presents high efficiency of inhibition to the incrustation still in systems 20 cooling whose recirculation waters contain high concentrations of calcium, magnesium and silica salts.

6. A multifunctional all organic composition, specific for the treatment of water with high total hardness content in the replacement water in cooling towers in accordance with clauses 1 to 5, characterized because it presents a high efficiency of dispersion of solids in cooling systems with high content of total hardness, mainly calcica, which allows to reduce the fouling in the tubes of the heat exchange exchangers. A multifunctional all organic composition, specific for the treatment of water with high total hardness content in the replacement water in cooling towers in accordance with clauses 1 to 6, characterized because it allows to keep under control the microbial growth in water systems cooling with high content of total hardness, mainly calcic, which in turn allows significantly reduce corrosion and fouling, which occurs below the deposits of organic material in heat exchangers. A multifunctional "all organic" composition specifically for the treatment of water with a high content of total hardness in the replacement water in cooling towers in accordance with clauses 1 to 7, characterized in that it keeps under control the corrosion in copper pipes and their alloys, as well as other carbon steel components of heat exchangers in cooling systems.