MXPA00007308A - Semiorganic multifunctional composition for water treatment with low content of calcium and high estability rate in cooling towers - Google Patents

Abstract

The present invention refers to water soluble composition named IMP-TE-511, presenting an elevated efficiency for the chemical treatment of water of cooling waters with low calcium content and high stability rate, in reserve waters of petrochemical complexes, with high concentration cycles and an adequate control of corrosion, incrustation and dispersion in the process equipments, particularly in ethylene, polypropylene, chlorates 1 y II, acetaldehyde, oxygen, acrylonitrile plants, and auxiliary services. This package includes in its formulation a corrosion inhibitor based on heavy metals.

Description

MULTIFUNCTIONAL SEMI-REGIONAL COMPOSITION FOR THE TREATMENT OF WATER WITH LOW CALCIUM CONTENT AND HIGH STABILITY INDEX IN COOLING TOWERS.

DESCRIPTION TECHNICAL FIELD OF THE INVENTION The present invention relates to a water-soluble composition called IMP-TE-511, which has a high efficiency for the chemical treatment of water from cooling towers with low calcium content and high stability index, in the spare water of the petrochemical complexes of the Pajaritos and Morelos Petrochemical Complexes, in the state of Veracruz. Zones, which allow working at high concentration cycles and maintain adequate control of corrosion, scale and dispersion in process equipment, particularly in ethylene, polypropylene, chlorinated I and II, acetaldehyde, oxygen, acrylonitrile, and auxiliary services plants . This package includes in its formulation a corrosion inhibitor based on heavy metals.

BACKGROUND OF THE INVENTION The water used in the cooling towers contains cations, such as calcium, magnesium, sodium, potassium, etc. and various anions such as bicarbonates, carbonates, sulphates, phosphates, silicates, etc. When these anions and cations are combined in concentrations where the solubility of their reaction products is exceeded, they precipitate. The solubility of the present components varies for the following reasons: 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 incrustations of calcium and magnesium salts mainly, whose accumulation prevents the transfer of thermal heat, resulting in a decrease in water flow, causing corrosive processes and bacterial growth . Representing a serious problem in the systems of the cooling towers, since the stoppages for cleaning and removal of deposits are increased.

In addition, corrosion in heat exchange equipment and interconnection lines increases operating costs due to stoppages and maintenance, which significantly reduces the useful life of the aforementioned equipment.

For the control of the aforementioned problems, corrosion inhibitors based on phosphonic zinc have been used, and for the control of the scale, phosphates, lignins, and low molecular weight homopolymers. There is no history of a mixture of corrosion inhibitors of this type.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mixture of stabilized, semi-organic zinc phosphonate for the treatment of cooling water with low calcium content and high stability index, of spare water of petrochemical complexes, allowing with the application of this package, keep under control the problems of corrosion, fouling, dispersion and sludge formation.

The composition object of this invention presents a highly satisfactory behavior for the control of corrosion, fouling and fouling problems that generally occur in the heat exchange equipment in the process plants to which the cooling towers service when using water from spare with low calcium content and a high stability index.

The product IMP-TE-511.1 contains in its formulation two corrosion inhibitors: an organic one of the phosphonocarboxylic type and another inorganic one based on heavy metals, which gives it excellent corrosion inhibition properties through a synergistic effect between both products. With the continuous use of these products at dosages in the range of 30 to 50 ppm it is possible to keep under control the corrosion rates for the parts consisting of carbon steel at a maximum of 5 MPa. The product has the advantage of complying with the specifications established by the Secretary of the Environment, without the above resulting in a lower efficiency in terms of protection against corrosion.

The product IMP-TE-511.2 is an excellent inhibitor against the incrustation, on the metallic surfaces of the cooling systems, the formulation object of the present invention contains a mixture of a derivative of phosphonic type, reinforcing this effect with a mixture of polymers of low molecular weight specific for spare waters with high stability index, and low content of calcium and alkalinity, such as the characteristics of the spare water of the Pajaritos and Morelos, Ver. petrochemical complexes, obtaining efficiencies of inhibition to the calcium incrustation as calcium carbonate above 90% in laboratory and pilot plant tests.

The objectives of the present invention are: 1. Provide a water soluble composition that satisfactorily inhibits fouling, corrosion, fouling in cooling water systems with low calcium content and high stability index in the spare water of petrochemical complexes. 2. Allows savings in the consumption of spare water, up to 65%, also decreasing the generation of wastewater by reducing the purges in the cooling towers, allowing operation at high concentration cycles without presenting incrustation, corrosion and fouling problems. because it contains in its formulation a mixture of a copolymer and an easily traceable terpolymer. 3. For waters that contain low hardness and high stability index, it allows to effectively disperse these materials preventing their precipitation resulting in high efficiency in heat exchange equipment. 4. It is considered that the technology that is provided as a remarkable advance in the field of water treatment, due to the characteristics in the composition of this product, which is due to the incorporation of zinc chloride as corrosion inhibitor specific for white metals which has a synergistic effect with the organic corrosion inhibitor of the phosphonate type.

The composition of the present invention is presented in the liquid state, divided into two parts with the following characteristics: IMP-TE-511.1 COMPONENT% WEIGHT Demineralized water 10-80 1-Hydroxyethylidene 1,1-diphosphonic acid 5-40 Zinc Chloride 5-50 Acid 2 phosphonobutane, 1,2,4 tricarboxylic 2-20 36% hydrochloric acid 5-30 IMP- -TE- -511.2 COMPONENT% WEIGHT Demineralized water 10-80 Copolymer KT-2800 5-50 Terpolymer KT-7800 5-50 2-phosphonobutane, 1, 2,4-tricarboxylic acid 2-20 Monoethanolamine 1-15 50% Potassium Hydroxide 10-50 Hydroxy Phosphonoacetic Acid 2-50 IMP-TE-511.1 contains in its formulation from 5 to 40% by weight of 1-Hydroxyethylidene 1,1-diphosphonic acid, from 5 to 50% by weight of zinc chloride, from 2 to 20 % by weight of 2-phosphonobutane, 1, 2,4-tricarboxylic acid, 5 to 30% by weight of hydrochloric acid and 10 to 80% by weight of demineralized water.

The IMP-TE-511.2 contains in its formulation from 2 to 20% by weight of 2-phosphonobutane, 1, 2,4-tricarboxylic acid, from 5 to 50% by weight of the organic copolymer KT-7800, from 5 to 50% by weight of the organic copolymer KT-2800, from 1 to 15% by weight of monoethanolamine, from 2 to 50% by weight of hydroxyphosphonoacetic acid, from 10 to 50% by weight of potassium hydroxide and from 10 to 80% weight of demineralized water.

The compound hydroxyphosphonoacetic acid and zinc chloride present in the formulations contribute to 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 to oxidation and is not easily removed.

The hydroxy-phosphonoacetic acid active component of the present invention consists of the following formula: OH The organic copolymer KT-2800 and the organic terpolymer KT-7800, both of low molecular weight, present in the composition object of the invention work by dispersing the particles that are in solution, inhibiting the precipitation of salts of calcium carbonate and silica as such specifically.

The phosphonated active component present in this invention has the following structural chemical formulation.

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 origin to a deformation of the same one and avoiding an ordered crystallization. Another of the phosphonated compounds present in the invention has the following chemical formula.

HO OH OH HO - P - C P OH II I I I O 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-511.1 EXAMPLE 1 300.0 g of demineralized water and 150.0 g of 1-hydroxyethylidene 1,1-diphosphonic acid were placed in a 1 liter glass vessel with a mechanical stirring jacket, this mixture had a pH of about 1.35.

Then, 100 g of 2-phosphonobutane, 1, 2,4-tricarboxylic acid were added without variation in temperature and pH. Subsequently, 200 g of hydrochloric acid was added slowly to 36%, showing gas evolution and an increase in temperature. Then, 250.0 g of zinc chloride were added slowly, an increase in temperature not higher than approximately 50 ° C was observed, therefore a cooling system was required without suspending the stirring, it was important to maintain the stirring and cooling until that a temperature lower than 30 ° C and a pH lower than 1 was reached.

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 80 ° C. In addition, the addition of a new reagent was done when the contents of the container were at a temperature below 50 ° C.

A product with the following characteristics was obtained: Appearance Transparent clear liquid Specific gravity, at 20/4 ° C 1.0 - 1.45 Brookfield Viscosity, cPs at 20 ° C -35 - -45 APHA Color 3 - 5 pH of the 1% by weight solution < 1.5 EXAMPLE 2 Into a 1 liter glass vessel provided with cooling jacket and mechanical stirring, 400.0 g were placed. of demineralized water and 50.0 g. of 1-Hydroxyethylidene 1,1-diphosphonic acid, this mixture had a pH of about 1.91.

Then, 100 g of 2-phosphonobutane, 1, 2,4-tricarboxylic acid were added without variation in temperature and pH.

Subsequently, 100 g was added slowly. of hydrochloric acid at 36%, observing gas evolution and an increase in temperature. Then 350.0 g of zinc chloride were slowly 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 stirring and cooling until that a temperature lower than 30 ° C and a pH lower than 1 was reached.

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 80 ° C. In addition, the addition of a new reagent was done when the contents of the container were at a lower temperature than 50 ° C. A product with the following characteristics was obtained: Appearance Clear clear liquid Specific gravity, at 20/4 ° C 1.0 - 1.45 Drain temperature, ° C -35 - -45 Zinc content 3 - 5 pH of the 1% by weight solution < 1.5 IMP-TE-511.2 EXAMPLE 3 In a 1 liter glass vessel provided with cooling jacket and mechanical stirring, 125.0 g of demineralized water and 220.0 g of the KT-2800 copolymer were placed without temperature variation and a pH of about 5.

Then 100 g of the KT-7800 terpolymer were added without temperature variation and a pH of about 4.51.

Subsequently, 100 g was added. of 2-phosphonobutane, 1,2,4-tricarboxylic acid without variation in temperature and pH. Then 155g of monoethanolamine was added slowly, observing gas evolution and a small increase in temperature. Then 200.0 g were slowly added. of 50% potassium hydroxide, an increase in temperature was observed reaching up to 70 ° C, therefore a cooling system was required without suspending the agitation and as a consequence the pH of the solution was increased up to 13.0, it was important to keep stirring and cooling until a temperature lower than 30 ° C was reached, at that time 200 g of hydroxy phosphonoacetic acid was added.

During the procedure it was necessary to ensure that the agitation was maintained in the container, as well as to prevent the temperature of the contents of the container from exceeding 70 ° C. In addition, the addition of a new reagent was done when the contents of the container were at a temperature below 30 ° C.

A product with the following characteristics was obtained: Appearance Dark brown liquid (amber). Specific gravity, at 20/4 ° C 1.1 - 1.4 Brookfield viscosity, cPs at 20 ° C 6.0 - 30.0 Saybolt color +30 - +40 pH of the 1% by weight solution > 12.5 EXAMPLE 4 In a 1 liter glass vessel provided with cooling jacket and mechanical stirring, 200.0 g of demineralised water and 250.0 g of the KT-2800 copolymer were placed without temperature variation and a pH of about 4.86. Then 125 g of the KT-7800 terpolymer were added without temperature variation and a pH of about 3.78.

Subsequently, 75 g of 2-phosphonobutane, 1,2,4-tricarboxylic acid were added without variation in temperature and pH. Then 100 g of monoethanolamine was added slowly, observing gas evolution and a small increase in temperature. Then, 100.0 g of 50% potassium hydroxide were slowly added, an increase in temperature was observed until approximately 70 ° C, therefore a cooling system was required without suspending the agitation and as a consequence the pH of the solution up to 12.5, it was important to keep stirring and cooling until a temperature lower than 30 ° C was reached, at that time 150 g of hydroxy phosphonoacetic acid was added. During the procedure it was necessary to ensure that the agitation was maintained in the container, as well as to prevent the temperature of the contents of the container from exceeding 70 ° C. In addition, the addition of a new reagent was done when the contents of the container were at a temperature below 30 ° C. A product with the following characteristics was obtained: Appearance Dark brown liquid (amber). Specific gravity, at 20/4 ° C 1.1 - 1.4 Brookfield viscosity, cPs at 20 ° C 6.0 - 30.0 APHA color +30 - +40 pH of the 1% by weight solution > 12.5 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 replacement water is measured according to the Refinery to be studied, the selected dosage of inhibitor is added, stirred and maintained in heating between 65 - 70 ° C, controlling the pH to the optimum selected in this particular case 8.1 until reaching the volume corresponding to 3 or 5 cycles of concentration according to correspond Calcium is determined by titration with EDTA.

RESULTS Efficiency at inhibition% Dosage ppm 40 60 80 Example 1 64 69 78 Example 2 58 64 72 Example 3 78 92 97 Example 4 75 88 92 2.- INHIBITION TO PRECIPITATION OF CaS04 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 71 79 83 Example 2 62 70 77 Example 3 91 94 94 Example 4 88 92 94 3.- DISPERSION OF CAOLIN.

ROHM AND HAAS method. In this procedure a test dispersion is prepared, with the following components: 430 ml of a solution containing 200 ppm CaCO3 (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 92 Example 2 77 Example 3 15 Example 4 It is observed that Example No. 3 has a lower viscosity because the clay is better dispersed. 4. - DISPERSION OF IRON OXIDE.

ROHM AND HAAS method. A solution is prepared containing: 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 45 Example 2 51 Example 3 95 Example 4 90 It is observed that the example No. 3, presents a higher turbidity due to the higher content of iron that it has in suspension.

. - INHIBITION TO CORROSION.

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

RESULTS mg / l CaCl2.2H20 442 MgS04 120 Na2S04 360 NaHC03 61 Equivalent to: 17 400 ppm hardness as CaC03 10 ppm alkalinity as CaC03 pH is adjusted with soda to 6.5 The carbon steel and admiralty test witnesses are immersed in the test solution for 20 hrs. at room temperature, with constant aeration. The efficiency to the inhibition by weight difference is determined.

RESULTS Efficiency to corrosion in% Dosage ppm 60 80 Example 1 94 98 Example 2 88 93 Example 3 11 17 Example 4 11 17 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 (5)

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. .- A semiorganic multifunctional chemical composition for the treatment of water with low calcium content and high stability index in cooling towers, consisting of two parts: the first contains 5 to 40% by weight of 1-hydroxyethylidene 1, 1 , diphosphonic; from 5 to 50% by weight of zinc chloride; from 2 to 20% by weight of 2-phosphonobutane-1,2,4-tricarboxylic acid; from 5 to 30% by weight of hydrochloric acid and from 10 to 80% by weight of demineralized water (IMP-TE-511.1); the second formulation contains from 2 to 20% by weight of 2-phosphonobutane, 1, 2,4-tricarboxylic acid; from 5 to 50% by weight of the organic copolymer KT-7800; from 5 to 50% by weight of the organic copolymer KT-2800; from 1 to 15% weight of monoethanolamine; from 2 to 50% by weight of phosphonoacetic hydroxy acid; from 10 to 50% by weight of potassium hydroxide and from 10 to 80% by weight of demineralized water (IMP-TE-511.2).
2. A semiorganic multifunctional chemical composition for the treatment of water with low calcium content and high stability index in cooling towers, in accordance with clause 1, characterized in that zinc chloride is incorporated as corrosion inhibitor specific for white metals which presents a synergistic effect with the organic corrosion inhibitor of the phosphonate type.
3. 3. - A semiorganic multifunctional chemical composition for the treatment of water with low calcium content and high stability index in cooling towers, in accordance with clauses 1 and 2, characterized in that it contains heavy metals, in this case the concentration being limited to lower values of 20 ppm in effluents from refineries and petrochemical plants.
4. 4. - A semiorganic multifunctional chemical composition for the treatment of water with low calcium content and high stability index in cooling towers in accordance with clauses 1 to 3, characterized in that it allows to increase up to 12 times the concentration of solids in cooling water , thus contributing to a significant saving in the spare water requirements in these equipment and consequently a decrease in the electric power consumption of the replacement water dosing equipment, because it contains in its formulation a mixture of a copolymer and A traceable terpolymer that is easy to control.
5. 5. - A semiorganic multifunctional chemical composition for the treatment of water with low calcium content and high stability index in cooling towers in accordance with clauses 1 to 4, characterized in that it presents high efficiency of inhibition to the incrustation, even in cooling systems , whose recirculation waters contain low concentrations in calcium salts and a high stability index. A semiorganic multifunctional chemical composition for the treatment of water with low calcium content and high stability index in cooling towers in accordance with clauses 1 to 5, characterized in that it maintains a low corrosion control in carbon stpipes. A semi-organic multifunctional chemical composition for the treatment of water with low calcium content and high stability index in cooling towers in accordance with clauses 1 to 6, characterized in that it allows to effectively disperse the low calcium content without causing its precipitation to favor high efficiency in heat exchange equipment.