RU2133229C1 - Method of prevention of scaling and fouling in water supply systems - Google Patents

Abstract

FIELD: methods of prevention of deposition of mineral salts and fouling in aqueous solutions; may be used in water treatment facilities in establishment of closed and without drainage water supply systems. SUBSTANCE: invention consists in that organophosphonates are used in the form of composition of inhibitor of scaling and its copper-containing complex. Scaling inhibitor and its complex with copper are used in their mole ratio of (5:1)-(1:1). EFFECT: higher efficiency of water treatment and reduced consumption of reagents. 2 tbl

Description

 The invention relates to methods for preventing deposits of mineral salts and biofouling in aqueous solutions and can be used in the field of water treatment to create closed and drainless water supply systems.

 Known methods of preventing deposits using organic polyphosphates [N.A. Meshchersky. Operation of water treatment in metallurgy. M., 1974, p. 137-139].

 Known methods are ineffective due to the hydrolysis of polyphosphates to orthophosphates and the formation of deposits of basic calcium phosphate.

 Closest to the proposed one is a method of preventing salt deposits by introducing organophosphonates into the water to be treated, which are aqueous solutions of complexones or mixtures thereof containing aminoalkylphosphonic groups [Copyright certificate SU N 474509, C 02 F 5/14, 1975].

 When using the known method in closed systems, where due to small amounts of recharge, the time for a complete replacement of water in the water supply system is more than 10 days, the biological destruction of organophosphonates occurs. These processes are especially strong when using water from open reservoirs due to the presence of organic substances of various origins. Thus, the known method is not effective enough and requires a large consumption of reagents.

 The objective of the invention is to increase the efficiency of water treatment in order to prevent the formation of salt deposits and biofouling in a closed water supply system, reducing the consumption of reagents for water treatment.

 The problem is achieved in that, in contrast to the known method of preventing salt deposits and biofouling, as organophosphonates use a mixture of an inhibitor of deposits of mineral salts (IOMS) and its copper-containing complex. To achieve maximum effect, a composition consisting of IOMS and its complex with copper is used at a molar ratio of 5: 1 -1: 1, respectively.

где n = 5 - 12
Выпускаются промышленностью по ТУ 6-05-2021-86.IOMS is a complexon containing aminoalkylphosphonic groups of the following structural formula:

where n = 5 - 12
Manufactured by industry according to TU 6-05-2021-86.

 The copper-containing IOMS complex is obtained by introducing a copper salt or hydroxide in the claimed ratio of components into the initial IOMS solution. The inventive method is illustrated by the following examples.

 Example 1

Water is subjected to treatment from the reverse cycle of the T-2 pipe-rolling workshop of the STD-400 furnace cooling system of the Seversky Pipe Plant with the following characteristics: total hardness - 9.2 mEq / l, alkalinity - 6.5 mEq / l, pH - 8 , 45, oil products - 1 mg / l, organic matter content - 20 mg / l (oxidizability according to KmnO ₄ ). The water is treated with IOMS reagents (according to the prototype) and the composition IOMS - copper complex IOMS (Cu - IOMS) with a molar ratio of 5: 1 to 1: 2, respectively. The concentration of the proposed reagents in total is 3 mg / L. The treated water with the introduced reagents is daily thermostated at a temperature of 70 ^o C for 2 hours, the rest of the time is kept at room temperature 18 ^o C for 14 days (the time of complete replacement of cooling water in the circulating system) in daylight. The effectiveness of preventing deposits is estimated by the formula
E = F _bp / W _ref • 100%
where W _bp - stiffness after the experiment, mEq / l;
W _ref is the hardness of the source water, mEq / L.

 The data obtained are given in table. 1.

 From the data presented in table. Figure 1 shows that the use of a reagent consisting of IOMS and its copper complex (Cu-IOMS), taken in a molar ratio of 5: 1 - 1: 1, can significantly increase the efficiency of water treatment in order to prevent the formation of deposits compared to using only IOMS reagent .

In our opinion, this is due to the fact that the presence of nitrogen and phosphorus molecules in the IOMS, the biochemical composition of the water used in the reverse system of the Seversky Pipe Plant, and experimental conditions contribute to the growth of bacteria (after six days the development of blue-green algae is observed). High efficiency when using the inventive reagent, consisting of IOMS and its copper complex, in our opinion, is due to their ratio and high stability of the copper complex IOMS - pK = 17.8 [N. M. Dyatlova et al. Metal complexones and complexonates, M Chemistry, 1988, p. 197]. Exceeding the declared IOMS: Cu-IOMS ratios leads to a decrease in processing efficiency. This may be due to the fact that the insufficient content the copper-containing complex IOMS: Cu-IOMS = 6: 1 does not sufficiently prevent salt deposition and biofouling (at the prototype level), and the excessive content of the copper-containing complex IOMS: Cu-IOMS = 1: 2 obviously leads to the formation of polynuclear poorly soluble complexon compounds decreasing x the presence in the treated solution of both IOMS and Cu ^{2+ ions} .

 Example 2

 To assess the effectiveness of preventing biofouling, the circulating water of the Seversky Pipe Plant is infected with microorganisms. Determination of effectiveness is carried out according to a standard method: water is poured into six equal portions. The analysis is carried out after 30 and 60 minutes. For this, a layer of water is removed by a siphon, and the precipitate is taken with a pipette and analyzed. The results are presented in table. 2.

 Of the presented in table. 2 data shows that the reagent, consisting of IOMS and its copper complex, taken in the claimed ratios effectively suppresses the vital activity of microorganisms and, obviously, prevents biofouling.

 As a result of using the proposed method of water treatment in closed systems, the effectiveness of protection against biofouling and scaling increases due to the mutual influence of the components on each other and, in addition, the costs associated with water treatment are reduced by a factor of 1.7-2.

Claims (1)

 A method of preventing salt deposits and biofouling in water supply systems by introducing an inhibitor of mineral salt deposits into the treated water, which use complexones containing aminoalkylphosphonic groups, characterized in that the inhibitor of mineral salt deposits additionally contains its copper-containing complex in a molar ratio of 5: 1 - 1 : 1 respectively.

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