SU1130541A1 - Method for preventing deposition of inorganic salts - Google Patents

Abstract

1. THE METHOD OF PREVENTING THE DEPOSITION OF INORGANIC SALTS, including the introduction of surfactants into the circulating water, from-. characterized in that, in order to increase the effectiveness of the prevention of deposits and the destruction of previously formed scaling, a mixture of hydrolyzed synthetic fatty acids of the following composition is used as surfactants, wt.%: Isomeric sour 30–40 you are C20 - Normal acids 10–20 lots - Cjg Polymeric acids C Q 20 - 30 - C. 40 Dicarboxylic acids 2-10 - 40 Nonewashable Remaining substances C2o - (hydroperoxides, alcohols, aldehyde). 2. The method according to claim 1, about tl and h and y- S y and so that, the mixture of saponified synthetic fatty acids is introduced in an amount of 2.5 - 10 mg / l. : o o: l

Description

1 The invention relates to methods of preventing deposits in circulating water supply systems, mainly gas cleaning of metallurgical production. Methods are known to prevent carbonate deposits using various phosphate and organophosphate compounds IJ for water treatment. The disadvantages of these phosphate methods are that phosphate compounds do not prevent the formation of carbonate deposits, but only convert them into a loose, easily washable form. Moreover, the use of phosphates has a certain effect when alkalinity of circulating water is not more than 6 mg.eq./l. that in closed systems of water supply gas cleaning of metallurgical production practically does not occur. The closest technical solution to the invention is the method of preventing deposits of inorganic salts, including the introduction of surface-active substances into the circulating water, such as carboxylmethylcellulose lulose 2,. However, the known method does not effectively prevent scaling, reducing the growth rate of scaling. as well as the destruction of the formed deposits. The aim of the invention is to increase the effectiveness of preventing deposits and the destruction of previously formed deposits. The goal is achieved by the fact that according to the method of preventing deposits of inorganic salts, including the introduction of surfactants into the circulating water, and the latter use a mixture of saponified synthetic fatty acids of the following composition, wt.%: Isomeric 30 - 40 acids c / 20 28 Normal 10-20 C 20 - Cjg acids Polymeric 20 - 30 C acids - Dicarboxylic 2-10 acids C 0 - Nasilable Remaining substances 20 S (hydroperoxides, alcohols, aldehyde) 12 Moreover, the mixture of saponified synthetic fatty acids is introduced in an amount of 2 , 5 - 0 mg / l. The synthetic fatty acids washed with soda ash of the proposed composition are diluted with water to 0.1-2% concentration. An aqueous solution of saponified FFA with a dosing device is introduced into the circulating water in front of the settling equipment in the amount of 2.5-10 mg / l. The fatty acid soap molecules, which fall into the circulating water, combine with calcium bicarbonate dissolved in water, passivating it towards carbon dioxide and thereby preventing the formation of calcium carbonate. Unreacted molecules of fatty acid soaps get due to capillary forces into microcracks of previously deposited carbonate compounds and using propping pressure created in the capillaries, destroy them. As can be seen from the table.l, a high efficiency of preventing deposits (more than 90%) is achieved using a mixture of saponified synthetic fatty acids in the proposed colo worn, unsaponifiables role is to increase the term of protective effect of the organic film on the calcium-razovannoy mshami fatty acids on surfaces protected from salt deposits. Inclusion of unwashed substances into the composition of the mixture of saponified fatty acids allows the reagent to be periodically supplied without increasing the sediment growth rate due to the presence of unwashed substances. Table 2 shows data on the effect of the amount of mixture injected on the rate of destruction of previously formed scaling. From Table 2, it follows that the effect of destruction of previously formed deposits of inorganic salts occurs with the introduction of the proposed mixture in the amount of 2.5 and higher.

3 .1

Table 3 shows the comparative laboratory studies of the proposed method with the known. In the water coming from the blast furnace gas, with a pH of 7.5, alkalinity of 7.4 mg.eq./l, hardness of 12.5 mg.eq./l. Various amounts of a mixture of saponified synthetic fatty acids are introduced. The comparison is carried out with a known method with the introduction of carboxyl methylcellulose, fatty acids and alcohols.

Thus, the proposed method allows a drastic reduction in the rate of formation of deposits. However, the dosage of saponified FFA, less than 2 mg / l. insufficient because of the lack of fatty acids for stoichiometric binding of calcium ions, and the dosage of more than 10 mg / l is harmful due to the appearance of a side negative effect of suspension stabilization and deterioration of the quality of clarified water.

In the experiments, the results of which are given in Tables 2 and 3, a mixture of synthetic fatty acids of the following composition was used.

35% A + 15% B + 25% C + 5% D + 20% D.

Conducted industrial testing of the proposed method. A mixture of synthe305D1 ..4 was introduced into the circulating water supply system of the blast furnace gas purifiers of the metallurgical plant for 8 months.

tic fatty acids of the specified composition in the amount of 2.5 mg / l.

Before the introduction of these reagents into the system, trisodium phosphate was introduced in the amount of 2-3 mg / l in order to reduce the rate of formation of carbonate deposits. However, in the main conduits and equipment, although to a lesser extent, scaling is observed. After the introduction of new reagents during the first weeks of operation, the intensive destruction of monolithic carbonate sediments begins on the indicated equipment. Due to the destruction of deposits in the pressure pipelines of clarified water, their resistance decreased, which made it possible to reduce the number of pipelines that are constantly under load. The formation of new deposits in the water lines and equipment of the entire circulating water supply system of the gas treatment plant has completely stopped.

Thus, the application of the proposed method allows to achieve the effect of destruction and previously formed deposits.

The use of the invention will make it possible to solve the problem of sedimentation control not only in the metallurgical industries, but also in other branches of the national economy, providing a large economic effect.

Table 1

89 91 92 96 92 93 95 Weight fraction of acid, Z B Known method

Dosage reagent, mg / l

0.5

one

1.5

2

2.5

3

four

five

ten

- Continuation of table 1

table 2

The rate of sediment removal, g / m. h

32 36 37 37 37 The effect of preventing salt deposits,%

Without the introduction of reagents

Carboxylmethylcellulose, fatty alcohols and acids

Suggested Mixed Saponis

Table 3

Dense

60.0

2.5

Claims (2)

1. METHOD FOR PREVENTING SEDIMENTS OF INORGANIC SALTS, including the introduction of surfactants into the circulating water, from -. characterized in that, in order to increase the effectiveness of preventing deposits and the destruction of previously formed scaling, a mixture of saponified synthetic fatty acids of the following composition, wt.%: Isomeric acid You C _{2 ()} - Cgg Normal Kis- thirty - 40 lots with _{2 °} - with _2fl Polymer 10 - 20 acids C ^ _o - C ^ q Dicarboxylic 20 - thirty acids C ^ _o - C ^ _o Unsaponifiable 2 - 10 substances C ₂₀ - C _hell Rest (hydroperoxides, alcohols, aldehydes) 2. The method according to π. 1, characterized in that the mixture of saponified synthetic fatty acids is administered in an amount of 2.5-10 mg / l. 1 1130541 2