SU477614A1 - Method of stabilization of cooling circulating water - Google Patents

Description

I

The invention relates to water treatment methods for industrial use, in particular the stabilization of circulating cooling water.

To prevent the precipitation of calcium carbonate salts from water, as well as to reduce the formation of biological deposits on the heat exchange surface and to reduce corrosion, the equipment under the action of cooling water uses various methods, such as pressure to water of sulfuric and hydrochloric acids, phosphates. Chlorination of water is used to combat biological sediment.

All these methods do not allow sufficient stabilization of circulating water: the addition of sulfuric and hydrochloric acids causes an increase in corrosion of the heat exchange apparatus, the use of phosphates does not allow to combat biological sediments, chlorination of water destroys algae, but does not affect biological sediments.

There is a method of stabilizing circulating cooling water by introducing chromium salt into them.

The disadvantages of this method are the high rates of formation

biological deposits and corrosion on the surfaces of heat exchange equipment. For example, with an initial water hardness of 7 mGEq / l and a dose of chromium salt of 50 mg / l, the rate of formation of biological deposits and corrosion is 0.46 and 0.04 g / m1 h, respectively.

In order to reduce the rate of formation of biological deposits and the rate of corrosion, carbamide is introduced simultaneously with the chromium salt. As a result, the rate of formation of biological deposits decreases to 0.12 g / m.h, and the corrosion rate to 0.02 g / m2-h with an initial water hardness of 7 mg eq / l and a dose of chromium salt 50 mg / l.

Example. Pre-prepare a 1.0% sodium dichromate solution and a 1% urea solution (urea-containing waste water can be used as a urea solution). The obtained solutions are introduced into the cooling circulating water in such an amount as to maintain the content of reagents in the circulating water at a constant level depending on the hardness of the circulating water: with a hardness of 5-8 mg eq / l bichromate - 50 mg / l, carbamide - 2 mg / l with hardness of 15-20 mg eq / l of dichromate - 200 mg / l, carbamide - 10 mg / l, the rate of formation of a biological comparison of the efficiency and the process of stabilization of water by known and proposed methods

The deposits and corrosion rate are determined by calculation.

Comparative data on the effectiveness of the process of stabilization of water by known and proposed methods are presented in the table.

Claims (1)

Invention Formula A method of stabilizing circulating cooling waters by introducing chromium containing salts, characterized in that, in order to reduce the rate of formation of biological deposits and the rate of corrosion, urea is introduced simultaneously with the chromium-containing salt.