SU1016398A1 - Solution for cleaning thermal utility equipment - Google Patents

Abstract

SOLUTION FOR CLEANING HEAT AND ENERGY EQUIPMENT containing ethylenediaminetetraacetic acid disodium salt (, Trilon B) and hydrazine derivative, which is so important that, in order to increase the efficiency of cleaning, the solution contains as a hydrazine derivative a quit compounds., g / l; Trilon B3.0-20.0 phenylhydrazin0, 1-20.0

Description

§

SI

co: o

00

The invention relates to the chemical cleaning of metal surfaces of heat and power equipment: boilers, thermal, electrical stations, nuclear power plants.

Thermal equipment undergoes pre-start and periodic (operational) chemical cleaning.

Solutions for the purification of heat and power equipment are known, which contain ethylenediaminetetraacetic acid disodium salt (Trilon B) and organic acids: citric, tartaric, lactic, etc. one .

The closest to the proposed technical essence is solution 2, containing, by weight. %

Disodium salt

ethylenediaminete

Raacetic acid (Trilon B) 0.3-1.0

Monosubstituted

ammonium salt

citric acid1, 0-2.0

Hydrazine hydrate 0.1-0.5

Inhibitor 2-mercantobenzothiazole

(kaptax), 0, T-0,2

The pH of the solution is determined by solubility. Trilon B in acidic environments.

As inhibitors can be used catapin in an amount of 0.1-0.2 weight. % and OP-7 (OP-10) with catacomas in the amount of O, 1-0.2 and 0.005 wt.%, respectively.

The disadvantage of this solution is the low solubility of iron oxide deposits and the use of a scarce food product, citric acid.

The purpose of the invention is to increase the solubility of iron oxide deposits.

The goal is achieved by the fact that for the purification of heat and power equipment containing ethylene diamine tetraacetic acid disodium salt (Trilon B) and a hydrazine derivative, the solution contains phenylhydrazIN as a hydrazine derivative in the following ratio of components, g / l

Trilon B 3.0-20.0

Phenylhydrazine 0,1t20,0

The pH of the solution is determined by the solubility of Trilon 3 in acidic media and must not exceed 4.

The samples are cleaned chemically from Art. Z with factory mill scale, Trilon B solution with captaxoM and phenylhydrazine, and known solutions. Samples of Art. 3 are placed in a thermostated glass vessel, filled with a solution and kept at 95 ° C for 0.5 h. After that, the iron content is determined in the solution. The ratio of the volume of the solution and the treated surface in all experiments is 12.5

0 l / m

The test results are shown in table 1

The base of the upper limit of phenylhydrazine concentration is shown in

5 table.2, the lower limit is in table.3.

As can be seen from the table. 2 and 3, the presence of phenylhydrazine in the solution allows the Sc1 to significantly exceed the stoichiometric iron content of the thief containing Trilon B, which is a consequence of the dissolving ability of phenylhydrazine. Adding to the solution phenylhydrazine with a concentration of 0.1-20 g / l increases the rate of dissolution of iron oxides.

To determine the upper boundary value of the concentration of Trilon B, the dependence of the concentrations of dissolved iron on the concentration of Trilon B is determined at a pH value of 4.0. and. Phenylhydrazine concentration 0.1 g / l.

The data are given in table. four.

5 From table. 4, it can be seen that an increase in the rate of dissolution of iron oxides occurs with an increase in 1 of the concentration of Trilon B in the solution only to 20 g / l.

0 To determine the optimal pH value of the proposed solution. 25 ml of an aqueous solution containing 3 g / l is poured into thermostatted glass vessels.

5 Trilon B and 5 g / l of phenylhydrazine. The desired pH is set by adding sulfuric acid to the solution and monitored on a pH-242 pH meter. Then the solution is added

A weighed 200 mg of iron oxide (magnetite or hematite). The solution is kept at 98 ° C for 2 hours and then filtered from the undissolved part of the oxide powder. The filtrate defines

dissolved iron concentration. The dissolution data are given in Table 5.

From Table 5 it can be seen that at pH 4 a sharp decrease is observed

the rate of dissolution of iron oxides; therefore, chemical cleaning with a solution of Trilon B with phenylhydrazine should be carried out at a pH of not more than 4.

Thus, the proposed solution in comparison with the known increases the cleaning efficiency by 3.5. -5.6 times, the rate of dissolution of magnetite deposits by 3.5, and gematite

Solution

rilon B (Zg / l) + phenylhydrazine (0.1 g / l) F 2-mercaptobenzthiazole (0.2 g / l), PH 2.5

Trilon B (7 g / l) + phenyl hydrazine (10 g / l) + 2 mercaptobenztyazole (0.2 g / L), pH 2.75

TRILON B (10 g / l) phenylhydrazine (10 g / l) + captax (0.2 g / l)

Trilon B (20 g / l) + phenylhydrazine (20 g / l) + 2-mercaptobenzthiazole (O, 2 g / l), pH 2.8

Known Trilon B (3 g / l) + ammonium monocyte (10 g / l) h- hydrazine (1 g / l) + 2-mercaptobenzthiazole (0.2)

Trilon B (7 g / l) + monocitratammonium {15 g / l) + + hydrazine (3 g / l) + 2-mercaptobenethiazole (0.2 g / l). Trilon B (10 g / l) + monocyte E1mmonium (20 g / l) + hydrazine (5g / l) 2-mercaptobenzthiazole (0.2, g / l)

Iron oxide

1 oT0.45 .itl 2d- 1 - id-id

The concentration of Trilon i in solutions is 3 g / l.

that 5 times; reduces the cost of 1 m of solution, which makes it possible to reduce the cost of chemical cleaning of heat and power equipment from carbon steel by 2.5 times.

Table 1

The amount of removed sediments in terms of hematite, g / m

14.3

48.3 57.1

76,8

30.7

1.7.

34.3

37.3, 2.1

table 2

The concentration of dissolved iron, g / l, at a concentration of phenylhydrazine, g / l

Claims (1)

A SOLUTION FOR CLEANING HEAT POWER EQUIPMENT, containing disodium salt of ethylenediaminetetraacetic acid (Trilon B) and a hydrazine derivative, with the exception that, in order to increase the cleaning efficiency, the solution contains phenylhydrazine as a hydrazine derivative, in the following ratio of components, g / l: Trilon B 3.0-20.0 phenylhydrazine 0.1-20.0 s s oo