RO105981B1 - Corrosion inhibitor for chemical removing of crvsts - Google Patents

Abstract

The invention relates to a corrosion used for corrosion protection of a machines subjected to the chemical washing process with hydrochloric or maleic acid solution up to 15% concentration. The corrosion inhibitor is soluble in water and acid solutions, consisting of 5 ... 20 pairs weight Mannich base, 10 ... 70 weight basis Mannich base ethoxylated with 8 ... 25 moles ethylene oxide, 5 ... 30 weight pairs hexamethylenetetramine, 1 ... 5 pairs weight of nonylphenol ethoxylated with 4 moles of ethylene oxide and 10 ... 40 weight of water. This inhibitor has action of wetting the crust on the machine, diffusion through crust pores and forming on the metal surface of a protective film.

Description

The present invention relates to the corrosion inhibitor, for chemical disincrustation, for the protection of metallic surfaces of technological equipment, heat exchangers, pipes, columns, vessels, etc.

It is known that the fastest and most advanced method for cleaning technological equipment, on which organic and inorganic products are deposited, is the chemical method. Depending on the nature of the construction material of the machines and the deposition on the metallic equipment, the chemical disassembly is performed inorganic acids (hydrochloric acid, sulfuric acid, phosphoric acid) or organic (citric acid, maleic acid, sulfamic acid, formic acid, acetic acid , amino acids) additives with corrosion inhibitors.

Among the corrosion inhibitors are known: bexamethylenetetrantine single or in combination with residues from the distillation of caprolaetam (RO Patent 51940) or with the sodium salt of a mixture of alkylaryl sulfonic acids (RO Patent 62691) ·, thiourea alone or in thiourea alone with urea (RO Patent No. 60065); phenyloxazoles (US Patent No. 4672118), amino acids, triumine, cistern, cystine (Japan Patent No. 62107092), amines, superior, acylated with naphthenic acids (RO Patent No. 65349), mixtures of organic amines, phosphonates and dispersing agents , N-pyridine compounds (US Patent No. 4672118), an acylated fatty amine mixed with triestersulfate and a low molecular weight triamine (RO Patent No. 90896), mixtures of alkylamines with aethyl alcohol and dialkylthiole (US Patent No. 4557878 ), polyalkylene derivatives of acetylene alcohols (DE patent no. 1939042), residues from cyclohexaneone distillation, purified with a NaOH solution: CH3OH (RO patent no. 71155) or mixed with nonionic surfactants (RO patent no. 75934).

The corrosion inhibitors, according to the present invention, extend the range of inhibitors used, as well as the antieorosive protection of the machines subjected to the chemical washing process, with hydrochloric or maleic acid solution of up to 15% concentration and are water soluble mixtures and acid solutions with action. wetting of the crust on the machine, of diffusion through the pores of the crust and of formation, on the metallic surface, of a protective film, consisting of 5 ... 20 parts weight base Mannich, 10 ... 70 parts weight base ethoxylated Mannich with 8 ... 25 moles of ethylene oxide, 5 ... 30 parts by weight hexamethylenetetraniine, 1 ... 5 parts by weight nonylphenol, ethoxylate I 3 ... 4 moles ethylene oxide and 10 ... 40 parts by weight water.

The corrosion inhibitor according to the invention has the following advantages:

- in acid solutions (hydrochloric acid, maleic acid, citric acid 2 ... 10%) it has the action of wetting the crust on the machine, diffusing through the pores of the crust and forming, on the metal surface, a protective film;

- the corrosion inhibition efficiency of carbon steel is 93 ... 98% at a 2 ... 10% HO concentration, at 25 ° C;

- the metallic surface, after pickling and washing, is clean and does not show corrosion.

The following embodiments of the invention are given:

Example 1. In a vessel with stirring system, 20 g of lxamethylenetetramine and 28 g of water are introduced. Stir until completely dissolved and continue for 30 minutes for mixing (solution A).

In another vessel provided with a stirring system, 40 of Mannich base, ethoxylated with 10 moles of ethylene oxide and 2 g of nonylphenol, ethoxylated with 4 moles of ethylene oxide are introduced. Stir for 30 minutes for homogenization, after which 10 g Mannich base, unethoxylated (solution B) is introduced.

After 30 minutes of stirring, solution A is gradually introduced over solution B, stirring for one hour. The homogeneous mixture obtained can be used as the original bad. -. · * So, or in dilution I water in a ratio of 1:] to 1: 10 for the inhibition of corrosion of carbon steel in 10% hydrochloric acid solution, in a proportion of 0.1%, the inhibition efficiency being 95%.

Example 2. 10 g hexamethylenetetraniine and 36 g water are introduced into a vessel with stirring system. After complete dissolution, it is homogenized for 30 minutes (solution A).

In another vessel provided with stirring system, introduce 45 g of Mannich base, ethoxylated with 25 moles of ethylene oxide and 4 g of nonoxyphenol ethoxylated with 4 moles of ethylene oxide. Stir for 30 minutes for homogenization, followed by the addition of 5 g Mannich, unethoxylated (solution B). After 30 minutes of stirring, solution B is gradually introduced, for 30 minutes, over solution A, stirring for one hour. The homogeneous mixture obtained can be used, as such, or in dilution with water in a ratio of 1: 1 to 1: 10 to inhibit corrosion of carbon steel, in a solution of 10% ntaleic acid (hydrochloric) in a dose of 0.2%, at temperature environment, with an efficiency of 93%.

EXAMPLE 3 In a vessel equipped with a stirring system, prepare, from 20 g hexamethylenetetramine and 28 g water, solution A. Further, while stirring, 40 g Mannich base, ethoxylate 25 mol ethylene oxide, 10 ml are introduced. g Mannich base and 2 g nonyl phenol, ethoxylated with 4 moles ethylene oxide. Shake, for homogenization, for 30 minutes, after which the mixture can be used to inhibit carbon steel corrosion, in solution

5 ... 10% hydrochloric acid (maleic) in a dose of 0.1%, at ambient temperature, with a 94% inhibition efficiency.

Claims (1)

Corrosion inhibitor, for chemical disintegration, soluble in water or acid solutions, characterized in that it consists of 5 ... 20 parts by weight 20 tonnes Mannich base, 10 ... 70 parts weight Mannich base, ethoxylated with 8 ... 25 moles of ethylene oxide, 5 ... 30 parts by weight hexamethyltetranine, 1 ... 5 parts by weight noniphenol, ethoxylate with 3 ... 4 moles oxide 25 ethylene and 10 ... 40 parts by weight of water, the inhibitor being used concentrated or diluted with water, in a ratio of 1: 1 to 1: 10 parts by weight.