RU2653745C1 - Method of protecting steel from corrosion in the mineralized aqueous phase of water-oil emulsions containing hydrogen sulfide - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to protection of metals against corrosion and can be used to protect equipment in the oil industry. Method comprises adding to the mineralized aqueous phase a water-oil emulsion of N-heptyl-1,4-phenylenediamine in a concentration of 50–200 mg/l.

EFFECT: increase the degree of steel protection from corrosion, reduce the corrosion rate of steel.

1 cl, 1 tbl, 3 ex

Description

The invention relates to a method for protecting metals from corrosion in the mineralized aqueous phase of oil-water emulsions with inhibitors and can be used in the oil industry to protect equipment in contact with the mineralized water phase of oil-water emulsions containing hydrogen sulfide from corrosion.

Known methods for protecting steel from corrosion in acidic environments using inhibitors based on aromatic and heterocyclic compounds, for example, such as catapines, which are alkylbenzylpyridinium chlorides that differ in the number of carbon atoms in the alkyl chain. The following brands of catapines are known: A, K, B-300, BPV, EPV (TU 6-01-530-70. Introduction. 06/01/1971.13 p.), A mixture of alkylbenzylpyridine and a cyclic amine (TU 6-46893387-34-90. Corrosion inhibitor KI-1. Introduced 01.07.90.12 p.). As well as other inhibitors: the condensation product of benzylamine with urotropine (TU 6-02-1192-79. Corrosion inhibitor BA-6. Introduction. 01.01.80.13 p.); a mixture of derivatives of toluene diisocyanates (TU 6-03-31-81. Corrosion inhibitor TDA. Introduced 01.02.82.13 p.); Quaternary pyridinium salt (TU 6-01-11-15-72. Corrosion inhibitor KPI-3. Introduced 01.02.73.14 p.).

However, these inhibitors do not have high protection efficiency in the mineralized aqueous phase of oil-water emulsions containing hydrogen sulfide.

The closest analogue in structure and effectiveness is the PB-5 corrosion inhibitor, which is a condensation product of aniline and urotropin (TU 6-01-28-92. The PB-5 corrosion inhibitor. Introduction. 01.01.93. 11 pp.). The disadvantage of this inhibitor is its low efficiency in the mineralized aqueous phase of oil-water emulsions containing hydrogen sulfide.

The problem to which the invention is directed, is to increase the efficiency of steel protection in the mineralized aqueous phase of oil-water emulsions containing hydrogen sulfide.

The claimed invention provides a method for protecting steel from corrosion in aqueous-oil media, comprising adding to the mineralized aqueous phase water-oil emulsions containing hydrogen sulfide, N-heptyl-1,4-phenylenediamine obtained according to [Abdrakhmanov IB Aromatic Kleisen amino rearrangement and conversion of ortho-alkenylarylamines. The dissertation for the degree of Doctor of Chemical Sciences, 1989. P. 205], in a concentration of 50-200 mg / l.

Tests of the protective effect of N-heptyl-1,4-phenylenediamine as a steel corrosion inhibitor in the mineralized aqueous phase of oil-water emulsions containing hydrogen sulfide were carried out under laboratory conditions by the gravimetric method in accordance with GOST 9.506-87 "Metal corrosion inhibitors in water-oil Wednesdays ”of the State Union of Standards of the SSR from 01.07.1988.

As working media, we used a mixture of a model of mineralized water (MMW) of the composition, g / l: NaCl - 163.00; CaCl ₂ ⋅ 6H ₂ O - 34.00; CaSO ₄ ⋅ 2H ₂ O - 0.14; MgCl ₂ ⋅6H ₂ O - 17.00 and oil prepared according to group 1 GOST 9965-76, in the ratio of 70:30. The hydrogen sulfide content was 1050 mg / L. As witness samples used plates of steel grade 3 (GOST 380-90).

Fat-free and dried to constant weight samples of steel grade 3 were placed in the working environment for 6 hours at 20 ° C with the addition of the proposed inhibitor and without it. After the aging time, the samples were thoroughly washed in a stream of water, immersed for 5-10 minutes in an alkali solution, washed again with running water and dried to constant weight. Next, the samples were weighed to the nearest 0.0002 g.

The corrosion rate (p), the degree of protection of steel against corrosion (Z) was determined in accordance with formulas (1) and (2):

where m ₁ -m ₂ - change in mass, g;

S is the sample area, m ² ;

t is the test time, h

where p ₁ is the corrosion rate in a medium without an inhibitor, g / m ² ⋅ h;

p ₂ - corrosion rate in an inhibited medium, g / m ² ⋅ h.

The essence of the claimed invention is confirmed by examples of specific performance.

Example 1. Synthesis of N-heptyl-1,4-phenylenediamine

To a solution of 32.4 g of 1,4-phenylenediamine (0.3 mol) in 100 ml of triethylamine, 40.35 g of heptyl chloride (0.3 mol) was added with stirring at room temperature. The resulting solution was stirred for 3-4 hours at 80 ° C. The solvent was removed by evaporation and the remaining reaction mixture was chromatographed on alumina using 5: 1 hexane-ethyl acetate mixture as eluent. Received 55 g of the product with a yield of 89.0%.

N-heptyl-1,4-phenylenediamine (1), Yield 55 g (89.0%).

IR spectrum (v, cm ^-1 ): 3375, 3430 (NH ₂ ). ¹ H NMR Spectrum (CDCl ₃ , δ / ppm): 0.84 (m, 3H, H-7 ', J = 13.4 Hz); 1.30 (m, 2H, H-6 '); 1.21 (m, 2H, H-5 '); 1.42 (m, 2H, H-4 '); 1.45 (m, 2H, H-3 '); 1.69 (m, 2H, H-2 '); 3.23 (broad s, 2H, NH ₂ ); 3.85 (m, 2H, H-1 '); 6.60 (m, 2H, H-2, H-6); 6.63 (m, 2H, H-3, H-5). ¹³ C NMR Spectrum (CDCl ₃ , δ / ppm): 14.0 (C-7 '); 22.35 (C-6 '); 31.65 (C-5 '); 29.0 (C-4 '); 25.87 (C-3 '); 29.0 (C ^{2 '} ); 67.90 (C-1 '); 113.60 (C-2, C-6); 115.85 (C-3, C-5); 139.85 (C-4); 153.9 (C-1).

Found%: C 85.02; H 6.50; N, 8.48. C ₁₃ H ₂₂ N.

Calculated%: C 85.12; H 6.55; N, 8.33.

Example 2

Testing the effectiveness of the protective effect of N-heptyl-1,4-phenylenediamine (1) as an inhibitor of steel corrosion was carried out according to the method described above.

, скорость коррозии без ингибитора составляет 0,83 г/м²⋅ч, а в присутствии 200 мг/л N-гептил-1,4-фенилендиамина (далее реагента) - 0,035 г/м²⋅ч. Степень защиты от коррозии в указанных условиях составляет 95,8%.In the water-oil mixture IIM: oil containing hydrogen sulfide

the corrosion rate without an inhibitor is 0.83 g / m ² ⋅ h, and in the presence of 200 mg / l N-heptyl-1,4-phenylenediamine (hereinafter referred to as the reagent), 0.035 g / m ² ⋅ h. The degree of corrosion protection under these conditions is 95.8%.

Example 3

, составляет 0,83 г/м²⋅ч без реагента и 0,47 г/м²⋅ч в присутствии 200 мг/л прототипа. Степень защиты в указанных условиях составляет 43,4%.Testing the effectiveness of the corrosion protection of the prototype (corrosion inhibitor PB-5) was carried out analogously to example 2. The corrosion rate in the water-oil mixture MMB: oil containing hydrogen sulfide

is 0.83 g / m ² ⋅ h without reagent and 0.47 g / m ² ⋅ h in the presence of 200 mg / l of the prototype. The degree of protection under these conditions is 43.4%.

The table shows the rest of the test examples of N-heptyl-1,4-phenylenediamine as an inhibitor of steel corrosion.

The test results shown in the table indicate the high efficiency of N-heptyl-1,4-phenylenediamine as an inhibitor of steel corrosion in the mineralized aqueous phase of oil-water emulsions containing hydrogen sulfide. The highest efficiency is achieved when the inhibitor concentration is from 50 to 200 mg / l. With an increase in inhibitor concentration above 200 mg / L, the degree of protection does not change significantly, and with a decrease in its concentration below 50 mg / L, a sharp decrease in the degree of protection is observed. In the case of the prototype at a concentration of 200 mg / l, the corrosion rate is 0.47 g / m ² ⋅ h in the mineralized aqueous phase of oil-water emulsions containing hydrogen sulfide, and the degree of protection is 43.4%.

The advantages of the proposed corrosion inhibitor of steel in comparison with the prototype are as follows.

1. A high degree of corrosion protection with N-heptyl-1,4-phenylenediamine (90.7-95.8%) compared with the prototype (43.4%).

2. The decrease in the corrosion rate of steel in the presence of N-heptyl-1,4-phenylenediamine by 11-24.0 times, and in the presence of the prototype - 1.8 times.

3. Effective dosages of the proposed inhibitor are 50-200 mg / l (degree of protection 90.7-95.8%), and in the prototype, even at dosages of 200 mg / l, the degree of protection does not exceed 43.4%.

The results allow us to conclude that the proposed method for protecting steel from corrosion in the mineralized aqueous phase of oil-water emulsions containing hydrogen sulfide, which can be used in the oil industry, is highly effective.

Claims (1)

A method of protecting steel from corrosion in the mineralized aqueous phase of water-in-oil emulsions containing hydrogen sulfide, comprising adding N-heptyl-1,4-phenylenediamine in a concentration of 50-200 mg / l to the mineralized water phase of the water-oil emulsion.