RU2452795C2 - Steel corrosion inhibitor in mineralised water phase of water-oil emulsions - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: inhibitor contains the following elements, in wt %: water ammonium or fluid ammonium - 8.98-13.2, allyl chloride or methallyl chloride 20.21 - 35.28, formaldehyde solution or paraformaldehyde - 7.93-11.70, and solvent, i.e. water-soluble spirit or water, or mix thereof - up to 100.

EFFECT: higher efficiency if inhibitors in water-oil emulsions containing hydrogen sulfide.

2 tbl, 3 ex

Description

The invention relates to the field of the protection of metals from corrosion in the mineralized aqueous phase of oil-water emulsions with inhibitors and can be used to protect against corrosion of equipment in contact with the mineralized water phase of oil-water emulsions containing hydrogen sulfide, i.e. in the oil industry.

Many corrosion inhibitors based on derivatives of formaldehyde, amines and various organic compounds are known: the condensation product of an amine with an aldehyde (TU 6-02-7-138-80. HMU inhibitor. Introduction. 01.01.80.13 s); mixtures of nitrogen-containing and formaldehyde-containing compounds (RU 2259424 C1, 08.28.2005); the condensation product of benzylamine with urotropine (TU 6-02-1192-79. Corrosion inhibitor BA-6. Introduced 01.01.80.13 s); a corrosion inhibitor containing an ethoxylated condensation product of alkyl phenols, polyalkylene-polyamines and formaldehyde (RU 2063478 C1, 02.25.1993); a composition consisting of a condensation product of mono- and dichlorophenols with formaldehyde and dimethylamine (RU 2092612 C1, 10/11/1995).

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 corrosion inhibitor B-2, which is a product of the condensation of ammonia and bottoms from the distillation of benzyl chloride with aldehyde (TU 6-01-147-67. "Corrosion inhibitor B-2" Introduction. 24.03.68. 11 from.)

The disadvantage of this inhibitor is its low efficiency in the mineralized aqueous phase of oil-water emulsions containing hydrogen sulfide.

The claimed technical solution is aimed at increasing the efficiency of steel corrosion inhibitors in the mineralized aqueous phase of oil-water emulsions containing hydrogen sulfide.

In the claimed technical solution, this is achieved by a composition for inhibiting corrosion of steel in the mineralized aqueous phase of oil-water emulsions, including ammonia - in the form of aqueous ammonia (25% aqueous solution) or liquid ammonia; allyl halide - allyl chloride or metal chloride, formaldehyde in the form of formalin or paraformaldehyde, and as a solvent - water-soluble alcohol or water, or a mixture thereof in the following ratio, wt.%:

Ammonia (aqueous ammonia or liquid ammonia) 8.98-13.2 Allyl halide (allyl chloride or metal chloride) 20.21-35.28 Formaldehyde (formalin or paraformaldehyde) 7.93-11.70 Water soluble alcohol, or water, or a mixture thereof up to 100

The composition is prepared as follows. The calculated amount of ammonia (aqueous ammonia or liquid ammonia), allyl chloride (allyl chloride or metal chloride) and the solvent are loaded into a mixer with a stirrer, and the mixture is stirred at a temperature of 35-45 ° C for 2-3 hours. Then, the calculated amount of formaldehyde (formalin or paraformaldehyde) is gradually introduced into the resulting mixture, followed by stirring for another 2-3 hours. The finished product has the following parameters.

Light brown to dark brown liquid.

The density of 0.999-1,053 g / cm ³ .

The pour point is from minus 31 ° to minus 45 ° C.

Testing the protective effect of the claimed composition as an inhibitor of steel corrosion in the mineralized aqueous phase of oil-water emulsions was carried out in laboratory conditions by the gravimetric method in accordance with GOST 9.506-87 "Inhibitors of metal corrosion in oil-water environments". As working media, a mixture of a model of mineralized water (MMW) and oil or a model of oil (hexane or heptane) in a ratio of 80:20 was used. A water-salt mixture of the composition, g / l: NaCl — 163.00; CaCl ₂ · 6H ₂ O — 34.00; MgCl ₂ · 2H ₂ O - 17.0; CaSO ₄ · 2H ₂ O — 0.14. The H ₂ S content was 1200 mg / L. Samples of steel grade 3 (GOST 380-90) were used as witness samples.

The tests were carried out as follows: in two glass vessels equipped with a mixing device and a lower tube with a tap, oil (or an oil model: hexane or heptane) and a solution of mineralized formation water in the prescribed ratio were poured, mixed for 5 minutes at a speed that ensured the formation of an emulsion . The studied inhibitor was dosed into one of the vessels and stirring was continued in both vessels for 30 minutes, after which the emulsion was settled until phase separation.

Fat-free and dried to constant weight samples of steel 3 were placed in the mineralized aqueous phases of water-oil emulsions obtained by the above method for 6 hours at 20 ° C. After the aging time, the samples were immersed for 5-10 minutes in an alkali solution, washed 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 corrosion protection of steel (Z) was determined in accordance with formulas (1) and (2)

where m1-m2 is the change in mass, g;

S is the sample area, m ² ;

t is the test time, h

where p1 is the corrosion rate in a medium without an inhibitor, g / m ² h;

P2 - corrosion rate in an inhibited medium, g / m ² h

The essence of the proposed technical solution is confirmed by examples of specific performance.

Example 1

8.98 g (8.98%) of liquid ammonia, 20.21 g (20.21%) of allyl chloride and 49.38 g (49.38%) of a solvent (39.38 g of water and 10 g of ethyl alcohol) are loaded into a mixer with a stirrer, stirred at a temperature of 35- 45 ° C for 2 hours. Then, 21.43 g (in terms of formaldehyde of 7.93%) of formalin are gradually introduced into the resulting mixture, followed by stirring for another 2 hours. The resulting product has the following parameters.

The liquid is brown.

Density - 0.999 g / cm ³ .

The pour point is minus 31 ° C.

Example 2

Testing the effectiveness of the protective effect of the obtained composition as an inhibitor of steel corrosion was carried out according to the method described above.

In the mineralized aqueous phase containing 1200 mg / l H ₂ S, the corrosion rate without inhibitor is 0.90 g / m ² h, and in the presence of 200 mg / l of the claimed composition (hereinafter reagent) - 0.018 g / m ² h

The degree of corrosion protection under these conditions is 98.0%.

Example 3

Testing the effectiveness of corrosion protection of the prototype (inhibitor B-2) was carried out analogously to example 2. The corrosion rate of steel in a saline aqueous phase with a content of H ₂ S of 1200 mg / l is 0.90 g / m ² h without reagent and 0.486 g / m ² h in the presence of 200 mg / l of the prototype. The degree of protection under these conditions is 46.0%.

Table 2 presents the rest of the test examples of the claimed composition as an inhibitor of steel corrosion.

The test results are shown in table 2, indicate the high efficiency of the claimed composition as an inhibitor of corrosion of steel in the mineralized aqueous phase of water-in-oil emulsions containing hydrogen sulfide. The highest protection efficiency is observed at ammonia concentrations in the composition from 8.98 to 13.25%. With a decrease in the ammonia content below 8.98%, the protection efficiency sharply decreases, and with an increase in the ammonia content above 13.25%, the protection efficiency does not significantly increase. The highest efficiency is achieved at a concentration of the claimed composition from 50 to 200 mg / L. With an increase in the concentration of the composition above 200 mg / L, the degree of protection does not change significantly, and with a decrease in the concentration of the composition below 50 mg / L, a sharp decrease in the degree of protection is observed.

Table 1 Examples of the preparation of corrosion inhibitor compositions No. Initial data for the preparation of the composition The indicators of the composition Songs Am Ag Fd P Color Density, g / cm ³ T st., ° C AB Already OH MAX F PFD VA Joint venture one 8.98 20.21 21.43 39.38 10.0 es Brown 0.999 -31 2 40 22.5 23.84 10.0 3.66 ms Dark box 1.015 -33 3 44.8 25.2 9.88 15.0 5.12 ps Light box 1.024 -35 four 12.2 32.47 08/29 13.0 13.25 es Brown 1.04 -39 5 13.25 35.27 31.62 10.0 9.86 ms Dark box 1.053 -43 6 * 32.0 18.0 08/19 15.0 15.92 es Light box 0.98 -thirty 7 * 14.0 37.26 33.38 7.0 8.36 ms Dark box 1.067 -45 Notes: Am - ammonia, AG - allyl halide; PD - formaldehyde; P is a solvent; AB - aqueous ammonia; АЖ - liquid ammonia; AH - allyl chloride; MAX - metal chloride; FA - formalin; PFD - paraformaldehyde; VA - water; SP - alcohol; ES - ethyl alcohol; MS - methyl alcohol; PS - propyl alcohol; 6 * and 7 * - transcendental values of the composition

table 2

Test Results of Corrosion Inhibitor Compositions

Example No. Composition number Inhibitor concentration, mg / l Corrosion rate, g / m ² h Degree of protection, % The control 0.90 2 one 200 0.018 98.0 3 prototype 200 0.486 46.0 four one one hundred 0.036 96.0 5 one fifty 0.0558 93.8 6 2 200 0.0216 97.6 7 2 one hundred 0.0423 95.3 8 2 fifty 0.0585 93.5 9 3 200 0.027 97.0 10 3 one hundred 0.09 95.2 eleven 3 fifty 0.0612 93.2 12 four 200 0.0171 98.1 13 four one hundred 0.0333 96.3 fourteen four fifty 0.0639 92.9 fifteen 5 200 0.0162 98.2 16 5 one hundred 0.0369 95.9 17 5 fifty 0.0603 93.3 eighteen 6 200 0.0126 86.0 19 6 one hundred 0.01962 78.2 twenty 6 fifty 0.0279 69.0 21 7 200 0.01755 98.05 22 7 one hundred 0.0351 96.1 23 7 fifty 0.0594 93.4 24 Prototype one hundred 0.576 36.0

The advantages of the claimed composition as an inhibitor of corrosion of steel compared with the prototype are as follows.

1. A high degree of corrosion protection of the claimed composition (92.9-98.2%) compared with the prototype (36.0-46.0%).

2. The decrease in the corrosion rate of steel in the presence of the claimed composition by 14-52.6 times, and in the presence of the prototype - 1.56-1.85 times.

3. Effective dosages of the claimed composition are 50-200 mg / l (degree of protection 92.9-98.2%), and in the prototype, even at dosages of 200 mg / l, the degree of protection does not exceed 46.0%.

The results obtained allow us to conclude that the claimed composition is an effective inhibitor of steel corrosion in the mineralized aqueous phase of oil-water emulsions containing hydrogen sulfide, i.e. may find application in the oil industry.

Claims (1)

Steel corrosion inhibitor in the mineralized aqueous phase of water-in-oil emulsions, characterized in that it contains ammonia in the form of ammonia of aqueous or liquid ammonia, allyl halide in the form of allyl chloride or metal chloride, formaldehyde in the form of formalin or paraformaldehyde and a solvent in the form of water-soluble alcohol or water or mixtures thereof, in the following ratio of components, wt.%:
ammonia water or liquid ammonia 8.98-13.2 allyl chloride or metal chloride 20.21-35.28 formalin or paraformaldehyde 7.93-11.70 water soluble alcohol or water or a mixture thereof up to 100