RU2544664C2 - Composition for removing mineral deposits - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: composition for removing mineral deposits contains nitrile trimethylene phosphonic acid, methylimino dimethylene phosphonic acid, hydrochloric acid and an acidic corrosion inhibitor. The inhibitor used is a mixture of 2-(8-heptadecynyl)-4,5-dihydro-1H-imidazole-1-ethylamine (HDHIA) and (Z)-N-[2-[(2-aminoethyl)amino]ethyl]-9-octadecenamide (AEODA), taken in ratio of 9:1 to 4:1, respectively.

EFFECT: high efficiency of removal of mineral deposits and reduced corrosive wear of equipment to standard values when using the composition to wash power-generation and process equipment.

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Description

The invention relates to the field of energy and can be used for chemical cleaning of technological equipment from deposits of sparingly soluble salts.

A known composition for removing deposits based on the mother liquor of the production of nitrile trimethylenephosphosonic acid (NTF) - diphalon (IM Dyatlova, V. Ya. Temkina, II Popov. Metal complexones and complexonates. M. Chemistry. 1988. 544 p. ) Difalon is produced according to TU 6-02-12-134-87. The composition is characterized by insufficient "capacity" to remove mineral deposits, a low rate of their dissolution.

Closest to the proposed one is a composition for removing mineral deposits, containing nitrile trimethylphosphonic acid (NTF), methylinodimethylenephosphonic acid (MNDF), hydrochloric acid, an acid corrosion inhibitor for PB-5 structural steel, and for brass - benzotriazole and water in the following ratio components, wt.%:

nitrile trimethylphosphonic acid (NTP) 14-16 methylinodimethylenephosphonic acid (MNDF) 4-7 hydrochloric acid 10-14 acid corrosion inhibitor 0.5-1

This composition is produced under the trade name "Ruston" in accordance with TU 2439-012-59945303-2009 (Patent RU No. 2177458. 2001).

However, this composition is also characterized by an insufficient dissolution rate of deposits, especially in cases of their uneven distribution on the metal surface.

In this case, various parts of the metal surface turn out to be free of deposits to various degrees, which, taking into account the dilution of the reagent to the working concentration (0.25-0.5 M) and the insufficient effectiveness of the corrosion inhibitors used, leads to a decrease in the “reagent capacity” (in In this case, the main components are partially spent on interaction with the metal) and, as a result, to increased corrosion wear of the equipment during washing. This, in turn, reduces the washing efficiency due to the time limit allocated to this process.

The objective of the invention and the expected technical result is the creation of a composition that allows to increase the washing efficiency by simultaneously increasing the rate of removal of salt deposits and reducing the amount of corrosive metal wear during the washing process.

This goal is achieved by the fact that to remove deposits use a composition containing nitrile trimethylene phosphonic (NTF), methyl iminodimethylene phosphonic (MNDF), hydrochloric acid, and as the active components of the acid corrosion inhibitor use a mixture of 2- (8-heptadecynyl) -4,5-dihydro 1H-imidazole-1-ethylamine C ₂₂ H ₄₃ N ₃ (GDGIEA):

and (Z) -N- [2 - [(2-aminoethyl) amino] ethyl] -9-octadecenamide C ₂₂ H ₄₅ N ₃ O (AEODA):

in a ratio of 9: 1 to 4: 1, respectively, as well as water in the following ratio of components, wt.%:

NTF 14-16 MNDF 4-7 hydrochloric acid 10-14 GDGIEA and AEODA in the ratio of 9: 1-4: 1 0.1-0.4 water rest

Introduction to the inventive composition of the mixture (GDGIEA and AEODA) in the claimed amounts and ratios provides a new technical result - an increase in the speed and number of removed deposits, a decrease in the corrosion rate under washing conditions.

The substances introduced into the claimed composition, namely 2- (8-heptadecynyl) -4,5-dihydro-1H-imidazole-1-ethylamine C ₂₂ H ₄₃ N ₃ (GDHIEA) and (Z) -N- [2 - (( 2-aminoethyl) amino] ethyl] -9-octadecenamide C ₂₂ H ₄₅ N ₃ O (AEODL) were previously known in science (see, for example, Bajpai Divya; Tyagi VK "SYNTHESIS OF FATTY IMIDAZOLINES BASED ON PALM FATTY ACIDS AND DIETHYLENETRIAMINE THROUGH MICROWAVE IRRADIATION AND THEIR CHARACTERIZATION "Heterocyclic Communications. Volume 13 (6). 2007. p. 77).

The claimed invention is illustrated by the following examples of specific performance.

Example 1

Samples of pipes with deposits (composition in terms of Fe ₂ O ₃ 32.1 oxides; CaO + MgO - 36.5; SiO ₂ - 11.3) with an outer diameter of 32 mm and an inner 23 mm layer of deposits (average 5 mm in inner diameter) and a width of 10 mm were suspended in a glass with a capacity of 500 ml, where a working solution was poured to remove deposits in a volume of 400 ml (80 ml of the composition was diluted to 400 ml with water in accordance with the analogue, prototype, and the proposed invention). The dissolution was carried out at room temperature without stirring due to the natural stirring released during the dissolution of carbon dioxide. Periodically, with an interval of 30 minutes, pipe samples were weighed on a technical balance. The washing efficiency was determined by the mass of deposits remaining on the sample after time t and was calculated by the formula:

E% = (Q ₀ -Q _t ) · 100 / Q ₀ ,%,

where Q ₀ is the mass of deposits before washing, g;

Q _t - mass of deposits during washing during time t, min.

Data on the effectiveness of washing are presented in table 1.

From the data presented in table 1, it can be seen that the use of a mixture of GDHIEA + AEODA in a ratio of 9: 1 to 4: 1, respectively, in amounts of 0.1-0.4% allows you to significantly increase the rate of removal of deposits. The greatest efficiency is observed when the ratio of the components GDHIEA + AEODA from 6: 1 to 4: 1. A decrease in the number of reagents GDGIEA + AEODA below 0.1% does not improve the processing efficiency but compared with the prototype, an increase in the number of GDGIEA + AEODA to 0.5%, with an optimal ratio of components, also does not lead to an improvement in the consumer properties of the composition, but the consumption of components GDGIEA + AEODA increases. In our opinion, the high efficiency when using the proposed technical solution is due to the fact that the presence of HDGEA + AEODA in it reduces the complexing and corrosion properties of the components of the composition - NTF, MNDF and hydrochloric acid. As a result, they are used only for its intended purpose - the removal of mineral deposits (pr. 8, 9, 10, 11, 12, 13).

The decrease in anti-corrosion properties of the composition is illustrated by the following example.

Example 2

The corrosion rate of compositions 1-16, named in table 1, was measured in solutions of compositions prepared to remove mineral deposits (diluted 5 times) according to the known method with an Expert 004 corrosion meter (see, for example, the magazine "Energy Saving and Water Treatment" B. N. Driker, S. L. Tarasova et al. No. 5. 2012, p. 2-5), on samples made from art. 3 and brass - 18. The data are shown in table 2.

From the data presented in table 2, it can be seen that the use of the proposed composition for washing energy and technological equipment allows not only to increase its effectiveness for removing mineral deposits, but also to reduce the corrosion wear of the equipment to standard values (less than 100 microns / year).

Claims (1)

Composition for removing mineral deposits containing nitrile trimethylene phosphonic (NTF), methyl iminodimethylene phosphonic (MNDF), hydrochloric acid and an acid corrosion inhibitor, characterized in that it contains a mixture of 2- (8-heptadecynyl) -4,5-dihydro-1H as an acid corrosion inhibitor -imidazole-1-ethylamine (HDGEA) and (Z) -N- [2 - [(2-aminoethyl) amino] ethyl] -9-octadecenamide (AEODA), taken in a ratio of from 9: 1 to 4: 1, respectively, in the following ratio of components, wt.%:
NTF 14-16 MNDF 4-7 hydrochloric acid 10-14 acid corrosion inhibitor GDGIEA + AEODA 0.2-0.4 water rest