WO2018119973A1

WO2018119973A1 - Hydrochloric acid pickling inhibitor and preparation method therefor

Info

Publication number: WO2018119973A1
Application number: PCT/CN2016/113342
Authority: WO
Inventors: 刘清华
Original assignee: 刘清华
Priority date: 2016-12-30
Filing date: 2016-12-30
Publication date: 2018-07-05

Abstract

Provided are a hydrochloric acid pickling inhibitor and a preparation method therefor. The hydrochloric acid pickling inhibitor is composed of the following components in parts by weight: 30 to 50 parts of a thiourea derivative, 15 to 30 parts of an alkali metal halide, 20 to 40 parts of an imidazoline derivative, 10 to 15 parts of a molybdate, 40 to 60 parts of a co-solvent, and 10 to 15 parts of water. The preparation method is as follows: adding deionized water and co-solvent to a three-necked flask; adding sequentially therein the thiourea derivative, the imidazoline derivative, and the alkali metal halide; inserting a thermometer into the reaction solution and heating same; and after the heating is stopped, adding molybdate into the flask, and stirring the mixture to uniformity and cooling to room temperature to obtain the hydrochloric acid pickling inhibitor.

Description

Hydrochloric acid pickling corrosion inhibitor and preparation method thereof

Technical field

The invention relates to the technical field of corrosion inhibitors, in particular to a hydrochloric acid pickling corrosion inhibitor and a preparation method thereof.

Background technique

Acidification is a technical measure that utilizes the dissolution and dissolution of acid cement on rock cement or formation pores, plugs in cracks, restores or improves gas layer permeability, and achieves gas well stimulation. In the acidification process of gas fields, there are widespread serious corrosion problems, which bring huge economic losses to production and lead to environmental pollution and other problems. In the process of pickling, the pipeline is inevitably corroded by acid. In order to reduce the damage of the metal material, a corrosion inhibitor is generally added.

At present, commonly used corrosion inhibitors are inorganic salts, organic amines, imidazolines and quaternary ammonium salts. Among them, inorganic salts are more toxic, and some phosphorus-containing compounds are prone to cause eutrophication of water bodies and cause damage to the environment. In the principle of environmental protection, it is extremely urgent to develop environmentally friendly corrosion inhibitors.

In recent decades, oil and gas fields containing corrosive media such as hydrogen sulfide and high salinity formation water have appeared one after another. The corrosion of equipment under acidic environment is serious, which has caused people to pay attention to anti-corrosion work. The imidazoline derivative is a heterocyclic compound obtained by dehydration of an organic amine and an organic carboxylic acid, and the nitrogen atom on the five-membered ring also has a lone pair of electrons, which can be combined with the empty 3d orbital of the iron atom on the metal, and then adsorbed on Metal surface that blocks the erosion of corrosive media. Imidazoline has a certain corrosion inhibition effect, and it is environmentally friendly and inexpensive. It has been developed into an imidazoline derivative corrosion inhibitor with different groups and has high application value. Compounding the imidazoline derivative with other types of corrosion inhibitors significantly improves the corrosion inhibition performance of the corrosion inhibitor.

Summary of the invention

The present invention aims to solve the above problems, and provides a hydrochloric acid pickling corrosion inhibitor which is compounded with a thiourea derivative, an imidazoline derivative, an alkali metal halide, a molybdate, etc., and has a corrosion inhibiting effect on a metal. Good, simple method, easy to control conditions, in line with the requirements of industrial production, the technical solutions adopted are as follows:

A hydrochloric acid pickling inhibitor consisting of the following parts by weight: 30-50 parts of thiourea derivative, 15-30 parts of alkali metal halide, 20-40 parts of imidazoline derivative, 10-15 parts of molybdic acid Salt, 40-60 parts of cosolvent and 10 to 15 parts of water.

On the basis of the above scheme, the hydrochloric acid pickling inhibitor consists of the following parts by weight: 35 parts of thiourea derivative, 20 parts of alkali metal halide, 25 parts of imidazoline derivative, 10 parts of molybdate, 50 parts. Cosolvent and 15 parts water.

Based on the above aspect, the thiourea derivative is a mixture of one or more of thiourea, diethylthiourea, phenylthiourea, and dithiourea.

Based on the above scheme, the alkali metal halide is a mixture of one or more of sodium chloride, potassium chloride, sodium bromide, potassium bromide, sodium iodide or potassium iodide.

Based on the above scheme, the imidazoline derivative is oleic acid amine ethyl imidazoline or oleic acid imidazoline.

Based on the above scheme, the molybdate is a compound of sodium molybdate or sodium molybdate and sodium tripolyphosphate.

Based on the above scheme, the mass ratio of sodium molybdate to sodium tripolyphosphate in the compound of sodium molybdate and sodium tripolyphosphate is (1.0 to 1.5):1.

Based on the above scheme, the co-solvent is one or more of ethanol, ethylene glycol, propanol, and glycerin.

The preparation method of the hydrochloric acid pickling corrosion inhibitor comprises the following steps: adding deionized water and a co-solvent to the three In the mouth flask, a thiourea derivative, an imidazoline derivative, and an alkali metal halide are sequentially added, and a thermometer is inserted into the reaction solution and heated. After the heating is stopped, the molybdate is added to the flask, stirred uniformly, and cooled to room temperature. A hydrochloric acid pickling inhibitor is obtained.

Based on the above scheme, the heating temperature is 40 to 50 ° C, and the heating time is 0.5 to 1 h.

The beneficial effects of the invention are:

Compared with the prior art, the compounded imidazoline type corrosion inhibitor is prepared by using a thiourea derivative as a raw material, an imidazoline derivative and a molybdate as a corrosion inhibitor, and the corrosion inhibitor has excellent corrosion inhibition performance. It can effectively reduce metal corrosion, harm to the natural environment, safe use, and improve the acidification effect of corrosion inhibitor. In addition, the use of the above raw materials for corrosion inhibitor preparation is simple, the conditions are easy to control, and meet the requirements of industrial production.

detailed description

The following examples further illustrate the invention:

The following is a detailed description of the present invention, but the following is merely a further explanation of the present invention, and is not intended to limit the scope of the present invention. The scope of the invention is to be construed as illustrative only and not as a limitation of the invention.

Example 1

15 g of deionized water and 50 g of a co-solvent were placed in a three-necked flask, and then 30 g of a thiourea derivative, 15 g of an alkali metal halide, and 30 g of an imidazoline derivative were sequentially added, and a thermometer was inserted into the reaction liquid and heated, and the heating temperature was 40 ～. At 50 ° C, the heating time was 0.5 to 1 h. After the heating was stopped, 10 g of molybdate was added to the flask, stirred uniformly and cooled to room temperature to obtain a hydrochloric acid pickling inhibitor, which was Product 1.

Example 2

15 g of deionized water and 50 g of a co-solvent were placed in a three-necked flask, and then 40 g of a thiourea derivative, 20 g of an alkali metal halide, and 30 g of an imidazoline derivative were sequentially added, and a thermometer was inserted into the reaction liquid and heated, and the heating temperature was 40 ～. At 50 ° C, the heating time was 0.5 to 1 h. After the heating was stopped, 10 g of molybdate was added to the flask, stirred uniformly and cooled to room temperature to obtain a hydrochloric acid pickling inhibitor, which was Product 2.

Example 3

15 g of deionized water and 50 g of a co-solvent were placed in a three-necked flask, and then 35 g of a thiourea derivative, 20 g of an alkali metal halide, and 25 g of an imidazoline derivative were sequentially added, and a thermometer was inserted into the reaction liquid and heated, and the heating temperature was 40 ～. At 50 ° C, the heating time was 0.5 to 1 h. After the heating was stopped, 10 g of molybdate was added to the flask, stirred uniformly and cooled to room temperature to obtain a hydrochloric acid pickling inhibitor, which was Product 3.

Example 4

15 g of deionized water and 50 g of a co-solvent were placed in a three-necked flask, and then 35 g of a thiourea derivative, 20 g of an alkali metal halide, and 20 g of an imidazoline derivative were sequentially added, and a thermometer was inserted into the reaction liquid and heated, and the heating temperature was 40 ～. At 50 ° C, the heating time was 0.5 to 1 h. After the heating was stopped, 10 g of molybdate was added to the flask, stirred uniformly and cooled to room temperature to obtain a hydrochloric acid pickling inhibitor, which was Product 4.

Example 5

15 g of deionized water and 50 g of a co-solvent were placed in a three-necked flask, and then 50 g of a thiourea derivative, 15 g of an alkali metal halide, and 20 g of an imidazoline derivative were sequentially added, and a thermometer was inserted into the reaction liquid and heated, and the heating temperature was 40 ～. At 50 ° C, the heating time was 0.5 to 1 h. After the heating was stopped, 10 g of molybdate was added to the flask, stirred uniformly and cooled to room temperature to obtain a hydrochloric acid pickling inhibitor, which was product 5.

Weight loss test

Experimental conditions: The test material was Q235a carbon steel, and the products obtained in the above Examples 1 to 5 were each dissolved in 1 M hydrochloric acid and dispersed by ultrasonic for 20 minutes. Then the Q235a carbon steel is immersed at a temperature of 15 ° C. Not in the above corrosion inhibitor, the experimental period was 24h.

Under the action of corrosion, the quality of the material will change systematically. This is the theoretical basis for measuring the corrosion resistance of materials by gravimetric method. The gravimetric method is widely used in laboratory and field experiments because it is simple and intuitive.

The weight loss method is based on the weight change of the material before and after corrosion to determine the corrosion rate. In order to facilitate the comparison and analysis of the data under different experimental conditions and different samples, the weight loss per unit area is usually expressed by the formula (1). Corrosion rate, the corrosion inhibition efficiency of the corrosion inhibitor on carbon steel can be obtained by formula (2).

Where: W ₀ - the mass of the test piece before immersion; W ₁ - the weight of the sample after the experiment and removal of the corrosion product; W ₂ - the blank sample corrects the weight loss; v - the corrosion rate of the sample; A - test Surface area; t - experimental period;

The polarization curve method can obtain the corrosion current of carbon steel. The greater the corrosion current, the more serious the corrosion condition. The corrosion inhibition efficiency of the corrosion inhibitor is obtained according to formula (3) by corrosion current, and the corrosion inhibition effect is evaluated.

IE - Corrosion inhibition rate of corrosion inhibitor; I _corr - Corrosion current density of material in corrosion inhibitor system;

I ⁰ _corr - the corrosion current density of the material in a blank corrosive medium;

The corrosion inhibition rates obtained by the weight loss method and the potentiodynamic polarization method are not very consistent. This is because the weight loss method measures the average corrosion rate over a period of time, while the potentiodynamic polarization measures the instantaneous corrosion rate.

Example 6

Conditions: The experimental material was Q235a carbon steel. The product 1 was dissolved in 1 M hydrochloric acid and dispersed by ultrasonic for 20 minutes to make the corrosion inhibitor concentration 100 mg/L. The Q235a carbon steel was then immersed in the above corrosion inhibitor at a temperature of 15 ° C for a test period of 24 h.

The corrosion inhibition efficiencies obtained by experimental tests were as follows: weight loss experiment 90.13%, dynamic potential polarization 85.40%, showing low corrosion rate and high efficiency corrosion inhibitor.

Example 7

Conditions: The experimental material was Q235a carbon steel, and the product 2 was dissolved in 1 M hydrochloric acid, and dispersed by ultrasonic for 20 minutes, and the concentration of the inhibitor was 100 mg/L. The Q235a carbon steel was then immersed in the above corrosion inhibitor at a temperature of 15 ° C for a test period of 24 h.

The corrosion inhibition efficiencies obtained by experimental tests were as follows: weight loss experiment 92.30%, dynamic potential polarization 83.44%, showing low corrosion rate and high efficiency corrosion inhibitor.

Example 8

Conditions: The experimental material was Q235a carbon steel, and the product 3 was dissolved in 1 M hydrochloric acid, and dispersed by ultrasonic wave for 20 minutes, and the concentration of the inhibitor was 100 mg/L. The Q235a carbon steel was then immersed in the above corrosion inhibitor at a temperature of 15 ° C for a test period of 24 h.

The corrosion inhibition efficiencies obtained by experimental tests were as follows: weight loss experiment 93.12%, dynamic potential polarization 82.10%, showing low corrosion rate and high efficiency corrosion inhibitor.

Example 9

Conditions: The experimental material is Q235a carbon steel, product 4 is dissolved in 1M hydrochloric acid, and dispersed by ultrasonic wave for 20 minutes. The concentration of the corrosion inhibitor is 100 mg/L. The Q235a carbon steel was then immersed in the above corrosion inhibitor at a temperature of 15 ° C for a test period of 24 h.

The corrosion inhibition efficiencies obtained by experimental tests were as follows: weight loss experiment 91.56%, dynamic potential polarization 84.32%, showing low corrosion rate and high efficiency corrosion inhibitor.

Example 10

Conditions: The experimental material was Q235a carbon steel, and the product 5 was dissolved in 1 M hydrochloric acid, and dispersed by ultrasonic wave for 20 minutes to make the corrosion inhibitor concentration 100 mg/L. The Q235a carbon steel was then immersed in the above corrosion inhibitor at a temperature of 15 ° C for a test period of 24 h.

The corrosion inhibition efficiencies obtained by experimental tests were as follows: weight loss experiment 90.06%, dynamic potential polarization 81.04%, showing low corrosion rate and high efficiency corrosion inhibitor.

The invention has been described above by way of example, but the invention is not limited to the specific embodiments described above, and any modifications or variations made in accordance with the invention are within the scope of the invention.

Claims

A hydrochloric acid pickling corrosion inhibitor characterized by comprising the following components by weight: 30-50 parts of thiourea derivative, 15-30 parts of alkali metal halide, 20-40 parts of imidazoline derivative, 10~ 15 parts of molybdate, 40-60 parts of cosolvent and 10 to 15 parts of water.
The hydrochloric acid pickling inhibitor according to claim 1, which is composed of the following parts by weight: 35 parts of a thiourea derivative, 20 parts of an alkali metal halide, 25 parts of an imidazoline derivative, and 10 parts of molybdenum. Acid salt, 50 parts co-solvent and 15 parts water.
The hydrochloric acid pickling inhibitor according to claim 1, wherein the thiourea derivative is a mixture of one or more of thiourea, diethylthiourea, phenylthiourea, and dithiourea. .
The hydrochloric acid pickling inhibitor according to claim 1, wherein the alkali metal halide is one of sodium chloride, potassium chloride, sodium bromide, potassium bromide, sodium iodide or potassium iodide. Several mixtures.
The hydrochloric acid pickling inhibitor according to claim 1, wherein the imidazoline derivative is oleic acid amine ethyl imidazoline or oleic acid imidazoline.
The hydrochloric acid pickling inhibitor according to claim 1, wherein the molybdate is a compound of sodium molybdate or sodium molybdate and sodium tripolyphosphate.
The hydrochloric acid pickling inhibitor according to claim 6, wherein the mass ratio of sodium molybdate to sodium tripolyphosphate in the compound of sodium molybdate and sodium tripolyphosphate is (1.0 to 1.5). ):1.
The hydrochloric acid pickling inhibitor according to claim 1, wherein the auxiliary solvent is one or more selected from the group consisting of ethanol, ethylene glycol, propanol and glycerin.
A hydrochloric acid pickling inhibitor according to any one of claims 1 to 8. The preparation method comprises the steps of: adding deionized water and a co-solvent to a three-necked flask, and then sequentially adding a thiourea derivative, an imidazoline derivative, an alkali metal halide, and inserting a thermometer into the reaction liquid and heating After the heating was stopped, the molybdate was added to the flask, stirred uniformly, and cooled to room temperature to obtain a hydrochloric acid pickling inhibitor.
The method for preparing a hydrochloric acid pickling inhibitor according to claim 9, wherein the heating temperature is 40 to 50 ° C and the heating time is 0.5 to 1 h.