RU2746727C1 - Asmol production method and anticorrosive insulating tape - Google Patents

Abstract

FIELD: pipeline systems.

SUBSTANCE: invention relates to the field of protection of the main pipelines from soil and electrochemical corrosion, in particular to a method for producing asmol for an anticorrosive material, as well as to anticorrosive insulating tapes for protecting main pipelines based on asmol. The method is carried out by the interaction of bitumen or asphalt propane tar deasphalting with dimethylformamide in the presence of sulfuric acid, with the following ratio of components, wt%: bitumen or asphalt propane tar deasphalting - 75-85, dimethylformamide - 3-5, sulfuric acid - the rest, in which at the first stage, bitumen or asphalt of propane tar deasphalting and dimethylformamide are mixed at a temperature of 120-130 °C for 1-1.5 hours. Then sulfuric acid is jetted to the resulting mixture at this temperature for 2-3 hours, ensuring that it is mixed with mixture in vertical and horizontal planes until the mixture temperature reaches 140-145 °С. Then, at the second stage, the temperature of the mixture is increased to 150-160 °С and stirred at this temperature for 1-1.5 hours to form the target product. The tape includes a base made of polymer tape, a mastic layer containing asmol and bitumen with the following ratio of components, wt%: bitumen - 10-30; asmol - the rest, as well as a release agent made of polyethylene terephthalate.

EFFECT: increasing the anticorrosive properties of the insulating tape and slowing down the corrosion process of metal pipelines.

2 cl, 2 tbl, 4 ex

Description

The invention relates to the field of protection of main pipelines from soil and electrochemical corrosion, in particular to a method for producing asmol for an anticorrosive material - asmol mastic, the raw material base of which are by-products of petrochemical industries, as well as anticorrosive insulating tapes based on asmol.

A known method of producing asmol in three stages by the interaction of bitumen or asphalt with an absorbent obtained in the production of butadiene, isoprene, isobutylene, in the presence of sulfuric acid, with the following ratio of components: 75-85 wt. % bitumen or asphalt deasphalting with propane; 8-22 wt. % absorbent and sulfuric acid - the rest. At the first stage, bitumen or asphalt is mixed with an absorbent at a temperature of 100-115 ° C, after which sulfuric acid is added to the reaction mixture for 5-6 hours until the temperature of the mixture reaches 120-130 ° C. In the second stage, the resulting mixture is stirred for 2-2.5 hours, then the temperature of the mixture is increased to 135-140 ° C, after which it is stirred for 4-5 hours. In the third stage, the temperature of the mixture is increased to 145-155 ° C and when this temperature is reached, the mixture is stirred for 4-6 hours with the formation of the target product (RU 2443751, IPC C10C 3/02, published on February 27, 2012).

The disadvantage of this method is the long duration of the technological process (3 stages, the total time is 19-20 hours), as well as the limited operating temperature range - up to + 40 ° C, since at high temperatures of the product pumped through the pipeline - up to + 60 ° C, occurs its draining from the walls of the pipeline.

A known method of producing anticorrosive mastic based on asphalt-resinous oligomers, including the interaction of bitumen with a heavy resin (bottoms of isoprene production of the stage of regeneration of dimethylformamide and sulfuric acid), and the process includes loading bitumen at a temperature of 130 ° C, dropping technical sulfuric acid 1.5-2 h at a temperature of 130 ° C. Then the product is stabilized at 150 ° C for 4 hours, additives are introduced - technical oil, butyl rubber, thermoplastic elastomer - at a temperature of 140 ° C. In this case, the components are constantly mixed after each cycle operation from 60 to 180 minutes. The process is carried out with the following ratio of components, wt. %: bitumen - 72-80; heavy resin - 2-3; technical sulfuric acid - 4-6; technical oil - 9-11; butyl rubber - 1-2; thermoplastic elastomer - 4-6 (RU 2407773, IPC S10S 3/02, published on December 27, 2010).

The disadvantage of this method is the low manufacturability of the process due to the fact that the bottom residue of the stage of regeneration of dimethylformamide is a viscous product and requires heating when loading into the reactor for the implementation of the method.

There is a known method for producing asmol (EA 021692, IPC C09D 195/00, C10C 3/02, published on 08/31/2015), which is designed to protect main pipelines with operating temperatures up to + 60 ° C. The method involves the interaction of bitumen or asphalt propane tar deasphalting with an absorbent obtained in the production of butadiene, isoprene, isobutylene, which is carried out in the presence of sulfuric acid in two stages: in the first stage, bitumen or asphalt is mixed with the absorbent at a temperature of 100-115 ° C, after which sulfuric acid is evenly sprayed into the reaction mixture at this temperature for 3-4 hours until the temperature of the mixture reaches 130-140 ° C, and in the second stage the temperature of the mixture is increased to 150-160 ° C and stirred for 4-6 hours, and for two hours before the end of the second stage, carbon black is added to the reaction mixture as a thixotropic additive, and the method is carried out with the following ratio of components, wt. %: bitumen or asphalt deasphalting with propane - 73-85, absorbent - 8-15, soot - 5-15, sulfuric acid - the rest.

This invention improves the manufacturability of the asmol production process, expands its thixotropic properties. However, it does not provide long-term preservation of anti-corrosion properties during operation.

Known anticorrosive insulating tape, including a base of a polymer tape, a mastic layer of asmol, additionally containing bitumen, and a release agent made of polyethylene terephthalate (RU 2199051, IPC F16L 58/04, published on 20.02.2003).

The disadvantage of this insulating tape is the low strength characteristics of the mastic layer due to the fact that its adhesive interaction with the metal is higher than the cohesive strength of the mastic itself. This leads to a redistribution of the mastic layer of the tape under the wrapper when the pipeline moves during operation, especially on pipelines with a temperature of the pumped product up to + 50 ° C, and, as a consequence, to insufficient reliability of the tape.

The closest technical solution is an anticorrosive insulating tape, including a base of a polymer tape, a mastic layer and an anti-adhesive, and the mastic layer contains asmol, bitumen, divinyl styrene thermoplastic elastomer, hydraulic oil as a plasticizer and carbon black in the following ratio of components, wt. %: bitumen - 10-30, divinylstyrene thermoplastic elastomer - 3-6, hydraulic oil - 10-15, carbon black - 10-20, asmol - the rest (ЕА 021691, IPC F16L 58/04, published on August 31, 2015).

This tape has good performance characteristics such as impact strength, adhesion, etc. However, the known anti-corrosion tape does not provide long-term retention of performance characteristics.

The objective of the invention is to provide a reliable anti-corrosion material and durable insulating tape to protect the main pipelines from soil corrosion.

The technical result of the invention consists in increasing the anticorrosive properties of the insulating tape and slowing down the corrosion process of metal pipelines by increasing the surface activity of the mastic based on the asmol produced by the proposed method.

The problem is solved and the technical result is achieved by the method of producing asmol by reacting bitumen or asphalt propane deasphalting of tar with dimethylformamide in the presence of sulfuric acid with the following ratio of components, wt. %: bitumen or asphalt of propane tar deasphalting - 75-85; dimethylformamide - 3-5; sulfuric acid - the rest, in which at the first stage bitumen or asphalt of propane deasphalting of tar and dimethylformamide are mixed in the specified amount at a temperature of 120-130 ° C for 1-1.5 hours, sulfuric acid is jetted to the resulting mixture at this temperature for 2-3 hours with the provision of stirring it with the mixture in the vertical and horizontal planes until the temperature of the mixture reaches 140-145 ° C, in the second stage the temperature of the mixture is increased to 150-160 ° C and stirred at this temperature for 1-1.5 hours with the formation of the target product.

The technical result is also achieved with an anti-corrosion insulating tape for protecting main pipelines, including a base made of polymer tape, a mastic layer containing asmol obtained by the proposed method, and bitumen, as well as an anti-adhesive made of polyethylene terephthalate, with the following ratio of the components of the mastic layer, wt%: bitumen - 10-30; asmol obtained by the proposed method - the rest.

The technical result of the invention is achieved due to the following.

_{Dimethylformamide (C 3} H ₇ ON) used in the preparation of asmol, which is a polar aprotic solvent, promotes the activation of the reactivity of sulfuric acid, which in turn promotes the formation of nitrogen-containing groups, which, together with sulfo groups from sulfuric acid, provide a complex interaction with bitumen. Considering that during underground corrosion of pipelines, electrochemical processes occur at the metal - electrolyte interface, there are two coupled processes: the transition of metal ions into solution - oxidizing or anodic, and the reverse - the transition of these ions from solution to the metal surface - reducing. Energy heterogeneity is obtained on the metal surface as a result of the formation of anode and cathode sections. In the proposed invention for leveling the energy inhomogeneity of the metal surface, a bifunctional insulating coating based on asmol is used. The sulfonic acid groups of asmol have acidic properties, while the nitrogen-containing groups of asmol have the main acceptor properties. Selectively sorbed on different-potential areas of the metal surface, they equalize their energetic inhomogeneity and provide high surface activity to the anticorrosive insulating material based on asmol. This leads to a decrease in the potential difference between the anodic and cathodic areas of the corrosive metal surface and, accordingly, to a slowdown or complete termination of the electrochemical corrosion process.

The method for producing asmol is carried out as follows.

A calculated amount of bitumen or asphalt of propane tar deasphalting, heated to a temperature of 120-130 ° C, is pumped into a reactor equipped with a stirring device and a jacket for heating, then the calculated amount of dimethylformamide is fed.

At the first stage, the specified components are thoroughly mixed for 1-1.5 hours, sulfuric acid is jetted to the resulting mixture at this temperature for 2-3 hours, while it is mixed with the mixture in the vertical and horizontal planes, ensuring the penetration of sulfuric acid into all layers and effective interaction with the reaction mixture until the temperature of the mixture reaches 140-145 ° C.

In the second stage, the temperature of the mixture is increased to 150-160 ° C and stirred at this temperature for 1-1.5 hours. The reaction mixture is stabilized with the formation of the target product.

Examples of implementation of the method

Example 1

The calculated amount of bitumen heated to 120 ° C and dimethylformamide were pumped into the heated reactor without preheating. Dimethylformamide (C ₃ H ₇ ON) is a finished product manufactured in accordance with GOST 20289. At the first stage, the mixture was stirred at 120 ° C for 1 hour. Then, to the obtained mass at the same temperature, the calculated amount of sulfuric acid was jetted into the reactor for 2 hours, thoroughly mixing it in the vertical and horizontal planes for complete and effective penetration into all layers of the reaction mixture, until the mixture temperature reached 140 ° C. In the second stage, the temperature of the mixture was raised to 150 ° C and stirred for 1 hour with the formation of the target product - asmol.

In the process, the components were used in the following ratio, wt. %: bitumen - 87; dimethylformamide - 5; sulfuric acid - 8.

Example. 2

The process of obtaining asmol at the first stage is similar to that described in example 1. At the second stage, the calculated amount of divinylstyrene thermoplastic elastomer was added to the mixture, the mixture was heated to a temperature of 150 ° C and stirred for 1 hour.

In the process of obtaining asmol, the components were used in the following ratio, wt. %: bitumen - 85; dimethylformamide - 5; divinylstyrene thermoplastic elastomer - 4; sulfuric acid - 6.

Example 3

The process of obtaining asmol in the first stage is similar to that described in example 1, but using asphalt instead of bitumen. At the second stage, the temperature of the mixture was increased to 155 ° C, the calculated amount of soot as a thixotropic component, rapeseed oil and divinylstyrene thermoplastic elastomer was added, stirred for 1.5 hours, and the process of obtaining asmol was carried out at the following ratio of components, wt. %: asphalt - 85; dimethylformamide - 4; soot - 3; rapeseed oil - 3; sulfuric acid - 5.

The authors also obtained asmol according to the given analogue - EA 021692, with the ratio of the components of the reaction mixture, wt. %: bitumen - 80; absorbent - 10; sulfuric acid - 5; soot - 5.

To compare the characteristics of asmol according to the analogue and the proposed invention, the following indicators were determined: the depth of penetration of the needle according to GOST 11501, the temperature of brittleness according to Fraas according to GOST 11507, water absorption and acidity. To compare the protective ability of mastic compositions according to GOST R 51164, their adhesion and the area of coating peeling during cathodic polarization were also determined.

The test results are shown in Table 1.

As can be seen from the data in table 1, asmol according to the proposed invention has a significantly higher corrosion resistance.

The technical result specified in the invention is also achieved by the proposed anticorrosive insulating tape, an essential distinguishing feature of which, in comparison with the prototype, is the content in the mastic layer of the tape of the component - dimethylformamide with nitrogen-containing groups, which, when interacting with sulfuric acid, improve the protective properties: strength characteristics, flexibility at minus 20 ° C, preservation of adhesion in an aggressive environment.

Anti-corrosion insulating tape is made as follows.

A melt of a mastic layer containing the mixture of components proposed in the invention is applied to the polymer base, then a release agent is applied over the mastic layer to prevent sticking when winding the tape into a roll. To protect the pipeline, it is wrapped with insulating tape, while in the process of wrapping, the release agent is removed from the surface of the mastic layer.

The mastic layer contains asmol obtained by the method according to the invention and bitumen. The ratio of the components specified in the essence of the invention is due to the following.

The optimal amount of bitumen is 10-30 wt. %. it is most expedient that, together with asmol, they mutually stabilize each other, which contributes to an increase in the durability of the tape. Adding less than 3% dimethylformamide to the mastic layer does not provide asmol with high surface activity and effective retardation of the electrochemical corrosion process. An increase in the content of dimethylformamide over 5% is impractical, because this practically does not change the surface activity of the mastic layer.

An example of the manufacture of anticorrosive insulating tape according to the proposed invention

The composition of the tape:

polymer base made of polyvinyl chloride tape (GOST 16272-79);

mastic layer containing, wt%: bitumen - 20; asmol obtained according to the method according to the invention - 80.

release agent based on polyethylene terephthalate grade AA-2 according to TU 5459-055-39160180-2000.

Was also made an insulating tape according to the prototype, the mastic layer of which contains, wt%: bitumen -10; thermoplastic elastomer - 6; plasticizer - 10; carbon black - 10; asmol-64.

To compare the protective ability of the obtained tapes, the following indicators were determined: softening temperature along the ring and ball according to GOST 11506, adhesion, coating strength on impact, tape flexibility at minus 20 ° C and adhesion stability in an aggressive environment for 30 days. The test results are presented in table 2.

As can be seen from the data in Table 2, the physical, mechanical and protective properties of the tape according to the proposed invention have improved performance:

- the softening temperature of the mastic layer on the tape is higher than in the prototype, this is due to an increase in the strength (cohesive) characteristics of the mastic;

- when checking the flexibility of the tape at minus 20 ° C, the formation of cracks and delamination is not observed, the tape is plastic with high strength properties;

- the adhesion of the tape is maintained for 30 days of holding the sample in a 3% NaCl solution, while according to the prototype, adhesion under these conditions decreases;

- the impact strength of the tape is higher according to the invention, which also confirms the higher protective properties.

Thus, the invention makes it possible to increase the anticorrosive properties of the insulating tape and significantly slow down the corrosion process of metal pipelines by increasing the surface activity of the mastic based on the asmol produced by the proposed method.

Claims (2)

1. A method of producing asmol by reacting bitumen or asphalt propane tar deasphalting with dimethylformamide in the presence of sulfuric acid at the following ratio of components, wt.%: Bitumen or asphalt propane tar deasphalting - 75-85; dimethylformamide - 3-5; sulfuric acid - the rest, in which at the first stage bitumen or asphalt of propane deasphalting of tar and dimethylformamide in the specified amount at a temperature of 120-130 ° C for 1-1.5 hours are mixed, sulfuric acid is jetted to the resulting mixture at this temperature for 2-3 hours with the provision of mixing it with the mixture in the vertical and horizontal planes until the temperature of the mixture reaches 140-145 ° C, at the second stage, the temperature of the mixture is increased to 150-160 ° C and stirred at this temperature for 1-1.5 hours with the formation of the target product. 2. Anticorrosive insulating tape for the protection of main pipelines, including a base made of polymer tape, a mastic layer containing asmol obtained according to claim 1, and bitumen, as well as a release agent made of polyethylene terephthalate, with the following ratio of the components of the mastic layer, wt%: bitumen - 10-30; asmol obtained according to claim 1 - the rest.