LU102072B1

LU102072B1 - Method for performing plating to prevent pipe from sulfur corrosion

Info

Publication number: LU102072B1
Application number: LU102072A
Authority: LU
Inventors: Jinling Li; Shidong Zhu; Chengtun Qu; Tao Yu; Bo Yang; Yanfei Wang
Original assignee: Univ Xian Shiyou
Priority date: 2019-09-21
Filing date: 2020-09-21
Publication date: 2021-03-25
Also published as: CN110484946A

Abstract

The disclosure relates to the field of corrosion resistant pipes, and in particular to a method for performing plating on a pipe to prevent sulfur corrosion, comprising steps of: adding trichlorophenyl silane into anhydrous ether to form a homogeneous solution by stirring, into which distilled water is added dropwise to form a hydrolyzed solution; adding a dispersant, a filler, and a catalyst into the hydrolyzed solution to form a homogeneous plating solution by stirring; applying the plating solution uniformly onto an inner surface of the pipe by using a spray-roll method to carry out a reaction for 2 to 6 hours under an extrusion action at a constant temperature, so as to obtain a pipe with an inner plated surface; and subjecting the pipe with an inner plated surface to electroplating in an electroplating solution for 20 to 40 minutes to produce a pipe resistant to sulfur corrosion after drying. The problem with existing pipes that they have poor corrosion resistance to sulfur is resolved by the method. The rare earth alloy plating film stably formed on the inner wall of the pipe by using an alloy electroplating solution effectively improves the corrosion resistance to sulfur of the inner wall of the pipe.

Description

METHOD FOR PERFORMING PLATING TO PREVENT PIPE LU102072

FROM SULFUR CORROSION Technical Field The present disclosure is related to the field of corrosion resistant pipes, and in particular to a method for performing plating on a pipe to prevent sulfur corrosion. Background Sulfur corrosion is a typical problem faced by objects exposed to fuels or raw materials containing corrosive sulfur substances in fields such as aeronautical industry and energy industry. The corrosive sulfur substances may cause internal oxidation of the objects at relatively high temperatures such as higher than about 900 °C, and pitting corrosion of the surface of the objects at relatively low temperatures such as from about 600 to 900 °C. The internal oxidation and pitting corrosion may proceed at an unexpectedly fast speed and result in splits extending into the interior of base material of the objects, causing mechanical failure. Many attempts have been made to develop different processes for controlling sulfur corrosion. However, there is still a need for a new solution. Summary In view of the above problems, an objective of the present disclosure is to provide a method for performing plating on a pipe to prevent sulfur corrosion, which solves the problem with existing pipelines that they have poor resistance to sulfur corrosion. The method of the disclosure can improve the corrosion resistance to sulfur of the interior of the pipe by forming a rare earth alloy plated film, which is stable, on an inner wall or surface of the pipe using an alloy electroplating solution. The above objective of the present disclosure is realized by a method for performing plating on a pipe to prevent sulfur corrosion, comprising steps of: i. adding trichlorophenyl silane into anhydrous ether to form a homogeneous solution by stirring, into which distilled water is added dropwise to form a hydrolyzed solution; ii. adding a dispersant, a filler, and a catalyst into the hydrolyzed solution to form a homogeneous plating solution by stirring; 1 UT SS ri AA AAA AA iii. applying the plating solution uniformly onto an inner surface of the pipe by using a spray-rojl, 102072 method to carry out a reaction for 2 to 6 hours under an extrusion action at a constant temperature, so as to obtain a pipe with an inner plated surface; and iv. subjecting the pipe with an inner plated surface to electroplating in an electroplating solution for 20 to 40 minutes to produce a pipe resistant to sulfur corrosion after drying.

In the step (i), a concentration of the trichlorophenyl silane in the ether solution may be from 100 to 200 g/L, and the stirring may be carried out with a stirring speed of 1000 to 2000 rpm.

In the step (i), the distilled water may be added dropwise to the ether solution with a dropping rate of 5 to 8 mL/min and in a total amount of 5 to 7 times the moles of the trichlorophenyl silane.

In the step (ii), the dispersant may be added in an amount of 2 to 4 wt. % with respect to the amount of the trichlorophenyl silane. The dispersant may be sodium dodecyl sulfate. The catalyst may be aluminium silicate, and may be added in an amount of 5 to 7 wt. % with respect to the amount of the trichlorophenyl silane. The filler may be graphene, and may be added in an amount of 15 to 20 wt. % with respect to the amount of the trichloropheny!l silane. The stirring may be carried out with a stirring speed of 1500 to 3000 rpm.

In the step (iii), the spray-roll method may employ a pair of rollers: one front roller for spraying the plating solution in an amount of 40 to 80 mg/em”, and one rear extrusion roller operated at a constant temperature. The rear extrusion roller may be operated under an increased pressure of

0.4 to 0.7 MPa and at a temperature of 250 to 300 °C.

In the step (iii), the reaction may be carried out at a temperature of 240 to 280 °C under a pressure of 0.6 to 0.8 MPa.

In the step (iv), the electroplating may be carried out at a voltage of 15 to 30 Volts and a current of 300 to 600 Amps. The temperature of the electroplating solution may be maintained at from 70to 80 °C.

The electroplating solution used in the step (iv) may comprise 3 to 5 weight parts of aluminium nitrate, 3 to 8 weight parts of phosphoric acid, 8 to 10 weight parts of copper nitrate, 1 to 3 weight parts of a rare earth salt, and 50 to 80 weight parts of distilled water.

2

The method of the present disclosure may further comprise: subjecting the pipe produced in the 102072 step (iv) after drying to rare earth metal-copper plating in vacuum. The vacuum plating may be carried out at a temperature of 200 to 230 °C and a power of 1800 Watt under a pressure of 0.3 Pa. The method of the present disclosure may further comprise subjecting the pipe obtained in the step (iii) to a chemical cleaning process, which may comprise: a. subjecting the pipe obtained in the step (iii) to electrolytic degreasing in an electrolyte solution for 3 minutes and after the electrolytic reaction is complete, to be rinsed clean using purified water; and b. subjecting the pipe obtained in the step (a) to immersion treatment in anhydrous ethanol and then to be rinsed clean using an acid solution and purified water. The electrolyte solution used in the step (a) may be a mixed solution of sodium hydroxide and sodium carbonate at a concentration of 10 to 20 g/L and 20 to 30 g/L, respectively. The electrolytic degreasing may be carried out at 70 °C and a current density of 50 mA/cm®.

The acid solution used in the step (b) may be a mixed solution of hydrochloric acid, nitric acid, and water at a weight ratio of 3:3:14. According to the method of the present disclosure, trichlorophenyl silane is dissolved in ether and hydrolyzed to form a hydrolysate product. During the spray-roll process, the hydrolysate product is uniformly sprayed onto an inner surface of the pipe to form an uniform liquid film. A resin film is formed from the hydrolysate product due to the volatile nature of the ether. Pressing of the front roller enables formation of an uniform film layer. A portion of the ether that has permeated into interior of the film layer is removed by extrusion of the rear roller at a constant temperature. At the same time, sodium dodecyl sulfate is subjected to decomposition reaction, producing air bubbles. The subsequent extrusion of the rear roller allows the film layer to be compacted to ensure the tightness. Also, the temperature conditions and the action of the catalyst can result in highly crosslinked polycondensates. Thus, a stereostructure is formed, and aluminium silicate is bound within an internal space thereof. During the electroplating process, metal ions present in the electroplating solution are electrodeposited onto the surface of phenyl silicon. Graphene present in the phenyl silicon film may impart a good electroconductivity to the phenyl silicon film which itself is not electrically conductive. Thus, an uniform plating layer can be formed, which is attached only to a skin layer 3 of the phenyl silicon film. The optional subsequent vacuum plating step can enable formation 011102072 a copper-rare earth metal alloy layer, which provides corrosion resistance effect to the pipe. When being subjected to pitting corrosion caused by sulfuric acid, the copper itself enables formation of a protective film to suppress sulfuration, providing good effects on relieving corrosion. The rare earth metal and oxides among particles may form stable, dense rare earth oxides isolating the metals in the coating from the corrosive medium. Moreover, active sites on the surface of the coating can be reduced due to the purification action of the rare earth metal, thereby improving the corrosion resistance of the pipe. The front one of the optional pair of rollers may uniformly spray the coating onto the inner surface of the pipe, and the rear one subjects the coating on the inner surface of the pipe to extrusion and rolling processing conducted at a constant temperature. At the same time, the solvent in the coating can be removed under the effect of temperature, and leveling of the coating can be realized while the coating is in a liquid state. Further, the coating can be rapidly cured due to a temperature change. In the case that the pair of rollers are employed, a typical circular cross-sectional shape of the pipe may facilitate formation of uniform coatings through its uniform rotation. From the above description, it is apparent that the above-described embodiments have several advantages. - The problem with existing pipes that they have poor corrosion resistance to sulfur is resolved by the method of the present disclosure. The rare earth alloy plating film stably formed on the inner wall of the pipe by using an alloy electroplating solution effectively improves the corrosion resistance to sulfur of the inner wall of the pipe. - The phenyl silicon resin is used as an adhesive and improves the fastness of the alloy layer on the inner wall of the pipe. On the other hand, a porous network structure of the phenyl silicon substantially increases specific surface area and surface tension of the alloy layer, and can prevent the alloy layer from damage caused by flow impingement. - The copper-rare earth alloy coating formed by vacuum plating further improves corrosion resistance of the pipe. Detailed Description The embodiments of the present disclosure will be further described in detail with reference to examples, but the present disclosure is not limited to these examples. 4

EE EEE EEE

Example 1 APIS LU102072 A pipe was subjected to a plating process for corrosion prevention, which was carried out according to the following sequence of steps: i. trichlorophenyl silane was added into anhydrous ether and stirred until a homogeneous solution was formed, and thereafter distilled water was slowly added dropwise thereto to form a hydrolyzed solution; ii. a dispersant, a filler, and a catalyst were added into the hydrolyzed solution to form a homogeneous plating solution by stirring; iii. the plating solution was uniformly applied onto an inner surface of the pipe by using a spray- roll method to carry out a reaction for 2 hours under an extrusion action at a constant temperature, so as to obtain a pipe with an inner plated surface; and iv. the pipe with an inner plated surface was subjected to electroplating in an electroplating solution for 20 minutes to produce a pipe resistant to sulfur corrosion after drying.

In the step (i), the concentration of the trichlorophenyl silane in the ether solution was 100 g/L, and the stirring was carried out with a stirring speed of 1000 rpm.

In the step (i), the distilled water was added dropwise to the ether solution with a dropping rate | of 5 mL/min and in a total amount of 5 times the moles of the trichlorophenyl silane.

In the step (ii), the dispersant was added in an amount of 2 wt. % with respect to the amount of the trichlorophenyl silane. Sodium dodecyl sulfate was used as the dispersant. Aluminium silicate was used as the catalyst, and was added in an amount of 5 wt. % with respect to the amount of the trichlorophenyl silane. Graphene was used as the filler, and was added in an amount of 15 wt. % with respect to the amount of the trichlorophenyl silane. The stirring was carried out with a stirring speed of 1500 rpm.

In the step (iii), the spray-roll method employed a pair of rollers: one front roller for spraying the plating solution in an amount of 40 mg/cm? and one rear extrusion roller, which was operated at | a constant temperature. The extrusion roller was operated under 0.4 MPa and at 250 °C.

In the step (iii), the reaction was carried out at 240 °C under 0.6 MPa.

5

In the step (iv), the electroplating was carried out at 15 Volts and a current of 300 Amps. The 102072 temperature of the electroplating solution was maintained at 70 °C. The electroplating solution used in the step (iv) comprised 3 weight parts of aluminium nitrate, 3 weight parts of phosphoric acid, 8 weight parts of copper nitrate, 1 weight part of a rare earth salt, and 50 weight parts of distilled water. The pipe produced in the step (iv) after drying was subjected to rare earth metal-copper plating in vacuum. The plating was carried out at 200 °C and a power of 1800 Watt under 0.3 Pa. The pipe obtained in the step (iii) was subjected to a chemical cleaning process, which was carried out according to the following sequence of steps: a. the pipe obtained in the step (iii) was subjected to electrolytic degreasing in an electrolyte solution for 3 minutes and after the electrolytic reaction was complete, to be rinsed clean using purified water; and b. the pipe obtained in the step (a) was subjected to immersion treatment in anhydrous ethanol and then to be rinsed clean using an acid solution and purified water.

The electrolyte solution used in the step (a) was a mixed solution of sodium hydroxide and sodium carbonate at a concentration of 10 g/L and 20 g/L, respectively. The electrolytic degreasing was carried out at 70 °C and a current density of 50 mA/cm?.

The acid solution used in the step (b) was a mixed solution of hydrochloric acid, nitric acid, and water at a weight ratio of 3:3:14.

Example 2 A pipe was subjected to a plating process for corrosion prevention, which was carried out according to the following sequence of steps: i. trichlorophenyl silane was added into anhydrous ether and stirred until a homogeneous solution was formed, and thereafter distilled water was slowly added dropwise thereto to form a hydrolyzed solution; ii. a dispersant, a filler, and a catalyst were added into the hydrolyzed solution to form a homogeneous plating solution by stirring; 6 iii. the plating solution was uniformly applied onto an inner surface of the pipe by using a SprayT;402072 roll method to carry out a reaction for 6 hours under an extrusion action at a constant temperature, so as to obtain a pipe with an inner plated surface; and iv. the pipe with an inner plated surface was subjected to electroplating in an electroplating solution for 40 minutes to produce a pipe resistant to sulfur corrosion after drying. In the step (i), the concentration of the trichloropheny] silane in the ether solution was from 100 to 200 g/L, and the stirring was carried out with a stirring speed of 2000 rpm. In the step (i), the distilled water was added dropwise to the ether solution with a dropping rate of 8 mL/min and in a total amount of 7 times the moles of the trichloropheny! silane.

In the step (ii), the dispersant was added in an amount of 4 wt. % with respect to the amount of the trichlorophenyl silane. Sodium dodecyl sulfate was used as the dispersant. Aluminium silicate was used as the catalyst, and was added in an amount of 7 wt. % with respect to the amount of the trichlorophenyl silane. Graphene was used as the filler, and was added in an | amount of 20 wt. % with respect to the amount of the trichlorophenyl! silane. The stirring was carried out with a stirring speed of 3000 rpm.

In the step (iii), the spray-roll method employed a pair of rollers: one front roller for spraying the plating solution in an amount of 80 mg/cm? and one rear extrusion roller, which was operated at a constant temperature. The extrusion roller was operated under 0.7 MPa and at 300 °C. In the step (iii), the reaction was carried out at a temperature of 250 to 280 °C under 0.8 MPa. In the step (iv), the electroplating was carried out at 30 Volts and a current of 600 Amps. The | | temperature of the electroplating solution was maintained at 80 °C. The electroplating solution used in the step (iv) comprised 5 weight parts of aluminium nitrate, 8 | weight parts of phosphoric acid, 10 weight parts of copper nitrate, 3 weight parts of a rare earth | salt, and 80 weight parts of distilled water. | 25 The pipe produced in the step (iv) after drying was subjected to rare earth metal-copper plating in vacuum. The plating was carried out at 230 °C and a power of 1800 Watt under 0.3 Pa. | The pipe obtained in the step (iii) was subjected to a chemical cleaning process, which was carried out according to the following sequence of steps: | 7

EE a. the pipe obtained in the step (iii) was subjected to electrolytic degreasing in an electrolyte,4 92072 solution for 3 minutes and after the electrolytic reaction was complete, to be rinsed clean using purified water; and b. the pipe obtained in the step (a) was subjected to immersion treatment in anhydrous ethanol and then to be rinsed clean using an acid solution and purified water.

The electrolyte solution used in the step (a) was a mixed solution of sodium hydroxide and sodium carbonate at a concentration of 10 to 20 g/L and 20 to 30 g/L, respectively. The electrolytic degreasing was carried out at 70 °C and a current density of 50 mA/cm?.

Example 3 A pipe was subjected to a plating process for corrosion prevention, which was carried out according to the following sequence of steps: i. trichlorophenyl silane was added into anhydrous ether and stirred until a homogeneous solution was formed, and thereafter distilled water was slowly added dropwise thereto to form a hydrolyzed solution; ii. a dispersant, a filler, and a catalyst were added into the hydrolyzed solution to form a homogeneous plating solution by stirring; iii. the plating solution was uniformly applied onto an inner surface of the pipe by using a spray- roll method to carry out a reaction for 4 hours under an extrusion action at a constant temperature, so as to obtain a pipe with an inner plated surface; and iv. the pipe with an inner plated surface was subjected to electroplating in an electroplating solution for 30 minutes to produce a pipe resistant to sulfur corrosion after drying.

In the step (i), the concentration of the trichloropheny! silane in the ether solution was 150 g/L, and the stirring was carried out with a stirring speed of 1500 rpm.

In the step (i), the distilled water was added dropwise to the ether solution with a dropping rate of 6 mL/min and in a total amount of 6 times the moles of the trichloropheny! silane.

8 es |

In the step (ii), the dispersant was added in an amount of 3 wt. % with respect to the amount of 102072 the trichlorophenyl silane. Sodium dodecyl sulfate was used as the dispersant. Aluminium silicate was used as the catalyst, and was added in an amount of 6 wt. % with respect to the amount of the trichlorophenyl silane. Graphene was used as the filler, and was added in an amount of 18 wt. % with respect to the amount of the trichlorophenyl silane. The stirring was carried out with a stirring speed of 2500 rpm. In the step (iii), the spray-roll method employed a pair of rollers: one front roller for spraying the plating solution in an amount of 60 mg/cm? and one rear extrusion roller, which was operated at a constant temperature. The extrusion roller was operated under 0.6 MPa and at 280 °C.

In the step (iii), the reaction was carried out at a temperature of 250 to 280 °C under 0.7 MPa.

In the step (iv), the electroplating was carried out at 20 Volts and a current of 500 Amps. The temperature of the electroplating solution was maintained at 75 °C.

The electroplating solution used in the step (iv) comprised 4 weight parts of aluminium nitrate, 7 weight parts of phosphoric acid, 9 weight parts of copper nitrate, 2 weight parts of a rare earth salt, and 70 weight parts of distilled water.

The pipe produced in the step (iv) after drying was subjected to rare earth metal-copper plating in vacuum. The plating was carried out at 220 °C and a power of 1800 Watt under 0.3 Pa.

The pipe obtained in the step (iii) was subjected to a chemical cleaning process, which was carried out according to the following sequence of steps: a. the pipe obtained in the step (iii) was subjected to electrolytic degreasing in an electrolyte solution for 3 minutes and after the electrolytic reaction was complete, to be rinsed clean using purified water; and b. the pipe obtained in the step (a) was subjected to immersion treatment in anhydrous ethanol and then to be rinsed clean using an acid solution and purified water.

The electrolyte solution used in the step (a) was a mixed solution of sodium hydroxide and sodium carbonate at a concentration of 15 g/L and 25 g/L, respectively. The electrolytic degreasing was carried out at 70 °C and a current density of 50 mA/cm”.

The acid solution used in the step (b) was a mixed solution of hydrochloric acid, nitric acid, and water at a weight ratio of 3:3:14. 9

Performance Comparative Tests Performance Comparative Tests LU102072 The pipes produced in Examples 1-3 and an unplated pipe were immersed into a sulfur- containing wastewater having a sulfur concentration of 75 g/L.

Each of these pipes had a length of 5 meters. 10 L of the wastewater was circulated and passed through each of the pipes.

Results are shown in Table 1. Table 1 Comparative Example 1 Example 2 Example 3 Example Sulfur concentration 75 g/L 75 g/L 75 g/L 75 g/L before circulation Sulfur concentration after 74.9 g/L 74.9 g/L 74.9 g/L 723 gL circulation for 4 hours After circulation for 24 ; hours observed Therefore, the method according to the present disclosure has several advantages. - The problem with existing pipes that they have poor corrosion resistance to sulfur is resolved by the method of the present disclosure.

The rare earth alloy plating film stably formed on the inner wall of the pipe by using an alloy electroplating solution effectively improves the corrosion resistance to sulfur of the inner wall of the pipe. - The phenyl silicon resin is used as an adhesive and improves the fastness of the alloy layer on the inner wall of the pipe.

On the other hand, the porous network structure of the phenyl silicon substantially increases specific surface area and surface tension of the alloy layer, and can prevent the alloy layer from damage caused by flow impingement. - The copper-rare earth alloy coating formed by vacuum plating further improves corrosion resistance of the pipe.

It should be understood that the detailed description is intended for purposes of illustration only and is not intended to limit the scope of the present disclosure.

Those skilled in the art should appreciate that many changes can be made in the specific embodiments that are disclosed and still obtain a like or similar result without departing from the scope of the present disclosure. 10

Claims

CLAIMS LU102072 What is claimed is:

1. A method for performing plating on a pipe to prevent sulfur corrosion, comprising steps of: i. adding trichlorophenyl silane into anhydrous ether to form a homogeneous solution by stirring, into which distilled water is added dropwise to form a hydrolyzed solution; ii. adding a dispersant, a filler, and a catalyst into the hydrolyzed solution to form a homogeneous plating solution by stirring; iii. applying the plating solution uniformly onto an inner surface of the pipe by using a spray-roll method to carry out a reaction for 2 to 6 hours under an extrusion action at a constant temperature, so as to obtain a pipe with an inner plated surface; and v. subjecting the pipe with an inner plated surface to electroplating in an electroplating solution for 20 to 40 minutes to produce a pipe resistant to sulfur corrosion after drying.

2. The method according to claim 1, wherein, in the step (i), a concentration of the trichlorophenyl silane in the ether solution is in a range of from 100 to 200 g/L, and the stirring is carried out with a stirring speed of 1000 to 2000 rpm.

3. The method according to claim 1, wherein, in the step (i), the distilled water is added dropwise to the ether solution with a dropping rate of 5 to 8 mL/min and in a total amount of 5 to 7 times the moles of the trichloropheny! silane.

4. The method according to claim 1, wherein, in the step (ii), sodium dodecyl sulfate is used as the dispersant, and is added in an amount of 2 to 4 wt. % with respect to the amount of the trichlorophenyl silane; wherein, aluminium silicate is used as the catalyst and is added in an amount of 5 to 7 wt. % with respect to the amount of the trichloropheny! silane; wherein graphene is used as the filler and is added in an amount of 15 to 20 wt. % with respect to the amount of the trichlorophenyl silane; and wherein the stirring is carried out with a stirring speed of 1500 to 3000 rpm.

5. The method according to claim 1, wherein, in the step (iii), the spray-roll method employs a pair of rollers: one front roller for spraying the plating solution in an amount of 40 to 80 mg/cm? and one rear extrusion roller operated at a constant temperature, wherein the rear extrusion roller is operated under an increased pressure of 0.4 to 0.7 MPa, and at a temperature of 250 to 300 °C.

11 "77

6. The method according to claim 1, wherein, in the step (iii), the reaction is carried out at à U102072 temperature of 240 to 280 °C under a pressure of 0.6 to 0.8 MPa.

7. The method according to claim 1, wherein, in the step (iv), the electroplating is carried out at a voltage of 15 to 30 Volts and a current of 300 to 600 Amps, and wherein the temperature of the electroplating solution is maintained at from 70 to 80 °C.

8. The method according to claim 1, wherein, the electroplating solution used in the step (iv) comprises 3 to 5 weight parts of aluminium nitrate, 3 to 8 weight parts of phosphoric acid, 8 to weight parts of copper nitrate, 1 to 3 weight parts of a rare earth salt, and 50 to 80 weight parts of distilled water.

10

9. The method according to claim 1, further comprising: subjecting the pipe produced in the step (iv) after drying to rare earth metal-copper plating in vacuum.

10. The method according to claim 9, wherein, the rare earth metal-copper plating is carried out at a temperature of 200 to 230 °C and a power of 1800 Watt under a pressure of 0.3 Pa.

12 eee „ ——z——— —, — a»