Oil-soluble corrosion inhibitor against hydrogen sulfide corrosion and preparation method thereof
By preparing an oil-soluble corrosion inhibitor with a specific composition and controlling its preparation process, a dense protective film is formed, which solves the problem of poor protective effect of existing corrosion inhibitors at high temperatures and achieves effective corrosion protection for oilfield equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 宜兴金兑化工有限公司
- Filing Date
- 2024-03-21
- Publication Date
- 2026-07-24
AI Technical Summary
Existing corrosion inhibitors are not effective at protecting oilfield equipment under high-temperature conditions and cannot effectively prevent hydrogen sulfide from corroding oilfield equipment. Furthermore, there is a lack of effective solutions for hydrogen sulfide corrosion.
An oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion is used, which contains a specific ratio of solvent, main agent, barium petroleum sulfonate, sodium benzoate and oxygen scavenger. By controlling the temperature, pressure and addition rate during the preparation process, a dense protective film is formed to ensure that the corrosion inhibitor effectively protects the metal surface under high temperature conditions.
Under high temperature conditions, corrosion inhibitors can effectively form a dense protective film, significantly improving the corrosion resistance of metal surfaces, protecting oilfield equipment, and the preparation method is economical and practical.
Smart Images
Figure CN118223029B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of corrosion inhibitor technology, specifically to an oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion and its preparation method. Background Technology
[0002] As oilfield development progresses, the generation of hydrogen sulfide gas is inevitable. The generation of hydrogen sulfide causes great corrosion problems to downhole tubing and tools, wellhead equipment, and above-ground gathering and transportation equipment and pipelines in the oilfield, directly threatening the safe and stable production of the oilfield. Moreover, the released hydrogen sulfide is a highly toxic substance that threatens people's health and safety.
[0003] Currently, the main technologies for controlling corrosion include: developing corrosion-resistant materials, adding corrosion inhibitors, and applying anti-corrosion coatings to the inner walls of existing equipment. Among these, corrosion inhibitors are the most economical, convenient, and effective method. However, there are currently no effective corrosion inhibitors for corrosion caused by hydrogen sulfide and its acids, and existing corrosion inhibitors have poor high-temperature resistance, resulting in inadequate protection when the produced fluid temperature is high. Summary of the Invention
[0004] To address the above problems, this invention provides an oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion and its preparation method.
[0005] The technical solution of the present invention is: an oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion, wherein the corrosion inhibitor comprises the following components by weight: 80-100 parts solvent, 30-45 parts main agent, 5-15 parts barium petroleum sulfonate, 10-15 parts sodium benzoate, and 3-8 parts oxygen scavenger.
[0006] The main agent comprises the following components by weight: 4-6 parts stearic acid, 5-8 parts hydroxyethyl ethylenediamine, 6-9 parts diethylamine phosphate, 5-7 parts methanol, and 10-15 parts toluene;
[0007] The preparation method of the main agent includes the following steps:
[0008] S1. Stearic acid and hydroxyethyl ethylenediamine are added to toluene and heated to 160-180°C with stirring until the toluene is completely evaporated to obtain the intermediate.
[0009] S2. Add the intermediate to diethylamine phosphate, place it in a reaction vessel and mix evenly. Then, heat the reaction vessel once, and add methanol to the diethylamine phosphate every 2-3 minutes during the first heating process. The initial amount of methanol added accounts for 15-20% of its total volume, and the amount of methanol added each time is 30-50% higher than the previous one, until the methanol is completely added. Then, stop the first heating and keep it at that temperature for 20-30 minutes. Then, heat the reaction vessel a second time until the temperature rises to 110-130°C and keep it at that temperature for 30-45 minutes to obtain a mixture.
[0010] S3. The mixture is subjected to vacuum distillation to obtain the main agent.
[0011] Note: The corrosion inhibitors mentioned above, when combined with other additives, can form a protective film on the metal surface. The protective film has a dense and stable structure, which can effectively prevent the metal surface from being corroded by hydrogen sulfide. Furthermore, the corrosion inhibitors mentioned above still have good corrosion inhibition performance under high temperature conditions, which can effectively protect oilfield equipment.
[0012] Furthermore, the solvent is kerosene or petroleum ether.
[0013] Note: The above solvents have good solubility, can adapt well to high-temperature environments, and have low cost, making them economical.
[0014] Further, the oxygen scavenger is any one or a mixture of diethylhydroxylamine, acetone oxime, or acetaldehyde oxime in any proportion.
[0015] Note: The oxygen scavengers containing the above-mentioned components can react with dissolved oxygen, effectively removing oxygen and preventing oxidative corrosion.
[0016] Furthermore, the heating rate for the first heating step is 4–6 °C / min.
[0017] Note: Limiting the rate of temperature increase in one go can prevent the temperature from rising too quickly, which could cause methanol to evaporate.
[0018] Furthermore, the heating rate of the secondary heating is 15–25 °C / min.
[0019] Note: Limiting the second heating rate can prevent the temperature from rising too quickly, which could lead to incomplete esterification.
[0020] Furthermore, the temperature of the vacuum distillation is 140–160°C, and the pressure is 2.4–2.8 kPa.
[0021] Note: The above vacuum distillation parameters ensure that byproducts can be removed during vacuum distillation.
[0022] On the other hand, the present invention provides a method for preparing an oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion, comprising the following steps:
[0023] Step 1: Divide the solvent into two equal parts, add the main agent completely into one part of the solvent, stir evenly, and obtain mixture A;
[0024] Step 2: Add barium petroleum sulfonate and sodium benzoate to another equal amount of solvent, stir until completely dissolved to obtain mixture B:
[0025] Step 3: Divide the oxygen scavenger into 2 to 4 equal parts. Then heat the mixture A to 50 to 60°C. While stirring, gradually add the mixture B to the mixture A. During the addition process, add one part of the oxygen scavenger to the mixture A every time the temperature of the mixture A drops by 3 to 5°C, until all the mixture B has been added, and the corrosion inhibitor is obtained.
[0026] Explanation: The above preparation method involves mixing solution A and solution B to make the internal composition of the corrosion inhibitor uniform. Then, by adding oxygen scavenger multiple times, the oxygen scavenger can be evenly distributed in the corrosion inhibitor, which improves the stability of the corrosion inhibitor and enables the corrosion inhibitor to form a uniform and dense protective film on the metal surface.
[0027] Furthermore, the amount of mixture B added per minute accounts for 10-20% of its total mass.
[0028] Note: Limiting the addition rate of mixture B can prevent mixture B from being added too quickly, which would cause mixture B to not be evenly distributed in mixture A.
[0029] The beneficial effects of this invention are:
[0030] (1) The corrosion inhibitor of the present invention, through the combination of the main agent and other additives, can form a protective film on the adsorbed metal surface. The protective film has a dense and stable structure, which can effectively prevent the metal surface from being corroded by hydrogen sulfide. Moreover, the above corrosion inhibitor still has good corrosion inhibition performance under high temperature conditions, which can effectively protect oilfield equipment.
[0031] (2) The preparation method of the present invention mixes mixture A and mixture B to make the internal components of the corrosion inhibitor uniform. Then, by adding oxygen scavenger multiple times, the oxygen scavenger can be evenly distributed in the corrosion inhibitor, which improves the stability of the corrosion inhibitor and enables the corrosion inhibitor to form a uniform and dense protective film on the metal surface. Attached Figure Description
[0032] Figure 1 This is a bar chart of corrosion inhibition rates under different corrosion inhibitor compositions in Experiment Example 1 of this invention;
[0033] Figure 2 This is a bar chart of corrosion inhibition rates under different main agent components in Experiment Example 2 of the present invention;
[0034] Figure 3 This is a bar chart of corrosion inhibition rate under different parameters for the preparation of the main agent in Experiment Example 3 of this invention;
[0035] Figure 4 This is a bar chart of corrosion inhibition rate under different heating rates in Experiment Example 4 of this invention;
[0036] Figure 5 This is a bar chart of corrosion inhibition rate under different parameters during the second heating in Experiment Example 5 of this invention;
[0037] Figure 6 This is a bar chart of corrosion inhibition rate under different parameters of vacuum distillation in Experiment Example 6 of this invention;
[0038] Figure 7 This is a bar chart of the corrosion inhibition rate under different preparation parameters of the corrosion inhibitor in Experiment Example 7 of this invention;
[0039] Figure 8 This is a bar chart showing the corrosion inhibition rate of mixture B at different addition rates in Experimental Example 8 of this invention. Detailed Implementation
[0040] To further illustrate the methods and effects of this invention, the technical solution of this invention will be clearly and completely described below in conjunction with experiments.
[0041] Example 1: An oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion, comprising the following components by weight: 90 parts solvent, 40 parts main agent, 10 parts barium petroleum sulfonate, 12 parts sodium benzoate, and 5 parts oxygen scavenger; wherein the solvent is kerosene and the oxygen scavenger is acetone oxime.
[0042] The main agent comprises the following components by weight: 5 parts stearic acid, 7 parts hydroxyethyl ethylenediamine, 7 parts diethylamine phosphate, 6 parts methanol, and 12 parts toluene;
[0043] The preparation method of the main agent includes the following steps:
[0044] S1. Stearic acid and hydroxyethyl ethylenediamine are added to toluene and heated to 160-180°C with stirring until the toluene is completely evaporated to obtain the intermediate.
[0045] S2. The intermediate is added to diethylamine phosphate and mixed evenly in a reaction vessel. The reaction vessel is then heated once, and methanol is added to the diethylamine phosphate every 2.5 minutes during the first heating process. The initial amount of methanol added accounts for 18% of the total volume, and the amount of methanol added each time is increased by 40% compared to the previous addition, until the methanol is completely added. The first heating is then stopped, and the temperature is maintained for 25 minutes. The reaction vessel is then heated a second time until the temperature reaches 120°C and is maintained for 40 minutes to obtain a mixture. The heating rate for the first heating is 5°C / min, and the heating rate for the second heating is 20°C / min.
[0046] S3. The mixture is subjected to vacuum distillation to obtain the main agent; wherein the vacuum distillation temperature is 150℃ and the pressure is 2.6kPa.
[0047] On the other hand, the preparation method of the above-mentioned corrosion inhibitor includes the following steps:
[0048] Step 1: Divide the solvent into two equal parts, add the main agent completely into one part of the solvent, stir evenly, and obtain mixture A;
[0049] Step 2: Add barium petroleum sulfonate and sodium benzoate to another equal amount of solvent, stir until completely dissolved to obtain mixture B:
[0050] Step 3: Divide the oxygen scavenger into 3 equal parts. Then heat the mixture A to 55°C and gradually add the mixture B to the mixture A while stirring. During the addition process, add one part of the oxygen scavenger to the mixture A for every 4°C decrease in temperature, until all of the mixture B has been added, and the corrosion inhibitor is obtained. The amount of mixture B added per minute accounts for 15% of its total mass.
[0051] Example 2: This example is basically the same as Example 1, except that the corrosion inhibitor includes the following components by weight: 80 parts solvent, 30 parts main agent, 5 parts barium petroleum sulfonate, 10 parts sodium benzoate, and 3 parts oxygen scavenger.
[0052] Example 3: This example is basically the same as Example 1, except that the corrosion inhibitor includes the following components by weight: 100 parts solvent, 45 parts main agent, 15 parts barium petroleum sulfonate, 15 parts sodium benzoate, and 8 parts oxygen scavenger.
[0053] Example 4: This example is basically the same as Example 1, except that the main agent includes the following components by weight: 4 parts stearic acid, 5 parts hydroxyethyl ethylenediamine, 6 parts diethylamine phosphate, 5 parts methanol, and 10 parts toluene.
[0054] Example 5: This example is basically the same as Example 1, except that the main agent includes the following components by weight: 6 parts stearic acid, 8 parts hydroxyethyl ethylenediamine, 9 parts diethylamine phosphate, 7 parts methanol, and 15 parts toluene.
[0055] Example 6: This example is basically the same as Example 1, except that methanol is added to diethylamine phosphate every 2 minutes during the heating process. The initial amount of methanol added accounts for 15% of its total volume, and the amount of methanol added each time thereafter is 30% higher than the previous one, until the methanol is completely added. Then the heating is stopped and the temperature is maintained for 20 minutes.
[0056] Example 7: This example is basically the same as Example 1, except that methanol is added to diethylamine phosphate every 3 minutes during the heating process. The initial amount of methanol added accounts for 20% of its total volume, and the amount of methanol added each time thereafter is increased by 50% compared to the previous one, until the methanol is completely added. Then the heating is stopped and the temperature is maintained for 30 minutes.
[0057] Example 8: This example is basically the same as Example 1, except that the heating rate for one heating cycle is 4℃ / min.
[0058] Example 9: This example is basically the same as Example 1, except that the heating rate for one heating cycle is 6℃ / min.
[0059] Example 10: This example is basically the same as Example 1, except that the reactor is then heated a second time until the temperature reaches 110°C and held for 30 minutes. The heating rate of the second heating is 15°C / min.
[0060] Example 11: This example is basically the same as Example 1, except that the reactor is then heated a second time until the temperature reaches 130°C and held for 45 minutes. The heating rate of the second heating is 25°C / min.
[0061] Example 12: This example is basically the same as Example 1, except that the temperature of vacuum distillation is 140°C and the pressure is 2.4 kPa.
[0062] Example 13: This example is basically the same as Example 1, except that the temperature of vacuum distillation is 160°C and the pressure is 2.8 kPa.
[0063] Example 14: This example is basically the same as Example 1, except that the oxygen scavenger is divided into two equal parts. Then, the mixture A is heated to 50°C, and while stirring, the mixture B is gradually added to the mixture A. During the addition process, one part of the oxygen scavenger is added to the mixture A for every 3°C decrease in temperature of the mixture A.
[0064] Example 15: This example is basically the same as Example 1, except that the oxygen scavenger is divided into 4 equal parts. Then, the mixture A is heated to 60°C, and while stirring, the mixture B is gradually added to the mixture A. During the addition process, one part of the oxygen scavenger is added to the mixture A for every 5°C decrease in temperature of the mixture A.
[0065] Example 16: This example is basically the same as Example 1, except that the amount of mixture B added per minute accounts for 10% of its total mass.
[0066] Example 17: This example is basically the same as Example 1, except that the amount of mixture B added per minute accounts for 20% of its total mass.
[0067] Experimental Example: To investigate the influence of parameters in each embodiment on the performance of the corrosion inhibitor, a high-salinity produced fluid was used as the corrosive medium. The salinity of the produced fluid was 2.63 × 10⁻⁶. 4The concentration of the corrosion inhibitor was 100 mg / L, the hydrogen sulfide content was 300 mg / L, the experimental material was N80 steel, the concentration of the corrosion inhibitor was 100 mg / L, the weight loss method was used, the test time was 48 h, the temperature was 120℃, and the corrosion inhibition rate of the corrosion inhibitor was calculated. The specific results are as follows:
[0068] 1. Investigate the effect of corrosion inhibitor composition on corrosion inhibition performance.
[0069] like Figure 1 As shown, commercially available KLSS type corrosion inhibitors were tested under the same corrosion conditions for 48 hours as Comparative Example 1. Comparing Examples 1, 2, and 3, it can be seen that: the corrosion inhibitor in Example 1 has the highest corrosion inhibition rate, reaching 98.24%. Therefore, Example 1 has the best corrosion inhibition performance, indicating that the corrosion inhibitor component selected in Example 1 is optimal. Comparing Example 1 with Comparative Example 1, it can be seen that: Example 1 has a higher release rate and better corrosion inhibition performance, indicating that the corrosion inhibitor in Example 1 has superior performance.
[0070] 2. Investigate the effect of the main component on corrosion inhibition performance.
[0071] like Figure 2 As shown, comparing Examples 1, 4, and 5, it can be seen that the corrosion inhibitor in Example 1 has the highest corrosion inhibition rate and the best corrosion inhibition performance, indicating that the main component selected in Example 1 is the optimal one.
[0072] 3. Investigate the influence of the preparation parameters of the main agent on the corrosion inhibition performance.
[0073] like Figure 3 As shown, with Example 1 as a reference, methanol was added all at once as Comparative Example 2. Comparison of Examples 1, 6, and 7 shows that the corrosion inhibitor in Example 1 has the highest corrosion inhibition rate and the best corrosion inhibition performance, indicating that the main agent preparation parameters selected in Example 1 are optimal. Comparison of Example 1 and Comparative Example 2 shows that Example 1 has a higher release rate and better corrosion inhibition performance, indicating that the methanol addition method selected in Example 1 is better.
[0074] 4. Investigate the effect of the initial heating rate on corrosion inhibition performance.
[0075] like Figure 4 As shown, a comparison of Examples 1, 8, and 9 reveals that the corrosion inhibitor in Example 1 has the highest corrosion inhibition rate and the best corrosion inhibition performance, indicating that the single heating rate selected in Example 1 is optimal.
[0076] 5. Investigate the effect of secondary heating parameters on corrosion inhibition performance.
[0077] like Figure 5 As shown, a comparison of Examples 1, 10, and 11 reveals that the corrosion inhibitor in Example 1 exhibits the highest corrosion inhibition rate and the best corrosion inhibition performance, indicating that the secondary heating parameters selected in Example 1 are optimal.
[0078] 6. Investigate the effects of vacuum distillation parameters on corrosion inhibition performance.
[0079] like Figure 6 As shown in the comparison of Examples 1, 12, and 13, it can be seen that the corrosion inhibitor in Example 1 has the highest corrosion inhibition rate and the best corrosion inhibition performance, indicating that the vacuum distillation parameters selected in Example 1 are optimal.
[0080] 7. Investigate the influence of corrosion inhibitor preparation parameters on corrosion inhibition performance.
[0081] like Figure 7 As shown, with Example 1 as a reference, the oxygen inhibitor was added all at once as Comparative Example 3. The comparison between Examples 1, 14 and 15 shows that the corrosion inhibitor in Example 1 has the highest corrosion inhibition rate and the best corrosion inhibition performance, indicating that the corrosion inhibitor preparation parameters selected in Example 1 are optimal. The comparison between Example 1 and Comparative Example 3 shows that Example 1 has a higher release rate and better corrosion inhibition performance, indicating that the oxygen inhibitor addition method selected in Example 1 is better.
[0082] 8. Investigate the effect of the addition rate of mixture B on corrosion inhibition performance.
[0083] like Figure 8 As shown in the comparison of Examples 1, 16, and 17, it can be seen that the corrosion inhibitor in Example 1 has the highest corrosion inhibition rate and the best corrosion inhibition performance, indicating that the addition rate of the mixed solution B selected in Example 1 is optimal.
Claims
1. A method for preparing an oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion, characterized in that, The preparation method of the corrosion inhibitor includes the following steps: Step 1: Divide the solvent into two equal parts, add the main agent completely into one part of the solvent, stir well, and you will get mixture A; Step 2: Add barium petroleum sulfonate and sodium benzoate to another equal amount of solvent, stir until completely dissolved to obtain mixture B: Step 3: Divide the oxygen scavenger into 2 to 4 equal parts. Then heat the mixture A to 50 to 60°C. While stirring, gradually add the mixture B to the mixture A. During the addition process, add one part of the oxygen scavenger to the mixture A every time the temperature of the mixture A drops by 3 to 5°C, until all the mixture B has been added, and the corrosion inhibitor is obtained. The amounts of each raw material in the corrosion inhibitor, by weight, are as follows: solvent 80-100 parts, main agent 30-45 parts, barium petroleum sulfonate 5-15 parts, sodium benzoate 10-15 parts, and oxygen remover 3-8 parts. The preparation method of the main agent includes the following steps: S1. Stearic acid and hydroxyethyl ethylenediamine are added to toluene and heated to 160-180°C with stirring until the toluene is completely evaporated to obtain the intermediate. S2. Add the intermediate to diethylamine phosphate, place it in a reaction vessel and mix evenly. Then, heat the reaction vessel once, and add methanol to the diethylamine phosphate every 2-3 minutes during the first heating process. The initial amount of methanol added accounts for 15-20% of its total volume, and the amount of methanol added each time is 30-50% higher than the previous one, until the methanol is completely added. Then, stop the first heating and keep it at that temperature for 20-30 minutes. Then, heat the reaction vessel a second time until the temperature rises to 110-130°C and keep it at that temperature for 30-45 minutes to obtain a mixture. S3. The mixture is subjected to vacuum distillation to obtain the main agent; The amounts of each raw material in the main agent, by weight, are as follows: stearic acid 4-6 parts, hydroxyethyl ethylenediamine 5-8 parts, diethylamine phosphate 6-9 parts, methanol 5-7 parts, and toluene 10-15 parts.
2. The method for preparing an oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion according to claim 1, characterized in that, The solvent is kerosene or petroleum ether.
3. The method for preparing an oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion according to claim 1, characterized in that, The oxygen scavenger is any one or a mixture of diethylhydroxylamine, acetone oxime, or acetaldehyde oxime in any proportion.
4. The method for preparing an oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion according to claim 1, characterized in that, The heating rate for each heating cycle is 4~6℃ / min.
5. The method for preparing an oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion according to claim 1, characterized in that, The heating rate for the secondary heating is 15~25℃ / min.
6. The method for preparing an oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion according to claim 1, characterized in that, The vacuum distillation is carried out at a temperature of 140~160℃ and a pressure of 2.4~2.8kPa.
7. The method for preparing an oil-soluble corrosion inhibitor for preventing hydrogen sulfide corrosion according to claim 1, characterized in that, The amount of mixture B added per minute accounts for 10-20% of its total mass.