A high-temperature corrosion inhibitor for macromolecular sulfur-phosphorus composite crude oil distillation equipment: its preparation method and applications.
By preparing a macromolecular sulfur-phosphorus composite corrosion inhibitor, the problems of high phosphorus content and large dosage in high-temperature corrosion inhibitors have been solved, achieving low-cost and high-efficiency corrosion inhibition, which is suitable for high-temperature petroleum refining units.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHENYANG UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2024-11-22
- Publication Date
- 2026-06-30
AI Technical Summary
Existing high-temperature corrosion inhibitors contain high levels of phosphorus, which can easily lead to catalyst poisoning. Non-phosphorus corrosion inhibitors require large amounts and have poor effects, making it difficult to meet environmental protection requirements and the need for efficient corrosion inhibition.
A high-temperature corrosion inhibitor for crude oil distillation equipment using a macromolecular sulfur-phosphorus composite is developed. It is prepared by reacting phenylphosphonic dichloride, acetonitrile, ethylene amine, thiourea and fatty acids in a specific ratio to form a low-phosphorus corrosion inhibitor containing sulfur, which is suitable for high-temperature corrosive environments.
It achieves high-efficiency corrosion inhibition under low phosphorus content, requires small dosage, has low cost, and is suitable for high-temperature corrosive environments, especially oil refining units in the range of 200-400℃, with a corrosion inhibition rate of over 90%.
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Figure CN119528982B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to corrosion inhibitor technology, and more particularly to a high-temperature corrosion inhibitor for a macromolecular sulfur-phosphorus composite crude oil distillation unit, its preparation method, and its application. Background Technology
[0002] High-temperature naphthenic acid and sulfur corrosion are unavoidable problems encountered in the petroleum refining process. High-temperature corrosion has long been one of the major technical challenges in crude oil refining, and with the increase in the acid value of crude oil refining feedstocks in recent years, the problem of high-temperature corrosion has become increasingly serious. This is especially true for marine naphthenic crude oil, which is characterized by high density, high acid value, and high salt content. Corrosion in atmospheric and vacuum distillation units is divided into low-temperature corrosion (below 120℃) and high-temperature corrosion (240-480℃), with naphthenic acid corrosion and high-temperature sulfur corrosion being the main types. High-temperature corrosion often leads to corrosion damage to refining equipment systems and pipelines. The corrosion sites are mainly at the outlet of the atmospheric and vacuum distillation furnace, the transfer line between atmospheric and vacuum distillation units, the tower wall of the feed section of the atmospheric and vacuum distillation tower, and the vacuum distillation line 3. These corrosion sites are characterized by high flow velocities, easy formation of eddies, and large scouring forces. This corrosion seriously affects the safe production of the refinery and the long-term operation of the units.
[0003] To mitigate the impact of naphthenic acid corrosion on equipment, refineries can take measures such as crude oil deacidification, using naphthenic acid-resistant materials in equipment, and adding high-temperature corrosion inhibitors. Due to the low cost and high effectiveness of adding corrosion inhibitors, refineries commonly adopt this method to reduce naphthenic acid corrosion in high-temperature areas. High-temperature corrosion inhibitors used domestically and internationally are mainly divided into two types: phosphorus-based and non-phosphorus-based. Phosphorus-based corrosion inhibitors are primarily organic compounds containing phosphoric acid or phosphorous acid groups. Phosphorus-based corrosion inhibitors can react with metallic iron to form oil-insoluble substances, creating a chemical protective film on the metal surface, isolating the metal from contact with corrosive substances such as naphthenic acids. Non-phosphorus-based high-temperature corrosion inhibitors, with their polar molecules or atoms forming a physical adsorption film with iron, adsorb onto the metal surface, thus achieving the purpose of isolating the metal from naphthenic acids and protecting it. In terms of corrosion inhibition effect, phosphorus-based corrosion inhibitors, due to the formation of a chemical adsorption film, are significantly more effective than non-phosphorus-based corrosion inhibitors in forming a physical adsorption film. However, most high-temperature corrosion inhibitors currently available are phosphorus-based. While phosphorus-based inhibitors offer the advantages of low dosage and high inhibition rate, they contain harmful phosphorus elements, which can decompose at high temperatures, leading to catalyst poisoning, environmental pollution, and corrosion problems in subsequent refinery processes. Currently, petrochemical companies such as Sinopec and PetroChina have begun to restrict the use of phosphorus-based high-temperature corrosion inhibitors. Non-phosphorus-based inhibitors do not contain harmful elements, but they generally suffer from high dosage and poor corrosion inhibition effects. Therefore, developing a composite high-temperature corrosion inhibitor with low phosphorus content and high efficiency has become an urgent task. Summary of the Invention
[0004] The purpose of this invention is to address the problems of high phosphorus content in current phosphorus-containing corrosion inhibitors, which easily poison downstream processing catalysts, and the poor corrosion inhibition effect of phosphorus-free high-temperature corrosion inhibitors, which require large dosages. This invention proposes a macromolecular sulfur-phosphorus composite high-temperature corrosion inhibitor for crude oil distillation units. This inhibitor has low phosphorus content, contains sulfur, and features low dosage, high corrosion inhibition rate, low cost, and ease of production. It has excellent application prospects and large-scale industrial application potential in the field of crude oil distillation units.
[0005] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," "consisting of," etc., and similar meanings.
[0006] To achieve the above objectives, the technical solution adopted by this invention is: a high-temperature corrosion inhibitor for a macromolecular sulfur-phosphorus composite crude oil distillation device, the general molecular formula of which is shown in Formula I, where n is a natural number between 0 and 8:
[0007]
[0008] Furthermore, the molecular formula of the high-temperature corrosion inhibitor for the macromolecular sulfur-phosphorus composite crude oil distillation unit is shown in Formula II:
[0009]
[0010] Another objective of this invention discloses a method for preparing a high-temperature corrosion inhibitor for a macromolecular sulfur-phosphorus composite crude oil distillation unit, comprising the following steps:
[0011] Step 1: At room temperature, add ethylenediamine dropwise to a mixture of phenylphosphonic dichloride and acetonitrile, and react for 2-4 hours;
[0012] Step 2: Add thiourea and heat to 100-120℃ to react for 1-2 hours;
[0013] Step 3: Add fatty acids and heat to 120-140℃ for 2-4 hours to prepare a high-temperature corrosion inhibitor for macromolecular sulfur-phosphorus composite crude oil distillation equipment.
[0014] Further, the molar ratio of phenylphosphonic dichloride, acetonitrile, ethyleneamine, thiourea, and fatty acid is 1-1.2:4-8:2-3:2-3:2-3. Preferably, the molar ratio of phenylphosphonic dichloride, acetonitrile, ethyleneamine, thiourea, and oleic acid is 1:5:2.2:2:2.
[0015] Furthermore, in step 2, acetonitrile is evaporated and recovered by condensation. Acetonitrile has a boiling point of 81.5℃, and the reaction temperature in step 2 is 100-120℃. During the reaction, the acetonitrile is evaporated, condensed, and recovered for reuse.
[0016] Furthermore, the ethylene amine is one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and polyethylenepolyamine.
[0017] Furthermore, the fatty acid is one or more of oleic acid, linoleic acid, tall oil acid, stearic acid, coconut oil acid, palmitic acid, and linolenic acid.
[0018] Furthermore, the reaction time described in step 1 is 3 hours.
[0019] Furthermore, the reaction time for heating to 100°C in step 2 is 1.5 hours.
[0020] Furthermore, the reaction time for raising the temperature to 140°C in step 3 is 3 hours.
[0021] Taking the preparation of a high-temperature corrosion inhibitor for a type II macromolecular sulfur-phosphorus composite crude oil distillation unit as an example, its synthesis route is as follows:
[0022]
[0023]
[0024] Another objective of this invention is to disclose the use of a high-temperature corrosion inhibitor for a macromolecular sulfur-phosphorus composite crude oil distillation unit in the field of high-temperature corrosion inhibition.
[0025] Furthermore, the macromolecular sulfur-phosphorus composite crude oil distillation unit high-temperature corrosion inhibitor is particularly suitable for corrosion inhibition in crude oil distillation units.
[0026] Furthermore, the high-temperature corrosion inhibitor for the macromolecular sulfur-phosphorus composite crude oil distillation unit is particularly suitable for the furnace tubes of the heating furnace, the diesel distillation pipeline of the atmospheric tower, the side pipeline of the vacuum tower, the atmospheric tower and the bottom of the vacuum tower in the atmospheric and vacuum tower processing units of oil refineries, where the temperature is in the range of 200-400℃ and is caused by chemical corrosion from petroleum acids.
[0027] Furthermore, the application temperature of the high-temperature corrosion inhibitor in the macromolecular sulfur-phosphorus composite crude oil distillation unit is 200-400℃.
[0028] Furthermore, the application method of the high-temperature corrosion inhibitor in the macromolecular sulfur-phosphorus composite crude oil distillation unit is as follows: the diluted corrosion inhibitor is continuously injected into the fluid before the corrosion site using a gear metering pump. The solvent used for dilution is one or more of diesel oil, solvent oil, and kerosene. The volume ratio of the high-temperature corrosion inhibitor to the solvent in the macromolecular sulfur-phosphorus composite crude oil distillation unit is 1:20-50.
[0029] Furthermore, the application rate of the high-temperature corrosion inhibitor in the macromolecular sulfur-phosphorus composite crude oil distillation unit is 80-100 μg / g, which can control the iron ion content of the fluid in the pipeline to be less than 3 μg / g.
[0030] The preparation method and application of the high-temperature corrosion inhibitor for macromolecular sulfur-phosphorus composite crude oil distillation equipment of the present invention have the following advantages compared with the prior art:
[0031] 1) The high-temperature corrosion inhibitor of the macromolecular sulfur-phosphorus composite crude oil distillation device of the present invention has a low phosphorus content (the phosphorus content of traditional corrosion inhibitors is 10%-18%, while the phosphorus content of the high-temperature corrosion inhibitor of the macromolecular sulfur-phosphorus composite crude oil distillation device of the present invention is only 2%-3%), contains sulfur element, is low in cost and easy to produce.
[0032] 2) The laboratory addition amount of the high-temperature corrosion inhibitor for the macromolecular sulfur-phosphorus composite crude oil distillation device of this invention is 150 μg / g, with a corrosion inhibition rate of over 90%. For industrial applications, the addition amount is 80-100 μg / g, with iron ion concentration less than 3 μg / g.
[0033] 3) The high-temperature corrosion inhibitor of the macromolecular sulfur-phosphorus composite crude oil distillation unit of the present invention has good application prospects and potential for large-scale industrial promotion in the field of crude oil distillation unit. Attached Figure Description
[0034] Figure 1 The infrared spectrum of the high-temperature corrosion inhibitor for the macromolecular sulfur-phosphorus composite crude oil distillation unit in Example 1 is shown. Detailed Implementation
[0035] The present invention will be further described below with reference to embodiments. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:
[0036] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.
[0037] In this specification, the range of values referred to as "value A to value B" refers to the range including the endpoint values A and B.
[0038] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.
[0039] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.
[0040] In this specification, the terms "optional" or "optional" are used to indicate the use or omission of certain substances, components, procedures, application conditions, etc.
[0041] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.
[0042] Unless otherwise specified, all reagents or instruments used in this instruction manual are commercially available products.
[0043] Unless otherwise specified, all percentages in this manual refer to mass percentages.
[0044] Example 1
[0045] This embodiment discloses a high-temperature corrosion inhibitor for a macromolecular sulfur-phosphorus composite crude oil distillation unit, the molecular formula of which is as follows:
[0046]
[0047] The preparation method of the high-temperature corrosion inhibitor for the macromolecular sulfur-phosphorus composite crude oil distillation unit includes the following steps:
[0048] 1 mol of phenylphosphonic dichloride and 5 mol of acetonitrile were added to a container, and 2.5 mol of diethylenetriamine was added dropwise at room temperature. The reaction was continued at room temperature for 3 hours. 2.5 mol of thiourea was then added, and the temperature was raised to 100℃, continuing the reaction for 1.5 hours. Acetonitrile was recovered by condensation. After the reaction, 2.5 mol of oleic acid was added, and the reaction was continued at 140℃ for 3 hours to obtain the final product: a high-temperature corrosion inhibitor for crude oil distillation equipment based on macromolecular sulfur and phosphorus compounds.
[0049] Figure 1 The infrared spectrum of the high-temperature corrosion inhibitor for the macromolecular sulfur-phosphorus composite crude oil distillation unit in Example 1 is visible at 2900 cm⁻¹. -1 The peak at 1600 cm⁻¹ represents the stretching vibration of the methylene group. -1 The peak at 1200 cm⁻¹ is the carbonyl vibration peak. -1 The peak at 1086 cm⁻¹ is the vibrational peak of the carbon nitride group. -1 The absorption peak at 1050 cm⁻¹ is the phosphorus-oxygen double bond absorption peak. -1 The peak at 1042 cm⁻¹ represents the carbon-sulfur double bond vibration. -1 The sharp peak is the vibrational peak of the nitrogen-phosphorus single bond, which indicates that the synthesized product is the target product.
[0050] The corrosion inhibition evaluation of the high-temperature corrosion inhibitor in the macromolecular sulfur-phosphorus composite crude oil distillation unit of this embodiment is as follows:
[0051] 1500 mL of white oil corrosive medium with an acid value adjusted to 7 mg KOH / g was placed in an autoclave. A 20# carbon steel test piece (Type III A3) was cleaned, weighed, and suspended in the autoclave, ensuring complete immersion in the experimental medium. The autoclave was heated to 280℃ and maintained for 6 hours at a constant stirring speed (200 rad / min) (nitrogen protection not required). The weight changes of the test pieces before and after the blank and additive experiments were examined. The corrosion inhibition rate was calculated based on the weight change of the test pieces. The results are expressed as a mass percentage, showing that the corrosion inhibition rate exceeds 90% when the amount of corrosion inhibitor added exceeds 150 μg / g.
[0052] Table 1 Corrosion Inhibition Rate
[0053] Serial Number Corrosion inhibitor dosage Corrosion inhibition rate 1 50μg / g 81.2％ 2 100μg / g 87.6％ 3 150μg / g 92.3％ 4 200μg / g 93.5％
[0054] Example 2
[0055] This embodiment discloses a high-temperature corrosion inhibitor for a macromolecular sulfur-phosphorus composite crude oil distillation unit, the molecular formula of which is as follows:
[0056]
[0057] The preparation method of the high-temperature corrosion inhibitor for the macromolecular sulfur-phosphorus composite crude oil distillation unit includes the following steps:
[0058] 1 mol of phenylphosphonic dichloride and 6 mol of acetonitrile were added to a container, and 3 mol of triethylenetetramine was added dropwise at room temperature. The reaction was continued at room temperature for 4 hours. 3 mol of thiourea was then added, and the temperature was raised to 100℃, with the reaction continuing for 2 hours. Acetonitrile was recovered by condensation. After the reaction, 3 mol of linoleic acid was added, and the reaction was carried out at 140℃ for 4 hours to obtain the final product: a high-temperature corrosion inhibitor for crude oil distillation equipment consisting of macromolecular sulfur and phosphorus compounds. Infrared spectroscopy analysis confirmed the successful preparation of the target product.
[0059] The corrosion inhibition evaluation of the high-temperature corrosion inhibitor in the macromolecular sulfur-phosphorus composite crude oil distillation unit of this embodiment is as follows:
[0060] 1500 mL of white oil corrosive medium with an acid value adjusted to 7 mg KOH / g was placed in an autoclave. A 20# carbon steel test piece (Type III A3) was cleaned, weighed, and suspended in the autoclave, ensuring complete immersion in the experimental medium. The autoclave was heated to 280℃ and maintained for 6 hours at a constant stirring speed (200 rad / min) (nitrogen protection not required). The weight changes of the test pieces before and after the blank and additive experiments were examined. The corrosion inhibition rate was calculated based on the weight change of the test pieces. The results are expressed as a mass percentage, showing that the corrosion inhibition rate exceeds 90% when the amount of corrosion inhibitor added exceeds 150 μg / g.
[0061] Table 2 Corrosion Inhibition Rate
[0062] Serial Number Corrosion inhibitor dosage Corrosion inhibition rate 1 50μg / g 80.3％ 2 100μg / g 86.4％ 3 150μg / g 91.8％ 4 200μg / g 92.4％
[0063] Example 3
[0064] This embodiment discloses a high-temperature corrosion inhibitor for a macromolecular sulfur-phosphorus composite crude oil distillation unit, the molecular formula of which is as follows:
[0065]
[0066] The preparation method of the high-temperature corrosion inhibitor for the macromolecular sulfur-phosphorus composite crude oil distillation unit includes the following steps:
[0067] 1.2 mol of phenylphosphonic dichloride and 6 mol of acetonitrile were added to a container, and 3 mol of tetraethylenepentamine was added dropwise at room temperature. The reaction was carried out for 4 hours at room temperature. Then, 3 mol of thiourea was added, and the temperature was raised to 100℃, and the reaction was continued for 2 hours. Acetonitrile needed to be recovered by condensation. After the reaction, 2 mol of tall oil acid was added, and the reaction was carried out at 140℃ for 4 hours to obtain the final product: a high-temperature corrosion inhibitor for crude oil distillation equipment consisting of macromolecular sulfur and phosphorus compounds. Infrared spectroscopy analysis confirmed the preparation of the target product.
[0068] The corrosion inhibition evaluation of the high-temperature corrosion inhibitor in the macromolecular sulfur-phosphorus composite crude oil distillation unit of this embodiment is as follows:
[0069] 1500 mL of white oil corrosive medium with an acid value adjusted to 7 mg KOH / g was placed in an autoclave. A 20# carbon steel test piece (Type III A3) was cleaned, weighed, and suspended in the autoclave, ensuring complete immersion in the experimental medium. The autoclave was heated to 280℃ and maintained for 6 hours at a constant stirring speed (200 rad / min) (nitrogen protection not required). The weight changes of the test pieces before and after the blank and additive experiments were examined. The corrosion inhibition rate was calculated based on the weight change of the test pieces. The results are expressed as a mass percentage, showing that the corrosion inhibition rate exceeds 90% when the amount of corrosion inhibitor added exceeds 150 μg / g.
[0070] Table 2 Corrosion Inhibition Rate
[0071] Serial Number Corrosion inhibitor dosage Corrosion inhibition rate 1 50μg / g 78.6％ 2 100μg / g 85.3％ 3 150μg / g 90.2％ 4 200μg / g 91.9％
[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A macromolecular sulfur-phosphorus complex high-temperature corrosion inhibitor for crude oil distillation units, characterized in that, Its numerator is given by formula I, where n is a natural number between 0 and 8: ； Formula I.
2. The macromolecular sulfur-phosphorus complex crude oil distillation unit high temperature corrosion inhibitor of claim 1, wherein, Its molecular formula is shown in Formula II: ； Formula II.
3. A method for preparing the high-temperature corrosion inhibitor for a macromolecular sulfur-phosphorus composite crude oil distillation unit as described in claim 1 or 2, characterized in that, Includes the following steps: Step 1: At room temperature, add ethylenediamine dropwise to a mixture of phenylphosphonic dichloride and acetonitrile, and react for 2-4 hours; Step 2: Add thiourea and heat to 100-120℃ for 1-2 hours; Step 3: Add oleic acid and heat to 120-140℃ for 2-4 hours to prepare a high-temperature corrosion inhibitor for macromolecular sulfur-phosphorus composite crude oil distillation equipment.
4. The preparation method of the high-temperature corrosion inhibitor for the macromolecular sulfur-phosphorus composite crude oil distillation unit according to claim 3, characterized in that, The molar ratio of phenylphosphonodichloro, acetonitrile, ethyleneamine, thiourea and oleic acid is 1-1.2:4-8:2-3:2-3:2-3.
5. The preparation method of the high-temperature corrosion inhibitor for the macromolecular sulfur-phosphorus composite crude oil distillation unit according to claim 3, characterized in that, In step 2, the acetonitrile is evaporated and then condensed and recovered.
6. The preparation method of the high-temperature corrosion inhibitor for the macromolecular sulfur-phosphorus composite crude oil distillation unit according to claim 3, characterized in that, The ethylene amine is one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and polyethylenepolyamine.
7. The preparation method of the high-temperature corrosion inhibitor for the macromolecular sulfur-phosphorus composite crude oil distillation unit according to claim 3, characterized in that, The reaction time described in step 1 is 3 hours; And / or, the reaction time for raising the temperature to 100°C in step 2 is 1.5 hours; And / or, the reaction time at 140°C in step 3 is 3 hours.
8. The use of the high-temperature corrosion inhibitor of the macromolecular sulfur-phosphorus composite crude oil distillation unit as described in claim 1 or 2 in the field of high-temperature corrosion inhibition.
9. The use according to claim 8, characterized in that, The application temperature of the high-temperature corrosion inhibitor in the macromolecular sulfur-phosphorus composite crude oil distillation unit is 200-400℃. And / or, the method of applying the high-temperature corrosion inhibitor of the macromolecular sulfur-phosphorus composite crude oil distillation unit is as follows: the diluted corrosion inhibitor is continuously injected into the fluid before the corrosion site using a gear metering pump; And / or, the application rate of the high-temperature corrosion inhibitor in the macromolecular sulfur-phosphorus composite crude oil distillation unit is 80-100 μg / g.