Composite corrosion inhibitor as well as preparation method and application thereof

Abstract

The invention relates to the technical field of oil exploitation, and discloses a composite corrosion inhibitor and a preparation method and application thereof. The method comprises the following steps: (1) in the presence of ethanol and under the condition that the pH value is 2-3, enabling trimethylolpropane-tri (3-aziridinyl propionate) and octadecyl aminopropionic acid-sodium salt to be in contact to carry out mixed reaction, so as to obtain a mixed solution; and (2) under the condition that the pH value is 9-10, the mixed solution is in contact with sodium chloroethanesulfonate for a reflux reaction, and the composite corrosion inhibitor is obtained, wherein the molar ratio of the trimethylolpropane-tri (3-aziridinyl propionate) to the sodium octadecyl aminopropionate to the sodium chloroethanesulfonate is 1: (2.5 to 3.5): (8 to 11). The composite corrosion inhibitor prepared by the method for preparing the composite corrosion inhibitor provided by the invention has the advantages of small dosage and good corrosion inhibition effect, does not contain phosphorus in molecules, does not generate secondary pollution, and is environment-friendly.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum extraction, and in particular to a composite corrosion inhibitor and a preparation method and application thereof. Background Art

[0002] With the substantial increase in oil demand, how to improve oil recovery is the focus of the current major oil field petroleum technology practitioners. Water injection for oil recovery is widely used in oil production due to its simple operation and low cost. Oilfield wastewater treatment and reinjection water quality are very important, and corrosion is one of the most serious problems encountered in the process of oilfield wastewater treatment and reinjection. Oilfield oily wastewater has complex water quality, high harmful components, high mineralization, and contains dissolved salts, H2S, CO2, sulfate-reducing bacteria and dissolved oxygen. After being reinjected into the formation, it will cause serious corrosion to the metal equipment and pipelines in the water injection system. Adding corrosion inhibitors can effectively avoid this problem.

[0003] Corrosion inhibitors can be adsorbed on the metal surface to form a stable protective film, preventing corrosive media from diffusing to the metal surface, thereby achieving the purpose of slowing down corrosion.

[0004] Commonly used corrosion inhibitors in oil fields include amines, cyclic amines, amides, amide carboxylic acids and their derivatives, imidazolines and their derivatives, etc. There are a variety of corrosion inhibitors in the prior art, but they generally have the disadvantages of large dosage, low corrosion inhibition efficiency, and large side effects.

[0005] For example, CN108018559A discloses a compound oilfield corrosion inhibitor and its preparation method, including liquid A and liquid B with a volume ratio of 1:3, wherein the active ingredient of liquid A is mainly aromatic ketone Mannich base, and the active ingredient of liquid B is mainly oleic acid imidazoline; through the synergistic effect between liquid A and liquid B, a downhole corrosion inhibitor with high temperature resistance, oxygen resistance and acid resistance is prepared. However, the raw materials in the preparation process of this corrosion inhibitor are various, the product is highly toxic, the preparation time is long, and high temperature resistance and strong acid and alkali equipment such as reactors are required, the operating cost is high, and the corrosion inhibition efficiency is only 80%.

[0006] For another example, CN104817193A discloses a water treatment corrosion inhibitor and a preparation method thereof, wherein the water treatment corrosion inhibitor is an imidazoline quaternary ammonium salt, and the method comprises reacting an imidazoline compound with a quaternizing agent to generate an imidazoline quaternary ammonium salt, wherein the imidazoline compound is synthesized by reacting an organic carboxylic acid with an organic polyether polyamine, and the quaternizing agent is a combination of one or more of dimethyl carbonate, diethyl carbonate, and ethylene carbonate. This method has low toxicity during the synthesis process and is easy to operate, but in order to maintain excellent sustained-release ability, a dosage of 5 g / L of the agent needs to be added, which is too large and the cost is too high. At the same time, the maximum corrosion inhibition efficiency is only 95.6%. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects of the corrosion inhibitor in the prior art, such as large dosage and low corrosion inhibition efficiency.

[0008] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a composite corrosion inhibitor, the method comprising:

[0009] (1) in the presence of ethanol, at a pH of 2-3, contacting trimethylolpropane-tris(3-aziridinyl propionate) and octadecylaminopropionic acid monosodium salt to carry out a mixing reaction to obtain a mixed solution;

[0010] (2) contacting the mixed solution with sodium chloroethylsulfonate at a pH value of 9-10 to perform a reflux reaction to obtain the composite corrosion inhibitor;

[0011] The molar ratio of the trimethylolpropane-tris(3-aziridinyl propionate), the sodium octadecylaminopropionic acid salt and the sodium chloroethyl sulfonate is 1:2.5-3.5:8-11.

[0012] Preferably, the molar ratio of the trimethylolpropane-tris(3-aziridinyl propionate), the sodium octadecylaminopropionic acid salt and the sodium chloroethylsulfonate is 1:2.8-3.2:9-11.

[0013] Preferably, in step (1), the weight ratio of the trimethylolpropane-tris(3-aziridinyl propionate) to the ethanol is 1:40-50.

[0014] Preferably, in step (1), the conditions of the mixed reaction include: reaction temperature of 50-60° C., and reaction time of 4-8 h.

[0015] Preferably, in step (2), the conditions for the reflux reaction include: a stirring speed of 40-120 rpm, and a reaction time of 24-72 h.

[0016] Preferably, the method further comprises: in step (2), post-treating the product I obtained by the reflux reaction to obtain the composite corrosion inhibitor.

[0017] Preferably, the post-treatment operation comprises vacuum distillation, dissolution, filtration and drying performed in sequence.

[0018] Preferably, the conditions of the reduced pressure distillation are controlled so that the content of ethanol in the product II after the reduced pressure distillation is no higher than 9.7 wt %.

[0019] The second aspect of the present invention provides a composite corrosion inhibitor prepared by the method described in the first aspect.

[0020] The third aspect of the present invention provides the use of the composite corrosion inhibitor described in the second aspect in CO2 oil recovery.

[0021] Through the above technical solution, the present invention has at least the following advantages:

[0022] The composite corrosion inhibitor prepared by the method for preparing the composite corrosion inhibitor provided by the present invention has the advantages of small dosage and good corrosion inhibition effect; wherein, when the concentration is 3 mg / L, the corrosion inhibition rate reaches more than 96%; when the concentration is 5 mg / L, the corrosion inhibition rate reaches more than 97%.

[0023] In addition, the composite corrosion inhibitor provided by the present invention does not contain phosphorus in its molecules, will not generate secondary pollution, and is environmentally friendly. DETAILED DESCRIPTION

[0024] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0025] In the present invention, the chemical formula of trimethylolpropane-tris(3-aziridinyl propionate) is C 21 H 35 N3O6, the structural formula is shown in formula (a); the chemical formula of the sodium salt of octadecylaminopropionic acid is C 21 H 42 NNaO2, with a structural formula shown in formula (b); the chemical formula of the sodium chloroethylsulfonate is C2H6ClNaO4S, with a structural formula shown in formula (c);

[0026]

[0027] As mentioned above, the first aspect of the present invention provides a method for preparing a composite corrosion inhibitor, the method comprising:

[0028] (1) in the presence of ethanol, at a pH of 2-3, contacting trimethylolpropane-tris(3-aziridinyl propionate) and octadecylaminopropionic acid monosodium salt to carry out a mixing reaction to obtain a mixed solution;

[0029] (2) contacting the mixed solution with sodium chloroethylsulfonate at a pH value of 9-10 to perform a reflux reaction to obtain the composite corrosion inhibitor;

[0030] The molar ratio of the trimethylolpropane-tris(3-aziridinyl propionate), the sodium octadecylaminopropionic acid salt and the sodium chloroethyl sulfonate is 1:2.5-3.5:8-11.

[0031] The inventors of the present invention found in the course of research that under conditions such as a specific pH value, trimethylolpropane-tris (3-aziridinyl propionate), sodium octadecylaminopropionic acid and sodium chloroethylsulfonate are used as raw materials to prepare a composite corrosion inhibitor, and the obtained product has the advantages of small dosage and good corrosion inhibition effect. The possible mechanism of action is speculated as follows: the quaternary ammonium salt has a positive charge and high electrical property, and can be adsorbed on the metal surface, preventing hydrogen ions in petroleum (oil well) produced water from approaching the metal surface, and hindering electrons in the metal from being captured by hydrogen ions, thereby protecting the metal from corrosion; carboxylates and sulfonates are classic slow-release groups, which work synergistically with octadecyl groups to form a chelate film on the metal surface to protect the metal; octadecyl groups and ester groups have a hydrophobic effect, and can form a layer of hydrophobic barrier on the metal surface, so that the corrosive liquid cannot approach the metal, thereby further strengthening the corrosion inhibition effect; there are multiple adsorption centers in the composite corrosion inhibitor molecule, such as N, O, S atoms, which can provide lone pairs of electrons, improve the oxidation resistance of the metal, and prevent the occurrence of corrosion.

[0032] Preferably, the synthesis route of the composite corrosion inhibitor provided by the present invention is as follows:

[0033]

[0034]

[0035] Preferably, the molar ratio of the trimethylolpropane-tris(3-aziridinyl propionate) to the sodium salt of octadecylaminopropionic acid to the sodium chloroethylsulfonate is 1:2.8-3.2:9-11.

[0036] Preferably, in step (1), an inorganic acid is used to adjust the pH value to 2-3.

[0037] More preferably, the inorganic acid is hydrochloric acid.

[0038] Preferably, in step (1), the weight ratio of the trimethylolpropane-tris(3-aziridinyl propionate) to the ethanol is 1:40-50.

[0039] Preferably, in step (1), the conditions of the mixed reaction include: reaction temperature of 50-60° C., and reaction time of 4-8 h.

[0040] Preferably, in step (2), an inorganic base is used to adjust the pH value to 9-10.

[0041] More preferably, the inorganic base is sodium hydroxide.

[0042] Preferably, in step (2), the conditions for the reflux reaction include: a stirring speed of 40-120 rpm, and a reaction time of 24-72 h.

[0043] Preferably, the method further comprises: in step (2), post-treating the product I obtained by the reflux reaction to obtain the composite corrosion inhibitor.

[0044] Preferably, the post-treatment operation comprises vacuum distillation, dissolution, filtration and drying performed in sequence.

[0045] Preferably, the conditions of the reduced pressure distillation are controlled so that the content of ethanol in the product II after the reduced pressure distillation is no higher than 9.7 wt %.

[0046] Preferably, the dissolving temperature is 70-90°C.

[0047] Preferably, the solvent used for the dissolution is water.

[0048] More preferably, during the dissolution process, the weight ratio of the trimethylolpropane-tris(3-aziridinyl propionate) to the water is 1:50-60.

[0049] According to a preferred specific embodiment, before the filtration, the dissolved product ⅢⅠis first cooled and crystallized at a pH value of 6-8; more preferably, hydrochloric acid is used to adjust the pH value to 6-8.

[0050] More preferably, the cooling crystallization makes the temperature of product III below 10°C.

[0051] The present invention has no particular limitation on the filtering and drying methods. For example, the filtering method may be suction filtration, and the drying method may be baking.

[0052] As mentioned above, the second aspect of the present invention provides a composite corrosion inhibitor prepared by the method described in the first aspect.

[0053] Preferably, the structural formula of the composite corrosion inhibitor is shown in formula (d);

[0054]

[0055] As mentioned above, the third aspect of the present invention provides the use of the composite corrosion inhibitor described in the second aspect in CO2 flooding.

[0056] The present invention will be described in detail below through examples.

[0057] In the following examples, unless otherwise specified, the instruments, reagents, materials, etc. involved are all conventional instruments, reagents, materials, etc., which can be obtained through conventional commercial channels. In particular, unless otherwise specified, the reagents used are all commercially available analytically pure products.

[0058] Among them, the following compounds were purchased from Shanghai Jizhi Biochemical Technology Co., Ltd.;

[0059] Trimethylolpropane-tris(3-aziridinyl propionate): CAS number is 52234-82-9.

[0060] Octadecylaminopropionic acid monosodium salt: CAS number is 56862-02-3.

[0061] Dodecyl primary amine: CAS number is 124-22-1, linear molecular formula is CH3(CH2) 11 NH2.

[0062] Octadecyl primary amine: CAS number is 124-30-1, linear molecular formula is CH3(CH2) 17 NH2.

[0063] 5-aminoisophthalic acid: CAS number is 99-31-0, structural formula is

[0064] In the following examples, hydrochloric acid was used to adjust the pH of the mixed reaction; sodium hydroxide was used to adjust the pH of the reflux reaction; and hydrochloric acid was used to adjust the pH of the cooling crystallization.

[0065] Example 1

[0066] (1) in the presence of ethanol, contacting trimethylolpropane-tris(3-aziridinyl propionate) and octadecylaminopropionic acid monosodium salt to carry out a mixing reaction to obtain a mixed solution;

[0067] (2) contacting the mixed solution with sodium chloroethylsulfonate to perform a reflux reaction, and performing reduced pressure distillation on the product I obtained by the reflux reaction to obtain product Ⅰ;

[0068] The product ⅠⅠ was heated and dissolved with deionized water (temperature: 75°C, time: 25 min) to obtain the product ⅠⅠⅠ;

[0069] Under the condition of pH 7, the dissolved product ⅢⅠⅠ is cooled and crystallized (so that the temperature of product ⅢⅠⅠ is below 10°C), solid is precipitated, and then filtered (suction filtration) and dried (drying) to obtain a composite corrosion inhibitor.

[0070] The material ratio and reaction conditions of this embodiment are shown in Table 1.

[0071] Examples 2 to 4 are all prepared using the same preparation method as Example 1, except that the material ratios and reaction conditions are different, as shown in Table 1.

[0072] Table 1 (C 21 H 35 The dosage of N3O6 is 10mmol)

[0073]

[0074]

[0075] Example 5

[0076] This embodiment is carried out in a similar manner to that of embodiment 1, except that the C 21 H 35 The dosage of N3O6 remains unchanged, and the C 21 H 35 N3O6、C 21 H 42 The molar ratio of NNaO2 and C2H6ClNaO4S is 1:2.5:8 to obtain a composite corrosion inhibitor.

[0077] Example 6

[0078] This embodiment is carried out in a similar manner to that of embodiment 1, except that the C 21 H 35 The dosage of N3O6 remains unchanged, and the C 21 H 35 N3O6、C 21 H 42 The molar ratio of NNaO2 and C2H6ClNaO4S is 1:3.5:8.5, and a composite corrosion inhibitor is obtained.

[0079] Example 7

[0080] This embodiment is carried out in a similar manner to that of embodiment 1, except that the C 21 H 35 The dosage of N3O6 remains unchanged, and the C 21 H 35 N3O6、C 21 H 42 The molar ratio of NNaO2 and C2H6ClNaO4S is 1:2.7:9.0, and a composite corrosion inhibitor is obtained.

[0081] Comparative Example 1

[0082] This comparative example was carried out in a similar manner to Example 1, except that 21 H35 The dosage of N3O6 remains unchanged, and the C 21 H 35 N3O6、C 21 H 42 The molar ratio of NNaO2 and C2H6ClNaO4S is 1:4:6, and a composite corrosion inhibitor is obtained.

[0083] Comparative Example 2

[0084] This comparative example was carried out in a similar manner to Example 1, except that the sodium salt of octadecylaminopropionic acid in this comparative example was replaced with an equal molar amount of dodecyl primary amine, and the pH value of the mixed reaction was adjusted to 5, thereby obtaining a composite corrosion inhibitor.

[0085] Comparative Example 3

[0086] This comparative example is carried out in a similar manner to Example 1, except that the sodium salt of octadecylaminopropionic acid in this comparative example is replaced with an equal molar amount of octadecyl primary amine, and the pH value of the mixed reaction is adjusted to 1, thereby obtaining a composite corrosion inhibitor.

[0087] Comparative Example 4

[0088] This comparative example is carried out in a similar manner to Example 1, except that the sodium salt of octadecylaminopropionic acid in this comparative example is replaced with an equal molar amount of 5-aminoisophthalic acid to obtain a composite corrosion inhibitor.

[0089] Test Case

[0090] The corrosion inhibition effect of the composite corrosion inhibitor obtained in the example was tested. The test method referred to GB / T 18175-2014 "Determination of Corrosion Inhibition Performance of Water Treatment Agents - Rotating Hanging Plate Method". The test water was produced water from a CO2 flooding block in Shengli Oilfield, and the dosing concentrations were 3 mg / L and 5 mg / L, respectively. At the same time, the above test results were compared with the CO2 oil well corrosion inhibitor of Puyang Wanliang Petroleum Technology Development Co., Ltd. (a brown uniform liquid, easily soluble in water, the main components of which are imidazoline derivatives synthesized from palmitic acid, diethylenetriamine, maleic anhydride, thiourea, pyridine quaternary ammonium salts and non-polar surfactants). The evaluation results are shown in Table 2.

[0091] The calculation formula of the corrosion rate PE of the corrosion inhibitor is: PE = 100 × (W1-W2) / W1 × 100%;

[0092] Wherein, W1 is the weight loss of metal without adding corrosion inhibitor, and W2 is the weight loss after adding corrosion inhibitor.

[0093] The calculation formula of the corrosion inhibition rate η of the corrosion inhibitor is: η=(R0-R1) / R0×100%;

[0094] Among them, R0 represents the corrosion rate without adding corrosion inhibitor, and R1 represents the corrosion rate after adding corrosion inhibitor.

[0095] Table 2

[0096]

[0097] The above results show that the corrosion inhibition rate of the corrosion inhibitor provided by the present invention reaches more than 96% when the use concentration is 3 mg / L, and the highest is 96.97%; while the corrosion inhibition rate of the corrosion inhibitor of Wanliang Petroleum Company is only 88.16%, which is significantly lower than that of the present invention;

[0098] The corrosion inhibition rate of the corrosion inhibitor of the present invention reaches more than 97% when the use concentration is 5 mg / L, and the highest reaches 97.68%; while the corrosion inhibition rate of the corrosion inhibitor of Wanliang Petroleum Company is only 92.63%, which is significantly lower than that of the present invention.

[0099] Furthermore, the composite corrosion inhibitor provided by the present invention does not contain phosphorus in its molecules, will not generate secondary pollution, and is environmentally friendly.

[0100] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a composite corrosion inhibitor, characterized in that: The method includes: (1) in the presence of ethanol, at a pH of 2-3, contacting trimethylolpropane-tris(3-aziridinyl propionate) and octadecylaminopropionic acid monosodium salt to carry out a mixing reaction to obtain a mixed solution; (2) contacting the mixed solution with sodium chloroethylsulfonate at a pH value of 9-10 to perform a reflux reaction to obtain the composite corrosion inhibitor; The molar ratio of the trimethylolpropane-tris(3-aziridinyl propionate), the sodium octadecylaminopropionic acid salt and the sodium chloroethyl sulfonate is 1:2.5-3.5:8-11.

2. The method according to claim 1, characterized in that The molar ratio of the trimethylolpropane-tris(3-aziridinyl propionate), the sodium octadecylaminopropionic acid salt and the sodium chloroethylsulfonate is 1:2.8-3.2:9-11.

3. The method according to claim 1, characterized in that In step (1), the weight ratio of the trimethylolpropane-tris(3-aziridinyl propionate) to the ethanol is 1:40-50.

4. The method according to any one of claims 1 to 3, characterized in that: In step (1), the conditions of the mixed reaction include: reaction temperature of 50-60° C., and reaction time of 4-8 h.

5. The method according to any one of claims 1 to 3, characterized in that: In step (2), the conditions for the reflux reaction include: a stirring speed of 40-120 rpm and a reaction time of 24-72 h.

6. The method according to any one of claims 1 to 3, characterized in that: The method further comprises: in step (2), post-treating the product I obtained by the reflux reaction to obtain the composite corrosion inhibitor.

7. The method according to claim 6, characterized in that The post-treatment operation includes vacuum distillation, dissolution, filtration and drying performed in sequence.

8. The method according to claim 7, characterized in that The conditions of the reduced pressure distillation are controlled so that the content of ethanol in the product Ⅱ after the reduced pressure distillation is no higher than 9.7wt%.

9. The composite corrosion inhibitor prepared by the method according to any one of claims 1 to 8.

10. Use of the composite corrosion inhibitor according to claim 9 in CO2 flooding.

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