A polymerization inhibitor for inhibiting the polymerization of olefins in petroleum pyrolysis C5 fraction

Abstract

The present invention relates to an inhibitor for suppressing the polymerization of olefins in petroleum pyrolysis C5 fraction, and particularly to a preparation method of an inhibitor for suppressing the polymerization of olefins in petroleum pyrolysis C5 fraction. The present invention utilizes the synergistic effect after compounding 1-ethyl-3-methylimidazolium diethyl phosphate with tert-butylcatechol and N,N-diethylhydroxylamine to improve the inhibition effect; in addition, No. 180 solvent oil and mesitylene are used as solvents to dissolve tert-butylcatechol and N,N-diethylhydroxylamine respectively, and cavitation is carried out by ultrasonic during the dissolution process to promote dissolution and mixing. Under the action of ultrasonic, the above two solutions are ultrasonically and uniformly mixed with the ionic liquid 1-ethyl-3-methylimidazolium diethyl phosphate to form an inhibitor, further improving the inhibition effect.

Description

Technical Field

[0001] The present invention relates to a polymerization inhibitor for inhibiting the polymerization of olefins in petroleum pyrolysis C5 fraction, and particularly to a preparation method of a polymerization inhibitor for inhibiting the polymerization of olefins in petroleum pyrolysis C5 fraction. Background Art

[0002] In the process of producing ethylene by petroleum pyrolysis, a considerable amount of C5 fraction is by-produced. The C5 fraction contains about 40-60% of diolefins such as isoprene, cyclopentadiene and piperylene. These diolefins have active chemical properties and are important raw materials for many fine chemical products. Therefore, the separation and utilization of C5 fraction is very meaningful for improving the economic benefits of ethylene plants and comprehensively utilizing petroleum resources.

[0003] In the production process of separating pyrolysis C5, there are a large number of unsaturated diolefins, and the raw materials inevitably contain impurities such as water, oxygen and metal ions. Under the operating temperature conditions, polymerization reactions are extremely likely to occur, which become the main factors affecting the production cycle of the device. Production practice shows that the use of polymerization inhibitors can effectively prevent and slow down the polymerization and fouling of such substances prone to polymerization during the production process, and extend the operation cycle of the device. Therefore, people have studied the polymerization inhibitors used in pyrolysis C5 separation devices.

[0004] Using tert-butylcatechol and diethylhydroxylamine dissolved in a solvent as a polymerization inhibitor, such as Chinese Patent CN100348561C, the total content of the polymerization-inhibiting components of the polymerization inhibitor is 30-40 wt%, the dosage of the polymerization inhibitor is large, and the polymerization-inhibiting effect is poor at the same time.

[0005] Therefore, at present, the commonly used polymerization inhibitors for inhibiting the self-polymerization or copolymerization of C5 diolefins include free radical type, phenol type (quinone type), amine type (hydroxylamine type), nitro compounds such as o-nitrophenol, nitrobenzene, etc. However, there are still problems with poor polymerization-inhibiting effects. Summary of the Invention

[0006] The object of the present invention is to provide a polymerization inhibitor for inhibiting the polymerization of olefins in petroleum pyrolysis C5 fraction. The present invention utilizes the synergistic effect after compounding 1-ethyl-3-methylimidazolium diethyl phosphate with tert-butylcatechol and N,N-diethylhydroxylamine to improve the polymerization-inhibiting effect; in addition, No. 180 solvent oil and mesitylene are used as solvents to dissolve tert-butylcatechol and N,N-diethylhydroxylamine respectively, and cavitation is carried out by ultrasonic waves during the dissolution process to promote dissolution and mixing. Under the action of ultrasonic waves, the above two solutions are ultrasonically and uniformly mixed with the ionic liquid 1-ethyl-3-methylimidazolium diethyl phosphate to form a polymerization inhibitor, further improving the polymerization-inhibiting effect.

[0007] The technical solution for the present invention to achieve the above problems is as follows:

[0008] In a first aspect, the present invention provides a polymerization inhibitor for inhibiting the polymerization of olefins in cracked C5 fraction of petroleum.

[0009] In a second aspect, the present invention provides a preparation method of the above-mentioned polymerization inhibitor for inhibiting the polymerization of olefins in cracked C5 fraction of petroleum.

[0010] In a third aspect, the present invention provides a method for inhibiting the polymerization of olefins in cracked C5 fraction of petroleum by using the above-mentioned polymerization inhibitor.

[0011] Regarding the first aspect, the present invention provides a polymerization inhibitor for inhibiting the polymerization of olefins in cracked C5 fraction of petroleum. The polymerization inhibitor is composed of component 1, component 2, component 3, solvent 1 and solvent 2. Component 1 is tert-butylcatechol, component 2 is N,N-diethylhydroxylamine, component 3 is 1-ethyl-3-methylimidazolium diethyl phosphate, solvent 1 is solvent oil No. 180, and solvent 2 is mesitylene, toluene, xylene, naphthalene. The weight percentage of component 1 in the polymerization inhibitor is 11-16 wt%, the weight percentage of component 2 is 6-9 wt%, the weight percentage of component 3 is 3-5 wt%, the weight percentage of solvent 1 is 60-68 wt%, and the weight percentage of solvent 2 is 7-15 wt%. The sum of the weight percentages of component 1, component 2 and component 3 is below 25 wt%.

[0012] Furthermore, the specific preparation steps of the polymerization inhibitor are as follows: Step 1, weigh each component and solvent according to the weight percentages of the polymerization inhibitor; Step 2, add component 1 to solvent 1 and perform ultrasonic cavitation to obtain solution A; Step 3, add component 2 to solvent 2 and perform ultrasonic cavitation to obtain solution B; Step 4, mix solution A, solution B and component 3, and perform ultrasonic cavitation to obtain the polymerization inhibitor.

[0013] Furthermore, the solvent 2 is mesitylene.

[0014] Furthermore, the weight percentage of component 1 in the polymerization inhibitor is 14 wt%, the weight percentage of component 2 is 7 wt%, the weight percentage of component 3 is 4 wt%, the weight percentage of solvent 1 is 65 wt%, and the weight percentage of solvent 2 is 10 wt%.

[0015] Regarding the second aspect, the present invention provides a method for preparing the above-mentioned polymerization inhibitor for inhibiting the polymerization of olefins in petroleum pyrolysis C5 fraction. The polymerization inhibitor is composed of component 1, component 2, component 3, solvent 1 and solvent 2. Component 1 is tert-butylcatechol, component 2 is N,N-diethylhydroxylamine, component 3 is 1-ethyl-3-methylimidazolium diethyl phosphate, solvent 1 is No. 180 solvent oil, and solvent 2 is mesitylene, toluene, xylene, naphthalene. The weight percentage of component 1 in the polymerization inhibitor is 11-16 wt%, the weight percentage of component 2 is 6-9 wt%, the weight percentage of component 3 is 3-5 wt%, the weight percentage of solvent 1 is 60-68 wt%, and the weight percentage of solvent 2 is 7-15 wt%. The sum of the weight percentages of component 1, component 2 and component 3 is below 25 wt%. The specific preparation method of the polymerization inhibitor is as follows: Step 1, weigh each component and solvent according to the weight percentage of the polymerization inhibitor; Step 2, add component 1 to solvent 1 and carry out ultrasonic cavitation to obtain solution A; Step 3, add component 2 to solvent 2 and carry out ultrasonic cavitation to obtain solution B; Step 4, mix solution A, solution B and component 3, and carry out ultrasonic cavitation to obtain the polymerization inhibitor.

[0016] Further, the solvent 2 is mesitylene.

[0017] Further, the weight percentage of component 1 in the polymerization inhibitor is 14 wt%, the weight percentage of component 2 is 7 wt%, the weight percentage of component 3 is 4 wt%, the weight percentage of solvent 1 is 65 wt%, and the weight percentage of solvent 2 is 10 wt%.

[0018] Further, the ultrasonic cavitation time in Step 2 is 15-30 min, the ultrasonic cavitation time in Step 3 is 5-20 min, and the ultrasonic cavitation time in Step 4 is 15-40 min.

[0019] Regarding the third aspect, the present invention provides a method for inhibiting the polymerization of olefins in petroleum pyrolysis C5 fraction by using the above-mentioned polymerization inhibitor. The method includes adding the above-mentioned polymerization inhibitor to the C5 fraction material and maintaining a certain amount of the polymerization inhibitor in the C5 fraction material. The amount of the polymerization inhibitor maintained in the C5 fraction material is 50-400 ppm based on the total amount of component 1, component 2 and component 3.

[0020] Further, the amount of the polymerization inhibitor maintained in the C5 fraction material is 100 ppm based on the total amount of component 1, component 2 and component 3, and the polymer content is below 0.39 wt%.

[0021] The beneficial effects of the present invention:

[0022] (1) It was surprisingly found through experiments that after compounding 1-ethyl-3-methylimidazolium diethyl phosphate with tert-butylcatechol and N,N-diethylhydroxylamine, the three of them have an obvious synergistic effect. The sum of the weight percentages of 1-ethyl-3-methylimidazolium diethyl phosphate, tert-butylcatechol, and N,N-diethylhydroxylamine in the inhibitor is below 25 wt%, the use of the inhibitor is significantly reduced, and the inhibition effect is good. 1-ethyl-3-methylimidazolium diethyl phosphate plays multiple roles. It is an ionic liquid type inhibitor that can synergistically inhibit polymerization with tert-butylcatechol. It can also be used as an organic solvent and, together with solvent oil No. 180 and xylene, as a compounding solvent. With its phosphate ester structure, it can also have a good synergistic effect with N,N-diethylhydroxylamine, resulting in a better inhibition effect, improving the inhibition effect and ensuring that the polymer content is below 0.4 wt%. However, the compounding of any two of 1-ethyl-3-methylimidazolium diethyl phosphate, tert-butylcatechol, and N,N-diethylhydroxylamine (when the polymer content is above 2 wt%) is significantly worse than the inhibition effect achieved by the compounding of the three. Moreover, when removing solvent oil No. 180, the inhibition effect also deteriorates, and the polymer content reaches 0.86 wt%.

[0023] (2) In the preparation method of the present invention, solvent oil No. 180 and mesitylene are used as solvents to dissolve tert-butylcatechol and N,N-diethylhydroxylamine respectively. During the dissolution process, ultrasonic cavitation is used to promote dissolution and mixing. Under the action of ultrasonic waves, the above two solutions are ultrasonically and uniformly mixed with the ionic liquid to form an inhibitor, and its inhibition effect is better, with the polymer content below 0.4 wt%. When mixing under the action of mechanical forces such as magnetic stirring, the mixing effect is not as good as ultrasonic cavitation, resulting in a slightly worse inhibition effect than that of ultrasonic cavitation. Moreover, when all the raw materials are mixed together, although ultrasonic cavitation mixing is carried out, it is not as good as the effect of separately dissolving and mixing in different solvents step by step, thereby resulting in a deterioration of the inhibition effect.

[0024] (3) The ionic liquid can synergistically inhibit polymerization with tert-butylcatechol and N,N-diethylhydroxylamine. 1-ethyl-3-methylimidazolium diethyl phosphate, as an ionic liquid, serves both as an inhibitor and as an organic solvent. It can synergistically play a better inhibition synergistic effect with tert-butylcatechol and N,N-diethylhydroxylamine, with the polymer content below 0.4 wt%. However, after replacing 1-ethyl-3-methylimidazolium diethyl phosphate with ionic liquids such as 1-butyl-3-methylimidazolium hexafluorophosphate and 1-butyl-3-methylimidazolium nitrate, the inhibition effect deteriorates. Moreover, 1-butyl-3-methylimidazolium nitrate is an ionic liquid with nitrate as the negative ion, and its use is not safe and there is a possibility of explosion. Detailed implementation mode

[0025] Example 1: The preparation method of the inhibitor is as follows:

[0026] Step 1: Weigh each component according to 14 wt% of tert-butylcatechol, 7 wt% of N,N-diethylhydroxylamine, 4 wt% of 1-ethyl-3-methylimidazolium diethylphosphate, 65 wt% of solvent oil No. 180, and 10 wt% of mesitylene; Step 2: Add tert-butylcatechol to solvent oil No. 180 and perform ultrasonic cavitation for 20 min to obtain solution A; Step 3: Add N,N-diethylhydroxylamine to mesitylene and perform ultrasonic cavitation for 10 min to obtain solution B; Step 4: Mix solution A, solution B, and 1-ethyl-3-methylimidazolium diethylphosphate, and perform ultrasonic cavitation for 30 min to obtain the inhibitor.

[0027] Example 2: A method for preparing an inhibitor, the specific steps are as follows:

[0028] Step 1: Weigh each component according to 11 wt% of tert-butylcatechol, 9 wt% of N,N-diethylhydroxylamine, 5 wt% of 1-ethyl-3-methylimidazolium diethylphosphate, 68 wt% of solvent oil No. 180, and 7 wt% of naphthalene; Step 2: Add tert-butylcatechol to solvent oil No. 180 and perform ultrasonic cavitation for 30 min to obtain solution A; Step 3: Add N,N-diethylhydroxylamine to naphthalene and perform ultrasonic cavitation for 20 min to obtain solution B; Step 4: Mix solution A, solution B, and 1-ethyl-3-methylimidazolium diethylphosphate, and perform ultrasonic cavitation for 40 min to obtain the inhibitor.

[0029] Example 3: A method for preparing an inhibitor, the specific steps are as follows:

[0030] Step 1: Weigh each component according to 16 wt% of tert-butylcatechol, 6 wt% of N,N-diethylhydroxylamine, 3 wt% of 1-ethyl-3-methylimidazolium diethylphosphate, 60 wt% of solvent oil No. 180, and 15 wt% of toluene; Step 2: Add tert-butylcatechol to solvent oil No. 180 and perform ultrasonic cavitation for 15 min to obtain solution A; Step 3: Add N,N-diethylhydroxylamine to naphthalene and perform ultrasonic cavitation for 5 min to obtain solution B; Step 4: Mix solution A, solution B, and 1-ethyl-3-methylimidazolium diethylphosphate, and perform ultrasonic cavitation for 15 min to obtain the inhibitor.

[0031] Comparative Example 1: Preparation method of inhibitor, the specific steps are as follows: Step 1, weigh each component according to 14 wt% of tert-butylcatechol, 7 wt% of N,N-diethylhydroxylamine, 4 wt% of 1-ethyl-3-methylimidazolium diethyl phosphate, 65 wt% of No. 180 solvent oil, and 10 wt% of mesitylene; Step 2, add tert-butylcatechol to No. 180 solvent oil and stir magnetically for 20 min to obtain solution A; Step 3, add N,N-diethylhydroxylamine to mesitylene and stir magnetically for 10 min to obtain solution B; Step 4, mix solution A, solution B and 1-ethyl-3-methylimidazolium diethyl phosphate, and stir magnetically for 30 min to obtain the inhibitor.

[0032] Comparative Example 2: Preparation method of inhibitor, the specific steps are as follows: Step 1, weigh each component according to 14 wt% of tert-butylcatechol, 7 wt% of N,N-diethylhydroxylamine, 4 wt% of 1-ethyl-3-methylimidazolium diethyl phosphate, 65 wt% of No. 180 solvent oil, and 10 wt% of mesitylene; Step 2, mix tert-butylcatechol, N,N-diethylhydroxylamine, 1-ethyl-3-methylimidazolium diethyl phosphate, No. 180 solvent oil and mesitylene together, and carry out ultrasonic cavitation for 60 min to obtain the inhibitor.

[0033] Comparative Example 3: Preparation method of inhibitor, the specific steps are as follows:

[0034] Step 1, weigh each component according to 14 wt% of tert-butylcatechol, 7 wt% of N,N-diethylhydroxylamine, 4 wt% of 1-butyl-3-methylimidazolium hexafluorophosphate, 65 wt% of No. 180 solvent oil, and 10 wt% of mesitylene; Step 2, add tert-butylcatechol to No. 180 solvent oil and carry out ultrasonic cavitation for 20 min to obtain solution A; Step 3, add N,N-diethylhydroxylamine to mesitylene and carry out ultrasonic cavitation for 10 min to obtain solution B; Step 4, mix solution A, solution B and 1-butyl-3-methylimidazolium hexafluorophosphate, and carry out ultrasonic cavitation for 30 min to obtain the inhibitor.

[0035] Comparative Example 4: Preparation method of inhibitor, the specific steps are as follows:

[0036] Step 1, weigh each component according to 14 wt% of tert-butylcatechol, 7 wt% of N,N-diethylhydroxylamine, 1-butyl-3-methylimidazolium nitrate, 65 wt% of No. 180 solvent oil, and 10 wt% of mesitylene; Step 2, add tert-butylcatechol to No. 180 solvent oil and carry out ultrasonic cavitation for 20 min to obtain solution A; Step 3, add N,N-diethylhydroxylamine to mesitylene and carry out ultrasonic cavitation for 10 min to obtain solution B; Step 4, mix solution A, solution B and 1-butyl-3-methylimidazolium nitrate, and carry out ultrasonic cavitation for 30 min to obtain the inhibitor.

[0037] Comparative Example 5: Preparation method of inhibitor, the specific steps are as follows:

[0038] Step 1, weigh each component according to 14 wt% of tert-butylcatechol, 11 wt% of N,N-diethylhydroxylamine, 65 wt% of No. 180 solvent oil, and 10 wt% of mesitylene; Step 2, add tert-butylcatechol to No. 180 solvent oil and perform ultrasonic cavitation for 20 min to obtain solution A; Step 3, add N,N-diethylhydroxylamine to mesitylene and perform ultrasonic cavitation for 10 min to obtain solution B; Step 4, mix solution A and solution B, and perform ultrasonic cavitation for 30 min to obtain the inhibitor.

[0039] Comparative Example 6: Preparation method of inhibitor, the specific steps are as follows:

[0040] Step 1, weigh each component according to 14 wt% of tert-butylcatechol, 11 wt% of 1-ethyl-3-methylimidazolium diethyl phosphate, 65 wt% of No. 180 solvent oil, and 10 wt% of mesitylene; Step 2, add tert-butylcatechol to No. 180 solvent oil and perform ultrasonic cavitation for 20 min to obtain solution A; Step 3, mix solution A, mesitylene, and 1-ethyl-3-methylimidazolium diethyl phosphate, and perform ultrasonic cavitation for 30 min to obtain the inhibitor.

[0041] Comparative Example 7: Preparation method of inhibitor, the specific steps are as follows:

[0042] Step 1, weigh each component according to 21 wt% of N,N-diethylhydroxylamine, 4 wt% of 1-ethyl-3-methylimidazolium diethyl phosphate, 65 wt% of No. 180 solvent oil, and 10 wt% of mesitylene; Step 2, add N,N-diethylhydroxylamine to mesitylene and perform ultrasonic cavitation for 10 min to obtain solution A; Step 3, mix solution A, No. 180 solvent oil, and 1-ethyl-3-methylimidazolium diethyl phosphate, and perform ultrasonic cavitation for 30 min to obtain the inhibitor.

[0043] Comparative Example 8: Preparation method of inhibitor, the specific steps are as follows:

[0044] Step 1, weigh each component according to 14 wt% of tert-butylcatechol, 7 wt% of N,N-diethylhydroxylamine, 4 wt% of 1-ethyl-3-methylimidazolium diethyl phosphate, and 75 wt% of mesitylene; Step 2, add tert-butylcatechol to half of the mesitylene and perform ultrasonic cavitation for 20 min to obtain solution A; Step 3, add N,N-diethylhydroxylamine to the remaining half of the mesitylene and perform ultrasonic cavitation for 10 min to obtain solution B; Step 4, mix solution A, solution B, and 1-ethyl-3-methylimidazolium diethyl phosphate, and perform ultrasonic cavitation for 30 min to obtain the inhibitor.

[0045] Determination of inhibitor: Add the inhibitors prepared in the above-mentioned examples and comparative examples in the required amounts to the C5 fraction material (wherein, the determination of the component content of the C5 fraction material is carried out by using a Shimadzu gas chromatograph to measure the change of C5 components and calculated by the area normalization method). The amount of inhibitor maintained in the C5 fraction material is 100 ppm in terms of the total amount of tert-butylcatechol, N,N-diethylhydroxylamine and 1-ethyl-3-methylimidazolium diethylphosphate. Fill it into a glass tube and seal it well. Place the sealed tube in a constant temperature oil bath at 140 °C for 15 hours, take it out and cool it to room temperature, and weigh it as M1. Add a precipitant and centrifuge it, then place it in a vacuum drying oven and dry it for 1 hour under the conditions of a temperature of 120 °C and a vacuum degree of 0.05 MPa. Take out the sample, cool it and weigh it to obtain the weight M2. Polymer content (wt%) = (M2 / M1) 100%, and the polymer contents of each example and comparative example are shown in Table 1.

[0046] Table 1 Polymer content

[0047] Polymer content (wt%) Example 1 0.34 Example 2 0.36 Example 3 0.39 Comparative Example 1 0.52 Comparative Example 2 0.55 Comparative Example 3 0.86 Comparative Example 4 0.82 Comparative Example 5 2.25 Comparative Example 6 2.05 Comparative Example 7 2.13 Comparative Example 8 0.86

[0048] By comparing Example 1 with Comparative Examples 1-2, in the preparation method of the present invention, No. 180 solvent oil and mesitylene are used as solvents to dissolve tert-butylcatechol and N,N-diethylhydroxylamine respectively, and ultrasonic cavitation is used during the dissolution process to promote dissolution and mixing. The ionic liquid 1-ethyl-3-methylimidazolium diethylphosphate serves as both an inhibitor and an organic solvent, and under the action of ultrasonic waves, it is uniformly mixed with the above two solutions to form an inhibitor, and its inhibition effect is better, and the polymer content is below 0.4 wt%. When mixing is carried out by the action of mechanical forces such as magnetic stirring, the mixing effect is not as good as ultrasonic cavitation, resulting in a worse inhibition effect than ultrasonic cavitation. And when all raw materials are mixed together, although ultrasonic cavitation mixing is carried out, it is not as good as the effect of dissolving and mixing separately in different solvents step by step, which in turn leads to a deterioration of the inhibition effect.

[0049] By comparing Example 1 with Comparative Examples 3-4, the ionic liquid can cooperate with tert-butylcatechol and N,N-diethylhydroxylamine for inhibition. Through experiments, it is found that the ionic liquid 1-ethyl-3-methylimidazolium diethylphosphate serves as both an inhibitor and an organic solvent, and it can cooperate with tert-butylcatechol and N,N-diethylhydroxylamine to play a better inhibition synergistic effect, and the polymer content is below 0.4 wt%. After using 1-butyl-3-methylimidazolium hexafluorophosphate and 1-butyl-3-methylimidazolium nitrate to replace 1-ethyl-3-methylimidazolium diethylphosphate, the inhibition effect becomes worse, and 1-butyl-3-methylimidazolium nitrate is an ionic liquid with nitrate as the negative ion, and its use is not safe and there is a possibility of explosion.

[0050] By comparing Example 1 with Comparative Examples 5-8, it is disclosed in the prior art that the combination of tert-butylcatechol and N,N-diethylhydroxylamine as inhibitors has a good synergistic effect and enhances the inhibition effect. Surprisingly, through experiments, it is found that after compounding 1-ethyl-3-methylimidazolium diethyl phosphate with tert-butylcatechol and N,N-diethylhydroxylamine, the three of them have an obvious synergistic effect. 1-ethyl-3-methylimidazolium diethyl phosphate plays multiple roles. It is an ionic liquid inhibitor that can synergistically inhibit polymerization with tert-butylcatechol, and it can also act as an organic solvent and be compounded with solvent oil No. 180 and xylene as a compounding solvent to improve the inhibition effect. At the same time, due to its phosphate ester structure, it can also have a good synergistic and enhancing effect with N,N-diethylhydroxylamine. Therefore, the inhibition effect achieved by compounding any two of the above inhibitors is significantly weaker than that achieved by compounding the three. When removing solvent oil No. 180, its inhibition effect also deteriorates.

[0051] The above are only exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An inhibitor for inhibiting the polymerization of olefins in cracked C5 fraction of petroleum, characterized in that, The inhibitor is composed of component 1, component 2, component 3, solvent 1 and solvent 2. Component 1 is tert-butylcatechol, component 2 is N,N-diethylhydroxylamine, component 3 is 1-ethyl-3-methylimidazolium diethylphosphate, solvent 1 is solvent oil No. 180, and solvent 2 is mesitylene, toluene, xylene, naphthalene. The weight percentage of component 1 in the inhibitor is 11-16 wt%, the weight percentage of component 2 is 6-9 wt%, the weight percentage of component 3 is 3-5 wt%, the weight percentage of solvent 1 is 60-68 wt%, and the weight percentage of solvent 2 is 7-15 wt%. The sum of the weight percentages of component 1, component 2 and component 3 is below 25 wt%. The preparation method of the inhibitor is as follows: Step 1, weigh each component and solvent according to the weight percentage of the inhibitor; Step 2, add component 1 to solvent 1 and perform ultrasonic cavitation to obtain solution A; Step 3, add component 2 to solvent 2 and perform ultrasonic cavitation to obtain solution B; Step 4, mix solution A, solution B and component 3, and perform ultrasonic cavitation to obtain the inhibitor.

2. The inhibitor for inhibiting the polymerization of olefins in cracked C5 fraction of petroleum according to claim 1, characterized in that, The solvent 2 is mesitylene.

3. The inhibitor for inhibiting the polymerization of olefins in cracked C5 fraction of petroleum according to claim 1 or 2, characterized in that, In the inhibitor, the weight percentage of component 1 is 14 wt%, the weight percentage of component 2 is 7 wt%, the weight percentage of component 3 is 4 wt%, the weight percentage of solvent 1 is 65 wt%, and the weight percentage of solvent 2 is 10 wt%.

4. The preparation method of the inhibitor for inhibiting the polymerization of olefins in cracked C5 fraction of petroleum according to claim 1, characterized in that, The inhibitor is composed of component 1, component 2, component 3, solvent 1 and solvent 2. Component 1 is tert-butylcatechol, component 2 is N,N-diethylhydroxylamine, component 3 is 1-ethyl-3-methylimidazolium diethylphosphate, solvent 1 is solvent oil No. 180, and solvent 2 is mesitylene, toluene, xylene, naphthalene. The weight percentage of component 1 in the inhibitor is 11-16 wt%, the weight percentage of component 2 is 6-9 wt%, the weight percentage of component 3 is 3-5 wt%, the weight percentage of solvent 1 is 60-68 wt%, and the weight percentage of solvent 2 is 7-15 wt%. The sum of the weight percentages of component 1, component 2 and component 3 is below 25 wt%. The preparation method of the inhibitor is as follows: Step 1, weigh each component and solvent according to the weight percentage of the inhibitor; Step 2, add component 1 to solvent 1 and perform ultrasonic cavitation to obtain solution A; Step 3, add component 2 to solvent 2 and perform ultrasonic cavitation to obtain solution B; Step 4, mix solution A, solution B and component 3, and perform ultrasonic cavitation to obtain the inhibitor.

5. The preparation method according to claim 4, characterized in that, The solvent 2 is mesitylene.

6. The preparation method according to claim 4, characterized in that, In the inhibitor, the weight percentage of component 1 is 14 wt%, the weight percentage of component 2 is 7 wt%, the weight percentage of component 3 is 4 wt%, the weight percentage of solvent 1 is 65 wt%, and the weight percentage of solvent 2 is 10 wt%.

7. The preparation method according to claim 4, characterized in that, In Step 2, the ultrasonic cavitation time is 15-30 min, in Step 3, the ultrasonic cavitation time is 5-20 min, and in Step 4, the ultrasonic cavitation time is 15-40 min.

8. A method for inhibiting the polymerization of olefins in cracked C5 fraction of petroleum by using the inhibitor according to any one of claims 1 - 3, the method comprising adding the inhibitor to the C5 fraction material and maintaining a certain amount of the inhibitor in the C5 fraction material, and the amount of the inhibitor maintained in the C5 fraction material is 50 - 400 ppm based on the total amount of component 1, component 2 and component 3.

9. The method according to claim 8, characterized in that, The amount of inhibitor maintained in the C5 fraction material is 100 ppm based on the total amount of Component 1, Component 2, and Component 3, and the polymer content is below 0.39 wt%.