A detergent dispersant, an ethylene polymerization inhibitor and a method for preparing the same

Abstract

The present application belongs to the technical field of polymerization inhibitor, in particular to a kind of cleaning dispersant, ethylene polymerization inhibitor and its preparation method, the present application is through the synergic compatibility of polyisobutylene succinimide compound, high alkaline alkyl benzene sulfonate and auxiliary dispersant in specific weight ratio range in cleaning dispersant, wherein polyisobutylene succinimide compound is strongly adsorbed to the surface of polymer particles with its polar group, high alkaline alkyl benzene sulfonate neutralizes acidic by-products generated during polymer growth with its basic component and provides charge repulsion dispersion stability, auxiliary dispersant bridges between polymer particles and base oil with its moderate polarity long-chain alkyl structure, the three form "adsorption-neutralization-bridging" dispersion stability network, solve the technical problem that single dispersing component is difficult to effectively inhibit polymer particle agglomeration and deposition due to single action mechanism.

Description

Technical Field

[0001] This invention relates to the field of polymerization inhibitor technology, and in particular to a cleaning dispersant, an ethylene polymerization inhibitor, and a method for preparing the same. Background Technology

[0002] Ethylene, as an important basic organic chemical raw material, commonly suffers from polymer formation and deposition problems during its production. In process units such as compression, propane removal, butane removal, and distillation in ethylene plants, the presence of large amounts of reactive olefins (such as ethylene and propylene) and conjugated dienes (such as butadiene and isoprene) in the process media, under high temperature (80~200℃) and high pressure (2~4 MPa), readily leads to free radical polymerization and coordination polymerization reactions, generating polymer scale with a wide molecular weight distribution and strong adhesion. This scale deposits on heat exchanger tube bundles, trays, reboilers, and pipeline inner walls, resulting in decreased heat transfer efficiency, increased equipment pressure drop, and shortened operating cycles. In severe cases, it can even cause equipment blockage and unplanned shutdowns, leading to significant economic losses and safety risks in ethylene production.

[0003] To suppress polymerization and scale buildup in ethylene process streams, industrially, polymerization inhibitors are commonly added to the process medium. Existing ethylene polymerization inhibitors typically consist of free radical scavengers (such as nitrile and oxyradical compounds) and antioxidants (such as hindered phenolic compounds) as the main agents, supplemented by metal passivators and small amounts of dispersants. However, existing polymerization inhibitor systems primarily focus on preventing the initiation and propagation of polymerization reactions through chemical pathways such as free radical chain termination and oxidation inhibition, lacking effective dispersion and removal capabilities for already formed polymer scale. This results in the polymerization inhibitor, while reducing the polymerization rate to some extent during use, still causing existing scale to continuously accumulate on equipment surfaces, ultimately requiring frequent shutdowns for cleaning.

[0004] To address the aforementioned issues, some existing technologies attempt to add detergent-dispersants to polymerization inhibitors to enhance their dispersion performance against polymer scale. For example, existing technologies disclose the addition of polyisobutylene succinimide compounds as dispersing components to ethylene polymerization inhibitors. However, the detergent-dispersants used in existing technologies are mostly general-purpose dispersants commonly used in the lubricating oil industry. These dispersants have single components and simple mechanisms of action, relying solely on the polar groups of the dispersant to generate limited adsorption on the scale particle surface. They lack multi-component synergistic design tailored to the characteristics of scale in ethylene process flows. On the one hand, the presence of an adsorption-desorption balance makes it difficult to achieve stable and long-term dispersion of scale particles. On the other hand, the lack of ability to regulate the surface charge state and acidic byproducts of scale particles makes the dispersed scale particles prone to re-agglomeration and redeposition, resulting in very limited detergent-dispersing effects.

[0005] More importantly, existing polymerization inhibitors lack synergistic design among their functional components. Free radical scavengers, antioxidants, and metal passivators each act independently at a specific stage of the polymerization reaction, while detergents and dispersants are often simply mixed in as independent additives, lacking functional linkage and synergy among the components. For example, the terminating chain segments generated after the free radical scavenger's chain lengthening remain in the reaction system; if not dispersed and removed in time, they may still become active sites for secondary polymerization. The oxidation products generated after the antioxidant consumes peroxides accumulate on the metal surface; without appropriate detergent components to remove them, this can exacerbate the chemical bonding of the deposits. These technical defects caused by the lack of synergy among components limit further improvements in the polymerization inhibition efficiency of existing polymerization inhibitors.

[0006] Furthermore, existing ethylene polymerization inhibitors also have shortcomings in their preparation methods. To ensure the complete dissolution of each solid component, current preparation processes often employ relatively high heating temperatures (typically 70-90°C). However, the thermal stability of nitrile and oxyradical compounds in free radical scavengers decreases significantly at temperatures above 60°C, easily undergoing thermal decomposition or structural rearrangement and losing their free radical scavenging activity; hindered phenolic antioxidants also tend to exhibit oxidative discoloration and reduced activity at high temperatures. On the other hand, using lower dissolution temperatures can lead to insufficient dissolution of some high molecular weight components (especially dispersants), making it difficult to achieve uniform dispersion at the molecular level, thus affecting product consistency and performance. This contradiction in preparation temperature limits further improvements in the quality of polymerization inhibitor products in existing technologies.

[0007] Regarding detergent-dispersants, existing technologies generally suffer from the problem of inappropriate selection of base oil carriers. If low-viscosity base oils are used, the active components in the detergent-dispersant are prone to sedimentation and stratification during storage, resulting in poor product homogeneity. While high-viscosity base oils improve storage stability, the migration rate of active components to the surface of scale particles is limited under the high-temperature conditions of the ethylene process flow, affecting the immediacy of the dispersion effect. Furthermore, the existing detergent-dispersant preparation process often omits the filtration step or only uses coarse filtration. The insoluble particles remaining in the product, when added to the ethylene process flow, may instead become new polymer nucleation sites, inducing accelerated local polymerization reactions. This safety hazard has not been effectively addressed in existing technologies.

[0008] In summary, the existing technology has at least the following technical problems: First, the polymerization inhibitor system lacks efficient cleaning and dispersing capabilities for existing scale, leading to continuous scale accumulation and short equipment operating cycles; Second, the cleaning and dispersing agent has a single component and lacks multi-component synergy, resulting in limited and unsustainable dispersion effects; Third, there is a lack of synergistic interaction among the functional components of the polymerization inhibitor, with each component acting independently, making it difficult to further improve the overall polymerization inhibition efficiency; Fourth, the contradiction between heating temperature and component thermal stability in the preparation method leads to product activity loss or uneven dispersion; Fifth, inappropriate selection of base oil carrier and lack of filtration processes result in insufficient product storage stability and safety in use. Summary of the Invention

[0009] To address the aforementioned problems, this invention proposes a cleaning dispersant, an ethylene polymerization inhibitor, and a method for preparing the same, thereby more accurately resolving the issues raised in the background section.

[0010] This invention is achieved through the following technical solution:

[0011] This invention proposes a detergent-dispersant, characterized in that, by weight, it comprises the following components: 20-60 parts of polyisobutylene succinimide compound; 10-40 parts of highly basic alkylbenzene sulfonate; 5-25 parts of auxiliary dispersant; and 10-40 parts of base oil; the detergent-dispersant is used to inhibit polymer deposition in the ethylene process.

[0012] Preferably, the polyisobutylene succinimide compound has a number-average molecular weight of 800-3000 for the polyisobutylene group, and the polyisobutylene succinimide compound is selected from polyisobutylene bis(succinimide) and / or polyisobutylene poly(succinimide).

[0013] Preferably, the total base value of the highly basic alkylbenzene sulfonate is not less than 250 mg KOH / g, and the highly basic alkylbenzene sulfonate is selected from highly basic calcium alkylbenzene sulfonate and / or highly basic magnesium alkylbenzene sulfonate.

[0014] Preferably, the number average molecular weight of the auxiliary dispersant is 1000-5000, and the auxiliary dispersant is selected from monoalkenyl succinimide and / or high molecular weight polyisobutylene amine.

[0015] Preferably, the base oil has a kinematic viscosity of 10~100 mm² / s at 40°C, and the base oil is selected from mineral oil and / or synthetic oil.

[0016] An ethylene polymerization inhibitor, characterized in that, by weight, it comprises the following components: 1-15 parts of a free radical scavenger; 5-30 parts of an antioxidant; 1-10 parts of a metal passivator; 10-40 parts of the detergent-dispersant; and 30-70 parts of an organic solvent; wherein the free radical scavenger, the antioxidant, the metal passivator, and the detergent-dispersant have a synergistic polymerization inhibitory effect.

[0017] Preferably, the free radical scavenger is selected from 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical and / or N,N-di-tert-butyl nitroxide radical; the antioxidant is selected from 2,6-di-tert-butyl-p-cresol and / or N-phenyl-α-naphthylamine.

[0018] Preferably, the metal passivating agent is selected from benzotriazole and / or N,N′-disalynyl-1,2-propanediamine; the organic solvent is an aromatic solvent and / or a polar solvent, and the boiling point of the organic solvent is 80~200℃.

[0019] A method for preparing an ethylene polymerization inhibitor, characterized by comprising the following steps: adding an organic solvent to a reaction vessel and heating it to 40-60°C under stirring; adding a free radical scavenger, an antioxidant, and a metal passivator to the reaction vessel and stirring until completely dissolved; adding a detergent dispersant to the reaction vessel and continuing to stir and mix for 0.5-2 hours; cooling to room temperature and filtering to obtain the ethylene polymerization inhibitor.

[0020] Preferably, the stirring speed is 100~500 rpm, and the heating is carried out by water bath heating or oil bath heating.

[0021] Compared with the prior art, the present invention provides a cleaning dispersant, an ethylene polymerization inhibitor, and a method for preparing the same, which has the following beneficial effects:

[0022] This detergent-dispersant, ethylene polymerization inhibitor, and their preparation method utilize the synergistic combination of polyisobutylene succinimide compounds, highly basic alkylbenzene sulfonates, and auxiliary dispersants within a specific weight ratio range in the detergent-dispersant. The polyisobutylene succinimide compounds, with their polar groups, exert a strong adsorption effect on the surface of polymer particles. The highly basic alkylbenzene sulfonates, with their alkaline components, neutralize the acidic byproducts generated during polymer growth and provide charge-repulsion dispersion stabilization. The auxiliary dispersant, with its moderately polar long-chain alkyl structure, bridges the polymer particles and base oil. Together, these three components form an "adsorption-neutralization-bridging" dispersion stabilization network. This solves the technical problem that single dispersing components, due to their singular mechanism of action, are unable to effectively inhibit polymer particle aggregation and deposition. It achieves efficient transfer and stable dispersion of polymer deposits from the metal surface to the liquid phase in the ethylene process flow.

[0023] This cleaning dispersant, ethylene polymerization inhibitor, and their preparation method limit the number-average molecular weight of the polyisobutylene succinimide compound to 800-3000 and the number-average molecular weight of the auxiliary dispersant to 1000-5000. These two components form a three-dimensional stable layer at the molecular scale, with interwoven long and short chains. The shorter molecular chains of the polyisobutylene succinimide compound rapidly adsorb onto the surface of the scale particles to form an initial coating layer, while the longer molecular chains of the auxiliary dispersant further extend outward to provide stronger steric hindrance. This gradient matching structure of molecular chain length solves the technical problem in existing technologies where the adsorption rate and dispersion stability are difficult to balance due to excessively long or short dispersant molecular chains. It achieves a dual guarantee of rapid capture and long-term stability of polymer scale particles.

[0024] This detergent-dispersant, ethylene polymerization inhibitor, and their preparation method utilize a base oil with a kinematic viscosity of 10~100 mm² / s at 40℃ as the carrier for the detergent-dispersant. The moderate viscosity of the base oil ensures both uniform dispersion and long-term stability of the active components of the detergent-dispersant during storage and use, and also ensures that the active components can quickly migrate to the surface of the scale particles to perform adsorption and dispersion under the high-temperature conditions of the ethylene process flow. This solves the technical contradiction of poor fluidity of high-viscosity carriers leading to slow release of active components and poor storage stability of low-viscosity carriers leading to component stratification and sedimentation, thus achieving a balance between the storage stability and immediate use of the detergent-dispersant product.

[0025] This detergent-dispersant, ethylene polymerization inhibitor, and its preparation method combine a free radical scavenger, an antioxidant, a metal passivator, and a detergent-dispersant in a specific weight ratio. The free radical scavenger preferentially captures active free radicals during the ethylene polymerization chain growth process to achieve chain termination. The antioxidant consumes dissolved oxygen and peroxides to block the oxidation-induced polymerization pathway. The metal passivator complexes with metal ions on the equipment surface to eliminate the catalytic activity of metal ions on the polymerization reaction. The detergent-dispersant simultaneously disperses and removes polymer deposits and cleans and protects the equipment surface. The four components form a closed-loop polymerization inhibition network of "terminating chain growth—blocking oxidation pathways—eliminating catalytic activity—removing deposits." This solves the technical defect of existing polymerization inhibitors that only focus on a single polymerization inhibition pathway and are difficult to comprehensively inhibit multiple polymerization initiators in the gas and liquid phases. It achieves comprehensive inhibition of homogeneous and heterogeneous polymerization in the ethylene process flow.

[0026] The cleaning and dispersing agent, ethylene polymerization inhibitor, and their preparation method, by using the cleaning and dispersing agent as the core functional component of the ethylene polymerization inhibitor, assume a dual function in the synergistic polymerization inhibition network: on the one hand, its alkaline components continuously neutralize the acidic byproducts generated during polymerization to prevent acidic substances from corroding metal equipment and chemically binding and fixing scale; on the other hand, its polar groups peel off the formed polymer scale particles from the metal surface and stably disperse them in the process flow to prevent the cumulative growth of scale. This "integrated scale removal and inhibition" functional design solves the structural problem of limited overall efficiency caused by the separation of dispersion and polymerization inhibition functions in existing polymerization inhibitor systems, and realizes the organic integration and synergistic enhancement of polymerization inhibition and cleaning functions.

[0027] This cleaning and dispersing agent, ethylene polymerization inhibitor, and their preparation method utilize aromatic solvents and / or polar solvents with boiling points of 80-200℃ as carriers for the ethylene polymerization inhibitor. Solvents within this boiling range have suitable evaporation rates during storage and use to ensure uniform dissolution and long-term stability of the inhibitor components. Furthermore, they can moderately volatilize upon contact with the ethylene process flow to release the polymerization-inhibiting active components, thereby ensuring rapid onset of polymerization inhibition. This solves the technical problems of poor product storage stability due to excessively low solvent boiling points and delayed release of active components due to excessively high boiling points, achieving a balance between stable preservation and rapid onset of polymerization inhibitor products.

[0028] This cleaning dispersant, ethylene polymerization inhibitor, and their preparation method control the heating temperature within the range of 40~60℃ during the preparation process. The lower limit of this temperature range ensures that the free radical scavenger, antioxidant, and metal passivator are fully dissolved in the organic solvent and achieve uniform dispersion at the molecular level. The upper limit of the temperature range avoids thermal degradation of nitrogen and oxygen free radicals in the free radical scavenger and oxidative failure of the antioxidant due to excessively high temperatures. This mild temperature control method solves the technical contradiction in existing preparation methods where high-temperature dissolution leads to the deactivation of heat-sensitive components and low-temperature dissolution leads to uneven dispersion of components. It achieves a uniform and stable dissolution and dispersion state for each active component while maintaining its original chemical activity. Attached Figure Description

[0029] Figure 1 This is a schematic diagram showing the weight range of each component of the detergent-dispersant, ethylene polymerization inhibitor, and preparation method of the present invention.

[0030] Figure 2 This is a schematic diagram illustrating the synergistic inhibition mechanism of an ethylene polymerization inhibitor, a cleaning and dispersing agent, an ethylene polymerization inhibitor, and their preparation method proposed in this invention.

[0031] Figure 3 This is a schematic diagram of the ethylene polymerization inhibitor preparation process of a cleaning dispersant, an ethylene polymerization inhibitor, and a preparation method thereof proposed in this invention. Detailed Implementation

[0032] To more clearly and completely illustrate the technical solution of the present invention, the following description is in conjunction with the appendix. Figures 1-3 The present invention will be further described below.

[0033] Example 1

[0034] Detergent and dispersant (by weight): 40 parts of polyisobutylene bis(succinimide) (polyisobutylene number-average molecular weight Mn=1500); 25 parts of highly alkaline alkylbenzene sulfonate (total base value 300 mg KOH / g, calcium content ≥12wt%); 15 parts of monoalkenyl succinimide (Mn=2500); 20 parts of mineral oil (kinematic viscosity 35 mm² / s at 40℃).

[0035] Ethylene polymerization inhibitors (by weight): 8 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine nitrogen oxide radical; 18 parts of 2,6-di-tert-butyl-p-cresol; 5 parts of benzotriazole; 25 parts of the above detergent dispersant; and 44 parts of xylene.

[0036] Preparation method: Xylene is added to a reaction vessel and heated to 50°C (water bath heating) with a stirring rate of 300 rpm; free radical scavenger, antioxidant and metal passivator are added and stirred until completely dissolved (about 15 minutes); detergent dispersant is added and stirring is continued for 1 hour; cooled to room temperature (25°C) and filtered through a 0.45 μm filter membrane to obtain ethylene polymerization inhibitor.

[0037] Example 2

[0038] Detergent and dispersant (by weight): 50 parts of polyisobutylene polysuccinimide (polyisobutylene Mn=2000); 30 parts of high-alkalinity alkylbenzene sulfonate (total base number 280 mg KOH / g, magnesium content ≥6.5wt%); 10 parts of high molecular weight polyisobutylene amine (Mn=3500); 10 parts of synthetic oil (polyα-olefin, kinematic viscosity at 40℃ 50 mm² / s).

[0039] Ethylene polymerization inhibitor (by weight): 5 parts N,N-di-tert-butyl nitroxide radical; 25 parts N-phenyl-α-naphthylamine; 8 parts N,N′-disalynyl-1,2-propanediamine; 35 parts of the above detergent and dispersant; 27 parts aromatic solvent (C9-C10 heavy aromatics, boiling range 145~160℃).

[0040] The preparation method is the same as in Example 1, with a heating temperature of 60°C, a stirring and mixing time of 1.5 hours, and filtration after cooling to 20°C.

[0041] Example 3

[0042] Detergent and dispersant (by weight): 30 parts of polyisobutylene bis(succinimide) (polyisobutylene Mn=1000); 35 parts of highly alkaline alkylbenzene sulfonate calcium (total base number 350 mg KOH / g, calcium content ≥14wt%); 20 parts of monoalkenyl succinimide (Mn=4000); 15 parts of mineral oil (kinematic viscosity at 40℃ 60 mm² / s).

[0043] Ethylene polymerization inhibitor (by weight): 12 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine nitrogen oxide radical; 10 parts of 2,6-di-tert-butyl-p-cresol; 10 parts of benzotriazole; 15 parts of the above detergent dispersant; 53 parts of polar solvent (ethylene glycol butyl ether, boiling point 120℃).

[0044] The preparation method is the same as in Example 1, with a heating temperature of 45°C, a stirring and mixing time of 0.5 hours, and filtration after cooling to room temperature.

[0045] Example 4

[0046] Detergent and dispersant (by weight): 55 parts of polyisobutylene bis(succinimide) (polyisobutylene Mn=2500); 20 parts of high-alkalinity alkylbenzene sulfonate calcium (total base number 320 mg KOH / g); 8 parts of high molecular weight polyisobutylene amine (Mn=4800); 17 parts of mineral oil (kinematic viscosity at 40℃ 25 mm² / s).

[0047] Ethylene polymerization inhibitors (by weight): 3 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine nitrogen oxide radical; 28 parts of 2,6-di-tert-butyl-p-cresol; 3 parts of N,N′-disalynyl-1,2-propanediamine; 18 parts of the above detergent dispersant; 48 parts of xylene.

[0048] The preparation method is the same as in Example 1, with a heating temperature of 55°C and a stirring time of 1.8 hours.

[0049] Example 5

[0050] Detergent and dispersant (by weight): 25 parts polyisobutylene polysuccinimide (polyisobutylene Mn=1200); 38 parts high-alkalinity alkylbenzene sulfonate (total base number 260 mg KOH / g); 22 parts monoalkenyl succinimide (Mn=1800); 15 parts mineral oil (kinematic viscosity 80 mm² / s at 40℃).

[0051] Ethylene polymerization inhibitor (by weight): 14 parts N,N-di-tert-butyl nitroxide radical; 8 parts N-phenyl-α-naphthylamine; 2 parts benzotriazole; 38 parts of the above detergent and dispersant; 38 parts heavy aromatic solvent (boiling point 185℃).

[0052] The preparation method is the same as in Example 1, with a heating temperature of 42°C and a stirring time of 2 hours.

[0053] II. Comparative Example

[0054] Comparative Example 1 (without detergent-dispersant)

[0055] The ethylene polymerization inhibitor composition (by weight parts) is as follows: 8 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical; 18 parts of 2,6-di-tert-butyl-p-cresol; 5 parts of benzotriazole; and 69 parts of xylene. The remaining preparation conditions are exactly the same as in Example 1.

[0056] Comparative Example 2 (The detergent dispersant has a single component, containing only polyisobutylene succinimide compounds).

[0057] The detergent-dispersant composition (by weight): 80 parts polyisobutylene bis(succinimide) (polyisobutylene Mn=1500); 20 parts mineral oil (kinematic viscosity 35 mm² / s at 40℃). It does not contain highly basic alkylbenzene sulfonates or auxiliary dispersants. The composition and preparation method of the ethylene polymerization inhibitor are the same as in Example 1.

[0058] Comparative Example 3 (the proportions of the components of the detergent-dispersant deviate from the scope of this invention)

[0059] The cleaning and dispersing agent composition (by weight parts) is as follows: 10 parts of polyisobutylene bis(succinimide) (polyisobutylene Mn=1500); 50 parts of highly basic alkylbenzene sulfonate calcium (total base number 300 mg KOH / g); 2 parts of monoalkenyl succinimide (Mn=2500); and 38 parts of mineral oil. The composition and preparation method of the ethylene polymerization inhibitor are the same as in Example 1.

[0060] Comparative Example 4 (using a conventional dispersant instead of the cleaning dispersant of this invention)

[0061] The ethylene polymerization inhibitor composition (by weight parts) is as follows: 8 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical; 18 parts of 2,6-di-tert-butyl-p-cresol; 5 parts of benzotriazole; 25 parts of conventional detergent-dispersant (monosuccinimide T151, Mn=1000); and 44 parts of xylene. The rest is the same as in Example 1.

[0062] Comparative Example 5 (the temperature in the preparation method exceeds the range of this invention)

[0063] The same ethylene polymerization inhibitor composition as in Example 1 was used, and the heating temperature in the preparation method was 80°C (exceeding the range of 40~60°C), with the other conditions being the same as in Example 1.

[0064] Comparative Example 6 (The preparation method does not include a filtration step)

[0065] The same ethylene polymerization inhibitor composition as in Example 1 was used, and the preparation method involved cooling to room temperature without filtration, with the remaining conditions being the same as in Example 1.

[0066] III. Performance Evaluation Experiment

[0067] Referring to the performance evaluation method of polymerization inhibitors in the "Petrochemical Industry Standard SH / T 0100-91", and using the static high-pressure reactor evaluation method, the polymerization inhibition performance of the ethylene polymerization inhibitors in the above examples and comparative examples was comprehensively evaluated. Evaluation conditions: temperature 120℃±1℃, pressure 3.1 MPa±0.1 MPa, time 12 hours, stirring speed 200 rpm, using the bottom material of the propane stripper in an ethylene unit as raw material (containing approximately 65wt% olefins and approximately 8wt% dienes), and the polymerization inhibitor concentration was 100 ppm (based on the total mass of the raw material). The total scale mass (polymer mass deposited on the reactor wall and stirring paddle) was determined by weighing method. The total scale mass in the blank experiment (without polymerization inhibitor) was 43.8 mg. The polymerization inhibition rate was calculated using the following formula:

[0068] Polymerization inhibition rate (%) = (Blank total scale - Scale after additive addition) / Blank total scale × 100%

[0069] Table 1 Evaluation results of polymerization inhibition performance of the examples and comparative examples

[0070]

[0071] Results analysis:

[0072] (1) The total amount of scale in Examples 1 to 5 was ≤4.15 mg, the polymerization inhibition rate was ≥90.5%, and the induction period was extended by ≥135 minutes. The data reproducibility among the examples was good, indicating that the technical solution of the present invention has a stable and reliable polymerization inhibition effect.

[0073] (2) Comparing Example 1 with Comparative Example 1, it can be seen that the polymerization inhibition rate decreased significantly to 80.5% when no detergent dispersant was used, and the induction period was shortened to 68 minutes, indicating that the addition of detergent dispersant is the key factor to improve the polymerization inhibition effect.

[0074] (3) Comparative Example 2 contains only a single type of cleaning and dispersing component. Its polymerization inhibition rate (85.8%) and induction period extension (95 minutes) are significantly lower than those of Example 1, indicating that the polyisobutylene succinimide compound, the highly basic alkylbenzene sulfonate and the auxiliary dispersant in the cleaning and dispersing agent have a synergistic effect and none of them can be omitted.

[0075] (4) Although Comparative Example 3 contains the same three types of detergent dispersant components, the polymerization inhibition rate is only 83.6% because the proportion deviates from the scope of the present invention, indicating that the compatibility ratio between components is crucial to the synergistic effect.

[0076] (5) In Comparative Example 4, a conventional detergent-dispersant was used instead of the detergent-dispersant of the present invention. The polymerization inhibition rate (84.4%) was significantly lower than that of Example 1, which proves that the detergent-dispersant combination selected in the present invention has better compatibility and synergistic polymerization inhibition effect compared with conventional dispersants in the prior art.

[0077] Table 2 Evaluation results of the individual dispersion performance of detergent dispersants

[0078] The dynamic circulation method was used to evaluate the dispersing effect of the detergent-dispersant on simulated polymer scale samples. Test conditions: 2.0 g of simulated polymer scale sample (composed of polyethylene and polybutadiene in a 1:1 mass ratio); detergent-dispersant concentration of 100 ppm; test temperature of 80℃; circulation time of 4 hours; dispersion rate was calculated using the following formula:

[0079] Dispersion rate (%) = (Solid content in the suspension after dispersion / Total amount of scale sample added) × 100%

[0080]

[0081] The results showed that the dispersion rate of the detergent dispersants in Examples 1-5 was ≥75.8%, and the particle size of the dispersed scale samples was ≤3.3 μm. In contrast, the dispersion rates of Comparative Examples 2 and 3 were only 52.1% and 48.6%, respectively, with particle sizes as high as 8.7 μm and 9.5 μm. Higher dispersion rates and smaller particle sizes indicate better dispersion effects of the detergent dispersant, and a greater ability to effectively prevent polymer deposition on equipment surfaces. This further verifies the synergistic dispersion mechanism of multiple components in the detergent dispersant of this invention under specific formulations.

[0082] IV. Synergistic Effect Verification Experiment

[0083] To verify the synergistic polymerization inhibition effect among the free radical scavenger, antioxidant, metal passivator, and detergent dispersant in this invention, the following comparative experiment was designed:

[0084] Table 3 Comparison of the effects of each component used alone and in combination

[0085]

[0086] Results analysis:

[0087] As shown in Table 3, when the free radical scavenger (A), antioxidant (B), metal passivator (C), and detergent-dispersant (D) are used individually, the polymerization inhibition rates are 34.7%, 48.9%, 19.6%, and 57.3%, respectively. The arithmetic sum of the polymerization inhibition rates of the four components individually is 160.5% (far exceeding 100%), but this simple summation does not reflect the true effect. When the four components are used in combination (E), the polymerization inhibition rate increases to 80.5%, which is higher than any single component, but still significantly lower than the theoretical summation value. When the detergent-dispersant is replaced with the detergent-dispersant of this invention (Example 1), the polymerization inhibition rate further increases to 91.2%, which is 10.7 percentage points and 6.8 percentage points higher than groups E and F, respectively.

[0088] This result proves that the components of the present invention are not simply functionally superimposed, but rather achieve a synergistic polymerization inhibition effect that surpasses the sum of the individual effects of each component through a chain-like synergistic mechanism of "free radical capture-chain termination → antioxidant synergy → metal passivation deactivation → cleaning and dispersing removal". The introduction of the cleaning and dispersing agent of the present invention is the key link to trigger the maximization of this synergistic effect.

[0089] This invention achieves an ethylene polymerization inhibitor inhibition rate of over 90% by synergistically combining polyisobutylene succinimide compounds, highly basic alkylbenzene sulfonate, and auxiliary dispersants within a specific ratio range in the detergent dispersant, and by combining the multiple synergistic polymerization inhibition effects of free radical scavengers, antioxidants, and metal passivators. The total scale content is controlled below 4.2 mg, significantly superior to the comparative example. Furthermore, the preparation method of this invention optimizes temperature, stirring, and filtration conditions, ensuring the stability and consistency of product quality.

[0090] Finally, it should be noted that the basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are suggested in this specification, and therefore remain within the spirit and scope of the exemplary embodiments of this specification. Furthermore, this specification uses specific terms to describe embodiments of this specification. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined. Moreover, unless expressly stated in the claims, the order of processing elements and sequences, the use of numbers and letters, or other names described in this specification are not intended to limit the order of the processes and methods of this specification.

[0091] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A detergent-dispersant, characterized in that, By weight, it includes the following components: 20-60 parts of polyisobutylene succinimide compounds; 10-40 parts of highly basic alkylbenzene sulfonate; 5-25 parts of auxiliary dispersant; 10-40 parts base oil; The cleaning and dispersing agent is used to inhibit polymer deposition in the ethylene process.

2. The cleaning and dispersing agent according to claim 1, characterized in that, The polyisobutylene succinimide compounds have a number-average molecular weight of 800-3000 for the polyisobutylene group, and the polyisobutylene succinimide compounds are selected from polyisobutylene bis(succinimide) and / or polyisobutylene poly(succinimide).

3. The cleaning and dispersing agent according to claim 1, characterized in that, The total base value of the highly basic alkylbenzene sulfonate is not less than 250 mg KOH / g, and the highly basic alkylbenzene sulfonate is selected from highly basic calcium alkylbenzene sulfonate and / or highly basic magnesium alkylbenzene sulfonate.

4. The cleaning and dispersing agent according to claim 1, characterized in that, The number average molecular weight of the auxiliary dispersant is 1000~5000, and the auxiliary dispersant is selected from monoalkenyl succinimide and / or high molecular weight polyisobutylene amine.

5. The cleaning and dispersing agent according to claim 1, characterized in that, The base oil has a kinematic viscosity of 10~100 mm² / s at 40°C, and the base oil is selected from mineral oil and / or synthetic oil.

6. An ethylene polymerization inhibitor, characterized in that, By weight, it includes the following components: 1-15 parts of free radical scavenger; Antioxidant 5-30 parts; 1-10 parts of metal passivating agent; 10-40 parts of the cleaning and dispersing agent as described in any one of claims 1 to 5; 30-70 parts organic solvent; The free radical scavenger, the antioxidant, the metal passivator, and the detergent-dispersant have a synergistic polymerization inhibitory effect.

7. The ethylene polymerization inhibitor according to claim 6, characterized in that, The free radical scavenger is selected from 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical and / or N,N-di-tert-butyl nitroxide radical; the antioxidant is selected from 2,6-di-tert-butyl-p-cresol and / or N-phenyl-α-naphthylamine.

8. The ethylene polymerization inhibitor according to claim 6, characterized in that, The metal passivating agent is selected from benzotriazole and / or N,N′-disalynyl-1,2-propanediamine; the organic solvent is an aromatic solvent and / or a polar solvent, and the boiling point of the organic solvent is 80~200℃.

9. A method for preparing the ethylene polymerization inhibitor as described in any one of claims 6 to 8, characterized in that, Includes the following steps: Add the organic solvent to the reaction vessel and heat to 40-60°C under stirring. Add a free radical scavenger, an antioxidant, and a metal passivator to the reaction vessel and stir until completely dissolved; Add a cleaning and dispersing agent to the reaction vessel and continue stirring and mixing for 0.5 to 2 hours; Cool to room temperature and filter to obtain the ethylene polymerization inhibitor.

10. The preparation method according to claim 9, characterized in that, The stirring speed is 100~500 rpm, and the heating is carried out by water bath heating or oil bath heating.

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