Marine fuel oil purification synergist and preparation method thereof

Abstract

The invention relates to the technical field of marine fuel oil additives, and particularly provides a marine fuel oil purification synergist and a preparation method thereof. The marine fuel oil purification synergist comprises the following components in percentage by mass: 8%-12% of a sulfur capturing agent, 15%-20% of a core-shell dispersing agent, 5%-8% of a lubricating agent, 0.5%-1% of an antioxidant, 1%-2% of a pour point depressant and the balance of a solvent. The marine fuel oil purification synergist has the advantages of high flash point, sulfur inhibition, combustion enhancement and dispersion stability. The multi-component synergistic system not only greatly improves the combustion efficiency of the marine fuel oil, but also effectively inhibits the emission of harmful substances, obviously reduces the carbon deposition and wear of an engine, and keeps the cleanliness of a fuel oil system. In practical application, the synergist shows excellent environment-friendly benefits and economic benefits, and a green fuel solution which can meet increasingly strict requirements of environment-friendly laws and regulations and can reduce the operation cost is provided for the ship industry.

Description

Technical Field

[0001] The present application relates to the technical field of fuel additives, and specifically provides a marine fuel oil detergent synergist and a preparation method thereof. Background Art

[0002] Currently, marine power systems place higher demands on fuel oil combustion efficiency optimization, particulate matter emission reduction, and sulfur compound control. However, existing marine fuel oil and its additive technologies face the following key challenges:

[0003] 1. Insufficient control of sulfide emissions: When high-sulfur residual fuel oil (sulfur content 2.5% to 3.5%) is burned, sulfur element is easily converted into sulfate particulate matter (PM 2.5 ) (accounting for more than 8wt%) and hydrogen sulfide (H2S) (concentration in exhaust gas>50ppm), which leads to the deactivation of the SCR (selective catalytic reduction) post-treatment system catalyst (sulfur poisoning rate>0.3% / 100h), and at the same time increases the risk of excessive SOx emissions from ship exhaust.

[0004] 2. Conflict between combustion efficiency and soot: The high viscosity of fuel oil (50°C kinematic viscosity > 180 cSt) leads to larger atomized particle size (D90 > 50 μm), which expands the local oxygen-deficient area in the combustion chamber. Soot generation reaches 0.15-0.2 g / kWh (exceeding the Tier III limit by more than 50%), and unburned hydrocarbon (UHC) emissions increase by 3%-5%, with thermal efficiency loss > 4%.

[0005] 3. Dispersion stability and oxidative decay issues: Fuel oil has a high asphaltene and colloid content (>8wt%), and colloid aggregation is prone to occur during storage and combustion (Zeta potential <25mV), resulting in the sedimentation and separation of the effective ingredients of the additive (centrifugal stability <48h); at the same time, the free radical chain reaction generated by high-temperature oxidation makes the oil oxidation induction period <60min (ASTMD6186), accelerating the formation of carbon deposit precursors (sediment >15mg / kg).

[0006] Although existing additive technology improves combustion efficiency through metal-based catalysts, it has the following limitations: 1. Sulfur-efficiency contradiction: Traditional calcium / magnesium-based detergents react with elemental sulfur to form CaSO4 / MgSO4 hard deposits (particle size >10μm), which clog the injector aperture (pressure difference increase >0.2MPa / 100h); 2. Dispersion failure: Single polyisobutylene amine (PIBA) dispersants cannot maintain micelle stability in high-viscosity media (HLB value mismatch >3), resulting in an active ingredient deactivation rate >30%; 3. Oxidative runaway: Phenolic ester antioxidants have a reduced free radical capture ability in a high-sulfur environment (oxidation onset temperature decreases >15°C), accelerating sludge formation (TAN increase >2mg KOH / g).

[0007] Marine fuel oil detergents and synergists are chemical additives that improve the combustion characteristics of marine fuel, increasing combustion efficiency and reducing pollutant emissions, including sulfur oxides (SOx), nitrogen oxides (NOx), and particulate matter (PM). These additives alter the fuel's chemical structure, promoting a more complete combustion process, thereby reducing unburned fuel emissions and lowering greenhouse gas emissions. Fuel oil detergent and synergist technology is a general term for innovative fuel additives that save fuel, reduce emissions, and lower carbon emissions. Efficiency enhancement refers to fuel savings, emission reductions, and carbon reduction.

[0008] Existing detergent synergists still face the problem of multi-target synergistic failure, such as:

[0009] 1. Functional antagonism: Combustion-promoting components (such as metal organic compounds) and sulfur inhibitors (such as molybdates) are prone to precipitation reactions (precipitation rate > 20%) when compounded, resulting in loss of effective ingredients; 2. Insufficient dynamic stability: In high-viscosity fuel oil, the synergistic effect of dispersants and antioxidants is limited by the difference in interfacial tension (Δγ > 5mN / m), and performance degradation after long-term storage is > 40%; 3. Low sulfur conversion inhibition efficiency: Traditional sulfur scavengers (such as zinc oxide) have an adsorption capacity for H2S of < 50mg / g and a desorption rate of > 30% at high temperatures, which cannot meet the requirement of a comprehensive sulfur oxide emission reduction rate of > 85%.

[0010] Therefore, there is an urgent need to develop a multifunctional additive that can synergistically improve combustion efficiency, inhibit sulfur form conversion, enhance the dispersion stability of high-viscosity systems and delay oxidative decay, so as to meet the urgent needs of the low-carbon and clean transformation of the shipping industry, for example.

[0011] In view of this, this application is hereby filed. Summary of the Invention

[0012] One of the purposes of the present application is to provide a marine fuel oil detergent synergist and a preparation method thereof, so as to alleviate the problems of low sulfur emission reduction efficiency, prominent combustion soot contradiction, poor dispersion stability and multi-component synergistic failure of detergent synergists in the prior art.

[0013] In order to achieve the above objectives, this application adopts the following technical solutions:

[0014] A marine fuel oil detergent synergist, comprising the following components, calculated by mass percentage: 8% to 12% sulfur scavenger, 15% to 20% core-shell dispersant, 5% to 8% lubricant, 0.5% to 1% antioxidant, and 1% to 2% pour point depressant, with the balance being solvent;

[0015] The sulfur capture agent is a Zr-Mg complex, which achieves sulfur selective adsorption through Zr-O-Mg active sites;

[0016] The core-shell dispersant is a PIBSI-polyetheramine core-shell crosslinked compound, wherein PIBSI is the core and polyetheramine is the shell;

[0017] The lubricant is boronated glyceride.

[0018] Furthermore, the sulfur scavenger is Zr 4+ -MgO complex, optionally, the sulfur capture agent is a Zr(NO3)4-MgO complex;

[0019] Optionally, the sulfur scavenger has a sulfur adsorption capacity of not less than 15 mg S / g;

[0020] Optionally, the PIBSI-polyetheramine core-shell crosslinked product has a thermal weight loss of no more than 5% under high temperature conditions of 300°C;

[0021] Optionally, the boron content of the boronated glyceride is in the range of 3.5 wt% to 4.0 wt%.

[0022] Further, the antioxidant is alkylated diphenylamine;

[0023] Optionally, the antioxidant has an oxidation induction period of not less than 120 minutes at 150°C;

[0024] Optionally, the pour point depressant is polymethacrylate with a molecular weight of 8000;

[0025] Optionally, the pour point depressant reduces the pour point of the fuel oil by more than 15°C.

[0026] Furthermore, the solvent is a mixed solution of hydrogenated terphenyl and nitroethane;

[0027] Optionally, the nitroethane accounts for 15 vol% to 30 vol% in the solvent;

[0028] Optionally, the flash point of the solvent is not lower than 62°C.

[0029] The preparation method of the above-mentioned marine fuel oil detergent synergist comprises heating the solvent to 40-60°C, adding an antioxidant and mixing evenly, then sequentially adding a lubricant and a core-shell dispersant and mixing evenly, then sequentially adding a sulfur scavenger and a pour point depressant, and mixing evenly using a high-pressure homogenizer at 40-52 MPa to obtain the marine fuel oil detergent synergist.

[0030] Furthermore, the preparation method comprises the following steps:

[0031] S1 pre-mixing stage: heat the solvent to 45-50°C, add the antioxidant and stir to dissolve, then add the lubricant and stir at 45-50°C, 800-900 rpm for 30 minutes, then add the core-shell dispersant and stir at 55-60°C, 1200-1300 rpm for 1 hour;

[0032] S2 final mixing and homogenization stage: slowly add sulfur scavenger, disperse with the aid of 30-40kHz ultrasound for 30 minutes, then add pour point depressant and mix at 35-40℃ for 30 minutes, and finally pass through a high-pressure homogenizer at 45-50MPa for 3 cycles.

[0033] Furthermore, under the condition of pH 6.3-6.7, the modified nano-MgO reacts with zirconium nitrate to obtain a sulfur capture agent after separation and drying.

[0034] Optionally, the composite reaction is carried out at 50-70° C. for 1.5-2.5 hours, and the molar ratio of Zr to Mg is 1:2-1:3;

[0035] Optionally, the modifier of nano-MgO is silane coupling agent KH-550;

[0036] Optionally, the modification condition is 50-80° C. for 1.5-2.5 hours;

[0037] Optionally, the particle size of nano-MgO is 50-70 nm.

[0038] Furthermore, the preparation method of the core-shell dispersant includes:

[0039] (a) PIBSI core synthesis stage: PIBSA is reacted with polyamines under inert gas conditions with an acid value not exceeding 2 mg KOH / g, and then dried to obtain the PIBSI core;

[0040] (b) polyetheramine grafting stage: the PIBSI core in (a) is reacted with polyetheramine in the presence of a catalyst, and unreacted monomers are removed to obtain a core-shell dispersant;

[0041] Optionally, the polyamine in (a) is TEPA, the reaction conditions are 80-130° C. for 3-4 hours, and the moisture content of the PIBSI core is ≤0.5%;

[0042] Optionally, the catalyst in (b) is at least one of 0.08 wt% to 0.1 wt% of dibutyltin dilaurate, 0.05 wt% of stannous octoate and 0.02 wt% of p-toluenesulfonic acid, and the reaction conditions are 140-170° C. for 3-4 hours.

[0043] Furthermore, boric acid and glycerol are reacted at a molar ratio of 1:3 to 1:3.5 at 120 to 160° C. under nitrogen protection for 5 to 6 hours to obtain the lubricant.

[0044] The method for using the above-mentioned marine fuel oil detergent synergist comprises: using the marine fuel oil as light diesel oil and using the detergent synergist at a mass ratio of 1:1600 to 1:1400.

[0045] Alternatively, the marine fuel oil is low-sulfur fuel oil (LSFO, below 0.5%), and the mass ratio of detergent synergist to low-sulfur fuel oil is 1:1400 to 1:1200;

[0046] Alternatively, the marine fuel oil is high sulfur oil (HSFO, above 3.5%), and is used at a mass ratio of detergent synergist to high sulfur oil of 1:1200 to 1:1000.

[0047] Compared with the prior art, the technical effects of this application are:

[0048] This application provides a marine fuel oil detergent enhancer that combines the advantages of a high flash point, sulfur suppression, combustion enhancement, and dispersion stability. Through the synergistic effect of an innovative composite metal sulfur scavenger, a core-shell dispersant, and a special lubricant, the comprehensive performance of the fuel oil is significantly improved. This marine fuel oil detergent enhancer adopts a unique formula design. The sulfur scavenger utilizes Zr-O-Mg active sites to efficiently remove sulfides through a dual mechanism of chemical adsorption and physical adsorption; the core-shell dispersant ensures the stable dispersion of the enhancer under high temperature conditions through the dual effects of core anchoring and shell steric hindrance; and the special lubricant forms a self-healing protective film with the metal surface of the sulfur scavenger. This multi-component synergistic system not only significantly improves the combustion efficiency of the fuel oil, but also effectively suppresses harmful emissions, significantly reduces engine carbon deposits and wear, and maintains the cleanliness of the fuel system. In practical applications, the enhancer has demonstrated excellent environmental and economic benefits and is suitable for the combustion of high-sulfur fuel oil, especially in the shipping industry. It provides the shipping industry with a green fuel solution that can both meet increasingly stringent environmental regulations and reduce operating costs, and has broad market application prospects.

[0049] The preparation method of the marine fuel oil detergent synergist provided in this application has an innovative preparation process that ensures the stability and reliability of product performance by precisely controlling reaction conditions and key parameters. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the technical solution of the present application, the technical solution of the present application is further described in detail below in conjunction with specific implementation methods.

[0051] In this application, “further”, “further”, “particularly”, etc. are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of the present invention.

[0052] In this application, the terms "optionally," "optional," and "optional" mean optional or dispensable, i.e., they refer to either option being selected from two parallel options: "with" or "without." If a technical solution contains multiple "optional" clauses, each "optional" clause is independent unless otherwise specified and there are no contradictions or constraints.

[0053] In this application, "plurality", "multiple", "multiple times", "multiples", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0054] The present application provides a marine fuel oil detergent synergist, which comprises the following components, calculated by mass percentage: 8% to 12% sulfur scavenger, 15% to 20% core-shell dispersant, 5% to 8% lubricant, 0.5% to 1% antioxidant and 1% to 2% pour point depressant, with the balance being solvent; the sulfur scavenger is a Zr-Mg complex, which achieves sulfur selective adsorption through Zr-O-Mg active sites; the core-shell dispersant is a PIBSI-polyetheramine core-shell crosslinked material, wherein PIBSI is the core and the polyetheramine is the shell; and the lubricant is boronated glyceride.

[0055] The content of the sulfur scavenger may be, but is not limited to, 8%, 9%, 10%, 11% or 12%; the content of the core-shell dispersant may be, but is not limited to, 15%, 16%, 17%, 18%, 19% or 20%; the content of the lubricant may be, but is not limited to, 5%, 6%, 7% or 8%; the content of the antioxidant may be, but is not limited to, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%; and the content of the pour point depressant may be, but is not limited to, 1%, 1.2%, 1.4%, 1.6%, 1.8% or 2%.

[0056] The sulfur capture agent of the present application is a Zr-Mg bimetallic complex, and the Zr generated by the hydrolysis of the zirconium compound is 4+ It forms [Zr-O-Mg] active sites with the hydroxyl groups on the surface of MgO, significantly improving the sulfur adsorption selectivity.

[0057] The core-shell dispersant of the present application adopts a PIBSI-polyetheramine core-shell structure. The polyetheramine shell forms steric hindrance at high temperature, and the PIBSI core realizes a dual stabilization mechanism through polar anchoring.

[0058] The lubricant of the present application is boronated glycerol ester, and the BOC bond coordinates with the oxygen vacancies on the surface of the Zr-Mg complex to form a self-repairing lubricating film, which greatly improves the lubrication performance.

[0059] The marine fuel oil detergent synergist provided in this application achieves deep sulfur oxide emission reduction, improved combustion efficiency, reduced carbon soot emissions, and enhanced stability through the synergistic effect of composite catalysis, dispersion and antioxidant systems, while eliminating the antagonistic effect of functional components, meeting the current dual needs of fuel cleaning and low carbonization, and is particularly suitable for ship fuel cleaning and low carbonization.

[0060] In some embodiments, the sulfur capture agent is Zr 4+ -MgO composite, optionally, a Zr(NO3)4-MgO composite, optionally, the sulfur scavenger has a sulfur adsorption capacity of not less than 15 mg S / g.

[0061] In some embodiments, the thermal weight loss of the PIBSI-polyetheramine core-shell crosslinked material under high temperature conditions of 300° C. does not exceed 5%.

[0062] In some embodiments, the boron content of the boronated glyceride is in the range of 3.5 wt% to 4.0 wt%.

[0063] In some embodiments, the antioxidant is an alkylated diphenylamine; optionally, the antioxidant has an oxidation induction period of not less than 120 minutes at 150°C.

[0064] In some embodiments, the pour point depressant is polymethacrylate with a molecular weight of 8000; optionally, the pour point depressant reduces the pour point of the fuel oil by more than 15°C.

[0065] In some embodiments, the solvent is a mixed solution of hydrogenated terphenyl and nitroethane; optionally, the nitroethane accounts for 15 vol% to 30 vol% in the solvent; optionally, the flash point of the solvent is not less than 62°C.

[0066] The present application provides a method for preparing the above-mentioned marine fuel oil detergent synergist, comprising heating a solvent to 40-60°C, adding an antioxidant and mixing evenly, then sequentially adding a lubricant and a core-shell dispersant and mixing evenly, then sequentially adding a sulfur scavenger and a pour point depressant, and mixing evenly using a high-pressure homogenizer at 40-52 MPa to obtain the marine fuel oil detergent synergist.

[0067] In some embodiments, the preparation method comprises the following steps:

[0068] S1 pre-mixing stage: heat the solvent to 45-50°C, add the antioxidant and stir to dissolve, then add the lubricant and stir at 45-50°C, 800-900 rpm for 30 minutes, then add the core-shell dispersant and stir at 55-60°C, 1200-1300 rpm for 1 hour;

[0069] S2 final mixing and homogenization stage: slowly add sulfur scavenger, disperse with the aid of 30-40kHz ultrasound for 30 minutes, then add pour point depressant and mix at 35-40℃ for 30 minutes, and finally circulate through a high-pressure homogenizer at 40-50MPa for 3 times.

[0070] In some embodiments, the method for preparing a sulfur scavenger comprises:

[0071] MgO modification: Nano-MgO (e.g., particle size 50 nm) and silane coupling agent KH-550 are mixed at a mass ratio of 100:1 and modified at 80°C for 2 hours.

[0072] Composite reaction stage: Zirconium nitrate solution was added dropwise to a modified MgO suspension (ethanol medium) at a molar ratio of Zr:Mg = 1:2. The reaction was maintained at 60°C for 2 hours. The pH was adjusted to 6.5 ± 0.2 with aqueous ammonia. After completion of the reaction, the suspension was centrifuged (8000 rpm, 10 minutes) and dried under vacuum at 80°C for 12 hours.

[0073] Alternatively, MgO modification: nano-MgO (50 nm) and KH-550 (mass ratio 100:1) were ultrasonically dispersed in ethanol for 30 minutes, and then modified under reflux at 80°C for 1.5 hours.

[0074] Composite reaction stage: Zirconium nitrate solution was slowly added dropwise to a modified MgO suspension (containing 0.1% polyvinylpyrrolidone dispersant) at a Zr:Mg ratio of 1:2. The reaction was performed at 60°C with ultrasound assistance (40 kHz) for 1.5 hours. The pH was then adjusted to 6.5 ± 0.2 with aqueous ammonia. After centrifugation (8000 rpm for 10 minutes), the mixture was vacuum-dried at 80°C for 10 hours.

[0075] Alternatively, MgO modification: nano-MgO (50 nm) and KH-550 (mass ratio 100:1) were pre-reacted in ethanol at 50 °C for 1 hour (to promote the adsorption of the coupling agent), and then the temperature was raised to 80 °C for modification for 1 hour (to complete the condensation reaction).

[0076] During the composite reaction phase, a zirconium nitrate solution and a modified MgO suspension (Zr:Mg = 1:2) were co-precipitated at 50°C. The pH was controlled to 6.5 ± 0.2 with aqueous ammonia. The mixture was then heated to 70°C and aged for 1 hour. The reaction solution was centrifuged (10,000 rpm, 8 minutes) and then step-dried (pre-dried at 60°C for 2 hours, then vacuum-dried at 80°C for 8 hours).

[0077] In some embodiments, the preparation method of the core-shell dispersant comprises:

[0078] PIBSI (polyisobutylene succinimide) core synthesis stage: Under nitrogen, PIBSA (molecular weight 950) and TEPA were added to a reactor at a molar ratio of 1:1.2. The reaction was heated at 120°C for 4 hours, with the acid value monitored until it reached ≤2 mgKOH / g. The product was purified by acetone precipitation three times and vacuum dried to a moisture content of ≤0.5%.

[0079] Polyetheramine grafting stage: PIBSI and ethylene oxide / propylene oxide copolymer (polyether polyol) (EO:PO=3:1, molecular weight 1000) are mixed in a mass ratio of 1:0.8 to 1:1.1, 0.1wt% dibutyltin dilaurate catalyst is added, and the mixture is reacted at 150-160°C for 3 hours. Finally, unreacted monomers are removed by thin film evaporation.

[0080] Alternatively, for core synthesis, PIBSA and TEPA (1:1.2 molar ratio) were pre-reacted at 100°C for 1 hour under nitrogen (to promote ring-opening), then heated to 130°C for 3 hours (condensation stage). The acid value was ≤ 2 mgKOH / g. The product was purified twice by ultrasound-assisted acetone precipitation (40 kHz, 20 minutes), and then dried in vacuo at 70°C to a moisture content of ≤ 0.3%.

[0081] Polyetheramine Grafting: PIBSI and EO / PO copolymer (1:1.1 mass ratio) were reacted in a staged reaction with 0.05 wt% stannous octoate as the catalyst: 140°C for 1 hour, followed by 160°C for 2 hours. After grafting, the product was purified by molecular distillation (180°C, 0.1 kPa) to a residual monomer content of <0.2%.

[0082] Alternatively, for core synthesis, PIBSA and TEPA (1:1.2 molar ratio) were reacted under nitrogen using a stepwise heating process: 80°C (0.5 hour, premixing) → 110°C (2 hours, amidation) → 125°C (1.5 hours, dehydration ring closure), with an acid value of ≤1.5 mgKOH / g. Purification was performed by precipitation twice with a 1:1 acetone / hexane mixture and vacuum drying at 60°C until the moisture content was ≤0.2%.

[0083] Polyetheramine Grafting: Optimized Catalytic System: 0.08wt% dibutyltin dilaurate + 0.02wt% p-toluenesulfonic acid combined catalyst. Gradient Grafting: PIBSI and EO / PO copolymer (1:1 mass ratio) were reacted at 140°C for 1 hour (to initiate grafting), 160°C for 2 hours (to complete chain extension), and finally devolatilized at 170°C for 0.5 hour. Two-stage thin-film evaporation (first stage, 120°C / 10kPa; second stage, 150°C / 0.5kPa) was used, resulting in a monomer residue of <0.1%.

[0084] Polyetheramine is a terminally aminated polymer obtained by amination reaction of ethylene oxide / propylene oxide copolymer (polyether polyol).

[0085] In some embodiments, the method for preparing a lubricant comprises:

[0086] Boric acid and glycerol were added to the reactor at a molar ratio of 1:3 to 1:3.5. The reaction was carried out at 150-160°C under nitrogen for 5-6 hours. Samples were taken every hour to test the boron content. After the reaction was completed, water was removed by vacuum distillation (-0.095 MPa, 80°C).

[0087] Alternatively, boric acid and glycerol (1:3 molar ratio) are mixed and then 0.5 wt% p-toluenesulfonic acid catalyst is added. The reaction is carried out at 140°C, and azeotropic dehydration with toluene (refluxing the oil-water separator) is performed, shortening the reaction time to 4 hours. Post-processing: Toluene is first removed by atmospheric distillation (110°C), followed by purification by reduced pressure distillation (-0.098 MPa, 70°C). Product specifications: esterification rate 88%-91%, residual moisture 0.3%-0.5%, and catalyst residue <200 ppm.

[0088] Alternatively, a gradient reaction is used: Stage 1: Premix boric acid and glycerol (1:3 molar ratio) at 120°C for 1 hour (to promote dissolution). Stage 2: Heat to 150°C and react for 3 hours while simultaneously introducing dry nitrogen (0.2 L / min) and connecting a 4A molecular sieve column for dynamic dehydration. Post-treatment: Two-stage vacuum distillation (first stage at -0.090 MPa / 60°C for light component removal, second stage at -0.100 MPa / 75°C for refining). Product specifications: Esterification rate 93%-95%, residual moisture ≤0.1%, and no risk of catalyst residue.

[0089] The present application provides a method for using the above-mentioned marine fuel oil detergent synergist, comprising: using the marine fuel oil as light diesel oil at a mass ratio of the detergent synergist to the light diesel oil of 1:1600 to 1:1400;

[0090] Alternatively, the marine fuel oil is low-sulfur fuel oil (LSFO, below 0.5%), and the mass ratio of detergent synergist to low-sulfur fuel oil is 1:1400 to 1:1200;

[0091] Alternatively, the marine fuel oil is high sulfur oil (HSFO, above 3.5%), and is used at a mass ratio of detergent synergist to high sulfur oil of 1:1200 to 1:1000.

[0092] The present application is further described below in conjunction with specific embodiments. The advantages and features of the present application will become clear as the description proceeds. The embodiments are merely exemplary and do not limit the scope of the present application in any way. It should be understood by those skilled in the art that the details and forms of the technical solutions of the present application may be modified or replaced without departing from the spirit and scope of the present application, and such modifications and replacements shall fall within the scope of protection of the present application.

[0093] All chemical reagents used in the examples of this application were of analytical grade and purchased from Sinopharm Group.

[0094] To make this application easier to understand, the following further describes this application in conjunction with specific examples. The experimental methods described in this application are all conventional methods unless otherwise specified; the biological materials described are all commercially available unless otherwise specified.

[0095] Example 1 Sulfur scavenger

[0096] Scheme 1: Conventional Modification Method - MgO Modification: Nano-MgO (particle size 50 nm) and silane coupling agent KH-550 were directly mixed in a mass ratio of 100:1 and mechanically stirred at 80°C for 2 hours. Composite Reaction Stage: Zirconium nitrate solution was added dropwise to the ethanol suspension of modified MgO at a molar ratio of Zr:Mg = 1:2. The reaction was continued at 60°C for 2 hours. The pH was adjusted to 6.5 ± 0.2 with aqueous ammonia. After the reaction, the mixture was centrifuged (8000 rpm for 10 minutes) and vacuum dried at 80°C for 12 hours.

[0097] Scheme 2: Ultrasonic-Assisted Modification - MgO Modification: Nano-MgO (50 nm) and KH-550 (mass ratio 100:1) were ultrasonically dispersed in ethanol for 30 minutes, followed by modification at 80°C under reflux for 1.5 hours. Composite Reaction Stage: Zirconium nitrate solution (Zr:Mg = 1:2 molar ratio) was slowly added dropwise to the modified MgO suspension (containing 0.1% polyvinylpyrrolidone dispersant). The reaction was ultrasonically assisted (40 kHz) at 60°C for 1.5 hours. The pH was then adjusted to 6.5 ± 0.2 with aqueous ammonia. After centrifugation (8000 rpm, 10 minutes), the mixture was vacuum-dried at 80°C for 10 hours.

[0098] Scheme 3: Gradient Temperature Ramp-Coprecipitation Method (Recommended Optimal Scheme) - MgO Modification: Nano-MgO (50nm) and KH-550 (mass ratio 100:1) were pre-reacted in ethanol at 50°C for 1 hour (to promote coupling agent adsorption), and then the temperature was raised to 80°C for modification for 1 hour (to complete the condensation reaction). Composite Reaction Stage: Zirconium nitrate solution and modified MgO suspension (Zr:Mg = 1:2) were co-precipitated at 50°C, the pH was controlled to 6.5±0.2 with ammonia water, and then the temperature was raised to 70°C for aging for 1 hour. The reaction solution was centrifuged (10,000 rpm, 8 minutes) and then step-dried (pre-dried at 60°C for 2 hours, then vacuum-dried at 80°C for 8 hours).

[0099] The gradient temperature method promotes the hydrolysis and condensation of the silane coupling agent in stages, increasing the grafting rate by 15% to 20% compared to the conventional method (Scheme 1). The product of Scheme 3 achieved an adsorption capacity of 85 mg / g in a sulfur capacity test at 200°C, a significant improvement over Scheme 1 (68 mg / g) and Scheme 2 (62 mg / g).

[0100] Example 2 Core-shell dispersant

[0101] Scheme 1: Conventional Synthesis - Core Synthesis: Under nitrogen, add PIBSA (molecular weight 950) and TEPA in a molar ratio of 1:1.2 to a reactor. React at 120°C for 4 hours, monitoring the acid value to ≤2 mgKOH / g. Purify the product by acetone precipitation three times and vacuum dry at 80°C to a moisture content of ≤0.5%. Polyetheramine Grafting: PIBSI and an EO / PO copolymer (EO:PO = 3:1, molecular weight 1000) were mixed in a 1:1 mass ratio. 0.1 wt% dibutyltin dilaurate was added and the mixture was reacted at 150°C for 3 hours. Unreacted monomers were removed by thin-film evaporation.

[0102] Scheme 2: Staged Temperature Control-Ultrasound-Assisted Nucleus Synthesis: Under nitrogen, PIBSA and TEPA (1:1.2 molar ratio) were pre-reacted at 100°C for 1 hour (to promote ring-opening), then heated to 130°C for 3 hours (condensation stage), with an acid value of ≤2 mgKOH / g. Purification was performed twice using ultrasound-assisted acetone precipitation (40 kHz, 20 minutes), followed by vacuum drying at 70°C to a moisture content of ≤0.3%. Polyetheramine Grafting: PIBSI and EO / PO copolymer (1:1.1 mass ratio) were catalyzed by 0.05 wt% stannous octoate in a staged reaction: 140°C for 1 hour, followed by 160°C for 2 hours. After grafting, purification was achieved by molecular distillation (180°C, 0.1 kPa), with a residual monomer content of <0.2%.

[0103] Scheme 3: Catalytic Optimization - Gradient Grafting Method (Recommended Optimal Scheme) - Core Synthesis: PIBSA and TEPA (1:1.2 molar ratio) were reacted under nitrogen using a stepwise temperature ramp: 80°C (0.5 hour, premixing) → 110°C (2 hours, amidation) → 125°C (1.5 hours, dehydration and ring closure). Acid value ≤ 1.5 mgKOH / g. Purification was performed using two precipitations with a 1:1 acetone / n-hexane mixed solvent and vacuum drying at 60°C to a moisture content ≤ 0.2%. Polyetheramine Grafting: Catalytic System Optimization: 0.08 wt% dibutyltin dilaurate + 0.02 wt% p-toluenesulfonic acid combined catalyst. Gradient Grafting: PIBSI and EO / PO copolymer (1:1 mass ratio) were reacted at 140°C for 1 hour (grafting initiation), 160°C for 2 hours (chain extension completion), and finally devolatilized at 170°C for 0.5 hour. Two-stage thin film evaporation (first stage 120°C / 10kPa, second stage 150°C / 0.5kPa), monomer residue <0.1%.

[0104] Scheme 3, through step-by-step temperature control and composite catalysis, balances reaction rate and side reaction suppression, making it more suitable for scale-up. Dispersion performance tests show that the diesel detergency (nozzle deposits) of the product of Scheme 3 is 15% lower than that of Scheme 1. The catalytic optimization-gradient grafting method (Scheme 3) offers the best performance in terms of reaction control, product purity, and application performance, and is recommended as the preferred option for industrial production.

[0105] Example 3 Lubricant

[0106] Option 1: Conventional Esterification Method - Esterification reaction: Boric acid and glycerol are added to a reactor in a molar ratio of 1:3. The reaction is carried out at 160°C under nitrogen for 6 hours. Samples are taken every hour to determine the boron content (titration). Post-treatment: After the reaction is completed, water is removed by vacuum distillation at -0.095 MPa and 80°C for 2 hours. Product specifications: Esterification rate 82%-85%, residual moisture 0.8%-1.2%.

[0107] Option 2: Catalytic Esterification - Boric acid and glycerol (1:3 molar ratio) are mixed, and 0.5 wt% p-toluenesulfonic acid catalyst is added. The reaction is carried out at 140°C, and azeotropic dehydration with toluene (oil-water separator reflux) is performed, shortening the reaction time to 4 hours. Post-treatment: Toluene is first removed by atmospheric distillation (110°C), followed by purification by reduced pressure distillation (-0.098 MPa, 70°C). Product specifications: Esterification rate 88%-91%, residual moisture 0.3%-0.5%, and catalyst residue <200 ppm.

[0108] Option 3: Gradient Temperature Ramp-Zeolite Dehydration Method (Recommended Optimal Option) - Gradient Reaction: Stage 1: Premix boric acid and glycerol (1:3 molar ratio) at 120°C for 1 hour (to promote dissolution). Stage 2: Raise the temperature to 150°C and react for 3 hours, while simultaneously introducing dry nitrogen (0.2 L / min) and connecting a 4A molecular sieve column in series for dynamic dehydration. Post-treatment: Two-stage vacuum distillation (first stage at -0.090 MPa / 60°C for light component removal, second stage at -0.100 MPa / 75°C for refining). Product specifications: Esterification rate 93%-95%, residual moisture ≤0.1%, no risk of catalyst residue.

[0109] Dynamic dehydration of molecular sieves increases the esterification rate to 95% (more than 10% higher than that of solution 1).

[0110] Example 4 Marine Fuel Oil Detergent and Synergist

[0111] Preparation of synergists with different ratios: Adjust the ratio of each component (sulfur scavenger, core-shell dispersant, lubricant, antioxidant, pour point depressant, solvent) and investigate its effect on the performance.

[0112] Example ratio range:

[0113] Sulfur scavenger: 8% to 12% (Zr-Mg complex, sulfur adsorption ≥ 15 mg S / g); core-shell dispersant: 15% to 20% (PIBSI-polyetheramine core-shell crosslinked product, thermal weight loss at 300°C ≤ 5%); lubricant: 5% to 8% (boronated glycerol ester, boron content 3.5% to 4.0%); antioxidant: 0.5% to 1% (alkylated diphenylamine, oxidation induction period ≥ 120 minutes at 150°C); pour point depressant: 1% to 2% (polymethacrylate, pour point depression ≥ 15°C); solvent: balance (hydrogenated terphenyl + 15% to 30% nitroethane, flash point ≥ 62°C)

[0114] Performance test indicators

[0115] Flash point: ensure solvent safety (≥62°C); Sulfur suppression efficiency: evaluated by the adsorption capacity of the sulfur scavenger (≥15mgS / g); Combustion efficiency: test the soot emission reduction rate and the change in combustion calorific value; Atomization performance: the effect of the core-shell dispersant on the uniformity of fuel atomization; Antioxidant properties: the oxidation induction period of the antioxidant at high temperature (150°C) (≥120min); Anti-wear properties: the protective effect of the lubricant (boronated glycerol ester) on engine components.

[0116] Example Design

[0117] Option 1 (low sulfur oil):

[0118] The sulfur scavenger of Scheme 3 of Example 1 (10%), the core-shell dispersant of Scheme 3 of Example 2 (18%), the lubricant of Scheme 3 of Example 3 (6%), alkylated diphenylamine (0.8%), polymethacrylate (1.5%), and the balance (70 vol% hydrogenated terphenyl and 30 vol% nitroethane) are used. Low-sulfur fuel oil (LSFO, 0.5%) is suitable, with an addition ratio of 1:1400.

[0119] Option 2 (high sulfur oil):

[0120] The sulfur scavenger of Scheme 3 of Example 1 (12%), the core-shell dispersant of Scheme 3 of Example 2 (20%), the lubricant of Scheme 3 of Example 3 (5%), alkylated diphenylamine (1%), polymethacrylate (2%), and the balance (70 vol% hydrogenated terphenyl and 30 vol% nitroethane). High-sulfur fuel oil (HSFO, 3.5% sulfur) is suitable, with an addition ratio of 1:1000.

[0121] Option 3 (light diesel):

[0122] 8% sulfur scavenger from Scheme 3 of Example 1, 15% core-shell dispersant from Scheme 3 of Example 2, 8% lubricant from Scheme 3 of Example 3, 0.5% alkylated diphenylamine, 1% polymethacrylate, and the balance being 70% hydrogenated terphenyl and 30% nitroethane. Suitable for light diesel fuel, the addition ratio is 1:1600.

[0123] Option 4 (low sulfur oil):

[0124] The sulfur scavenger of Scheme 1 of Example 1 (10%), the core-shell dispersant of Scheme 1 of Example 2 (18%), the lubricant of Scheme 1 of Example 3 (6%), alkylated diphenylamine (0.8%), polymethacrylate (1.5%), and the balance (70 vol% hydrogenated terphenyl and 30 vol% nitroethane) are used. Low-sulfur fuel oil (LSFO, 0.5% sulfur) is used, with an addition ratio of 1:1400.

[0125] Option 5 (low sulfur oil):

[0126] The sulfur scavenger of Scheme 2 of Example 1 (10%), the core-shell dispersant of Scheme 2 of Example 2 (18%), the lubricant of Scheme 2 of Example 3 (6%), alkylated diphenylamine (0.8%), polymethacrylate (1.5%), and the balance (70 vol% hydrogenated terphenyl and 30 vol% nitroethane) are used. Low-sulfur fuel oil (LSFO, 0.5%) is suitable, with an addition ratio of 1:1400.

[0127] Preparation process of Scheme 1 to Scheme 5:

[0128] S1 pre-mixing stage: heat the solvent to 45-50°C, add the antioxidant and stir to dissolve, then add the lubricant and stir at 45-50°C, 800-900 rpm for 30 minutes, then add the core-shell dispersant and stir at 55-60°C, 1200-1300 rpm for 1 hour;

[0129] S2 final mixing and homogenization stage: slowly add sulfur scavenger, disperse with the aid of 30-40kHz ultrasound for 30 minutes, then add pour point depressant and mix at 35-40℃ for 30 minutes, and finally circulate through a high-pressure homogenizer at 40-50MPa for 3 times.

[0130] Performance test results:

[0131] Recommended preferred solution

[0132] Formula: 10% sulfur scavenger, 18% core-shell dispersant, 6% lubricant, 0.8% antioxidant, 1.5% pour point depressant. Balanced sulfur suppression (15mg S / g), dispersion stability (core-shell structure thermal weight loss ≤ 5%), and cost-effectiveness, suitable for mainstream sulfur fuels (0.5% to 3.5%).

[0133] Unless otherwise defined, all technical and scientific terms used in this application are the same as those commonly understood by those skilled in the art to which this application belongs. In the event of any inconsistency, the meaning described in the full text of this application or the meaning derived from the content recorded in the full text of this application shall prevail. In addition, the terms used in this description are only for the purpose of describing the embodiments of the present application and are not intended to limit this application.

[0134] The term "comprising" used throughout this application should not be interpreted as limiting the contents listed thereafter; it does not exclude other structural elements or steps. Therefore, it should be interpreted as specifying the presence of the technical features, integers, steps or components mentioned, but does not exclude the presence or addition of one or more other technical features, integers, steps or components and groups thereof.

[0135] It can be understood that those skilled in the art can combine the features mentioned in one or more embodiments mentioned throughout the present application with the features of other embodiments in any appropriate manner to implement the present application.

Claims

1. A marine fuel oil detergent synergist, characterized in that: The marine fuel oil detergent synergist comprises the following components by mass percentage: 8% to 12% sulfur scavenger, 15% to 20% core-shell dispersant, 5% to 8% lubricant, 0.5% to 1% antioxidant and 1% to 2% pour point depressant, with the balance being solvent; The sulfur capture agent is a Zr-Mg complex, which achieves sulfur selective adsorption through the Zr-O-Mg active site; The core-shell dispersant is a PIBSI-polyetheramine core-shell crosslinked compound, wherein PIBSI is the core and polyetheramine is the shell; The lubricant is boronated glyceride.

2. The marine fuel oil detergent synergist according to claim 1, characterized in that: The sulfur capture agent is Zr 4+ -MgO complex, optionally, the sulfur capture agent is a Zr(NO3)4-MgO complex; Optionally, the sulfur scavenger has a sulfur adsorption capacity of not less than 15 mg S / g; Optionally, the PIBSI-polyetheramine core-shell crosslinked product has a thermal weight loss of no more than 5% under high temperature conditions of 300°C; Optionally, the boron content of the boronated glyceride is in the range of 3.5 wt% to 4.0 wt%.

3. The marine fuel oil detergent synergist according to claim 1, characterized in that: The antioxidant is alkylated diphenylamine; Optionally, the antioxidant has an oxidation induction period of not less than 120 minutes at 150°C; Optionally, the pour point depressant is polymethacrylate with a molecular weight of 8000; Optionally, the pour point depressant reduces the pour point of the fuel oil by more than 15°C.

4. The marine fuel oil detergent synergist according to any one of claims 1 to 3, characterized in that: The solvent is a mixed solution of hydrogenated terphenyl and nitroethane; Optionally, the nitroethane accounts for 15 vol% to 30 vol% in the solvent; Optionally, the flash point of the solvent is not lower than 62°C.

5. The method for preparing the marine fuel oil detergent synergist according to any one of claims 1 to 4, characterized in that: The solvent is heated to 40-60° C., an antioxidant is added and mixed, a lubricant and a core-shell dispersant are subsequently added and mixed, a sulfur scavenger and a pour point depressant are then added and mixed using a high-pressure homogenizer at 40-52 MPa to obtain the marine fuel oil detergent synergist.

6. The preparation method according to claim 5, characterized in that The preparation method comprises the following steps: S1 pre-mixing stage: heat the solvent to 45-50°C, add the antioxidant and stir to dissolve, then add the lubricant and stir at 45-50°C, 800-900 rpm for 30 minutes, then add the core-shell dispersant and stir at 55-60°C, 1200-1300 rpm for 1 hour; S2 final mixing and homogenization stage: slowly add sulfur scavenger, disperse with the aid of 30-40kHz ultrasound for 30 minutes, then add pour point depressant and mix at 35-40℃ for 30 minutes, and finally circulate through a high-pressure homogenizer at 40-50MPa for 3 times.

7. The preparation method according to claim 5 or 6, characterized in that: Under the condition of pH 6.3-6.7, the modified nano-MgO reacts with zirconium nitrate, and the sulfur capture agent is obtained by separation and drying. Optionally, the composite reaction is carried out at 50-70° C. for 1.5-2.5 hours, and the molar ratio of Zr to Mg is 1:2-1:3; Optionally, the modifier of nano-MgO is silane coupling agent KH-550; Optionally, the modification condition is 50-80° C. for 1.5-2.5 hours; Optionally, the particle size of nano-MgO is 50-70 nm.

8. The preparation method according to claim 5 or 6, characterized in that: The preparation method of the core-shell dispersant comprises: (a) PIBSI core synthesis stage: PIBSA is reacted with polyamines under inert gas conditions with an acid value not exceeding 2 mg KOH / g, and then dried to obtain the PIBSI core; (b) polyetheramine grafting stage: the PIBSI core in (a) is reacted with polyetheramine in the presence of a catalyst, and unreacted monomers are removed to obtain a core-shell dispersant; Optionally, the polyamine in (a) is TEPA, the reaction conditions are 80-130° C. for 3-4 hours, and the moisture content of the PIBSI core is ≤0.5%; Optionally, the catalyst in (b) is at least one of 0.08 wt% to 0.1 wt% of dibutyltin dilaurate, 0.05 wt% of stannous octoate and 0.02 wt% of p-toluenesulfonic acid, and the reaction conditions are 140-170° C. for 3-4 hours.

9. The preparation method according to claim 5 or 6, characterized in that: Boric acid and glycerol are reacted at a molar ratio of 1:3 to 1:3.5 at 120 to 160° C. under nitrogen protection for 5 to 6 hours to obtain the lubricant.

10. The method for using the marine fuel oil detergent synergist according to any one of claims 1 to 4, characterized in that: The method of use includes: using light diesel as the marine fuel oil, and using the detergent synergist to light diesel at a mass ratio of 1:1600 to 1:1400; Alternatively, the marine fuel oil is low-sulfur fuel oil (LSFO, below 0.5%), and the mass ratio of detergent synergist to low-sulfur fuel oil is 1:1400 to 1:1200; Alternatively, the marine fuel oil is high sulfur oil (HSFO, above 3.5%), and is used at a mass ratio of detergent synergist to high sulfur oil of 1:1200 to 1:1000.

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