A method for preparing liquid wax alcohol ether composite diesel engine fuel

Abstract

The invention relates to the technical field of new energy and fuel, and discloses a preparation method of a liquid wax alcohol ether composite diesel engine fuel. The raw materials and their weight ratio range are: diesel 8%-13%; liquid wax 9%-15%; soybean oil 17%-23%; polyethylene glycol ether 20%-27%; aromatic alcohol polyoxyethylene ether 14%-18%; oxidant 1.2%-1.9%; metal passivator 0.3%-0.8%; low temperature fluidity improver 1.1%-1.3%; pour point depressant 0.08%-0.15%; composite emulsifier 3.3% to 4.0%; alkaline zeolite catalyst 2.5% to 3.0%, prepare the above raw materials according to the weight ratio of the formula, and perform pretreatment, mix the pretreated soybean oil, diesel, polyethylene glycol ether and liquid wax in A and B stirring tanks, and then introduce them into C stirring tank together, add alkaline zeolite catalyst into C stirring tank for reaction, add additives in sequence to obtain a mixture, use supercritical fluid technology to extract and separate the mixture to obtain diesel engine fuel, implement a closed-loop production system for the whole process, and recycle the waste.

Description

Technical Field

[0001] The invention relates to the technical field of new energy and fuel, and in particular to a method for preparing a liquid wax alcohol ether composite diesel engine fuel. Background Art

[0002] In today’s energy landscape, conventional fuel formulations face multiple challenges. While these fuels have historically provided a reliable source of power for industry and transportation, they often struggle with both oxidation stability and low-temperature performance. Oxidation stability is a measure of a fuel’s ability to resist oxidative deterioration during storage and use, while low-temperature performance is about the fuel’s fluidity and reliability in cold environments. Unfortunately, conventional fuel preparation methods often fail to meet both of these critical requirements, resulting in reduced or unstable fuel performance in real-world applications.

[0003] In addition, the production process of traditional fuels is often accompanied by the generation of waste. If these wastes are not properly handled, they will cause serious pollution to the environment. For example, the waste gas, wastewater and solid waste generated in the fuel production process, if not properly purified and recycled, will be released into the natural environment, which will have a negative impact on air quality, water resources and soil quality. Therefore, the development of new fuels and their preparation technologies to solve the contradiction between oxidation stability and low-temperature performance and reduce environmental impact has become an urgent problem to be solved in the energy industry. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the shortcomings of the prior art, the present invention provides a method for preparing a liquid wax alcohol ether composite diesel engine fuel, which is environmentally friendly and the produced fuel has the advantages of both oxidation stability and low temperature performance, thereby solving the problem that waste is easily generated in the traditional preparation method and the produced fuel cannot take into account both oxidation stability and low temperature performance at the same time.

[0006] (II) Technical solution

[0007] To achieve the above object, the present invention provides the following technical solution: a method for preparing a liquid wax alcohol ether composite diesel engine fuel, comprising the following steps:

[0008] Step 1, prepare raw materials: prepare diesel, liquid wax, soybean oil, polyethylene glycol ether, aromatic alcohol polyoxyethylene ether, oxidant, metal passivator, low temperature fluidity improver, pour point depressant, composite emulsifier and alkaline zeolite catalyst with formula proportion;

[0009] Step 2: Raw material pretreatment: Dehydrate and filter the diesel, and heat the liquid wax and soybean oil at 40-45°C respectively;

[0010] Step 3, mixing: mix the pretreated soybean oil, diesel and polyethylene glycol ether, stir evenly in mixing tank A, the mixing time is 5-7 minutes, mix the pretreated liquid wax and aromatic alcohol polyoxyethylene ether in mixing tank B, stir evenly, the mixing time is 6-9 minutes;

[0011] Step 4: Adding alkaline zeolite catalyst for reaction: connecting the mixtures in stirring tanks A and B to stirring tank C through pipes at both ends, stirring evenly in stirring tank C, and adding alkaline zeolite catalyst during the stirring process. The stirring time is 12-15 minutes, and nitrogen with a concentration of more than 99% is introduced during the reaction;

[0012] Step 5, adding additives: maintaining the reaction temperature, sequentially adding a composite emulsifier, an oxidant, a metal passivator, a pour point depressant and a low-temperature fluidity improver to the C stirring tank and stirring for 8-12 minutes to obtain a mixture;

[0013] Step 6: Filtration and purification: Use supercritical fluid technology to extract and separate the mixture, and finally obtain diesel fuel;

[0014] Step 7. Waste treatment and recycling: A closed-loop production system is implemented throughout the entire process from step 1 to step 6 to recycle the waste generated during the production process.

[0015] Preferably, the raw materials and their weight ratio range are: diesel 8% to 13%; liquid wax 9% to 15%; soybean oil 17% to 23%; polyethylene glycol ether 20% to 27%; aromatic alcohol polyoxyethylene ether 14% to 18%; oxidant 1.2% to 1.9%; metal passivator 0.3% to 0.8%; low temperature fluidity improver 1.1% to 1.3%; pour point depressant 0.08% to 0.15%; composite emulsifier 3.3% to 4.0%; alkaline zeolite catalyst 2.5% to 3.0%.

[0016] Preferably, the raw materials and their weight ratio are: 8% diesel; 9% liquid wax; 23% soybean oil; 27% polyethylene glycol ether; 14% aromatic alcohol polyoxyethylene ether; 1.9% oxidant; 0.3% metal passivator; 1.5% low temperature fluidity improver; 0.095% pour point depressant; 3.6% composite emulsifier; and 2.98% alkaline zeolite catalyst.

[0017] Preferably, the raw materials and their weight ratio are: diesel 12%; liquid wax 11%; soybean oil 19%; polyethylene glycol ether 21%; aromatic alcohol polyoxyethylene ether 15%; oxidant 1.6%; metal passivator 0.4%; low temperature fluidity improver 1.23%; pour point depressant 0.085%; composite emulsifier 3.67%; alkaline zeolite catalyst 2.6%.

[0018] Preferably, the oxidant consists of butylated hydroxyanisole and octaphenylpropoxyphosphine in a ratio of 1:1.

[0019] Preferably, the metal passivator is phytic acid, and the low-temperature fluidity improver is selected from one of a glycerol ether derivative, an amidate adjuvant and an ozonated vegetable oil.

[0020] Preferably, the pour point depressant consists of a 3:2:2 ethylene-vinyl acetate copolymer, petroleum sulfate and a benzene-containing terpolymer.

[0021] Preferably, the composite emulsifier consists of n-butanol, oleic acid and ferrocene in a ratio of 1:2:1.

[0022] Preferably, the reaction conditions for adding the alkaline zeolite catalyst in step 4 are: the pressure is controlled between 1.5 and 2.0 times the standard atmospheric pressure, and the temperature is controlled between -5°C and 30°C.

[0023] Preferably, the filtering and refining process in step six is:

[0024] S6.1. Coarse filtration: The mixture is filtered through a plate and frame filter with a pore size of 50 to 100 microns. The flow rate is controlled at 1.5 to 2.5 m / s. 3 / h;

[0025] S6.2, Supercritical fluid extraction: Use carbon dioxide as the supercritical fluid, control the temperature at 35-40℃, and the pressure at 7.5-8MPa, and put the coarsely filtered mixture into a supercritical fluid extractor to make CO 2 The fluid is fully in contact with the mixture, and the residence time is controlled at 45 to 50 minutes before entering the separator;

[0026] S6.3, Separation and collection: In the separator, the pressure is reduced to 3.5-4 MPa and the temperature is increased to 50-55°C. 2 The fuel precipitates out of the fluid and condenses at the bottom of the separator, where it is collected through a valve;

[0027] S6.4, Refining treatment: Use hydrodesulfurization method to reduce the sulfide content in the fuel to below 0.05%, add 10ml of 5% sodium carbonate solution to reduce the acid value to below 0.01mgKOH / g, and reduce the water content of the fuel to below 0.05% by vacuum drying. Finally, use a fine filter with a filter element pore size of 2 to 3 microns to perform final filtration on the fuel to obtain high-purity diesel fuel.

[0028] Compared with the prior art, the present invention provides a method for preparing a liquid wax alcohol ether composite diesel engine fuel, which has the following beneficial effects:

[0029] 1. The present invention optimizes the formula ratio and adds soybean oil and alkaline zeolite catalyst in the formula ratio, wherein the addition of soybean oil can not only effectively reduce the sulfur content and acid value in the fuel, reduce the pollutant emissions during the combustion process, and reduce the pollution to the environment, but also reduce the corrosiveness of the fuel to the engine parts, thereby extending the service life of the engine. As a renewable resource, soybean oil can improve the renewability of the fuel, help reduce the dependence on fossil fuels, and achieve sustainable development of energy; at the same time, soybean oil and other ingredients can also improve the lubricity of the fuel and reduce the wear of the engine parts. Reasonably control the proportion of each component so that the kinematic viscosity of the fuel is in a moderate range, which is conducive to the injection and combustion of the fuel, and the alkaline zeolite catalyst can promote the reaction between the fuel components and improve the purity of the fuel.

[0030] 2. The present invention applies supercritical fluid extraction technology, which can effectively separate different components in the fuel and ensure sufficient contact and separation, thereby further improving the purity of the fuel. Its operating temperature is relatively low, which is conducive to maintaining the stability of the fuel. At the same time, under high pressure conditions, it helps to better dissolve the components. The hydrodesulfurization method and sodium carbonate solution treatment are used to accurately control the sulfur content and acid value in the fuel, which can improve the environmental performance and corrosion resistance of the fuel. Through vacuum drying and fine filtration, the dryness and cleanliness of the fuel are ensured, further ensuring the quality of the fuel, making it safer and more reliable during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart was prepared for the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See also Figure 1 , a method for preparing a liquid wax alcohol ether composite diesel engine fuel, comprising the following steps:

[0034] Step 1. Prepare raw materials: prepare diesel, liquid wax, soybean oil, polyethylene glycol ether, aromatic alcohol polyoxyethylene ether, oxidant, metal passivator, low temperature fluidity improver, pour point depressant, composite emulsifier and alkaline zeolite catalyst with a certain proportion of the formula. Using renewable resources such as soybean oil as one of the raw materials will help reduce dependence on fossil fuels and reduce environmental pollution.

[0035] Step 2: Raw material pretreatment: Dehydrate and filter the diesel to remove impurities and moisture, heat the liquid wax and soybean oil at 40-45°C to effectively reduce their viscosity and increase their fusion, so that different components can be more fully fused in the subsequent mixing process, which helps to improve the mixing efficiency;

[0036] Step 3, mixing: the pretreated soybean oil, diesel and polyethylene glycol ether are mixed, and the mixture is stirred evenly in a stirring tank A for 5-7 minutes. The pretreated liquid wax is mixed with aromatic alcohol polyoxyethylene ether, and the mixture is stirred evenly in a stirring tank B for 6-9 minutes. The mixing operation is carried out in steps, which is conducive to controlling the temperature and time during the mixing process, ensuring that the components are fully mixed and evenly mixed. By setting a reasonable stirring time (5-7 minutes for tank A and 6-9 minutes for tank B), the mixture reaches a uniform state, providing a good foundation for subsequent reactions;

[0037] Step 4, adding alkaline zeolite catalyst to react: connect the mixtures of A and B stirring tanks to C stirring tank through pipes at both ends, stir evenly in C stirring tank, and add alkaline zeolite catalyst during stirring. Alkaline zeolite catalyst has good catalytic activity and selectivity, can effectively promote the reaction between the mixtures of A and B stirring tanks, improve reaction rate and conversion rate, stirring time is 12-15min, and nitrogen with a concentration of more than 99% is introduced during the reaction. During the reaction, nitrogen with a concentration of more than 99% is introduced to form an inert gas atmosphere, which can prevent the mixture from reacting adversely with oxygen in the air and protect the smooth progress of the reaction;

[0038] Step 5, adding additives: maintaining the reaction temperature, adding composite emulsifier, oxidant, metal passivator, pour point depressant and low temperature fluidity improver to the C stirring tank in sequence and stirring, adding composite emulsifier, oxidant, metal passivator, pour point depressant and low temperature fluidity improver and other additives in sequence, can improve the emulsification performance, oxidation stability, metal corrosion, low temperature fluidity and pour point of the fuel in a targeted manner, and improve the overall quality of the fuel, stirring for 8-12 minutes to obtain a mixture, ensuring that the additives are fully dispersed in the mixture, evenly combined with each component, and play the best performance improvement role;

[0039] Step 6, filtration and purification: Use supercritical fluid technology to extract and separate the mixture. Using supercritical fluid technology for extraction and separation has the characteristics of high selectivity and high efficiency, and can effectively remove impurities and unnecessary components in the mixture, improve the purity and performance of the fuel, and finally obtain diesel fuel, thereby effectively reducing the use of traditional solvents, reducing the cost of solvent recovery and treatment, and reducing the generation of waste, meeting the requirements of environmental protection and energy saving;

[0040] Step 7. Waste treatment and recycling: A closed-loop production system is implemented throughout the entire process from step 1 to step 6, thereby reducing waste emissions and effectively reducing the impact on the environment. Waste generated during the production process is recycled, which can achieve the circular utilization of resources, help improve the resource utilization efficiency of the production process, and reduce production costs.

[0041] Specifically, the raw materials and their weight ratio range are: diesel 8% to 13%; liquid wax 9% to 15%; soybean oil 17% to 23%; polyethylene glycol ether 20% to 27%; aromatic alcohol polyoxyethylene ether 14% to 18%; oxidant 1.2% to 1.9%; metal passivator 0.3% to 0.8%; low-temperature fluidity improver 1.1% to 1.3%; pour point depressant 0.08% to 0.15%; composite emulsifier 3.3% to 4.0%; alkaline zeolite catalyst 2.5% to 3.0%.

[0042] Specifically, the oxidant is composed of butylated hydroxyanisole and octaphenyl propoxy phosphine in a ratio of 1:1.

[0043] Specifically, the metal passivator is phytic acid, and the low-temperature fluidity improver is selected from one of a glycerol ether derivative, an amide auxiliary agent and an ozonated vegetable oil.

[0044] Specifically, the pour point depressant is composed of a 3:2:2 ethylene-vinyl acetate copolymer, petroleum sulfate and a benzene-containing terpolymer.

[0045] Specifically, the composite emulsifier is composed of n-butanol, oleic acid and ferrocene in a ratio of 1:2:1.

[0046] Specifically, the reaction conditions for adding the alkaline zeolite catalyst in step 4 are: the pressure is controlled between 1.5 and 2.0 times the standard atmospheric pressure, and the temperature is controlled between -5°C and 30°C.

[0047] Specifically, the filtering and refining process in step six is:

[0048] S6.1. Coarse filtration: The mixture is filtered through a plate and frame filter with a pore size of 50 to 100 microns. The flow rate is controlled at 1.5 to 2.5 m / s. 3 / h to avoid incomplete filtration due to too fast flow rate;

[0049] S6.2, Supercritical fluid extraction: Carbon dioxide is selected as the supercritical fluid, compressed to a supercritical state by a high-pressure pump, the temperature is controlled at 35-40°C, the pressure is controlled at 7.5-8MPa, and the coarsely filtered mixture is placed in a supercritical fluid extractor to make CO 2 The fluid is fully in contact with the mixture, and the residence time is controlled at 45 to 50 minutes. Under the supercritical state, CO 2The fluid dissolves the target components and carries them out of the extractor, then enters the separator, where the high solubility of the supercritical fluid is used to separate the fuel from the impurities in the mixture, thereby improving the purity and performance of the fuel;

[0050] S6.3, Separation and collection: In the separator, the pressure is reduced to 3.5-4 MPa and the temperature is increased to 50-55°C to reduce the density of the CO2 fluid and weaken its solubility. 2 The fuel, CO 2 The fluid is discharged through the vent valve and can be recycled after cooling and compression. The target components in the extract are separated from the supercritical fluid and high-purity fuel components are collected.

[0051] S6.4, Refining treatment: Use hydrodesulfurization method to reduce the sulfide content in the fuel to below 0.05%, add 10ml of 5% sodium carbonate solution to neutralize the acidic substances in the fuel and reduce the acid value to below 0.01mgKOH / g, remove the moisture in the fuel by vacuum drying, and reduce the water content of the fuel to less than 0.05%, and finally use a fine filter with a filter element pore size of 2 to 3 microns to perform final filtration on the fuel to obtain high-purity diesel fuel, remove tiny particle impurities, ensure the cleanliness of the fuel, and further refine the collected target components to improve the performance indicators of the fuel, such as reducing sulfur content and acid value.

[0052] Example 1

[0053] Specifically, the raw materials and their weight ratio are: 8% diesel; 9% liquid wax; 23% soybean oil; 27% polyethylene glycol ether; 14% aromatic alcohol polyoxyethylene ether; 1.9% oxidant; 0.3% metal passivator; 1.5% low-temperature fluidity improver; 0.095% pour point depressant; 3.6% composite emulsifier; and 2.98% alkaline zeolite catalyst, and the preparation method of the present invention is used for preparation.

[0054] Example 2

[0055] Specifically, the raw materials and their weight ratio are: 12% diesel; 11% liquid wax; 19% soybean oil; 21% polyethylene glycol ether; 15% aromatic alcohol polyoxyethylene ether; 1.6% oxidant; 0.4% metal passivator; 1.23% low-temperature fluidity improver; 0.085% pour point depressant; 3.67% composite emulsifier; and 2.6% alkaline zeolite catalyst, and are prepared using the preparation method of the present invention.

[0056] Example 3

[0057] The raw material formula of the present invention is used for preparation, and the filtering and refining process in the preparation method is as follows:

[0058] S6.1. Coarse filtration: The mixture is filtered through a plate and frame filter with a pore size of 50 to 100 microns. The flow rate is controlled at 1.5 to 2.5 m / s. 3 / h;

[0059] S6.2, Supercritical fluid extraction: Use carbon dioxide as the supercritical fluid, control the temperature at 35-40℃, and the pressure at 7.5-8MPa, and put the coarsely filtered mixture into a supercritical fluid extractor to make CO 2 The fluid is fully in contact with the mixture, and the residence time is controlled at 45 to 50 minutes before entering the separator;

[0060] S6.3, Separation and collection: In the separator, the pressure is reduced to 3.5-4 MPa and the temperature is increased to 50-55°C. 2 The fuel precipitates out of the fluid and condenses at the bottom of the separator, where it is collected through a valve;

[0061] S6.4, Refining treatment: Use hydrodesulfurization method to reduce the sulfide content in the fuel to below 0.05%, add 10ml of 5% sodium carbonate solution to reduce the acid value to below 0.01mgKOH / g, and reduce the water content of the fuel to below 0.05% by vacuum drying. Finally, use a fine filter with a filter element pore size of 2 to 3 microns to perform final filtration on the fuel to obtain high-purity diesel fuel.

[0062] Comparative Example 1

[0063] Specifically, the raw materials and their weight ratio are: 38% diesel; 9% liquid wax; 27% polyethylene glycol ether; 14% aromatic alcohol polyoxyethylene ether; 1.9% oxidant; 0.3% metal passivator; 1.5% low temperature fluidity improver; 0.095% pour point depressant; 3.6% composite emulsifier; 2.98% alkaline zeolite catalyst, and are prepared using the preparation method of the present invention (increasing the diesel content in Example 1 and deleting the soybean oil component).

[0064] Comparative Example 2

[0065] Specifically, the raw materials and their weight ratio are: diesel 12%; liquid wax 11%; soybean oil 19%; polyethylene glycol ether 21%; aromatic alcohol polyoxyethylene ether 15%; oxidant 1.6%; metal passivator 0.4%; low-temperature fluidity improver 1.23%; pour point depressant 0.085%; composite emulsifier 3.67%, and the preparation method of the present invention is used for preparation (the alkaline zeolite catalyst in Example 2 is removed).

[0066] Comparative Example 3

[0067] The raw material formula of the present invention is used for preparation, and the filtering and refining process is carried out by the traditional method as follows:

[0068] T6.1. Preliminary filtration: After the preparation of polyols is completed, the mixed solution needs to be initially filtered;

[0069] T6.2, Ceramic membrane filtration: After the preliminary filtration, the mixed liquid will be further filtered and impurities will be removed using a ceramic membrane with a pore size greater than 50nm to obtain a mixed liquid;

[0070] T6.3. Standing sedimentation: After stirring the mixed liquid, let it stand for 1-2 hours to allow the flocs at the bottom to settle. Finally, take the upper clear liquid to obtain the fuel.

[0071] The examples and comparative examples were made into fuels, and the sulfur content, acid value, kinematic viscosity, ash content, oxidation stability and low temperature performance of the fuels were measured. The data are shown in the following table:

[0072]

[0073]

[0074] Example 1 and Comparative Example 1

[0075] Diesel content: The diesel content of Comparative Example 1 is higher than that of Example 1 (38% vs 8%). Although the increase in diesel content will increase the energy density of the fuel, it will also lead to incomplete combustion and increase emission pollution;

[0076] Soybean oil content: soybean oil is added in Example 1, while this component is deleted in Comparative Example 1. Soybean oil is a renewable resource that can reduce the carbon emission of fuel, improve the renewability of fuel, and also help improve the lubricity of fuel;

[0077] in:

[0078] Sulfur content: The sulfur content of Example 1 is much lower than that of Comparative Example 1, indicating that the formula and preparation method of Example 1 are more conducive to reducing sulfur content and reducing environmental pollution;

[0079] Acid value: The acid value of Example 1 is extremely low, indicating that it contains very little acidic substances and is less corrosive to engine parts, while the acid value of Comparative Example 1 is relatively high;

[0080] Kinematic viscosity: The kinematic viscosity of Example 1 is moderate, which is conducive to the injection and combustion of the fuel, while the kinematic viscosity of Comparative Example 1 is high, which affects the injection performance of the fuel;

[0081] Ash content: Example 1 has a lower ash content, indicating that there are fewer impurities in the fuel and less ash is produced after combustion, while the ash content of Comparative Example 1 is relatively high;

[0082] Oxidation stability: The oxidation stability time of Example 1 is longer, indicating that the fuel has better anti-oxidation performance during storage and use, while the oxidation stability time of Comparative Example 1 is shorter;

[0083] Low temperature performance: The low temperature performance of Example 1 is better, indicating that the fuel has good fluidity and filterability under low temperature conditions, while the low temperature performance of Comparative Example 1 is poor.

[0084] Example 2 and Comparative Example 2

[0085] Alkaline zeolite catalyst: In Example 2, an alkaline zeolite catalyst was used, while in Comparative Example 2, this component was removed. The alkaline zeolite catalyst can promote the reaction between fuel components and improve the quality and performance of the fuel;

[0086] in:

[0087] Sulfur content: The sulfur content of Example 2 and Comparative Example 2 is low, but the sulfur content of Example 2 is slightly lower than that of Comparative Example 2, indicating that the use of the catalyst helps to further reduce the sulfur content;

[0088] Acid value: The acid value of Example 2 is lower than that of Comparative Example 2, indicating that the use of the catalyst can reduce the content of acidic substances in the fuel;

[0089] Kinematic viscosity: The kinematic viscosity of Example 2 is slightly higher than that of Comparative Example 2, but still within a reasonable range, indicating that the catalyst has little effect on the kinematic viscosity;

[0090] Ash content: The ash content of Example 2 is slightly lower than that of Comparative Example 2, indicating that the catalyst helps to reduce the impurity content in the fuel;

[0091] Oxidation stability: The oxidation stability time of Example 2 is longer than that of Comparative Example 2, indicating that the catalyst can improve the anti-oxidation performance of the fuel;

[0092] Low temperature performance: The low temperature performance of Example 2 is better than that of Comparative Example 2, indicating that the catalyst has a certain effect on improving the low temperature performance of the fuel.

[0093] Comparison of steps (Example 3 and Comparative Example 3)

[0094] Filtration and refining process

[0095] Comparison of supercritical fluid extraction with traditional filtration and precipitation:

[0096] The supercritical fluid extraction of Example 3 has high selectivity and high efficiency, can effectively separate different components in the fuel, and improve the purity and quality of the fuel. Its operating temperature is relatively low (35-40° C.), which is conducive to maintaining the stability of the fuel. At the same time, the pressure is relatively high (7.5-8 MPa), which can better dissolve and separate the components, and the residence time is relatively long (45-50 minutes), which can ensure sufficient contact and separation.

[0097] In comparative example 3, the traditional filtration and sedimentation have relatively low filtration accuracy and are difficult to completely remove tiny particles and impurities in the fuel. The ceramic membrane filtration pore size is large (greater than 50nm) and cannot effectively separate some tiny impurity particles. The static sedimentation time is long (1-2 hours), resulting in low efficiency. In addition, some impurities will be re-suspended in the liquid during the sedimentation process, affecting the purity of the fuel.

[0098] Refining treatment

[0099] Example 3: Hydrodesulfurization and sodium carbonate solution treatment can effectively reduce the sulfur content and acid value in the fuel, improve the environmental performance and corrosion resistance of the fuel, and vacuum drying and fine filtration can further ensure the dryness and cleanliness of the fuel;

[0100] The control of sulfur content, acid value and moisture content in Comparative Example 3 is not as accurate as that in Example 3, resulting in relatively poor environmental performance and stability of the fuel.

[0101] In summary, the formula and preparation method of Example 3 are superior to those of Comparative Example 3 in reducing sulfur content, acid value, ash content, and improving kinematic viscosity, oxidation stability and low-temperature performance, and the application of supercritical fluid extraction technology further improves the purity and quality of the fuel.

[0102] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a liquid wax alcohol ether composite diesel fuel, characterized in that: The following steps are involved: Step 1, prepare raw materials: prepare diesel, liquid wax, soybean oil, polyethylene glycol ether, aromatic alcohol polyoxyethylene ether, oxidant, metal passivator, low temperature fluidity improver, pour point depressant, composite emulsifier and alkaline zeolite catalyst with formula proportion; Step 2: Raw material pretreatment: Dehydrate and filter the diesel, and heat the liquid wax and soybean oil at 40-45°C respectively; Step 3, mixing: mix the pretreated soybean oil, diesel and polyethylene glycol ether, stir evenly in mixing tank A, the mixing time is 5-7 minutes, mix the pretreated liquid wax and aromatic alcohol polyoxyethylene ether in mixing tank B, stir evenly, the mixing time is 6-9 minutes; Step 4: Adding alkaline zeolite catalyst for reaction: connecting the mixtures in stirring tanks A and B to stirring tank C through pipes at both ends, stirring evenly in stirring tank C, and adding alkaline zeolite catalyst during the stirring process. The stirring time is 12-15 minutes, and nitrogen with a concentration of more than 99% is introduced during the reaction; Step 5, adding additives: maintaining the reaction temperature, sequentially adding a composite emulsifier, an oxidant, a metal passivator, a pour point depressant and a low-temperature fluidity improver to the C stirring tank and stirring for 8-12 minutes to obtain a mixture; Step 6: Filtration and purification: Use supercritical fluid technology to extract and separate the mixture, and finally obtain diesel fuel; Step 7. Waste treatment and recycling: A closed-loop production system is implemented throughout the entire process from step 1 to step 6 to recycle the waste generated during the production process.

2. The method for preparing a liquid wax alcohol ether composite diesel fuel according to claim 1, characterized in that: The raw materials and their weight ratio range are: diesel 8% to 13%; liquid wax 9% to 15%; soybean oil 17% to 23%; polyethylene glycol ether 20% to 27%; aromatic alcohol polyoxyethylene ether 14% to 18%; oxidant 1.2% to 1.9%; metal passivator 0.3% to 0.8%; low-temperature fluidity improver 1.1% to 1.3%; pour point depressant 0.08% to 0.15%; composite emulsifier 3.3% to 4.0%; and alkaline zeolite catalyst 2.5% to 3.0%.

3. The method for preparing a liquid wax alcohol ether composite diesel fuel according to claim 2, characterized in that: The raw materials and their weight ratio are: 8% diesel; 9% liquid wax; 23% soybean oil; 27% polyethylene glycol ether; 14% aromatic alcohol polyoxyethylene ether; 1.9% oxidant; 0.3% metal passivator; 1.5% low-temperature fluidity improver; 0.095% pour point depressant; 3.6% composite emulsifier; and 2.98% alkaline zeolite catalyst.

4. The method for preparing a liquid wax alcohol ether composite diesel fuel according to claim 2, characterized in that: The raw materials and their weight ratio are: diesel 12%, liquid wax 11%, soybean oil 19%, polyethylene glycol ether 21%, aromatic alcohol polyoxyethylene ether 15%, oxidant 1.6%, metal passivator 0.4%, low-temperature fluidity improver 1.23%, pour point depressant 0.085%, composite emulsifier 3.67% and alkaline zeolite catalyst 2.6%.

5. The method for preparing a liquid wax alcohol ether composite diesel fuel according to claim 1, characterized in that: The oxidant is composed of butylated hydroxyanisole and octaphenyl propoxy phosphine in a ratio of 1:

1.

6. The method for preparing a liquid wax alcohol ether composite diesel fuel according to claim 1, characterized in that: The metal passivator is phytic acid, and the low-temperature fluidity improver is selected from one of glycerol ether derivatives, amidate additives and ozonated vegetable oils.

7. The method for preparing a liquid wax alcohol ether composite diesel fuel according to claim 1, characterized in that: The pour point depressant consists of a 3:2:2 ethylene-vinyl acetate copolymer, petroleum sulfate and a benzene-containing terpolymer.

8. The method for preparing a liquid wax alcohol ether composite diesel fuel according to claim 1, characterized in that: The composite emulsifier consists of n-butanol, oleic acid and ferrocene in a ratio of 1:2:

1.

9. The method for preparing a liquid wax alcohol ether composite diesel fuel according to claim 1, characterized in that: The reaction conditions for adding the alkaline zeolite catalyst in step 4 are: the pressure is controlled between 1.5 and 2.0 times the standard atmospheric pressure, and the temperature is controlled between -5°C and 30°C.

10. The method for preparing a liquid wax alcohol ether composite diesel fuel according to claim 1, characterized in that: The filtering and refining process in step 6 is as follows: S6.

1. Coarse filtration: The mixture is filtered through a plate and frame filter with a pore size of 50 to 100 microns. The flow rate is controlled at 1.5 to 2.5 m / s. 3 / h; S6.2, supercritical fluid extraction: select carbon dioxide as the supercritical fluid, control the temperature at 35-40°C, control the pressure at 7.5-8MPa, put the coarsely filtered mixture into a supercritical fluid extractor, make the CO2 fluid fully contact with the mixture, control the residence time at 45-50 minutes, and then enter the separator; S6.3, Separation and collection: In the separator, the pressure is reduced to 3.5-4 MPa, and the temperature is increased to 50-55°C. The fuel is separated from the CO2 fluid and condensed at the bottom of the separator. The fuel is collected through a valve; S6.4, Refining treatment: Use hydrodesulfurization method to reduce the sulfide content in the fuel to below 0.05%, add 10ml of 5% sodium carbonate solution to reduce the acid value to below 0.01mgKOH / g, and reduce the water content of the fuel to below 0.05% by vacuum drying. Finally, use a fine filter with a filter element pore size of 2 to 3 microns to perform final filtration on the fuel to obtain high-purity diesel fuel.

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