A high cetane number diesel blending component and its production method

Abstract

The present invention provides a high-cetane number diesel blending component and a production method thereof. A hydrocarbon-containing feedstock is contacted with a catalyst to undergo a polymerization reaction, and the reaction product is washed and hydrogenated to obtain the high-cetane number diesel blending component. The catalyst comprises component A, component B, and component C. Also provided is a high-cetane number diesel blending component obtained using the above production method. The production method of the present invention has a simple process, outstanding product performance, low raw material cost, high yield, and good economic efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of clean vehicle fuel, and in particular relates to a method for producing a high-cetane number diesel blending component. Background Art

[0002] The cetane number is one of the most important indicators of diesel fuel. It primarily reflects its compression ignition properties and is directly related to its performance, engine operation, and service life. Generally speaking, the cetane number of diesel fuel should not be too low. According to the national standard for automotive diesel fuel, GB 19147-2016, the cetane number of diesel fuel should generally be between 45 (for low-freezing point diesel) and 49 (for standard diesel fuels such as No. 0 and No. -10).

[0003] There are many publicly reported studies on the production technology of high cetane number diesel components, and the technical routes adopted are also different. For example, CN105524654A discloses a method for producing high cetane number low pour point diesel by a fixed bed two-stage hydrorefining-hydrogenation reforming process, and the cetane number of the diesel product reaches 45 to 55, and the pour point reaches about -40°C. CN106675040A describes a method for producing high cetane number low pour point diesel using inferior diesel as raw material through a fluidized bed hydroreforming and de-pour point process, and the cetane number of the diesel product is as high as 50 to 65, and the pour point can reach between -40°C and -50°C. CN101899320A describes a method for producing high cetane number diesel using a catalytic cracking process. CN103695033A discloses a method for producing high cetane number diesel using inferior diesel as raw material through a combined process of hydroreforming-solvent extraction, and the cetane number of the product reaches 50 to 65. CN104998668A describes a method for producing high-cetane biodiesel by hydrogenating biomass raw materials. The cetane number of the biodiesel can reach 60 to 65, and the pour point is around -10°C.

[0004] Existing high-cetane diesel production processes primarily involve hydrogenation, catalytic cracking, and solvent extraction to saturate or separate unsaturated components, particularly polycyclic aromatic hydrocarbons, from the feedstock, significantly improving the product's cetane number compared to the feedstock. However, existing production processes in this field struggle to produce diesel products / diesel components with a pour point below -50°C and a high cetane number. When a diesel product is fully hydrogenated and saturated, a high cetane number and a low pour point are two conflicting indicators: paraffins have a higher cetane number than cycloalkanes and aromatics and are the primary contributors to the diesel cetane number. Hydrodegradation / isomerization processes reduce the product's pour point by shortening the main carbon chain and increasing the number of branches, but this also reduces the product's cetane number. Therefore, the cetane number of low-cetane diesel is generally low, requiring the addition of additives or high-cetane components, or the complete separation of aromatic and cycloalkanes. Summary of the Invention

[0005] The main purpose of the present invention is to provide a high-cetane number diesel blending component and a production method thereof, which can effectively solve the problems encountered in the existing high-cetane number low-freezing point diesel production process, especially the problem that the product freezing point is greatly limited by the existing processing technology.

[0006] The first aspect of the present invention provides a method for producing a high cetane number diesel blending component. A hydrocarbon-containing raw material is contacted with a catalyst to cause a polymerization reaction, and the reaction product is washed and hydrogenated to obtain a high cetane number diesel blending component.

[0007] As a specific embodiment, the hydrocarbon-containing raw material includes raw material A and raw material B, wherein raw material A is at least one of α-olefins (straight-chain terminal olefins, straight-chain olefins with olefin double bonds at the terminal position) with a carbon number of 4-9, and raw material B is at least one of straight-chain internal olefins (straight-chain olefins with olefin double bonds not at the terminal position) with a carbon number of 4-9.

[0008] As a specific embodiment, the catalyst includes component A, component B and component C, wherein the molar ratio of component A, component B and component C is 1:0.003-0.2:0.01-1.0, preferably 1:0.01-0.03:0.1-0.4. Component A and component C are ether compounds;

[0009] As a specific embodiment, component A is one or a mixture of two or more of a halide containing a metal element, an alkyl halide containing a metal element, and an alkylate containing a metal element, wherein the metal element is at least one of aluminum, iron, and titanium.

[0010] As a specific embodiment, component A can be one or a mixture of two or more of aluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, dimethylaluminum chloride, diethylaluminum chloride, n-butylaluminum dichloride, tert-butylaluminum dichloride, triethylaluminum, ferric chloride, and titanium tetrachloride; preferably, it can be one or a mixture of two or more of aluminum chloride, diethylaluminum chloride, and triethylaluminum.

[0011] As a specific embodiment, component B is a phosphorus-containing compound, and the phosphorus-containing compound is phosphotungstic acid and / or phosphomolybdotungstic acid, preferably phosphotungstic acid.

[0012] As a specific embodiment, component C is an ether compound, and the ether compound is one or a mixture of two or more of dimethyl ether, diethyl ether, ethyl propyl ether, and dipropyl ether; preferably diethyl ether.

[0013] As a specific embodiment, the raw material A is at least one of α-olefins having 4 to 6 carbon atoms.

[0014] As a specific embodiment, the raw material B is at least one linear internal olefin having 4 to 6 carbon atoms.

[0015] As a specific embodiment, in the hydrocarbon-containing raw material, based on the total mass of the hydrocarbon-containing raw material, the mass fraction of raw material A is 30% to 95%, preferably 40% to 80%; the mass fraction of raw material B is 2% to 50%, preferably 5% to 30%.

[0016] As a specific embodiment, the hydrocarbon-containing raw material may optionally contain non-essential C4 to C 10 The total mass of the alkanes does not exceed 40 wt% of the total mass of the hydrocarbon-containing feedstock, and preferably does not exceed 30 wt% of the total mass of the hydrocarbon-containing feedstock.

[0017] As a specific embodiment, the molar ratio of component A in the catalyst to olefins in the hydrocarbon-containing feedstock is 1:20-200, preferably 1:80-150.

[0018] As a specific embodiment, the polymerization reaction temperature is 20°C to 200°C, preferably 80°C to 160°C; the reaction pressure is 1 to 30 MPa, preferably 2 to 10 MPa; and the reaction time is 0.1 to 24 h, preferably 1 to 10 h.

[0019] As a specific implementation method, the washing is generally water washing, and the water washing temperature is generally controlled at 20-80° C., and the washing is performed until the hydrogenation feed index requirements are met.

[0020] As a specific embodiment, the hydrotreatment process is to mix the obtained reaction product with hydrogen and then contact it with a hydrorefining catalyst for reaction, the reaction effluent is separated by vacuum distillation, and the fractions with an initial distillation point of 150-200°C and a final distillation point of 350-400°C are collected to obtain a high cetane number diesel blending component.

[0021] As a specific embodiment, the hydrogenation treatment conditions are as follows: reaction temperature is 100℃~350℃, hydrogen partial pressure is 2.0~20.0MPa, volume space velocity is 0.1~2.5h -1 , hydrogen to oil volume ratio is 200~2000; preferred hydrogenation treatment conditions are as follows: reaction temperature is 150℃~250℃; hydrogen partial pressure is 4.0~10.0Mpa; volume space velocity is 0.5~2.0h -1 ; The volume ratio of hydrogen to oil is 500~1000.

[0022] As a specific embodiment, the hydrotreating catalyst can be a commercially available product or prepared using existing methods in the art. Generally, the hydrotreating catalyst includes a carrier and an active metal component supported on the carrier. The active metal component can be at least one of Group VIB metals and / or Group VIII metals, for example, one or more of molybdenum, nickel, cobalt, platinum, ruthenium, rhodium and palladium can be selected; the carrier is an inorganic refractory metal oxide, specifically at least one of aluminum oxide, silicon oxide, magnesium oxide, titanium oxide and zirconium oxide can be selected.

[0023] The second aspect of the present invention provides a high cetane number diesel blending component obtained by the above production method.

[0024] Compared with the prior art, the method for producing high cetane number diesel blending components provided by the present invention has the following advantages:

[0025] 1. During the research process, it was found that the pour point and cetane number of paraffin molecules are positively correlated with the carbon chain length, and negatively correlated with the number of branches. In order to obtain a low pour point, high cetane number diesel blending component, the total number of branches needs to be moderate to reduce their negative impact on the cetane number. The core of the present invention is to control the carbon number distribution and branch length of the product, especially the number of branches, within a reasonable range through an innovative catalyst system and raw material system, to obtain a high-quality high cetane number, low pour point diesel blending component with a pour point below -50°C and a cetane number greater than 60. The product of the present invention has a single hydrocarbon family composition (isomeric paraffins) and is highly pure, containing almost no high pour point components such as aromatics and impurities such as sulfur and nitrogen. The high cetane number diesel prepared with this as the core component far exceeds the products produced by existing hydrogenation, catalytic cracking and other process routes in low temperature performance indicators such as pour point and cold filter plugging point; the cetane number is extremely high and the combustion performance is good; the combustion produces less harmful gases, is safer and more environmentally friendly, and meets the ever-increasing demand for clean fuels.

[0026] 2. The present invention uses low-carbon mixed hydrocarbons containing olefins as raw materials, expanding the raw material source for diesel blending components. With the continuous advancement of oil conversion in the petrochemical industry, the generation of low-carbon hydrocarbon byproducts from various related processes is expected to increase significantly. The process route of the present invention offers outstanding product performance, low raw material costs, a simple reaction process, high yield, and good economic efficiency. DETAILED DESCRIPTION

[0027] In order to better illustrate the present invention, the effects and effects of the method of the present invention are specifically described below in conjunction with embodiments, but the following embodiments do not constitute a limitation of the present invention.

[0028] If no specific conditions are specified in the following examples and comparative examples, the reactions were carried out according to conventional conditions or those recommended by the manufacturer.

[0029] In this article, all reagents or instruments used without indicating the manufacturer are conventional products that can be obtained through commercial channels.

[0030] In this paper, the hydrorefining catalyst used is Pt / Pd-Al2O3 catalyst, with a Pt content of 0.35wt% and a Pd content of 0.15wt%.

[0031] Example 1

[0032] A mixed C4-C5 hydrocarbon feedstock was used. The specific composition of the feedstock is shown in Table 1. A diesel blending component was synthesized in a batch reactor. The catalyst consisted of 1 mol triethylaluminum, 0.01 mol phosphotungstic acid, and 0.1 mol diethyl ether. Specific reaction conditions are shown in Table 2. The hydrorefined product was subjected to vacuum distillation, and the fraction with a boiling point between 180°C and 390°C was cut to obtain a diesel blending component. Its specifications are shown in Table 3.

[0033] Example 2

[0034] A mixed C4-C5 hydrocarbon feedstock was used. The specific composition of the feedstock is shown in Table 1. A diesel blending component was synthesized in a batch reactor. The catalyst consisted of 0.7 mol aluminum chloride, 0.3 mol diethylaluminum chloride, 0.03 mol phosphotungstic acid, and 0.4 mol diethyl ether. Specific reaction conditions are shown in Table 2. The hydrorefined product was subjected to vacuum distillation, and the fraction with a boiling point between 180°C and 390°C was cut to obtain a diesel blending component. Its specifications are shown in Table 3.

[0035] Example 3

[0036] A mixed C4-C6 hydrocarbon feedstock was used. The specific composition of the feedstock is shown in Table 1. A diesel blending component was synthesized in a batch reactor. The catalyst consisted of 0.5 mol diethylaluminum chloride, 0.5 mol triethylaluminum, 0.02 mol phosphotungstic acid, and 0.25 mol diethyl ether. Specific reaction conditions are shown in Table 2. The hydrorefined product was subjected to vacuum distillation, and the fraction with a boiling point between 180°C and 390°C was cut to obtain a diesel blending component. Its specifications are shown in Table 3.

[0037] Table 1 Composition of hydrocarbon-containing raw materials in Examples 1 to 3

[0038] composition Ratio, wt% 1-Butene 50 1-Pentene 20 1-Hexene 10 2-Butene 20

[0039] Table 2 Reaction conditions of Examples 1-3

[0040]

[0041]

[0042] Table 3 Product properties of Examples 1 to 3

[0043] Example 1 Example 2 Example 3 Cetane number 61 60 63 Freezing point, ℃ -66 -68 -72 Cold filter point, ℃ -53 -56 -62 Yield, wt% 87.7 90.4 89.6

[0044] Example 4

[0045] The mixed hydrocarbons of C4 to C9 are used as hydrocarbon raw materials. The specific composition of the hydrocarbon raw materials is shown in Table 4. The total molar number of olefins is 80 mol. The ultra-low freezing point diesel blending component is synthesized by an intermittent tank reactor. The catalyst is 1.0 mol triethylaluminum, 0.02 mol phosphotungstic acid and 0.3 mol diethyl ether. The polymerization reaction conditions are temperature of 140 ° C, pressure of 8 MPa, reaction time of 2 h, and hydrofining reaction conditions are: temperature of 150 ° C, hydrogen partial pressure of 6.0 MPa, hydrogen-to-oil volume ratio of 1000, and space velocity of 1.5 h -1 The hydrorefined product was subjected to vacuum distillation to cut the fraction with a boiling point between 180°C and 390°C to obtain a diesel blending component with a cetane number of 75, a pour point of -60°C, a cold filter point of -48°C, and a yield of 85.3wt%.

[0046] Table 4 Composition of hydrocarbon-containing raw materials in Example 4

[0047] composition Ratio, wt% 1-Butene 30 1-Hexene 30 1-octene 10 1-Nonene 10 n-hexane 20

[0048] Example 5

[0049] A mixed hydrocarbon of C4 to C8 is used as the hydrocarbon-containing raw material. The specific composition of the hydrocarbon-containing raw material is shown in Table 5, and the total molar number of olefins is 100 mol. The diesel blending component is synthesized by an intermittent tank reactor. The catalyst is 0.5 mol of diethylaluminum chloride, 0.5 mol of triethylaluminum, 0.01 mol of phosphotungstic acid and 0.15 mol of diethyl ether. The polymerization reaction conditions are as follows: temperature of 100°C, pressure of 5 MPa, reaction time of 3 h, and hydrorefining reaction conditions: temperature of 200°C, hydrogen partial pressure of 5.0 MPa, hydrogen-to-oil volume ratio of 800, and space velocity of 1.5 h -1 The hydrorefined product was subjected to vacuum distillation to cut the fraction with a boiling point between 180°C and 390°C to obtain a diesel blending component with a cetane number of 71, a pour point of -63°C, a cold filter point of -50°C, and a yield of 83.5wt%.

[0050] Table 5 Composition of hydrocarbon-containing raw materials in Example 5

[0051] 1-Butene 2-Butene 1-Hexene 1-octene n-hexane 40％ 30％ 10％ 10％ 10％

[0052] By analyzing the results of Examples 1 to 5, it can be seen that when the catalyst, raw materials and process methods of the present invention are used, the yield of the diesel blending component (calculated based on the mass of olefins) is high, the cetane number of the diesel blending component reaches 60 to 75, the pour point can reach below -60°C, and the cold filter plugging point reaches below -45°C, indicating that the low-temperature performance of the blending component is extremely outstanding and can be used as a cetane number improvement component for ultra-low pour point diesel.

[0053] Comparative Example 1

[0054] The reaction was basically the same as Example 1, except that the composition of the hydrocarbon feedstock was as follows: 62.5 wt% of 1-butene, 25 wt% of 1-pentene, 12.5 wt% of 1-hexene, and no normal internal olefins. The reaction results are shown in Table 6.

[0055] Comparative Example 2

[0056] The reaction was basically the same as Example 2, except that the composition of the hydrocarbon-containing feedstock was as follows: 50 wt% 1-butene, 20 wt% 1-pentene, 10 wt% 1-hexene, and 20 wt% isobutylene, i.e., isoolefins were used instead of normal internal olefins. The reaction results are shown in Table 6.

[0057] Comparative Example 3

[0058] The reaction was basically the same as in Example 1, except that the catalyst was aluminum chloride only. The reaction results are shown in Table 6.

[0059] Table 6 Comparative Example Product Properties

[0060] Comparative Example 1 Comparative Example 2 Comparative Example 3 Cetane number 65 46 58 Freezing point, ℃ -50 -65 -65 Cold filter point, ℃ -39 -53 -51 Diesel fraction yield, wt% 80.5 86.6 70.3

[0061] Comparing the data in the table with the examples, it can be seen that the product yield of Comparative Example 1 is lower than that of the examples, and the product freezing point is higher than that of the examples; the cetane number of the product of Comparative Example 2 is significantly lower than that of the examples; and the product yield of Comparative Example 3 is significantly lower than that of the examples.

[0062] The above descriptions are only some typical embodiments of the present invention and are not intended to limit the technical scope of the present invention. The content of the present invention is not limited to the above embodiments. Without departing from the purpose of the present invention, some non-essential improvements and adjustments still fall within the scope of protection of the present invention.

Claims

1. A method for producing a high-cetane diesel blending component, comprising contacting a hydrocarbon-containing feedstock with a catalyst to cause a polymerization reaction, and washing and hydrogenating the reaction product to obtain a high-cetane diesel blending component; The hydrocarbon-containing feedstock comprises feedstock A and feedstock B, wherein feedstock A is at least one of α-olefins having 4 to 9 carbon atoms, and feedstock B is at least one of linear internal olefins having 4 to 9 carbon atoms; based on the total mass of the hydrocarbon-containing feedstock, the mass fraction of feedstock A is 30% to 95%, and the mass fraction of feedstock B is 2% to 50%; The catalyst comprises component A, component B and component C, wherein component A is one or a mixture of two or more of a metal element halide, a metal element alkyl halide and a metal element alkylate, wherein: The metal element is at least one of aluminum, iron, and titanium; component B is a phosphorus-containing compound, and the phosphorus-containing compound is phosphotungstic acid and / or phosphomolybdotungstic acid; Component C is an ether compound; the molar ratio of component A, component B and component C is 1:0.003-0.2:0.01-1.

0.

2. The method for producing a high cetane number diesel blending component according to claim 1, wherein: Component A is one or a mixture of two or more of aluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, dimethylaluminum chloride, diethylaluminum chloride, n-butylaluminum dichloride, tert-butylaluminum dichloride, triethylaluminum, ferric chloride, and titanium tetrachloride.

3. The method for producing a high cetane number diesel blending component according to claim 1, wherein: Component A is one or a mixture of two or more of aluminum chloride, diethylaluminum chloride and triethylaluminum.

4. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The ether compound is one or a mixture of two or more of dimethyl ether, diethyl ether, ethyl propyl ether and dipropyl ether.

5. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The ether compound is diethyl ether.

6. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The phosphorus-containing compound is phosphotungstic acid.

7. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The molar ratio of component A, component B and component C is 1:0.01-0.03:0.1-0.

4.

8. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The raw material A is at least one of α-olefins having 4 to 6 carbon atoms.

9. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The raw material B is at least one linear internal olefin having 4 to 6 carbon atoms.

10. The method for producing a high cetane number diesel blending component according to claim 1, wherein: Based on the total mass of the hydrocarbon-containing raw materials, the mass fraction of raw material A is 40% to 80%; the mass fraction of raw material B is 5% to 30%.

11. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The hydrocarbon-containing raw material optionally contains C4 to C 10 The total mass of alkanes does not exceed 40wt% of the total mass of the hydrocarbon-containing raw material.

12. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The hydrocarbon-containing raw material optionally contains C4 to C 10 The total mass of alkanes does not exceed 30wt% of the total mass of the hydrocarbon-containing raw material.

13. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The molar ratio of component A in the catalyst to olefins in the hydrocarbon-containing raw material is 1:20-200.

14. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The molar ratio of component A in the catalyst to olefins in the hydrocarbon-containing raw material is 1:80-150.

15. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The polymerization reaction temperature is 20° C. to 200° C., and the reaction pressure is 1 to 30 MPa.

16. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The polymerization reaction temperature is 80° C. to 160° C., and the reaction pressure is 2 to 10 MPa.

17. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The hydrogenation treatment conditions are as follows: reaction temperature is 100℃~350℃, hydrogen partial pressure is 2.0~20.0MPa, volume space velocity is 0.1~2.5h -1 , the hydrogen-to-oil volume ratio is 200-2000.

18. The method for producing a high cetane number diesel blending component according to claim 1, wherein: The hydrogenation treatment conditions are as follows: reaction temperature is 150℃~250℃, hydrogen partial pressure is 4.0~10.0MPa, volume space velocity is 0.5~2.0h -1 , the hydrogen-to-oil volume ratio is 500-1000.

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