A diesel blending component and preparation method thereof

Abstract

The present invention provides a diesel blending component and a preparation method thereof. The preparation method comprises the following steps: subjecting a hydrocarbon-containing raw material to a polymerization reaction under the catalytic action of a catalyst, washing and hydrogenating the reaction product to obtain the diesel blending component; the hydrocarbon-containing raw material comprises a first olefin raw material and a second olefin raw material, wherein the first olefin raw material is C4 to C 10 At least one of the normal olefins, the second olefin raw material is C4~C 10 At least one of the isoolefins; and the catalyst comprises a main catalyst and a phosphorus-containing compound. Also provided is a diesel blending component obtained using the above-mentioned preparation method. The preparation 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 petrochemical industry and relates to a method for producing diesel blending components. Background Art

[0002] The pour point is one of the main indicators of diesel and is directly related to its low-temperature performance.

[0003] There are many publicly reported studies on the production technology of low-freezing point diesel, and there are relatively mature industrial technologies. Among them, CN103224810A describes a method for producing low-freezing point diesel of No. -10 to No. -35 by a two-stage hydrogenation modification and degreasing process using crude oil fractions as raw materials. CN103805252A discloses a method for producing low-freezing point diesel of No. -35 by a high-efficiency and low-cost hydrogenation and degreasing process. CN1952042A describes a method for producing low-freezing point diesel of No. -30 by a combined hydrogenation modification and isomerization degreasing process using coal tar fractions as raw materials. CN109666510A discloses a method for producing ultra-low-freezing point diesel by a combined hydrocracking and hydromodification process using medium-temperature coal tar as raw material, and the freezing point of the ultra-low-freezing point diesel can reach -60°C.

[0004] After studying existing low-pour-point diesel production technologies in this field, it was found that existing research mainly has the following common characteristics: based on distillate oil feedstock, through processes such as hydrocracking, hydrorefining, hydrodegassing, and isodewaxing, chemical reactions such as normal paraffin isomerization, polycyclic aromatic hydrocarbon saturation, and heavy oil molecular cracking are achieved, thereby converting non-ideal components in the distillate oil into ideal components. The problem with existing research is that the distillates of crude oil, Fischer-Tropsch synergistic oil, or coal tar systems are complex hydrocarbon mixtures and contain a large number of high-pour-point non-ideal components. For example, crude oil and coal tar distillates both contain a large amount of polycyclic aromatic hydrocarbons, and the heavy fraction of Fischer-Tropsch synergistic oil is composed of more than 80% normal paraffins. Therefore, the upper limit of the process route for producing low-viscosity diesel based on distillate oil is limited; reflected in actual industrial production, the difficulty of producing -35 and -50 low-viscosity diesel is relatively high, and often requires specific crude oil raw materials for processing and production; alternatively, the production of low-grade low-viscosity diesel can be achieved through methods such as tail cutting and blending with jet fuel components, but such methods will reduce the combustion performance and stability of diesel products. Summary of the Invention

[0005] In response to the problems encountered in the existing low-freezing-point diesel production process, especially the difficulty that product quality is greatly limited by the influence of the properties of the processed raw materials, after detailed and in-depth research, a diesel blending component and its preparation method were proposed.

[0006] The technical solution provided by the present invention includes the following aspects:

[0007] 1. The present invention provides a method for preparing a diesel blending component, wherein the method comprises subjecting a hydrocarbon-containing raw material to a polymerization reaction under the catalytic action of a catalyst, and washing and hydrogenating the reaction product to obtain a diesel blending component;

[0008] The hydrocarbon-containing raw material includes a first olefin raw material and a second olefin raw material, wherein the first olefin raw material is C4-C 10 At least one of the normal olefins, the second olefin raw material is C4~C 10 At least one of the isomeric olefins; the catalyst comprises a main catalyst and a phosphorus-containing compound; the molar ratio of the main catalyst to the phosphorus-containing compound is 1:0.003-0.2, preferably 1:0.01-0.03.

[0009] Furthermore, in the above-mentioned method for preparing the diesel blending component, as a preferred embodiment, the phosphorus-containing compound is phosphotungstic acid and / or phosphomolybdotungstic acid, preferably phosphotungstic acid.

[0010] Furthermore, in the above-mentioned method for preparing diesel blending components, as a preferred embodiment, the main catalyst 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.

[0011] Furthermore, in the above-mentioned method for preparing the diesel blending component, as a preferred embodiment, the main catalyst can be one or a mixture of two or more selected from aluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, dimethylaluminum chloride, diethylaluminum chloride, n-butylaluminum dichloride, tert-butylaluminum dichloride, triethylaluminum, ferric chloride, and titanium tetrachloride; preferably, it is selected from one or a mixture of two or more selected from aluminum chloride, diethylaluminum chloride, and triethylaluminum.

[0012] Furthermore, in the above-mentioned method for preparing the diesel blending component, as a preferred embodiment, the first olefin raw material is at least one of C4 to C6 normal olefins.

[0013] Furthermore, in the above-mentioned method for preparing the diesel blending component, as a preferred embodiment, the second olefin feedstock is at least one of C4 to C6 isoolefins.

[0014] Furthermore, in the above-mentioned method for preparing the diesel blending component, as a preferred embodiment, the first olefin feedstock includes α-olefins (normal terminal olefins, normal olefins with olefin double bonds at the terminal positions) and normal internal olefins (normal olefins with olefin double bonds not at the terminal positions).

[0015] Furthermore, in the above-mentioned method for preparing the diesel blending component, as a preferred embodiment, in the hydrocarbon-containing raw material, based on the total weight of the hydrocarbon-containing raw material, the mass fraction of α-olefins in the first olefin raw material is 10% to 80%, preferably 25% to 75%; the mass fraction of normal internal olefins in the first olefin raw material is 2% to 50%, preferably 5% to 40%.

[0016] Furthermore, in the above-mentioned method for preparing the diesel blending component, as a preferred embodiment, the mass fraction of the second olefin feedstock is 2% to 50%, preferably 5% to 40%, based on the total weight of the hydrocarbon-containing feedstock.

[0017] Furthermore, in the above-mentioned method for preparing the diesel blending component, as a preferred embodiment, the hydrocarbon-containing raw material may optionally contain C4 to C 10 The total mass of the alkanes does not exceed 50% of the total mass of the hydrocarbon-containing feedstock, and preferably does not exceed 40% of the total mass of the hydrocarbon-containing feedstock.

[0018] Furthermore, in the above-mentioned method for preparing the diesel blending component, as a preferred embodiment, the molar ratio of the main catalyst in the catalyst to the olefins in the hydrocarbon-containing feedstock is 1:20-200, preferably 1:70-150.

[0019] Furthermore, in the above-mentioned method for preparing the diesel blending component, as a preferred embodiment, the polymerization reaction temperature is 20°C to 200°C, preferably 100°C to 150°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 0.5 to 8 h.

[0020] Furthermore, in the above-mentioned method for preparing the diesel blending component, as a preferred embodiment, washing is generally performed by water washing, and the water washing temperature is generally controlled at 20-80° C., and washing is performed until the hydrogenation feed index requirements are met.

[0021] Furthermore, in the above-mentioned preparation method of the diesel blending component, as a preferred embodiment, the hydrotreatment is to contact the reaction product with hydrogen in the presence of a hydrotreating catalyst to carry out a hydrotreating reaction, and 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 330-400°C are collected to obtain the diesel blending component.

[0022] Furthermore, in the above-mentioned preparation method of diesel blending component, as a preferred embodiment, the hydrofining reaction conditions are as follows: reaction temperature is 100°C to 350°C, preferably 150°C to 250°C; hydrogen partial pressure is 2.0 to 20.0 MPa, preferably 4.0 to 10.0 MPa; volume space velocity is 0.1 to 2.5 h -1 , preferably 0.5 to 2.0 hours -1; The volume ratio of hydrogen to oil is 200 to 2000, preferably 500 to 1000.

[0023] Furthermore, in the above-mentioned method for preparing the diesel blending component, as a preferred embodiment, the hydrotreating catalyst can be a commercially available product or prepared by 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.

[0024] The second aspect of the present invention provides a diesel blending component obtained by the above preparation method.

[0025] A third aspect of the present invention provides a low-freezing-point diesel, which comprises a diesel blending component obtained by the above-mentioned preparation method.

[0026] The present invention analyzes and summarizes existing problems in this field and concludes that in the field of low-freezing-point diesel, when the existing production process using distillate oil as raw material is adopted, the pour point of the diesel product is subject to the properties of the raw material and is extremely difficult to reach below -50°C. If a high-purity low-freezing-point isoparaffin component is obtained through directional synthesis of hydrocarbons, it can be used as a blending component for special ultra-low-freezing-point diesel. Its special properties have great application potential in high-altitude cold regions, polar scientific research, aerospace and other fields. In the field of synthetic isoparaffins, the technology of synthesizing isoparaffins from isobutylene is relatively mature, and a diesel distillate product can be obtained, but its cetane number is less than 20 and cannot be used as a diesel component.

[0027] Compared with the existing technology, the process route for preparing diesel blending components provided by the present invention has the following technical effects and advantages:

[0028] 1. During the research process, it was found that the pour point and cetane number of chain alkane molecules are positively correlated with the molecular weight, but negatively correlated with the number of branches; in order to obtain ideal ultra-low pour point diesel, the total number of branches needs to be moderate to reduce its 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 ultra-low pour point diesel blending component with a pour point below -70°C and a cetane number greater than 40. The product has a single hydrocarbon family composition (isomeric chain alkanes), and the product is highly pure, almost free of high pour point components such as aromatics and impurities such as sulfur and nitrogen. The ultra-low pour point diesel prepared with it as the core component far exceeds the products produced by existing distillate oil hydrogenation, isomerization degassing and other process routes in terms of low temperature performance indicators such as pour point and cloud point; the cetane number is high and the combustion performance is good; the harmful gases produced by combustion are less, it is safer and more environmentally friendly, and meets the requirements of the continuous upgrading of clean fuels.

[0029] 2. The present invention uses low-carbon mixed hydrocarbons containing olefins as raw materials, expanding the raw material source for low-viscosity diesel. With the continuous advancement of petrochemical industrial oil conversion, the low-carbon hydrocarbon byproducts produced by various related processes will increase significantly. The process route of the present invention has outstanding product performance, low raw material costs, simple reaction process, high yield, and good economic efficiency. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] In this article, all reagents or instruments used without indicating the manufacturer are conventional products that can be obtained through commercial channels.

[0033] 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%.

[0034] Example 1

[0035] A mixed C4-C5 hydrocarbon feedstock was used. The specific composition of the feedstock is shown in Table 1. An ultra-low pour point diesel blending component was synthesized in a batch reactor. The catalyst was 1 mol aluminum chloride and 0.01 mol phosphotungstic acid. 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 360°C was cut to obtain a diesel blending component. Its specifications are shown in Table 3.

[0036] Example 2

[0037] A mixed C4-C5 hydrocarbon feedstock was used. The specific composition of the feedstock is shown in Table 1. An ultra-low pour point diesel blending component was synthesized in a batch reactor. The catalyst was 0.5 mol aluminum chloride, 0.5 mol diethylaluminum chloride, and 0.03 mol phosphotungstic acid. 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 360°C was cut to obtain a diesel blending component. Its specifications are shown in Table 3.

[0038] Example 3

[0039] A mixed C4-C5 hydrocarbon feedstock was used. The specific composition of the feedstock is shown in Table 1. An ultra-low pour point diesel blending component was synthesized in a batch reactor. The catalyst consisted of 0.5 mol of diethylaluminum chloride, 0.5 mol of triethylaluminum, and 0.02 mol of phosphotungstic acid. 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 360°C was cut to obtain a diesel blending component. Its specifications are shown in Table 3.

[0040] Table 1 Composition of hydrocarbon-containing raw materials in Examples 1 to 3

[0041]

[0042]

[0043] Table 2 Reaction conditions of Examples 1-3

[0044]

[0045] Table 3 Product properties of Examples 1 to 3

[0046] Example 1 Example 2 Example 3 Cetane number 45 44 50 Freezing point, ℃ -80 -78 -75 Cloud point, ℃ -71 -67 -66 Yield, wt% 86.2 84.4 83.9

[0047] Example 4

[0048] The mixed hydrocarbons of C5-C6 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 100 mol. The ultra-low freezing point diesel blending component is synthesized by an intermittent tank reactor. The catalyst is 1.0 mol of aluminum chloride and 0.01 mol of phosphotungstic acid. The polymerization reaction conditions are as follows: temperature of 115°C, pressure of 5 MPa, reaction time of 3 h, and hydrofining reaction conditions: temperature of 150°C, hydrogen partial pressure of 6.0 MPa, hydrogen-to-oil volume ratio of 600, and space velocity of 2 h. -1 The hydrorefined product was subjected to vacuum distillation to cut the fraction with a boiling point between 180°C and 360°C to obtain a diesel blending component with a cetane number of 48, a freezing point of -76°C, a cloud point of -62°C, and a yield of 81.3wt%.

[0049] Table 4 Composition of hydrocarbon-containing raw materials in Example 4

[0050] 1-Pentene Isoamylene 2-Pentene n-pentane 1-Hexene n-hexane 30％ 20％ 10％ 20％ 10％ 10％

[0051] Example 5

[0052] C4~C 10 The mixed hydrocarbon is a hydrocarbon-containing raw material. The specific composition of the hydrocarbon-containing raw material is shown in Table 5. The total molar number of olefins is 100 mol. The ultra-low freezing point diesel blending component is synthesized by an intermittent tank reactor. The catalyst is 0.5 mol of diethylaluminum chloride, 0.5 mol of triethylaluminum and 0.01 mol of phosphotungstic acid. Among them, the polymerization reaction conditions are temperature of 120°C, pressure of 5 MPa, reaction time of 2.5 h, and hydrofining reaction conditions are: temperature of 200°C, hydrogen partial pressure of 5.0 MPa, hydrogen-to-oil volume ratio of 800, and space velocity of 2 h -1 The hydrorefined product was subjected to vacuum distillation to cut the fraction with a boiling point between 180°C and 360°C to obtain a diesel blending component with a cetane number of 52, a freezing point of -70°C, a cloud point of -57°C, and a yield of 79.6wt%.

[0053] Table 5 Composition of hydrocarbon-containing raw materials in Example 5

[0054] 1-Butene Isobutylene 2-Butene 1-Hexene 1-octene 1-Decene 20％ 30％ 20％ 10％ 10％ 10％

[0055] By analyzing the results of Examples 1 to 5, it can be seen that when the catalyst, raw materials and process of the present invention are used, the yield of the diesel blending component (calculated based on the mass of olefins) is high, the pour point of the diesel blending component can reach below -70°C, and the cloud point reaches below -60°C, indicating that the low-temperature performance of the blending component is extremely outstanding; at the same time, the cetane number of the diesel blending component reaches above 40, which can meet the requirements for use as a diesel component.

[0056] Comparative Example 1

[0057] The reaction was essentially the same as Example 1, except that the hydrocarbon feedstock had the following composition: 45 wt% 1-butene, 25 wt% 2-butene, 5 wt% 1-pentene, 5 wt% n-butane, 10 wt% isobutane, and 10 wt% n-pentane, with no isoolefins present. The reaction results are shown in Table 6.

[0058] Comparative Example 2

[0059] The reaction was essentially the same as Example 2, except that the hydrocarbon feedstock composition was as follows: 50 wt% 1-butene, 20 wt% isobutene, 5 wt% 1-pentene, 5 wt% n-butane, 10 wt% isobutane, and 10 wt% n-pentane, with no normal internal olefins present. The reaction results are shown in Table 6.

[0060] Comparative Example 3

[0061] The reaction was essentially the same as Example 3, except that the hydrocarbon feedstock had the following composition: 45 wt% 2-butene, 30 wt% isobutene, 5 wt% n-butane, 10 wt% isobutane, and 10 wt% n-pentane, with no normal terminal olefins present. The reaction results are shown in Table 6.

[0062] Comparative Example 4

[0063] 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.

[0064] Table 6 Comparative Example Product Properties

[0065] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Cetane number 56 48 25 28 Freezing point, ℃ -55 -66 -75 -63 Cloud point, ℃ -45 -51 -64 -50 Diesel fraction yield, wt% 61.0 68.2 80.5 23.1

[0066] Comparing the data in the table with the examples, it can be seen that the product of Comparative Example 1 has a higher pour point than that of the examples and a lower yield than that of the examples; the diesel fraction yields of Comparative Examples 2 and 4 are too low and the cetane numbers are also low; the product of Comparative Example 3 has an extremely low pour point, but a cetane number that is too low and cannot be used as a diesel blending component.

[0067] 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 preparing a diesel blending component, comprising subjecting a hydrocarbon-containing raw material to polymerization under the catalytic action of a catalyst, washing and hydrogenating the reaction product to obtain a diesel blending component; wherein: The hydrocarbon-containing feedstock includes a first olefin feedstock and a second olefin feedstock, wherein the first olefin feedstock has 4 to 10 carbon atoms and is composed of α-olefins and normal internal olefins. Based on the total weight of the hydrocarbon-containing feedstock, the mass fraction of α-olefins in the first olefin feedstock is 10% to 80%; the mass fraction of normal internal olefins in the first olefin feedstock is 2% to 50%; and the mass fraction of C4 to C 10 At least one of the isomerized olefins; the catalyst comprises a main catalyst and a phosphorus-containing compound; the main catalyst 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, the metal element is at least one of aluminum, iron, and titanium, and the phosphorus-containing compound is phosphotungstic acid and / or phosphomolybdotungstic acid; the molar ratio of the main catalyst to the phosphorus-containing compound is 1:0.003-0.2; the mass fraction of the second olefin feedstock is 2%-50% based on the total weight of the hydrocarbon-containing feedstock.

2. The method for preparing the diesel blending component according to claim 1, characterized in that: The main catalyst 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 preparing the diesel blending component according to claim 1, characterized in that: The main catalyst is one of aluminum chloride, diethylaluminum chloride and triethylaluminum or a mixture of two or more thereof.

4. The method for preparing the diesel blending component according to claim 1, characterized in that: The phosphorus-containing compound is phosphotungstic acid.

5. The method for preparing the diesel blending component according to claim 1, characterized in that: The molar ratio of the main catalyst to the phosphorus-containing compound is 1:0.01-0.

03.

6. The method for preparing the diesel blending component according to claim 1, characterized in that: The first olefin raw material has 4 to 6 carbon atoms.

7. The method for preparing the diesel blending component according to claim 1, characterized in that: The second olefin feedstock is at least one of C4 to C6 isomeric olefins.

8. The method for preparing the diesel blending component according to claim 1, characterized in that: Based on the total weight of the hydrocarbon-containing feedstock, the mass fraction of α-olefins in the first olefin feedstock is 25% to 75%; the mass fraction of normal internal olefins in the first olefin feedstock is 5% to 40%.

9. The method for preparing the diesel blending component according to claim 1, characterized in that: Based on the total weight of the hydrocarbon-containing feedstock, the mass fraction of the second olefin feedstock is 5% to 40%.

10. The method for preparing the diesel blending component according to claim 1, characterized in that: The hydrocarbon-containing raw materials contain C4~C 10 The total mass of saturated alkanes does not exceed 50wt% of the total mass of the hydrocarbon-containing raw material.

11. The method for preparing the diesel blending component according to claim 1, characterized in that: The hydrocarbon-containing raw materials contain C4~C 10 The total mass of saturated alkanes does not exceed 40wt% of the total mass of the hydrocarbon-containing raw material.

12. The method for preparing the diesel blending component according to claim 1, characterized in that: The molar ratio of the main catalyst in the catalyst to the olefins in the hydrocarbon-containing raw material is 1:20-200.

13. The method for preparing the diesel blending component according to claim 1, characterized in that: The molar ratio of the main catalyst in the catalyst to the olefins in the hydrocarbon-containing raw material is 1:70-150.

14. The method for preparing the diesel blending component according to claim 1, characterized in that: The polymerization reaction temperature is 20° C. to 200° C., and the reaction pressure is 1 to 30 MPa.

15. The method for preparing the diesel blending component according to claim 1, characterized in that: The polymerization reaction temperature is 100° C. to 150° C., and the reaction pressure is 2 to 10 MPa.

16. The method for preparing the diesel blending component according to claim 1, characterized in that: The hydrotreatment is to contact the washed reaction product with hydrogen in the presence of a hydrotreating catalyst to carry out a hydrotreating reaction, and 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 330-400°C are collected to obtain diesel blending components.

17. The method for preparing the diesel blending component according to claim 1, characterized in that: The hydrofining reaction 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 preparing the diesel blending component according to claim 1, characterized in that: The hydrofining reaction 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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