A method for producing a motor gasoline

Abstract

The application discloses a production method of vehicle gasoline. The method comprises the following steps: firstly, raw oil and hydrogen enter a reactor I to carry out gas phase reaction; the effluent of the reactor I is partially or totally changed into liquid phase state by pressurization, and then is subjected to liquid phase reaction in a reaction container II, so as to obtain vehicle gasoline. The application adopts a hydrogen desulfurization route, combines the vaporization process and liquefaction process of the raw oil and hydrogen, strengthens the uniform mixing and dissolution of hydrogen and raw oil by using phase change process, realizes the partition reaction of sulfides, olefins and aromatic hydrocarbons in the raw oil, strengthens the reaction efficiency and improves the product quality.

Description

Technical Field

[0001] This invention belongs to the field of oil refining and chemical industry, and specifically relates to a method for producing automotive gasoline. Background Technology

[0002] With increasingly stringent environmental regulations, the quality standards for gasoline and diesel fuel for vehicles are constantly being raised. In the gasoline sector, the latest standard is the China VI standard, which stipulates that the olefin content in gasoline is ≤15% vol%, the aromatic content is ≤35% vol%, and the sulfur content is ≤10 μg·g. -1 This presents new challenges to gasoline production technology. While deeply desulfurizing gasoline, it's crucial to control the content of olefins and aromatics, and simultaneously ensure that the octane number of gasoline products meets standards. Traditional gasoline production technology primarily relies on S-Zorb, a non-hydrogenation route that removes sulfides from gasoline using adsorbents, while unsaturating olefins and aromatics, achieving the production of low-sulfur, high-octane gasoline. However, facing increasingly stringent restrictions on olefin and aromatic content in the future, S-Zorb technology is ill-suited to future technological developments because it cannot perform hydrogenation reactions on olefins and aromatics. Traditional hydrogenation-based gasoline production, on the other hand, involves segmenting the feedstock based on the different boiling points of sulfides and olefins. The light components rich in olefins are treated with alkali-free deodorization, while the heavy components rich in large-molecule sulfides are treated with selective hydrogenation desulfurization catalysts, aiming to desulfurize while minimizing olefin saturation. Early on, due to less stringent restrictions on olefin and aromatic content in gasoline standards, this technology was replaced by S-Zorb. However, facing future gasoline quality regulations, hydrogenation-based gasoline production needs further upgrading and development.

[0003] Currently, the main problems with the hydrotreating process for producing high-octane gasoline are as follows: the process is relatively complex because the raw materials need to be fractionated and processed separately; in addition, the hydrogen consumption is slightly higher due to the fixed-bed hydrotreating reaction; and hydrogen sulfide is generated during the hydrodesulfurization reaction, which is relatively easy to be converted into mercaptans, affecting product quality.

[0004] CN106554813A discloses a process for producing low-sulfur, low-olefin, high-octane gasoline. This process involves oxidizing the fractionated light components to generate high-octane components via olefin oxidation, while the heavy components undergo hydrodesulfurization followed by fractionation. The separated heavy components are then subjected to solvent extraction to remove sulfur-containing substances. The processed components are then mixed to obtain low-sulfur, low-olefin, high-octane gasoline. However, this process is complex, involves multiple fractionation steps, and consumes a large amount of energy.

[0005] CN104611062A discloses a method for producing high-octane gasoline. This method uses catalytic diesel as feedstock, loading a hydrocracking catalyst into the stripping section and an isomerization catalyst into the rectifying section of a reactive distillation tower. By subjecting the diesel components to hydrocracking, the lighter components are re-isomerized, thus producing high-octane gasoline. However, during the hydrocracking process, this method essentially saturates all the olefins in the catalytic diesel, resulting in high hydrogen consumption and hindering the preservation of the gasoline's octane number. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a method for producing automotive gasoline. This invention employs a hydrodesulfurization route and combines the vaporization and liquefaction processes of the feedstock oil with hydrogen. It utilizes a phase change process to enhance the uniform mixing and dissolution of hydrogen with the feedstock, and achieves zoned reactions of sulfides, olefins, and aromatics in the feedstock, thereby improving reaction efficiency and product quality. The resulting automotive gasoline meets the China VI emission standard.

[0007] A method for producing automotive gasoline according to the present invention includes:

[0008] The feedstock oil and hydrogen first enter reactor I and undergo a gas phase reaction; the effluent from reactor I is pressurized and partially or completely converted into a liquid phase state, and then undergoes a liquid phase reaction in reaction vessel II to finally obtain automotive gasoline.

[0009] Furthermore, the feedstock oil can be one or more of catalytic gasoline, straight-run naphtha, coking naphtha, etc.

[0010] Furthermore, the feedstock oil generally has a distillation range of 40–200°C, S ≯ 2000 μg / g, preferably 100–1000 μg / g, olefins ≯ 40 wt%, preferably 10 wt%–25 wt%, aromatics ≯ 50 wt%, preferably 15 wt%–45 wt%, and an octane number (RON) of not less than 70, preferably 75–90.

[0011] Furthermore, reactor I is preferably a conventional fixed-bed reactor. Reactor I is packed with a catalyst possessing selective hydrodesulfurization and isomerization functions, comprising a support and a hydrogenation-active metal component. The support is an inorganic refractory oxide, generally selected from one or more of alumina, amorphous aluminum silicate, silica, or titanium dioxide; the hydrogenation-active metal includes Group VIB and / or Group VIII metal components, where Group VIB is selected from tungsten and / or molybdenum, at 1%–15% (preferably 2%–10%) based on oxides, and Group VIII is selected from nickel and / or cobalt, at 1%–15% (preferably 3%–9%) based on oxides. Examples include the FGH series catalysts or ME series catalysts developed by the Dalian Petrochemical Research Institute.

[0012] Furthermore, the operating conditions of the reactor I include: a reaction pressure of 0.1–3.0 MPa, preferably 0.5–2.0 MPa; a hydrogen-to-oil volume ratio of 10–1000, preferably 80–300; and a reaction temperature of 50–300°C, preferably 100–230°C.

[0013] Furthermore, the pressurization can be achieved using any commercially available compressor, such as a reciprocating or centrifugal compressor, with no special requirements on specific specifications or models.

[0014] Furthermore, reactor II is filled with a hydrorefining catalyst, which includes a support and a hydrorefining active metal; wherein the support is an inorganic refractory oxide, generally selected from one or more of alumina, amorphous aluminum silicate, silica or titanium dioxide; the hydrorefining active metal includes group VIB and / or group VIII metal components, wherein the group VIB metal is selected from tungsten and / or molybdenum, and is 5% to 25% by oxide, preferably 10% to 20%, and the group VIII metal is selected from nickel and / or cobalt, and is 1% to 7% by oxide, preferably 1.5% to 5%, such as the FH-40 series catalyst developed by Dalian Petrochemical Research Institute.

[0015] Furthermore, the operating conditions of reactor II include: a reaction pressure of 0.1–6.0 MPa, preferably 2.5–4.0 MPa; a reaction temperature of 100–300 °C, preferably 140–220 °C; and a volume hourly space velocity of 1.5–3.5 h⁻¹. -1 The reaction pressure in reactor II is 0.5–3.5 MPa higher than that in reactor I.

[0016] Furthermore, the liquefaction rate of hydrogen and feedstock oil in reactor II is generally controlled to be no less than 30%, preferably 40% to 80%.

[0017] Furthermore, the top effluent from reactor II is a gaseous component, which passes through a heat exchanger and / or condenser, and then enters a high-pressure separator to obtain a liquid light component.

[0018] Furthermore, the heavy liquid components obtained from the liquid phase reaction in reactor II are discharged from the bottom of reactor II, and the heavy liquid components are mixed with the light liquid components to obtain automotive gasoline products.

[0019] Furthermore, the properties of the gasoline include: octane number ≥ 95, sulfur content ≤ 10 μg·g. -1 Olefin content ≤ 15% v, aromatic content ≤ 35% v.

[0020] Compared with the prior art, the method of the present invention has the following advantages:

[0021] (1) Compared with the conventional hydrotreating process for gasoline production, this invention allows for separate desulfurization and dearomatization reactions, while simultaneously controlling the olefin saturation rate. Desulfurization and shallow olefin saturation occur in reactor I. Due to the high linear velocity of the reactant stream along the reactor axis and the low-pressure environment during the gas-phase reaction, the aromatic hydrocarbon hydrogenation reaction will not occur in reactor I. By controlling the liquefaction rate of the effluent from reactor I, while achieving uniform dissolution of hydrogen in the oil, it is also possible to separate small-molecule olefins from large-molecule sulfides and aromatics, allowing the large-molecule components to undergo further hydrogenation and desulfurization isomerization reactions, thus reducing octane number loss.

[0022] (2) Compared with liquid phase hydrogenation technology, this invention uses a phase change process of vaporization and reliquefaction of hydrogen and feedstock oil to enhance hydrogen dissolution, which makes up for the defects of conventional liquid phase technology, such as poor hydrogen dissolution effect of forced back-mixing of gaseous hydrogen and liquid feedstock and high cost of membrane hydrogen mixing equipment, thus achieving low-cost hydrogen dissolution and enhanced hydrogen mixing effect.

[0023] (3) In this invention, after vaporizing the feedstock oil and hydrogen, the effluent from reactor I is liquefied using a pressurized method. Taking advantage of the higher solubility of hydrogen at high temperatures, the solubility of hydrogen in reactor II is increased, which is beneficial for the hydrogenation reaction. Simultaneously, since a desulfurization reaction is involved in reactor I, generating hydrogen sulfide, which has low solubility at high temperatures, the concentration of hydrogen sulfide in the large molecular components entering reactor II is kept low, optimizing the reaction environment. No stripping device is needed between the two reactors. For the unliquefied small molecular components, liquefaction is achieved by cooling, which reduces the concentration of impurities such as hydrogen sulfide and ammonia in the liquefied components, reducing subsequent stripping pressure and further saving energy and reducing consumption. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the high-octane gasoline production process in Examples 1-3 of the present invention;

[0025] Wherein: 1-Federal feedstock and hydrogen, 2-Reactor I, 3-Effluent from Reactor I, 4-Compressor, 5-Reactor II, 6-Liquid phase heavy components, 7-Gas phase components, 8-Heat exchanger, 9-Condenser, 10-High pressure separator, 11-Liquid phase light components, 12-Automotive gasoline. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments, but this does not limit the scope of the invention.

[0027] by Figure 1To illustrate a process flow for producing automotive gasoline according to the present invention: Raw material oil and hydrogen 1 enter reactor 2. Under suitable pressure, hydrogen / raw material volume ratio, and temperature, all or part of the raw material and hydrogen are vaporized, and a shallow hydrogenation reaction occurs. The effluent 3 from reactor 1 enters compressor 4. After being pressurized by compressor 4, it enters reactor 5 as a liquid phase or a two-phase gas-liquid mixture. In reactor 5, the hydrogen-dissolved liquid phase component undergoes a hydrogenation / isomerization reaction to obtain a liquid phase heavy component 6. The unliquefied gas phase light component 7 then sequentially enters heat exchanger 8 and condenser 9, and subsequently enters high-pressure separator 10 to obtain a liquid phase light component 11. The liquid phase light component 11 and the liquid phase heavy component 6 are mixed to obtain automotive gasoline 12.

[0028] Examples 1-3

[0029] This embodiment employs two 100mL fixed-bed hydrogenation reactors connected in series, with a reciprocating compressor between the reactors. Reactor I is a gas-phase hydrogenation reactor, loaded with 50mL of catalyst A, which has selective hydrodesulfurization and isomerization functions. Reactor II is a liquid-phase hydrogenation reactor, loaded with 50mL of hydrorefining catalyst B. A gas phase outlet is located at the top of reactor II, connected to a heat exchanger, condenser, and high-pressure separator. The liquid phase outlet pipeline at the bottom of reactor II is connected to the bottom liquid phase outlet pipeline of the high-pressure separator, both entering the subsequent stripping and fractionation equipment. Catalytic gasoline is used as feedstock. Catalyst properties are shown in Table 1, feedstock properties in Table 2, and reaction process conditions and results in Table 3.

[0030] Comparative Example 1

[0031] The conventional gasoline production process involves first fractionating the catalytic gasoline feedstock at 80°C. After fractionation, the olefin-rich light components, below 80°C, undergo alkali-free deodorization to convert small-molecule sulfides (thiols) into large-molecule sulfides (sulfides, disulfides), which are then absorbed by catalytic diesel fuel. The sulfur- and aromatic-containing heavy components above 80°C enter the hydrogenation unit, which is equipped with a hydrogenation reactor, designated Reactor 1. It is loaded with 50 mL of selective hydrogenation refining catalyst A and 50 mL of hydrogenation refining catalyst B. The effluent from Reactor 1 is further refined and stripped before being mixed with the light components to produce the gasoline product. The feedstock properties are the same as in Examples 1-3, and the reaction process conditions and results are shown in Table 3.

[0032] Comparative Example 2

[0033] Two hydrogenation reactors were connected in series. Reactor 1 was loaded with 50 mL of Mo-Co type selective hydrogenation refining catalyst A, and reactor 2 was loaded with 50 mL of hydrogenation refining catalyst B. Both reactors used conventional gasoline hydrogenation reaction conditions. The properties of the feedstock were the same as in Examples 1-3. The reaction process conditions and results are shown in Table 3.

[0034] Table 1. Physicochemical properties of catalysts

[0035] serial number A B Brand ME-1 FH-40B Active metals Mo-Co Mo-Co Content, wt% 15 20 Diameter, mm 2.0 2.0 <![CDATA[Specific surface area, m 2 ·g -1 > 170 170 <![CDATA[Pore volume, mL·g -1 > 0.38 0.45

[0036] Table 2 Properties of Crude Oil

[0037] Oil properties Catalytic gasoline <![CDATA[Density (20 °C), g·cm -3 > 0.79 Distillation range, ℃ 50～200 <![CDATA[S,μg·g -1 ]]> 793 Olefins, % 23.5 Aromatics, % 40.5 Octane number 89

[0038] Table 3 Process conditions and results

[0039] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Reactor I / Reactor 1 Pressure, MPa 0.5 0.5 0.5 1.5 1.5 Temperature, °C 180 200 220 280 280 Hydrogen-to-oil volume ratio, v / v 100 100 100 300 300 <![CDATA[Space velocity, h -1 > 5.0 5.0 5.0 3.0 5.0 Reactor II / Reactor 2 Pressure, MPa 2.5 3.0 4.0 4.0 Temperature, °C 160 170 180 260 <![CDATA[Space velocity, h -1 > 2.5 2.5 2.5 5.0 Liquefaction rate, % 40 42 43 gasoline products Olefin content, % 14.3 14.1 8.2 7.2 2.8 <![CDATA[Sulfur content, μg·g -1 > 9.6 8.6 7.1 9.3 8.5 Aromatic content, % 34.1 33.5 32.1 35.2 32.7 Octane number 97 98 96 93 92

[0040] As can be seen from Examples 1-3, the method of this invention can significantly reduce the amount of hydrogen used in the hydrogenation process. Furthermore, since the hydrogenation of aromatics in the liquid-phase reaction also consumes hydrogen, the reaction stream from reactor I does not require hydrogen recovery and recycling, eliminating the need for a costly hydrogen recycling machine. The overall reaction system has a lower hydrogen-to-oil ratio, saving hydrogen consumption. By controlling the olefin saturation in reactor I to meet standards and performing shallow desulfurization, the reacted components do not require further olefin removal. Liquefaction can be used to allow only macromolecular sulfur, alkanes, and aromatics to react further, ensuring olefin compliance while avoiding octane number loss. Simultaneously, a compressor is installed between reactors I and II to liquefy the gaseous reaction products and hydrogen from reactor I at high temperatures. Utilizing the high solubility of hydrogen at high temperatures and the low solubility of hydrogen sulfide, the pressurized liquefied macromolecular components have a high hydrogen content and low hydrogen sulfide content, optimizing the reaction environment for liquid-phase hydrogenation in reactor II and extending catalyst lifespan.

[0041] Traditional OCT-ME technology requires fractionation of the feedstock, resulting in a complex process. Furthermore, it struggles to simultaneously address aromatics removal under desulfurization conditions, leading to substandard aromatic content. Conventional fixed-bed technology, however, suffers from poor selectivity due to the lack of separate reactions between olefins and sulfides in the feedstock. This results in high olefin loss and significant octane number reduction during aromatics removal.

Claims

1. A method for producing automotive gasoline, characterized in that, include: The feedstock oil and hydrogen first enter reactor I, where a gas-phase reaction occurs. The effluent from reactor I is pressurized and partially or completely converted into a liquid phase, which then undergoes a liquid phase reaction in reactor II to ultimately produce automotive gasoline. The reaction pressure in reactor II is 0.5~3.5 MPa higher than that in reactor I. The liquefaction rate of hydrogen and feedstock oil in reactor II, i.e., the molar ratio of feedstock oil and hydrogen in liquid state to total feedstock oil and hydrogen, shall not be less than 30%; The operating conditions of reactor I include: reaction pressure 0.5~2.0MPa, hydrogen-to-oil volume ratio 80~300, and reaction temperature 100~230℃; The operating conditions of reactor II include: a reaction pressure of 2.5~4.0 MPa, a reaction temperature of 140~220℃, and a volume hourly space velocity of 1.5~3.

5. The top effluent from reactor II is a gaseous component, which passes through a heat exchanger and then enters a high-pressure separator to obtain a liquid light component. The heavy liquid components obtained from the liquid phase reaction in reactor II are discharged from the bottom of reactor II. The heavy liquid components are mixed with the light liquid components to obtain automotive gasoline. Reactor I is filled with a catalyst that has selective hydrodesulfurization and isomerization functions, and reactor II is filled with hydrorefining catalyst B.

2. The method according to claim 1, characterized in that, The effluent from the top of reactor II is a gaseous component, which passes through a condenser and then enters a high-pressure separator to obtain a liquid light component.

3. The method according to claim 1, characterized in that, The feedstock is one or more of catalytic gasoline, straight-run naphtha, and coking naphtha.

4. The method according to claim 1, characterized in that, The feedstock oil has a distillation range of 40~200℃, S≯2000μg / g, olefins≯40wt%, aromatics≯50wt%, and an octane number RON of not less than 70.

5. The method according to claim 4, characterized in that, The feedstock oil has an S content of 100~1000μg / g, an olefin content of 10wt%~25wt%, an aromatic content of 15wt%~45wt%, and an octane number (RON) of 75~90.

6. The method according to claim 1, characterized in that, The liquefaction rate of hydrogen and feedstock oil in reactor II, that is, the molar ratio of feedstock oil and hydrogen in liquid state to total feedstock oil and hydrogen, is 40%~80%.

7. The method according to claim 1, characterized in that, The properties of the gasoline used in vehicles include: octane number ≥ 95, sulfur content ≤ 10 μg·g. -1 Olefin content ≤ 15v, aromatic content ≤ 35v.

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