JP5345298B2 - Method for refining hydrocarbon oil - Google Patents

Description

  The present invention relates to a method for refining hydrocarbon oil, in particular, hydrorefining treatment of hydrocarbon oils in a lump, followed by refined light naphtha, refined heavy naphtha, refined kerosene, refined light oil and refined heavy gas oil. It is related with the refinement | purification method of the hydrocarbon oil which can manufacture light oil with low sulfur content and stable quality by isolate | separating into minutes.

  In the conventional refining process of crude oil, as shown in FIG. 1, generally crude oil is distilled at atmospheric pressure by an atmospheric distillation apparatus 1 to obtain light gas, LP gas, naphtha (light naphtha, heavy naphtha), kerosene, light oil. And the remaining oil are separated into their respective fractions. Then, after atmospheric distillation, the light gas is separated into acid gas by the amine purification device 2 to become fuel gas, while the separated acid gas is sent to the sulfur recovery device 3 to recover sulfur. Further, the separated LP gas is made into product LP gas after impurities are removed by the LP gas processing device 4.

  The light naphtha fraction is subjected to a simple treatment in the light naphtha treatment device 5 to become gasoline or a petrochemical raw material, and the heavy naphtha fraction is hydrorefined in the presence of a catalyst in the hydrorefining device 6. After the treatment, it is isomerized or aromatized in the catalytic reformer 7 to become gasoline or aromatic product. After the naphtha fraction was distilled at once from the atmospheric distillation apparatus 1, all the naphtha fractions were hydrorefined in the hydrorefining apparatus 8 for naphtha in the presence of a catalyst, then light naphtha and heavy Sometimes separated into quality naphtha.

  Further, the kerosene fraction is refined by the kerosene refining device 9 to become kerosene, and the light oil fraction is hydrorefined in the presence of a catalyst by the hydrorefining device 10 for light oil to become light oil. The residual oil remaining at the bottom of the atmospheric distillation apparatus 1 is taken out from the atmospheric distillation apparatus 1 and used as a heavy oil blending material or distilled under reduced pressure with a vacuum distillation apparatus to produce a light oil production raw material. Separated. As described above, in the conventional crude oil refining process, a refining process such as hydrorefining (desulfurization) is performed on each of the separated fractions.

  However, this method has a problem that the equipment configuration is complicated, equipment cost is high, energy efficiency is low, and operation management and maintenance are required for each device. For this reason, especially when the amount of processed crude oil is small, the apparatus configuration is further simplified, and a compact and low-cost processing method has been desired.

  From the above viewpoint, hydrotreating is performed on crude oil, a fraction obtained by removing naphtha fraction from crude oil, or a fraction obtained by removing residual oil from crude oil, and then subjected to atmospheric distillation. Methods for fractionating fractions such as naphtha fractions and kerosene fractions have been proposed.

  For example, in JP-A-3-294390 (Patent Document 1), after naphtha fraction in crude oil is distilled and separated, the remaining fraction excluding the naphtha fraction is contacted with a desulfurization catalyst to desulfurize, A method for refining crude oil that is then distilled to separate each product is described.

  Japanese Patent Laid-Open No. 7-82573 (Patent Document 2) discloses that crude oil is distilled at atmospheric pressure to separate residual oil and distillate oil, and distillate oil is collectively hydrogenated by the same hydrotreating apparatus. A method for treating petroleum to be treated is described.

  Furthermore, Japanese Patent Laid-Open No. 7-300592 (Patent Document 3) discloses that crude oil is separated into distillate and residual oil consisting of light oil and a fraction having a lower boiling point than light oil, and then distillate is hydrogenated in a lump. A method for treating petroleum is described in which a refined oil obtained by treatment is separated into desired fractions by a rectifying column, and a light oil obtained by the rectifying column is contacted with a hydrotreating catalyst to perform a decolorization treatment.

  Furthermore, Japanese Patent Application Laid-Open No. 2005-187823 (Patent Document 4) describes a method for increasing the production of kerosene / light oil with good quality and stability, and as a method for simplifying the equipment, crude oil or naphtha fraction. A method of hydrotreating crude oil, wherein the removed crude oil is collectively hydrotreated using a catalyst in which at least one kind of metal belonging to Group 6, 8, 9 or 10 of the periodic table is supported on a specific carrier. Is described.

  On the other hand, in recent years, further reduction in sulfur of kerosene and light oil has been demanded. On the other hand, for example, in order to improve the desulfurization rate and obtain a light oil having a lower sulfur content, it is effective to raise the desulfurization reaction temperature. However, when the desulfurization reaction temperature is raised, an undesirable side reaction is likely to occur, and it is difficult to obtain a light oil fraction with stable quality. Therefore, there is a demand for a method capable of obtaining kerosene / light oil having a compact apparatus, capable of low-cost processing, low sulfur content, and stable quality.

JP-A-3-294390 JP-A-7-82573 JP 7-300592 A Japanese Patent Laid-Open No. 7-305077

  Under such circumstances, the object of the present invention is to produce a petroleum fraction having a low sulfur content, good quality and stability, particularly a light oil fraction, economically advantageously using a simplified refining equipment. An object of the present invention is to provide a method for refining hydrocarbon oil.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have determined from a hydrocarbon oil in which the sulfur content in each fraction is higher in naphtha fractions than kerosene and light oil fractions, using a crude distillation apparatus. The light gas and the LP gas fraction are separated, and the remaining distillate from which the light gas and the LP gas fraction are separated are collectively hydrorefined (desulfurized), and the hydrorefined distillate is obtained. Was found to be able to obtain a fraction having a low sulfur content and a stable quality by a purification method simplified by a compact device by rectifying the desired fraction with an atmospheric distillation apparatus. I came to let you.

That is, the method for refining the hydrocarbon oil of the present invention comprises:
Sulfur content contained in naphtha fraction, having 10 vol% distillation temperature of 35-80 ° C, 95 vol% distillation temperature of 230-350 ° C and 97 vol% distillation temperature of 250-420 ° C. Separates at least light gas and LP gas from a hydrocarbon oil having a sulfur content higher than that contained in the kerosene fraction and the light oil fraction in a crude distillation apparatus,
Hydrotreating the hydrocarbon oil from which the light gas and LP gas have been separated together,
The hydrorefined refined oil is subjected to atmospheric distillation with an atmospheric distillation device, and separated into refined light naphtha, refined heavy naphtha, refined kerosene, refined light oil and refined heavy light oil.
In addition, the hydrocarbon oil is natural gas condensate, and the refined light oil separated by the atmospheric distillation apparatus is light oil having a sulfur content of 10 wtppm or less .

  In a preferred embodiment of the method for purifying hydrocarbon oil of the present invention, after the purified total naphtha is separated by the atmospheric distillation, the purified total naphtha fraction is separated into purified light naphtha and purified heavy naphtha by a naphtha separator. .

  In another preferred embodiment of the hydrocarbon oil refining method of the present invention, mercury is further adsorbed and removed from the refined light naphtha and refined heavy naphtha fraction.

  According to the present invention, a hydrocarbon oil having specific properties is used to perform a hydrotreating treatment (desulfurization) in a batch, and then separated into a desired fraction by an atmospheric distillation device. By the refining method, a fraction having a low sulfur content and a stable quality, particularly a light oil fraction, can be obtained.

  Hereinafter, the present invention will be described in detail with reference to the block diagram for explaining an example of the method for refining the hydrocarbon oil of the present invention shown in FIG.

[Raw material hydrocarbon oil]
In the hydrocarbon oil refining method of the present invention, the 10% by volume distillation temperature is 35 to 80 ° C., preferably 36 to 72 ° C., and the 95% by volume distillation temperature is 230 to 350 ° C. Has a distillation property of 200 to 350 ° C. and a 97% by volume distillation temperature of 250 to 420 ° C., preferably 250 to 400 ° C., and the sulfur content contained in the naphtha fraction obtained by atmospheric distillation is the kerosene fraction. And a hydrocarbon oil having a sulfur content higher than that contained in the light oil fraction.
In the present invention, the sulfur content contained in the naphtha fraction is greater than the sulfur content contained in the kerosene fraction and the light oil fraction. Distillation from hydrocarbons at a boiling point of 150 ° C., distillation as a kerosene fraction at a boiling point of 150 ° C. to 250 ° C., distillation as a light oil fraction at a boiling point of 250 ° C. to 360 ° C. It means that the sulfur content contained in each fraction subjected to the above is compared.
Here, the distillation apparatus refers to an apparatus that separates a liquid mixture using a difference in boiling points, and can separate a liquid or solid mixture at room temperature and normal pressure by distillation as a liquid mixture by adjusting temperature and pressure.
In general, the naphtha fraction has a boiling range of about 30 ° C. to 200 ° C., the kerosene fraction has a boiling range of about 145 ° C. to 300 ° C., and the light oil fraction has a boiling range of 170 ° C. To about 370 ° C. In the present invention, the boiling point range can be appropriately adjusted within the range not departing from the above boiling point range depending on the usage of each fraction.

In the present invention, the sulfur content contained in the naphtha fraction in the feed hydrocarbon oil is greater than the sulfur content contained in the kerosene fraction and the light oil fraction, preferably the sulfur content contained in the kerosene fraction and the light oil fraction. 3 to 800 times the minute. In addition, the sulfur content contained in the naphtha fraction in the raw material hydrocarbon oil is preferably in the range of 200 to 8000 wtppm, and the sulfur content contained in the kerosene fraction and the light oil fraction is preferably in the range of 10 to 2500 wtppm.
The batch hydrorefining process (desulfurization) in the present invention is a process of hydrotreating a fraction obtained by removing at least light gas and LP gas from a hydrocarbon oil as a raw material, so sulfur contained in each fraction. Due to the difference in the desulfurization reactivity of the minute, the desulfurization reactivity of the lighter fraction becomes higher. Therefore, when hydrocarbon oil with a lower sulfur content is used in the kerosene fraction and the light oil fraction than the naphtha fraction, the reaction temperature can be set by paying attention to the desulfurization rate of the kerosene fraction and the light oil fraction. . For example, when the reaction conditions are set for refining sulfur-free light oil (sulfur content of 10 wtppm or less), lighter fractions will have less sulfur content than light oil fractions, and quality like light naphtha and heavy naphtha Products that satisfy the required quality can be obtained even for those that require a lower sulfur content than the upper diesel oil.

The feedstock hydrocarbon oil, specifically, a natural gas condensate. Natural gas condensate is a liquid hydrocarbon at normal temperature and pressure obtained during the process of collecting and refining natural gas from a natural gas field, and is extremely light and naphtha compared to general crude oil obtained from oil fields. It is close to the property. Natural gas condensate has a light API weight of 50 or more, which is widely used in Western countries as a specific gravity of petroleum, and has a low sulfur content, so it has an API specific gravity of 20 to 50 and a sulfur content of about 0 to 3%. It is a raw material that can refine more light petroleum products such as gasoline than crude oil. Examples of natural gas condensate include, but are not limited to, South Perth condensate and Northfield condensate produced in the Middle East.

[Separation of light gas and LP gas in crude distillation equipment]
In the hydrocarbon oil refining method of the present invention, the hydrocarbon oil is sent to the crude distillation apparatus 11 and distilled at atmospheric pressure to obtain a light gas (off-gas) and LP gas, and a fraction having a higher boiling point (light naphtha). , Distillate oil consisting of heavy naphtha, kerosene, light oil, heavy light oil). In the method for purifying hydrocarbon oil according to the present invention, the raw hydrocarbon oil may be subjected to pretreatment such as dehydration, desalting, and deoxygenation before atmospheric distillation in the crude distillation apparatus 11. Here, the light gas is an exhaust gas obtained by removing hydrocarbons having 3 or more carbon atoms from refinery by-product gases such as low-boiling hydrocarbons, hydrogen, hydrogen sulfide, etc. generated from each refiner in an oil refinery plant, that is, liquefaction. It is a mixed gas mainly composed of hydrogen, hydrogen sulfide, and hydrocarbons having 1 or 2 carbon atoms (methane, ethane, etc.). LP gas is also called LPG or liquefied petroleum gas and has 3 carbon atoms. And 4 hydrocarbons, ie propane, propylene, butane, butylene, or petroleum products based on these.

[Hydro-refining treatment]
Next, in the hydrocarbon oil refining method of the present invention, the distillate oil separated by the crude distillation apparatus 11 (hydrocarbon oil from which at least light gas and LP gas have been separated and removed) are collectively treated by hydrotreating apparatus 12. For example, it is brought into contact with hydrogen (H ₂ ) in the presence of a catalyst to perform a hydrorefining treatment such as desulfurization. Here, as the hydrorefining apparatus 12, it is preferable to use a gas-liquid downward co-current reactor.

  In the hydrocarbon oil refining method of the present invention, the naphtha fraction distilled together with the LP gas in the crude distillation apparatus 11 is separated by the crude naphtha separation apparatus 13 and then sent to the hydrorefining apparatus 12 together with the distillate. A hydrorefining treatment may be performed.

  The hydrogen source used in the hydrorefining treatment is not particularly limited as long as it is a hydrogen-containing gas, but preferably has a purity of 75% or more, more preferably 80% or more. Specifically, hydrogen generated as a by-product from the catalytic reforming apparatus 14 that performs catalytic reforming treatment of purified heavy naphtha, which will be described later, can be used as the hydrogen source.

  As a catalyst for hydrorefining treatment, any catalyst that can be used in hydrotreating treatment may be used. For example, a Co—Mo based catalyst, a Ni—Mo based catalyst, a Ni—Co—Mo based catalyst, or the like may be used.

As conditions for the hydrorefining treatment, the pressure is preferably in the range of 2 to 8 MPa, particularly 5 to 8 MPa, and the temperature is preferably in the range of 280 to 380 ° C., particularly 310 to 360 ° C. , preferably H ₂ / oil ratio of 50 to 200 nm ³ / kL, particularly in the range of 100 to 200 nm ³ / kL, LHSV is 0.1～5H ^-1, especially in the range of 1～3H ^-1 Preferably there is.
Although not shown, if necessary, a part of the hydrorefined refined oil may be returned to the hydrorefining apparatus 12 and hydrotreated.

[Atmospheric distillation with atmospheric distillation equipment]
Next, in the hydrocarbon oil refining method of the present invention, the refined oil hydrotreated by the hydrotreating apparatus 12 is sent to the atmospheric distillation apparatus 15 and distilled at atmospheric pressure to produce purified LP gas and purified light naphtha. Separated into fractions of refined heavy naphtha, refined kerosene, refined gas oil and refined heavy gas oil. Here, the refined light naphtha has a boiling point of 30 ° C. or more and less than 100 ° C., the refined heavy naphtha has a boiling point of 75 ° C. or more and less than 200 ° C., and the refined kerosene has a boiling point of 145 ° C. or more and less than 300 ° C. Refined gas oil has a boiling point of 170 ° C. or higher and lower than 370 ° C., and refined heavy gas oil has a boiling point of 345 ° C. or higher.

  In this step, after the naphtha fraction is distilled at once from the atmospheric distillation apparatus 15, the entire naphtha fraction may be sent to the naphtha separation apparatus 16 to be separated into light naphtha and heavy naphtha.

  Moreover, although not shown in figure, the refined refined light oil and refined heavy gas oil which were isolate | separated may be returned to the hydrorefining apparatus 12 again, and may be hydrorefined as needed.

  By the hydrorefining and fractionation treatment as described above, as shown in FIG. 2, each fraction of light gas, LP gas, refined light naphtha, refined heavy naphtha, refined kerosene, refined gas oil, and refined heavy gas oil is obtained. can get.

  The light gas may be separated from the acid gas by the amine purifier 17 and used as a fuel gas, while the acid gas may be sent to the sulfur recovery device 18 to recover the sulfur. The LP gas separated by the above-mentioned crude naphtha separation device 13 can be used as a product gas after being separated into butane and propane after removing impurities by the LP gas processing device 19.

  Refined light naphtha can be blended into gasoline as it is, or it can be used as a raw material for an ethylene decomposition apparatus (petrotized raw material), or can be subjected to reforming treatment or sweetening treatment as necessary. The refined heavy naphtha is sent to the catalytic reforming device 14 and isomerized or aromatized by the catalytic reforming device 14, and then blended into gasoline or made into an aromatic product. The hydrogen produced as a by-product in the catalytic reforming device 14 can be sent to the hydrotreating device 12 as described above and used as a hydrogen source for hydrotreating, and the LP gas produced as a by-product can be obtained from the LP gas processing device 19. It can also be mixed with purified LP gas.

Furthermore, refined kerosene can be used as product kerosene as it is, and refined light oil can also be used as product light oil as it is. Incidentally, gas oil separated by the atmospheric distillation unit 15, the sulfur content 10wtppm following diesel fuel (sulfur-free diesel fuel) Ru der. The refined heavy gas oil can be sent to a catalytic cracking device (not shown) where it can be converted to gasoline by catalytic cracking.

  In the above-described method for refining the hydrocarbon oil of the present invention, crude oil is subjected to atmospheric distillation in a crude distillation apparatus to separate light gas, LP gas, and distillate, and the distillate is collectively hydrorefined. Compared with hydrorefining with equipment 12, the crude oil is fractionated finely by distillation and then hydrorefined for each fraction, the refinery equipment configuration is simplified, construction costs and installation Space can be reduced. Further, the apparatus configuration can be made more compact even when the crude oil processing amount is small.

[Adsorption removal of heavy metals]
The raw material hydrocarbon oil may contain a larger amount of heavy metals such as mercury than general crude oil. Therefore, a heavy metal adsorption / removal device using an adsorbent is installed for refined light naphtha, refined heavy naphtha, and in some cases refined kerosene fraction, which are fractions of hydrorefined refined oil. In particular, the adsorption and removal of mercury can be performed to further improve the quality of each purified fraction. In addition, it is preferable to install an adsorption removal apparatus (not shown) immediately after the atmospheric distillation apparatus 15. Further, an adsorbent such as activated carbon can be used to remove heavy metals by adsorption.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

In Examples and Comparative Examples, distillation properties, density, sulfur content, nitrogen content, kinematic viscosity, and mercury concentration were performed according to the following methods.
Distillation properties: JIS K2254 and JIS K2601
・ Density: JIS K2249
・ Sulfur content: JIS K2541
・ Nitrogen content: JIS K2609
・ Kinematic viscosity: JIS K2283
Mercury: Measured using an automatic mercury analyzer (SP-3D, manufactured by Japan Instruments).

(Properties of raw oil)
Table 1 shows the properties of condensate (South Perth Condensate) obtained from the South Perth gas field in Iran as general natural gas condensate, and Table 2 shows the yield and properties of each fraction. In addition, including other examples, the total yield does not reach 100% because of distillation loss.

  In addition, as general crude oil, properties of Middle Eastern Marban crude oil (MU) and Kuwait crude oil (KU) are shown in Table 3, and yield and sulfur content of each fraction are shown in Table 4.

  From Tables 1 to 4, South Perth Condensate has more sulfur in the naphtha fraction than the sulfur in the kerosene and light oil fractions, while general crude oil has the sulfur content in the naphtha fraction. Is found to be less than the sulfur content in the kerosene and light oil fractions.

(Comparative Example 1)
Uses mixed crude oil (Murban crude oil (MU): Kuwait crude oil (KU): Arabian light: Arabian heavy: Others = 20: 14: 12: 12: 42 (vol%)) as raw material oil It was. Table 5 shows the properties of the mixed crude oil used, and Table 6 shows the yield of each fraction.

  Using the above mixed crude oil, each fraction was distilled and separated by an atmospheric distillation apparatus, and then each fraction was supplied to a hydrorefining apparatus and hydrorefined. Table 7 summarizes the conditions for hydrotreating each fraction and the properties of each purified fraction obtained.

  From Table 7, it can be seen that the desulfurization reaction temperature must be increased in order to obtain low sulfur gas oil. In this case, undesirable side reactions are likely to occur, and there is a problem that it is difficult to obtain a light oil fraction with stable quality.

Example 1
The above-mentioned South Perth condensate was used as a feedstock from continuous distillate (all distillate from liquid hydrocarbons at normal temperature and normal pressure with C5 carbon number) from which light gas and LP gas were removed by atmospheric distillation. . A downward cocurrent reactor filled with 10 cc of a commercially available Co—Mo catalyst in a reactor having an inner diameter of 10 mm and a length of 300 mm was used. Hydrogen purity: 100%, pressure: 5 MPa, temperature: 310 ° C., H ₂ / Oil ratio: 200 Nm ³ / kL, LHSV: 3.0 h ⁻¹ The continuous fractions from light naphtha were collectively hydrorefined under the reaction conditions.

  The refined oil after the hydrorefining treatment was transferred to a fractionator and distilled at atmospheric pressure, and separated into light naphtha, heavy naphtha, kerosene and light oil fractions, and the residual sulfur concentration of each fraction was measured. As a result, the residual sulfur concentration of each fraction was light naphtha: 0.1 wtppm, heavy naphtha: 0.1 wtppm, kerosene: 4 wtppm, diesel oil: 9 wtppm, and comparative examples in which each fraction was individually hydrotreated. Nothing inferior to one.

(Example 2)
The above-mentioned South Perth condensate was used as a feedstock from continuous distillate (all distillate from liquid hydrocarbons at normal temperature and normal pressure with C5 carbon number) from which light gas and LP gas were removed by atmospheric distillation. . A downward co-current reactor filled with 15 cc of a commercially available Ni—Co—Mo catalyst in a reactor having an inner diameter of 10 mm and a length of 500 mm was used. Hydrogen purity: 100%, pressure: 5 MPa, temperature: 320 ° C., H ₂ / Oil ratio: 160 Nm ³ / kL, LHSV: 2.0 h ⁻¹ The continuous fractions from light naphtha were subjected to hydrorefining treatment in a lump.

  The refined oil after the hydrorefining treatment was transferred to a fractionator and distilled at atmospheric pressure, and separated into light naphtha, heavy naphtha, kerosene and light oil fractions, and the residual sulfur concentration of each fraction was measured. As a result, the residual sulfur concentration of each fraction was light naphtha: 0.1 wtppm or less, heavy naphtha: 0.1 wtppm or less, kerosene: 3 wtppm, diesel oil: 8 wtppm, and each fraction was individually hydrotreated. It was not inferior to that of Comparative Example 1.

  From these results, it can be seen that according to the present invention, the apparatus configuration for oil refining is greatly simplified, and the hydrotreating effect comparable to the conventional one can be obtained.

It is a block diagram for demonstrating an example of the refinement | purification method of the conventional hydrocarbon oil. It is a block diagram for demonstrating an example of the refinement | purification method of the hydrocarbon oil of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,15 Atmospheric distillation apparatus 2,17 Amine refining apparatus 3,18 Sulfur recovery apparatus 4,19 LP gas processing apparatus 5 Light naphtha processing apparatus 6,8,10,12 Hydrotreating apparatus 7,14 Catalytic reforming apparatus 9 Kerosene refining equipment 11 Coarse distillation equipment 13 Coarse naphtha separation equipment 16 Naphtha separation equipment

Claims (3)

Sulfur content contained in naphtha fraction, having 10 vol% distillation temperature of 35-80 ° C, 95 vol% distillation temperature of 230-350 ° C and 97 vol% distillation temperature of 250-420 ° C. Separates at least light gas and LP gas from a hydrocarbon oil having a sulfur content higher than that contained in the kerosene fraction and the light oil fraction in a crude distillation apparatus,
Hydrotreating the hydrocarbon oil from which the light gas and LP gas have been separated together,
A method for purifying a hydrocarbon oil, wherein the hydrorefined refined oil is subjected to atmospheric distillation with an atmospheric distillation apparatus, and separated into refined light naphtha, refined heavy naphtha, refined kerosene, refined gas oil, and refined heavy gas oil. Because
The hydrocarbon oil is a natural gas condensate, and the refined light oil separated by the atmospheric distillation apparatus is a light oil having a sulfur content of 10 wtppm or less .   2. The hydrocarbon oil according to claim 1, wherein after separation of the purified whole naphtha by the atmospheric distillation, the purified whole naphtha fraction is separated into a refined light naphtha and a refined heavy naphtha by a naphtha separator. Purification method.   The method for purifying hydrocarbon oil according to claim 1 or 2, wherein mercury is further adsorbed and removed from the refined light naphtha fraction and the refined heavy naphtha fraction.

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