JPH07197040A - Method for improving quality of petroleum distillate - Google Patents

Abstract

PURPOSE:To improve the quality of a petroleum distillate at a low cost and to obtain an oil with a low sulfur content and a good hue. CONSTITUTION:A petroleum distillate is hydrogenated in the presence of a hydrogenation catalyst to give an oil With a sulfur content of 0.4wt.% or lower and a Saybolt color of -10 or lower, which is brought into contact with a porous material.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for improving the quality of petroleum distillates.

[0002]

In order to improve the quality of petroleum distillates, it is known to remove the sulfur content contained therein by hydrotreating. This hydrotreatment is conventionally 40 kg
It is carried out at a temperature lower than 350 ° C. under a pressure of / cm ² or less. However, in such conventional hydrotreating,
There is a limit to the reduction of sulfur, and there is a problem that when the reaction temperature is raised to improve the desulfurization rate, the hue of the obtained treated oil is significantly deteriorated. Therefore, in order to reduce the sulfur content of the petroleum distillate without deteriorating the hue thereof, a method of treating the petroleum distillate in a two-stage hydrotreatment process has been proposed (JP-A-3-86793 and JP-A-5-79793). -39492
No. 5-78670). Although these methods can obtain a product having a small amount of sulfur and a good hue, since the two-stage hydrotreatment process is adopted, the treatment cost is high and it is still not satisfactory from the economical point of view. Absent.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for economically improving the quality of petroleum distillates and obtaining a product having a low sulfur content and a good hue.

[0004]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, according to the present invention, a petroleum distillate is hydrotreated in the presence of a hydrotreating catalyst in order to remove the sulfur content contained therein, and the sulfur content is 0.4% by weight.
A method for improving the quality of a petroleum distillate, which comprises producing a hydrotreated oil having a Saybolt color value of -10 or less and then contacting the obtained hydrotreated oil with a porous substance. To be done.

The feedstock used in the present invention is a petroleum distillate containing sulfur, and is a distillate of fluid catalytic cracking (FCC) oil as well as a distillate obtained by atmospheric distillation or vacuum distillation of crude oil.
Distillates of pyrolysis oil and the like can be mentioned. These petroleum distillates are used alone or in the form of a mixture. The preferred feedstock oil used in the present invention is petroleum distillate used as automobile diesel oil, etc., and is 150 to 400 ° C., preferably 200 to 3
It has a distillation property of 40 ° C. These petroleum distillates contain sulfur content, which is usually less than 0.
It is in the range of 1 to 2% by weight, preferably 0.8 to 1.2% by weight. Of course, depending on the petroleum distillate, there are those having a sulfur content higher or lower than the above range, but the petroleum distillate used in the present invention may be any petroleum distillate.

According to the invention, the feedstock is treated in two different treatment steps in order to remove the sulfur content contained therein. That is, in the present invention, the hydrotreating step is adopted as the first step. In this hydrotreatment step, in order to remove the sulfur content in the feedstock at a high desulfurization rate, the sulfur content is as low as 0.4% by weight or less and the sulfur content is low. When the color value is -10 or less, a hydrotreated oil having deteriorated hue is generated. In the present invention, an adsorption treatment step using a porous substance is adopted as the second step treatment step. In this adsorption treatment step, substances that cause hue deterioration in the hydrotreated oil obtained in the hydrotreatment (hue-deteriorating substances) are removed, and the Saybolt color value is 0 or more, preferably 5 or more,
More preferably, it produces a treated oil that is enhanced to 15 or more. By such a two-step treatment process, it is possible to obtain a product having a good hue from a petroleum distillate while having a low sulfur content.

Next, the processing steps at each stage used in the present invention will be described. (First stage) The treatment process of the first stage comprises a hydrogenation treatment process. The main purpose of this hydrotreating step is to reduce the sulfur content of the feedstock oil with the by-production of the hue deteriorating substance as described above. The temperature is usually 280 to 480 ° C, preferably 300 to 400 ° C.
The temperature is more preferably 330 to 380 ° C., and the pressure is usually 5 to 100 kg / cm ² , preferably 10 to 80 k.
g / cm ² , and more preferably 15 to 40 kg / cm ² . Liquid hourly space velocity (LHSV) is usually 0.5 to 10 h
r ^-1 , preferably ¹ to 8 hr ^-1 , more preferably 2.0.
To 4.0 hr ^-1 , and the hydrogen gas / feed oil ratio is usually 50 to 450 m ³ / kl, preferably 80 to 160.
m ³ / kl. Conventionally known hydrotreating catalysts include, for example, V, Mo, W, Ni, and
A material carrying a hydrogenation-active metal species such as Co, Pd, Pt, Re, Ru, Rh is used. As the porous carrier, alumina, silica, titania, boria, zirconia, alumina silica, alumina titania, alumina boria, alumina zirconia, silica magnesia and the like are used. In particular, Ni-Mo and Co-supported on alumina
The use of catalysts such as Mo, Ni-Co-Mo, Ni-W is preferred. The hydrogenation-active metal supported on the carrier can be in the form of metal, oxide, sulfide or the like.
The amount of each active metal in the total catalyst is 1 to 30% by weight, preferably 3 to 22% by weight as an oxide.

In this hydrotreatment step, the sulfur content in the petroleum distillate is removed at a high rate. In this step, the sulfur content in the hydrotreated oil obtained is 0.4% by weight or less, preferably 0.2% by weight or less, more preferably 0.05% by weight or less.
It is carried out so as to have a low sulfur content of not more than wt%. When the sulfur content contained in petroleum distillates is reduced to a high sulfur content with a high desulfurization rate by such a hydrotreating step, a hue-deteriorating substance is by-produced and the hue of the resulting hydrotreated oil is Bolt color value, usually -10 or less, especially-
It was deteriorated to 15 or less. In the present invention, the hydrotreated oil containing such a hue deteriorating substance is subjected to stripping treatment as it is or if necessary to remove light components in the hydrotreated oil, and then to the second stage adsorption treatment step. Attached. In the case of the present invention, the boiling point range in the hydrotreated oil is 2
It is preferred to separate the fractions below 50 ° C, preferably below 300 ° C, by stripping. According to the research conducted by the present inventors, the light fraction separated by this stripping has a good hue, and the hue is as high as a Saybolt color value of 10 or more, and can be directly used as a product. is there. Moreover, when the light fraction is separated in such a manner, the amount of the hydrotreated oil sent to the adsorption process of the second stage is reduced, which has an advantage of reducing the processing load of the second stage.

(Second stage) The second stage treatment is an adsorption treatment process in which a porous substance is used as an adsorbent, and the hue deteriorated substance is adsorbed and removed from the hydrotreated oil having a deteriorated hue obtained in the first stage. , A step of obtaining a product with improved hue. As the adsorbent, porous materials such as silica, alumina, magnesia, titania, activated carbon, activated clay, zeolite, solid acid substances and mixtures thereof are used. Generally, the average pore size is 3 to 1000Å, preferably 5 to 30
0Å porous material is used. The surface area is 5
It is 0 m ² / g or more, preferably 100 m ² / g or more. Examples of the solid acid include silica-alumina, silica-magnesia, silica-titania, alumina-magnesia, alumina-zirconia, alumina-titania, alumina-boria, silica-alumina-magnesia, silica-alumina-zirconia and the like. As for the acid property, it is preferable that the total amount of acid in the baked product is 0.05 to 1.0 mmol / g and the ratio of the strong acid is 5 to 70%. The total acid amount and the strong acid amount in the present specification are measured as follows. (Measurement of total acid amount and strong acid amount) 1 g of sample is 400 ° C., 1 ×
After keeping under the condition of 10 ⁻⁴ Torr for 4 hours, ammonia gas is adsorbed, the heat of adsorption generated at that time is measured, and the amount of adsorbed ammonia is measured from the heat of adsorption. The amount of strong acid was calculated. In this case, the amount of acid having an adsorption heat of 70 ki / mol or more was taken as the total acid amount, and the amount of acid having an adsorption heat of 95 kj / mol or more was taken as the strong acid amount. As the zeolite, various conventionally known crystalline silicates, for example, crystalline aluminosilicate, crystalline silicalite,
Examples thereof include alumino metallosilicates (for example, crystalline aluminogallosilicates) containing a metal in the skeleton structure. As cations in zeolite, hydrogen,
Examples thereof include alkali metals, alkaline earth metals and rare earth metals. The average pore size of zeolite is 3 to 20.
Å, preferably 5 to 18Å.

The adsorbent used in the present invention is preferably a mixture of zeolite and a solid acid substance. As the solid acid substance, use of silica-alumina is particularly preferable. In this case, the content of zeolite is 10 in the mixture.
˜50 wt%, preferably 20-40 wt%. Such a mixture is used as a catalyst composition for fluid catalytic cracking (FCC) of heavy oil, but in the present invention, a commercially available FCC catalyst composition can be used as an adsorbent. Further, in the present invention, the used FCC catalyst composition can be advantageously used as an adsorbent. This used F
The CC catalyst composition has a composition of 450-7 in air.
Heating to a temperature of 00 ° C, preferably 550 to 600 ° C,
By removing the carbonaceous material contained in the catalyst composition by combustion, the catalyst taken out from the regeneration tower of the FCC can be advantageously used as it is as the adsorbent in the present invention.

The adsorption treatment of the hydrotreated oil obtained in the first stage hydrotreatment step is carried out by bringing the hydrotreated oil into contact with an adsorbent. Adsorption treatment temperature is 2
It is 0 to 250 ° C, preferably 30 to 200 ° C. The operation pressure of the adsorption treatment is 0 to 100 kg / cm ² G, preferably ^{2 to} 50 kg / cm ² G. Generally, conditions of temperature and pressure for holding the hydrotreated oil in the liquid phase are adopted. The contact time is 0.1 to 100 minutes, preferably 1 to 60 minutes. The system of the adsorption bed in which the hydrotreated oil and the adsorbent are brought into contact with each other can be various systems such as a fixed bed, a suspension bed and a boiling bed.

In the adsorption treatment of the hydrotreated oil according to the present invention, the hue deteriorating substance in the hydrotreated oil is adsorbed and removed by the adsorbent. According to the study by the present inventors, this hue deterioration substance is a new by-product of the hydrotreatment process,
Although it is composed of a polycyclic aromatic compound that is not originally contained in petroleum distillate that is a feedstock oil, its content is very small, and it is usually a trace amount of 5 wtppm or less in hydrotreated oil, It was found that the adsorbent can be efficiently removed by adsorption. This adsorption treatment step is different from the hydrotreatment step that requires high temperature and high pressure, and can be carried out by a simple apparatus. Therefore, the treatment cost is generally low, and in the case of the present invention, adsorption removal should be performed. Since the content of the hue deteriorating substance is very small, the purpose can be sufficiently achieved by using a small device. This adsorption treatment makes it possible to obtain a product oil having a good Saybolt color value of 0 or more, particularly 5 or more.

Next, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a flow sheet for one preferred embodiment of the present invention. In FIG. 1, 1 is a hydrotreating apparatus, 2 is a gas-liquid separator, 3 is a stripper, 4 is an adsorption tower, 4'is a switching adsorption tower, 5 is a heating furnace, and 7 and 20 are heat exchangers. In FIG. 1, the feedstock oil is introduced into the heating furnace 5 along with the hydrogen gas from the line 9 through the line 8 and the pump 6, and further through the heat exchanger 7 and the line 10, and after being heated to a predetermined temperature here. ,
It is introduced into the hydrotreating apparatus 1 and undergoes hydrotreating. The mixture of hydrotreated oil and hydrogen gas extracted from the hydrotreatment device 1 through the line 11 passes through the heat exchanger 7,
Here, heat is exchanged with the raw oil, and after being cooled to a predetermined temperature, it is introduced into the gas-liquid separator 2, where it is gas-liquid separated. The separated gas components are used as off gas in the line 12
Is discharged through. On the other hand, for hydrotreated oil, line 1
3 is introduced into the stripper 3 through which the light components are separated through line 14 and the hydrotreated oil is separated through line 1.
It is pulled out through 5. Stripper 3 to line 15
The hydrotreated oil withdrawn through is introduced into the heat exchanger 16, where it is cooled to a predetermined temperature by heat exchange with the cooling medium introduced into the heat exchanger 16 through the line 17. Then, it is introduced into the adsorption tower 4 through the valve 18.
In the adsorption tower 4, the hue deteriorating substance in the hydrotreated oil is adsorbed and removed. High-quality product oil with a small amount of sulfur and a good hue is extracted from the adsorption tower 4 through the valve 19 and the line 22. Reference numeral 4'denotes an adsorption tower for switching, and when the adsorption tower 4 reaches saturated adsorption, the hydrotreated oil passing through the line 15 is treated in this adsorption tower by a valve operation, and the adsorption tower 4 is in between. Is subjected to reproduction processing.

The adsorption tower 4 is of a fixed bed type packed with a pellet-shaped adsorbent, and its operating temperature is 20 to 2
50 ° C., preferably 30-200 ° C., operating pressure 0-100 kg / cm ² G, preferably 2-50 kg /
cm ² G. Also, its liquid hourly space velocity (LHSV)
Is 0.5 to 600 hr ^-1 , preferably 1.0 to 100
It is hr ^-1 .

[0015]

According to the present invention, by adopting the combination of the hydrotreating step and the adsorption treating step, it is possible to economically produce a high-quality product oil having a low sulfur content and a good hue from a petroleum distillate. You can get well. INDUSTRIAL APPLICABILITY The method of the present invention is advantageously applied as a production process of a light oil for automobiles which requires a low sulfur content.

[0016]

EXAMPLES Next, the present invention will be described in more detail by way of examples.

Examples 1 and 2 As raw material oil, a mixed oil of 90% by weight of straight-run light oil and 10% by weight of cracked light oil was used. Specific gravity of this mixed oil (15/4
C.) was 0.853, and the sulfur content was 1.06% by weight. The distillation start point of this mixed oil was 202 ° C, and the distillation end point was 362 ° C. The feedstock oil was subjected to a two-stage treatment consisting of hydrogenation treatment and adsorption treatment according to the flow shown in FIG. Table 1 shows the processing conditions and the processing results.

In the above process, the gas-liquid separator 2
The operating conditions of the stripper 3 and the stripper 3 are as follows. (Gas-liquid separator 2) (1) Gas-liquid separation temperature: 230 ° C (2) Gas-liquid separation pressure: 13 kgG / cm ² (stripper 3) (1) Tower top temperature: 200 ° C (2) Tower top pressure: 2 Atmospheric pressure (3) Light fraction removal rate: 38 wt% (vs. hydrogenated oil) (4) Light fraction properties Saybolt color value: +30 Sulfur content: 0.04 wt%

The specific contents of the adsorbents A and B shown in Table 1 are as follows. (Adsorbent A) Molecular sieve 13X (particle size 1.6
mm, pore diameter 10Å) (Adsorbent B) FCC waste catalyst (specific surface area 162 m ² /
g, pore volume 0.3 ml / g)

[0020]

[Table 1] * 1 H ₂ gas amount (m ³ ) per 1 kl of feed oil

[Brief description of drawings]

FIG. 1 shows a flow sheet for one embodiment of the present invention.

[Explanation of symbols]

 1 Hydrotreating device 2 Gas-liquid separator 3 Stripper 4 Adsorption tower 4'Adsorption tower (for switching) 5 Heating furnace 7, 20 Heat exchanger

Claims (2)

[Claims] 1. A petroleum distillate is hydrotreated in the presence of a hydrotreating catalyst to remove the sulfur content contained therein, and the sulfur content is 0.4% by weight or less. A method for improving the quality of petroleum distillates, which comprises producing a hydrotreated oil having a value of -10 or less, and then contacting the obtained hydrotreated oil with a porous substance. 2. The method according to claim 1, wherein the porous material is a waste catalyst comprising a zeolite obtained from a fluid catalytic cracking step and a solid acid material.