JP2000256676A - Distillation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cracked gas oil having desired sulfur content and cetane index by distilling a cracked oil obtained by subjecting a topped crude to a hydrogenation treatment including at least hydrocracking so as to satisfy specified conditions. SOLUTION: The distillation is conducted so as to satisfy formulas 1: B>=278.5 Y/(0.194XX+0.072YY-0.017A+43.6)-65.7 and formula 2: C<=26.5X/(-12.0 XX-8.0YY+1.1A+1,264.0)+332.9. In the formulas, A ( deg.C) is the 5 wt.% distillation point of the topped crude; XX (wt.%) is the decomposition ratio for fractions of 343 deg.C or higher in the topped crude; YY (wt.%) is the desulfurization ratio of the topped crude; B ( deg.C) is the 5 wt.% distillation point of the cracked gas oil; C ( deg.C) is the 95 wt.% distillation point of the cracked gas oil; X (wt.ppm) is the desired sulfur content of the cracked gas oil; and Y (dimensionless) is the desired cetane index of the cracked gas oil, provided that the formulas: XX>=35, 240>=B>=160, 370>=C>=280 and C-B>=60 are satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing cracked gas oil by hydrocracking heavy oil, in particular, atmospheric residual oil.

[0002]

2. Description of the Related Art As the air pollution in urban areas has become more serious, the regulation value of sulfur content in diesel gas oil has been reduced from 2000 ppm to 500 ppm in Japan since 1997. However, regulations on sulfur content in diesel oil in Europe and the United States have been reduced to 50 ppm since 2005, and regulations in Japan will be more stringent than at present. In response to these regulations, the petroleum industry has been tackling the urgent and serious problem of establishing a technology for producing low-sulfur gas oil base materials without making major equipment modifications.

[0003] Among the cracked oils obtained by hydrocracking and desulfurizing normal pressure residual oils, it is said that high boiling fractions contain sulfur compounds remaining without being desulfurized due to their difficulty in desulfurization. Have been done. The sulfur content of the cracked gas oil fraction is also mainly contained in the high boiling fraction, and the sulfur content of the cracked gas oil can be reduced by lowering the boiling point when the cracked oil is distilled to obtain the cracked gas oil. However, when the boiling point is lowered, the sulfur concentration in the cracked gas oil decreases, but as the boiling point of the cracked gas oil decreases, the cetane index tends to decrease. Therefore, it was difficult to obtain a cracked gas oil that satisfies both the sulfur concentration and the cetane index performance without distillation in an appropriate boiling point range. At best, this was adjusted based on past experience and trial and error with the same cracked oil.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a method for easily producing a well-balanced high-quality cracked gas oil from a hydrocracked oil obtained from an atmospheric residue. It is an object.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that cracking obtained by subjecting a normal pressure residual oil to a hydrotreating process including at least hydrocracking. When producing cracked gas oil by distilling from oil, 5% by weight distillation point, 95% by weight distillation point, etc. of the desired crude oil residual pressure and the produced cracked gas oil with respect to the target sulfur concentration and target cetane index of the desired cracked gas oil, respectively It has been found that the above problem can be solved when satisfies a special correlation formula, and the present invention has been completed.

That is, the gist of the present invention is as follows. [1] The following formulas (1) and (2) are obtained from a cracked oil obtained by subjecting a normal pressure residual oil to a hydrotreating process including at least hydrocracking.
To produce cracked gas oil by distillation to satisfy the above. B ≧ 278.5Y / (0.194XX + 0.072YY−0.017A + 43.6) −65.7 (1) C ≦ 26.5X / (-12.0XX−8.0YY + 1.lA + 1264.0) ) +332.9 (2) where A (° C.): 5% by weight distillation point of raw material residual pressure XX (% by weight): Decomposition of 343 ° C. or higher fraction in raw material residual pressure residual oil YY (% by weight): Desulfurization rate of raw pressure residual oil B (° C.): Distillation point of 5% by weight of cracked gas oil C (° C.): Distillation point of 95% by weight of cracked gas oil X (weight ppm): of cracked gas oil Target sulfur concentration Y (dimensionless): Indicates the target cetane index of cracked gas oil.

However, XX ≧ 35 240 ≧ B ≧ 160 370 ≧ C ≧ 280 CB ≧ 60. [2] Hydrotreating including hydrocracking involves hydrodemetallation,
[1] The method for producing cracked gas oil according to [1], which includes hydrotreating of hydrocracking and hydrodesulfurization.

[0008]

Embodiments of the present invention will be described below. The present invention relates to a method for producing a cracked gas oil by distilling a cracked oil obtained by subjecting a heavy oil, particularly an atmospheric residue to a hydrotreating process including at least hydrocracking under specific conditions. Therefore, the hydrotreating method will be described first. The hydrogenation treatment may be any treatment that includes hydrocracking, and it is preferable that the treatment further includes hydrodesulfurization treatment or that includes each hydrotreatment of hydrodemetallation and hydrodesulfurization. In particular, a method in which hydrodemetallation, hydrocracking, and hydrodesulfurization are performed in this order, or hydrodemetallation, hydrodesulfurization, and hydrocracking are performed in this order is preferable. Furthermore, depending on the type of catalyst, these treatments may be performed simultaneously. For example, desulfurization and demetallation or decomposition and desulfurization often proceed in the presence of the same catalyst.

The heavy oil used as a raw material is a normal pressure residual oil,
Vacuum resid, vacuum gas oil, heavy gas oil and crude oil, or a mixture thereof. Among them, atmospheric residual oil is mentioned as a particularly suitable raw material oil. A typical example is the use of atmospheric residual oil as a heavy oil, and the production method of the present invention for producing cracked gas oil in the order of hydrodemetallation, hydrodesulfurization, hydrocracking, and distillation is performed for each step. explain. The following description can also be applied to a case in which another heavy oil is used as a feedstock oil and the cracked oil obtained by the above-described other hydrogenation treatment is similarly distilled to produce a cracked light oil.

(1) Hydrodemetallization Step The feedstock used in the present invention is preferably an atmospheric residual oil obtained from atmospheric distillation of crude oil. The mixture obtained by mixing the atmospheric residual oil and hydrogen gas is first used in the first reaction step.
It is sent to a stage, a hydrodemetallization step. The hydrodemetallization step comprises one or more reaction towers. In the case of a fixed bed, each reaction tower is usually divided into a plurality of catalyst beds, and a fluid (usually hydrogen gas) for cooling a reactant is introduced into each catalyst bed. The catalyst used for this hydrodemetallization treatment may be the one usually used for hydrodemetallization treatment. That is, a porous inorganic oxide such as alumina, silica, silica-alumina or sepiolite is used as a carrier, and a metal or a metal compound of Group 5, 6, 8, 9 and 10 of the periodic table (hereinafter sometimes simply referred to as metal). ), One or more of which are supported in an oxide state can be used. The conditions of the hydrodemetallization treatment are as follows: a reaction temperature of 300 to 450 ° C., a hydrogen partial pressure of 30 to 200 kg /
cm ² G, hydrogen / oil ratio 300-2,000 Nm ³ / k
1, LHSV (liquid hourly space velocity) 0.1 to 10 hr ^-1 , preferably 360 to 420 ° C., hydrogen partial pressure 100 to 100
180 kg / cm ² G, hydrogen / oil ratio 500-1,000
Nm ^{3 /} kl, LHSV 0.3 to 5.0 hr ⁻¹ .

(2) Hydrocracking Step The treated oil treated in the hydrodemetallizing step is then sent to the hydrocracking step. The hydrocracking step comprises one or more reaction towers. And in the case of a fixed bed, each reaction tower is usually divided into a plurality of catalyst beds, and a fluid (usually hydrogen gas) for cooling a reactant is introduced into each catalyst bed. The catalyst used in the hydrocracking step is disclosed in
49131, JP-A-61-24433, JP-A-3-21
484 and the like can be used. That is, iron-containing zeolite 2
A carrier comprising 0 to 80% by weight and 80 to 20% by weight of an inorganic oxide is obtained by supporting one or more metals belonging to Groups 6, 8, 9 and 10 of the periodic table in an oxide state. . Further, a carrier comprising 10 to 90% by weight of an iron-containing zeolite and 90 to 10% by weight of an inorganic oxide prepared by the technique disclosed in Japanese Patent Application Laid-Open No. 2-289419 is provided on the periodic table Nos. 6, 8, 9 and 10. It is also possible to use one in which one or more of the metals of the group are supported in the form of an oxide. When the iron-containing aluminosilicate obtained by treating the latter steam-treated iron-containing steaming zeolite with an aqueous iron salt solution is used, the effect of reforming the gas oil fraction is high and effective. The conditions for the hydrocracking treatment are as follows:
４５０450 ° C., hydrogen partial pressure 30〜200 kg / cm ² G, hydrogen / oil ratio 300〜2,000 Nm ³ / kl, LHSV
(Liquid hourly space velocity) 0.1-2.0 hr ^-1 , preferably 380-420 ° C., hydrogen partial pressure 100-180 kg
/ Cm ² G, hydrogen / oil ratio 500-1,000 Nm ³ / k
1, LHSV 0.2 to 1.0 hr ^-1 .

(3) Hydrodesulfurization Step The product oil from the hydrocracking step which has been subjected to hydrodemetallization treatment and then hydrocracked is further sent to the hydrodesulfurization step. The hydrodesulfurization step comprises one or more reaction towers. In the case of a fixed bed, each reaction tower is usually divided into a plurality of catalyst beds, and a fluid for cooling the reactants is introduced into each catalyst bed. The catalyst used in the hydrodesulfurization step may be the one usually used in heavy oil hydrodesulfurization treatment. That is, a carrier of alumina, silica, zeolite, or a mixture thereof, or the like may be used in the Periodic Table No. 5, 6, 8, 9
Among them, a metal in which one or more of the metals belonging to Group 10 are supported in an oxide state can be used. The conditions for this hydrodesulfurization treatment are as follows:
0 ° C., hydrogen partial pressure 30 to 200 kg / cm ² G, hydrogen / oil ratio 300 to 2,000 Nm ³ / kl, LHSV (liquid hourly space velocity) 0.1 to 2.0 h ⁻¹ , preferably reaction temperature 36
0-420 ° C, partial pressure of hydrogen 100-180kg / cm
² G, hydrogen / oil ratio 500-1,000 Nm ³ / kl, L
HSV is 0.1 to 0.5 hr ^-1 .

(4) Separation Step As described above, the product oil that has gone through the reaction step after the completion of the hydrodemetallation, hydrocracking, and hydrodesulfurization is treated in a plurality of separation tanks to form a gas part and a liquid part. Is separated into
Among them, the gas portion can be subjected to a treatment such as an increase in hydrogen purity after removing hydrogen sulfide, ammonia and the like, mixed with a new supply hydrogen gas and recycled to the reaction process. On the other hand, the liquid part separated in the separation step is cracked oil and is introduced into the next distillation step.

(5) Distillation Step The cracked oil separated in the separation step is introduced into the distillation step and separated into each fraction. This distillation may be performed by atmospheric distillation or vacuum distillation. The present inventors have studied the properties of cracked gas oil, in particular, the distillation properties of cracked gas oil obtained as a method for making the sulfur concentration or cetane index of cracked gas oil the desired property. In the case of the cetane index, it has been found that it is effective to carry out distillation using a 5% distillation point as a control index. Furthermore, it has been found that it is effective to combine the 5% distillation point of the raw heavy oil, the cracking rate of the raw heavy oil, and the desulfurization rate of the raw heavy oil as a management index for the distillation of the cracked oil. Specifically, in the present invention, the distillation point of 5% by weight of the cracked gas oil obtained by distillation is defined as B
When the distillation point at 95 ° C. and 95% by weight is C ° C., it is necessary to produce cracked gas oil by distillation so as to satisfy the following formulas (1) and (2). B ≧ 278.5Y / (0.194XX + 0.072YY−0.017A + 43.6) −65.7 (1) C ≦ 26.5X / (-12.0XX−8.0YY + 1.lA + 1264.0) ) +332.9 (2) where A (° C.): 5% by weight distillation point of raw material residual pressure XX (% by weight): Decomposition of 343 ° C. or higher fraction in raw material residual pressure residual oil YY (% by weight): Desulfurization rate of raw pressure residual oil B (° C.): Distillation point of 5% by weight of cracked gas oil C (° C.): Distillation point of 95% by weight of cracked gas oil X (weight ppm): of cracked gas oil Target sulfur concentration Y (dimensionless): Indicates the target cetane index of cracked gas oil.

However, XX ≧ 35 240 ≧ B ≧ 160 370 ≧ C ≧ 280 CB ≧ 60.

In the present invention, each distillation temperature (distillation point of 5% by weight, etc.) in the distillation of atmospheric residual oil and cracked gas oil is AS
Specified in a distillation test according to TM D2887. The cetane index is specified by ASTM D4337. The cracking rate XX (% by weight) of the fraction of 343 ° C. or higher in the raw material heavy oil is XX = 100 × ｛100− (343 ° C. in the cracked gas oil).
The yield of the above fraction wt%) / (the yield of the fraction of 343 ° C. or higher in the feed oil, wt%).

When the 5% by weight distillation point of the cracked gas oil does not satisfy the formula (1), the cetane index of the cracked gas oil falls below the target value Y. When the 95% by weight distillation point does not satisfy the formula (2), the sulfur concentration of the cracked gas oil exceeds the target value X. Therefore, the cracked gas oil may be distilled by adjusting the conditions such as the temperature of the distillation column so that B and C satisfy the above equations (1) and (2). When B is made extremely larger than the right side of the above formula (1), and when C is made extremely smaller than the right side of the above formula (2), it is possible to obtain cracked gas oil even if each requirement of the present invention is satisfied. It is not preferable because the rate decreases. XX ≧ 35, 240 ≧ B ≧ 16 from the viewpoint of producing cracked gas oil having ordinary distillation properties and cetane index.
0, 370 ≧ C ≧ 280 and CB ≧ 60 must be satisfied.

[0018]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. As the raw material oil, two types of normal pressure residual oils A and B obtained by normal pressure distillation of Arabian heavy crude oil were used. Table 1 shows the properties.

Example 1 From the upstream side of a 100 cc fixed bed flow reactor, 21% by volume of a hydrodemetallation catalyst, 26% by volume of a hydrocracking catalyst, and 43% by volume of a hydrosulfurization catalyst were charged in this order. Then, a hydrogenated treatment was carried out using Arabian Heavy Atmospheric Residue A as a raw material to obtain a cracked oil. As each hydrotreating catalyst, a catalyst shown in Table 2 was used. The processing conditions for the entire hydrotreating were a hydrogen partial pressure of 140 kg / cm ² G, a hydrogen / oil ratio of 900 Nm ³ / kl, and an LHSV of 0.15 hr ^-1.
And The reaction temperature was 405 ° C. for the hydrodemetallation catalyst layer, 400 ° C. for the hydrocracking catalyst layer, and 395 ° C. for the hydrodesulfurization catalyst layer.
And At this time, the desulfurization rate was 93% by weight, and the decomposition rate of the fraction at 343 ° C. or higher was 41% by weight.

In order to obtain the cracked gas oil by distilling the cracked oil obtained above, the target sulfur concentration of the cracked gas oil is set to 400 wt.
m and the target cetane index were set to 50. In this case, it is calculated that the 5% by weight distillation point ≧ 197 ° C. and the 95% by weight distillation point ≦ 362 ° C. of the cracked gas oil produced from the formulas (1) and (2) are required. Therefore, 5% by weight of the distillation cracked gas oil has a distillation point of 200 ° C. and 95% by weight has a distillation point of 360 ° C.
The cracked oil obtained above was distilled so that Tables 3 and 4 show the results and the like.

Example 2 Hydrolysis was performed in the same manner as in Example 1 except for the reaction temperature to obtain a cracked oil. The reaction temperature is 405 ° C. for the hydrodemetalization catalyst layer and 405 ° C. for the hydrocracking catalyst layer.
And the temperature of the hydrodesulfurization catalyst layer was 395 ° C. At this time, the desulfurization rate was 94% by weight, and the decomposition rate of the fraction at 343 ° C. or higher was 49% by weight.

In order to obtain the cracked gas oil by distilling the cracked oil obtained above, the target sulfur concentration of the cracked gas oil is set to 300 wt.
m and the target cetane index were set to 50. In this case, it is calculated that the distillation point of the cracked gas oil produced from the above formulas (1) and (2) needs to be 5% by weight ≧ 189 ° C. and 95% by weight ≦ 364 ° C. Therefore, 5% by weight of the distillation cracked gas oil has a distillation point of 200 ° C. and 95% by weight has a distillation point of 360 ° C.
The cracked oil obtained above was distilled so that Tables 3 and 4 show the results and the like.

Example 3 Hydrocracking was performed in the same manner as in Example 1 to obtain a cracked oil. In order to obtain the cracked gas oil by distilling the cracked oil obtained above, the target sulfur concentration of the cracked gas oil is set to 2
00 ppm by weight and a target cetane index of 50. In this case, the 5% by weight distillation point of the cracked gas oil produced from the above formulas (1) and (2) ≧ 197 ° C., the 95% by weight distillation point ≦ 34.
It is calculated that 7 ° C. is necessary. Then, the cracked oil obtained above was distilled so that the distillation cracked gas oil had a 5% by weight distillation point of 200 ° C. and a 95% by weight distillation point of 345 ° C.
Tables 3 and 4 show the results and the like.

Example 4 A hydrotreated feedstock was used as Arabian Heavy Atmospheric Residue B, and hydrogenated in the same manner as in Example 1 except for the reaction temperature to obtain a cracked oil. The reaction temperature is 395 ° C. for the hydrodemetalization catalyst layer and 400 ° C. for the hydrocracking catalyst layer.
And the temperature of the hydrodesulfurization catalyst layer was 395 ° C. At this time, the desulfurization rate was 88% by weight, and the decomposition rate of the fraction at 343 ° C. or higher was 35% by weight.

In order to obtain a cracked gas oil by distilling the cracked oil obtained above, the target sulfur concentration of the cracked gas oil is set to 500 wt.
m and the target cetane index were set to 50. In this case, it is calculated that it is necessary to set the 5% by weight distillation point ≧ 213 ° C. and the 95% by weight distillation point ≦ 356 ° C. of the cracked gas oil produced from the formulas (1) and (2). Therefore, 5% by weight of the distillation cracked gas oil has a distillation point of 220 ° C. and 95% by weight has a distillation point of 350 ° C.
The cracked oil obtained above was distilled so that Tables 3 and 4 show the results and the like.

Comparative Example 1 Hydrogenation treatment was performed in the same manner as in Example 1 to obtain a cracked oil. In order to obtain the cracked gas oil by distilling the cracked oil obtained above, the target sulfur concentration of the cracked gas oil was set to 4
00 ppm by weight and a target cetane index of 50. In this case, the 5% by weight distillation point ≧ 197 ° C. and the 95% by weight distillation point ≦ 36 of the cracked gas oil produced from the above formulas (1) and (2).
It is calculated that 2 ° C. is necessary. However, the cracked oil obtained above was distilled so that the distillation cracked gas oil had a 5% by weight distillation point of 200 ° C and a 95% by weight distillation point of 380 ° C. Tables 3 and 4 show the results and the like.

Comparative Example 2 Hydrocracking was carried out in the same manner as in Example 1 except that the raw material oil for hydrotreating was Arabian heavy atmospheric residual oil B to obtain a cracked oil. At this time, the desulfurization rate was 93
% By weight, the decomposition rate of the fraction at 343 ° C. or higher was 41% by weight. In order to obtain a cracked gas oil by distilling the cracked oil obtained above, the target sulfur concentration of the cracked gas oil was 400 ppm by weight, and the target cetane index was 50. In this case, the distillation point of 5% by weight of the cracked gas oil produced from the above formulas (1) and (2) ≧
It is calculated that it is necessary to set 197 ° C. and 95% by weight distillation point ≦ 362 ° C. However, the cracked oil obtained above was distilled such that the distillation cracked gas oil had a 5% by weight distillation point of 170 ° C and a 95% by weight distillation point of 360 ° C. Tables 3 and 4 show the results and the like.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

[Table 4]

As can be seen from Table 4, in Examples 1 to 4, the actual 5% or 95% distillation point of the cracked gas oil satisfies the condition of the formula shown in the present invention. The actual value of the sulfur concentration is below the target value, and the actual value of the cetane index of the cracked gas oil is above the target value. On the other hand, in the case of Comparative Example 1, the actual 95% by weight distillation point of the cracked gas oil deviated from the condition of the formula shown in the present invention, and as a result, the actual value of the sulfur concentration of the cracked gas oil exceeded the target value. I have. In the case of Comparative Example 2, the actual 5% by weight distillation point of the cracked gas oil deviated from the condition of the formula shown in the present invention. As a result, the actual value of the cetane index of the cracked gas oil was lower than the target value.

[0033]

As described above, the cracked oil obtained by subjecting the normal pressure resid to a hydrotreating process including hydrocracking according to the present invention is distilled at a predetermined distillation temperature to obtain a target sulfur concentration. And a cracked gas oil having a cetane index. In addition, by performing the above distillation at an existing petroleum refining plant, a low-sulfur gas oil base material that can respond to future quality regulations can be obtained without constructing new refining equipment or remodeling large equipment. It can be manufactured efficiently without trial and error.

Claims (2)

[Claims] 1. A cracked gas oil is produced by distilling a normal pressure residual oil from a cracked oil obtained by hydrotreating including at least hydrocracking so as to satisfy the following formulas (1) and (2). Method. B ≧ 278.5Y / (0.194XX + 0.072YY−0.017A + 43.6) −65.7 (1) C ≦ 26.5X / (-12.0XX−8.0YY + 1.lA + 1264.0) ) +332.9 (2) where A (° C.): 5% by weight distillation point of raw material residual pressure XX (% by weight): Decomposition of 343 ° C. or higher fraction in raw material residual pressure residual oil YY (% by weight): Desulfurization rate of raw pressure residual oil B (° C.): Distillation point of 5% by weight of cracked gas oil C (° C.): Distillation point of 95% by weight of cracked gas oil X (weight ppm): of cracked gas oil Target sulfur concentration Y (dimensionless): Indicates the target cetane index of cracked gas oil. However, XX ≧ 35 240 ≧ B ≧ 160 370 ≧ C ≧ 280 C−B ≧ 60. 2. The method for producing a cracked gas oil according to claim 1, wherein the hydrotreating including hydrocracking includes hydrotreating of hydrodemetallation, hydrocracking, and hydrodesulfurization.