JP4766940B2 - Method for producing hydrocarbon oil - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for hydrotreating heavy oil containing sulfur, and more specifically, using a mixed oil of reduced pressure light oil and atmospheric residual oil as the heavy oil, and hydrotreating it efficiently and economically. The present invention relates to an excellent hydrotreating method, which relates to a method for producing a feedstock for fluid catalytic cracking process that is highly desulfurized by using a combination of plural kinds of catalysts having an average pore diameter within a specific range.

  It is well known that sulfur contained in fuel oil such as gasoline is discharged into the atmosphere as sulfur oxide (SOx) during the combustion process, causing acid rain. Therefore, reduction of the sulfur content in fuel oil is required from the viewpoint of environmental conservation on a global scale. In recent years, there has been a strong demand for reduction of nitrogen oxide (NOx), which is an environmental pollutant contained in gasoline automobile exhaust gas, and in order to achieve this, sulfur in gasoline that causes the activity of the NOx removal catalyst to deteriorate. It is necessary to significantly reduce the minutes.

  On the other hand, fluid catalytic cracking (FCC) equipment has been developed to meet the increasing demand for gasoline, and now plays a central role in gasoline production. In recent years, there has been a great interest in FCC equipment as a process for producing light hydrocarbon oils with high added value from heavy hydrocarbon oils, seeking higher economic efficiency. In addition to conventional vacuum gas oil fractions as FCC feedstocks. In addition, a raw material oil mixed with a residual oil such as a normal pressure residual oil fraction is also used.

  Usually, since the vacuum gas oil fraction used as the feedstock for FCC equipment contains a large amount of sulfur compounds, the sulfur concentration of the gasoline fraction produced when used as an untreated FCC feedstock is very high. It becomes. In addition, when a heavier atmospheric residual oil is mixed as a raw material oil, since a larger amount of sulfur compound is contained, the sulfur concentration in the produced gasoline is further increased. For this reason, when vacuum gas oil and atmospheric residue are used as feedstock for the FCC unit, hydroprocessing (hydrodesulfurization) is performed using separate heavy oil hydrotreating units (heavy oil indirect desulfurization unit and heavy oil direct desulfurization unit). Are used as FCC feedstocks after reducing the sulfur concentration. In recent years, there has been a demand for further lower sulfur concentration in gasoline, and therefore it has become more important to desulfurize vacuum gas oil and atmospheric residue at a greater depth than ever.

  So far, many reports have been made on the hydrotreating method of FCC feedstock. For example, in a method for hydrotreating FCC feedstock, a hydrotreating zone having a relatively high reaction temperature and a first step in which desulfurization and denitrogenation are performed, and a nucleus having at least a lower reaction temperature and an aromatic bicycle or more There has been proposed a hydrotreating method for obtaining a FCC feedstock by hydrotreating a vacuum gas oil or an atmospheric residue at a second step of hydrogenation (see Patent Document 1). However, this method does not have sufficient desulfurization activity, and its operation control is complicated and it is difficult to say that it is economical.

  In addition, in the conventional method, in order to increase the added value, the depressurized gas oil and the atmospheric residual oil are hydrodesulfurized using separate heavy oil hydrotreating apparatuses as described above, and then the resulting oil is used. Since they are mixed and used as FCC feedstock, at least two hydrotreaters are required, which not only reduces the economic efficiency of the process, but also includes the associated devices, making the operation complicated and productive. Is not efficient.

  Conventionally, as a method for performing hydrogenation treatment of two kinds of raw material oils in one process, a method of performing hydrogenation treatment by mixing vacuum gas oil and light gas oil has been proposed (see Patent Document 2). However, in this method, hydrogenation is not performed in one process by combining a vacuum gas oil and a normal pressure residual oil that is a heavy oil containing a metal such as nickel or vanadium. As a feedstock for the FCC process, a feedstock mixed with a hydrotreated oil of residual oil containing metal components such as atmospheric residue in addition to vacuum gas oil has been used. Efficient desulfurization of heavy oil such as is also desired.

  Further, as a method of adding a heavy oil to the residual oil and performing a hydrogenation treatment, desulfurization is performed by hydrotreating by blending a diluent having a residual oil as a main component and having a boiling point range of 204 ° C. to the residual oil. And a metal removal method have been proposed (Patent Document 3). However, the hydrotreating catalyst used in this method is a general hydrotreating catalyst composed of silica, alumina, and silica-alumina, and in recent years there has been a demand for reducing the sulfur content in gasoline. It is difficult to produce the required low sulfur gasoline by simply mixing different fuel oils and desulfurizing them. The product oil described in Patent Document 3 has a high sulfur content, nickel content, and vanadium content, and in order to obtain recent low-sulfur gasoline, a further optimum production method including a catalytic process is desired.

JP-A-8-183964 JP-A-6-192663 Japanese Patent Laid-Open No. 4-290994

  In view of the above-described conventional situation, the present invention combines at least two kinds of heavy oils containing sulfur, such as vacuum gas oil and atmospheric residual oil, with a plurality of types of catalysts having an average pore diameter in a specific range. Thus, an object of the present invention is to provide a method for producing a hydrocarbon oil that can efficiently obtain a hydrotreated oil that has been suitably desulfurized as an FCC feedstock.

  As a result of earnest research to develop a method for efficiently producing a feedstock for FCC that has been highly desulfurized from heavy oil, the present inventors have conducted research on heavy oil containing a specific sulfur content under high temperature and pressure. In the method of hydrotreating in the presence of a catalyst, the raw heavy oil is a mixed oil of at least two heavy oils including a vacuum gas oil and an atmospheric residual oil, and the average pore diameter is in a specific range It was discovered that by using a combination of a plurality of types, it is possible to efficiently produce a hydrocarbon oil that becomes a feedstock for FCC, and the present invention has been proposed.

That is, the above-mentioned object of the present invention is a method for hydrotreating heavy oil having a sulfur content of 4.5% by mass or less in the presence of a catalyst under high temperature and pressure,
(1) The heavy oil contains 70% by mass or more of a mixed oil having a mixing ratio (mass ratio) of reduced pressure gas oil: normal pressure residual oil of 50:50 to 90:10 ,
(2) (a) and demetallization catalyst for removing metal values from heavy oil, of at least two (b), combines the desulfurization catalyst from heavy oil,
(3) (a) The average pore diameter of the demetallized catalyst is 15 to 25 nm, the pore volume is 0.6 to 0.8 ml / g, the catalyst strength is 9 N / mm or more by SCS,
(B) The heavy oil desulfurization catalyst has an average pore diameter of 6 to 15 nm, a specific surface area of 150 to 350 m ² / g, and a volume occupied by pores having an average pore diameter of ± 1.5 nm is at least 50 of the total pore volume. % Or more,
(4) reaction temperature 300 to 500 ° C., a hydrogen partial pressure of 3 to 20 mPa, hydrogen / oil ratio is 400~3000m ³ / ^{m 3,} hydrogenated liquid hourly space velocity is the condition of 0.1～3.0H ^-1 It has been achieved by a process for producing hydrocarbon oils to be treated.

  According to the present invention, by using a mixed oil of at least two types of heavy oils including a vacuum gas oil and a normal pressure residual oil as a raw material, and using a combination of a plurality of types of catalysts having an average pore diameter in a specific range, Can be deeply desulfurized. Accordingly, it is possible to efficiently provide a feedstock for FCC that is deeply desulfurized without requiring separate hydrotreating equipment for reduced pressure gas oil and atmospheric residual oil as in the past, and reduced in metal compounds such as nickel and vanadium. Can do. In the present invention, as specifically shown in Examples and Comparative Examples described later, by using a mixture of a vacuum gas oil and a normal pressure residual oil as a feedstock for hydrotreating, each feedstock oil is obtained by its synergistic effect. Compared to when hydrotreating each separately, the hydrodesulfurization reaction proceeds more effectively, and it is suitable as a feedstock for FCC by using an optimal catalyst in combination with this catalyst to enhance this effect. It becomes possible to efficiently produce the desulfurized hydrotreated oil.

  In the present invention, vacuum gas oil and atmospheric residual oil are used as at least two types of heavy oils containing sulfur, they are mixed, and the raw material oil containing the mixed oil is identified under an average pore size under high pressure. The present invention provides a method for producing a hydrocarbon oil that is highly hydrodesulfurized by using a combination of a plurality of types of catalysts in the above range and has reduced substances that poison the catalyst used in the FCC process.

  The sulfur content of the heavy oil used as the raw material oil in the present invention is preferably 4.5% by mass or less, and more preferably 3% by mass or less. When the sulfur content is 4.5% by mass or less, the sulfur content in the hydrotreated oil is suitably reduced, and the sulfur content in gasoline produced by FCC is also suitably reduced.

  There is no restriction | limiting in particular as a vacuum gas oil used as a raw material oil by this invention, It is a component fractionated by the vacuum distillation apparatus currently used as a raw material oil of the conventional heavy oil indirect desulfurization apparatus, The boiling point range is 320-550. A vacuum gas oil having a sulfur content of 1.0 to 3.5% by mass at ° C. can be suitably used.

  There is no particular limitation on the atmospheric residual oil used in the present invention, and it is a residue component fractionated by an atmospheric distillation apparatus used as a raw oil for a conventional heavy oil direct desulfurization apparatus, and has a boiling point range of 320 ° C. Thus, an atmospheric residual oil having a sulfur content of 2.0 to 4.5 mass% and nickel and vanadium contents of 10 to 150 ppm can be preferably used.

  Although at least two types of heavy oils are used as the raw material oil of the present invention, it is not particularly limited to only a mixed oil of reduced pressure light oil and atmospheric residual oil, and the fraction obtained by distillation from crude oil is heavy. It is also possible to use a raw material oil mixed with light oil, vacuum residue, or the like.

  In the present invention, at least two kinds of heavy oils containing sulfur are mixed and used as a raw material oil for hydroprocessing under high temperature and pressure in the presence of a catalyst. The mixing ratio of heavy oils at this time There is no restriction | limiting in particular, It is preferable to mix in the range of 5: 95-95: 5 by the ratio (mass) of vacuum gas oil and a normal-pressure residual oil, and 50: 50-90: 10 is more preferable. When mixing heavy gas oil, vacuum residue, etc., the sum of heavy gas oil and vacuum residue is usually from 0: 100 to 30:70 in the ratio (mass) of the sum of vacuum gas oil and atmospheric residue. Preferably, the sum of heavy gas oil and vacuum gas oil is more preferably 10:90 to 90:10, and more preferably 50:50 to 90:10, as the ratio (mass) to the sum of atmospheric residue and vacuum residue.

  Regarding the mixing method of the vacuum gas oil and the atmospheric residual oil in the present invention, it is only necessary to provide the hydrotreating apparatus in a sufficiently mixed state and the mixing method is not particularly limited. The same applies to the case of mixing heavy oil other than vacuum gas oil and atmospheric residue, and it can be suitably used regardless of the mixing method.

  In the present invention, as described above, heavy oil having a sulfur content of 4.5% by mass or less is hydrotreated under high temperature and pressure in the presence of a catalyst. A demetallation catalyst for removing water and a heavy oil desulfurization catalyst are used in combination.

  In order to effectively remove heavy metal oil containing heavy metals such as sulfur, asphaltene, nickel and vanadium, the demetallation catalyst is packed in the upstream part of the catalyst bed. As the refractory inorganic oxide carrier, alumina, silica, alumina-silica or the like may be used alone or as a mixture, and those obtained by mixing various metals such as boron oxide and zinc oxide may also be used. As the hydrogenation active component to be supported, a periodic table group 6 metal such as molybdenum or tungsten, or a periodic table group 8 metal such as cobalt or nickel can be used.

  In the metal removal catalyst, the average pore diameter is 15 to 25 nm, preferably 18 to 23 nm. When the average pore diameter is less than 15 nm, sufficient metal removal activity cannot be obtained, and when it exceeds 25 nm, the hydrotreating activity and the catalyst strength are lowered. The pore volume of the demetallation catalyst is 0.6 to 0.8 ml / g, preferably 0.65 to 0.8 ml / g. If the pore volume is in this range, the catalyst has sufficient catalyst life and catalyst strength, and stable operation is possible.

  The catalyst strength is 9 N / mm or more, preferably 13 N / mm or more in terms of SCS (Side Crushing Strength). The SCS is a value obtained by adding the excess weight with the catalyst placed horizontally, obtaining the load mass at which the catalyst is destroyed, and dividing by the catalyst length, indicating the breaking strength per unit length of the catalyst. If the SCS is 9 N / mm or more, catalyst cracks are less likely to occur in the reactor, and continuous operation is possible.

  A heavy oil desulfurization catalyst is filled downstream of the demetallation catalyst. As the refractory inorganic oxide carrier for the desulfurization catalyst, alumina, silica, titania, magnesia and the like are used alone or as a mixture. What mixed various zeolites, such as a zeolite, can also be used. As the hydrogenation active component to be supported, metals of Group 6 of the periodic table such as molybdenum and tungsten and metals of Group 8 of the periodic table such as cobalt and nickel can be used. Phosphorus, iron, platinum or the like can also be used.

In the heavy oil desulfurization catalyst, the average pore diameter is 6 to 15 nm, preferably 7 to 12 nm. If the average pore diameter is within this range, it has stable metal resistance and sufficient desulfurization performance can be obtained. The specific surface area of the desulfurization catalyst is 150 to 350 m ² / g, preferably 200 to 320 m ² / g. If the specific surface area is within this range, sufficient desulfurization performance can be obtained. The volume occupied by pores having an average pore diameter of ± 1.5 nm of the desulfurization catalyst needs to be at least 50% or more, preferably 60% or more of the total pore volume. If it is 50% or more, sufficient desulfurization activity can be exhibited.

  As the demetallation catalyst and desulfurization catalyst for heavy oil, it can be used regardless of the difference between the new catalyst and the regenerated catalyst. The ratio of heavy metal demetalization catalyst and desulfurization catalyst filling can be changed in a timely manner according to the operating conditions, and increasing the ratio of demetalization catalyst can prevent deterioration of activity due to metal. Thus, the desulfurization activity can be improved by increasing the ratio of the desulfurization catalyst.

  The production of the hydrocarbon oil of the present invention can be preferably carried out with a normal hydrodesulfurization apparatus and its operating conditions.

That is, the reaction conditions for the hydrotreating of the feedstock are as follows: the reaction temperature is 300 to 500 ° C., preferably 350 to 450 ° C., the hydrogen partial pressure is 3 to 20 MPa, preferably 5 to 17 MPa, more preferably 8 to 15 MPa, hydrogen / oil ratio 400~3000m ³ / m ^3, preferably 500~1800m ³ / m ^3, the liquid hourly space velocity 0.1~3.0h ^-1, preferably 0.2~2.0h ^-1, From these reaction conditions, the reaction conditions may be selected in a timely manner in consideration of the target amount of produced oil sulfur and catalyst activity.

If the reaction temperature is 300 ° C. or higher, the hydrotreating catalyst charged in the hydrotreating apparatus is fully active, and the effect of mixing at least two heavy oils containing sulfur as the feedstock is sufficient. If the temperature is 500 ° C. or less, the hydroprocessing apparatus can be operated smoothly without excessive thermal decomposition of the heavy oil, and the activity deterioration of the hydroprocessing catalyst can be suppressed.
When the hydrogen partial pressure is 3 MPa or more, the hydrogenation reaction proceeds sufficiently, and the effect of mixing two types of heavy oils as the raw material oil is sufficiently exhibited. If it is 20 MPa or less, it is possible to avoid an increase in equipment construction cost and operation cost, which is economical.
When the hydrogen / oil ratio is 400 m ³ / m ³ or more, the hydrogenation activity of the hydrotreating catalyst is exhibited, and the effect of mixing two types of heavy oils as the raw material oil is sufficiently exhibited. If the 3000 m ³ / m ³ or less, it is possible to prevent a significant reduction in economic efficiency.
If the liquid hourly space velocity is 0.1 h ^-1 or more, it can be secured economics, if 3.0 h ^-1 or less, two types of effects mixed with heavy oil as the feedstock is sufficiently exhibited.

  The sulfur content in the hydrotreated oil obtained by the present invention is preferably 0.15% by mass or less, more preferably 0.10% by mass or less, and further preferably 0.05% by mass or less. If the sulfur content is less than 0.15% by mass, the effect of mixing two kinds of heavy oils is sufficiently exhibited.

  Further, the content of nickel and vanadium in the hydrotreated oil is preferably 10 ppm or less, and more preferably 1 ppm or less. If it is 10 ppm or more, it becomes a poison for the catalyst used in the FCC process, and the activity of the catalyst is lowered.

  Further, the latent sludge in the hydrotreated oil is preferably 0.3% by mass or less, the actual sludge is preferably 0.2% by mass or less, the latent sludge is 0.2% by mass or less, and the actual sludge is 0.08% by mass or less. More preferred. If the latent sludge is 0.3% by mass or less and the actual sludge is 0.2% by mass or less, stable operation can be continued.

  By the above method, by using a mixed oil of at least a vacuum gas oil and a normal pressure residual oil as a raw material oil and hydrotreating under high temperature and pressure in the presence of a catalyst, these heavy oils are efficiently obtained. A low-sulfur feedstock for FCC desulfurized by an economical method can be stably produced. Thereby, a high quality gasoline fraction having an extremely low sulfur concentration can be obtained from the FCC process.

  Next, although an example and a comparative example explain the present invention, the present invention is not limited by these examples.

Example 1
As raw material oil, 65% by mass of vacuum gas oil (sulfur content concentration: 2.40% by mass) shown in Table 1 and 35% by mass of atmospheric residue (sulfur content concentration: 3.20% by mass) are mixed (of mixed oil). Sulfur content: 2.70% by mass), hydrogenation under conditions of reaction temperature = 398 ° C., hydrogen partial pressure = 13.2 MPa, hydrogen / oil ratio = 674 Nm ³ / kl, LHSV = 0.142 h ⁻¹ Processing was carried out. At that time, as a demetallation catalyst for removing metal from heavy oil, a catalyst (average pores) supported on alumina support from the reactor inlet at a ratio of 9% by mass of molybdenum as molybdenum oxide and 2% by mass of nickel as nickel oxide. 18 nm diameter, pore volume 0.7 ml / g, SCS 12 N / mm), catalyst supporting alumina as a desulfurization catalyst, 12% by mass of molybdenum as molybdenum oxide and 4% by mass of nickel as nickel oxide ( The average pore diameter is 8.5 nm, the specific surface area is 273 m ² / g, and the volume occupied by pores with an average pore diameter of ± 1.5 nm is 81% of the total pore volume). 15% by mass, catalyst supported at a rate of 3% by mass with nickel as nickel oxide (average pore diameter 10 nm, specific surface area 198 ² / g, the volume occupied by the pores having an average pore diameter ± 1.5 nm is used in combination three types of catalytic 78%) of the total pore volume in this order.
The obtained product oil was subjected to fractional distillation treatment, and the obtained FCC feedstock oil fraction (boiling point: 353 ° C. or higher) was analyzed for sulfur content, nickel and vanadium content, latent sludge amount, and actual sludge amount. The results are shown in Table 2.

Example 2
65% by mass of vacuum gas oil (sulfur content concentration: 2.40% by mass) shown in Table 1 and 35% by mass of normal pressure residual oil (sulfur content concentration: 3.16% by mass) (sulfur content of mixed oil: 2.67% by mass), raw material oil, reaction processing temperature = 362 ° C., LHSV = 0.130 h ⁻¹ , molybdenum removal catalyst from the reactor inlet as a demetallation catalyst for removing metal from heavy oil, molybdenum support Catalyst having an average pore diameter of 21 nm, pore volume of 0.71 ml / g, SCS16 N / mm, and an alumina support as a desulfurization catalyst. to 15% by weight and 3% by weight percentage in supported catalyst (average pore diameter 10.5nm nickel as nickel oxide of molybdenum as molybdenum oxide, a specific surface area of 182m ² / g, Rights The volume occupied by pores with a pore diameter of ± 1.5 nm is 72% of the total pore volume), and the alumina carrier carries molybdenum at a rate of 12% by mass as molybdenum oxide and nickel at 4% by mass as nickel oxide. Three types of catalysts (in this order, the average pore diameter is 8.5 nm, the specific surface area is 273 m ² / g, the average pore diameter is ± 1.5 nm and the volume occupied by the pores is 80% of the total pore volume). The procedure was the same as in Example 1 except that these were used in combination. Table 2 shows the analysis results of the sulfur content, nickel and vanadium contents, latent sludge content, and actual sludge content in the FCC feedstock fraction of the resulting product oil.

Example 3
50% by mass of vacuum gas oil (sulfur concentration: 2.75% by mass) and 50% by mass of residual atmospheric pressure (sulfur concentration: 2.92% by mass) shown in Table 1 are used as raw material oil for reaction treatment Example 1 was repeated except that the temperature was 390 ° C., the hydrogen partial pressure was 11.5 MPa, the hydrogen / oil ratio was 972 Nm ³ / kl, and LHSV was 0.25 h ⁻¹ . Table 2 shows the analysis results of the sulfur content, nickel and vanadium contents, latent sludge content, and actual sludge content in the FCC feedstock fraction of the resulting product oil.

Comparative Example 1
The vacuum gas oil and atmospheric residue used as the feedstock of Example 1 were separately hydrotreated under the conditions of Example 1, and the FCC feedstock fraction of the product oil was obtained from the vacuum gas oil obtained, and the atmospheric residue. After the FCC feedstock fraction of the product oil obtained from the oil was mixed at a ratio of 65% by mass and 35% by mass, sulfur content analysis was performed. The results are shown in Table 3.

Comparative Example 2
The vacuum gas oil and the atmospheric residue used as the feedstock of Example 2 were separately hydrogenated under the conditions of Example 2, and the FCC feedstock fraction of the product oil obtained from the vacuum gas oil and the atmospheric residue After the FCC feedstock fraction of the product oil obtained from the oil was mixed at a ratio of 65% by mass and 35% by mass, sulfur content analysis was performed. The results are shown in Table 3.

Comparative Example 3
The vacuum gas oil and the atmospheric residue used as the feedstock of Example 3 were separately hydrotreated under the conditions of Example 3, respectively, and the FCC feedstock fraction of the product oil obtained from the vacuum gas oil and the atmospheric residue After mixing the FCC feedstock fraction of the product oil obtained from the oil at a ratio of 50 mass% and 50 mass%, sulfur content analysis was performed. The results are shown in Table 3.

Comparing the above examples and comparative examples, as is clear from Tables 2 and 3, in any case, the sulfur concentration in the FCC feedstock fraction of the product oil in the examples is lower than in the comparative examples. confirmed. This is because, by using a mixture of vacuum gas oil and atmospheric residual oil as feedstock for hydrotreating, the synergistic effect makes it more effective than when hydrotreating each feedstock individually. It was shown that hydrodesulfurization reaction proceeds.
Moreover, also about nickel and vanadium content, the Example has shown the low value compared with the comparative example, and this is using each vacuum feed oil and a normal-pressure residual oil by mixing and using each raw material by the synergistic effect. It has been shown that the demetallation reaction proceeds more than when the oils are treated individually.

Claims (1)

In a method of hydrotreating heavy oil having a sulfur content of 4.5% by mass or less under high temperature and pressure in the presence of a catalyst,
(1) The heavy oil contains 70% by mass or more of a mixed oil having a mixing ratio (mass ratio) of reduced pressure gas oil: normal pressure residual oil of 50:50 to 90:10 ,
(2) (a) and demetallization catalyst for removing metal values from heavy oil, of at least two (b), combines the desulfurization catalyst from heavy oil,
(3) (a) The average pore diameter of the demetallized catalyst is 15 to 25 nm, the pore volume is 0.6 to 0.8 ml / g, the catalyst strength is 9 N / mm or more by SCS,
(B) The heavy oil desulfurization catalyst has an average pore diameter of 6 to 15 nm, a specific surface area of 150 to 350 m ² / g, and a volume occupied by pores having an average pore diameter of ± 1.5 nm is at least 50 of the total pore volume. % Or more,
(4) reaction temperature 300 to 500 ° C., a hydrogen partial pressure of 3 to 20 mPa, hydrogen / oil ratio is 400~3000m ³ / ^{m 3,} hydrogenated liquid hourly space velocity is the condition of 0.1～3.0H ^-1 A method for producing a hydrocarbon oil to be treated.