JPH08134471A - Method of inhibiting dry sludge generation in hydrogenation of heavy oil - Google Patents

Abstract

PURPOSE: To provide a method of inhibiting the generation of a dry sludge in the hydrogenation of a heavy oil. CONSTITUTION: A heavy oil comprising a topping residue or a vacuum distillation residue or a mixture of both is hydrogenated using a pretreatment catalyst preferably having an average pore diameter of 100-250Å, while regulating the product oil so as to have an asphaltene to resin weight ratio of 1 or lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing the production of dry sludge in the hydrotreatment of heavy oil.

[0002]

2. Description of the Related Art When heavy oil such as atmospheric distillation residue or reduced pressure distillation residue oil is hydrotreated, if deep desulfurization or high temperature operation is performed, it is continuously performed for one year. In that case, the production of dry sludge in the produced oil becomes remarkable in the latter half of the operation period. This dry sludge is
The heat exchanger and line filter of the equipment may be clogged, or the catalyst bed may be blocked, which hinders the equipment operation. Moreover, if it is mixed in the product, the quality of the product heavy oil will be deteriorated. Therefore, in such hydrotreating, how to suppress the generation of dry sludge is very important.

Generally, dry sludge refers to an insoluble substance in oil and includes metal powder, sand, coke, etc., but the dry sludge produced when hydroprocessing heavy oil is asphaltene content. The main component is a coke-like substance that has not been dispersed in oil due to polymerization.

The amount of dry sludge in heavy oil can be easily measured by a spot test (Japan Petroleum Institute method), and the amount of dry sludge is represented by a spot value (1 to 5). Usually, when the spot value is 3 or more, it is said that combustion when heavy oil is used as fuel and operation of the heavy oil treatment device will be hindered.

In the spot test, one drop of a sample heated to 60 ° C. and uniformly stirred is appropriately placed on a filter paper and left in a dryer at 100 ° C. for 1 hour to obtain a dark brown or black brown pattern beforehand. It is judged by visual comparison with the patterns (5 types) of the standard spots of the Japan Petroleum Institute that have been created and by the value of the closest standard spot (an integer of 1 to 5). Therefore, although the spot test can be performed in a relatively short time, it is inevitable that the value varies depending on the measurer (judgment person). Therefore, the conventional estimation of the dry sludge generation time by the spot test has a drawback of lacking reliability.

Several methods have been proposed in the past as a method for avoiding the formation of dry sludge. For example, if it is confirmed that dry sludge is produced in the produced oil, the operating conditions are relaxed and the reaction temperature is lowered, or other changes are made. However, such an avoidance method not only restricts the operation plan and reduces the quality of the product, but also
There will be problems such as extra costs for arranging and switching light materials.

Another method is to add an additive to the produced oil to disperse the dry sludge well in the produced oil, but this leaves a problem in the cost of the additive and dispersion stability. ing.

The present invention solves these problems, hydrotreating heavy oils without any restrictions and without degrading the quality of the product and without incurring any additional costs. An object of the present invention is to provide a method for suppressing the generation of dry sludge in the above.

[0009]

In order to achieve the above object, the inventors of the present invention analyzed or reacted a hydrotreated product oil of a heavy oil consisting of an atmospheric distillation residue or a vacuum distillation residual oil or a mixed oil thereof. As a result of conducting an analysis of the mechanism and conducting a diligent research on the generation mechanism of dry sludge, by maintaining the ratio of the weight of asphaltene in the hydrotreated product oil to the weight of resin to 1 or less, the dry sludge of They have found that generation can be avoided, and have completed the present invention.

That is, the present invention uses a pretreatment catalyst in hydrotreating a heavy oil and keeps the ratio of the weight of asphaltene in the produced oil to the weight of the resin to be 1 or less. The gist is the method of controlling dry sludge in the hydrotreatment of. Further, in the present invention,
It is preferable to use a pretreatment catalyst having an average pore size in the range of 100 to 250Å.

When hydrotreating an atmospheric or vacuum distillation residual oil, a reaction system comprising a pretreatment reactor and a plurality of hydrodesulfurization reactors is often used. In this reaction system, generally, a demetallization reactor is used as a pretreatment reactor, and in the demetalization reactor, vanadium, nickel, etc. in a feed oil which becomes a catalyst poison of a desulfurization catalyst in a subsequent hydrodesulfurization reactor are The metal is pre-removed and then the feedstock is hydrodesulfurized to the desired desulfurization level in a hydrodesulfurization reactor.

The asphaltene component and the resin component, which are heavy components, are present in the residual oil of atmospheric pressure or reduced pressure in an amount of 2 to 10% by weight and 6 to 20% by weight, respectively, and these are decomposed in the hydrogenation reaction process. The content thereof changes due to polymerization or polymerization. The heavy oil, which is the feedstock in the present invention, is atmospheric distillation residue or reduced pressure distillation residual oil, and these may be used alone or as a mixture of both.

Generally, heavy oil can be divided into four components, a saturated component, an aromatic component, a resin component, and an asphaltene component by solvent fractionation. At this time, depending on the type of the solvent used, the measured values thereof may slightly vary due to the difference in solubility. In the present invention, the values obtained by thin layer chromatography are the resin content and the asphaltene content, respectively. That is, 1 microliter of a sample (hereinafter referred to as μL) was dropped on a thin-layer silica rod, and the silica rod was suspended in a developing solvent tank containing an n-hexane solvent for a predetermined time to dissolve n-hexane. Minute (saturated) and n-hexane insoluble matter are separated. Then, this silica rod is suspended in a developing solvent tank containing toluene for a predetermined time, and n-
Hexane insoluble matter is developed and separated into toluene soluble matter (aromatic matter) and toluene insoluble matter. Further, this silica rod is suspended in a developing solvent tank containing THF (tetrahydrofuran) for a predetermined time, and a toluene insoluble matter is developed and separated into a THF soluble matter (resin content) and a THF insoluble matter (asphaltene content). When each component thus developed on the thin-layer silica rod is quantified using a thin-layer chromatograph (TLC-FID) equipped with a hydrogen flame ionization detector, the resin and asphaltene components are contained. Each quantity is required.

The cause of the production of dry sludge from the hydrotreated product oil has not been clarified, but at least the content of asphaltene or resin in the raw material or product oil has an effect. By appropriately controlling, the generation of dry sludge can be suppressed.

A method for maintaining the ratio of the weight of asphaltene to the weight of resin (hereinafter, abbreviated as A / R ratio) to 1 or less is to hydrotreat heavy oil such as atmospheric distillation residue or vacuum distillation residual oil. To exert a high degree of asphaltene reforming function of a pretreatment catalyst used in an existing pretreatment metallization reactor usually used for, or in a pretreatment reactor newly installed to carry out the present invention. Achieved by

The above-mentioned new pretreatment reactor may have the same design as the existing pre-demetallization reactor, or may have a different design (for example, the reactor size or the catalyst bed type is changed).
It can also be. Further, the pretreatment catalyst used in this newly installed pretreatment reactor is substantially the same as the pretreatment catalyst used in the existing predemetallization reactor, as described later. In the present invention, the above existing pre-demetallization reactor,
Either of the newly installed pretreatment reactors may be used alone, or the existing prestage demetallization reactor and the newly installed pretreatment reactor may be used together.

In order to exert the asphaltene reforming function of the pretreatment catalyst to a high degree, the pretreatment catalyst is used during the period when the reforming function is effectively working, and a new catalyst is exchanged immediately before the function disappears. Or a method of continuously extracting a part of these catalysts during the pretreatment operation and continuously supplying a new catalyst according to the amount of extraction.

The catalyst bed of the existing pre-stage demetallization reactor or the new pretreatment reactor may be of any type of fixed bed, swing reactor, fluidized bed, slurry bed, boiling bed or moving bed.

From the viewpoint of reducing the amount of new investment, the pretreatment catalyst exchange method makes effective use of existing equipment, and the existing pre-stage demetallization reaction tower (fixed bed reactor) and new pretreatment reaction tower (fixed bed reaction) are used. Each of the reactors) is filled with a pretreatment catalyst that has the same asphaltene reforming function, and by adopting a swing reactor type, there is a method of constantly passing oil through one of the reaction towers to maintain a high asphaltene reforming function. preferable.

That is, the oil produced in the hydrotreating apparatus is periodically sampled and analyzed, and when the A / R ratio reaches 0.90, preferably 0.95, the pretreatment in which the asphaltene reforming function is lowered. It is desirable to switch from the catalyst to a new pretreatment catalyst with a high asphaltene reforming function. The pretreatment catalyst having a reduced asphaltene reforming function can be reused after a predetermined regeneration treatment.

As the pretreatment catalyst, there can be used IIIb of the periodic table.
A catalyst in which an oxide of Group IVb or Group IVb is used as a carrier and a metal of Group VIa or Group VIII of the periodic table is supported is used. In particular, alumina is used as a carrier, nickel and / or molybdenum is supported, and the average pore diameter is 100.
It is preferable to use one having a range of 250 to Å, more preferably 150 to 200 Å.

If the average pore size is less than 100Å, asphaltene cannot be taken in sufficiently, so that the asphaltene is not modified and the A / R ratio becomes larger than 1, resulting in the formation of dry sludge. Average pore size is 250
If it is larger than Å, the surface area will be significantly reduced, and the efficiency of the asphaltene reforming function will be reduced as a whole.
The / R ratio increases and dry sludge is generated.

The reaction conditions of the existing pre-demetalization catalyst bed or the newly installed pretreatment catalyst bed may be the same as or different from the reaction conditions of the subsequent hydrodesulfurization unit. The reaction conditions for at least the existing pre-demetalization catalyst bed or the newly installed pretreatment catalyst bed are that the temperature is 300 to 450 ° C,
Preferably 350-420 ° C., hydrogen partial pressure 50-200
kg / cm ² , preferably 100 to 170 kg / c
m ² , the liquid hourly space velocity is 0.05 to 2.0 Hr ⁻¹ , preferably 0.1 to 1.0 Hr ⁻¹ , the ratio of hydrogen to the feed oil (H
₂ / oil) is 150 to 1700 Nm ³ / m ³ , preferably 450 to 1400 Nm ³ / m ³ .

The hydrodesulfurization catalyst is not particularly limited as long as it can achieve a desired desulfurization level.
Generally, an oxide of Group IIIb or IVb of the periodic table is used as a carrier, and Group VIa or V of the periodic table is used as a carrier.
A catalyst supporting a Group III metal is used. As such a catalyst, it is preferable to use one having at least one of nickel, cobalt, and molybdenum supported on an alumina carrier and having an average pore diameter of 30 to 140Å, more preferably 50 to 100Å. desirable. The conditions for the hydrodesulfurization reaction are a temperature of 300 to 450 ° C., preferably 3
50 ~ 420 ℃, hydrogen partial pressure 50 ~ 200kg / c
m ² , preferably 100 to 170 kg / cm ² , liquid hourly space velocity of 0.05 to 2.0 Hr ⁻¹ , preferably 0.1.
1.0Hr ^-1 , ratio of hydrogen to feedstock (H ₂ / oil)
Is 150 to 1700 Nm ³ / m ³ , preferably 450 to
It is desirable to set it to 1400 Nm ³ / m ³ .

[0025]

【Example】

Example 1 Using the atmospheric distillation residual oil shown in Table 1 as a feed oil, and using the catalyst 1 shown in Table 2 as a catalyst, pretreatment was performed in an existing predemetallization reactor, and then the reformed oil was The hydrogenation treatment was performed using the catalyst 4 shown in FIG. The reaction conditions of the pretreatment are as follows: hydrogen partial pressure 145 kg / cm ² , liquid space velocity 0.69 Hr ⁻¹ ,
The ratio of hydrogen to treated oil was 680 Nm ³ / m ^3, and the reaction conditions of the hydrotreatment were: hydrogen partial pressure 145 kg / cm ² , liquid hourly space velocity 0.37 Hr ^-1 , ratio of hydrogen to treated oil 680 Nm.
³ / m ³ . Further, the reaction temperatures of the pretreatment and the hydrotreatment were changed so that the sulfur content of the produced oil of the hydrotreatment was 0.3% by weight. Table 3 shows the results of the pretreatment and the hydrogenation treatment as described above.

As is clear from Table 3, since the pretreatment catalyst was used for 170 days and the A / R ratio was close to 1, only the pretreatment catalyst was replaced with a new one, and the reaction was conducted under the same conditions as above. Continued. The number of days to use the pretreated catalyst after replacement is 20
At 130 days, the A / R ratio of the produced oil was 1 or less,
No formation of dry sludge was observed.

Comparative Example 1 In Example 1, a reaction experiment was conducted for 300 days without replacing the pretreatment catalyst. The results are shown in Table 4. As is clear from Table 4, when the number of days of use of the pretreatment catalyst exceeded 170 days, the A / R ratio of the produced oil was 1 or more, and the production of dry sludge became remarkable.

Comparative Example 2 Catalyst 4 shown in Table 2 was charged as the pretreatment catalyst in Example 1, and the reaction was carried out for 20 days under the same conditions as in Example 1.
The results are shown in Table 5. As is clear from Table 5, when the pretreatment catalyst was used for 20 days, the A /
The R ratio was 1 or more, and the generation of dry sludge became remarkable.

Example 2 Catalyst 2 shown in Table 2 was charged as the pretreatment catalyst in Example 1 and the reaction was carried out for 20 days under the same conditions as in Example 1.
The results are shown in Table 5. As is clear from Table 5, when the pretreatment catalyst was used for 20 days, the A /
The R ratio was 1 or less, and no dry sludge was generated.

Example 3 Catalyst 3 shown in Table 2 was filled as the pretreatment catalyst in Example 1 and the reaction was carried out under the same conditions as in Example 1. The results are shown in Table 5. As is clear from Table 5, when the pretreatment catalyst was used for 20 days, the A / R ratio of the produced oil was 1
Below, no dry sludge was produced.

Example 4 Catalyst 5 shown in Table 2 was filled as the pretreatment catalyst in Example 1 and the reaction was carried out under the same conditions as in Example 1. The results are shown in Table 5. As is clear from Table 5, when the pretreatment catalyst was used for 20 days, the A / R ratio of the produced oil was 1
Below, no dry sludge was produced.

Example 5 Catalyst 6 shown in Table 2 was filled as the pretreatment catalyst in Example 1 and the reaction was carried out under the same conditions as in Example 1. The results are shown in Table 5. As is clear from Table 5, when the pretreatment catalyst was used for 20 days, the A / R ratio of the produced oil was 1
Below, no dry sludge was produced.

Example 6 As a pretreatment catalyst in Example 1, the catalyst 7 shown in Table 2 was filled and the reaction was carried out under the same conditions as in Example 1. The results are shown in Table 5. As is clear from Table 5, when the pretreatment catalyst was used for 20 days, the A / R ratio of the produced oil was 1
Below, no dry sludge was produced.

Example 7 The catalyst 8 shown in Table 2 was charged as the pretreatment catalyst in Example 1 and the reaction was carried out under the same conditions as in Example 1. The results are shown in Table 5. As is clear from Table 5, when the pretreatment catalyst was used for 20 days, the A / R ratio of the produced oil was 1
Below, no dry sludge was produced.

Example 8 In Example 1, the feedstock oil was the vacuum distillation residual oil shown in Table 1, and the reaction conditions of the pretreatment were the same as in Example 1 except that the reaction temperature was 400 ° C. The reaction conditions for the hydrotreatment were the same as in Example 1 except that the reaction temperature was adjusted so that the sulfur content of the produced oil was 0.4% by weight. The results are shown in Table 6.

As is clear from Table 6, the A / R of the produced oil
As a result of exchanging the pretreatment catalyst with a new one in 100 days and 200 days of oil passage when the ratio was close to 1, it became possible to operate for a long period of time while maintaining the initial reaction conditions and produced oil quality without producing dry sludge. It was

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

[Table 4]

[0041]

[Table 5]

[0042]

[Table 6]

Example 9 The same procedure as in Example 8 was carried out except that the raw material oil was an equimolar mixture of the atmospheric distillation residual oil and the vacuum distillation residual oil shown in Table 1 and had the properties shown in Table 7. And hydrogenated. The results are shown in Table 8.

As is clear from Table 8, the A / R of the produced oil
As a result of replacing the pretreatment catalyst with a new one at 150 days and 300 days of oil passage when the ratio became close to 1, it became possible to operate for a long period of time while maintaining the initial reaction conditions and the quality of produced oil without producing dry sludge. It was

[0045]

[Table 7]

[0046]

[Table 8]

[0047]

As described above in detail, according to the present invention, not only the generation of dry sludge can be suppressed in the hydrotreatment of heavy oil such as atmospheric distillation residue or reduced pressure distillation residue oil, It is possible to perform stable long-term operation without changing the initial reaction conditions and the target product quality during operation. In particular, the present invention uses a relatively poor heavy oil having an asphaltene content of 4% by weight or more, which has a large tendency to generate dry sludge, as a raw material, and a target amount of sulfur in the produced oil is 0. The effect of suppressing the generation of dry sludge is great when, for example, a relatively strict treatment condition of 3% by weight or less is adopted.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yusuke Shibata 1134-2, Gongendo, Satte City, Saitama Prefecture, inside the Research and Development Center, Cosmo Research Institute (72) Yasuo Yamamoto, 1134, Gongendo, Satte City, Saitama Prefecture 2 Cosmo Research Institute R & D Center (72) Inventor Hatsutaro Yamazaki 1134-2 Gongendo, Satte City, Saitama Cosmo Research Institute R & D Center

Claims (2)

[Claims] 1. A hydrotreatment of a heavy oil, characterized in that a pretreatment catalyst is used in the hydrotreatment of the heavy oil, and the ratio of the weight of asphaltene in the produced oil to the weight of the resin is kept at 1 or less. Method of controlling dry sludge in processing. 2. The method for suppressing dry sludge in hydrotreatment of heavy oil according to claim 1, wherein a pretreatment catalyst having an average pore diameter of 100 to 250 Å is used.