JPH10195454A - Fluid catalytic decomposition of oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid catalytic decomposition method of oil capable of suppressing hydrogen transfer reaction after decomposition reaction of heavy fuel oil and excessive decomposition of light olefin, etc., and capable of obtaining light olefin oil in high yield. SOLUTION: When decomposing oil by bringing the oil into contact with a catalyst by using a fluid catalytic reactor equipped with a lower counter-current type reaction zone area, a separation zone, a stripping zone, a catalyst regenerating zone and a distillation zone, (1) a contact time in the reaction zone is 0.1-3.0sec and outlet temperature in the reaction zone is 530-700 deg.C and catalyst/oil ratio is 10-50 and (2) 1-50wt.% (based on oil) residual oil content comprising a hydrocarbon obtained by distilling a mixture of a decomposition product obtained by catalytically decomposing in a reaction zone with unreacted product and having >=300 deg.C boiling point is introduced into the outlet part of the reaction zone, and temperature of mixture of the decomposition product with the unreacted material and the catalyst is lowered by 1-100 deg.C, compared with temperature before introducing the residual oil content to produce light olefin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid catalytic cracking method for oil, and more particularly, to a method for converting ethylene, propylene,
The present invention relates to a fluid catalytic cracking (FCC) method for obtaining light olefins such as butene and pentene in high yield.

[0002]

2. Description of the Related Art In general catalytic cracking, petroleum hydrocarbons are decomposed by contact with a catalyst to obtain gasoline as a main product, a small amount of LPG, cracked gas oil, and the like. The catalyst is circulated and reused by burning and removing coke by air.

However, recently, there has been a movement to utilize a fluid catalytic cracking unit not as a gasoline production unit but as a light olefin production unit as a petrochemical raw material. The use of such a fluid catalytic cracker is
There are particular economic benefits in refineries where petroleum refining and petrochemical plants are highly linked. On the other hand, due to growing interest in environmental issues, regulations on olefin and aromatic contents in automobile gasoline or oxygen-containing base materials (MTBE)
Etc.) Mandatory addition has begun to take effect. This is expected to increase the demand for alkylate and MTBE as high-octane gasoline base materials to replace FCC gasoline and catalytic reforming gasoline. Therefore, it is necessary to increase the production of propylene and butene, which are the raw materials for these substrates.

As a method for producing a light olefin by fluid catalytic cracking of heavy oil, for example, a method in which a reaction is carried out at a high temperature (US Pat. No. 4,980,053), a method in which the contact time between a catalyst and a feed oil is shortened (U.S. Pat. No. 4,419,2)
21, U.S. Pat. No. 3,074,878, and U.S. Pat.
No. 62652, European Patent Publication No. 315179A
No.) and the like.

However, a problem common to these methods is that the yield of light olefins is reduced due to over-decomposition or hydrogen transfer reaction after leaving the reaction zone.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to suppress the hydrogen transfer reaction after heavy oil cracking reaction and the overcracking of light olefins and the like to reduce light olefins such as ethylene, propylene, butene and pentene. An object of the present invention is to provide a fluid catalytic cracking method for oil which can be obtained in a high yield.

[0007]

Means for Solving the Problems In the fluid catalytic cracking method of oil at a high temperature, the present inventors have developed a hydrogen transfer reaction after cracking reaction of heavy oil, light olefins and the like while increasing the cracking rate of heavy components. Intensive research has been conducted with a view to suppressing over-decomposition and obtaining light olefins in high yield. As a result, the specific temperature, the catalyst / oil ratio, the reaction temperature, the reaction type, and the contact time are employed, and a certain amount of the residual oil obtained by distilling the mixture of the decomposition product and the unreacted product is supplied to the reaction zone outlet. It has been found that the above object can be achieved by recycling and introducing the present invention, and the present invention has been completed.

[0008] That is, the fluid catalytic cracking method of the oil of the present invention comprises the use of a fluid catalytic cracking reactor having a downflow type reaction zone, a separation zone, a stripping zone, a catalyst regeneration zone and a distillation zone. In decomposing by contact with a catalyst, 1) the contact time in the reaction zone is 0.1 to 3.0.
The reaction zone outlet temperature is 530 to 700 ° C., the catalyst / oil ratio is 10 to 50, and 2) a mixture of a decomposition product and an unreacted product obtained by catalytic cracking in the reaction zone is obtained by distillation. Boiling point 300 ° C
The residual oil composed of the above hydrocarbons is
By introducing an amount of 0% by weight into the outlet of the reaction zone, the temperature of the mixture of decomposition products, unreacted materials and catalyst is reduced by 1 to 100 ° C. as compared with before the introduction of the residual oil, so that light olefins can be obtained. Is manufactured.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

[0010] The feedstock oil used in the present invention is mainly heavy oil. Examples of the heavy oil include a vacuum gas oil (VGO), an atmospheric residue, a vacuum residue, a pyrolysis gas oil, and a heavy oil obtained by hydrotreating these. Each of these heavy oils may be used alone, or a mixture of these heavy oils or a mixture of these heavy oils and a partly light oil can also be used.

The fluidized catalytic cracking reactor used in the present invention comprises a regeneration zone (regeneration tower), a downflow type reaction zone (reaction tower), a separation zone (separator), a stripping zone and a distillation zone. (Rectification tower).

The fluid catalytic cracking referred to in the present invention means that the above-mentioned heavy oil feedstock is brought into continuous contact with the catalyst maintained in a fluidized state under the above-mentioned specific operating conditions, and the heavy feedstock is mainly made of light olefin. Is to decompose into light hydrocarbons. In ordinary fluid catalytic cracking, so-called riser-cracking in which both the catalyst and the feed oil rise in the tube is employed.
In the present invention, since the catalyst / oil ratio is extremely large as compared with the ordinary fluid catalytic cracking method, it is also characterized by adopting a down flow cracking in which both the catalyst and the feed oil descend in the tube to avoid back mixing. One.

The heavy oil, which is the feedstock, is decomposed into light olefins in high yield by contact with a large amount of catalyst at a high temperature in the reaction zone. However, following the cracking reaction, light olefins extract hydrogen from paraffins, naphthenes, and aromatics, and are converted into light paraffins, which are undesirable products. In addition, a phenomenon called over-decomposition in which dry gas such as hydrogen gas, methane gas, ethane gas, and the like increases due to further decomposition generally occurs. In particular, when a high temperature and a high catalyst / oil ratio are employed as compared with the ordinary fluid catalytic cracking method as in the present invention, this phenomenon occurs remarkably. Therefore, it is important to stop the reaction immediately after the catalytic cracking reaction for a short time.

As a method for rapidly stopping the reaction, there is a method in which a quench oil or a quench gas is mixed with a mixture of the decomposition product, the unreacted product and the catalyst, and the mixture of the decomposition product, the unreacted product and the catalyst is quenched. Are known. Although the hydrogen transfer reaction and the over-decomposition reaction can be stopped to some extent by this method, the mixture of the decomposition products, unreacted products and the catalyst is required to stop the reaction sufficiently.
It is necessary to cool the reaction zone to 0 ° C. or lower, and when the outlet temperature of the reaction zone is as high as 530 to 700 ° C. as in the present invention, a large amount of quench oil or quench gas is required, which is not economically preferable. Also, by excessively cooling the mixture of decomposition products, unreacted materials and catalyst, the amount of coke required to maintain the regeneration zone temperature above 650 ° C. required for combustion of coke becomes too large, Inconveniences such as difficulty in maintaining heat balance occur.

The quench gas may be steam or a gas at a temperature and pressure to be injected, such as a paraffinic hydrocarbon having 1 to 6 carbon atoms such as methane, ethane, propane, butane, pentane and hexane, and a mixture thereof. Substances that can be present are preferably used.

The oil used as the quench oil in the present invention has a boiling point of 300 ° C. obtained by distilling a mixture of a decomposition product obtained by catalytically cracking a raw oil and an unreacted product.
As described above, the residual oil component consisting of a hydrocarbon containing 60% by weight or more, preferably 70% by weight or more of an aromatic component is exemplified. The aromatic content is less than 60% by weight or the boiling point is 300
If the temperature is lower than ℃, it is not preferable because reactions such as over-decomposition and hydrogen transfer cannot be stopped sufficiently. Specifically, uncracked oils and the like are mentioned.

As a characteristic of the residual oil, the raw oil contains a hardly decomposable component which remains without being decomposed after being subjected to catalytic cracking under high temperature, high catalyst / oil ratio reaction conditions, and has an extremely high aromatic content. In that it is a highly contained hydrocarbon.

After removing the catalyst by introducing a mixture of decomposition products, unreacted products and catalyst taken out of the reaction zone into the separation zone, the mixture of decomposition products and unreacted products is
It is introduced into a rectification column and distillation is performed. The residual oil obtained by distillation is removed from the rectification column, and at least a part is introduced into the outlet of the reaction zone.

In the present invention, the amount of the residual oil introduced into the outlet of the reaction zone (immediately after the outlet) is 1 to 50% by weight, preferably 2 to 30% by weight, more preferably 3 to 3% by weight based on the feedstock oil. 20% by weight. If it is less than 1% by weight, the reaction does not stop sufficiently, which is not preferable. On the other hand, when the content exceeds 50% by weight, the temperature of the regeneration zone is lowered by excessively cooling the catalyst in the mixture of the decomposition product, the unreacted product and the catalyst, which is not preferable.

By supplying the residual oil to the outlet of the reaction zone, the temperature of the mixture of the decomposition product, the unreacted product and the catalyst is 1 to 100 ° C., preferably 1 to 50 ° C.
More preferably, the temperature is lowered by 1 to 30 ° C.

In the downflow type reaction zone, a mixture of cracked products, unreacted materials and catalyst obtained by catalytic cracking of the raw oil and the catalyst kept in a fluidized state is cooled by introducing the above residual oil. After that, it is sent to the separation band.

The catalyst separated from the mixture of the decomposition products, unreacted products and the catalyst in the separation zone is sent to the catalyst stripping zone, and most of the hydrocarbons such as decomposition products and unreacted products are separated from the catalyst. Removed. The catalyst to which carbonaceous and partially heavy hydrocarbons are attached is sent from the stripping zone to the catalyst regeneration zone. In the catalyst regeneration zone, oxidation treatment of the catalyst to which carbonaceous materials are attached is performed. Examples of the oxidation treatment include a treatment such as combustion.
The catalyst that has undergone this oxidation treatment is a regenerated catalyst, from which carbonaceous materials and hydrocarbons deposited on the catalyst have been almost removed. This regenerated catalyst is continuously circulated to the reaction zone.

As the separation band, a cyclone separation band, a high-speed separation band, or the like is used. In the present invention, the high-speed separation zone refers to a zone in which the separation efficiency is lower than that of the cyclone separation zone but the residence time of the gas is short and the residence time distribution is short. Examples of the high-speed separation band include a box type and a U-vent type. Decomposition products removed from the separation zone and unreacted products are sent to a distillation zone.

In the present invention, a riser type regeneration zone, which is a riser of a lean moving bed, can be used as a regeneration zone in addition to a thick fluidized bed type regeneration zone used in a usual fluid catalytic cracking reactor. Further, a plurality of thick fluidized bed type regenerators and a riser type regenerator can be combined in series and used.

The reaction zone outlet temperature in the present invention refers to the outlet temperature of a down-flow type fluidized bed reactor.
This is the temperature before the decomposition products are quenched or separated from the catalyst. In the present invention, the reaction zone outlet temperature is 530-70.
It is 0 degreeC, Preferably it is 540-650 degreeC, More preferably, it is 550-620 degreeC. If the temperature is lower than 530 ° C., a light olefin cannot be obtained in a high yield.
If the temperature is higher than 0 ° C., thermal decomposition is remarkable, and the amount of dry gas generated is not preferable.

The term "catalyst / oil ratio" as used in the present invention refers to the ratio between the amount of circulating catalyst (ton / h) and the feed rate of feed oil (ton / h). And preferably 15 to 30. In the present invention, since the catalytic cracking reaction is performed in a short contact time, if the catalyst / oil ratio is less than 10, the catalytic cracking reaction does not sufficiently occur, which is not preferable. When the catalyst / oil ratio is larger than 50, the circulation amount of the catalyst is large, and the temperature of the regeneration zone is lowered, so that carbonaceous combustion does not sufficiently occur, or the catalyst residence time required for catalyst regeneration is undesirably too long. .

The term "contact time in the reaction zone" as used in the present invention refers to the time from when the regenerated catalyst comes into contact with the raw material oil until the mixture of cracked products, unreacted materials and catalyst reaches the point of introduction of the residual oil at the outlet of the reaction zone. Or the time until it is quenched. In the present invention, the contact time is 0.1 to
3.0 seconds, preferably 0.1 to 2.0 seconds, more preferably 0.3 to 1.5 seconds, even more preferably 0.3 to 1.0 seconds
A range of seconds is selected. If the contact time is less than 0.1 second, the raw material leaves the reaction zone before the reaction proceeds sufficiently, which is not preferable. If the contact time exceeds 3.0 seconds, the rate of conversion of light olefins to light paraffin or the like due to a hydrogen transfer reaction or overcracking that follows the cracking reaction is not preferred.

In the present invention, the temperature of the catalyst rich phase in the regeneration zone (hereinafter, referred to as regeneration zone temperature) refers to the temperature of the portion of the catalyst regeneration zone immediately before the catalyst flowing in the rich state exits the regeneration zone. . In the present invention, the regeneration zone temperature is 650 to 800 ° C, preferably 680 to 740 ° C.
It is. At a temperature lower than 650 ° C., the combustion of the carbonaceous material deposited on the catalyst becomes slow, and the carbonaceous material is not sufficiently removed to maintain the catalytic activity, or the catalyst in the regeneration zone is required to sufficiently remove the carbonaceous material. It is necessary to make the residence time very long, and the reproduction band becomes too large, which is not economically preferable. On the other hand, if the temperature is higher than 800 ° C., the catalyst undergoes hydrothermal degradation, and the amount of heat that the catalyst brings from the regeneration zone to the reaction zone becomes too large, so that the temperature of the reaction zone cannot be maintained at a preferable temperature, which is economically undesirable.

The operating conditions of the fluid catalytic cracking reactor of the present invention are not particularly limited except for the above, but the reactor is preferably operated at a reaction pressure of 1 to 3 kg / cm ² G.

The catalyst used in the present invention is not particularly limited, but a catalyst generally used for a fluid catalytic cracking reaction of petroleum can be used. In particular, a catalyst containing a superstable Y-type zeolite as an active ingredient and a matrix as a supporting base thereof is preferably used. As the matrix, kaolin,
Examples include clays such as montmorillonite, halloysite, and bentonite; inorganic porous oxides such as alumina, silica, boria, chromia, magnesia, zirconia, titania, and silica-alumina; and mixtures thereof. The ultra-stable Y-type zeolite content in the catalyst is 2 to 60% by weight,
Preferably it is 15 to 45% by weight.

In addition to the ultra-stable Y-type zeolite, crystalline aluminosilicate or silicoaluminophosphate (SAP) having a smaller pore diameter than Y-type zeolite
A catalyst containing O) can also be preferably used. As such a zeolite or SAPO, ZSM-5,
SAPO-5, SAPO-11 and SAPO-34 can be exemplified. These zeolites or SAPO may be contained in the catalyst particles containing the ultra-stable Y-type zeolite, or may be contained in other particles.

The bulk density of the catalyst particles is 0.5 to 1.0 g /
ml, average particle size 50-90 μm, surface area 50-35
0 m ² / g and the pore volume are preferably in the range of 0.05 to 0.5 ml / g.

The catalyst used in the present invention can be produced by a usual method. For example, a diluted solution of water glass (S
iO ₂ concentration = 8 to 13%) was added dropwise, pH2.0~4.
A silica sol of 0 is obtained. Ultra-stable Y-type zeolite and kaolin were added to the total amount of the silica sol and kneaded.
Spray dry with hot air at 0 ° C. After washing the spray-dried product thus obtained with 50 ° C. and 0.2% ammonium sulfate,
Dried in an oven at 80-150 ° C, then 400-
Calcination at 700 ° C. gives a catalyst.

[0034]

Next, embodiments of the present invention will be described, but the present invention is not limited thereto.

Example 1 As a fluid catalytic cracking reactor, an FCC pilot device (Xytel) having an adiabatic down-flow type reaction zone was used.
(Manufactured by the company) was used to decompose the Middle Eastern desulfurized VGO.

21550 g of a diluted solution of water glass (SiO ₂ concentration = 11.6%) was dropped into 3370 g of 40% sulfuric acid to obtain a silica sol having a pH of 3.0. Ultra-stable Y-type zeolite (manufactured by Tosoh Corporation: HSZ)
(-370HUA) 3000 g and kaolin 4000 g were added, kneaded, and spray-dried with hot air at 250 ° C. The spray-dried product thus obtained was washed with 0.2% ammonium sulfate at 50 ° C., dried in an oven at 110 ° C., and calcined at 600 ° C. to obtain a catalyst. Ultrastable Y in this catalyst
The type zeolite content was 30% by weight. At this time, the bulk density of the catalyst particles was 0.7 g / ml, the average particle size was 71 μm, the surface area was 180 m ² / g, and the pore volume was 0.12 ml / g.

The thus obtained catalyst was pseudo-equilibrated by a 100% steaming treatment at 800 ° C. for 6 hours before being supplied to the above apparatus. At this time, the equipment scale was 2 kg of inventory (catalyst amount) and 1 kg / h of feed amount. The operating conditions were a catalyst / oil ratio of 20 and a reaction zone outlet temperature of 6
The temperature was set to 00 ° C. and the contact time was set to 0.5 seconds. Of the residual oil having a boiling point of 343 ° C. or higher (aromatic component: 83% by weight) obtained by distilling a mixture of a decomposition product and an unreacted product obtained by catalytic cracking in a reaction zone, 50 g / h (raw oil) 5% by weight)
Was recycled and introduced immediately after the outlet of the reaction zone. The remaining residue was removed as product oil. For this reason, the temperature of the mixture of the decomposition product, unreacted matter and catalyst particles after the introduction of the residual oil is 596 ° C. lower than the reaction zone outlet temperature by 4 ° C.
It became. Table 1 shows the decomposition product yield at this time.

Example 2 Catalytic cracking was carried out in the same manner as in Example 1 except that the contact time was changed to 1.5 seconds.

Comparative Example 1 The same experiment as in Example 1 was carried out except that the residual oil was not recycled. Table 1 shows the decomposition product yield at this time.

COMPARATIVE EXAMPLE 2 Decomposition was carried out in the same manner as in Example 1, using the same apparatus scale, catalyst and raw material oil as in Example 1, under the same reaction conditions as in Example 1. However, instead of recycling the residual oil, dry gas 100g
/ H (10% by weight based on the feed oil)
It was introduced immediately after the outlet of the reaction zone. For this reason, the temperature of the mixture of the decomposition product, the unreacted product, and the catalyst after the introduction of the residual oil was 592 ° C., which was 8 ° C. lower than the reaction zone outlet temperature. Table 1 shows the decomposition product yield at this time.

Comparative Example 3 The reaction was carried out under the same conditions as in Example 1 except for the recycling of the residual oil, except that the reaction tower was changed to the upflow type. After the introduction of the residual oil, the temperature of the mixture of the decomposition product, the unreacted product, and the catalyst particles was 596 ° C., which was 4 ° C. lower than the reaction zone outlet temperature. Table 1 shows the decomposition product yield at this time.

[0042]

[Table 1] In the above table, C ₁ indicates methane gas, C ₂ indicates ethane gas, and the conversion indicates the conversion from feedstock to cracked products.
LCO indicates light cycle oil, and HCO indicates heavy cycle oil.

From the above results, the case where the residual oil was not recycled (Comparative Example 1) or the case where the dry gas was recycled instead of the residual oil (Comparative Example 1) Example 2) It can be seen that the hydrogen transfer reaction and the over-decomposition reaction can be suppressed, and a high light olefin yield can be obtained, as compared with the case where the reaction tower is set up flow (Comparative Example 3).

By lowering the temperature of the above mixture by quenching with dry gas or the like, the hydrogen transfer reaction and the over-decomposition reaction can be suppressed, but in the present invention, the catalyst / oil ratio is increased in order to increase the decomposition rate and the light olefin yield. Since the amount of the quench gas is larger than that of the residual oil, the temperature does not decrease so much as compared with the ordinary catalytic cracking method, and the effect of stopping the reaction is smaller than that of the residual oil.

[0045]

As described above, in addition to the combination of the catalyst / oil ratio, the reaction zone outlet temperature and the contact time within the ranges set in the present invention, and the downflow type reaction zone,
By recycling a certain amount of residual oil obtained by distilling a part of the mixture of the cracked product, unreacted product and catalyst, and quenching the mixture, the hydrogen transfer reaction after the cracking reaction of heavy oil and In addition, light decomposition of light olefins and the like can be suppressed, and light olefins such as ethylene, propylene, butene and pentene can be obtained in high yield.

Continued on the front page (72) Inventor Shunichi Yamamoto 8 Chidori-cho, Naka-ku, Yokohama-shi, Kanagawa Japan Oil Research Laboratory

Claims (1)

[Claims] 1. An oil is brought into contact with a catalyst by using a fluidized catalytic cracking reactor having a down-flow type reaction zone, a separation zone, a stripping zone, a catalyst regeneration zone, and a distillation zone. The contact time in the reaction zone is 0.1 to 3.0.
The reaction zone outlet temperature is 530 to 700 ° C., the catalyst / oil ratio is 10 to 50, and 2) a mixture of a decomposition product and an unreacted product obtained by catalytic cracking in the reaction zone is obtained by distillation. Boiling point 300 ° C
The residual oil composed of the above hydrocarbons is
By introducing an amount of 0% by weight into the outlet of the reaction zone, the temperature of the mixture of decomposition products, unreacted materials and catalyst is reduced by 1 to 100 ° C. as compared with before the introduction of the residual oil, so that light olefins can be obtained. And a fluid catalytic cracking method for oil.