JPH10251664A - Catalytic cracking process for hydrocarbon oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalytic cracking process for high-quality hydrocarbon oils which can be applied at a low cost and has such advantages that the structure is simple, that a gas for transporting solids in not necessary, and that the pressure balance for smoothly circulating solids is easily maintained. SOLUTION: In this method, a hydrocarbon oil (e.g. a heavy oil) is subjected to downflow contact with a fluidized catalytic cracking catalyst comprising silica, alumina, etc. The oil is subjected to catalytic cracking by using a circulating flucidized bed system comprising a vertical downflow moving bed reactor 12 to which the catalyst(Ct) is supplied, a dense-phase fludized bed stripping apparatus 13 which is connected to and installed below the rector 12 and in which the superficial velocity of an inert stripping gas is set at 0.03-0.7m/s, a dense-phase fluidized bed regeneration apparatus 14 into which the catalyst(Ct) is introduced from the stripping apparatus 13, and an upflow regeneration apparatus 15 comprising a medium- to high-speed lean-phase moving bed which is connected to the top of the regeneration apparatus 14 and circulates the catalyst(Ct) to the reactor 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for contacting hydrocarbon oils in which a hydrocarbon oil as a reaction gas is subjected to a cracking reaction in a down-flow reactor using a powdery solid as a fluid catalytic cracking solvent. It relates to a decomposition method.

[0002]

2. Description of the Related Art A reaction system in which a powdery solid is used as a catalyst or a heat medium and brought into contact with a reactant gas has been known for a long time, for example, used for catalytic cracking of hydrocarbon oil such as heavy oil. Have been. Some of such fluidized bed reactors use a thick fluidized bed (bubble fluidized bed), and others use a high-speed moving bed (high-speed fluidized bed). A reaction requiring a short contact time between a solid and a gas uses a high-speed moving bed. At present, in gasoline production apparatuses by fluid catalytic cracking of heavy oil and the like, an upflow type high-speed moving bed reactor called a riser is mainly used. This is because, in order to increase the selectivity of a preferable product such as gasoline, the catalytic performance has been improved and the contact time has been shortened to suppress undesired reactions such as over-decomposition.

[0003] However, in a riser type reactor, a problem of back mixing occurs. Backmixing is a phenomenon in which a portion of a gas or solid moves in the opposite direction to the original flow by gravity acting downward on a rising mixed flow.
When such backmixing of gas occurs, a portion of the gas is withdrawn from the reactor without contact time because the contact time is too short, and another portion of the gas is too long contact time, such as over-decomposition. Undesirable reactions occur, leading to degradation of product quality. In addition, when the back mixing of the solid occurs, a part of the solid stays in the reactor for a long time in a deteriorated state, and the efficiency of the reaction decreases.

In order to avoid this, a downflow type reactor has recently been used. For example, recently, Japanese Patent Application Laid-Open No. 4-261494, U.S. Pat. No. 5,462,652, U.S. Pat.
5,985, Japanese Patent No. 2523325 and the like introduce a system using a downflow type reactor. These proposals are intended to provide sufficiently short contact times and to prevent backmixing of solids and gases and to improve product selectivity. However, these techniques still have problems when viewed as a circulating fluidized bed system that continuously performs reaction and regeneration. These problems have been achieved in terms of how efficiently the solids can be returned to their original height, since the solids are dropped down in a down-flow reactor and then regenerated and subjected to the reaction again. It is due to not having.

For example, in the above-mentioned Japanese Patent Application Laid-Open No. Hei 4-261494, the regenerated catalyst is raised to the height of the reactor inlet by the transfer gas. Gas is required as a transfer medium for lift-up, so that the blower capacity becomes excessive and the structure of the apparatus becomes complicated, which is economically undesirable. U.S. Pat. No. 5,462,652 is similarly disadvantageous in that it requires a gas as a transfer medium to lift up the catalyst in addition to the air required to regenerate the catalyst.

Further, in US Pat. No. 4,385,985, there is a technique in which a catalyst is lifted up using combustion air by an upflow regenerator. However, this technique is actually difficult to use in the following points. That is, in order to lift up the catalyst, a pressure loss occurs at the expense of the work, and as a result, the pressure of the regeneration air inlet increases,
It is overlooked that the pressure needs to be suppressed by the static pressure of the dense layer of the catalyst formed in the stripping device. When the pressure of the regeneration air inlet becomes higher than the static pressure of the catalyst rich layer of the stripping device, the combustion air flows back to the stripping device side and the catalyst cannot be circulated. In other words, the pressure is higher at the inlet of the regenerating apparatus than at the outlet of the stripping apparatus, and the catalyst does not flow from the stripping apparatus to the regenerating apparatus.

To cope with this, if the height of the dense layer of the stripping apparatus is increased, the static pressure on the stripping apparatus side also increases. In that case, however, the distance over which the catalyst must be lifted increases, and as a result, the catalyst must be lifted. This is not a solution because the pressure loss associated with lift-up also increases. On the other hand, if the pressure on the stripping device side is increased, the stripping device is connected to the upper part of the regenerator via the reactor when going back the flow of the catalyst circulation, and if the pressure of the stripping device is increased, the regenerator is increased. The pressure at the upper part of the regenerating apparatus is also increased, and the pressure at the air inlet for regeneration at the lower part of the regenerating apparatus is also increased. Increasing the amount of combustion air blows reduces the density of the catalyst in the regenerator and reduces pressure loss, but increases the amount of air used, which is economically undesirable. Also, Japanese Patent No. 25233
No. 25 also has the same problem in that regeneration air is introduced from the lower part of the regenerator to lift the catalyst to the height of the reactor inlet.

As described above, in a circulating fluidized bed reaction system using a downflow reactor, while minimizing the amount of air and the like used, pressure balance is achieved by a circulation cycle of a reactor, a stripping device, a regenerator and a reactor again. There are considerable difficulties to keep. It is particularly difficult for an apparatus having a large amount of circulating solids because the power required to lift up the solids is large.

[0009] Processes that aim to increase the selectivity of the preferred product with short contact times often use high mixing ratios to keep the contact time as short as possible and to maintain high conversion. As a circulating fluidized bed reaction system, a system that has a simple structure, does not require a solid transfer gas, and is easy to maintain the pressure balance to smoothly circulate the solid has been required together with a catalytic cracking method that utilizes this. .

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has a simple structure, does not require a gas for transferring solids, and maintains a pressure balance for smoothly circulating solids. It is an object of the present invention to provide a low-cost, high-quality catalytic cracking method for hydrocarbonaceous oils by using a circulating fluidized bed reaction system including a down-flow type reactor having the advantage of low cost. .

[0011]

In order to solve the above problems,
In the catalytic cracking method of the present invention in which a hydrocarbon oil such as heavy oil and a fluid catalytic cracking catalyst composed of silica alumina or the like are brought into downflow contact, (a) the fluid catalytic cracking catalyst (ct)
A vertical downflow type moving bed reactor (12) supplied with
The superficial velocity of the stripping inert gas following the vertical downflow type moving bed reactor (12) is 0.03-0.
Thick fluidized bed stripping device set at 7 m / s
(13) and (c) a thick fluidized bed type regenerator (14) in which the fluid catalytic cracking catalyst (ct) from the stripping device (13) is introduced at a half of the device height. At the higher part,
The pressure at the inlet from the stripping unit (13) is (P), the top pressure of the rich fluidized bed regenerator (14) is (PT), the tower of the dense fluidized bed regenerator (14) is Assuming that the top pressure is (PB), it is connected to a position where P ≦ (PT + PB) / 2, and the superficial velocity of the regeneration air is 0.
A rich fluidized bed regenerator (1 to 1.5 m / s)
4) and (d) the fluidized catalytic cracking catalyst connected to the upper portion of the rich fluidized bed regenerator (14) and the entire amount of the fluidized catalytic cracking catalyst and regeneration air in the rich fluidized bed regenerator are received, and the fluidized contact cracker is passed through the upper end portion. The superficial velocity of the regeneration air for circulating and supplying the cracking catalyst (ct) to the vertical downflow type moving bed reactor (12) is 2 to 2
And an upflow regenerator (15) comprising a medium-to-high-speed dilute moving bed set at 0 m / s.

Alternatively, (a) a vertical downflow type moving bed reactor (12) to which the fluid catalytic cracking catalyst (ct) is supplied from above.
(B) The superficial velocity of the stripping inert gas downstream of the vertical downflow type moving bed reactor (12) is 0.
A thick fluidized bed stripper (13) set at 03-0.7 m / s; and (c) a thick fluidized bed regenerator (14).
Wherein the inlet for introducing the fluid catalytic cracking catalyst (ct) introduced from the stripping apparatus (13) through the stand pipe (26 ') is a portion lower than 1/2 of the apparatus height,
The pressure at the inlet from the stripping device (13) is (P), the top pressure of the rich fluidized bed regenerator (14) is (PT), and the pressure of the rich fluidized bed regenerator (14) is When the top pressure is (PB), it is connected to a position where P> (PT + PB) / 2, and the superficial velocity of the regeneration air is 0.
A rich fluidized bed regenerator (1 to 1.5 m / s)
4), the fluid catalytic cracking catalyst (ct) from the stripping device (13) is connected to a portion whose inlet is lower than 1/2 of the device height, and the superficial velocity of the regeneration air is 0.1 ~ 1.5
a thick fluidized bed regenerator (14) set to m / s,
(D) The fluid catalytic cracking catalyst (ct ) To the vertical downflow type moving bed reactor (12) is circulated, and the superficial velocity of the regeneration air is 2 to 20 m / m2.
and an upflow regenerator (15) comprising a medium-to-high-speed dilute moving bed set to s.

In each of the above methods, the contact time in the vertical downflow type high-speed moving bed reactor (12) is set to 0.1 to 0.1.
The objective is achieved by setting the catalyst / oil ratio to 2.0 to 50 seconds, setting the temperature at the outlet of the reactor to 530 to 700 ° C., and setting the introduced catalyst / oil ratio to 10 to 50.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the catalytic cracking system according to the present invention, a stripping device is arranged below a downflow type reactor, and the stripping speed of the inert gas for stripping is controlled to be low so that the stripping is performed. The static pressure of the dense fluidized bed in the apparatus is increased as much as possible. The regenerator is also used as a transfer medium for lifting solids by combining a thick fluidized bed regenerator with a medium-speed moving bed upflow regenerator connected above it. ing. This method allows the solid to be lifted up to the top of the device with a small pressure drop. Further, the introduction of the catalyst from the stripping device to the rich fluidized bed type regenerator is avoided at the lower part of the rich fluidized bed type regenerator where the pressure is increased by the static pressure of the catalyst in the regenerating device. Installed on top of the playback device. In the method of the present invention, the catalytic cracking of the hydrocarbon oil is performed by using such a system while maintaining predetermined conditions in each part of the system. By taking the above measures, there is no need to supply extra gas for transporting solids with a simplified flow,
In addition, it is possible to establish a circulation of solids while maintaining a pressure balance without increasing the height of the entire apparatus, so that suitable catalytic cracking of hydrocarbon oil can be performed. Then, in the method of the present invention, the catalytic cracking of the hydrocarbonaceous oil can be performed using the above-described system while maintaining predetermined conditions in each part of the system.

Alternatively, as another catalytic cracking system, a part of a solid introduction pipe from the stripping device to the rich fluidized bed type regenerating device is formed as a stand pipe, and the static pressure of the solid in the stand pipe is utilized. A device for introducing solids from the stripping device into a high pressure portion below the dense fluidized bed regenerator is used. Also in this method, the same suitable catalytic cracking of hydrocarbonaceous oil as in the above embodiment can be performed.

[Embodiment] The method of the present invention will be described with reference to the drawings. FIG. 1 shows a typical connection example of a reaction system used in the present invention. Hereinafter, an embodiment of the method of the present invention in which the system configuration and the conditions of each part of the system are matched will be described in detail. In this system, a hydrocarbon oil such as heavy oil is used as a catalytic cracking catalyst supplied from above in a well-known vertical downflow type high-speed moving bed reactor (12) using a particulate solid such as silica alumina. Decomposition reaction.
The product gas is separated by a separator (10) connected to the reactor (12), and extracted out of the system through a line (24). A powdery solid, which is a catalyst, is a vertical downflow type high-speed moving bed reactor (12), a stripping device (13), a rich fluidized bed type regenerator (14), a medium-high speed moving bed upflow type regenerator ( 15)
(Hereinafter referred to as riser regeneration device), feed hopper
(16), and circulates again in the system in the order of the reactor (12). In addition, the hydrocarbon as a raw material is supplied to the injector (18) through the line (22). The raw material is a gas or a liquid. If the raw material is a liquid, most of the raw material is vaporized when mixed with the solid by the injector (18).

From the vertical downflow type high-speed moving bed reactor (12) to the high-speed separator (10) connected below, hydrocarbon gas as a reaction product and a particulate solid (catalyst) are added. Is supplied. The gas from which most of the solids have been removed by the high-speed separator (10) is first led to the secondary separator (19). Here, a small amount of solid remaining in the gas is removed, taken out of the system through a line (24), and led to a product recovery system including a distillation column and the like. A tangential cyclone is preferred as the secondary separator. When it is not necessary to shorten the contact time, the high-speed separator 10 may be omitted, and the mixture of the solid and the product gas may be directly introduced into the tangential cyclone. On the other hand, the solid removed by the high-speed separator (10) is guided to the stripping device (13) through the dipreg (11).

In the stripping device (13), the solid forms a thick layer, and hydrocarbons remaining on or between the solids are removed by an inert gas such as steam introduced from the line (20). This hydrocarbon passes through line (23) together with an inert gas such as steam, and a product recovery system (not shown)
Led to. The superficial velocity of the inert gas in the stripping device is preferably from 0.03 to 0.7 m / s. If the superficial velocity of the inert gas is less than 0.03 m / s, it is not preferable because the flow becomes incomplete or the stripping becomes incomplete. More preferably 0.07 to
A speed of 0.3 m / s is used. If it is more than 0.3 m / s, the density of solids in the stripping device is reduced, and the static pressure of the solid is reduced. As a result, the pressure at the lower part of the stripping device (13) is reduced, so that the stripping device (13) It is not preferable because the solid cannot be smoothly introduced into the thick fluidized bed type regenerating apparatus (14).

Subsequently, the solid extracted from the lower part of the stripping device (13) is introduced into a rich fluidized bed type regenerating device (14) through a line (26) through a valve (32) for adjusting a flow rate. Is done. In particular, the rich fluidized bed regenerator (1
The position of connection to 4) is a position avoiding the lower part of the dense fluidized bed regenerator (14) where the pressure is high due to the static pressure of the solid in the apparatus, that is, 1 / H of the height of the dense fluidized bed regenerator. It is connected to the part higher than 2, that is, the upper half of the rich-bed type regenerator (14) where the gradient distribution pressure in the column is sufficiently low, so that solids can be easily introduced from the stripping unit (13). It has become possible. The inside of the dense layer can be regarded as a completely mixed layer. Even if the line (26) is connected to the upper half of the rich fluidized bed type regenerator (14), the solid regeneration efficiency does not decrease. In addition, when a part of the line (26) is formed as a standpipe, the connection position to the thick fluidized bed type regenerating apparatus can be further lowered, which will be described later in detail.

In the regenerator (14), a solid is
The carbonaceous matter adhering to the solids and the undecomposed hydrocarbon oil that could not be completely removed by the stripping device are burned, and the solids are regenerated. At this time, the superficial velocity of the regeneration air inside the regeneration device (14) is set and maintained at about 0.1 to 1.5 m / s. If the superficial velocity of the regeneration air is smaller than 0.1 m / s, the flow becomes incomplete and the combustion efficiency is lowered, which is not preferable. on the other hand,
If it is higher than 1.5 m / s, it is not preferable because the flow rate of the combustion air needs to be increased unnecessarily. More preferably, a range of 0.3 to 1.0 m / s is used. Incidentally, the diameter of the regenerator (14) can be reduced without changing the flow rate of the combustion air to make the superficial velocity of the regenerative air higher than 1.5 m / s. In order to secure the residence time, the height of the reproducing device (14) must be increased. As a result, the height of the entire apparatus is increased, which leads to an increase in cost, which is not preferable.

The upper part of the regenerating device (14) is connected to a riser type regenerating device (15) as an upflow type regenerating device composed of a medium-to-high-speed lean moving layer as it is, and is supplied to the rich layer type regenerating device (14). The entire amount of the solid and the regeneration air is directly introduced into the riser type regeneration device (15). Riser type playback device
The diameter of (15) is smaller than that of the rich layer type regenerating apparatus (14), and the superficial velocity of the regenerating air is adjusted and set to be 2 to 20 m / s. If the superficial velocity of the combustion air is less than 2 m / s, the density of solids in the riser regeneration device (15) increases, and the pressure loss of the riser regeneration device (15) increases, which is not preferable. Conversely, the superficial velocity is 2
If it is greater than 0 m / s, the friction between the mixed flow of gas and solid and the wall of the riser regenerator (15) is increased, so that the pressure loss is increased and the abrasion is increased.

The superficial velocity of the combustion air in the riser regeneration device (15) is more preferably 3 to 5 m / s. Therefore, the solid and air which have formed a thick fluidized bed in the rich bed type regenerating apparatus (14) form a medium speed moving layer or a high speed moving bed in the riser type regenerator (15). As a result, in the riser type regenerator (15), the density of the solid is low and the static pressure of the solid is low. For this reason, it is possible to lift up the solid to the upper part of the apparatus with a small pressure loss.

The regeneration air is also used as a solid transfer medium by squeezing the upper portion of the rich layer type regenerator (14) and connecting it to the riser type regenerator (15). Therefore, there is no need to separately supply a transfer medium for lifting up solids, and the capacity of the air supply means such as a blower can be minimized. Therefore, the apparatus is simplified, operation is facilitated, and it is economically preferable.

[0024] The oxygen in the combustion air is rich in a layer type regeneration device (1).
If all are consumed in 4), air is simply a medium for transferring solids in the riser type regenerator (15), and if all oxygen in the combustion air is not consumed in the rich layer type regenerator (14),
Combustion also occurs in the riser type regenerator (15), and the air is used not only for combustion but also as a medium for transferring solids. Of course, in order to further promote the combustion, it is of course good to further supply regeneration air at the inlet of the riser type regeneration device. It is also possible to circulate the solids from the feed hopper (16) to the rich regeneration unit (14) through the line (27) in order to easily control the amount of solids circulated.

In general, in an apparatus using a downflow type reactor, it is indispensable to lift solids that have fallen in the lower part of the apparatus in the reactor to the upper part of the apparatus. The transfer power is obtained, and the economic advantage is great.

The solids ejected from the upper part of the riser type regenerator are temporarily stored in a feed hopper (16), then introduced into an injector (18), and mixed with a hydrocarbon raw material supplied again through a line (22). The reaction is performed in the reactor (12). On the other hand, the regeneration air is discharged through a line (25) through a separation device (17) composed of a tangential cyclone or the like. It should be noted that the feed hopper (16) may be omitted under such a condition that air leakage from the riser type regenerator (15) to the injector (18) can be prevented by a combination of a valve and a standpipe.

Looking at the pressure balance of the entire apparatus according to the embodiment described above, the pressure starts counterclockwise in FIG. 1 starting from the outlet (lower part) of the stripping device (13) and ending at the inlet (upper part) of the stripping device. It gradually decreases. The factors are valve (32), riser regeneration device (15), valve (31),
This is a pressure loss in the injector (18), the reactor (12), the high-speed separator (10), and the like. Then, as it is, the pressure in the lower part is higher than that in the upper part of the stripping device (13), that is, the pressure increases in the direction of flow, and the solid circulation is not established. What eliminates this pressure difference is the static pressure of the solid dense fluidized bed in the stripping device (13).
For this reason, the circulation of solids cannot be performed in a setting in which the pressure loss from the thick layer type regenerating apparatus to the separator increases and becomes larger than the static pressure of the stripping apparatus.

The conditions for establishing solids circulation in the above-described apparatus are therefore: the height of the dense fluidized bed of the stripping unit (13): Hs (m), the density of the dense fluidized bed of the stripping unit (13) Is: ρs (g / cm 3), the height of the fluidized bed of the riser regeneration unit (15) is: Hr (m), the density of the fluidized bed of the riser regeneration unit (15) is: ρr (g / cm 3), and the valve ( 31), (32): ΔPb (kg / cm 2),
Pressure loss of other parts: ΔP '(kg / cm 2),
Hs × ρs / 10> Hr × ρr / 10 + ΔPb × 2 + ΔP ′ (1)

As is clear from FIG. 1, Hr increases as Hs increases. The relationship is represented by the following equation. Hr = Hs + ΔH (2) ΔH is the height occupied by the reactor (12) and the like, and there is no flexibility in designing the system. Using the expression (2), the expression (1) is expressed as the following expression. Hs (ρs−ρr)> ρr × ΔH + ΔPb × 2 + ΔP ′ (3) ΔPb is determined by the performance of the valve, and is generally 0.1 to
It is about 0.5 kg / cm2 and there is no flexibility. .DELTA.P 'is generally about 0.1 to 0.3 kg / cm @ 2, which also has no flexibility. After all, when (ρs−ρr) becomes small, Hs
Is large, that is, the height of the entire device is large. Higher equipment leads to higher construction costs.

In the present invention, the stripping device (13)
And controlling the gas superficial velocity in the riser regeneration device (15) to 0.03 to 0.7 m / s and 0.1 to 1.5 m / s, respectively, to maximize ρs and minimize ρr. This makes it possible to perform an optimal design with Hs as small as possible. Generally, the solid density in the stripping device (13) is measured by a riser regeneration device (15).
The desired condition can be obtained by maintaining the solid density within 0.5 to 0.75 g / cm3.

By the way, a target system can be obtained by another configuration similar to the embodiment described above. That is, as an alternative, in a system substantially similar to that of FIG.
′), The connection position of the line (26) to the rich fluidized bed regenerator (14) is lower than half the height of the device (14), that is, the rich fluidized bed regenerator (14) It is also possible to make the lower half. The standpipe in the present invention refers to a pipe portion filled with a solid that is vertical or has an inclination of 45 degrees or less from the vertical. The stand pipe (26 ') is supplied with a minimum amount of gas necessary for flow, or no gas is supplied at all and the density of solids is maximized. By setting the height of the stand pipe to 1/2 or more of that of the rich fluidized bed regenerator (14), the pressure at the lower part of the line (26) can be increased by the static pressure of the solid in the stand pipe, Even when solids are introduced into the lower half of the fluidized bed type regenerator (14), the same operation and effects as those of the system shown in FIG. 1 can be obtained and stable solid circulation can be maintained.

Hereinafter, the results obtained for actual experimental examples to which the present invention is applied will be described.
The set values and the like do not limit the present invention at all. [Experimental example 1]; bulk density 0.85 g / cm3 as a solid
In a device equivalent to that shown in Fig. 1 using the catalyst for fluidized catalytic cracking, the height of the dense fluidized bed of the stripping device (13) is 9 m, and the linear velocity of the stripping steam is 0.1 m.
/ S, the height of the rich fluidized bed regenerator (14) is 1 m, the air linear velocity for combustion is 0.6 m / s, the height of the riser type regenerator is (14) m, and the air linear velocity for combustion is 3 At 0.6 m / s, stable catalyst circulation was established. At this time, the catalyst density in the stripping device (13) was 0.77 g / c.
m3, the catalyst density in the rich fluidized bed regenerator
The catalyst density in the riser type regenerator (15) was 3 g / cm @ 3 and 0.07 g / cm @ 3. Valves (31), (3
The pressure loss in 2) was 0.1 kg / m2. Also, the line (26) is 0.2
m place. At this time, hydrogenated vacuum gas oil was used as a raw material to be supplied to the reactor (12). Reactor
The catalyst / oil ratio in (12) was 20, the outlet temperature of the reactor (12) was 600 ° C., and the contact time was 0.5 seconds. The reaction results are shown in Table 1 below. At this time, the carbon concentration of the pre-regenerated catalyst taken out of the line (26) was 0.21% by weight, and the carbon concentration of the post-regenerated catalyst taken out of the feed hopper (16) was 0.01%.
% By weight.

[0033]

[Table 1]

[Comparative Example 1] Under the same operating conditions as in Experimental Example A1, when only the superficial velocity of the stripping inert gas was changed to 0.2 m / s, it was taken out of the line (26) before regeneration. Since the carbon concentration of the catalyst was increased to 0.3% by weight and the heat of combustion in the regenerator increased, the apparatus was stopped.

[Comparative Example 2]: Under the same operating conditions as in Experimental Example A1, only the superficial velocity of the regeneration air in the rich fluidized bed type regenerator (14) was changed to 0.08 m / s. The carbon concentration of the regenerated catalyst taken out from 16) increased to 0.03% by weight. As the operation continued, the temperature increased further, and the apparatus was stopped because the conversion in the reactor (12) decreased.

[Comparative Example 3]; Under the same operating conditions as in Experimental Example A1, only the superficial velocity of the regeneration air of the rich fluidized bed type regenerator (14) was changed to 3 m / s. Since the oxygen concentration increased and sufficient air was used for the air required for combustion, it was found that it was not economically favorable.

As described above, in the present invention, the stripping device is disposed below the downflow type reactor, and the superficial velocity of the stripping inert gas is controlled to be low.
The point that the static pressure of the dense fluidized bed in the stripping device was increased as much as possible, and the regenerating device combined with the rich fluidized bed type regenerating device and the medium-speed moving bed upflow type regenerating device connected above it Techniques such as utilizing the working air as a transfer medium for lifting up solids can also lift solids up to the top of the device with low pressure loss. Further, the introduction of the catalyst from the stripping apparatus to the rich fluidized bed type regenerator is avoided at the lower part of the rich fluidized bed type regenerator where the pressure is increased by the static pressure of the catalyst in the regenerating apparatus. Introduced to the upper part of the die regeneration device, the above-mentioned measures and optimization of the setting conditions of each part make the structure simple and eliminates the need for a gas for transferring solids. The initial object of catalytic cracking of a suitable hydrocarbonaceous oil has been achieved by using a circulating fluidized bed reaction system including a downflow reactor having the advantage of easily maintaining a pressure balance for circulation. Alternatively, a part of a solid introduction pipe from the stripping device to the dense fluidized bed type regenerating device may be formed as a standpipe, and the static fluid pressure of the solid in the standpipe may be used to form the solid fluidized bed type regenerating device. It is possible to introduce the solids from the stripping device into the high pressure part at the lower part of the regenerating device with the same result.

[0038]

According to the present invention, as described above,
(A) a vertical downflow type moving bed reactor (12) to which the fluid catalytic cracking catalyst (ct) is supplied from above, and (b) a downward flow following the vertical downflow type moving bed reactor (12). A thick fluidized bed stripping apparatus (13) in which the superficial velocity of the stripping inert gas is set to 0.03 to 0.7 m / s;
(C) In the rich fluidized bed regenerating apparatus (14), the inlet for introducing the fluid catalytic cracking catalyst (ct) from the stripping apparatus (13) is connected to a position higher than 1/2 of the apparatus height. A dense fluidized bed regenerator (14) in which the superficial velocity of the regeneration air is set to 0.1 to 1.5 m / s, and (d) an upper part of the dense fluidized bed regenerator (14). It is connected and receives the entire amount of the fluid catalytic cracking catalyst and the regeneration air in the rich bed type regenerating apparatus and passes the fluid catalytic cracking catalyst (ct) via the upper end to the vertical downflow type moving bed reactor (12). An upflow regenerator (15) consisting of a medium-to-high-speed dilute moving bed in which the superficial velocity of the regenerating air for circulating and supplying is set to 2 to 20 m / s. Pressure balance for smooth solid circulation without the need for a solid transfer gas. By using suitable CFB system comprising the benefits of easy lifting is, it is possible to obtain a high quality product at a low running cost perform catalytic cracking of suitable hydrocarbonaceous oils. In addition, the same effect can be obtained by a system having a configuration in which the above-described stand pipe having substantially the same configuration is added and the corresponding connection position is changed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a circulating fluidized bed system according to the method of the present invention.

[Description of Signs] (10) High-speed separator, (12) Downflow moving bed reactor, (13) Rich fluidized bed stripping device, (14) Rich fluidized bed regeneration device, (15) )… Upflow regenerator (riser regenerator), (16)… Feed hopper, (17)… Separator, (18)… Injector, (19)… Secondary separator, (31)… Valve, (32) )… Valve, (26 ′)… Stand pipe, (ct)… Catalyst (fluid catalytic cracking catalyst).

Claims (3)

[Claims] 1. A method for catalytically cracking a hydrocarbon oil, such as heavy oil, which is brought into downflow contact with a fluid catalytic cracking catalyst composed of silica alumina or the like, comprising: A vertical downflow moving bed reactor (12) to which a catalyst (ct) is supplied, and (b) the vertical downflow moving bed reactor
(13) a thick fluidized bed type stripping apparatus (13) in which the superficial velocity of the stripping inert gas succeeding below (12) is set to 0.03 to 0.7 m / s; A mold regeneration device (14), wherein the inlet for introducing the fluid catalytic cracking catalyst (ct) from the stripping device (13) is at a portion higher than 1/2 of the device height, wherein the stripping device (13 ), The pressure at the inlet is (P), the pressure at the top of the rich fluidized bed regenerator (14) is (PT), and the pressure at the top of the rich fluidized bed regenerator (14) is (PB). , Where P ≦ (PT + PB) / 2, and the superficial velocity of the regeneration air is 0.
A rich fluidized bed regenerator (1 to 1.5 m / s)
4) and (d) the fluidized catalytic cracking catalyst connected to the upper portion of the rich fluidized bed regenerator (14) and the entire amount of the fluidized catalytic cracking catalyst and regeneration air in the rich fluidized bed regenerator are received, and the fluidized contact cracker is passed through the upper end portion. The superficial velocity of the regeneration air for circulating and supplying the cracking catalyst (ct) to the vertical downflow type moving bed reactor (12) is 2 to 2
A catalytic cracking method for hydrocarbon oils, comprising using an upflow regenerator (15) comprising a medium-to-high-speed lean moving bed set to 0 m / s. 2. A method for catalytic cracking of hydrocarbon oil in which a hydrocarbon oil such as heavy oil and a fluid catalytic cracking catalyst composed of silica-alumina or the like are brought into downflow contact with the hydrocarbon oil. A vertical downflow moving bed reactor (12) to which a catalyst (ct) is supplied, and (b) the vertical downflow moving bed reactor
(13) a thick fluidized bed type stripping apparatus (13) in which the superficial velocity of the stripping inert gas following downward is set to 0.03 to 0.7 m / s; The inlet for introducing the fluid catalytic cracking catalyst (ct) which is introduced from the stripping apparatus (13) through the stand pipe (26 ') from the stripping apparatus (14) is 1/1 of the apparatus height. In a portion lower than 2, the pressure at the inlet from the stripping device (13) is (P), the overhead pressure of the rich fluidized bed regeneration device (14) is (PT), and the rich fluidized bed regeneration is When the pressure at the top of the apparatus (14) is (PB), it is connected to a position where P> (PT + PB) / 2, and the superficial velocity of the regeneration air is 0.
A rich fluidized bed regenerator (1 to 1.5 m / s)
4), the fluid catalytic cracking catalyst (ct) from the stripping device (13) was connected to a portion whose inlet was lower than 1/2 of the device height, and the superficial velocity of the regeneration air was 0.1 ~ 1.5
a thick fluidized bed regenerator (14) set to m / s,
(D) The fluid catalytic cracking catalyst (ct) is connected to the upper part of the rich fluidized bed regenerator (14), receives the entire amount of the fluid catalytic cracking catalyst and regeneration air in the rich fluidized bed regenerating apparatus, and receives the fluid catalytic cracking catalyst (ct ) To the vertical downflow type moving bed reactor (12) is circulated, and the superficial velocity of the regeneration air is 2 to 20 m / m2.
(c) an upflow regenerator (15) comprising a medium-to-high-speed lean moving bed set to s. 3. The vertical downflow type high-speed moving bed reactor (12).
At 0.1 to 2.0 seconds at a catalyst / oil ratio of 1
0-50, the temperature at the reactor outlet is 530-700
° C and the introduced catalyst / oil ratio is 10 to
The catalytic cracking method of a hydrocarbonaceous oil according to claim 1 or 2, wherein the catalytic cracking is 50.