JPS5850675B2 - Heavy oil decomposition method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cracking heavy oil, and more specifically, the present invention relates to a method for decomposing heavy oil, and more specifically, it involves suspending a fine particulate hydrotreating catalyst (hereinafter simply referred to as a suspension catalyst) for heavy oil. , relates to a method for cracking heavy oil, which is characterized by subjecting the oil to hydrotreatment under pressurized hydrogen pressure and catalytically cracking the resulting treated oil containing a suspended catalyst.

Light oil is separated from crude oil, such as atmospheric distillation residue oil,
Heavy oils such as vacuum distillation residue oil and deasphalting residue oil contain most of the metals, asphaltenes, and residual carbon that are found in crude oil, and also have high concentrations of sulfur and nitrogen. included in.

For this reason, while distillate oils such as light oils, either as they are or after being further refined, have a wide range of uses and are in high demand as petrochemical raw materials and internal combustion engine fuels, the uses of heavy oils are limited.

In other words, heavy oil can be used as fuel oil after being subjected to hydrodesulfurization treatment, or metals and residual carbon can be separated as coke or pitch through treatments such as coking through thermal decomposition, and the light oil obtained at the same time can be used as fuel oil. Just use it.

However, when residual oil is thermally decomposed, coke obtained as a by-product contains large amounts of sulfur and nitrogen, so its uses are extremely limited.

Therefore, at a time when petroleum products are becoming more valuable as liquid fuels, the conventional thermal decomposition method for heavy oil as described above is not necessarily an advantageous treatment method.

On the other hand, the hydrodesulfurization method for heavy oil has been implemented on a large scale industrially to obtain low-sulfur heavy oil.

However, it is extremely difficult to hydrocrack heavy oil such as residual oil mainly for the purpose of obtaining light oil, and it also requires extremely large amounts of chemical hydrogen consumption, making it both industrially and economically difficult. Not considered advantageous.

The process of catalytic cracking of crude oil distillate to produce primarily high octane Kallin is carried out on a large scale.

On the other hand, it is technically possible to subject heavy oil to catalytic cracking, and this has been carried out industrially, albeit on a small scale.

However, this method has drawbacks such as not only high yields of gas and coke, but also severe deterioration of the catalyst and high sulfur and nitrogen content of the produced oil.

In order to eliminate these drawbacks, a method is known in which raw material heavy oil is thoroughly hydrodesulfurized and demetalized in advance and the resulting oil is subjected to catalytic cracking.

However, in the hydrodesulfurization method using a conventional stationary reactor, the properties of the produced oil change as the catalyst deteriorates, so it is difficult to keep the properties and yield of the light oil obtained from the catalytic cracking process constant. Have difficulty.

As an improvement to the hydrodesulfurization-catalytic cracking method for heavy oil, U.S. Pat.
A method has been proposed whereby feed oil to a catalytic cracking process with constant properties can be obtained.

The conventionally known hydrodesulfurization-catalytic cracking cracking method for heavy oil has the following basic problems and drawbacks.

That is, (1) in the hydrodesulfurization step, if desulfurization and demetallization are performed to a level sufficient to perform the next catalytic cracking step in a stable state, desulfurization will be performed more thoroughly than necessary.

The chemical hydrogen consumption required for hydrodesulfurization is usually proportional to the amount of desulfurization, so if thorough demetalization is performed, more hydrogen than necessary will be consumed.

(2) The amount of catalyst and the size of the reactor required for hydrodesulfurization are proportional to the amount of metal in the heavy oil to be treated.

Therefore, the processing capacity of the hydrodesulfurization process is determined by the properties of the raw material heavy oil, and as a result, the processing capacity of the catalytic cracking process is determined by the properties of the heavy oil, making steady operation difficult.

(3) The properties of hydrotreated oil change as the catalyst deteriorates.

Therefore, fluctuations in the operating conditions of the catalytic cracking process, light oil yield, light oil properties, etc. are unavoidable.

According to the present invention, by suspending fine solid particle i-shaped hydrotreating catalyst in heavy oil, the hydrogen pressure is 10 to 350 Ky/all,
A hydrotreating step in which the hydrotreating process is carried out at a temperature of 420 to 470°C, and the treated oil in which the hydrotreating catalyst obtained in the hydrotreating process is suspended is heated at a temperature of 430 to 530°C in the presence of a cracking catalyst.
A method for cracking heavy oil is provided, which includes a catalytic cracking step of catalytically cracking at .degree.

The method of the invention will now be described in detail.

Heavy oils used in the method of the present invention include atmospheric distillation residues, vacuum distillation residues, and deasphalting residues thereof, but tar sand bitumen, oil cool, coal liquefied oil, and even crude oil, which have a high proportion of residues, can be used as heavy oils. etc. can also be applied.

Heavy oil is first hydrotreated under high temperature and pressure of hydrogen in the presence of a suspended catalyst.

There are no particular restrictions on the composition and properties of the suspension catalyst, and ordinary hydrogenation catalysts can be used.

As will be described in detail later, it is also possible to use a fine solid particle catalyst obtained by regenerating and fractionating the catalyst components extracted from the catalytic cracking process.

The amount of suspended catalyst relative to raw material heavy oil is determined by taking into consideration prevention of coking in the reactor, ease of handling of the suspended reaction mixture, etc., but usually 0.
2 weight φ or more, preferably 0.5 weight φ or more and 20 weight φ or less.

When a high reaction rate is obtained by performing the reaction at a relatively low hydrogen pressure and high temperature, the amount of O is usually 15 to 10% by weight, preferably 1%.
~5 weight section.

When a part of the heavy components containing suspended catalyst obtained by distilling the hydrotreated oil as described below is recycled to the hydrotreating process, in order to prevent coking in the reactor, Catalyst concentration at reactor inlet is 5~ with new catalyst
Sometimes it is made into a 20-weight steamed bun.

Hydrogen pressure in hydrotreating is usually 10 to 350 kg/c
IIl, preferably 50 to 200 KP/d, and the temperature is usually 420 to 470°C, preferably 430 to 460°C.

These reaction conditions are interrelated; high hydrogen pressure allows processing at high temperatures, while low hydrogen pressure allows processing at low temperatures to avoid coking.

If the raw material heavy oil H10 ratio is low and the asphaltene concentration or residual carbon concentration is high, high hydrogen pressure,
A low temperature is chosen.

On the other hand, when the H10 ratio is high and the concentration of asphaltene is low, the treatment can be carried out under high temperature and low hydrogen pressure conditions.

The liquid-space velocity change in hydrotreating varies depending on the properties of the raw material heavy oil, the recycle ratio of the treated oil heavy components, hydrogen pressure, etc., which will be described later, and is determined according to the reaction temperature.

For example, if vacuum residue oil with a boiling point of 500 to 550°C or higher is used as raw material heavy oil and there is no circulation of processed oil heavy components (recycle ratio: O), the processing temperature is 0.2 to 0.7 at 440°C.
1/Hr, and at 450°C, it is about 0.4 to 1.21/Hr.

In addition, in the case of normal pressure residual oil with a boiling point of 300 to 400 °C or higher, at 440 °C, 0.4 to 1.41 / Hr, 450
℃, it varies by about 0.7 to 2.01/Hr.

The volume ratio of hydrogen to raw material heavy oil is i,ooo~5,0
It is about 00.

The reaction mixture obtained by hydrotreating is separated into treated oil containing a suspended catalyst and gas by gas-liquid separation.

The gas is sent to a recycling gas treatment process where it is separated into hydrogen, backwater hydrogen, ammonia and light hydrocarbons, and the recovered hydrogen is recycled to the hydrotreating process.

The treated oil is fed to the next catalytic cracking step without substantially separating and removing the suspended catalyst contained therein.

One of the features of the present invention is that this eliminates the technically most difficult catalyst separation and recovery steps in processes involving hydrotreating steps using suspended catalysts.

Therefore, the hydrotreated oil may be distilled, the light components separated, and the remaining heavy components, including the suspended catalyst, fed to a catalytic cracking step.

Separation treatment of light components and heavy components is carried out by atmospheric distillation, atmospheric distillation,
Silk combination with vacuum distillation or solvent deasphalting treatment, etc.
This can be done by any known method.

Such fractionation of hydrotreated oil is useful when improving the yield of middle distillates such as kerosene and diesel oil other than gasoline fractions, and/or by recycling a part of heavy components to the hydrotreating process. It is used to improve the metal removal rate.

That is, by providing a distillation treatment step for the hydrotreated oil, it is possible to obtain the kerosene oil component with a small amount of aromatic components produced in the hydrotreatment step as a middle distillate in a relatively high yield.

Since this middle distillate has a low aromatic component, it can be easily hydrorefined into high-quality petrochemical naphtha, kerosene, diesel fuel, etc., and can also be used as is for these purposes.

Although it is possible to increase the yield of middle distillates using ordinary heavy oil catalytic cracking or hydrodesulfurization-catalytic cracking methods, in this case, the aromatic component content of the resulting middle distillate may be increased. The amount is large and it cannot be used as high-quality kerosene oil.

Although kerosene with hydrogenated aromatic components can be obtained by hydrogenolysis under severe reaction conditions, a large amount of hydrogen is required in this case.

Therefore, the method of the present invention is extremely excellent not only as a method for simply lightening heavy oil, but also as a method for obtaining high-quality middle distillates according to demand.

The heavy component containing the clouded catalyst obtained by separation of the hydrotreated oil is sent to the catalytic cracking step, but a portion thereof may be recycled to the hydrotreating step as mentioned above.

Such a circulation process is particularly suitable for treating inferior oils with a high metal content and/or residual carbon content, thereby making it possible to obtain gasoline fractions and/or middle distillates in high yields. Become.

When this circulation step is provided, it is preferable to use column bottom oil as the heavy component to be circulated.

The separated light fraction may be used as a raw material for kerosene oil, or in order to increase the yield of gasoline fraction etc., at least a part of it may be supplied to the catalytic cracking process together with the heavy fraction. good.

The boiling point range and recovery rate of each middle distillate separated as a side stream from the hydrotreated oil can be arbitrarily determined depending on the demand for the product.

When recycling heavy components, the ratio of recycled oil to new heavy oil feedstock (recycle ratio) depends on the hydrocracking rate in the hydrotreating process, the properties of the raw material, and the yield rate of each middle distillate product. It can be decided arbitrarily depending on the situation.

For example, when the feedstock oil contains a large amount of metals, when increasing the yield of kerosene fraction as a side stream, or when reducing the amount of suspended catalyst supplied to the catalytic cracking process along with the treated oil. A large recycling ratio is selected in cases such as when reducing the burden of the step of separating and recovering suspended catalyst from a catalytic cracking catalyst, which will be described later.

On the other hand, in cases where the metal content of the feedstock oil is relatively low, a small recycling ratio may be sufficient.

If the recycling ratio is increased, the equipment for separating the light and heavy components of the hydrotreated oil and its operating cost will increase, and the amount of coke deposited on the suspended catalyst contained in the circulating oil will increase. In addition, the catalyst particles tend to aggregate, which makes the reactor more likely to be clogged by coking.

For these reasons, a large recycling ratio is not necessarily profitable.

Therefore, the recycling ratio is usually 3.0 or less, preferably 0.
It is 2-1.

In addition, when circulating heavy components, the single flow cracking rate in the hydrotreating process is set relatively low, and the boiling point in the supplied oil is 500 to 500.
The reduction rate of the vacuum residue at 550°C or higher is set to be in the range of 40 to 80%, preferably 50 to 70%, at the inlet of the hydrogenation reactor.

The treated oil containing the suspended catalyst from the hydrotreating process as described above is supplied to the catalytic cracking process.

The properties of the feedstock to be fed to the catalytic cracking process vary widely depending on the properties of the feedstock heavy oil, the reaction conditions in the hydrotreating process, the circulation ratio of heavy components, etc. Controlling the metal content is most important from the viewpoint of poisoning the catalytic cracking catalyst.

In the method of the present invention, the hydrotreated oil contains a suspended catalyst on which a large amount of metals are deposited, but such immobilized metals or suspended catalyst are substantially not covered by the catalytic cracking catalyst. Approved to be non-toxic.

The amount of soluble metals in the oil supplied to the catalytic cracking process is preferably as small as possible, but usually 5011 as the amount equivalent to vanadium.
1) Hydrogenation is performed so that the concentration is less than m, preferably less than lQppm.

Here, the vanadium equivalent amount is converted into vanadium content with one unit being the amount at which the poisoning effect of the supplied oil is the same as that of vanadium, and the vanadium and nickel content in the supplied oil is [■ ] and [Ni), it is usually expressed by the following equation.

[■] Equivalent amount = [V] + 4 (Ni) The catalytic cracking step in the present invention can be carried out in a conventional manner, for example, any method such as fixed bed, fluidized bed, moving bed, suspended bed, etc. can be adopted. However, in the case of the present invention, it is preferable to use a fluidized bed method in which the powdered catalyst is dispersed in oil.

The details below will focus on this method, but of course, the basic matters for catalytic cracking reactions, such as the catalytic cracking mechanism, catalyst regeneration, and reaction conditions, also apply to other reaction methods. be.

The treated oil containing suspended catalyst from the hydrotreating process is mixed with the finely powdered catalytic cracking catalyst recycled from the regeneration process and sent to the catalytic cracking process.

Although the mixing ratio of the catalytic cracking catalyst and the feed oil can be changed arbitrarily, it is usually determined depending on the reaction conditions of the catalytic cracking and the properties of the residual carbon content in the feed oil.

In the catalytic cracking process, the residual carbon content in the supplied oil is reduced to 1.
Although about 2 to 2.0 times more coke is deposited on the catalyst, in order to maintain the activity and selectivity of the catalyst, it is desirable to reduce the rate of coke deposition on the catalyst by at most a few points.

Therefore, when the residual carbon content of the feed oil is large, it is usually preferable that the weight ratio of the catalytic cracking catalyst to the feed oil is 5 or more.

The ratio of the suspended catalyst in the feed oil to the catalytic cracking catalyst is in the range of 2 x 10-2 to 5 x 10' by volume, and usually about 2 x 10-3 to 5 x 10'.

Therefore, the equipment such as a reaction column used in the catalytic cracking step in the method of the present invention, the applied reaction method, and reaction conditions may be in accordance with conventional methods, and the reaction conditions are 430 to 530°C, preferably 460 to 510°C, space velocity. 2 to 201/Hr.

The cracked products obtained in the catalytic cracking step are separated into a catalyst component consisting of a hydrotreating catalyst containing precipitated coke and a catalytic cracking catalyst, and cracked oil and gas.

The cracked oil gas is sent to a rectification step, where it is separated and recovered into gas, gasoline fraction, light gas oil fraction, heavy gas oil fraction, and cracked residue (bottom oil).

Among these, the heavy gas oil fraction may be recycled to the catalytic cracking step.

The catalyst mixture is sent to a catalyst oxidation regeneration step, and the regenerated catalyst is recycled to the catalytic cracking step.

The entire amount of soluble metals remaining in the oil supplied to the catalytic cracking process is deposited on the catalytic cracking catalyst and poisons the catalytic cracking catalyst.

As the amount of deposited metal on the catalyst increases, the coke and gas yield increases and the light oil yield decreases, so the vanadium equivalent metal content in the catalytic cracking catalyst is 5000111)11
It is desirable to keep the amount below, preferably 3000 pl)Ill or less.

This is accomplished by withdrawing a portion of the circulating catalyst and replacing it with fresh catalyst.

In the catalytic cracking process, the suspended catalysts contained in the feed oil are aggregated and coked with each other or with a large excess of the catalytic cracking catalyst, and sent as a catalyst mixture to the catalyst regeneration process.

In the method of the present invention, before circulating the regenerated catalytic cracking catalyst to the catalytic cracking process, the accompanying suspended catalyst may be separated and recovered, and the recovered suspended catalyst may be recycled to the hydrotreating process.

In order to facilitate the separate recovery of these two types of catalysts, the suspension catalyst and the catalytic cracking catalyst, it is convenient to set the particle diameters of these catalysts to different ranges.

The catalytic cracking catalyst is used in large excess compared to the suspended catalyst, the particle size of the catalyst is preferably large to some extent in order to fluidize and recover the catalytic cracking catalyst, and the suspension catalyst is difficult to fluidize and react. The volume average particle diameter of the catalytic cracking catalyst is 30 to 200 μm, preferably 40 to 100 μm, while that of the suspended catalyst is 30 μm, for reasons such as the fact that finer particles are preferable in order to avoid precipitation in the tower and transport pipes. Hereinafter, it is desirable to keep the thickness preferably below 20μ.

The diameter of the suspended catalyst is determined by taking into consideration the method of separate recovery and the recovery rate.

When the suspended catalyst is separated and recovered from the catalytic cracking catalyst and recycled for use in the first stage hydrotreating process, most of the metals in the raw heavy oil will precipitate on the suspended catalyst in the hydrotreating process. Therefore, a large amount of metals such as vanadium and nickel gradually adhere to the suspended catalyst during continuous operation.

It is known that in the normal heavy oil hydrotreating process, the catalyst deteriorates due to the accumulation of large amounts of metals, but in the hydrotreating process of the method of the present invention, the accumulation of metals on the suspended catalyst Even when the amount of metal increased, not only was there no substantial decrease in suspended catalyst activity, but in some cases the activity was even improved.

It has been found that suspension catalysts containing small amounts of vanadium or nickel have high activity as suspended catalysts used in hydrogenation processes, and solid fine powders containing no catalytic metals at all can be used as catalysts in hydrogenation processes. Even when used, it is recognized that a considerable portion of vanadium, nickel, etc. in the raw material heavy oil precipitates on this solid fine powder and becomes gradually activated during cyclic use.

Therefore, only carriers containing no catalytic metals can be used as suspended catalysts.

However, as a result of detailed studies, it has been found that suspension catalysts consisting only of carriers are particularly insufficient in deflow and denitrification activities, and in order to improve this, it is better to support catalytic metals.

These metals are preferably one or more metals selected from group Ⅰ, group Vla, and iron group of the periodic table, and the amount supported on the carrier is 0.2 as an oxide. Weight ratio or higher, preferably 1.0% to 50% by weight
It's heavy.

In particular (1) vanadium and/or molybdenum; and (2)
Catalysts that support two or more metals consisting of nickel and/or cobalt are preferred, and particularly catalysts in which the atomization ratio of component (2) to component (1) is 0.2 to 0.8 are preferred. Shows activity.

In special cases, fine carbon powder such as coke may be used as a suspension catalyst.

In addition, by allowing the rectification residue (bottom oil) obtained in the cracked oil rectification process of the present invention to stand still in a separation zone, preferably a standing tank, it is possible to remove the residue containing a small amount of catalyst fine powder caused by wear of the catalytic cracking catalyst. A clear liquid (decanted oil) is obtained, which may be recycled to the hydrotreating step and the fine catalyst powder used as part of the suspended catalyst.

Furthermore, in conventional catalytic cracking methods, the pulverized waste catalyst or the waste catalyst extracted to keep the amount of poisoned metals in the catalyst below a certain level was discarded, but in the method of the present invention, These can also be used as suspension catalysts in the hydrogenation process, either as they are or after being pulverized and carrying metals as required.

This is one of the major advantages of the method of the invention.

When circulating or reusing a suspended catalyst, its properties and composition may differ significantly from those of a newly supplied catalyst due to the adhesion of vanadium, nickel, etc. as described above, but this does not occur during hydroprocessing. This will not be a major hindrance to the process.

Alternatively, a new catalyst that is completely different from the suspension catalyst used initially may be supplied.

The carrier for the suspended catalyst is not particularly limited, but from the viewpoint of desulfurization activity, etc., the carrier should have a specific surface area of at least 50 m2/! i' is preferably alumina or alumina-silica.

In this case, as the alumina silica, a spent catalyst containing alumina silica extracted from the catalytic cracking process as described above can be used.

The catalytic cracking catalyst is preferably one that is highly active, less susceptible to poisoning effects due to precipitation of metals, and less likely to be sintered in the regeneration step.

Such a catalyst includes 5 to 20 weight lfi of X-type or Y-type zeolite in which sodium ions have been exchanged with pronto and/or rare earth ions, and 10 to 3 weight lfi of the remaining components.
A fine powder of a porous amorphous silica alumina matrix in which 0% by weight is alumina is mentioned.

The catalytic cracking catalyst is preferably spherical, with a volume average particle diameter of 30 to 200 μm, particularly 40 to 100 μm, as described above, for ease of oxidation regeneration, recovery, and circulation.
μ is preferable.

As mentioned above, the catalyst components in the catalytic cracking process are separated from the cracked oil and gas and sent to the catalytic oxidation and regeneration process.

However, a part of the catalyst gets mixed into the cracked oil gas and is sent to the rectification process, where the entire amount is finally collected in the cracked residue.

This decomposition residue is typically sent to a static tank where it is separated into a supernatant liquid with a low solids content and a lower phase containing most of the unrecovered catalyst.

The lower layer can be returned to the catalytic cracking step, while the supernatant liquid (decanted oil) may be recycled to the hydrotreating step as described above.

Adoption of these circulation steps is advantageous in terms of lowering the yield of cracked residue, which is difficult to utilize effectively, and in terms of effectively utilizing the fine powder catalyst in the decant oil as a suspended catalyst.

Catalyst components containing coke deposited in the catalytic cracking step are sent to a catalyst regeneration step where they are oxidized and roasted at a temperature of 600 to 800° C. and regenerated.

The catalyst component from the catalytic cracking step is a mixture of catalytic cracking catalyst and trace amounts of suspended catalyst from the hydrotreating step;
As the method and apparatus for regenerating this catalyst mixture, known methods can be used as appropriate.

However, if the residual carbon content in the oil supplied to the catalytic cracking process is high, the coke yield in the cracking process will increase, making it easier for the catalyst regeneration tower to overheat, further increasing the recovery rate beyond that required in the catalytic cracking process. Steam will be obtained.

Therefore, in order to prevent overheating of the regeneration tower and at the same time recover excess steam as high-pressure steam, it is preferable to install a pipe for overheating prevention and high-pressure steam recovery in the regeneration tower.

The catalyst component subjected to the oxidative roasting treatment is usually separated from the roasting waste gas by a gas-solid separator, such as a one-stage or two-stage cyclone, provided in the regeneration tower.

Since the suspended catalyst contained in the separated catalyst component consists of a finer powder than the catalytic cracking catalyst, it is hardly recovered by the cyclone inside the regeneration tower and is discharged out of the regeneration tower along with the waste gas. .

The discharged suspended catalyst may be collected or recovered by any known method.

For example, when the concentration of sulfur oxides in the exhaust gas from a regeneration tower is regulated, a wet desulfurization treatment may be performed, and most of the suspended catalyst is collected during such an exhaust gas treatment step.

Alternatively, the suspended catalyst can be recovered by flowing the torrefaction waste gas containing the suspended catalyst into a recovery device, preferably a cyclone and/or an electrostatic precipitator.

In addition, collection and recovery can also be carried out by arbitrarily combining methods such as a mouth-face dust collection method, a packed bed dust collection method, and a cleaning dust collection method.

The regenerated catalytic cracking catalyst recovered by the gas-solid separator is recycled to the catalytic cracking process.

On the other hand, the recovered suspended catalyst may be disposed of as is, or may be recycled to the hydrotreating process.

Although this recovered suspended catalyst is mixed with a finely divided catalytic cracking catalyst, it is not necessary to separate it because it exhibits sufficiently high activity as a catalyst in the hydrotreating process.

Water or oil may be added to prevent the catalyst from scattering in the suspended catalyst recovery process, but these anti-scattering liquids may be supplied to the hydrotreating process without being separated.

The recovered suspended catalyst may also be subjected to metal recovery treatment by a known method to recover the metals contained therein, and then supplied to the hydrogenation process.

If the suspended catalyst becomes finer or coarser during circulation and reuse, making it difficult to separate and recover, adjust the particle size of part or all of the recovered catalyst using a known method.
Only those within a preferable range may be used cyclically.

The method of the invention will be explained in more detail with reference to the accompanying drawings, but the invention is not limited to the following embodiments.

Figure 1 shows a heavy duty system in which the produced oil obtained by the hydrotreating process of the present invention is supplied as it is to the catalytic cracking process, and the catalytic cracking catalyst and suspended catalyst are separated and recovered in the catalyst regeneration process and the separation process, respectively, and circulated. This is a flow sheet of a method for decomposing quality oil.

This method is particularly suitable for obtaining mainly gasoline fractions from metal-rich heavy oils.

In this figure, the feedstock heavy oil is hydrogen and cyclone 7,
Together with the regenerated recovery catalyst that is circulated from the electrostatic precipitator 7' through line 8, it is supplied through line 20 to the hydrotreating reactor 1, where it is treated at high temperature and under high hydrogen pressure.

The resulting product is discharged through line 21 to gas-liquid separator 2 where it is separated into treated oil and gas products.

The gas product is extracted through the line 22 and separated into hydrogen, hydrogen sulfide, light hydrocarbon gas, etc. in the circulating gas treatment device 3, and the hydrogen is recycled through the line 24.

Processed oil containing suspended catalyst is extracted from line 23, regenerated and recovered in diluted steam from the lower part of riser 4 and catalyst regeneration tower 6, and sent to the reaction tower together with a large excess of catalytic cracking catalyst that is circulated through line 25. 5.

A cyclone is formed inside the reaction tower 5, and the feedstock undergoes catalytic cracking in the riser 4 and the reaction tower 5, where it is separated into gas and solid into cracked oil gas and coke-adhered catalyst components.

The catalyst components are sent to the catalyst regeneration tower 6 through the communication pipe 26, and along the way, cracked oil adhering to or adsorbed on the catalyst components is steam stripped.

Air is blown into the regeneration tower 6 from the lower part thereof, where the coked catalyst mixture is oxidized and roasted in a fluidized state and regenerated.

A cyclone is formed inside the regeneration tower 6, and most of the regenerated catalytic cracking catalyst is separated here, extracted from the lower part of the regeneration tower 6, and circulated to the riser 4 through a line 25.

Most of the regenerated suspended catalyst is extracted from the upper part of the regeneration tower 6 along with the torrefaction waste gas through a line 27 and sent to the cyclone 7 and the electrostatic precipitator 7'.

The suspended catalyst recovered here is circulated to the hydrotreating reactor 1 via line 8.

The cracked oil gas separated in the reaction column 5 flows through a line 28 to the rectification column 9 and is separated into respective fractions and cracked residues.

The residual oil is sent to a stationary tank 11 via a line 10, and the sediment layer containing a large amount of fine powder catalyst is circulated to the riser 4 via a line 12 along with a portion of the heavy gas oil fraction returned via a line 29. be done.

The supernatant liquid in the stationary tank 11 is recovered as decant oil.

Figure 2 includes a step of separating the hydrotreated oil into light components and heavy components, circulating part of the heavy component to the hydrotreating step, and supplying the remainder to the catalytic cracking step for cracking treatment. This is a flow sheet of a heavy oil decomposition method.

This method is particularly suitable for obtaining high-quality naphtha and kerosene from heavy oil containing many metals.

In FIG. 2, the constituent parts indicated by 101 to 112, 120 to 122, and 124 to 129 are 1 to 12 in FIG.
．． 20 to 22 and 24 to 29, respectively, and are functionally the same.

The treated oil that leaves the hydrogenation reaction tower 101 and is separated from gas components by the gas-liquid separator 102 is supplied to the distillation tower 113, where it is separated into fractions such as naphtha, kerosene, and heavy oil, and bottom oil. Ru.

A portion of the bottom oil containing suspended catalyst is routed to lines 114 and 115.
The remainder of the bottom oil is circulated through lines 114 and 116 to lines 117 and 11.
It is sent to riser 104 through line 119 along with a portion of the kerosene fraction and the heavy oil fraction sent through line 119 .

This feed oil undergoes catalytic cracking in the riser 104 and the catalytic cracking reaction tower 105, and is separated into cracked oil gas and a catalyst mixture.

The obtained cracked oil gas is extracted through line 128,
In the rectification column 109, it is separated and recovered into various fractions such as a gasoline fraction.

Meanwhile, the catalyst mixture is regenerated, separated, and recovered by a process similar to that described with respect to FIG.
04, the suspended catalyst is recovered by a cyclone 107 and an electrostatic precipitator 101', and is recycled to the hydrotreating reaction column 101 via line 108.

Although the method of the present invention is preferably carried out continuously, it can of course also be carried out in a batch system or a semi-batch system.

The heavy oil decomposition method of the present invention has the following advantages.

(1) Since deterioration of the suspended catalyst can be ignored in the hydrotreating process and treated oil with constant properties can be supplied to the catalytic cracking process for a long period of time, light oil with stable properties can be obtained at a constant yield.

(2) Good quality light oil can be obtained in high yield by combining hydrotreating and catalytic cracking.

(3) The process is simplified because the suspended catalyst recovery process also serves as the pulverized catalyst recovery process in the catalytic cracking process.

(4) Flexible hydrogenation treatment depending on the properties of the raw material heavy oil can be easily performed, and light oil with stable properties can be obtained at a relatively constant yield regardless of the properties of the raw material.

(5) Since the suspended catalyst does not substantially deteriorate during cyclic use, and is replenished by pulverization of the catalytic cracking catalyst, the amount of catalyst consumed is significantly lower than in conventional methods.

(6) Although the decomposition rate in the hydrotreating process is high, the amount of chemical hydrogen consumed is low.

(7) The middle distillate separated from the hydrotreated oil has a small amount of aromatic components, so it can be used as a high-quality kerosene raw material.

(8) Since the metal removal rate and residual carbon reduction rate in the hydrotreating process are large, light oil can be obtained in high yield from heavy oil containing a large amount of these metals with extremely low catalyst consumption.

(9) During cyclic use, the amount of metals deposited on the catalytic cracking catalyst is small, so the activity of the catalytic cracking catalyst decreases very little.

Next, the present invention will be explained by examples.

In this example, concentrations or proportions are expressed on a weight basis unless otherwise specified.

Example Heavy Oil An atmospheric distillation residue having the following component content was used as a heavy oil raw material.

Sulfur 2.90 Nitrogen 0.16% Vanadium 29p11M+1 Nickel
8゜4pplIl iron
2.0p Conradson Carbon 8.33 Good Ash Content 0.08 Good Suspension Catalyst Specific Surface Area 230 m2/9, Pore Volume 0.52 cc
/ fi 80 parts of commercially available γ-alumina and a specific surface area of 4
40 m2/g, pore volume 0.65 cc/,! i
20 parts of a silica-based catalytic cracking catalyst containing Y-type zeolite exchanged with rare earth ions,
2 vanadium and nickel each by a known method.
．． It was made to carry so that it might be 4% and 1.2%.

To this catalyst, 10 parts of kerosene was added and the mixture was pulverized using a ball mill.

From this mixture of finely powdered catalyst and kerosene, most of the kerosene was removed by vacuum distillation to obtain a suspended catalyst paste.

Formation of Suspended Layer The above catalyst paste was added to the above heavy oil raw material so that the catalyst concentration was 5.0%, and mixed by vigorous stirring at about 80°C.

The resulting suspension mixture was allowed to stand at 80° C. for about 10 hours, and the upper suspension layer was used in the following reaction.

Incidentally, almost no catalyst precipitate was observed at the bottom of the stationary tank.

The upper suspension layer was passed through a 0.2μ filter and the particle diameter of the residue was examined, and the volume average particle diameter was approximately 3μ.
Met.

As a hydrogenation treatment hydrogenation reactor, the inner diameter is 15fi and the decoration part length is 35mm.
The suspended layer was hydrogenated using a conventional high-pressure flow reactor equipped with a reaction tube having a thermocouple protection tube in the center of the 0R.

The reaction conditions are as follows.

Hydrogen pressure 100 to 5'/7 Liquid hourly space velocity 1.01/Hr Reaction temperature
450°C Hydrogen/untreated oil ratio 1,500 1/11 Hydrotreated oil The composition of the hydrotreated oil obtained by the above hydrogenation treatment was as follows.

Moreover, the chemical hydrogen consumption amount was about 14013/l.

01 to 021.4 03 to 044.0% C6 to 350°C 38,6 to 350 to 550°C 38.5 550°C (including catalyst) 16.5 In addition, the above hydrogenation treatment is continued When the inside of the reaction tube was inspected after 50 hours, no signs of coking were observed.

This indicates that coking is less likely to occur in the hydrotreating step of the method of the present invention, even though the decomposition rate is extremely high.

Oil supplied to the catalytic cracking process Among the above hydrotreated oils, components heavier than C5 were subjected to catalytic cracking without removing the remaining suspended catalyst.

When the heavy components were passed through a 1μ filter to separate the catalyst, the amount of separated solids was found to be 6.8%.

The results of analyzing this 0 liquid are shown below.

Sulfur 0.25% Nitrogen 0.12% Vanadium 0.61) I) III Nickel
0.3 pl) I11 iron
0.1 p voice Conradson carbon 3.5 high ash content 0.1 ridge catalytic cracking As the catalytic cracking catalyst, the powdered zeolite-containing silica alumina catalyst used as part of the raw material for the suspension catalyst was used with a diameter of 3 cm and a thickness of 3 cm. Compression molded pellets of approximately 2 wl1 were used.

Catalytic cracking was carried out using a conventional fixed bed atmospheric pressure flow reactor.

The reaction conditions are as follows.

Reaction temperature 480°C Liquid hourly space velocity 2.01/Hr Continuous reaction time 2. Regeneration and separation of OHr catalyst After completion of the catalytic cracking reaction, residual cracked oil and gas were sufficiently purged by passing helium gas through the catalyst layer in reaction source i, and then passing through a mixed gas with a helium:air ratio of 5=1 at 700°C. Oxidized and roasted.

Most of the suspended catalyst adhered to the catalytic cracking catalyst during catalytic cracking, and some of it was discharged along with the torrefaction exhaust gas, so the torrefaction exhaust gas was led to a simple electrostatic precipitator and collected.

However, a considerable portion of the suspended catalyst deposited on the catalytic cracking catalyst did not come off during oxidative roasting, so it was removed and recovered by passing helium gas through the catalyst layer while vibrating the catalyst layer after oxidizing roasting.

The yield of the suspended catalyst thus recovered was 3.2 times more than the feed oil to the catalytic cracking.

Furthermore, analysis results for carbon remaining in the recovered suspended catalyst were hardly observed.

The catalytic cracking catalyst and suspended catalyst thus regenerated, separated, and recovered were reused as shown below.

The amount of coke deposited on the catalyst due to catalytic cracking was determined by analyzing the roasted waste gas, and it was found to be 28% of the supplied oil, including the coke content in the recovered suspended catalyst.

decomposition oil The cracked oil produced by catalytic cracking was rectified.

The yield of each fraction obtained relative to the oil fed to the catalytic cracking was as follows.

01~C2 03~C4 C5~<2000G 200~350℃ 350~550℃ 550'C≧ Reuse of suspended catalyst The quality oil raw material was subjected to hydrogenation treatment, catalytic cracking, and regeneration recovery in sequence under the same reaction conditions and reaction method as above, and the same process was repeated with one more modification.

As a result, results were obtained that were almost the same as the results of the initial hydrogenation treatment.

Reuse of catalytic cracking catalyst Using the regenerated catalytic cracking catalyst obtained as above,
The above operation of catalytically cracking the feed oil for 2 hours and regenerating the catalyst was repeated four more times.

In either case, almost the same results as the initial catalytic cracking treatment results were obtained.

An analysis of the amount of vanadium contained in the 5th regenerated catalytic cracking catalyst counting from the first operation revealed that it was approximately 30 pplIl.
Met.

Therefore, deterioration of the catalyst due to deposited metals is almost ignored.3.
6% 8.1 buns 43.9 units 16.0 units 11.7% It is recognized that 5.7 ton can be made.

In addition, when hydrotreating was carried out using the recycled and recovered suspension catalyst, and the resulting feed oil was catalytically cracked using the first regenerated catalytic cracking catalyst, the results were almost the same as the first catalytic cracking results. there were.

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing one embodiment of the method of the present invention, and FIG. 2 is a flow sheet showing another embodiment of the method of the present invention. In the figure, dotted arrows indicate circulation lines. 1゜102...Hydrogenation reactor, 2,102...
... Gas-liquid separator, 3,103 ... Circulating waste treatment device, 4゜104 ... Riser, 5,10
5... Catalytic reaction tower, 6.106... Catalyst regeneration tower, 7,107... Cyclone, 7',
107'... Electrostatic precipitator, 8,108...
...Suspended catalyst circulation line, 9,109...Rectification column, 10.110...Residue oil transport line, 11
, 111... Static tank, 12, 112...
・Precipitation lower layer circulation line, 113... Distillation column, 1
14... Bottom oil transport line, 115...
- Tower bottom oil circulation line, 116... Tower bottom oil supply line, 117... Kerosene and light oil circulation line, 118.
...Distillate supply line, 119...Processed oil supply line.

Claims (1)

[Claims] 1. A fine solid particulate hydrotreating catalyst is suspended in heavy oil at a hydrogen pressure of 10-350 Kf/CrA and a temperature of 420-350 Kf/CrA.
A hydrotreating step in which the hydrotreating is carried out at 470°C, and the treated oil in which the hydrotreating catalyst obtained in the hydrotreating step is suspended,
A method for cracking heavy oil, comprising a catalytic cracking step of carrying out catalytic cracking at a temperature of 430 to 530°C in the presence of a cracking catalyst. 2. Gas-liquid separation of the hydrogenation product of the hydrogenation process,
2. The method of claim 1, wherein the liquid phase portion containing the hydrotreating catalyst is fed to a catalytic cracking step. 3. Gas-liquid separation of the hydrogenation product of the hydrogenation process,
The obtained liquid phase portion containing the hydrogenation catalyst is distilled to separate it into a distillate component not containing the hydrotreating catalyst and a bottom component containing the hydrotreating catalyst, and the bottom component is supplied to the catalytic cracking process. The method according to claim 1 or 2. 4. The method according to claim 3, wherein a part of the bottom component is recycled to the hydrotreating step. 5. The method according to claim 3 or 4, in which the heavy portion of the distillate component is fed to the catalytic cracking step together with the bottom component. 6. The method according to any one of claims 3 to 5, wherein the light portion in the output component is fed to the catalytic cracking step together with the bottom component. 1. Any one of claims 1 to 6, in which the cracked oil obtained in the catalytic cracking step is subjected to distillation treatment and separated into a fraction lighter than heavy gas oil, a heavy gas oil fraction, and bottom oil. That method. 8. The method of claim 7, wherein at least a portion of the heavy gas oil fraction is recycled to the catalytic cracking step. 9. Claim 8, in which the column bottom oil is allowed to stand still and separated into a precipitated lower layer and an upper layer supernatant, and the lower layer and the upper layer are recycled to the catalytic cracking step.
Section method. 10. The method according to claim 8 or 9, wherein the upper supernatant liquid is recycled to the hydrogenation process. 11. The method according to any one of claims 1 to 10, wherein the hydrotreating catalyst has a volume average particle diameter of 30 μm or less. 12 Hydrotreating catalyst contains at least one kind selected from Group V, Group VIa and Iron group of the periodic table as an oxide.
．． Claims 1 to 1 containing 2 to 50 weight percent
Either method in Section 1. 13 Hydrotreating catalyst contains at least one metal (4) selected from vanadium and molybdenum, and at least one metal (B) selected from nickel and cobalt.
), and the atomic ratio of metal (B) to metal (4) is 0.2 to 0.8.
Either way. 14. The method according to claim 12 or 13, wherein the hydrotreating catalyst carrier is alumina and/or alumina silica having a specific surface area of 50 m2/g or more. 15. The method according to any one of claims 1 to 13, wherein the hydrotreating catalyst is a finely divided waste catalytic cracking catalyst. 16. The method according to any one of claims 1 to 15, wherein the hydrotreated product in the heavy oil in the hydrotreating step is changed to a product with a weight content of 0.2 to 20. 17. The method according to any one of claims 1 to 16, wherein the hydrogenation treatment is carried out so as to reduce the amount of soluble metals in the treated oil to 5 Qppm or less in terms of vanadium equivalent. 18 The volume average particle diameter of the catalytic cracking catalyst is 30 to 300μ
The method according to any one of claims 1 to 17. 19. The method according to any one of claims 1 to 18, wherein the catalytic cracking catalyst is porous silica alumina containing 3 to 20 by weight of proton and/or rare earth exchange type zeolite. 20. The method according to any one of claims 1 to 19, wherein the metal content of the catalytic cracking catalyst in the catalytic cracking step is maintained at 5000 ppI11 or less as vanadium equivalent. 21 A patent claim in which the catalyst component separated from the cracked product of the catalytic cracking process is regenerated by oxidative roasting, and then separated into a catalytic cracking catalyst and a hydrotreating catalyst according to their particle sizes, and each is reused. The method according to any one of the ranges 1 to 20.