JPH0237389B2 - ITSURYUGATAKOATSUEKISOSUISOKATOKOATSUKISOSUISOKATONOCHOKURETSUKOTEINYORISOJUSHITSUYUKARAKEISHITSUYUOSEIZOSURUHOHO - Google Patents

Description

[Detailed Description of the Invention] Purpose The present invention is a method for producing light oil such as kerosene, jet fuel, gasoline, etc. from crude heavy oil. 2. A medium fraction is generated, which is then subjected to high temperature, high pressure catalytic hydrogenation in the gas phase to further refine and lighten it.
This paper relates to improvements in the stage hydrogenation process.

Here, crude heavy oil is a general term that includes petroleum-based distillation residual oil, shale crude oil, sand oil, low-temperature tar, coal liquefied heavy oil, etc., and has an initial boiling point of approximately 330 at normal pressure. Refers to crude oil consisting mainly of high boiling point fractions above ℃.

In recent years, as the price of crude oil has soared and its resource limitations have been recognized, raw materials for producing hydrocarbons have been diversified, with crude shale oil, sand oil, low-temperature tar, etc. gaining attention. . However, all of these oils are heavy, and many of the newly developed oil fields are also heavy, so there is an overall tendency for feedstock oil to become heavier. On the other hand, for heat sources such as steel and thermal power generation, which were the main uses of heavy oil in the past, a switch to and use of alternative energies such as coal is underway. For this reason, demand for liquid fuels as a whole is trending towards lighter fuels, creating a qualitative imbalance between supply and demand. For this reason, technology to lighten crude and heavy oil has recently become increasingly important.

However, the above-mentioned crude heavy oil contains impurities such as polar polymer compounds such as asphaltene and bityumene, which contain heteroatoms such as oxygen, sulfur, and nitrogen, although the degree varies depending on the type and production area. It may also include a polymeric organic complex compound containing a metal atom such as vanadium. A reaction in which heteroatoms and metal atoms are removed by catalytic hydrorefining (inevitably accompanied by lightening/mediumization), and a catalytic hydrogenolysis of carbon-carbon bonds in polymeric hydrocarbon chains and/or rings. If the reaction of lightening and lightening could be carried out continuously, there would be no need for two independent plants: a hydrogenation plant for crude heavy oil and a hydrogenation plant for the produced crude, light and medium oil. Since this can be done with a plant, it can have an extremely large economic effect.

Prior art The technology for modifying and removing the above-mentioned polymer impurities from crude heavy oil was initially developed to produce low-sulfur heavy oil by hydrorefining high-sulfur crude heavy oil as a pollution control measure. When carrying out catalytic hydrogenation treatment of heavy oil in the liquid phase, the hydrogenation catalyst can be used in fixed bed, floating bed (e.g. Japanese Patent Publication No. 42-26105: H-oil method), stationary bed (e.g. Japanese Patent Publication No. 47-4627 and Japanese Patent Publication No. 47-1986: H-oil method). ―6219
A method has been proposed for use in the Institute of Technology Law). However, the purpose of these methods is to hydrogenate and deflow only highly reactive sulfur-containing polymer compounds, and use the hydrogenated oil as a product as it is. Therefore, this method uses a shaped or coarse-grained catalyst in which a hydrogenation active component is supported on a carrier under relatively mild reaction conditions. Nevertheless, in practice there are various problems with regard to catalyst life and regeneration.

In general, if a shaped or coarse-grained catalyst is used to advance liquid phase hydrogenation to a high degree, asphaltenes or bityumens in crude heavy oil are first preferentially adsorbed on the outer surface of the shaped or coarse-grained catalyst, and then thermally decomposed.・Polycondensation occurs to produce a polymeric polycyclic aromatic structure, so-called free carbon, which coats the catalyst surface and obstructs the performance of the catalyst. In other words, when attempting to liquid-phase hydrogenate coarse heavy oils other than paraffin-based oils that contain only a small amount of soft sulphaltenes that are susceptible to hydrogenation, the use of shaped or coarse-grained catalysts with small exposed external surface areas will result in problems with the reaction operation format. Regardless of the circumstances, it is extremely difficult to maintain a catalyst life long enough to be industrially usable. In addition, nickel and
Sulfides of metals such as vanadium adhere to and coat the surface of the catalyst, but these also cause a decrease in the activity of the catalyst.

In general, catalysts that have deteriorated due to the adhesion of free carbon are
Through regeneration processing such as slow combustion in the presence of water vapor,
Its activity can be restored to some extent. However, in the case of a fixed bed reactor, the hydrogenation operation must be interrupted during the regeneration process, and if this is to be avoided, multiple reactors must be installed and a complicated switching system required for operation. Furthermore, even in the case of a floating bed or stationary bed reactor from which the catalyst can be extracted during operation, it is technically and economically burdensome to regenerate the large amount of extracted waste catalyst on an industrial scale. Furthermore, it is not easy to regenerate molded catalysts that have deteriorated due to adhesion of metal sulfides such as nickel and vanadium, and must be sent to a separate waste catalyst recovery plant.

As a means to solve the problems that occur during the liquid phase hydrogenation of crude and heavy oil using fixed beds, floating beds, and stationary beds, we developed a liquid phase suspension catalyst layer (hereinafter referred to as a suspension layer) in which a finely powdered hydrogenation catalyst is dispersed and suspended. (abbreviation)) may be used.

There are few precedents for the industrial use of suspension as a reaction phase, and there is only a high-temperature, high-pressure liquid-phase hydrogenation method that involves direct liquefaction of coal. In order to produce a light liquid fuel with a boiling point of approximately 200°C or less under normal pressure using this direct coal liquefaction method, first, coal powder/fine hydrogenation catalyst and heavy oil are used in a high-temperature, high-pressure liquid-phase hydrogenation plant. The mixture, so-called paste, is hydrogenated to produce primarily heavy oil (recycled for paste production) and crude light oil. This crude light oil is then passed through a separate high-temperature, high-pressure gas-phase hydrotreating plant to produce refined light oil, and finally, this refined light oil is passed through a separate high-temperature, high-pressure gas-phase hydrocracking plant to produce light fuel oil such as gasoline. It was hot. In other words, it is necessary to use three independent high-temperature, high-pressure hydrogenation plants in series, which is a major cause of the enormous construction costs of a coal liquefaction plant and the extremely high production cost of liquefied light fuel oil. At the end of the 1930s, at the South Manchuria Railway Co., Ltd. Central Research Laboratory, to which the present inventor belonged, a series-type coal liquefaction system was developed in which a liquid-phase hydrogenation cylinder and a gas-phase hydrogen cylinder were connected in series via a high-temperature separation cylinder. A method was devised, a series of small-scale industrial tests were carried out, and it attracted great attention. However, contrary to expectations, the molded catalyst inside the gas-phase hydrogenation cylinder gradually weakened and deactivated, and the research was discontinued.

After that, this concept remained unresolved for many years, but as a result of investigating the cause, the present inventor was able to clarify the reason.

First of all, even if carefully selected coking coal for liquefaction is used, 7~
Contains 10% inorganic matter. Since this remains together with the catalyst in the liquefied residue, it has been extremely difficult both technically and economically to recover and reuse the catalyst, as well as to dispose of the liquefied residue with the aim of recovering the oil content.
Therefore, disposable, inexpensive, but low-activity catalysts (all of which are iron sulfide or raw materials that produce iron sulfide) were used exclusively in each country. The above-mentioned serial type coal liquefaction industrialization test was no exception to this.

Therefore, the progress of hydrogenation in the first stage liquid phase hydrogenation cylinder is shallow, and therefore a large amount of heavy fraction oil vapor is carried by excess hydrogen to the second stage gas phase hydrogenation cylinder, It was determined that this resulted in the gradual attenuation of the entire hydrogenation catalyst.

As mentioned above, in recent years, emphasis has been placed on establishing a technology for producing light oil by catalytic hydrogenation of crude heavy oil. However, most of the technologies that have been proposed to date are liquid-phase catalytic hydrogenation, which was developed to obtain low-sulfur heavy oil as a pollution control measure, and jet fuel, which is based on gas-phase catalytic hydrogenation of medium oil, which has been established.・It is a simple combination of two independent hydrogenation methods: a method for producing light oil such as gasoline. At that time, catalyst beds such as fixed beds, floating beds, and stationary beds were used in the first liquid-phase catalytic hydrogenation methods, and suspended beds were hardly considered at all. The reasons for this result were, firstly, that the direct coal liquefaction method itself, which is the only industrialized example of a suspended bed, was extremely difficult to operate; and secondly, the suspension bed and vapor-formed hydrogen catalyst were very difficult to operate. The above-mentioned industrialization test in which packed beds (hereinafter referred to as packed beds) were connected in series could not achieve the expected results, and thirdly, the finely divided hydrogenation catalyst was suspended in the hydrogenation product. This is thought to be due to the general consensus that it is troublesome to separate the catalyst from the products in the process that involves it.

In JP-A-53-78203 and JP-A-54-40806, pulverized waste hydrodesulfurization catalyst is used as a powder catalyst, and a mixture of this, hydrocarbon, and hydrogen is
A method has been proposed in which the hydrocarbons are subjected to a reaction at a temperature of 480° C. and a pressure of 30 to 100 kg/cm ² G. However, these are methods whose main purpose is to obtain low-sulfur heavy oil by hydrorefining at a relatively low hydrogen pressure. At that time, the hydrogenated product is taken out in liquid form with the powdered catalyst mixed in.
This requires mechanical separation of the powdered catalyst from the total product. In order to further reduce the weight, it was necessary to distill the liquid product to extract the vapor of the light and medium oil fraction, condense it, and send it to a separate plant for gas-phase hydrogenation. .

Furthermore, JP-A-55-165993 describes a method of suspending a fine solid particulate hydrogenation catalyst in heavy oil and hydrotreating it; It is only used as a pre-treatment. As the main reaction is catalytic pyrolysis without hydrogen, it is impossible to suppress the generation of a large amount of free carbon. Therefore, it is necessary to regenerate the spent catalyst by oxidative roasting treatment, but in this respect, the conventional methods are not free from the drawbacks.

Structure of the Invention The present inventor is a raw material crude heavy oil (hereinafter abbreviated as raw material oil)
Focusing on the fact that the content of inorganic substances in coal is very small, we skillfully applied the knowledge we gained when we were involved in the industrialization test of the direct liquefaction method of coal to a method for producing light oil by high-temperature, high-pressure catalytic hydrogenation of feedstock oil. As a result, the present invention, which eliminates the drawbacks of the conventional method, has been completed. In other words, it is based on a process in which a liquid-phase hydrogenation cylinder having a suspended layer and a gas-phase hydrogenation cylinder having a packed bed are connected in series via a high-temperature separation cylinder.
This method has the technical and economical effect of extending the life of not only the liquid-phase hydrogenation catalyst but also the subsequent gas-phase molded hydrogenation catalyst.

Here, the term "series coupled processes" refers to
Coarse, light and medium fractions (boiling points under normal pressure are approximately
The vapor of crude, light and medium fractions and unreacted oil can be collected without going through the process of condensing the vapor of the fraction containing polar polymer compounds at temperatures below 330°C to obtain liquid crude, light and medium oil. After the generated gas stream mainly consisting of hydrogen (hereinafter referred to as the generated gas stream) is separated from the catalyst residual oil slurry in a high-temperature separation column, it can be used as it is, or the crude and heavy fraction entrained in the generated gas stream (the boiling point under normal pressure is approximately
By condensing and separating only the vapor (the fraction containing polar polymer compounds at temperatures above 330°C), the crude, light and medium fractions are sent as vapor together with hydrogen to the next connected gas-phase hydrogenation cylinder. It means the process of

(1) Basic structure and its characteristics In order to clarify the basic structure and overall process flow of the present invention, explanations will be given below with reference to the attached drawings, but the embodiments of the present invention are limited only to these. isn't it.

In FIG. 1, part A on the left side of the broken line is a part where normal pressure equipment is arranged, and part B on the right side of the broken line is a high pressure reaction zone. The high-pressure reaction zone consists of (a) a liquid-phase hydrogenation process of feedstock oil, (b) a high-temperature separation process of the product gas overflowing from the liquid-phase hydrogenation column and the catalyst-containing residual oil slurry,
(c) Gas-phase hydrogenation process of coarse light and medium fractions in the produced air stream, (d) Separation and recovery of produced oil and hydrogen circulation process,
It is roughly divided into five steps: (e) circulation step of catalyst residual oil slurry; The present invention is characterized by a comprehensive process that combines the above-mentioned steps, centering on the liquid-phase hydrogenation step (a) using this suspension layer, and brings about excellent effects as described below. Details of these will be explained below.

(a) Liquid-phase hydrogenation process for feedstock oil The liquid-phase hydrogenation process referred to here is a process in which a suspension layer is created in a liquid-phase hydrogenation cylinder, and feedstock oil and hydrogen are passed through this layer to lighten and neutralize the feedstock oil. This is the process of The feature of this process is that a catalyst-containing residual oil slurry (hereinafter abbreviated as "slurry") whose main component is unlightened heavy residual oil that overflows from the liquid-phase hydrogenation cylinder in a liquid state with finely powdered hydrogenation catalyst suspended in it is produced. After separating it from the produced gas stream in the next high-temperature separation column, it is circulated into the liquid-phase hydrogenation column, thereby converting almost all of the feedstock oil into vapor of coarse, light and medium fractions. .

The water content of the feedstock oil is first separated, and then the inorganic and
Thoroughly separate fine organic solids. After that, it is sent to the raw material supply tank 12 via the line 11, where the fine powder hydrogenation catalyst is dispersed and suspended, and then pressurized by the raw material pump 13, and the volume from the line 14 is approximately 10 ³ to 10 ⁴ in terms of room temperature and normal pressure. It is mixed with twice as much (circulated) high-pressure hydrogen, then heated to a temperature higher than the liquid phase hydrogenation reaction initiation temperature via a heat exchanger 15 and a preheater 16, and then continuously fed into the bottom of the liquid phase hydrogenation cylinder 17. . The reason why the catalyst and hydrogen are mixed from the beginning is to prevent the feedstock oil from undergoing thermal decomposition and polycondensation to generate free carbon during the preheating stage. During steady operation, the finely divided hydrogenation catalyst is extracted as a slurry from the bottom of the high-temperature separation column 18, and then passed through an air cooler 26.
Warm slurry storage tank 28/Normal pressure slurry storage tank 31
The raw material is circulated and supplied to the raw material supply tank 12 through. In addition, it is also possible to directly feed the hot slurry using the pump 27 or the hot slurry using the pump 29 to the liquid phase hydrogenation cylinder.

When supplying the catalyst to the reaction system for the first time, the finely divided hydrogenation catalyst and thermally stable heavy oil are thoroughly mixed in advance to produce catalyst heavy oil containing a thick suspension of the catalyst for starting operation. This is then fed into the raw material supply tank 12 through the line 34, where it is thoroughly mixed to be uniformly dispersed and suspended in the raw material oil. For this purpose, a stirrer is usually installed in the raw material supply tank. Fresh hydrogen at the start of operation and make-up hydrogen during steady operation are supplied from the high-pressure hydrogen line 25.

As the finely divided hydrogenation catalyst, any conventionally known finely divided catalyst having heavy oil hydrogenation activity can be used, but if the activity is particularly high, even expensive catalysts may be used, such as molybdenum disulfide or tungsten disulfide as the main component. The advantage is that it can be used either as a multicomponent catalyst or as a supported catalyst. As mentioned above, suspension beds were once used in the direct liquefaction method of coal, but coking coal for liquefaction usually contains 7 to 10% inorganic matter even after coal preparation, and this together with the catalyst remains in the liquefaction residue. Because of the accumulated residue, it becomes difficult to recover and reuse the catalyst, and in the end, we have no choice but to use disposable, inexpensive catalysts with low activity. On the other hand, in the case of crude heavy oil, the content of inorganic substances is very low, so that the used catalyst can be recycled and reused as in the present invention. Therefore, if the activity is high, even an expensive catalyst can be reused at a high concentration of several tens of percent, thereby significantly increasing the productivity and economic efficiency of high-pressure hydrogenation of feedstock oil.

The finer the particle size of the suspended finely divided hydrogenation catalyst, the wider the active area, and the better the stability of the suspended oil, so it is desirable that the particle size be in the micron range, for example.

As a method for producing such a fine powder catalyst, any known method can be used, such as a method of mixing precipitate with oil or a method of thermally decomposing an emulsion of an aqueous salt solution and oil. By being such a fine powder, the active surface area per weight of the catalyst is significantly increased, and the catalytic hydrogenation efficiency is increased.
Handling, such as pumping the slurry, is also facilitated. Generally, the optimal catalyst concentration is determined depending on the reactivity of the feedstock oil, and the appropriate catalyst concentration in the suspension layer is usually about 5 to 20% by volume.

The operating conditions of the liquid-phase hydrogenation cylinder, such as the amount of oil fed, the ratio of hydrogen to feedstock oil, the reaction pressure, and the reaction temperature, depend on the reactivity of the feedstock oil and the activity and activity of the catalyst.
It varies depending on the particle size, its suspended concentration, and the height of the suspended layer. In general, the liquid space velocity of feedstock is 1 to 5 hr ^-1 , the volume ratio of hydrogen to feedstock is approximately 10 ³ to 10 ⁴ when converted to normal temperature and pressure, the pressure is usually 130 to 300 atm, and the reaction temperature is approximately 370 to 440°C. It is. Since the temperature rises in the liquid-phase hydrogenation cylinder due to the heat of reaction, the feedstock oil and hydrogen are heated to a temperature slightly higher than the reaction starting temperature of approximately 350 to 390°C in the liquid-phase hydrogenation cylinder through the heat exchanger 15 and preheater 16. All you have to do is heat it up and send it in.

In the case of feedstock oils that have a small content of asphaltenes and bityumenes and are rich in components with a linear chemical structure, such as paraffin-based petroleum residues or shale crude oils, the reaction temperature that provides the desired reaction rate is required. and reaction pressure (hydrogen partial pressure) are both relatively low. For example 370-400
In some cases, the purpose can be fully achieved even at temperatures below ℃ and 200 atm. However, hard asphaltene-rich naphthene-based petroleum residues, polycyclic aromatic-rich shale crude oils, and low-temperature tars and
When using raw material oil such as coal liquefied heavy oil,
By increasing the reaction temperature and pressure slightly, for example,
It is desirable to maintain the temperature at 400-440℃ and at least 200 atm. In addition, in the case of feedstock oil rich in such high boiling point fractions, if a part of the medium fraction produced by the method of the present invention is mixed and diluted with it and used,
Increasing the solubility of hydrogen in the suspended layer leads to an effect similar to increasing the hydrogen partial pressure. In addition, since the concentration of asphaltene or bityumen in the suspended layer is reduced, it is advantageous for exerting the catalytic ability. At first glance, mixing and using produced medium oil may seem disadvantageous because it shortens the residence time of feedstock oil in the liquid phase hydrogenation cylinder, but in reality it is technically and economically disadvantageous. It is often advantageous.

In the suspension tank, most of the heteroatoms of the polar polymer compounds in the feed oil and the metal atoms in the polymer organic complex compounds are hydrogenated, and oxygen is converted to water, sulfur to hydrogen sulfide, nitrogen to ammonia, and The metal further reacts with hydrogen sulfide to form a sulfide, both of which are separated from the hydrocarbon ring or chain. At this time, the molecular weight decreases due to the removal of these heteroatoms and metal atoms, but some of the actual hydrocarbon components are also hydrogenolyzed and become light and medium, and at the same time, hydrocarbon gases such as methane, ethane, and propane are produced. A small amount of by-product is produced. Here, it is not necessary to lighten or mediumize all of the feedstock oil in one pass, but rather a portion of it, approximately 30 to 70
% should be reduced to light/medium. Then, the remaining heavy residual oil is separated into gas and liquid from the generated air stream as a slurry together with a finely divided hydrogenation catalyst in the next high-temperature separation column 18, and is then recirculated and sent to the liquid-phase hydrogenation column for reuse (described later). Step (b) and (e) of
process).

The temperature of the liquid phase hydrogenation cylinder is basically adjusted by the preheating temperature of the feedstock oil and the amount of circulating hydrogen.
However, once the temperature exceeds the limit and begins to rise, the hydrogenation reaction is accelerated and more reaction heat is generated, causing the temperature to rise rapidly and run out of control. Therefore, a part of the circulating slurry is extracted in advance, cooled and stored in a storage tank 28 equipped with a cooler, and pumped 29 as needed.
By feeding it into the liquid phase hydrogenation cylinder, it is useful for temperature adjustment. Furthermore, if an emergency is required, by fractionating the produced oil according to the present invention and feeding an appropriate amount of the stored light/medium oil into the liquid phase hydrogenation cylinder, the reaction temperature can be easily raised by the heat of evaporation. can be controlled.

The method of the present invention allows the use of much higher catalyst concentrations than conventional methods using fixed beds, floating beds, stationary beds, etc. As a result, while maintaining a high hydrogenation rate, it is possible to operate at a reaction temperature lower, for example, by 20 to 40°C, than in conventional methods. Therefore, the content of crude heavy fraction vapor contained in the generated gas stream flowing out from the upper part of the liquid phase hydrogenation column can be kept lower than in the conventional method. As a result, combined with the separation effect of the crude and heavy distillate vapor by the internal mechanism of the high-temperature separation column, which will be explained later, the crude and heavy distillate vapor entrained in the product air stream sent to the next gas-phase hydrogenation column is The content is significantly lower, as a result of which the lifetime of the gas phase hydrogenation catalyst is greatly extended.

(b) High-temperature separation process of product airflow and slurry After the liquid-phase hydrogenation reaction, a product airflow and slurry are generated, so these are continuously overflowed from the top of the liquid-phase hydrogenation column to the next high-temperature separation column 18. send to Here, the overflow from the liquid phase hydrogenation cylinder is separated into a product stream and a slurry.
The high-temperature separation cylinder used has a normal gas-liquid separation function. A slurry storage section is provided at the bottom of the high-temperature separation cylinder, and a mist collector (not shown) is provided at the generated air outlet.

(c) Gas-phase hydrogenation process for coarse, light, and medium fractions Hydrogenation of coarse, light, and medium fractions is performed in a gas-phase hydrogenation cylinder with a packed bed. Although known equipment and catalysts may be used, this process is characterized by separating the generated gas stream from the slurry in a high-temperature separation column, and then feeding it as a gas into a gas-phase hydrogenation column, where it is immediately converted into catalytic hydrogen. It is on the verge of becoming a reality. As mentioned above, in the suspension layer, a high conversion rate of crude heavy oil can be achieved at a relatively low temperature. As a result, the amount of crude heavy fraction vapor entrained in the produced gas stream is reduced, so that the deterioration of the shaped catalyst in the gas phase hydrogenation cylinder is reduced and its life is extended.

In Fig. 1, the generated gas stream separated in the high-temperature separation column 18 is mainly composed of vapor of coarse light and medium fractions decomposed and produced in the liquid phase hydrogenation column, and unreacted hydrogen, with a small amount of decomposed products. Contains gases (hydrogen sulfide, ammonia, water vapor, methane, ethane, propane, etc.) and crude heavy fraction vapor derived from vapor-liquid equilibrium at the exit temperature of the high-temperature separation tube. Such a generated gas stream is continuously sent to the next gas phase hydrogenation column 19, where it is subjected to catalytic hydrogenation at high temperature and high pressure to further refine and lighten the crude light and medium fractions.

As the shaped hydrogenation catalyst used in the gas phase hydrogenation cylinder, it is effective to use commonly used hydrorefining catalysts and hydrocracking catalysts together. For example, it is preferable to use a three-way catalyst in which molybdenum sulfide and nickel sulfide are supported on alumina and silica-alumina, respectively. The liquid hourly space velocity of the vapor of the coarse, light and medium fractions fed into the gas phase hydrogenation cylinder is usually 0.5 to 3 hr ^-1 , the pressure is the same as that of the liquid phase hydrogenation cylinder, and the reaction temperature is 390 to 460°C.

Even in a gas-phase hydrogenation cylinder, a rapid rise in reaction temperature occurs due to the reaction heat, but if a known method is used, such as dividing a packed bed into several stages and feeding cooling hydrogen between each stage, the reaction can be improved. You can freely adjust the temperature. Line 37 is a high pressure hydrogen supply pipe for cooling. Hydrogen for cooling is recycled hydrogen.
Any new hydrogen for replenishment may be used.

(d) Separation/recovery of produced oil and hydrogen circulation process The main components are the vapor of the produced oil rich in light fractions produced by hydrorefining and hydrocracking in the gas phase hydrogenation cylinder 19, and unreacted hydrogen. After the airflow is cooled by the heat exchanger 15, an appropriate amount of distilled water is injected from the branch pipe 68 as necessary to prevent the precipitation of ammonium carbamate, and the airflow is further cooled by the water cooler 20 to form the vapor of the produced oil. After condensing and liquefying the
1 and separated into liquid produced oil, condensed water, and circulating gas whose main component is unreacted hydrogen. The former is taken out of the high-pressure reaction system through line 22 and sent to a refining/fractionation plant to produce light oil and medium oil products. The latter is circulated to the reaction system via the high-pressure hydrogen circulation pump 23 and line 14 and used repeatedly. In addition to hydrogen, this circulating gas contains hydrocarbon gases such as methane, ethane, and propane, which are hydrogenation reaction byproducts, as well as small amounts of hydrogen sulfide, ammonia, water vapor, and
Since carbon dioxide and other gases are mixed in and accumulated, a portion of the gas is discharged from the high-pressure reaction system through line 24 and sent to a hydrogen recovery factory via gas purification equipment. Line 25 is a supply line for fresh hydrogen (high pressure) at the start of operation, but is also used as a replenishment line for hydrogen consumed during operation. When replenishing fresh hydrogen through line 37 for cooling the gas phase hydrogen cylinder, line 25
The amount of hydrogen replenishment from

(e) Slurry circulation process Slurry remains at the bottom of the high-temperature separation column. This is extracted from the bottom of the high-temperature separation cylinder,
After the slurry is cooled down to the maximum operating temperature of the pump 27 using an air cooler 26,
Warm slurry storage tank 28/line 3 with cooler
The slurry is circulated and fed into the raw material supply tank 12 via the normal pressure slurry storage tank 31 and pump 32. In addition, the pump 27 can circulate the hot slurry or the pump 29 can directly circulate the hot slurry to the liquid phase hydrogenation cylinder. By directly circulating the hot slurry or hot slurry, the temperature of the liquid phase hydrogenation cylinder can be easily adjusted. A method of circulating the slurry to the raw material supply tank and a method of directly circulating the slurry to the liquid phase hydrogenation cylinder may be used in combination.

By circulating the slurry in this way, the finely divided hydrogenation catalyst in the slurry is repeatedly fed into the liquid phase hydrogenation column to form a liquid phase suspension catalyst layer, and the heavy residual oil in the slurry is also repeatedly hydrogenated. Eventually, all or almost all of it undergoes hydrorefining and hydrocracking to be converted into coarse, light and medium fractions.

The upper limit of the concentration of fine powder solids such as catalyst in the slurry is approximately 40% by volume (4 volumes of fine powder solids and 6 volumes of residual oil), so the operating conditions must be adjusted so that the slurry concentration in pumps 27, 29 and 32 does not exceed this upper limit. Adjust conditions. If the temperature of the liquid-phase hydrogenation cylinder increases, the amount of light and medium distillate vapor produced will increase, and if the hourly feed rate of feedstock oil is constant, the amount of liquid heavy residual oil will decrease. As the heavy residual oil decreases, the catalyst concentration increases.
However, the catalyst concentration in the residual oil slurry must not exceed the above limits. Therefore, either the hourly feed rate of feedstock oil is increased or the temperature of the liquid phase hydrogen cylinder is lowered. In actual operation, the liquid phase hydrogenation column 17 is
Measures and controls the hourly flow rate of feedstock oil, hydrogen, hot slurry, and hot slurry.

By combining the above five processes into a comprehensive process, two independent plants, a high-pressure liquid-phase hydrogenation plant for crude heavy oil and a high-pressure gas-phase hydrogenation plant for crude, light and medium oil, can be used in tandem. It will be possible to achieve great results by achieving and obtaining these effects with a single series-type plant.

In the present invention, the embodiments of the above-mentioned comprehensive process are further devised with new ideas as described in the following sections (listed in numerical order of the claims), resulting in technical improvements and economic efficiency of the present serial high-pressure hydrogenation process. We are making improvements.

(2) Hydrogenation in the high-temperature separation column In the high-temperature separation column, the overflow from the liquid-phase hydrogenation column is fed from the top of the column for simple gas-liquid separation, and the produced gas is transferred from the column storage section to the bottom of the column. The slurry may be extracted. However, in order to use the space inside the cylinder more effectively, a slurry reservoir layer is formed inside the cylinder, and the overflow from the liquid phase hydrogenation cylinder is sent to the bottom of the high-temperature separation cylinder. It is more efficient if the generated airflow rises in the reservoir layer and then undergoes gas-liquid separation. By doing so, the residual oil in the reservoir can be further hydrogenated by the large amount of hydrogen present in the generated gas stream. Since the catalyst exists in a concentrated state in this reservoir, it further promotes the nuclear hydrogenolysis of the polycyclic aromatic compound which is difficult to react. In this case, the effect will be greater if the height of the reservoir is as high as the design allows. The dotted line 38 in FIG. 1 indicates the line through which the overflow from the liquid phase hydrogenation column 17 is fed to the bottom of the high temperature separation column 18.

(3) Separation of coarse and heavy fraction vapor from the product air stream In order to extend the life of the shaped hydrogenation catalyst packed in the gas phase hydrogenation cylinder as long as possible, it is necessary to separate the coarse and heavy fraction vapor entrained in the product air stream from the high temperature separation cylinder. It is important to adjust the vapor content of the fraction to be as low as possible. The reason is that this crude and heavy fraction is thermally decomposed and decomposed even in gas phase hydrogenation.
This is because polycondensation tends to occur and free carbon is produced, and this free carbon adheres to the active surface of the shaped hydrogenation catalyst together with metal sulfides such as nickel vanadium, gradually reducing its activity.

If the feedstock oil is rich in components with a linear chemical structure and has a small content of asphaldenes or biumene, such as paraffin-based petroleum residue or shale crude oil, the desired hydrogenation rate can be obtained. The liquid phase hydrogenation temperature can be kept fairly low. As a result, the content of crude heavy fraction vapor in the produced gas stream corresponding to the vapor-liquid equilibrium partial pressure at the temperature at the top of the liquid-phase hydrogenation column decreases. In terms of components, it is of course mainly composed of linear structures that are difficult to generate free carbon when decomposed in a gas-phase hydrogenation cylinder. Therefore, the gas stream produced in the liquid-phase hydrogenation cylinder can often be fed directly to the gas-phase hydrogenation cylinder.

However, if the feedstock oil is naphthene-based petroleum residue or low-temperature tar, which has a high content of asphaldenes and bityumenes and is rich in components with polycyclic chemical structures, it is difficult to obtain the desired hydrogenation rate. The reaction pressure and reaction temperature of liquid-phase hydrogenation to obtain hydrogen gas are higher, and as a result, the equilibrium partial pressure of the crude heavy fraction at the upper temperature of the liquid-phase hydrogenation cylinder is higher, which increases its content in the product stream. As a result, the activity of the gas phase hydrogenation catalyst decreases more quickly.

In order to suppress this, the generated air stream separated from the slurry in a high-temperature separation column is cooled to lower the temperature to a certain extent, and the vapor of the coarse and heavy fraction entrained in the generated air stream is condensed and separated. The purpose is achieved.

As mentioned above, the reaction temperature of the liquid phase hydrogenation cylinder is 370
~440°C, but by simply lowering the temperature of the produced gas stream to 350~390°C, which is the starting temperature of the gas-phase hydrogenation reaction, a considerable amount of the crude and heavy fraction vapor is condensed and separated. However, if the catalyst is further cooled to a temperature below the gas phase hydrogenation reaction initiation temperature, the separation efficiency can be further increased and the life of the shaped hydrogenation catalyst can be further extended.
In this case, it is necessary to reheat the generated gas stream after separating the vapor of the crude heavy fraction to a temperature equal to or higher than the gas phase hydrogenation reaction initiation temperature. This reheating is facilitated by heat exchange with the uncooled product stream or overflow from the liquid phase hydrogenation column. Alternatively, a heat exchanger may be provided in the gas phase hydrogenation cylinder to perform reheating using the heat of the gas phase hydrogenation reaction.

This operation of cooling and reheating the generated airflow can also be performed by sending the generated airflow separated by the high-temperature separation column to a high-pressure device (not shown) that is completely separate from the high-temperature separation column. However, it is more advantageous in terms of thermal economy and equipment to perform the slurry separation successively in the same high-temperature separation column.

(4) Separation of crude heavy fraction vapor by fractional condensation Figure 3 shows a demultiplexer that condenses and separates the entrained crude heavy fraction vapor by indirectly cooling the generated airflow after separating the slurry. This figure shows an example of the internal structure of a high-temperature separation cylinder 18 provided with. A cooling coil 43 is provided inside the demultiplexer 42 installed in the upper space of the cylinder, an air inlet 44 open at the lower end, and an air outlet 45 at the upper end, and a coiled heat exchanger 46 is installed between the high temperature separation cylinder and the dephlegmator. A flash nozzle 47 for the overflow from the liquid phase hydrogenation cylinder is provided above the space.

A mixed fluid of the product air flow and slurry overflowing from the top of the liquid phase hydrogenation cylinder is guided through a line 51.
It is fed into the high temperature separator 18 from the nozzle 47.
The mixed fluid introduced is first cooled considerably by contacting the outer surface of the coil of the heat exchanger 46. Thereafter, the slurry continues to descend and falls into the slurry storage section 48, where it is temporarily stored. The generated airflow is reversed to separate gas and liquid from the slurry, enters the interior of the demultiplexer 42 from the lower end air inlet 44, contacts the outer surface (cooling surface) of the cooling coil 43, and is further cooled. During this cooling process, the vapor of the coarse and heavy fraction entrained in the generated air stream condenses on the outer surface of the cooling coil.
It falls into the slurry storage section 48 and becomes part of the slurry. In this way, most of the vapor of the coarse and heavy fraction is condensed and separated, and the remaining generated airflow passes through a mist collector 49 and an air outlet 45, which are filled with a Raschitz ring installed at the top of the decentralizer, and undergoes heat exchange. Vessel 4
After being heated through the inside of the coil 6 and recovering the temperature above the gas phase hydrogenation reaction initiation temperature, it is led to the gas phase hydrogenation cylinder through a line 52.

Here, the refrigerant, such as a gas such as hydrogen or a liquid such as high-boiling point oil, sent to the cooling coil 43 of the decentralizer cools the generated air flow and is heated itself, so it is directly separated at high temperature. The usual idea is to discharge it outside the cylinder, cool it with a cooler outside the system, and then recirculate it for use, and there is no harm in doing so.

However, in this serial high-pressure hydrogenation method, after hydrogen at room temperature and high pressure is used as a refrigerant, it is mixed directly into the product air stream from which the vapor of the crude heavy fraction has been separated, and is used in the next gas-phase hydrogenation reaction. It can be dried. This method not only eliminates the need for a refrigerant and cooler outside the system, but also increases the molar ratio of hydrogen to coarse, light, and medium distillate vapors, which is even more advantageous for gas-phase hydrogenation reactions. .

That is, as shown in FIG.
3 is left open at the inlet of the mist collector 49, and hydrogen at room temperature and high pressure is fed through the line 50. This hydrogen passes through the inside of the cooling coil 43, cools the generated air flow, and heats itself. It then exits the cooling coil at the inlet of the mist collector 49 and joins the remaining product stream from which most of the crude heavy fraction vapor has been removed. Note that the hydrogen for cooling may be fresh hydrogen for replenishment or circulating hydrogen.

(5) Separation of crude and heavy distillate vapor by fractional distillation Figure 4 shows that by cooling the generated air stream from separated slurry by directly contacting it with liquid light/medium oil (hereinafter referred to as rectified oil) at around room temperature, This figure shows an example of the internal structure of a high-temperature separation column 18 equipped with a fractionator that condenses and separates the vapor of the entrained coarse and heavy fraction. A fractionator 53 installed in the upper space of the cylinder is provided with a plurality of shelves 54, an air inlet 55 open at the lower end, and an air outlet 56 at the upper end, and the coiled heat exchanger 46 is connected to the high temperature separation cylinder for fractionation. A flash nozzle 47 for the overflow from the liquid phase hydrogenation cylinder is provided above the space.

A mixed fluid of the product air flow and slurry overflowing from the top of the liquid phase hydrogenation cylinder is guided through a line 51.
When the mixed fluid is introduced into the high-temperature separation cylinder 18 through the nozzle 47, the mixed fluid first contacts the outer surface of the coil of the heat exchanger 46 and is cooled considerably. Thereafter, the slurry continues to descend and falls into the slurry storage section 48. The generated airflow is reversed and separated from the slurry, enters the interior of the fractionator 53 through the lower end air inlet 55, and ascends the tray 54. On the way, it comes into contact with the rectifying oil that is sent through the line 58 and descends from the upper part of the tray, and is cooled, and its temperature drops. During this time, the crude and heavy fraction vapor in the generated air stream is cooled and condensed, and at the same time is also subjected to the fractionation effect, descends and falls into the slurry storage section 48, and becomes part of the slurry. The rectifying oil exchanges heat with the rising generated airflow while descending on the tray, vaporizes, and merges with the generated airflow. In this way, most of the vapor of the coarse and heavy fraction is condensed and separated, and the generated airflow is combined with the vapor of the rectified oil. is heated through the outlet 56 and inside the coil of the heat exchanger 46;
After the temperature has been restored to a temperature higher than the gas phase hydrogenation reaction starting temperature, it is led to the gas phase hydrogenation cylinder through a line 52.

The rectifying oil used here is a distillate with a boiling point of 200°C or higher under normal pressure obtained by fractionating the oil produced from the gas-phase hydrogenation cylinder connected next, or medium oil from outside the system. be able to. This method is more effective than the partial condensation method of indirect cooling explained in the previous section. However, since this has the negative effect of lowering the molar ratio of hydrogen to coarse, light and medium fractions, it may be necessary to increase the amount of circulating hydrogen used or to increase the reaction pressure in advance.

(6) Regeneration of attenuated liquid phase hydrogenation catalyst In the method of the present invention, thermal decomposition of metal sulfides and asphaltenes/bityumens produced by hydrogenation of polymeric metal-organic complex compounds also depends on the type of feedstock oil. - It is often difficult to completely prevent free carbon resulting from polycondensation from adhering to the surface of a suspended catalyst. However, since it is in the form of a fine powder, the outer surface area of the catalyst is 2
This is more than an order of magnitude larger, and therefore the rate of decay of catalyst activity based on the above-mentioned adhesion becomes very slow. Moreover, in this case, as described below, there is a simple method
It has the advantage of being easy to play. That is, to explain this with reference to FIG. 1, a portion of the hot slurry is sent from the storage tank 28 via a line 30 to an atmospheric slurry storage tank 31, and from there is sent to an attrition machine 35 such as a tube mill or ball mill by a pump 32. If the catalyst particles are supplied and thoroughly milled at a temperature of about 60 to 90°C for a long period of time, for example, several hours to several tens of hours, solid foreign matter such as sulfides of metals such as nickel and vanadium and free carbon attached to the surface of the catalyst particles will be removed. Mechanically exfoliated, the catalyst once again exposes its active surface and regains most of its activity. If the slurry has a high viscosity and therefore has a weak grinding effect, an appropriate amount of medium oil may be added to reduce the viscosity.

The slurry after grinding is returned to normal pressure slurry storage tank 3.
1 and is supplied to the raw material supply tank 12 via a line 33 by a pump 32, and is supplied to a liquid phase hydrogenation cylinder 17 via a heat exchanger 15 and a preheater 16 by the pump 13.
It is circulated to the bottom of the tank. This catalyst regeneration process using the attritor can also be performed intermittently depending on the deactivation state of the catalyst. However, it is preferable to carry out the process continuously, since the activity of the catalyst can be maintained at a constant value, and the capacity of the attritor can be small. Such a catalyst regeneration method using a grinder cannot be applied to conventional shaped or coarse-grained catalysts, and can only be implemented with fine-powder catalysts.

(7) Preventing the generation of free carbon during the preheating process Even during steady operation, in order to prevent the generation of free carbon due to thermal decomposition and polycondensation in the feedstock preheater, a finely divided hydrogenation catalyst is applied to the feedstock before preheating. Suspension is desirable. For this purpose, a portion of the hot slurry is extracted from the storage tank 28 and sent to the atmospheric slurry storage tank 31 via a line 30, and from there is continuously supplied to the raw material supply tank 12 via a pump 32 and a line 33. In this way, it is not necessarily necessary to constantly add a new catalyst to the feedstock oil. The amount of catalyst suspended in the feedstock oil varies depending on the reactivity of the feedstock oil and the activity and particle size of the catalyst, but may be approximately 0.5 to 3% by volume.
However, if there is no need to directly feed the hot slurry or hot slurry to the liquid-phase hydrogenation cylinder for temperature adjustment, there is no problem in mixing the entire amount of the slurry separated in the high-temperature separation cylinder with the feedstock oil before preheating.
The ability to have the catalyst present from the preheating stage is one of the advantages of using a suspended bed of finely divided hydrogenation catalyst in liquid phase hydrogenation, which cannot be achieved with a fixed catalyst bed.

(8) Control of the concentration of solid foreign matter in the suspended layer Solid foreign matter such as sulfides of metals such as nickel and vanadium and free carbon, which are exfoliated from the catalyst surface by the catalyst regeneration method explained in section (6), are Similarly, it is accumulated in a suspended state in the suspension layer inside the liquid phase hydrogenation cylinder. Although the presence of these solid foreign substances is not harmful to the hydrogenation reaction itself, if the accumulated amount increases over a long period of operation, it will cause undesirable effects such as a decrease in the fluidity of the suspended layer and slurry. Therefore, there is a certain limit to the amount of these things that can be accumulated.

To this end, a portion of the slurry extracted from the high-temperature separation column is cooled and depressurized, then continuously or intermittently discharged to the outside of the reaction system, and fresh catalyst is continuously or intermittently replenished into the reaction system. In this way, it is necessary to maintain the concentration of suspended catalyst in the liquid phase hydrogenation cylinder within a predetermined range, and at the same time to control the concentration of solid foreign matter such as free carbon and metal sulfides accumulated in the suspended layer to below a predetermined limit. be. The predetermined limit for the concentration of solid foreign matter is a value determined in relation to the catalyst concentration, and when it is necessary to maintain a high catalyst concentration, the upper limit of the solid foreign matter concentration must be set low; When appropriate, the upper limit of the solid foreign matter concentration may be set high.
As already mentioned, the upper limit of the concentration of fine solids in the slurry is approximately 40% by volume, so the predetermined limit for the concentration of solid foreign matter must be set so that the total concentration of the fine hydrogenation catalyst and solid foreign matter does not exceed approximately 40% by volume. stipulate.

In FIG. 1, the new catalyst is fed into the raw material supply tank 12 from the line 34 in the form of catalyst-containing heavy oil in which it is heavily suspended. On the other hand, normal pressure slurry storage tank 31
A slurry discharge line 36 is provided at the outlet.

In the slurry discharged from line 36,
It may contain large amounts of sulfides of nickel and vanadium as well as catalysts,
In any case, this will be stored separately and sent to a resource recovery factory as appropriate.

The finely divided hydrogenation catalyst in the suspension layer is in the form of highly active sulfides, but the new replenishment catalyst is not limited to only sulfides, but also finely divided metal oxides, metal hydroxides, and metals. Even if it is in the form of oxyacid, heteropolyacid, metal salt of organic acid, etc.
Those that are converted into sulfides by the reaction in the liquid phase hydrogenation cylinder can be used without any problem.

(9) Connection and use of multiple gas-phase hydrogenation cylinders There are some differences in the generated airflow sent from the high-temperature separation cylinder to the gas-phase hydrogenation cylinder depending on the type and reactivity of the feedstock oil. However, even after being hydrorefined in a liquid-phase hydrogenation cylinder, a considerable amount of the vapor of the polar polymer compound containing heteroatoms still contaminates even after the vapor of the crude heavy fraction is condensed and separated by the method described above. I'll come.

In order to successfully hydrogenate this, it is necessary to connect and install multiple gas phase hydrogenation cylinders. For example, if two cylinders are connected, the first cylinder is used to convert a polar polymer compound into a hydrocarbon. A molded catalyst having excellent refining ability, that is, catalytic hydrorefining ability, such as a molybdenum sulfide catalyst supported on alumina, is packed. The second cylinder that follows is filled with a molded catalyst that is not easily poisoned by hydrogen sulfide, ammonia, and steam and has excellent catalytic hydrogen cracking performance for hydrocarbons, such as a three-way catalyst of molybdenum sulfide and nickel sulfide using silica alumina as a carrier. do. In this way, by filling and using catalysts with different performance in two or more gas-phase hydrogenation cylinders, it is possible to achieve the two objectives of hydrorefining and hydrocracking at once, and increase productivity. can.

FIG. 2 illustrates a case where the first gas phase hydrogenation cylinder 19a and the second gas phase hydrogenation cylinder 19b are connected in series and used. Lines 37a and 37b indicate cooling hydrogen supply pipes to be sent to the first and second gas phase hydrogenation cylinders, respectively, and other symbols are the same as in FIG. 1.

(10) Prevention of short pass in the liquid phase hydrogenation cylinder The catalyst layer in the liquid phase hydrogenation cylinder is prone to back mixing due to hydrogen bubbles, and a portion of the feedstock oil fed from the bottom inlet of the hydrogenation cylinder is There is a risk that the product may pass through the shot and reach the outlet at the top of the hydrogenation column without sufficient reaction time and overflow. On the other hand, for heat dissipation, it is desirable to mix the fluids at the inlet and outlet. An example of a method for satisfying these two contradictory demands will be described below.

FIG. 5 is a conceptual diagram of the internal structure of the cylinder for this purpose, in which an inner cylinder 59 with open upper and lower ends is installed in the center of the liquid phase hydrogenation cylinder 17, and a space between the inner cylinder and the outer cylinder. 60 is provided with a plurality of stages of dispersion plates 61. The dispersion plate has a structure similar to a perforated plate, which is simple and convenient.

Raw material oil is fed into the bottom of the cylinder from line 62.
The mixture of the fine hydrogenation catalyst (slurry) and hydrogen is blocked by the umbrella 63 and moves toward the outer periphery, rising through the space 60 between the inner cylinder and the outer cylinder. Since the space 60 is partitioned into multiple stages by the scattering board 61,
Even if back-mixing occurs at each stage, the raw oil to be cracked will not pass through from the inlet to the outlet in a short period of time. Half of the slurry forming the suspended layer at the top of the liquid-phase hydrogenation cylinder and the generated gas flow overflow from line 64 and are sent to the high-temperature separation cylinder, and the remaining slurry flows into the internal space 6 of inner cylinder 59.
5 and circulates below the space 60.

Reference numeral 66 is an inlet line for a mixed fluid of raw material oil and hydrogen sent from the preheater, and 67 is a circulation line for slurry sent from the high-temperature separation column.

(11) Connecting and using multiple liquid phase hydrogenation cylinders Generally, in order to advance the liquid phase hydrogenation reaction to a high degree, multiple liquid phase hydrogenation cylinders are connected and used. In particular, in the case of feedstock oil with low reactivity, it is necessary to use two or more liquid phase hydrogenation cylinders connected together.

FIG. 2 shows an embodiment thereof, in which a first liquid phase hydrogenation cylinder 17a and a second liquid phase hydrogenation cylinder 17b are directly connected. During steady operation, the slurry is extracted from the bottom of the high-temperature separation column 18 and sent to the air cooler 26 and thermal slurry circulation pump 2.
7 to the bottom of the first liquid phase hydrogenation cylinder 17a. The catalyst-containing produced oil in this cylinder is discharged together with hydrogen from the upper part of the first liquid phase hydrogenation cylinder 17a through the inner cylinder 41, and is fed into the lower part of the second liquid phase hydrogenation cylinder 17b. In addition, the hot slurry in the storage tank 28 is pumped through the line 39 or line 40 by the pump 29.
It is sent to the lower part of the first liquid phase hydrogenation cylinder 17a and/or the second liquid phase hydrogenation cylinder 17b. By adjusting the amount of hot slurry fed to each cylinder, the reaction temperature of the first liquid phase hydrogenation cylinder and the second liquid phase hydrogenation cylinder can be adjusted.
The reaction temperature of each liquid-phase hydrogenation cylinder can be artificially adjusted separately.

When the feedstock oil contains a relatively large amount of hard asphalt or bitumen, the first liquid phase hydrogenation cylinder is operated at a relatively low temperature to convert the hard asphalt or bitumen into soft asphalt, bitumen, or heavy hydrocarbons. After changing the temperature, if you transfer it to the second liquid phase hydrogenation cylinder which operates at a relatively high temperature,
Generation of free carbon can be effectively suppressed.

By using two or more liquid-phase hydrogenation cylinders in this way, the operating conditions for each cylinder can be set separately according to the components and reactivity of the feedstock oil, making it more effective than when using only one cylinder. It is often possible to carry out liquid phase hydrogenation of the feedstock.

(12) Operation method at the start of operation Finally, we will discuss various points that should be especially noted when operating the plant of the present invention. As mentioned above, crude heavy oils, especially those containing a large amount of asphaldene and bityumene, tend to undergo polycondensation and generate free carbon when the hydrogen partial pressure is too low or when the oil is overheated. Free carbon not only adheres to the catalyst surface and attenuates its activity, but also tends to increase heat transfer resistance and flow path resistance when it adheres and accumulates on heating surfaces such as preheating furnaces and bent portions of pipes. In order to avoid such inconveniences as much as possible, the operating conditions such as temperature and flow rate in each part of the raw material supply, reaction, and circulation systems must be adjusted so that they are within predetermined values set as optimal conditions. It is important to adjust the

Especially at the beginning of operation, various problems are likely to occur until the various conditions reach the specified values, so first start operation using thermally stable heavy oil with a low content of asphaltenes and bityumens. The temperature of the preheater and the temperature of the liquid phase hydrogenation cylinder are
After operating conditions such as pressure, hydrogen circulation amount, and catalyst suspension concentration reach near predetermined values, the incoming heavy oil is gradually switched to raw material oil and normal operation begins.

Conversely, when the operation is stopped, the feedstock oil is switched to the thermally stable heavy oil mentioned above, and the heating surface of the preheater is thoroughly cleaned to prevent the feedstock oil from adhering to or remaining on the heating surface before the operation is stopped. do. If necessary, perform further cleaning with light/medium oil fluid.

The thermally stable heavy oil used herein refers to one that is difficult to generate free carbon through thermal decomposition and polycondensation, and suitable heavy oil has a small content of asphaldene bitiumen and unsaturated compounds.

Effects The above explanation clearly shows the effects of the present invention, and these will be listed below.

(1) Since the catalyst used in liquid-phase hydrogenation is in fine powder form, it can be used in a suspended state and at a high concentration. As a result, the active surface area of the catalyst becomes significantly larger, and as a result, the contact effect increases significantly, and at the same time, the attenuation due to the coating of by-product metal sulfides and free carbon becomes extremely slow, and as a result, the activity of the catalyst is maintained for a long time. can.

(2) Since the catalyst can be used continuously for a long time, regeneration operations are significantly reduced, and there is almost no regeneration loss, so even if it is expensive, a catalyst with high hydrogenation activity can be used.

(3) As a result of being able to use a highly active catalyst with a significantly large effective surface area, a high hydrogenation reaction rate of feedstock oil can be achieved in a liquid phase hydrogenation cylinder at a relatively low reaction temperature. Because the temperature is low, the amount of crude and heavy fraction vapor entrained in the product air stream is reduced, so the deterioration of the shaped catalyst in the gas phase hydrogenation cylinder is reduced.
Its lifespan will be extended. In addition to this, by cooling the generated airflow from the liquid phase hydrogenation cylinder to gradually lower the temperature and condensing and removing the entrained crude heavy fraction vapor, it is possible to The deterioration of the shaped catalyst in the conversion tube is further reduced and its lifespan is significantly extended.

(4) As a result of being able to use a highly active catalyst with a significantly large active surface area, it is now possible to sufficiently soften raw oils containing a large amount of asphaltenes and bityumenes, which were difficult to process using conventional methods. can.

(5) The vapors of crude, light and medium fractions decomposed and produced in the liquid-phase hydrogenation cylinder are fed directly to the gas-phase hydrogenation cylinders connected in series and reacted without being condensed or liquefied. Energy loss is small, equipment costs are reduced, and light oil can be produced all at once from raw crude heavy oil. In other words, the production effects that can be achieved by two independent plants, a liquid-phase hydrogenation plant and a gas-phase hydrogenation plant, can be achieved with one liquid-phase and gas-phase series hydrogenation plant. The effect is extremely large.

(6) Since regeneration of the finely divided hydrogenation catalyst can be achieved in the form of a slurry by a simple mechanical grinding method, the cost of regeneration equipment and inventory of preliminary catalysts can be reduced. In addition, the catalyst can be regenerated and replenished without stopping the hydrogenation operation.

(7) Even if the feedstock oil is unstable and easily generates free carbon due to thermal decomposition and polycondensation, the finely divided hydrogenation catalyst can be dispersed and suspended in the feedstock oil and fed into the high-pressure reaction zone together with hydrogen. heat exchange and
The generation of free carbon during the preheating process can be sufficiently suppressed.

[Brief explanation of drawings]

Figures 1 and 2 are process diagrams for carrying out the method of the present invention, Figure 3 is an example of the internal structure of a high-temperature separation cylinder used in carrying out the present invention, and Figure 4 is the internal structure of a high-temperature separation cylinder. Another example, FIG. 5, is a conceptual diagram showing the internal structure of a liquid phase hydrogenation cylinder. A... Normal pressure section, B... High pressure section, 11... Line, 12
...Raw material supply tank, 13...Raw material pump, 14...Line, 15...Heat exchanger, 15a...First heat exchanger, 1
5b...Second heat exchanger, 15c...Third heat exchanger, 1
6... Preheater, 17... Liquid phase hydrogenation cylinder, 17a... First
Liquid phase hydrogenation cylinder, 17b...Second liquid phase hydrogenation cylinder, 18
...High temperature separation column, 19... Gas phase hydrogenation column, 19a... First gas phase hydrogenation column, 19b... Second gas phase hydrogenation column, 2
0...Water cooler, 21...Low temperature separation column, 22...Line, 23...High pressure hydrogen circulation pump, 24...Line,
25... High pressure hydrogen line, 26... Cooler, 27... Pump, 28... Hot slurry storage tank, 29... Pump, 3
0... Line, 31... Ordinary pressure slurry storage tank, 32... Pump, 33... Line, 34... Line, 35... Attritor, 36... Slurry discharge line, 37... Hydrogen supply line, 37a... Hydrogen supply line, 37b... Hydrogen supply Line, 38...Line, 39...Line, 40
... Line, 41 ... Inner pipe, 42 ... Decentralizer, 43 ... Cooling coil, 44 ... Air inlet, 45 ... Air outlet, 4
6... Coiled heat exchanger, 47... Flush nozzle, 48... Slurry storage section, 49... Mist collector, 50... Line, 51... Line, 52... Line, 53... Fractionator, 54... Shelf, 55... Air inlet, 56... Air outlet, 57... Mist collector, 58
... Line, 59 ... Inner cylinder, 60 ... Space, 61 ... Dispersion plate, 62 ... Line, 63 ... Umbrella, 64 ... Line, 6
5...Inner space of inner cylinder, 66...Feeding line, 67...
Circulation line, 68...branch pipe.

Claims (1)

[Scope of Claims] 1. Crude heavy oil is first subjected to high-temperature, high-pressure catalytic hydrogenation in the liquid phase to produce crude, light and medium fractions, and then refined and lightened by high-temperature and high-pressure catalytic hydrogenation in the gas phase. In the continuous light oil production method, (a) Preheated raw material crude heavy oil, finely powdered hydrogenation catalyst, and excess hydrogen are continuously fed into the bottom of the liquid phase hydrogenation cylinder, and In a state in which finely powdered hydrogenation catalyst is dispersed and suspended in crude heavy oil to form a liquid phase suspended catalyst layer, a part of the crude heavy oil is catalytically hydrogenated to produce vapors of coarse light and medium fractions. (b) a process of continuously producing vapor of the crude light and medium fractions obtained at that time, a generated gas stream mainly consisting of unreacted hydrogen, and a gaseous stream consisting of finely powdered hydrogenation catalyst and residual crude and heavy oil; A step of continuously overflowing the catalyst residual oil slurry flow from the upper part of the liquid phase hydrogenation cylinder and sending it to the next high temperature separation cylinder, where the generated gas flow and the catalyst residual oil slurry flow are separated into gas and liquid, (c ) The vapor of the crude, light and medium fractions separated in the high-temperature separation column and the produced gas stream mainly composed of hydrogen are continuously extracted from the upper part of the high-temperature separation column, and are then kept in the gas phase with a formed hydrogenation catalyst packed bed. (d) Process of further refining and lightening the crude light and medium fraction vapors by feeding them into a hydrogenation cylinder and subjecting them to catalytic hydrogenation. A process in which a gas stream consisting mainly of steam and unreacted hydrogen is cooled, the vapor of the produced oil rich in light fractions is liquefied and separated from unreacted hydrogen, and the hydrogen is recycled to the liquid phase hydrogenation cylinder for use. e) A step in which the catalyst residual oil slurry separated in step (b) is extracted from the bottom of the high-temperature separation column and reused by circulating it into the liquid-phase hydrogenation column.It is characterized by combining the above five steps. Continuous production method of light oil. 2 Form a catalyst residual oil-containing slurry storage layer in the high-temperature separation column, and feed the overflow from the liquid phase hydrogenation column to the bottom of the high-temperature separation column, so that the generated airflow in the overflow flows into the storage layer. Claim 1, characterized in that the residual oil in the reservoir is further hydrogenated by the hydrogen in the generated gas stream, and the residual oil in the reservoir is further hydrogenated by the hydrogen in the generated gas stream.
The method described in section. 3 The generated air stream separated from the catalyst residual oil slurry in the high-temperature separation column is cooled to lower the temperature, and the vapor of the crude heavy fraction entrained in the generated air stream is condensed.
After separation, the remaining crude, light and medium fraction steam and the produced gas stream, which is mainly composed of hydrogen, are continuously heated with or without heating, while maintaining the temperature above the gas phase hydrogenation reaction initiation temperature. 2. The method according to claim 1, characterized in that it is fed into a phase hydrogenation cylinder. 4. A patent characterized in that the generated airflow separated from the catalyst residual oil slurry is brought into contact with the cooling surface of a dephlegmator installed in the gas phase part of a high-temperature separation cylinder to cool the generated airflow, thereby lowering the temperature of the generated airflow. The method according to claim 3. 5 In a fractionator installed in the gas phase inside the high-temperature separation cylinder, the produced air stream separated from the catalyst residual oil slurry is brought into direct contact with the liquid light/medium oil supplied from outside the cylinder and cooled. 4. A method according to claim 3, characterized in that the temperature of the produced air stream is lowered. 6. By cooling and depressurizing a portion of the catalyst residual oil slurry extracted from the bottom of the high-temperature separation column and thoroughly grinding it in a grinder, free carbon attached to the surface of the finely divided hydrogenation catalyst in the catalyst residual oil slurry is removed.・After mechanically peeling off solid foreign substances such as metal sulfides,
The method according to claim 1, characterized in that the slurry containing catalyst residual oil is circulated and fed to the liquid phase hydrogenation column. 7. Continuously mix the catalyst-containing residual oil slurry extracted from the bottom of the high-temperature separation cylinder with the raw material crude heavy oil before preheating, and preheat it with hydrogen while the fine hydrogenation catalyst is suspended in the raw material crude heavy oil. 2. The method according to claim 1, characterized in that the hydrogen gas is fed into a liquid phase hydrogenation cylinder from the hydrogen gas. 8 A part of the catalyst residual oil slurry extracted from the bottom of the high-temperature separation cylinder is cooled and depressurized, and then continuously or intermittently discharged from the reaction system, and new catalyst is continuously or intermittently replenished into the reaction system. In this way, the concentration of suspended catalyst in the liquid phase hydrogenation cylinder is maintained within a predetermined range, and at the same time, the concentration of solid foreign substances such as free carbon and metal sulfides accumulated in the suspended catalyst layer of the liquid phase hydrogenation cylinder is controlled. The method according to claim 1, characterized in that the temperature is controlled to be below a predetermined limit. 9 Multiple gas-phase hydrogenation cylinders are connected and installed, the leading cylinder is filled with a shaped catalyst with excellent catalytic hydrogenation refining ability, and the subsequent cylinder is filled with a shaped catalyst with excellent catalytic hydrogenation cracking ability. A method according to claim 1, characterized in that filling. 10 An inner cylinder with open upper and lower ends is installed in the center of the liquid-phase hydrogenation cylinder, and multiple stages of dispersion plates are arranged in the space between the inner cylinder and the outer cylinder, and the crude and heavy oil to be fed is The finely powdered hydrogenation catalyst and hydrogen are dispersed and mixed to rise through the space between the inner cylinder and the outer cylinder, and a part of the catalyst residual oil slurry present in the upper part of the liquid phase hydrogenation cylinder is Claim 1 characterized in that the circulation is made to descend inside the inner cylinder.
The method described in section. 11. The method according to claim 1, characterized in that a plurality of liquid phase hydrogenation cylinders are connected and used.