JPS6195091A - Hydrogenative pyrolysis of heavy hydrocarbon - Google Patents

Abstract

PURPOSE:Heavy hydrocarbon oil is rapidly heated, pyrolyzed, then subjected to hydrogenolysis in the presence of a catalyst to give high oil from which contaminants such as sulfur, nitrogen, metals and asphalten are removed with high stability. CONSTITUTION:Heavy hydrocarbon oil is rapidly heated in a furnace, then pyrolyzed in the soaking tube to obtain the pyrolysate. The product is, as it is, or after separation of low-boiling fractions are removed, subjected to hydrolygenolysis in the presence of a hydrogenation catalyst such as a hydrogenation metallic catalyst such as copper supported on a porous inorganic oxide such as alumina at 350-450 deg.C, 50-250kg/cm<2>G, 0.1-5Hr<-1> liquid space velocity, 100-2,000Nl/lH2/oil ratio to give light oil.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for hydropyrolysis of heavy hydrocarbon oils.

[Prior art]

Light thermal cracking (called visbreaking) and catalytic hydrocracking are widely known technologies for processing heavy hydrocarbon oils around the world. The visbreaking method is a method in which heavy hydrocarbon oil is subjected to a mild heat treatment within a range that does not impair the stability of the produced oil to reduce the viscosity of the heavy hydrocarbon. However, this method cannot be expected to remove impurities such as metal sulfur and nitrogen from hydrocarbon oil. Although some of the heavy hydrocarbon oil is converted to light oil through cracking.

A polycondensation reaction occurs in parallel, producing polymers such as asphaltene and toluene-insoluble matter. on the other hand.

Catalytic hydrocracking can remove sulfur, nitrogen, metals, etc. from heavy hydrocarbon oil, improving quality and producing oil with high added value, but the lightening rate is low. Therefore, the production volume of middle distillates (kerosene, light oil) is low.

For the reasons mentioned above, when processing heavy hydrocarbon oil,
A method has been proposed in which the above two methods are combined to improve the lightening rate and produce oil of good quality (Japanese Patent Publication No. 54-22
No. 444, Special Publication No. 57-205484).

However, in the above combination method, sludge (coke-like substance) is generated in the preceding thermal decomposition step.

Sludge accumulates on the catalyst layer of the fixed bed catalyst device in the latter stage, eventually increasing the pressure loss and making it impossible to continue operation. This coke-like material is produced by the precipitation of polymers, typically toluene-insoluble matter, produced in the polycondensation reaction during the thermal decomposition process, and increases rapidly when the lightening rate exceeds a certain limit.

Therefore, in order to prevent clogging of the catalyst bed in a catalytic hydrocracking apparatus, an operating method that does not generate coke-like substances during the thermal cracking process is very important.

The visbreaking method includes a heating furnace decomposition method, a soaker decomposition method, or a combination of both methods. The heating furnace decomposition method is generally widely practiced as a method in which thermal decomposition is carried out at a high temperature and in a short time at a heating furnace outlet temperature in the range of 460 to 520°C. However, due to the high temperature conditions and the radiation from the heating furnace burner, the surface temperature of the reaction tube becomes high, resulting in so-called coking, where coke deposits and adheres to the inner surface of the tube, and the period of stable operation is said to be limited to 3 to 6 months. . On the other hand, the soaker decomposition method allows the reaction to take place for a long time at a lower temperature than the heating furnace decomposition method, and the coking phenomenon within a single reaction vessel is mild, allowing stable operation for a long period of about one year. However, since this soaker requires a long reaction time, it is necessary to have a larger reactor volume than for furnace decomposition, and it is generally a large-diameter vertical drum, which is simply a large empty tank. For this reason, a reverse mixing flow occurs in a large-diameter soaker drum compared to a piston flow typified by a small-diameter tube reaction tube, and a residence time distribution occurs in the reactor. As mentioned earlier, when the decomposition severity (lightening rate) increases (this is due to an increase in temperature or an increase in reaction time)
, polycondensation compounds are produced, but in the case of this soaker cracking method, the long-term residence material in the reaction vessel undergoes excessive thermal history and coke-like substances precipitate. Therefore, compared to the tubular cracking method, the soaker cracking method has the disadvantage that sludge is generated at a lower overall lightening rate.

〔the purpose〕

The present invention is characterized in that the front k,
J&M □3o□Oh. ′) [structure
According to the present invention, hydrocarbon oil is rapidly heated in a heating furnace, then thermally decomposed in a tubular soaking device, and then the resulting thermally decomposed oil is used as it is/or a low boiling point fraction is added to the hydrocarbon oil. After decomposition and removal, the temperature is 350-450℃ and the pressure is 50℃.
~250kg/C4G, liquid space velocity 0.1~5Hr-7
, a H2/oil ratio of 10o to 2ooo NQ/Q is provided.

[Feedstock oil]

Examples of the heavy hydrocarbon oil used in the present invention include atmospheric distillation residue oil of petroleum, vacuum distillation residue oil, tar sand oil, shale oil, coal liquefied oil, etc., and the type thereof is not particularly limited.

[Heating of raw oil]

In the present invention, the raw material oil is first rapidly heated using a tubular heating furnace, and the heating conditions are generally at a temperature of 380 to 520"C, preferably 420 to 480"C.
°C, pressure 50-250 kg/cJG, preferably 100
~200kg/cnfG, residence time [coil volume (a)
/liquid thermometer (15°C) (I/min)] is 220 or less, and thermal decomposition in the heating furnace is limited as much as possible. The temperature and residence time in this heating furnace are such that the lightening rate ph is 172
Hereinafter, it is preferable to select from 175 to 215. In this case, the weight reduction rates ph and Ps are defined as follows.

Ph=(1--)xlOO(1) Ps=(1--)X100 (2)
Ph: Lightening rate in the heating furnace Ps: Lightening rate of the produced oil obtained from the soaking device A: Weight of the fraction of 538°C or higher in the raw oil B: 538°C or higher of the fraction of the produced oil from the heating furnace Weight of the fraction C: Weight of the fraction of 538°C or higher in the oil produced from the soaking device In heating the feedstock oil using this tubular heating furnace, hydrogen or hydrogen-containing gas is supplied to the heating furnace along with the hydrocarbon oil. The addition of hydrogen or hydrogen-containing gas increases the liquid flow rate in the pipe and lowers the hydrocarbon partial pressure, resulting in the effect of suppressing the coking phenomenon.

The addition ratio of hydrogen or hydrogen-containing gas to the raw material oil is 50 to 200 ON12/u, preferably 100 to 50
ON Q/n.

[Pyrolysis using soaking device]

The product oil obtained from the tubular heating furnace is pyrolyzed in a tubular soaking device. In this case, the pipe diameter (inner diameter) of the soaking device is generally selected to be the same or larger than the pipe diameter of the heating furnace.

The linear velocity of the liquid hydrocarbon oil in this soaking device requires a liquid Reynolds number sufficient to be considered as a piston flow, and is usually 0.5 m/sec to 10 m/sec, preferably 1.5111/sec to 5 inclination. /second range is recommended. When this wave line velocity is smaller than the above range, the kinetic energy of the fluid is small, and the polycondensate resulting from the reaction tends to solidify and adhere to the wall surface of the reaction tube, and when it is larger than the above range, the pressure loss within the reaction tube increases significantly. Not practical.

Note that the wave linear velocity is expressed by the following formula.

R: Wave linear velocity (m/sec) Q: Hydrocarbon oil supply amount (kg/sec) Density of hydrocarbon oil at 9815°C (kg/m) A:
Pipe flow cross-sectional area (a) The length/inner diameter ratio (L/D) of the soaking device pipe is 10
It is preferable to set it to 0 or more.

The inlet temperature of this soaking device is 380-520℃,
Preferably 420-480℃, pressure 50-250kg
/cI#, preferably 100-200kg/CIIG,
The residence time is between 2 and 60 minutes, preferably between 5 and 30 minutes.

In the case of the present invention, the thermal decomposition using this soaking device is preferably carried out under hydrogen pressure, and the hydrogen pressure is 50 to 25%.
Advantageously, it is carried out at 0 kg/dG. In the thermal decomposition of hydrocarbon oils, the asphaltene content in the resulting oil usually increases, and the content increases as the thermal decomposition becomes more severe.

O, 1. . Surprisingly, when thermal decomposition is carried out under 78, 11.8, □1 conditions, the asphaltene content does not increase and tends to be equal to or lower than that of 1M feed oil.

The soaking device of the present invention is composed of a tubular member (tubular coil) as described above, and is preferably equipped with a decoking burner.

In this case, the decoking burner is used to remove coke that adheres to the inside of the tubular coil when the operation is stopped by decoking (a method of burning and removing coke by introducing air and steam). It has a smaller capacity (approximately 20%) than the previous burner. This decoking burner can also be applied to temperature control of a soaking device. Conventional sky tower vessel type soaking devices had the disadvantage that the decoking operation was very difficult, but in the case of the present invention, the decoking operation is easy and such a disadvantage does not occur. .

[Hydrotreatment of pyrolysis generated oil]

The thermally cracked oil obtained from the above-mentioned soaking device is hydrocracked as it is or after separating and removing a low-boiling fraction in the presence of a hydrotreating catalyst. This hydrogenolysis is carried out according to a conventionally known method, generally at a temperature of 350 to 450°C and a hydrogen pressure of 50 to 250 kg/cn?
G, liquid space velocity 0.1-5. The condition of Ohr″″1 is adopted. The hydrogenation catalyst is a conventionally known catalyst, and for example, one in which a hydrogenation-active metal component is supported on a porous inorganic oxide is used. In this case, as the porous inorganic oxide, various conventionally known synthetic or natural products such as γ-alumina, α-alumina, silica, magnesia, boria, zirconia, phosphine, chromia,
Titania, silica-alumina, alumina-boria.

Examples include synthetic products such as alumina phosphere, silica-magnesia, synthetic zeolite, and synthetic sepiolite, as well as naturally occurring products such as sepiolite, zeolite, bauxite, attapulgite, kaolin, and montmorillonite. As the hydrogenation active metal component, at least one metal selected from conventionally known metals, such as metals from Groups 1, 2, 2 and 2 of the Periodic Table, is used,
Specific examples of such materials include copper, vanadium, molybdenum, tungsten, cobalt, nickel, iron, etc. In particular, from the viewpoint of catalyst activity and life, combinations of group VIB and group II, For example, Co-No.
The use of Ni-Mo, N1-u, or Co-Ao-Ni combinations is preferred. Further, the hydrogenation-active metal component supported on the porous inorganic oxide is usually in the form of an oxide and/or a sulfide. The supported amount of the hydrogenation active metal component is 1 to 3 in terms of metal oxide relative to the porous inorganic oxide.
It is about 5% by weight.

The catalyst in the present invention may be in the form of powder, granules, or other forms.

Although it can be used in the form of molded products of various shapes, it is particularly advantageous to use it in the form of extruded molded products such as hollow cylinders, ellipsoids, trilobes, and multilobed shapes.

Its dimensions vary depending on the type of reaction bed, but are generally 0
．． 8-6.2+u+, preferably 1.0-3.1+nn
The catalyst used in the present invention has a pore volume of about 0.
．． 4-1.5cc/g, surface area 100-250ryf/
It is preferable to use one having physical properties of 50 to 400 g and pore size.

According to this hydrotreating step, impurities, sulfur content, nitrogen content, metal content, and asphaltene content in the product oil obtained in the thermal decomposition process or step 1 can be efficiently removed. In this case, since no sludge is produced as a by-product in the thermal decomposition process, catalyst clogging does not occur for a long period of time in this hydrotreating process, making it possible to stably decompose polycondensates such as asphaltene components. , the stability of the resulting hydrotreated oil is dramatically increased.

Next, the present invention will be explained in more detail with reference to the drawings.

The drawing shows a flow sheet for carrying out the method of the invention. In this figure, 3 is a tubular heating furnace, 6 is a tubular soaking device, 9 is a hydrotreating device, and 11 is a gas-liquid separator.

The feedstock oil introduced from pipe 1 is supplied through pipe 14, and together with make-up hydrogen passing through pipe 18, it is supplied through pipe 2 to tubular heating furnace 3, where it is heated to a temperature in the range of 380 to 480°C. After being heated for a short time, it is withdrawn through line 4, and introduced into the tubular V-#'f device 6 together with the make-up hydrogen through line 15 and the circulating hydrogen 8 through line 16. is,
It is thermally decomposed here. The pyrolysis products are withdrawn from the tubular soaking device 6 through line 7, mixed with circulating hydrogen through line 17, and sent via line 8 to the hydrotreater 9 for hydrotreating. be done.

The hydrotreated product passes through the pipe 10 to the hydrotreating device! 9 and sent to a gas-liquid separator 11 where the gas and liquid are separated, the hydrogen-containing gas is circulated through the pipe 12 to the pipe 16 and F, and the liquid product is passed through the pipe 16 and F. 13 and is extracted out of the system and either used as a product as it is or subjected to hydrogenation treatment for the purpose of improving the quality of the product.

〔effect〕

The present invention has the above configuration, and contaminants such as sulfur, nitrogen, metals, and asphaltene are removed.

In addition, a lightened wave with excellent stability can be obtained. Moreover, in the case of the present invention, the generation of coke and sludge is prevented in the thermal decomposition process.

In the hydrotreating process, the problem of catalyst clogging does not occur, and stable operation can be performed for a long period of time.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

As the raw material oil for the examples, a Middle Eastern vacuum residue oil having the properties shown below was used.

Table-1 Specific gravity (d15/4℃):
1.0360 Viscosity (IQO'C) (C
P): 8000n-hebutane insoluble content (wt%): 13.1 Sulfur content (wt%)
: 5.25 vanadium content (wt-p
pm): 150 nickel containing Ek (wt
, -ppm): 52 nitrogen content (wt
-ppm): 0.51 Conradson residual carbon content (Sit, %): 23.3'
(CCR) Toluene insoluble content (TI) (wt%):
o.

Distilled raw (vt, %) Distillate below 343°C: o.

343-538℃ fraction Near, 0538℃
Fractions above: 93.0 This feedstock oil is supplied to a tubular heating furnace together with hydrogen gas, heated, and then introduced into a tubular soaking device for pyrolysis, and the resulting pyrolysis product is directly hydrogenated. It was introduced into a processing equipment and subjected to hydrogenation treatment.

In this case, the tubular heating furnace is equipped with a tubular coil having an inner diameter of 4 mn+ and a length of 2 m (length to inner diameter ratio L/D = 500). The tubular soaking device is a tubular coil with an inner diameter of 4s+m and a length of 3m (length to inner diameter ratio L/D = 750
). The hydrotreating equipment uses a commercially available hydrotreating catalyst (Ni-Co-No/A n 20 z )
It consists of a cylindrical reaction tube with an inner diameter of 37 mm and a length of 200 c+i filled with .

Next, the reaction conditions will be described.

(1) Tubular heating furnace reaction temperature ('C): 460 reaction pressure (
kg/cdG): 140Liquid residence time (min)
;2 Hydrogen supply rate (NΩ/Q): 200 (2) Soaking device reaction temperature Inlet temperature ("C): 425 Outlet temperature ("
C): 415 reaction pressure (kg/a#G)
: 140 Liquid residence time (min) = 24 Hydrogen supply rate (LQ/Ω) : 500 (3) Hydrogenation unit reaction temperature ('C) : 395 Hydrogen pressure (kg/a#G) : 140 Liquid hourly space velocity ( hr-1): 0.2 The properties of the resulting oil thus obtained are shown in the following table.

Table 2 *2 Oil produced from hydrotreating equipment Note 1 The thermal stability shown in Table 2 was tested using the thermal decomposition test method ASTM D1661.

The evaluation criteria are as follows.

1... Stable 2... Slightly unstable 3... Unstable Comparative example In the example, an empty column □ vessel type reactor (inner diameter 2.5 cm, height 80cm).

Average reaction temperature 420℃, reaction pressure 140kg/c+JG
The experiment was conducted in the same manner except that an average liquid residence time of 18 minutes was used. The results are shown in Table-3.

Table 3 From the results shown in Table 2 and Table 3 above, in the case of the present invention, the increase in asphaltene content (n-hebutane insoluble content) in the thermal decomposition process is suppressed, the lightening rate increases, and It can be seen that the quality of the obtained hydrotreated oil is significantly improved.

[Brief explanation of drawings]

The drawing shows an example of a flow sheet for implementing the present invention. 3... Tubular heating furnace, 6... Tubular soaking device, 9
... Hydrogenation equipment, 11... Gas-liquid separator.

Claims (1)

[Claims] (1) After rapidly heating the hydrocarbon oil in a heating furnace and then thermally decomposing it in a tubular soaking device, the resulting thermally decomposed oil remains as it is or after separating and removing the low boiling point fraction, Temperature 350-450℃, pressure 50-250k
g/cm^2G, liquid space velocity 0.1~5Hr^-^1,
A method for hydrothermal cracking of hydrocarbon oil, characterized in that hydrocracking is carried out using a hydrotreating catalyst under conditions of a H_2/oil ratio of 100 to 2000 Nl/l.