JPH0542478B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a method for treating heavy hydrocarbon oil thermal decomposition products. [Prior Art] Conventionally, in order to obtain light oil from heavy hydrocarbon oil, a method is known in which heavy hydrocarbon oil is heated to a high temperature in the presence or absence of hydrogen to decompose and lighten the oil. . By the way, in the thermal decomposition of such heavy hydrocarbon oil, the thermal decomposition products obtained are high temperature and tend to generate coke.
Its processing is difficult, and according to traditional methods,
For example, a treatment method in the presence of hydrogen as shown in FIG. 5 has been adopted. That is, as can be understood from FIG. 5, in the conventional method, heavy hydrocarbon oil introduced from line 56 is divided into circulating hydrogen (line 64) and make-up hydrogen (line 58) passing through line 57. The high temperature pyrolysis products obtained in the furnace 50 are introduced into the mixer 51 where they are mixed with the low temperature pyrolysis products coming through line 83. It is mixed with oil and quenched. The quenched product is then introduced into a gas-liquid separator 52, where the liquid component is separated from the gas component and sent through line 65 to the distillation column 53 for distillation treatment, while the gas component is through line 62 to condenser 54;
Here, hydrocarbon components having 5 or more carbon atoms in the gaseous components are condensed and extracted from the line 86, and are removed from the distillation column 5.
3, while the hydrogen and C1-C4 hydrocarbon components are withdrawn through line 63, passed through compressor 55, and combined with heavy hydrocarbon oil through line 56 with make-up hydrogen from line 58. mixed. In the distillation column 53, a part of the distillate obtained from the top of the column is circulated through a line 74, a valve 75, a line 76, a line 84 and a pump 85 to the mixer 51 for quenching the thermal decomposition product, A portion of the bottom oil also passes through line 81, valve 82, line 83 and pump 85 to mixer 51.
is circulated. In addition, in FIG. 5, the reference numeral 6
7 and 78 are coolers, 69 is a tank, and 71 is a pump. As is clear from the conventional method for treating pyrolysis products, in the conventional case, the pyrolysis products from the heating furnace 50 are passed through the mixer 51 to the low-temperature overhead distillate obtained from the distillation column 53. and part of the bottom oil and are rapidly cooled, the mixer 51
The volume of the quenched product obtained is increased by the added pyrolysis product oil used for quenching, and therefore the volume of the quenched product is increased by the amount of added pyrolysis product oil used for the quenching, and therefore the volume of the quenched product is increased by the amount of the added pyrolysis product oil used for the quenching. The problem is that the equipment is large in size and has low efficiency.Furthermore, the steam obtained by heat recovery has to be of medium and low pressure, so the recovery efficiency and economic effect are insufficient. Ta. [Objective] An object of the present invention is to provide a method for treating a heavy hydrocarbon oil thermal decomposition product, which eliminates the above-mentioned problems found in conventional methods. [Structure] According to the present invention, when treating a pyrolysis product whose main component is a liquid oil at a temperature of 420 to 520°C obtained by pyrolyzing heavy hydrocarbon oil, (i) the pyrolysis product an indirect heat exchange process in which the product is quenched by indirect heat exchange with cooling water in the form of a gas-liquid mixture without separating it into gas and liquid, and generates high-pressure and high-temperature steam; (ii) the product obtained from the indirect heat exchange process; The indirect heat exchange step is performed using an indirect heat exchange device having a triple tube structure consisting of an outer tube and a double tube inserted into the outer tube. , cooling water is introduced into the inner pipe of the double pipe, and a heavy hydrocarbon oil thermal decomposition product is introduced into the gap between the outer pipe and the double pipe, and the cooling water is introduced into the inner pipe of the double pipe. The high-temperature, high-pressure steam is led out as high-pressure, high-temperature steam from the outer tube of the double tube, and the resulting high-temperature, high-pressure steam is guided into a pressure regulating container that is maintained at high temperature and high pressure and contains cooling water inside, and the steam is introduced into the container. A method for treating a heavy hydrocarbon oil thermal decomposition product is provided, which comprises mixing the heavy hydrocarbon oil pyrolysis product into cooling water. As the raw material oil in the present invention, various heavy hydrocarbon oils for which lightening raw materials are conventionally used are used, such as normal pressure residual oil, vacuum distillation residual oil, etc. In addition to various residual oils such as, deasphalted oil, coal liquefied oil, etc. In the present invention, the raw material oil is thermally decomposed in a heating furnace. In this case, various conventionally known heating furnaces may be employed, but generally a tubular heating furnace is employed. Further, various types of soakers such as a tubular type or a Bessel type can be combined with this tubular type heating furnace. Thermal cracking of heavy hydrocarbon oils is carried out in the presence or absence of hydrogen. According to the present invention, a thermal decomposition product consisting of a gas-liquid mixed phase obtained by thermal decomposition treatment of heavy hydrocarbon oil is first subjected to indirect heat exchange with cooling water without gas-liquid separation. At the same time, the cooling water is converted into high-pressure, high-temperature steam by heating at that time.
Next, the thermal decomposition product quenched by this indirect heat exchange is subjected to gas-liquid separation treatment (if not in the presence of hydrogen, gas-liquid separation treatment is not necessarily necessary) and sent to a distillation treatment step, Distilled. In the present invention, as described above, the pyrolysis product is indirectly heat exchanged with the cooling water. In this case, the indirect heat exchange device includes an outer tube and a tube inserted into the outer tube. A tubular heat exchanger with a triple tube structure consisting of double tubes is used. In such a tubular heat exchanger, thermal decomposition products are introduced into the gap formed between the outer tube and the double tube, cooling water is introduced into the inner tube of the double tube, and the The cooling water introduced into the inner pipe of the double pipe is discharged as high-pressure and high-temperature steam from the outer pipe of the double pipe. FIGS. 1 and 2 are cross-sectional explanatory views of the indirect heat exchange device used in the present invention. FIG. 1 shows two tubular heat exchangers A and B connected at their lower ends. In this figure, 1 indicates an outer tube, and 2 is a double tube inserted into the outer tube, which is composed of an inner tube 3 and an outer tube 4. The outer tube 1 of one heat exchanger A has a pyrolysis product introduction tube 5 in its upper part, and the outer tube 1 of the other heat exchanger B has a pyrolysis product discharge tube 6 in its upper part. However, the upper end of each outer tube 1 is sealed by a flange 7, and the lower end of each outer tube 1 is connected by a U-shaped connecting tube 8. The double tube 2 has a structure in which an inner tube 3 with an open lower end is inserted into an outer tube 4 whose lower end is sealed, and the upper end of the outer tube 4 is sealed with the inner tube 3. , the upper part of the double tube 2 extends above the outer tube 1. Also,
Each double pipe 2 has a steam discharge pipe 9 attached to its upper part, and the upper end of the inner pipe 3 of each double pipe is connected to each end of a cooling moisture pipe 11 having a cooling water inlet 10 in the middle. has been done. In such a heat exchanger, thermal decomposition products are introduced through the inlet pipe 5 of the outer tube 1 of one heat exchanger A, and are discharged from the outer tube 1 of the other heat exchanger B through the discharge tube 6. Ru. In addition, the cooling water is introduced from the inlet 10 of the distribution pipe 11, flows down inside the inner pipe 3 of each double pipe 2, and flows upward inside the outer pipe 4 of the double pipe 2, but in the meantime, The cooling water undergoes indirect heat exchange with the high-temperature pyrolysis products flowing through the outer tube 1 and becomes high-pressure and high-temperature steam, which is then discharged from the discharge pipe 9 attached to the upper part of the outer tube 4 of the double tube 2. be discharged.
On the other hand, the pyrolysis products are rapidly cooled by this heat exchange, and the quenched pyrolysis products are discharged from the discharge pipe 6 of the outer tube 1 of the heat exchanger B. The heat exchange device shown in FIG. 2 is structurally similar to that shown in FIG.
are connected to each other by a connecting pipe 20 at the upper part thereof, and have a pyrolysis product introduction pipe 21 and a pyrolysis product discharge pipe 22 at the lower end of each outer pipe 1. The indirect heat exchange device described above can be modified in various ways. For example, fins can be attached to the outer surface of the outer tube 4 of the double tube 2 to increase the heat transfer efficiency, and fins can be added to the outer surface of the outer tube 4 of the double tube 2. A plurality of double tubes can be inserted, and two or more indirect heat exchange devices shown in FIG. 1 or 2 can be combined. According to the research conducted by the present inventors, when using the above-mentioned indirect heat exchange device, it is possible to efficiently cool the thermal decomposition products, and it is possible to thermally decompose the low-temperature thermal decomposition product oil unlike the conventional method. Since the cooling process is not directly mixed with the product and cooled, the volume of the processed material does not increase due to the cooling process, and therefore, the efficiency of the apparatus is significantly improved compared to conventional methods. In addition, such indirect heat exchange allows high-pressure, high-temperature steam to be recovered as a by-product, which is extremely advantageous from the standpoint of energy conservation. When the pyrolysis products are cooled using an indirect heat exchange device as described above according to the present invention, the temperature of the pyrolysis products discharged from the indirect heat exchange device is within a temperature range compatible with subsequent processing. , below 440℃,
The temperature is usually set in the range of 380-420°C. That is, the pyrolysis products obtained from the pyrolysis furnace are generally at a high temperature of 450 to 500°C, easily generate coke, and are difficult to handle. It is cooled to a temperature of 360-440°C, preferably 380-420°C by an indirect heat exchanger. In the case of the indirect heat exchange device used in the present invention, the cooling rate of the pyrolysis products can be controlled by the temperature and flow rate of the cooling water introduced into the inner tube of the double tube 2, so even if the residence time is short, the pyrolysis products can be It is possible to rapidly cool objects to the required temperature. In addition, in the present invention, the thermal decomposition products are indirectly heat exchanged with cooling water in the form of a gas-liquid mixture without being subjected to gas-liquid separation treatment, so that the heat transfer during the indirect heat exchange is is very good. In addition, there is no need for special restrictions on the operating pressure of indirect heat exchange equipment, but when pyrolysis is carried out in the presence of hydrogen, the operating pressure must be 80 atm or higher, usually 100 to 200 atm, and the operating pressure must be discharged from the indirect heat exchange equipment. The steam used is also of similar high pressure. Next, in the present invention, a method in which thermal decomposition is carried out in the presence of hydrogen will be explained in more detail with reference to flow sheets shown in FIGS. 3 and 4. In FIG. 3, 50 is a heating furnace, 26 is a pressure regulating vessel, and 27 and 28 are each shown in FIG.
An indirect heat exchange device consisting of a pair of heat exchangers A and B is shown. Heavy hydrocarbon oil as a feedstock is introduced into the heating furnace 50 through lines 56 and 59, but when pyrolysis is carried out in the presence of hydrogen, prior to its introduction, circulating hydrogen from line 64 and 58 and other supplementary hydrogen, and introduced into the heating furnace 50 in the form of a mixture with hydrogen. The conditions for this heating furnace 50 are generally a temperature of 420 to 520°C, preferably
The temperature is 440 to 500°C and the pressure is 1 to 250 kg/cm ² G, preferably 5 to 200 kg/cm ² G. When pyrolysis of heavy hydrocarbon oil is carried out in the presence of hydrogen, the hydrogen partial pressure is 30
-250Kg/ ^cm2G , preferably 100-200Kg/ ^cm2G . The cooling water passes through a line 30 and enters a heating coil 31 disposed in the flue section of the heating furnace 50, where it is preheated, and then passes through a line 34 and is introduced into the pressure regulating vessel 26. The thermal decomposition products consisting of a gas-liquid mixture obtained in the heating furnace 50 are extracted through lines 32 and 33, and are transferred to indirect heat exchangers 27 and 2, respectively.
8 will be introduced. In addition, cooling water from the pressure regulating vessel 26 is introduced into these indirect heat exchange devices via lines 37 and 38, respectively, and in these indirect heat exchange devices, cooling water and thermal decomposition products are exchanged. An indirect heat exchange takes place between the pyrolysis products and the pyrolysis products to be cooled to the required temperature, and the cooling water is converted to high-pressure and high-temperature steam. The high pressure and high temperature steam obtained in the indirect heat exchangers 27 and 28 is passed through lines 35 and 36, respectively.
is introduced into the pressure regulating vessel 26 through the. The high pressure and high temperature steam generated here is extracted through line 44. This pressure regulating vessel 26 is generally operated at about 300° C. and 100 atmospheres. The thermal decomposition products cooled in the indirect heat exchangers 27 and 28 are extracted through lines 41 and 42, respectively, and introduced into a gas-liquid separator 52 shown in FIG. 4 via a line 43. Note that, in the symbols shown in FIG. 4, the same symbols as those shown in FIG. 5 have the same meanings. Next, referring to FIG. 4, line 4
The thermal decomposition products introduced through line 3 into a gas-liquid separator 52 (not necessarily required when not in the presence of hydrogen) are separated into gas and liquid here, and the gaseous components are passed through line 62. The high-boiling point components in the gaseous components, usually hydrocarbon components having 5 or more carbon atoms, are condensed through the condenser 54, and the condensate is passed through the line 86.
It is extracted through the distillation column 53 and sent to the distillation column 53. On the other hand, the low boiling point hydrocarbon gas containing hydrogen is pressurized by the compressor 55 and then circulated through the line 64 to the heating furnace 50 shown in FIG. 3. The liquid component (thermal decomposition product oil) obtained in the gas-liquid separator 52 is introduced into the distillation column 53 through a line 65, where it is separated into naphtha, gas oil, vacuum gas oil, and vacuum residual oil. is line 73,
Gas oil is discharged through line 82, vacuum gas oil is discharged through line 81, and vacuum residual oil is discharged through line 80. [Effects] The present invention has the above-mentioned configuration, and since a special indirect heat exchange method is adopted for cooling the thermal decomposition products,
Compared to the conventional cooling method shown in FIG. 5, in which low-temperature pyrolysis product oil is directly mixed with the pyrolysis product, it is introduced into equipment systems such as a gas-liquid separator 52, a distillation column 53, and a condenser 54. The liquid flow rate is significantly reduced, so that with the invention it is possible to significantly downsize the system. Furthermore, in the case of the present invention, since an indirect heat exchange device with a special triple-pipe structure is used, it is possible to significantly suppress the generation of coke during heat exchange, and the water used as a cooling medium is heated under high pressure and high temperature. It is recovered as steam and can be used as an energy source for various purposes. [Example] Next, the present invention will be explained in more detail with reference to Examples. Example A heavy hydrocarbon oil was thermally decomposed according to the flow sheet shown in FIGS. 3 and 4, and then the resulting thermal decomposition product was treated. The properties of the raw material oil and produced oil and the processing conditions in this case are shown in relation to the flow sheets shown in FIGS. 3 and 4. (1) Raw material oil (residual residual oil) Specific gravity (d15/4℃): 1.04 Viscosity (100℃) (cp): 8800 N-heptane insoluble content (wt%): 12.6 (2) Line 56 (raw oil) Flow rate (Kg/hr): 100 Temperature (℃): 300 Pressure (Kg/cm ² G): 180 (3) Pyrolysis conditions Temperature (℃): 480 Pressure (Kg/cm ² G): 160 Liquid residence time ( (min): 20 Hydrogen supply rate (Nl/l): 500 (4) Pressure regulator 26 Pressure (Kg/cm ² G): 100 Temperature (°C): 310 (5) Line 44 (steam) Flow rate (Kg/hr) ) : 13 Temperature (℃) : 310 Pressure (Kg/cm ² G) : 100 (6) Line 30 (cooling water) Flow rate (Kg/hr) : 13 Temperature (℃) : 110 (7) Line 32 or 33 ( Thermal decomposition products) Flow rate (Kg/hr): 55.9 Temperature (℃): 480 Pressure (Kg/ ^cm2G ): 160 (8) Line 37 or 38 (cooling water) Flow rate (Kg/hr): 33 Temperature ( ℃) : 310 Pressure (Kg/cm ² G) : 100 (9) Line 35 or 36 (high pressure high temperature steam) Flow rate (Kg/hr) : 33 Temperature (Kg/cm ² G) : 310 Pressure (Kg/cm ² G): 100 (10) Line 43 (cooled pyrolysis products) Flow rate (Kg/hr): 111.8 Temperature (°C): 400 Pressure (Kg/cm ² G): 160 (11) Line 63 (Gas components) Flow rate (Kg/hr): 11.8 (12) Line 80 (vacuum residual oil) Flow rate (Kg/hr): 65.1 Specific gravity (d15/4℃): 1.08 (13) Line 81 (vacuum gas oil) Flow rate (Kg/hr) :20.7 Specific gravity (d15/4℃) :0.95 (14) Line 82 (gas oil) Flow rate (Kg/hr) :8.6 Specific gravity (d15/4℃) :0.84 (15) Line 73 (naphtha) Flow rate (Kg/hr) ): 3.7 Specific gravity (d15/4℃): 0.77

[Brief explanation of drawings]

FIG. 1 is a cross-sectional explanatory view of one example of the indirect heat exchange device used in the present invention, and FIG. 2 is a cross-sectional explanatory view of a partially modified example thereof. FIGS. 3 and 4 show flow sheets of the method of the present invention, with FIG. 3 showing the previous stage and FIG. 4 showing the subsequent stage. FIG. 5 shows a flow sheet of the conventional method. 1... Outer pipe, 2... Double pipe, 5, 6... Pyrolysis product introduction or discharge pipe, 7... Flange, 8, 2
0... Connecting pipe, 9... Steam discharge pipe, 11...
Cooling moisture piping, A, B... Heat exchanger, 26...
Pressure adjustment vessel, 50... Heating furnace, 52... Gas-liquid separator, 53... Distillation column, 54... Condenser, 55...
...compressor.

Claims (1)

[Claims] 1. Temperature obtained by thermally decomposing heavy hydrocarbon oil
When treating pyrolysis products whose main component is liquid oil at a temperature of 420 to 520°C, (i) the pyrolysis products are indirectly heated with cooling water in the form of a gas-liquid mixture without gas-liquid separation; (ii) a step of distilling the liquid pyrolysis product oil obtained from the indirect heat exchange step; , an indirect heat exchange device with a triple tube structure consisting of an outer tube and a double tube inserted into the outer tube is used, and cooling water is supplied to the inner tube of the double tube and water is supplied between the outer tube and the double tube. Heavy hydrocarbon oil pyrolysis products were respectively introduced into the gaps, and the cooling water introduced into the inner tube of the double tube was led out as high-pressure and high-temperature steam from the outer tube of the double tube. A heavy hydrocarbon oil pyrolysis product characterized in that high temperature, high pressure steam is guided into a pressure regulating vessel held under high temperature and high pressure and containing cooling water therein, and mixed into the cooling water in the vessel. Processing method.