A method and reaction system for processing inferior heavy oil

Abstract

The application discloses a processing method and a reaction system for inferior heavy oil, and the method comprises the following steps: (1) inferior heavy oil is contacted with a solvent to perform solvent extraction, and an extracted liquid is obtained; after solvent recovery, an extracted oil is obtained; the obtained raffinate is subjected to stripping desolventization to obtain raffinate oil; (2) the extracted oil is further separated into a gasoline fraction, a diesel fraction and a hydrogenated tail oil after being subjected to hydrotreatment, wherein the hydrogenated tail oil is used as catalytic cracking device feed; (3) the raffinate oil and catalytic cracking slurry are mixed and then used as a gas-making raw material to enter a POX gas-making unit to obtain hydrogen or synthesis gas; and the solvent is selected from one or a mixture of several of pentane, hexane, heptane and naphtha. The method and the reaction system can yield more light oil products and chemical materials, reduce the harshness of heavy oil deep processing device operation, prolong the service life of a catalyst and the operation cycle of a device, and realize the purposes of full processing conversion of the heavy oil and zero discharge of the heavy oil.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of petroleum processing, and more particularly to a processing and utilization method of inferior heavy oil and a reaction system. BACKGROUND

[0002] With the increasingly stringent environmental regulations worldwide and the increasing demand for light oil products, the lightening technology of residual oil and the full utilization technology of heavy oil resources are increasingly valued. The problems of asphaltene coking and heavy metal poisoning of catalysts in residual oil deep processing become insurmountable obstacles, which seriously affect the service life of catalysts in heavy oil deep processing and the operation cycle of the device. On the other hand, with the increase of crude oil processing capacity, the degree of crude oil heavy and inferior is becoming more and more serious, and the yield of light oil products obtained by primary processing is gradually reduced; in order to fully utilize the crude oil resources, improve the utilization rate of crude oil resources and improve the light conversion rate of heavy oil, it is urgent to develop heavy oil processing and utilization technology. Therefore, with the deepening of the degree of heavy and inferior of crude oil and the increasing demand for light oil and chemical products, how to efficiently convert and utilize heavy oil and realize zero heavy oil production has become an opportunity and challenge for oil refining enterprises.

[0003] At present, there are many processes for processing inferior heavy oil and improving the light conversion rate of inferior heavy oil. In the pretreatment of heavy oil, the solvent deasphalting process is a recognized good separation technology for separating heavy oil to obtain good deasphalted oil. However, in order to obtain more deasphalted oil, it is necessary to bring about the problems of high softening point, high viscosity and difficult transportation of deoiled asphalt, and easy coking at high temperature, which causes the difficulty in utilization of deoiled asphalt. At present, one of the important indicators of POX gas making (partial oxidation gas making) technology for raw materials is that the viscosity at 270℃ is not more than 300 mPa.s.

[0004] CN100366709C discloses a combined process for processing heavy oil, which combines a decarburization process and a hydrogenation process to solve the problems of harsh operating conditions of a heavy oil hydrogenation treatment device and difficulty in utilizing hard pitch, etc. The heavy oil with high metal content, high gum and pitch content, high carbon residue, and high sulfur and nitrogen content is treated by a solvent deasphalting process and a coking process, and the deasphalted oil and coking wax oil after treatment are used as feedstock of the heavy oil hydrogenation treatment device to improve the properties of the feedstock of the heavy oil hydrogenation treatment device, ease the operating conditions of the heavy oil hydrogenation treatment device, extend the operating period of the heavy oil hydrogenation treatment device, and provide high-quality raw oil for downstream catalytic cracking devices. However, the metals, pitch, carbon residue, and sulfur and nitrogen in the heavy oil with high metal content, high gum and pitch content, high carbon residue, and high sulfur and nitrogen content are all enriched in the deoiled pitch after the solvent deasphalting process, and the petroleum coke generated by coking reaction of the deoiled pitch has high sulfur content and high ash content. Under the increasingly stringent environmental regulations, high-sulfur petroleum coke is difficult to sell and use, so the combined process for processing heavy components is not smooth.

[0005] CN102807892A discloses a combined process for processing heavy oil, in which the heavy oil raw material is treated by a solvent deasphalting process, the deasphalted oil phase is recovered by a solvent recovery process as a blending component of modified oil, the deoiled pitch phase does not need to remove the solvent, and is introduced from the bottom of the extraction tower and then injected into a dispersing solvent. The deoiled pitch phase is mixed with the dispersing agent and then enters a thermal cracking reactor for thermal cracking treatment. The deasphalted oil is mixed with the thermal cracking oil separated from the thermal cracking reaction product to obtain modified oil, and the solvent and heavy wax oil separated from the thermal cracking reaction product are returned to the solvent deasphalting process for recycling and used as mixed feedstock for removing pitch. However, this method not only does not recover the solvent in the deoiled pitch, but also inputs about 0.02-0.10 mass ratio of the solvent in the mixed solution of the deoiled pitch and the solvent as a dispersing solvent. The solvent used in the solvent deasphalting process is generally C3-C6 alkane, which brings a large amount of C3-C6 alkane into the thermal cracking reaction device, increases the load in the thermal cracking reaction process, and increases the gas partial pressure in the device due to the presence of light hydrocarbons, which affects the long-period stable operation of the thermal cracking reaction device.

[0006] CN102234536A discloses a heavy oil combined processing process, taking vacuum residue as the raw material of butane deasphalting device, controlling the yield of deoiled asphalt to be 50-60%, and taking the obtained deasphalting oil and catalytic cracking raw material as the raw material of catalytic cracking device, after the catalytic cracking process, the remaining catalytic cracking oil slurry which is difficult to crack is taken as the raw material of vacuum fractionation, and after the vacuum fractionation process, light oil slurry and top heavy oil slurry are obtained; part of the deoiled asphalt is taken as the raw material of fertilizer gasifier, and after the gasification process, the raw material gas is processed by subsequent processes to obtain synthetic ammonia product, and the other part of the deoiled asphalt is fully mixed with the top heavy oil slurry to produce high-grade road asphalt. The heavy oil combined processing process fully utilizes the vacuum residue, the process is simple, and the raw material can be supplied between the devices. However, the yield of the deasphalting oil obtained by the patent technology is low, only 40-50%, which does not fully utilize the heavy oil resources, and the energy consumption of the solvent deasphalting device is large; the deoiled asphalt and the top heavy oil slurry are mixed to produce high-grade road asphalt, and since the catalytic oil slurry is a thermal cracking product, it has poor thermal stability and contains catalyst powder, which can cause poor thermal aging performance and poor ductility of the high-grade road asphalt. SUMMARY

[0007] One of the technical problems to be solved by the present application is to provide a poor heavy oil processing method.

[0008] Another technical problem to be solved by the present application is to provide a poor heavy oil processing system.

[0009] In a first aspect, the present application provides a poor heavy oil processing method, comprising the following steps:

[0010] (1) contacting the poor heavy oil with a solvent for solvent extraction to obtain an extract liquid, and after solvent recovery, an extract oil is obtained; the obtained raffinate is subjected to stripping desolventization to obtain raffinate oil;

[0011] (2) further separating the extract oil after hydrotreatment into a gasoline fraction, a diesel fraction and a hydrotreated tail oil, wherein the hydrotreated tail oil is used as catalytic cracking device feed;

[0012] (3) mixing the raffinate oil and the catalytic cracking oil slurry, and then entering a POX gas making unit as a gas making raw material to obtain hydrogen or synthesis gas;

[0013] The solvent is selected from one or a mixture of the above-mentioned several of pentane, hexane, heptane and naphtha.

[0014] In a second aspect, the present application provides a poor heavy oil processing reaction system, which is applied to the above-mentioned poor heavy oil processing method and comprises a solvent extraction unit, a hydrogenation unit and a POX gas making unit.

[0015] The solvent extraction unit comprises a solvent extraction column, a solvent recovery column communicated with the upper part of the solvent extraction column, and a raffinate oil stripping column communicated with the lower part of the solvent extraction column; the bottom of the solvent recovery column is communicated with a hydrogenation unit, and the bottom of the raffinate oil stripping column is communicated with a POX gas making unit.

[0016] The hydrogenation unit comprises a hydrogenation reactor and a product fractionation column communicated in sequence.

[0017] Compared with the prior art, the method and the reaction system have the following beneficial effects:

[0018] The refined raffinate oil enriched with heavy metals and asphaltene obtained through high-selectivity separation has high softening point, high viscosity, high carbon content and low hydrogen-carbon atomic ratio, and a large amount of hydrogen is consumed in the light conversion process, so the refined raffinate oil is not suitable as a raw material for further lightening. However, using the refined raffinate oil as a POX gas making raw material can solve the problem of processing high-softening-point and high-viscosity heavy oil, realize zero heavy oil factory output, obtain hydrogen or synthesis gas needed by the enterprise, and improve the economic benefit of the oil refining enterprise. The high-softening-point and high-viscosity refined raffinate oil is difficult to transport, and is easy to coke at a high temperature. Mixing the catalytic oil slurry with the refined raffinate oil can reduce the viscosity of the refined raffinate oil in the system, so as to reduce the transportation temperature of the refined raffinate oil in the system, thereby reducing the coking tendency of the refined raffinate oil, and being also beneficial to the solvent recovery of the high-softening-point refined raffinate oil. The method for processing and utilizing the inferior heavy oil can produce more light oil and chemical materials, reduce the harshness of the operation of the heavy oil deep processing device, prolong the service life of the catalyst and the operation cycle of the device, realize the full processing conversion of the heavy oil and the zero factory output of the heavy oil. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a flowchart of an embodiment of the method for processing inferior heavy oil.

[0020] Reference signs:

[0021] 1 - vacuum residue 2 - extract liquid 3 - extract oil

[0022] 4 - hydrogenation separation product 5 - hydrogenation tail oil 6 - catalytic cracking oil slurry

[0023] 7 - oil slurry light component 8 - raffinate liquid 9 - oil slurry heavy component

[0024] 10 - raffinate oil / oil slurry mixture 11 - solvent separation column 12 - supercritical solvent recovery column

[0025] 13 - hydrogenation treatment unit 14 - catalytic cracking device 15 - oil slurry stripping column

[0026] 16 - solvent stripping recovery column 17 - POX gas making unit 18 - solvent

[0027] 20 - catalytic cracking product DETAILED DESCRIPTION

[0028] The specific embodiments of the present application are described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and explanatory in nature and are not intended to limit the application.

[0029] In the present application, the terms "upper", "lower", "bottom" are based on the relative position of the container or component. The "bottom" refers to the position of the container from the bottom to the top of 0-10%, the "lower" refers to the position of the container from the bottom to the top of 0-50%, the "upper" refers to the position of the container from the bottom to the top of 50-100%, and the "top" refers to the position of the container from the bottom to the top of 90-100%.

[0030] In a first aspect, the present application provides a method for processing poor heavy oil, comprising the following steps:

[0031] (1) The poor heavy oil is contacted with a solvent for solvent extraction to obtain an extract liquid, and the extract liquid is subjected to solvent recovery to obtain extract oil; the obtained raffinate is subjected to solvent stripping to obtain raffinate oil;

[0032] (2) The extract oil is further separated into a gasoline fraction, a diesel fraction and a hydroprocessed tail oil after being subjected to hydroprocessing, wherein the hydroprocessed tail oil is used as feedstock for a catalytic cracking device;

[0033] (3) The raffinate oil and catalytic cracking slurry are mixed and then introduced into a POX gas making unit as gas making raw material to obtain hydrogen or synthesis gas;

[0034] The solvent is selected from one or a mixture of the following solvents: pentane, hexane, heptane and naphtha.

[0035] Preferably, the solvent is pentane and / or hexane, more preferably a mixed solvent of pentane and hexane, which contains 60-90 wt% of pentane and 10-40 wt% of hexane.

[0036] Preferably, in step (3), the catalytic cracking slurry is introduced into a slurry stripper, and stripping gas is introduced to obtain slurry light hydrocarbon components and slurry heavy components after stripping, and the slurry heavy components are mixed with the raffinate oil and then introduced into the POX gas making unit. Preferably, the slurry light components are mixed with the extract oil obtained in step (1) and then subjected to hydroprocessing.

[0037] In the present application, the distillation range of the catalytic cracking slurry is in the range of 334-701°C, and the light hydrocarbons removed from the catalytic cracking slurry are diesel fractions, preferably with a distillation range of 333-360°C.

[0038] The operating conditions of the oil slurry stripper are: pressure 0.3-1.0 MPa, preferably 0.4-0.8 MPa, and the stripping gas is superheated steam, which is introduced into the middle and lower part of the oil slurry stripper to strip the catalytic cracking oil slurry.

[0039] Preferably, the raffinate and the oil slurry heavy component enter a raffinate oil stripping column for solvent recovery, and a mixture obtained from the bottom of the raffinate oil stripping column is used as a gas-making raw material to enter a POX gas-making unit.

[0040] In the present application, in step (1), the operating temperature of solvent extraction is 150-265°C, preferably 160-255°C, the operating pressure is 1.0-5.0 MPa, preferably 2.0-4.0 MPa, and the mass ratio of solvent to raw oil is 1.0-5.0:1, preferably 2.0-4.0:1.

[0041] In the present application, in step (1), the extract is used to recover solvent in a solvent recovery column, and the operating conditions of the solvent recovery column are: pressure 3.0-4.0 MPa, preferably 3.2-3.8 MPa, and temperature 200-300°C, preferably 230-270°C.

[0042] In the present application, in step (1), the raffinate is used to strip and recover solvent in a raffinate oil stripping column, and the operating conditions of the raffinate oil stripping column are: pressure 0.1-1.0 MPa, preferably 0.2-0.8 MPa, and temperature not higher than 320°C, preferably not higher than 300°C.

[0043] Preferably, in step (3), the mass ratio of catalytic cracking oil slurry to raffinate oil in the gas-making raw material is 1-7:1, preferably 1.5-5:1.

[0044] Preferably, the 270°C viscosity of the gas-making raw material is not more than 300 cP.

[0045] More preferably, the 270°C viscosity of the gas-making raw material is not more than 200 cP.

[0046] In the present application, the POX gas-making unit in step (3) refers to coal-to-hydrogen, petroleum coke gasification or heavy oil-to-hydrogen or gasification, and the POX reaction refers to gasification reaction, shift reaction and purification reaction, and the raw material is coal, petroleum coke or heavy oil, etc., and the product is hydrogen or synthesis gas (hydrogen and carbon monoxide). The reaction conditions of the POX gas-making unit are: 400-480°C and pressure 7.0-8.0 MPa, which are not limited in the present application.

[0047] In the present application, the inferior heavy oil has a carbon residue value of not less than 20%, preferably not less than 24%, an asphaltene content of not less than 7%, preferably not less than 9%, and a heavy metal (Ni+V) content of not less than 150 ppm.

[0048] In a second aspect, the present application provides a processing reaction system for inferior heavy oil, which is applied to any of the processing methods for inferior heavy oil described above, and is characterized by comprising a solvent extraction unit, a hydrogenation unit, and a POX gas making unit.

[0049] The solvent extraction unit comprises a solvent extraction tower, a solvent recovery tower in communication with the upper part of the solvent extraction tower, and a raffinate stripping tower in communication with the lower part of the solvent extraction tower; the bottom of the solvent recovery tower is in communication with the hydrogenation unit, and the bottom of the raffinate stripping tower is in communication with the POX gas making unit.

[0050] The hydrogenation unit comprises a hydrogenation reactor and a product fractionation tower in sequence.

[0051] Preferably, the processing reaction system further comprises an oil slurry stripping tower, the bottom of which is in communication with the solvent recovery tower, and the top of which is in communication with the hydrogenation reactor.

[0052] In the present application, the deoiled asphalt has a high softening point and a large viscosity, and it is difficult to transport and atomize when used as a POX raw material alone. The oil slurry produced by catalytic cracking is used as an external viscosity-reducing agent to reduce the viscosity of the deoiled asphalt, so that the deoiled asphalt can meet the viscosity requirement of the POX feedstock. The catalytic cracking oil slurry is first subjected to stripping to remove light hydrocarbons, and the removed light hydrocarbons are used as a raw material for hydrogenation treatment together with the extracted oil. The heavy components of the oil slurry after removal of light hydrocarbons are mixed with the raffinate oil to be used as a POX raw material. The separation selectivity of the solvent extraction unit can be improved. The processing method for inferior heavy oil provided by the present application can produce more light oil and chemical materials, reduce the harshness of the operation of the heavy oil deep processing device, provide suitable raw materials for the POX gas making device, produce hydrogen or synthesis gas required by the refinery, and realize full processing conversion and “zero” discharge of heavy oil.

[0053] In the present application, the extracted liquid in step (1) is preferably recovered by supercritical solvent recovery technology. Preferably, the proportion of the deasphalted oil obtained after supercritical solvent recovery to the inferior heavy oil is not less than 70%, preferably not less than 80%.

[0054] In the present application, the deasphalted oil obtained by separating the inferior heavy oil in the solvent extraction unit has an asphaltene removal rate of not less than 90% compared with the inferior heavy oil.

[0055] In the present application, the softening point of the deoiled asphalt is not less than 150°C; further preferably, the softening point of the deoiled asphalt is not less than 170°C.

[0056] The processing method and system of the poor heavy oil can realize the production of light oil and chemical materials, reduce the harshness of the operation of the heavy oil deep processing device, provide suitable raw materials for the POX gas making device, produce hydrogen or synthesis gas required by the refinery, realize the full processing conversion of the heavy oil and zero delivery of the heavy oil.

[0057] The preferred embodiments of the present application will be clearly and completely described below with reference to the drawings in the present application, but the drawings do not constitute a limitation on the present application.

[0058] Figure 1 The flowchart of one embodiment of the processing method of the poor heavy oil provided by the present application is shown in the figure. Figure 1 As shown in the figure, the vacuum residue 1 enters from the upper part of the solvent extraction tower 11, the solvent 18 enters from the lower part of the solvent extraction tower, the poor heavy oil raw material 1 and the solvent 18 are reversely contacted and separated in the solvent extraction tower 11, the extract 2 from the top of the solvent extraction tower 11 is subjected to solvent recovery in the solvent recovery tower 12, the solvent is recycled by heat exchange and cooling to 18 for reuse, the extract oil 3 obtained from the solvent recovery tower 12 is used as the raw material of the hydrogen treatment device 13, the hydrogen product 4 (including naphtha, hydrogenated gasoline and hydrogenated diesel) is obtained after the hydrogenation reaction and separation, the hydrogen tail oil 5 separated from the hydrogen treatment device 13 enters the catalytic cracking device 14 to obtain the catalytic product 20 (including catalytic gasoline and catalytic diesel) and the catalytic cracking oil slurry 6 after the catalytic reaction and separation, the catalytic cracking oil slurry 6 is separated into the oil slurry light component 7 in the oil slurry stripping tower 15, and the oil slurry light component 7 is used as the raw material of the hydrogen treatment device 13 together with the extract oil 3.

[0059] The raffinate 8 from the bottom of the solvent extraction tower 11 flows into the middle and upper part of the raffinate oil stripping tower 16, and the oil slurry heavy component 9 from the oil slurry stripping tower 15 flows into the middle and lower part of the raffinate oil stripping tower 16, the recovered solvent from the top of the raffinate oil stripping tower 16 is supplemented into the solvent 18 stream by heat exchange and condensation; the raffinate 8 and the oil slurry heavy component 9 are mixed in the raffinate oil stripping tower 16 and subjected to solvent recovery, and the mixture stream 10 from the bottom of the raffinate oil stripping tower 16 is used as the raw material of the POX gas making unit 17.

[0060] The endpoints of the ranges and any values in the ranges disclosed herein are not limited to the precise values stated. The ranges and values should be construed to be approximations that allow for significant variation. Various ranges of values that are stated in this disclosure as being preferred, desired, or useful end points can actually be outside the stated range, depending on the context in which the range is being used. It will also be noted that individual value within a range can be further combined with other

[0061] The present application will be further described below in combination with the embodiments, but the content of the present application is not limited to the following embodiments.

[0062] In the Examples and Comparative Examples:

[0063] Low-quality heavy oil A is the vacuum residue obtained from deep vacuum drawing of crude oil produced by Sinopec Gaoqiao Petrochemical Company. Low-quality heavy oil B is the vacuum residue obtained from Sinopec Yanshan Petrochemical Company. The properties of these two vacuum residues are listed in Table 1. Both vacuum residues are low-quality raw materials with high carbon residue, high asphaltene content, and high metal content.

[0064] The residue oil hydrogenation catalyst is produced by the Changling Branch of Sinopec Catalyst Company and its trade name is RHT-200.

[0065] The catalytic cracking catalyst is produced by the Qilu Branch of Sinopec Catalyst Company and its trade name is RICC-1.

[0066] Example 1

[0067] Low-quality heavy oil A and a mixed solvent of n-pentane and n-hexane (containing 70 wt% n-pentane and 30 wt% n-hexane) were separately introduced into a solvent extraction tower for solvent extraction. The solvent was recovered from the extract obtained at the top of the solvent extraction tower to obtain extracted oil. The solvent was removed from the raffinate obtained at the bottom of the solvent extraction tower by steam stripping to obtain raffinate oil. The operating conditions of the solvent extraction unit are shown in Table 2, the properties of the extracted oil are shown in Table 3, and the properties of the raffinate oil are shown in Table 4.

[0068] The extracted oil was introduced into a hydrogenation reactor and, in the presence of hydrogen, contacted with a residue oil hydrogenation catalyst (RHT-200) for hydrogenation. The resulting products were separated into hydrogenated products and hydrogenated tail oil. The residue oil hydrogenation reaction conditions and the distribution of hydrogenated products are listed in Table 5.

[0069] The hydrogenated tail oil is used as a raw material to enter the catalytic cracking unit for treatment. The catalytic cracking catalyst RICC-1 is used. The catalytic cracking reaction conditions are: reaction temperature 580℃, catalyst-oil ratio 10, mass space velocity 4h -1 The water injection rate was 25wt%. The catalytic cracking slurry (properties listed in Table 6) obtained from the catalytic cracking unit was directly fed into the lower middle section of the raffinate stripping column, while the raffinate solution flowing from the bottom of the solvent extraction column was fed into the upper middle section of the raffinate stripping column. After stripping to remove light hydrocarbons, the mixture of the raffinate oil flowing from the bottom of the raffinate stripping column and the catalytic cracking slurry was fed into the POX gasification unit as the feedstock for POX gasification. The mass ratio of the catalytic cracking slurry to the raffinate oil was 4:1, and the properties of the mixed stream are listed in Table 7.

[0070] Example 2

[0071] The poor quality heavy oil B and heptane were introduced into solvent extraction column respectively for solvent extraction. The extract obtained from the top of the solvent extraction column was recovered to obtain extract oil. The raffinate obtained from the bottom of the solvent extraction column was stripped to remove solvent to obtain raffinate oil. The operating conditions of the solvent extraction unit are shown in Table 2, the properties of the extract oil are shown in Table 3, and the properties of the raffinate oil are shown in Table 4.

[0072] The extract oil was introduced into a hydrogenation reactor to contact with a residue oil hydrogenation catalyst RHT-200 in the presence of hydrogen to carry out hydrogenation reaction, and the obtained product was separated into hydrogenation product and hydrogenation tail oil. The residue oil hydrogenation reaction conditions and hydrogenation product distribution are shown in Table 5.

[0073] The hydrogenation tail oil was introduced into a catalytic cracking device as a raw material for treatment, and a catalytic cracking catalyst RICC-1 was used. The catalytic cracking reaction conditions were as follows: the reaction temperature was 580°C, the catalyst to oil ratio was 10, the mass space velocity was 4h -1 , and the water injection amount was 25wt%. The catalytic cracking slurry (the properties are shown in Table 6) obtained from the catalytic cracking device was stripped to remove light hydrocarbons to obtain slurry heavy components. The slurry heavy components were introduced from the middle and lower part of the raffinate stripping column, and the raffinate oil solution flowing out from the bottom of the solvent extraction column was introduced from the middle and upper part of the raffinate stripping column. After stripping to remove light hydrocarbons, the mixture of the raffinate oil flowing out from the bottom of the raffinate stripping column and the catalytic cracking slurry was introduced into a POX gas making unit as a raw material for POX gas making. The mass ratio of the catalytic cracking slurry and the raffinate oil was 3.37:1. The operating conditions of the slurry stripping column and the properties of the mixture flow are shown in Table 7.

[0074] Example 3

[0075] The poor quality heavy oil B and heptane were introduced into solvent extraction column respectively for solvent extraction. The extract obtained from the top of the solvent extraction column was recovered to obtain extract oil. The raffinate obtained from the bottom of the solvent extraction column was stripped to remove solvent to obtain raffinate oil. The operating conditions of the solvent extraction unit are shown in Table 2, the properties of the extract oil are shown in Table 3, and the properties of the raffinate oil are shown in Table 4.

[0076] The extract oil was introduced into a hydrogenation reactor to contact with a residue oil hydrogenation catalyst RHT-200 in the presence of hydrogen to carry out hydrogenation reaction, and the obtained product was separated into hydrogenation product and hydrogenation tail oil. The residue oil hydrogenation reaction conditions and hydrogenation product distribution are shown in Table 5.

[0077] The hydrogenation tail oil was introduced into a catalytic cracking device as a raw material for treatment, and a catalytic cracking catalyst RICC-1 was used. The catalytic cracking reaction conditions were as follows: the reaction temperature was 580°C, the catalyst to oil ratio was 10, the mass space velocity was 4h -1The catalytically cracked oil slurry (properties listed in Table 6) obtained from the catalytic cracking unit was stripped of light hydrocarbons in the slurry stripping column, and the oil slurry heavy component obtained from the slurry stripping column was fed into the middle and lower part of the raffinate stripping column, and the raffinate oil solution from the bottom of the solvent extraction column was fed into the middle and upper part of the raffinate stripping column. After stripping of light hydrocarbons, the mixture of raffinate oil and catalytically cracked oil slurry from the bottom of the raffinate stripping column was fed into the POX gas making unit as raw material for POX gas making. The mass ratio of catalytically cracked oil slurry and raffinate oil was 4.1:1, and the operating conditions of the slurry stripping column and the properties of the mixture stream are listed in Table 7.

[0078] Comparative Example 1

[0079] The poor quality heavy oil A was used as the raw material of the residue hydrogenation unit. RHT-200 was used as the residue hydrogenation catalyst, and the operating conditions of the residue hydrogenation unit and the hydrogenation product distribution are listed in Table 5.

[0080] Compared with the examples, the hydrogenation treatment conditions in the comparative example were more severe (higher reaction temperature and hydrogen partial pressure, and larger hydrogen oil volume ratio), and from the experimental phenomena in the laboratory, there was visible black material on the surface of the catalyst unloaded after the experiment, which was predicted to have a significantly shorter service life than the catalyst when the refined oil obtained by selective separation was used as the raw material.

[0081] Table 1 Properties of poor quality heavy oil

[0082]

[0083] Table 2 Operating conditions of the solvent extraction unit

[0084]

[0085]

[0086] Table 3 Properties of extracted oil

[0087]

[0088] As can be seen from Table 3, the solvent extraction separation of the poor quality heavy oil A in Example 1 obtained the extracted oil with a yield of more than 70wt%, the asphaltene content of the extracted oil was less than 0.1wt%, and the asphaltene removal rate was greater than 99%, which was a high-quality residue hydrogenation raw material.

[0089] The solvent extraction separation of the poor quality heavy oil B in Example 2 obtained the extracted oil with a yield of 80%, the asphaltene content of the extracted oil was 0.3wt%, and the asphaltene removal rate was 96.1wt%, which was a high-quality residue hydrogenation raw material.

[0090] The yield of the extracted oil obtained by solvent extraction separation of the poor quality heavy oil B in Example 3 reached 87%, the asphaltene content of the extracted oil was 0.7 wt%, the asphaltene removal rate thereof was 90.8 wt%, and the extracted oil can still be used as a feedstock for residual oil hydrogenation. Compared with Example 2, the asphaltene in the extracted oil increased by 0.4 percentage points, which is equivalent to an increase of 133% of the asphaltene in the asphaltene oil of Example 2, thereby resulting in an increase of the hydrogen partial pressure, the reaction temperature and the hydrogen oil ratio of the extracted oil during heavy oil hydrogenation reaction, and greatly increasing the severity of heavy oil hydrogenation.

[0091] Table 4 properties of raffinate oil

[0092]

[0093] Table 5 product distribution of residual oil hydrogenation

[0094]

[0095]

[0096] Table 6 properties of catalytic cracking slurry oil

[0097]

[0098] Table 7 process conditions for stripping light hydrocarbons from slurry oil and properties of POX gas making feedstock

[0099] Item Example 1 Example 2 Example 3 Oil slurry stripping light hydrocarbon process conditions: Stripping light hydrocarbon temperature / °C / 340 / Oil slurry light hydrocarbon yield / % / 4.5 / Oil slurry heavy component yield / % / 95.5 / POX gas making feedstock properties Oil slurry / raffinate (mass) 4.0 / 1 3.37 / 1 4.1 / 1 Softening point / °C 103.9 112.0 110.4 Calorific value / (MJ / kg) 40.19 40.22 40.21 Viscosity (270°C) / (mPa.s) 97.5 122.5 170.5

[0100] The combined technology proposed in the present application can fully process poor quality residual oil and realize zero discharge of heavy oil.

[0101] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the technical framework of the present application shall be included in the protection scope of the present application.

Claims

1. A method for processing low-quality heavy oil, characterized in that: The following steps are involved: (1) Low-quality heavy oil is brought into contact with a solvent for solvent extraction, and the obtained extract is recovered by solvent to obtain the extracted oil; the obtained raffinate is stripped to remove the solvent to obtain the raffinate oil; (2) The extracted oil is further separated into gasoline fraction, diesel fraction and hydrogenated tail oil after hydrogenation treatment, wherein the hydrogenated tail oil is used as feed for catalytic cracking unit; (3) The catalytic cracking slurry is introduced into the slurry stripper, and stripping gas is introduced. After stripping, the slurry light hydrocarbon component and the slurry heavy component are obtained. The slurry heavy component is mixed with the raffinate oil as a gasification feedstock and introduced into the POX gasification unit to obtain hydrogen or synthesis gas; the mass ratio of the catalytic cracking slurry to the raffinate oil in the gasification feedstock is 1.5-5:1; The solvent is a mixed solvent of pentane and hexane, which contains 60-90 wt% of pentane and 10-40 wt% of hexane.

2. The method for processing low-quality heavy oil according to claim 1, characterized in that: The light component of the oil slurry is mixed with the extracted oil obtained in step (1) and then subjected to hydrogenation treatment.

3. The method for processing low-quality heavy oil according to claim 1 or 2, characterized in that: The stripping gas is introduced into the slurry stripper for stripping. The operating conditions of the slurry stripper are: a pressure of 0.3MPa to 1.0MPa, and the stripping gas is superheated steam.

4. The method for processing low-quality heavy oil according to claim 3, characterized in that: The pressure of the slurry stripper is 0.4 MPa to 0.8 MPa.

5. The method for processing low-quality heavy oil according to claim 1 or 2, characterized in that: The raffinate liquid and the oil slurry heavy component enter the raffinate oil stripping tower for solvent recovery, and the mixture obtained from the bottom of the raffinate oil stripping tower enters the POX gasification unit as a gasification raw material.

6. The method for processing low-quality heavy oil according to claim 1 or 2, characterized in that: In step (1), the operating temperature of the solvent extraction is 150° C.-265° C., the operating pressure is 1.0 MPa-5.0 MPa, and the mass ratio of the solvent to the feedstock oil is 1.0-5.0:

1.

7. The method for processing low-quality heavy oil according to claim 6, characterized in that: In step (1), the operating temperature of the solvent extraction is 160° C.-255° C., the operating pressure is 2.0 MPa-4.0 MPa, and the mass ratio of the solvent to the feedstock oil is 2.0-4.0:

1.

8. The method for processing low-quality heavy oil according to claim 1 or 2, characterized in that: In step (1), the raffinate liquid is subjected to solvent recovery in a raffinate oil stripping tower, and the operating conditions of the raffinate oil stripping tower are: pressure of 0.1-1.0 MPa and temperature not higher than 320°C.

9. The method for processing low-quality heavy oil according to claim 8, characterized in that: In step (1), the raffinate liquid is subjected to solvent recovery in a raffinate oil stripping tower, and the operating conditions of the raffinate oil stripping tower are: pressure of 0.2-0.8 MPa and temperature not higher than 300°C.

10. The method for processing low-quality heavy oil according to claim 1 or 2, characterized in that: In step (1), the extract is subjected to solvent recovery in a solvent recovery tower, and the operating conditions of the solvent recovery tower are: pressure of 3.0-4.0 MPa and temperature of 200° C.-300° C.

11. The method for processing low-quality heavy oil according to claim 10, characterized in that: In step (1), the operating conditions of the solvent recovery tower are: pressure of 3.2-3.8 MPa, and temperature of 230°C-270°C.

12. The method for processing low-quality heavy oil according to claim 1 or 2, characterized in that: In step (3), the viscosity of the gas-generating raw material at 270°C does not exceed 300 cP.

13. The method for processing low-quality heavy oil according to claim 12, characterized in that: In step (3), the viscosity of the gas-generating raw material at 270°C does not exceed 200 cP.

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