Heavy oil supercritical extraction step separation treatment system and treatment method
阅读说明：本技术 一种重油超临界萃取梯级分离处理系统及处理方法 (Heavy oil supercritical extraction step separation treatment system and treatment method ) 是由 刘哲 昝大鑫 邓宏达 王鑫 吕云飞 于 2020-06-29 设计创作，主要内容包括：本发明涉及一种重油超临界萃取梯级分离处理系统,其包括：进料单元；溶剂混合单元：包括溶剂泵、混合器；梯级超临界萃取分离单元：包括串行设置的一级亚临界萃取分离单元及二级亚临界萃取分离单元及三级超临界萃取分离单元,所述溶剂泵的另一路连接至一级亚临界萃取分离单元,一级亚临界萃取分离单元的萃取相出口连接至二级亚临界萃取分离单元的进料口,二级亚临界萃取分离单元的萃取相出口连接至三级超临界萃取分离单元的进料口；溶剂回收单元。本发明的重油超临界萃取梯级分离处理系统及处理方法,可产出三种产品,大大增加了装置的弹性和经济性,加工能力增大,同时运行稳定,能耗低。(The invention relates to a heavy oil supercritical extraction step separation treatment system, which comprises: a feed unit; a solvent mixing unit: comprises a solvent pump and a mixer; a step supercritical extraction separation unit: the device comprises a first-stage subcritical extraction separation unit, a second-stage subcritical extraction separation unit and a third-stage supercritical extraction separation unit which are arranged in series, wherein the other path of a solvent pump is connected to the first-stage subcritical extraction separation unit, an extraction phase outlet of the first-stage subcritical extraction separation unit is connected to a feeding hole of the second-stage subcritical extraction separation unit, and an extraction phase outlet of the second-stage subcritical extraction separation unit is connected to a feeding hole of the third-stage supercritical extraction separation unit; a solvent recovery unit. The heavy oil supercritical extraction cascade separation treatment system and the treatment method can produce three products, greatly increase the elasticity and the economical efficiency of the device, increase the processing capacity, and simultaneously have stable operation and low energy consumption.)
1. A heavy oil supercritical extraction step separation processing system is characterized in that: the method comprises the following steps:
a feeding unit: comprises a feeding buffer tank and a raw material pump;
a solvent mixing unit: the device comprises a solvent pump and a mixer, wherein one path of the solvent pump and a raw material pump are connected to the mixer, and the other path of the solvent pump is connected to a step supercritical extraction separation unit;
a step supercritical extraction separation unit: the device comprises a first-stage subcritical extraction separation unit, a second-stage subcritical extraction separation unit and a third-stage supercritical extraction separation unit which are arranged in series, wherein the other path of a solvent pump is connected to the first-stage subcritical extraction separation unit, an extraction phase outlet of the first-stage subcritical extraction separation unit is connected to a feeding hole of the second-stage subcritical extraction separation unit, and an extraction phase outlet of the second-stage subcritical extraction separation unit is connected to a feeding hole of the third-stage supercritical extraction separation unit;
A solvent recovery unit: and the extraction solvent outlets of the first-stage subcritical extraction separation unit, the second-stage subcritical extraction separation unit and the third-stage supercritical extraction separation unit are connected to the solvent mixing unit through the solvent recovery unit.
2. The heavy oil supercritical fluid extraction step separation processing system according to claim 1, characterized in that: the first-stage subcritical extraction separation unit comprises an asphalt separation tower, a first heat exchanger, a first heater, a third heater, an asphalt flash tank and an asphalt stripping tower, the second-stage subcritical extraction separation unit comprises a heavy deoiling separation tower, a second heat exchanger, a second heater, a fourth heater, a heavy deoiling flash tank and a heavy deoiling stripping tower, and the third-stage supercritical extraction separation unit comprises a deasphalted oil separation tower deasphalted oil flash tank, a fifth heater and a deasphalted oil stripping tower; the bottom raffinate phase outlet of the asphalt separation tower is connected to an asphalt stripping tower through a third heater and an asphalt flash tank, the top extract phase outlet of the asphalt separation tower is connected to a heavy deoiling separation tower through a first heat exchanger and the first heater, the bottom raffinate phase of the heavy deoiling separation tower is connected to the heavy deoiling stripping tower through a fourth heater and the heavy deoiling flash tank, the top extract phase outlet of the heavy deoiling separation tower is connected to the deasphalting separation tower through a second heat exchanger and the second heater, the bottom raffinate phase outlet of the deasphalted oil separation tower is connected to the deasphalted oil stripping tower through a stripper oil flash tank and a fifth heater, and the top solvent outlet of the deasphalted oil separation tower is connected to a solvent pump through a third cooler.
3. The heavy oil supercritical fluid extraction step separation processing system according to claim 1, characterized in that: the solvent recovery unit includes first cooler, second cooler, solvent buffer tank, solvent compressor, recovery solvent jar, recovery solvent pump, the top solvent outlet of pitch flash tank, heavy deoiling flash tank, deasphalted oil flash tank joins the back and is connected to the recovery solvent pump through first cooler, the top solvent outlet of pitch stripper, heavy deoiling stripper, deasphalted oil stripper joins the back and is connected to first cooler through second cooling, solvent buffer tank, solvent compressor, and first cooler is connected to the solvent pump through recovery solvent jar, recovery solvent pump.
4. A heavy oil supercritical extraction step separation processing method is characterized in that: the method comprises the following steps:
1) feeding: a raw material pump sucks heavy oil from a feeding buffer tank, the heavy oil and an extraction solvent from a solvent pump are mixed and pressurized by a mixer, and the mixture is sent to an asphalt separation tower of a first-stage subcritical extraction separation unit;
2) first-stage subcritical extraction: performing subcritical extraction on an extraction solvent and heavy oil in an asphalt separation tower under a subcritical condition, wherein the volume ratio of the total extraction solvent to the heavy oil is 6-10:1, discharging an extraction phase from the top of the asphalt separation tower, wherein the extraction phase comprises heavy deoiled oil, deasphalted oil and the extraction solvent, heating raffinate at the bottom of the asphalt separation tower by a third heater, then feeding the raffinate into an asphalt flash tank to recover the extraction solvent, feeding the material at the bottom of the asphalt flash tank into an asphalt stripping tower to recover the extraction solvent, and discharging an asphalt product from the bottom of the asphalt stripping tower;
3) Secondary subcritical extraction: heating an extract phase at the top of the asphalt separation tower by a first heat exchanger and a first heater, then feeding the extract phase into a heavy deoiling separation tower, carrying out secondary subcritical extraction in the heavy deoiling separation tower, heating a raffinate phase at the bottom of the heavy deoiling separation tower by a fourth heater, then feeding the raffinate phase into an asphalt flash tank to recover an extraction solvent, feeding a material at the bottom of the asphalt flash tank into a heavy deoiling stripping tower to recover the extraction solvent, and discharging a heavy deoiled product at the bottom of the heavy deoiling stripping tower;
4) supercritical solvent separation: heating a top extraction phase of the heavy deasphalted oil separation tower through a second heat exchanger and a second heater, connecting the top extraction phase to a deasphalted oil separation tower, performing supercritical extraction in the deasphalted oil separation tower, recovering an extraction solvent from a bottom raffinate phase of the deasphalted oil separation tower through a deasphalted oil flash tank, and further recovering the extraction solvent from a material at the bottom of the deasphalted oil flash tank in a deasphalted oil stripping tower;
5) solvent circulation: the recovered extraction solvents of the asphalt stripping tower, the heavy deoiling stripping tower and the deasphalted oil stripping tower are collected and then are conveyed back to the solvent pump through a solvent recovery unit; and the extraction solvents recovered by the asphalt flash tank, the heavy deoiling flash tank and the deasphalted oil flash tank are collected and then are conveyed back to the solvent pump through the solvent recovery unit.
5. The heavy oil supercritical fluid extraction step separation processing method according to claim 4, characterized in that: the solvent ratio and the operation temperature of the first-stage subcritical extraction separation unit, the second-stage subcritical extraction separation unit and the third-stage supercritical extraction separation unit are adjusted according to the product requirements; the operation condition of the asphalt separation tower is 4-5Mpag, 60-110 ℃; the operation condition of the heavy deoiling and separating tower is 4-5Mpag and 60-160 ℃; the operating conditions of the deasphalted oil separation tower are 4-5Mpag and 100-180 ℃.
6. The heavy oil supercritical fluid extraction step separation processing method according to claim 4, characterized in that: exchanging heat between the extract phase of the asphalt separation tower in the step 2) and an extraction solvent at the top of the deasphalted oil separation tower in a first heat exchanger, and heating; and 3) exchanging heat between the extract phase of the heavy deoiling and separating tower in the second heat exchanger and the extraction solvent at the top of the deasphalted oil separating tower to raise the temperature.
7. The heavy oil supercritical fluid extraction step separation processing method according to claim 4, characterized in that: the extraction solvent is C3To C5One or a mixture of two or more of alkanes.
8. The heavy oil supercritical fluid extraction step separation processing method according to claim 4, characterized in that: the extraction solvent is C 3A mixed solvent of alkane and isobutane, a mixed solvent of normal butane and isobutane, or a mixed solvent of isobutane and isopentane.
9. The heavy oil supercritical fluid extraction step separation processing method according to claim 4, characterized in that: the heavy oil is atmospheric residue, vacuum residue, atmospheric residue-vacuum residue mixture or catalytic slurry oil.
Technical Field
The invention belongs to the technical field of supercritical extraction, and particularly relates to a gradient separation treatment system and a treatment method for heavy oil supercritical extraction.
Background
The solvent separation process is to treat liquid or liquid-solid mixture with a proper solvent, and to dissolve the component to be separated in the mixture into the solvent by utilizing the characteristics of different solubility of each component in the solvent and the similar intermiscibility principle, thereby achieving the purpose of separating the component from other components.
The solvent separation process is an important process in the oil refining and chemical industries, and is widely applied to the oil refining industry. For example, solvent deasphalting for obtaining a lubricant oil feedstock and a catalytic cracking feedstock from heavy oil, solvent refining and solvent dewaxing for producing a lubricant oil, and aromatic extraction for extracting aromatic hydrocarbons from a reformate or a catalytic cracking cycle oil are all solvent separation processes.
In the oil refining industry, the solvent deasphalting process is mainly used for preparing high-viscosity lube base oil and catalytic cracking raw oil from vacuum residue, and the deasphalted asphalt can be used for producing road asphalt under the condition of proper raw material. Among other things, the primary role of the solvent deasphalting process is to remove the bitumen from the heavy oil to obtain a deasphalted oil with a lower carbon residue value and to improve color. The vacuum residue is added into catalytic cracking raw material gas oil to be an important way for improving the yield of light oil, but many vacuum residues contain more metals and substances which are easy to generate coke, and are not easy to be directly added into the catalytic cracking raw material, and most of the metals and the substances which are easy to generate coke can be removed through solvent deasphalting, so that the quality of the heavy oil catalytic cracking feed is obviously improved.
Conventional solvent deasphalting processes operate at temperature and pressure conditions below the critical point of the solvent. The process uses a large amount of solvent, the solvent ratio adopted is generally 3-5 (mass ratio), and the solvent must be recovered and recycled. The investment and operating costs of the solvent recovery section have a significant impact on the overall plant economics. Of the amount of solvent to be recovered, about 90% comes from the extract (deasphalted oil phase) and the rest from the raffinate (deasphalted oil phase). Therefore, the important point of solvent recovery is to recover the solvent in the extract. In recent years, research and technical development have been greatly advanced on supercritical solvent extraction and supercritical solvent recovery which are operated under temperature and pressure conditions not lower than the critical point of the solvent. Compared with the traditional solvent deasphalting technology, the supercritical extraction technology has qualitative leap in the aspects of energy consumption, operation reliability and the like.
The traditional solvent deasphalting technology is two products, namely asphalt product and deasphalted oil product. The requirements of producing a plurality of products according to different compositions cannot be met. For example, in the production of needle coke, catalytic slurry oil is used as a feed, and aromatic-rich oil, asphalt and alkane-rich oil need to be separated, so that a three-product scheme is required. The traditional solvent deasphalting can not meet the requirement.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a step separation treatment system for heavy oil supercritical extraction, which can produce multi-stage products according to composition distribution, simplify flow operation, reduce energy consumption and improve the online rate and reliability of the device.
The invention also aims to provide a heavy oil supercritical extraction step separation treatment method.
The technical problem to be solved by the invention is realized by the following technical scheme:
a heavy oil supercritical extraction step separation processing system comprises:
a feeding unit: comprises a feeding buffer tank and a raw material pump;
a solvent mixing unit: the device comprises a solvent pump and a mixer, wherein one path of the solvent pump and a raw material pump are connected to the mixer, and the other path of the solvent pump is connected to a step supercritical extraction separation unit;
a step supercritical extraction separation unit: the device comprises a first-stage subcritical extraction separation unit, a second-stage subcritical extraction separation unit and a third-stage supercritical extraction separation unit which are arranged in series, wherein the other path of a solvent pump is connected to the first-stage subcritical extraction separation unit, an extraction phase outlet of the first-stage subcritical extraction separation unit is connected to a feeding hole of the second-stage subcritical extraction separation unit, and an extraction phase outlet of the second-stage subcritical extraction separation unit is connected to a feeding hole of the third-stage supercritical extraction separation unit;
A solvent recovery unit: and the extraction solvent outlets of the first-stage subcritical extraction separation unit, the second-stage subcritical extraction separation unit and the third-stage supercritical extraction separation unit are connected to the solvent mixing unit through the solvent recovery unit.
The first-stage subcritical extraction separation unit comprises an asphalt separation tower, a first heat exchanger, a first heater, a third heater, an asphalt flash tank and an asphalt stripping tower, the second-stage subcritical extraction separation unit comprises a heavy deoiling separation tower, a second heat exchanger, a second heater, a fourth heater, a heavy deoiling flash tank and a heavy deoiling stripping tower, and the third-stage supercritical extraction separation unit comprises a deasphalted oil separation tower deasphalted oil flash tank, a fifth heater and a deasphalted oil stripping tower; the bottom raffinate phase outlet of the asphalt separation tower is connected to an asphalt stripping tower through a third heater and an asphalt flash tank, the top extract phase outlet of the asphalt separation tower is connected to a heavy deoiling separation tower through a first heat exchanger and the first heater, the bottom raffinate phase of the heavy deoiling separation tower is connected to the heavy deoiling stripping tower through a fourth heater and the heavy deoiling flash tank, the top extract phase outlet of the heavy deoiling separation tower is connected to the deasphalting separation tower through a second heat exchanger and the second heater, the bottom raffinate phase outlet of the deasphalted oil separation tower is connected to the deasphalted oil stripping tower through a stripper oil flash tank and a fifth heater, and the top solvent outlet of the deasphalted oil separation tower is connected to a solvent pump through a third cooler.
Moreover, the solvent recovery unit includes first cooler, second cooler, solvent buffer tank, solvent compressor, recovery solvent jar, recovery solvent pump, the top solvent export of pitch flash tank, heavy deoiling flash tank, deasphalted oil flash tank joins the back and is connected to the recovery solvent pump through first cooler, pitch stripper, heavy deoiling stripper, the top solvent export of deasphalted oil stripper join the back and be connected to first cooler through second cooling, solvent buffer tank, solvent compressor, first cooler is connected to the solvent pump through recovery solvent jar, recovery solvent pump.
A heavy oil supercritical extraction step separation treatment method comprises the following steps:
1) feeding: a raw material pump sucks heavy oil from a feeding buffer tank, the heavy oil and an extraction solvent from a solvent pump are mixed and pressurized by a mixer, and the mixture is sent to an asphalt separation tower of a first-stage subcritical extraction separation unit;
2) first-stage subcritical extraction: performing subcritical extraction on an extraction solvent and heavy oil in an asphalt separation tower under a subcritical condition, wherein the volume ratio of the total extraction solvent to the heavy oil is 6-10:1, discharging an extraction phase from the top of the asphalt separation tower, wherein the extraction phase comprises heavy deoiled oil, deasphalted oil and the extraction solvent, heating raffinate at the bottom of the asphalt separation tower by a third heater, then feeding the raffinate into an asphalt flash tank to recover the extraction solvent, feeding the material at the bottom of the asphalt flash tank into an asphalt stripping tower to recover the extraction solvent, and discharging an asphalt product from the bottom of the asphalt stripping tower;
3) Secondary subcritical extraction: heating an extract phase at the top of the asphalt separation tower by a first heat exchanger and a first heater, then feeding the extract phase into a heavy deoiling separation tower, carrying out secondary subcritical extraction in the heavy deoiling separation tower, heating a raffinate phase at the bottom of the heavy deoiling separation tower by a fourth heater, then feeding the raffinate phase into an asphalt flash tank to recover an extraction solvent, feeding a material at the bottom of the asphalt flash tank into a heavy deoiling stripping tower to recover the extraction solvent, and discharging a heavy deoiled product at the bottom of the heavy deoiling stripping tower;
4) supercritical solvent separation: heating a top extraction phase of the heavy deasphalted oil separation tower through a second heat exchanger and a second heater, connecting the top extraction phase to a deasphalted oil separation tower, performing supercritical extraction in the deasphalted oil separation tower, recovering an extraction solvent from a bottom raffinate phase of the deasphalted oil separation tower through a deasphalted oil flash tank, and further recovering the extraction solvent from a material at the bottom of the deasphalted oil flash tank in a deasphalted oil stripping tower;
5) solvent circulation: the recovered extraction solvents of the asphalt stripping tower, the heavy deoiling stripping tower and the deasphalted oil stripping tower are collected and then are conveyed back to the solvent pump through a solvent recovery unit; and the extraction solvents recovered by the asphalt flash tank, the heavy deoiling flash tank and the deasphalted oil flash tank are collected and then are conveyed back to the solvent pump through the solvent recovery unit.
Moreover, the solvent ratio and the operation temperature of the first-stage subcritical extraction separation unit, the second-stage subcritical extraction separation unit and the third-stage supercritical extraction separation unit are adjusted according to the product requirements; the operation condition of the asphalt separation tower is 4-5Mpag, 60-110 ℃; the operation condition of the heavy deoiling and separating tower is 4-5Mpag and 60-160 ℃; the operating conditions of the deasphalted oil separation tower are 4-5Mpag and 100-180 ℃.
In addition, the extract phase of the asphalt separation tower in the step 2) exchanges heat with the extraction solvent at the top of the deasphalted oil separation tower in a first heat exchanger and is heated; and 3) exchanging heat between the extract phase of the heavy deoiling and separating tower in the second heat exchanger and the extraction solvent at the top of the deasphalted oil separating tower to raise the temperature.
And, the extraction solvent is C3To C5One or a mixture of two or more of alkanes.
And, the extraction solvent is C3A mixed solvent of alkane and isobutane, a mixed solvent of normal butane and isobutane, or a mixed solvent of isobutane and isopentane.
And, the heavy oil is atmospheric residue, vacuum residue, atmospheric residue-vacuum residue mixture, or catalytic slurry oil.
The invention has the advantages and beneficial effects that:
1. the invention discloses a heavy oil supercritical extraction cascade separation treatment system, which comprises a feeding unit, a solvent mixing unit and a cascade supercritical extraction separation unit: the device comprises a first-stage subcritical extraction separation unit, a second-stage subcritical extraction separation unit and a third-stage supercritical extraction separation unit which are arranged in series, wherein the first-stage subcritical extraction separation unit and the second-stage subcritical extraction separation unit extract heavy oil under a subcritical condition, and then the third-stage supercritical extraction separation unit recovers solvent under a supercritical condition, so that the device energy consumption is greatly reduced, the flow operation is simplified, the online rate and the reliability of the device are improved, the investment and the device floor area are reduced, and high-quality feeding is provided for downstream process devices.
2. The heavy oil supercritical extraction step separation treatment system reduces the energy consumption of the device by sharing a solvent system, and is very favorable for ensuring the stability of the device.
3. The heavy oil supercritical extraction cascade separation treatment method of the invention realizes the purpose of producing products with different specifications by adjusting the operation conditions of the cascade supercritical extraction separation unit, namely the solvent ratio and the operation temperature, for example, the temperature of the top of each corresponding asphalt separation tower is respectively controlled by each solvent cooler, thereby controlling the yield of each heavy deoiled oil and deasphalted oil.
4. The heavy oil supercritical extraction cascade separation treatment system and the treatment method can produce three products, greatly increase the elasticity and the economical efficiency of the device, increase the processing capacity, and simultaneously have stable operation and low energy consumption.
Drawings
FIG. 1 is a flow chart of the system of the present invention.
Reference numerals:
1-feeding buffer tank, 2-raw material pump, 3-solvent pump, 4-mixer, 5-asphalt separating tower, 6-third heater, 7-asphalt flash tank, 8-asphalt stripping tower, 9-third cooler, 10-first heat exchanger, 11-first heater, 12-heavy deoiling and separating tower, 13-fourth heater, 14-heavy deoiling flash tank, 15-heavy deoiling and stripping tower, 16-deasphalted oil separating tower, 17-deasphalted oil flash tank, 18-fifth heater, 19-deasphalted oil stripping tower, 20-second cooler, 21-solvent buffer tank, 22-solvent compressor, 23-second heat exchanger, 24-second heater, 25-first cooler, 26-recovery solvent tank, 27-recycle solvent pump.
Detailed Description
The present invention is further illustrated by the following specific examples, which are intended to be illustrative, not limiting and are not intended to limit the scope of the invention.
A heavy oil supercritical extraction step separation processing system comprises:
a feeding unit: the device comprises a feeding buffer tank 1 and a raw material pump 2, wherein heavy oil in the feeding buffer tank is mixed with an extraction solvent by a mixer and then enters a step supercritical extraction separation unit by a raw material part;
a solvent mixing unit: the device comprises a solvent pump 3 and a mixer 4, wherein one path of the solvent pump and a raw material pump are connected to the mixer, and the other path of the solvent pump is connected to a step supercritical extraction separation unit;
a step supercritical extraction separation unit: the device comprises a first-stage subcritical extraction separation unit, a second-stage subcritical extraction separation unit and a third-stage supercritical extraction separation unit which are arranged in series, wherein the other path of a solvent pump is connected to the first-stage subcritical extraction separation unit, an extraction phase outlet of the first-stage subcritical extraction separation unit is connected to a feeding hole of the second-stage subcritical extraction separation unit, and an extraction phase outlet of the second-stage subcritical extraction separation unit is connected to a feeding hole of the third-stage supercritical extraction separation unit;
The first-stage subcritical extraction separation unit comprises an
A solvent recovery unit: the extraction solvent outlets of the first-stage subcritical extraction separation unit, the second-stage subcritical extraction separation unit and the third-stage supercritical extraction separation unit are connected to the solvent mixing unit through the solvent recovery unit. The concrete structure is as follows: the solvent recovery unit comprises a
A heavy oil supercritical extraction step separation treatment method comprises the following steps:
1) feeding: a raw material pump sucks heavy oil from a feeding buffer tank, the heavy oil and an extraction solvent from a solvent pump are mixed and pressurized by a mixer, and the mixture is sent to an asphalt separation tower of a first-stage subcritical extraction separation unit; the heavy oil is atmospheric residue, vacuum residue, atmospheric residue-vacuum residue mixture or catalytic slurry oil.
2) First-stage subcritical extraction: performing subcritical extraction on an extraction solvent and heavy oil in an asphalt separation tower under a subcritical condition, wherein the volume ratio of the total extraction solvent to the heavy oil is 6-10:1, discharging an extraction phase from the top of the asphalt separation tower, wherein the extraction phase comprises heavy deoiled oil, deasphalted oil and the extraction solvent, heating raffinate at the bottom of the asphalt separation tower by a third heater, then feeding the raffinate into an asphalt flash tank to recover the extraction solvent, feeding the material at the bottom of the asphalt flash tank into an asphalt stripping tower to recover the extraction solvent, and discharging an asphalt product from the bottom of the asphalt stripping tower; the extraction phase of the asphalt separation tower exchanges heat with an extraction solvent which leaves the top of the deasphalted oil separation tower and is heated in a first heat exchanger;
3) secondary subcritical extraction: heating an extract phase at the top of the asphalt separation tower by a first heat exchanger and a first heater, then feeding the extract phase into a heavy deoiling separation tower, carrying out secondary subcritical extraction in the heavy deoiling separation tower, heating a raffinate phase at the bottom of the heavy deoiling separation tower by a fourth heater, then feeding the raffinate phase into an asphalt flash tank to recover an extraction solvent, feeding a material at the bottom of the asphalt flash tank into a heavy deoiling stripping tower to recover the extraction solvent, and discharging a heavy deoiled product at the bottom of the heavy deoiling stripping tower; and exchanging heat between the extract phase of the heavy deoiling and separating tower and the extraction solvent at the top of the deasphalted oil separating tower in a second heat exchanger to raise the temperature.
4) Supercritical solvent separation: heating the top extract phase of the heavy-duty de-oiling separation tower through a second heat exchanger and a second heater, connecting the top extract phase to a de-asphalted oil separation tower, performing supercritical extraction in the de-asphalted oil separation tower, recovering an extraction solvent from the bottom raffinate phase of the de-asphalted oil separation tower through a de-asphalted oil flash drum, and further recovering the extraction solvent from the material at the bottom of the de-asphalted oil flash drum in a de-asphalted oil stripping tower;
5) solvent circulation: the recovered extraction solvents of the asphalt stripping tower, the heavy deoiling stripping tower and the deasphalted oil stripping tower are collected and then are conveyed back to the solvent pump through a solvent recovery unit; and the extraction solvents recovered by the asphalt flash tank, the heavy deoiling flash tank and the deasphalted oil flash tank are collected and then are conveyed back to the solvent pump through the solvent recovery unit.
The solvent ratio and the operation temperature of the first-stage subcritical extraction separation unit, the second-stage subcritical extraction separation unit and the third-stage supercritical extraction separation unit are adjusted according to the product requirements.
The extraction solvent is C3To C5One or a mixture of two or more of alkanes. The extraction solvent is C3A mixed solvent of alkane and isobutane, a mixed solvent of normal butane and isobutane, or a mixed solvent of isobutane and isopentane.
The process parameters of the treatment method are illustrated as follows:
1. the supercritical heavy oil treatment of the present invention is carried out in a system as shown in fig. 1. The extraction solvent was propane. The volume ratio of the total extraction solvent to the heavy oil entering the asphalt separation tower is 6: 1; wherein the operation condition of the asphalt separation tower is 4-5Mpag and 60-70 ℃; the operation condition of the heavy deoiling and separating tower is 4-5Mpag, and the operation condition of the deasphalted oil separating tower at the temperature of 60-80 ℃ is 4-5Mpag and 100-120 ℃. The yields and physical properties of the resulting asphalt product, gum product and deasphalted oil product after treatment with the above system are shown in table 1.
TABLE 1
The deasphalted oil of this example was used as feed for downstream lubricating oil units, the deasphalted oil was used as feed for catalytic cracking units, the pitch was sold as product, the gum was used as a conditioner for adjusting the product grade of the various pitches, and the solvent used was propane (C3). Therefore, the technology of the invention can obviously reduce the content of the Kancki carbon residue and the content of the metal nickel and vanadium in the deasphalted oil, greatly improve the quality of the deasphalted oil, and realize multi-stage separation, wherein the colloid can be flexibly used for adjusting the grade of the asphalt.
2. The supercritical heavy oil treatment of the present example was carried out in the system shown in fig. 1. The extraction solvent was isobutane. The volume ratio of the total extraction solvent to the heavy oil entering the asphalt separation tower is 8: 1; wherein the operation condition of the asphalt separation tower is 4-5Mpag and 90-110 ℃; the operation condition of the heavy deoiling and separating tower is 4-5Mpag, and the operation condition of the deasphalted oil separating tower at the temperature of 130-150 ℃ is 4-5Mpag and 165 ℃ at the temperature of 150 ℃. The yields and physical properties of the resulting asphalt product, gum product and deasphalted oil product after treatment with the above system are shown in table 2.
TABLE 2
The deasphalted oil of this example can be used as the feedstock for lubricating oil base oil units, bitumen can be sold as a product, gum can be used as a conditioner for adjusting the product grades of different bitumens, and the solvent used is isobutane (I-C4). Therefore, the technology of the invention can obviously reduce the content of the Kancki carbon residue and the content of the metal nickel and vanadium in the deasphalted oil, greatly improve the quality of the deasphalted oil, and realize multi-stage separation, wherein the colloid can be flexibly used for adjusting the grade of the asphalt.
3. The supercritical heavy oil treatment of the present invention is carried out in a system as shown in fig. 1. The extraction solvent is n-butane. The volume ratio of the total extraction solvent to the heavy oil entering the asphalt separation tower is 10: 1; wherein the operation condition of the asphalt separation tower is 4-5Mpag, 100-110 ℃; the operation condition of the heavy deoiling and separating tower is 4-5Mpag, and the operation condition of the 130-160 ℃ deasphalted oil separating tower is 4-5Mpag and 160-180 ℃. The yields and physical properties of the resulting asphalt product, gum product and deasphalted oil product after treatment with the above system are shown in table 3.
TABLE 3
The deasphalted oil of this example can be used as the feedstock for lubricating oil base oil units, bitumen can be sold as a product, gum can be used as a conditioner for adjusting the product grades of different bitumens, and the solvent used is isobutane (N-C4). Therefore, the technology of the invention can realize multi-stage separation, wherein the colloid can be flexibly used for adjusting the grade of the asphalt.
Although the embodiments of the present invention and the accompanying drawings have been disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, alterations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and thus the scope of the invention is not limited to the embodiments and drawings disclosed.
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