CN111808629A

CN111808629A - Oily residue treatment system and method

Info

Publication number: CN111808629A
Application number: CN202010586485.2A
Authority: CN
Inventors: 昝大鑫; 王鑫
Original assignee: Zhangjiagang Free Trade Zone Huixin Chemical Technology Co ltd
Current assignee: Zhangjiagang Free Trade Zone Huixin Chemical Technology Co ltd
Priority date: 2020-06-24
Filing date: 2020-06-24
Publication date: 2020-10-23

Abstract

The application discloses an oily residue treatment system and method, and relates to the technical field of recovery treatment of solid-containing dirty oil. The oily residue treatment system comprises an extraction module, and the extraction module is provided with a first separation tower and a second separation tower. This application carries out extraction under the subcritical state through setting up a pair of oily residue of knockout tower, and the rethread sets up the mixed solution of knockout tower two pairs of deasphalted oil and extraction solvent and carries out the separation under the supercritical state, has improved the drawback that current traditional solvent deasphalting technique energy consumption is high, simplifies the flow operation, reduces by a wide margin and contains solid residue handling capacity, but the deasphalted oil cyclic utilization of extraction, the income is improved. And moreover, the softening point of the residue is improved, and the problem of difficult curing is thoroughly solved.

Description

Oily residue treatment system and method

Technical Field

The application relates to the technical field of recovery and treatment of solid-containing dirty oil, in particular to a system and a method for treating oily residues.

Background

The solvent separation process is to treat the liquid-solid mixture with a proper solvent, and to make the components to be separated in the heavy oil dissolve in the solvent by utilizing the characteristics of different solubility of the components of the heavy oil in the solvent and the principle of similar intermiscibility, thereby achieving the purpose of separating the components from other components.

The extraction and separation process is an important process in oil refining and chemical industry, and is widely applied to the oil refining industry. For example, solvent deasphalting for obtaining a lube oil feedstock and a catalytic cracking feedstock from a residual oil, solvent refining and solvent dewaxing for producing lube oils, aromatic extraction for extracting aromatic hydrocarbons from a reformate or a catalytic cracking cycle oil, and the like are all extraction separation processes.

In the oil refining industry, the treatment difficulty is high for oil-solid mixed materials. For example, the residue of the slurry bed hydrogenation process contains a small amount of wax oil, unconverted heavy oil, and solids such as additives and catalysts, and has high viscosity, high carbon residue, and very high heavy metal content, which is difficult to handle. Generally, the solid fuel can be solidified only after reaching a softening point through temperature reduction, and can be transported as the solid fuel after being crushed. However, if the light oil component remains in the residue in a large amount, for example, a wax oil or a diesel oil component, the softening point of the residue is very low and the residue cannot be solidified and transported at normal temperature. Meanwhile, the heavy metal, sulfur and other impurities are contained in the waste water, so that the treatment difficulty is high.

For example, the chinese patent publication No. CN101165139B discloses a method for preparing water slurry from granulated asphalt of petroleum and coal asphalt residues, in which a raw material with a low softening point is premixed with an extraction solvent, and then a deasphalted oil phase and a deasphalted asphalt phase are extracted and separated, and the asphalt is fed into a granulation tower for granulation. In the technical scheme, a large amount of extraction solvent in the deasphalted oil is not recycled, so that the resource waste of the deasphalted oil and the extraction solvent is caused, but a large amount of energy is consumed for completely separating the deasphalted oil and the extraction solvent.

Disclosure of Invention

The application aims to provide an oil-containing residue treatment system and method, which can greatly overcome the defect of high energy consumption of the traditional extraction technology while treating residues, simplify the flow operation through the supercritical separation technology and improve the online rate and reliability of the device.

In order to achieve the above purpose, the embodiments of the present application adopt the following technical solutions: an oil-containing residue processing system comprising: a feed buffer tank for storing the oil-containing residue; the extraction module, this extraction module is connected with the feeding buffer tank, and the extraction module has: the first separation tower is connected with the feeding buffer tank, and oil-containing residues are fed into the first separation tower; a solvent pump connected to the separation column to mix the extraction solvent with the oily residue to obtain an extract phase and a raffinate phase; the second separation tower is connected with the top of the first separation tower, the extract phase is sent to the second separation tower, and the top of the second separation tower is connected with a solvent pump through a pipeline; wherein the operation pressure of the first separation tower is higher than the critical pressure of the extraction solvent, and the operation temperature of the first separation tower is lower than the critical temperature of the extraction solvent; the operation pressure of the second separation tower is higher than the critical pressure of the extraction solvent, and the operation temperature of the second separation tower is higher than the critical temperature of the extraction solvent.

In the technical scheme, the separation tower is arranged to extract the oil-containing residues in the subcritical state, and then the separation tower is arranged to separate the deasphalted oil and the extraction solvent in the supercritical state from the mixed solution of the deasphalted oil and the extraction solvent, so that the defect of high energy consumption of the traditional solvent deasphalting technology is overcome, the flow operation is simplified, the solid-containing residue treatment capacity is greatly reduced, the extracted deasphalted oil can be recycled, and the benefit is improved. In addition, the method improves the softening point of the residue, and thoroughly solves the problem that the oil-containing residue in the prior art is difficult to solidify.

Further, according to the embodiment of the application, a feeding pump is arranged between the feeding buffer tank and the first separation tower.

Further, according to the embodiment of the application, the extraction module further comprises a first heater, and the first heater is arranged on a communication pipeline between the first separation tower and the second separation tower.

Further, according to the embodiment of the present application, wherein the extraction module further includes a heat exchanger, the heat exchanger is disposed at an intersection of the extract phase output pipeline of the first separation tower and the tower top output pipeline of the second separation tower.

Further, according to the embodiment of the application, the extraction module further comprises a third cooler, and the third cooler is arranged on a communication pipeline between the second separation tower and the solvent pump.

Further, according to the embodiment of the present application, wherein, the oily residue processing system further comprises: the asphalt extraction module is connected with the bottom of the first separation tower and is used for separating asphalt and an extraction solvent; the deasphalted oil extraction module is connected with the bottom of the second separation tower by the extraction module and is used for separating the deasphalted oil from the extraction solvent; and the solvent recovery module is respectively communicated with the asphalt extraction module and the deasphalted oil extraction module through pipelines, and is used for collecting the extraction solvent separated by the asphalt extraction module and the deasphalted oil extraction module.

Further, according to an embodiment of the present application, wherein the asphalt extraction module includes: the first flash tank is connected with the bottom of the first separation tower through a pipeline; and the first stripping tower is connected with the bottom of the first flash tank through a pipeline.

Further, according to the embodiment of the application, the asphalt extraction module further comprises a second heater, and the second heater is arranged on a communication pipeline between the first separation tower and the first flash tank.

Further, according to the embodiment of the application, the asphalt extraction module further comprises a third heater, and the third heater is arranged on a communication pipeline between the first flash tank and the first stripping tower.

Further, according to an embodiment of the present application, wherein the deasphalted oil extraction module comprises: the second flash tank is connected with the bottom of the second separation tower through a pipeline; and the second stripping tower is connected with the bottom of the second flash tank through a pipeline.

Further, according to the embodiment of the application, the deasphalted oil extraction module further comprises a fourth heater, and the fourth heater is arranged on a communication pipeline between the second separation tower and the second flash tank.

Further, according to the embodiment of the application, the deasphalted oil extraction module further comprises a heater five, and the heater five is arranged on a communication pipeline between the flash tank II and the stripping tower II.

Further, according to the embodiment of the present application, wherein the solvent recovery module comprises a recovery tank, and the recovery tank is used for intensively storing the extraction solvent separated by the asphalt extraction module and the deasphalted oil module.

Further, according to an embodiment of the present application, wherein the recovery tank is in communication with the solvent pump.

In order to achieve the above object, an embodiment of the present application further discloses an oil-containing residue treatment method, including the following steps:

and (3) extraction: mixing the oily residue to be treated with an extraction solvent in a subcritical state of the extraction solvent, wherein the volume ratio of the amount of the extraction solvent to the amount of the fed oily residue is 7-9:1, separating asphalt and solids in the oily residue from the extraction solvent, and obtaining products of an asphalt/solid-solvent mixture and a deasphalted oil and solvent mixture;

separation: separating the deasphalted oil from the solvent mixture in the supercritical state of the extraction solvent, and recovering the extraction solvent.

Further, according to an embodiment of the present application, wherein the oil-containing residue includes wax oil, heavy oil, additives, and a catalyst.

Further, according to the embodiment of the application, wherein the extraction solvent is one or more of C3-C5 alkane.

Further, according to the embodiment of the present application, wherein the extraction solvent is a mixed solvent of propane and n-butane, n-butane and isobutane, or a mixed solvent of n-butane and isopentane.

Further, according to the embodiment of the present application, wherein in the extraction step, the extraction effect is controlled by controlling the temperature condition at the time of operation.

Further, according to the embodiment of the present application, in the extraction step, the product asphalt/solid-solvent mixture is separated and recovered, the asphalt/solid is separated from the extraction solvent by a flash evaporation and steam stripping method to obtain an asphalt product, and the extraction solvent is recovered to the extraction step.

Further, according to the embodiment of the present application, in the separation step, the deasphalted oil in the separation product is separated from the extraction solvent by a flash evaporation and steam stripping method, so as to obtain a deasphalted oil product and recover the extraction solvent to the extraction step.

Further, according to the embodiment of the present application, wherein, in the separation step, the extraction solvent separated and recovered is recycled for use in the extraction step.

Further, according to the embodiment of the present application, wherein the separated and recovered extraction solvent is heat exchanged with the deasphalted oil and solvent mixture generated in the extraction step while being transferred.

Compared with the prior art, the method has the following beneficial effects: this application carries out extraction under the subcritical state through setting up a pair of oily residue of knockout tower, and the rethread sets up the mixed solution of knockout tower two pairs of deasphalted oil and extraction solvent and carries out the separation under the supercritical state, has improved the drawback that current traditional solvent deasphalting technique energy consumption is high, simplifies the flow operation, reduces by a wide margin and contains solid residue handling capacity, but the deasphalted oil cyclic utilization of extraction, the income is improved. And moreover, the softening point of the residue is improved, and the problem of difficult curing is thoroughly solved.

Drawings

The present application is further described below with reference to the drawings and examples.

FIG. 1 is a schematic block diagram of an oil-containing residue treatment system

Fig. 2 is a schematic diagram showing a specific structure of an oil-containing residue treatment system.

In the attached drawings

1. Feeding buffer tank 2, feeding pump 3 and separation tower I

4. Solvent pump 5, heat exchanger 6, heater one

7. A second separation tower 8, a second heater 9 and a first flash tank

10. A third heater 11, a first stripping tower 12 and a fourth heater

13. A second flash tank 14, a fifth heater 15 and a first stripping tower

16. Compressor 17, cooler I18 and cooler II

19. Recovery tank 20, third cooler 21 and delivery pump

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clear and fully described, embodiments of the present invention are further described in detail below with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of some embodiments of the invention and are not limiting of the invention, and that all other embodiments obtained by those of ordinary skill in the art without the exercise of inventive faculty are within the scope of the invention.

In the description of the present invention, it should be noted that the terms "center", "middle", "upper", "lower", "left", "right", "inner", "outer", "top", "bottom", "side", "vertical", "horizontal", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "a," "an," "first," "second," "third," "fourth," "fifth," and "sixth" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

For the purposes of simplicity and explanation, the principles of the embodiments are described by referring mainly to examples. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments. It will be apparent, however, to one skilled in the art that the embodiments may be practiced without these specific details. In some instances, well-known methods and structures have not been described in detail so as not to unnecessarily obscure the embodiments. In addition, all embodiments may be used in combination with each other.

The present application illustrates the specific structure of the oily residue treatment system in one embodiment by means of fig. 1-2. As shown in fig. 1-2, the oily residue treatment system comprises an extraction module, an asphalt extraction module, a deoiled asphalt extraction module and a solvent recovery module. Wherein, the oil-containing residue enters the extraction module and then is mixed with a solvent to separate asphalt and deasphalted oil. The extraction module is respectively connected with the asphalt extraction module and the deasphalted oil extraction module, the mixture of the asphalt and the solvent which are extracted and separated is conveyed to the asphalt extraction module, the asphalt is extracted from the solvent, the mixture of the deasphalted oil and the solvent which are extracted and separated is conveyed to the deasphalted oil extraction module, and the deasphalted oil is extracted from the solvent. The asphalt extraction module and the deasphalted oil extraction module are respectively connected with the solvent recovery module, the solvent recovery module is connected with the extraction module, and the solvent recovery module is used for recovering the solvent in the system and conveying the solvent to the extraction module for extraction.

In contrast, the oil-containing residue is a solid-oil mixture, which is generated during oil extraction and processing, and may be suspension bed residue, catalytic slurry oil, oil-containing sludge, etc., and contains a small amount of wax oil, unconverted heavy oil, and solids such as additives and catalysts. The oily residue is fed into a feed buffer tank 1 under level control. The pressure of the feeding buffer tank 1 can be kept at 4-5barg by fuel gas (or nitrogen gas), and the temperature is kept above 180 ℃, so that the low-temperature viscosity of the oily residue is prevented from increasing and a pipeline is prevented from being blocked. The extraction module is connected to feeding buffer tank 1, is provided with charge pump 2 between feeding buffer tank and extraction module, and charge pump 2 chooses for use to be applicable to the plunger pump or the diaphragm pump that contain solid material, inhales oiliness residue from feeding buffer tank 1, delivers to the pitch extraction tower after the pressurization.

In addition, the extraction module comprises a first separation tower 3, and the middle part of the first separation tower 3 is communicated with the feeding pump 2. The first separation tower 3 is also connected with a solvent pump 4, and the solvent pump 4 sends the solvent into the first separation tower 3 to mix the oily residue with the solvent. The oil-containing residue and the solvent may be mixed before entering the column or may be mixed in the first separation column 3, without limiting the present application.

And because the solid content is high, the first separation tower 3 is provided with a distributor with a large aperture and a filler with a large gap to prevent solid blockage, and the treatment capacity of the first separation tower 3 is controlled by a flow control valve on an outlet pipeline of the feed pump 2. The extraction solvent and the oily residue are fully contacted in a first separation tower 3. The volume ratio of solvent to feed oil-containing residue is 7-9:1 (by standard volume).

Specifically, the first separation column 3 is operated in a full liquid operation under the subcritical condition of the extraction solvent, and subcritical liquid-liquid extraction is carried out, so that the asphalt, heavy metals and solids in the oil-containing residue are insoluble in the solvent. The pitch and the solid are separated from the solvent and flow out of the bottom of the first separation tower 3 under the control of an interfacial meter. Wherein 1 standard volume of the exiting bitumen/solids will entrain less than about 1 standard volume (e.g., 0.8 standard volume) of extraction solvent. The asphalt/solid-solvent mixture (raffinate phase) discharged from the bottom of the first separation tower 3 subsequently enters an asphalt extraction module.

In separator one 3, the lighter deasphalted oil will dissolve in the extraction solvent. The solution of deasphalted oil and solvent (extract phase) is discharged from the top of the first separation column 3.

In the first separation column 3, the operation temperature, the solvent composition, the solvent ratio (solvent to oil-containing residue ratio) and the operation pressure all affect the product yield and quality. Since some process parameters (e.g., solvent composition, solvent ratio and operating pressure) are substantially fixed or set to relatively stable values, the operating temperature of the separation column one 3 is used as a main control variable for controlling the extraction effect in the same solvent. The yield of the deasphalted oil is effectively controlled by the operating temperature of the first separation tower 3: the high operation temperature can reduce the yield of the deasphalted oil, but has less impurities and high product quality; low operating temperatures will result in improved deasphalted oil yields but reduced product quality and increased impurities.

Based on this, the temperature at the top of the first separation column 3 is controlled by the third cooler 20 connected to the solvent pump 4, thereby controlling the yield of deasphalted oil. The low temperature is beneficial to liquid-liquid extraction, and the control of the extraction temperature by the first separation tower 3 can directly influence the product indexes of asphalt and deasphalted oil.

For oil-containing residues, the main purpose is to recover the deasphalted oil as much as possible, the deasphalted oil can be used as a feed to be recycled to a suspension bed hydrogenation device, and the suspension bed feed is very wide and is not influenced by carbon residue, heavy metals and the like. Therefore, the method has no strict requirement on the impurity content of the deasphalted oil. The yield of deasphalted oil can be flexibly adjusted according to the specific requirements of asphalt and deasphalted oil.

In addition, the solvent extraction module also comprises a second separation tower 7 connected with the top of the first separation tower 3, and the second separation tower 7 receives the extraction phase from the top of the first separation tower 3. A first heater 6 is disposed between the first separation column 3 and the second separation column 7 for heating the extraction phase to above the critical temperature of the extraction solvent through heat transfer oil (used as a heating medium) so as to recover the extraction solvent in a supercritical state in the deasphalted oil separation column. The purpose of raising the temperature of the solvent above the critical temperature is to take advantage of the low density nature of the solvent in the supercritical state. Above the critical temperature, when the solvent temperature rises, the density of the solvent is obviously reduced, and the value is close to the density of dense-phase gas, so that good separation effect can be obtained by utilizing the density difference. Without the need to completely vaporize the solvent, the solvent is recovered by phase transition.

At the final set temperature, the deasphalted oil is insoluble in the solvent, resulting in separation. In the second separation tower 7, about 90% of the solvent can be recovered by a phase-change-free separation method in a supercritical state, so that a large amount of steam is saved, and the heat energy required by the gasification phase change of the solvent is avoided.

The second separation tower 7 is operated in full liquid, and the separation product at the bottom of the tower (the standard volume ratio of the solvent carried by the deasphalted oil product to the deasphalted oil product is less than 1) is discharged from the bottom of the deasphalted oil separation tower under the control of an interface meter.

And the separated extraction solvent is discharged from the top of the second separation tower 7 and is conveyed to a third cooler 20, so that the extraction solvent is recycled in the solvent extraction module. And a heat exchanger 5 is arranged between the second separation tower 7 and the third cooler 20, and the heat exchanger 5 is also arranged between the first separation tower 3 and the first heater 6 and is used for exchanging heat and raising the temperature of the extraction phase at the top of the asphalt separation tower and the extraction solvent leaving the top of the deasphalted oil separation tower.

In addition, the bitumen extraction module comprises a flash drum one 9 and a stripping drum one 11. Wherein, the first flash tank 9 is connected with the bottom of the first separation tower 3, the bottom of the first flash tank 9 is connected with the first stripping tower 11, and the solid asphalt from the bottom of the first separation tower 3 is received. And a second heater 8 is arranged between the first separation tower 3 and the first flash tank 9, the solid asphalt from the bottom of the first separation tower 3 is decompressed through a liquid level control valve, heated and then sent to the first flash tank 9, and part of the solvent is recovered through the first flash tank 9 and then sent to the first stripping tower 11. And a third heater 10 is arranged between the first flash tank 9 and the first stripping tower 11 and is used for heating the solid asphalt flowing into the first stripping tower 11. And the heated solid asphalt enters a tower plate at the top of a first stripping tower 11 and contacts with stripping steam to strip residual solvent in the product, so that the content of the solvent carried in the product is reduced, and the solvent loss is reduced. Stripping steam is controlled by flow to enter the stripper column one 11 below the bottom tray. Flow control is to achieve more efficient stripping. The steam stripping adopts superheated steam, and can not be condensed in the tower.

The solid asphalt product is pumped out of the bottom of the first stripping tower 11 under the control of the liquid level and is pumped out by the asphalt product pump. The product mainly comprises asphalt and solids, has high softening point, is changed into solid after being cooled at normal temperature, can be directly transported after being crushed, and can be used as solid fuel or gasification furnace raw material for treatment. The product is rich in a large amount of heavy metals such as nickel, vanadium and the like, and the recovery of the heavy metals from ash after combustion is also a considerable benefit.

In addition, the deasphalted oil extraction module includes a second flash drum 13 and a second stripper 15. The second flash tank 13 is connected with the bottom of the second separation tower 7, and the bottom of the second flash tank 13 is connected with the second stripping tower 15 and receives the separated product from the bottom of the second separation tower 7. A fourth heater 12 is arranged between the second separation tower 7 and the second flash tank 13, the separated product at the bottom of the second separation tower 7 is decompressed and heated through a liquid level control valve and then is sent to the second flash tank 13, part of the solvent is recovered through flash evaporation, and then the separated product is sent to the second stripping tower 15. And a fifth heater 14 is arranged between the second flash tank 13 and the second stripping tower 15 and is used for heating the deasphalted oil flowing into the second stripping tower 15. And (3) after the temperature is raised, the deasphalted oil enters a tower plate at the top of a second stripping tower 15, and the deasphalted oil descends in the second stripping tower 15 to be contacted with stripping steam to strip out residual solvent in the product, so that the content of the solvent carried in the product is reduced, and the solvent loss is reduced. Stripping steam enters the bottom of the second stripping tower 15 below the tower plate through flow control. The steam stripping adopts superheated steam, and can not be condensed in the tower.

The deasphalted oil product is extracted from the bottom of the second 15 stripping tower, and the deasphalted oil product is fed into a tank field or a downstream device for treatment under the cascade control of the flow and the liquid level of the stripping tower, and is generally fed into a suspension bed hydrogenation device for treatment as a feed.

In addition, the solvent recovery module includes a recovery tank 19, the recovery tank 19 receives the solvent from the top of the first flash tank 9 and the second flash tank 13, and a second cooler 18 is provided on a pipe flowing into the recovery tank 19. The recovery tank 19 also receives the solvent from the tops of the first stripping tower 11 and the second stripping tower 15, a compressor 16 and a cooler 17 are arranged on a pipeline flowing into the recovery tank, and after the solvent and the water vapor are converged, the solvent is pressurized by the compressor 16 and is cooled by the recovered solvent cooler 17. Wherein the first cooler 17 and the second cooler 18 are generally provided as air coolers.

The cooled solvent and water enter the recovery tank 19 for solvent-water separation. The acidic water discharged from the recovery tank 19 contains H2S. The acidic water is pumped out from a collecting tank (not shown) at the bottom of the recovery tank 19 under liquid level control, and then sent to an outside-district acidic water treatment apparatus by an acidic water pump (not shown). The recovery tank 19 is provided with a discharge for non-condensable gases which may be discharged to a flare system or other processing equipment of the refinery.

The recovery tank 19 is connected to the solvent pump 4, and the recovered extraction solvent is sent back to the extraction module by the transfer pump 21. The solvent in the recovery tank 19 is mixed with the solvent output from the cooler three 20 at the inlet of the solvent pump 4, and after mixing, the pressure is increased by the solvent pump to be used as the extraction solvent of the asphalt separation tower.

In above-mentioned technical scheme, this application carries out extraction under the subcritical state to the oiliness residue through setting up knockout tower one 3, and the rethread sets up knockout tower two 7 and carries out the separation under the supercritical state to the mixed solution of deasphalting oil and extraction solvent, has improved the drawback that current traditional solvent deasphalting technique energy consumption is high, simplifies the flow operation, reduces the solid residue handling capacity by a wide margin, and the deasphalting oil cyclic utilization of extraction improves the income. And moreover, the softening point of the residue is improved, and the problem of difficult curing is thoroughly solved.

Based on the technical scheme, the embodiment of the application also discloses an oil-containing residue treatment method, which comprises the following steps:

and (3) extraction: mixing the oily residue to be treated with an extraction solvent in a subcritical state of the extraction solvent, wherein the volume ratio of the amount of the extraction solvent to the amount of the fed oily residue is 7-9:1 (according to a standard volume), separating asphalt and solids in the oily residue from the extraction solvent, and obtaining products of an asphalt/solid-solvent mixture and a deasphalted oil and solvent mixture;

In the above technical solution, the subcritical state of the extraction solvent means that the pressure exceeds the critical pressure of the extraction solvent, and the temperature does not exceed the critical temperature of the extraction solvent. By performing the subcritical liquid-liquid extraction in this transition state, the pitch, heavy metals and solids in the oil-containing residue are insoluble in the solvent, so that the pitch and solids can be separated from the extraction solvent.

The supercritical state of the extraction solvent refers to the critical pressure and critical temperature of the extraction solvent that are both exceeded, in order to take advantage of the low density properties of the extraction solvent in the supercritical state. Above the critical temperature, when the temperature of the extraction solvent rises, the density of the extraction solvent is obviously reduced, and the value is close to the density of dense-phase gas, so that the density difference can be utilized to obtain good separation effect, the solvent is not required to be completely gasified, and the solvent is recovered through phase change. At the final set temperature, the deasphalted oil is insoluble in the extraction solvent, resulting in separation. In the separation step, about 90% of the solvent can be recovered by the phase-change-free separation method in the supercritical state, so that a large amount of steam is saved to avoid the heat energy required by the gasification phase change of the solvent.

Wherein the extraction solvent is one or more of C3-C5 alkane; further preferably, a mixed solvent of propane and n-butane, n-butane and isobutane, or a mixed solvent of n-butane and isopentane.

Further, in the extraction step, the extraction effect can be controlled by controlling the temperature condition at the time of operation. Specifically, high operating temperatures will reduce the yield of deasphalted oil, but with fewer impurities and high product quality; low operating temperatures will result in improved deasphalted oil yields but reduced product quality and increased impurities. At the same time, the operating temperature is related to the characteristics of the extraction solvent: the light component extraction solvent requires a relatively low operation temperature, the heavy component extraction solvent requires a relatively high operation temperature, and the operation temperature range is determined by the critical temperature of the extraction solvent, which is not limited in this application.

In the extraction step, the product asphalt/solid-solvent mixture is separated and recovered, the asphalt/solid is separated from the extraction solvent by flash evaporation and steam stripping methods to obtain an asphalt product, and the extraction solvent is recovered to the extraction step.

In the separation step, the deasphalted oil and the extraction solvent in the separation product are separated by a flash evaporation and steam stripping method to obtain a deasphalted oil product, and the extraction solvent is recovered to the extraction step.

In the separation step, the extraction solvent separated and recovered is recycled for use in the extraction step. And when the separated and recovered extraction solvent is conveyed, the separated and recovered extraction solvent exchanges heat with the mixture of the deasphalted oil and the solvent generated in the extraction step, and part of heat energy is recovered.

The present application is further explained below by way of examples 1 to 12, but the present application is not limited to these examples.

[ examples 1 to 12 ]

The properties of the oily residues to be treated in examples 1 to 12 are shown in Table 1.

TABLE 1

The oily residue is put into the oily residue treatment system to be extracted according to the extraction method, different extraction solvents are adopted in the examples 1 to 12 respectively, and different process conditions (mainly operation temperature) are selected according to the characteristics of the extraction solvents. In this regard, the solvent ratio, the operation pressure, and the operation temperature of the pitch separation column all have an influence on the extraction effect, and the solvent ratio (volume ratio) 6: 1-9: 1, both belonging to the normal operating range, 8: 1 (volume ratio) is the most economical ratio. The higher the solvent ratio, the higher the yield, and the operating pressure is above the critical pressure of the used solvent, but the solvent ratio and the operating pressure have little influence on the extraction effect, the operating temperature of the asphalt separation tower has great influence on the extraction effect, and the asphalt separation tower is sensitive to the yield and the quality of the deasphalted oil and is easy to control and adjust. Therefore, generally speaking, the yield and quality of deasphalted oil is adjusted by varying the temperature of the bitumen separation column by selecting a fixed solvent ratio and operating pressure. The details are shown in Table 2.

TABLE 2

The distribution and physical properties of the extracted products obtained in the above examples are shown in Table 3, wherein the heavy oil contained no solids.

TABLE 3

As shown in tables 2 to 3, in the actual operation process, the operation temperature of the first separation column and the operation temperature of the second separation column can be determined according to the critical temperature of the extraction solvent, and meanwhile, in order to ensure the extraction effect and efficiency, the value range of the operation temperature generally exceeds 10 ℃. Within the operating temperature range, the high operating temperature will reduce the yield of deasphalted oil, but the impurities are few, and the product quality is high; low operating temperatures will result in improved deasphalted oil yields but reduced product quality and increased impurities.

Although the illustrative embodiments of the present application have been described above to enable those skilled in the art to understand the present application, the present application is not limited to the scope of the embodiments, and various modifications within the spirit and scope of the present application defined and determined by the appended claims will be apparent to those skilled in the art from this disclosure.

Claims

1. An oil-containing residue processing system, comprising:

a feed buffer tank for storing the oil-containing residue;

an extraction module connected with the feed buffer tank, the extraction module having:

the first separation tower is connected with the feeding buffer tank, and the oil-containing residues are fed into the first separation tower;

a solvent pump connected to the separation column to mix an extraction solvent with the oil-containing residue to obtain an extract phase and a raffinate phase;

the second separation tower is connected with the top of the first separation tower, the extract phase is sent to the second separation tower, and the top of the second separation tower is connected with the solvent pump through a pipeline;

wherein the operating pressure of the first separation column is higher than the critical pressure of the extraction solvent, and the operating temperature of the first separation column is lower than the critical temperature of the extraction solvent; the operating pressure of the second separation tower is higher than the critical pressure of the extraction solvent, and the operating temperature of the second separation tower is higher than the critical temperature of the extraction solvent.

2. An oil-containing residue processing system according to claim 1, wherein a feed pump is provided between the feed buffer tank and the first separation column.

3. The oil-containing residue treatment system according to claim 1, wherein the extraction module further comprises a first heater, and the first heater is arranged on a communication pipeline between the first separation tower and the second separation tower.

4. The oil-containing residue processing system of claim 1, wherein the extraction module further comprises a heat exchanger disposed at an intersection of the extract phase outlet line of the first separation column and the overhead outlet line of the second separation column.

5. The oil-containing residue treatment system of claim 1, wherein the extraction module further comprises a third cooler, and the third cooler is arranged on a communication pipeline between the second separation tower and the solvent pump.

6. The oily residue processing system of claim 1 wherein the oily residue processing system further comprises:

the asphalt extraction module is connected with the bottom of the first separation tower and is used for separating asphalt and an extraction solvent;

the deasphalted oil extraction module is connected with the bottom of the second separation tower through an extraction module and is used for separating deasphalted oil from an extraction solvent;

and the solvent recovery module is respectively communicated with the asphalt extraction module and the deasphalted oil extraction module through pipelines and is used for collecting the extraction solvent separated by the asphalt extraction module and the deasphalted oil extraction module.

7. The oily residue processing system of claim 6 wherein the bitumen extraction module comprises:

the first flash tank is connected with the bottom of the first separation tower through a pipeline;

the first stripping tower is connected with the bottom of the first flash tank through a pipeline.

8. The oil-containing residue processing system of claim 7, wherein the bitumen extraction module further comprises a second heater disposed in the communication conduit between the first separation column and the first flash tank.

9. The oil-containing residue processing system of claim 7, wherein the bitumen extraction module further comprises a third heater disposed in the communication conduit between the first flash tank and the first stripping column.

10. The oily residue processing system of claim 6 wherein the deasphalted oil extraction module comprises:

the second flash tank is connected with the bottom of the second separation tower through a pipeline;

and the second stripping tower is connected with the bottom of the second flash tank through a pipeline.

11. The oily residue processing system of claim 10 wherein the deasphalted oil extraction module further comprises a fourth heater disposed in the communication conduit between the second separation column and the second flash tank.

12. The oleaginous residue processing system of claim 10, wherein the deasphalted oil extraction module further comprises a heater five disposed in the communication conduit between the flash drum two and the stripper column two.

13. An oil-containing residuum processing system according to claim 6 wherein said solvent recovery module includes a recovery tank for centrally storing extraction solvent separated by said bitumen extraction module and said deasphalted oil module.

14. An oil-containing residue processing system as claimed in claim 13, wherein the recovery tank is in communication with the solvent pump.

15. The method for treating the oily residues is characterized by comprising the following steps:

16. The method as claimed in claim 15, wherein the oil-containing residue comprises wax oil, heavy oil, additives and catalyst.

17. The method of claim 15, wherein the extraction solvent is a mixture of one or more of C3 to C5 alkanes.

18. The method for treating oily residues according to claim 15, wherein the extraction solvent is a mixed solvent of propane and n-butane, n-butane and isobutane, or a mixed solvent of n-butane and isopentane.

19. The method as claimed in claim 15, wherein the extraction effect is controlled by controlling the temperature condition during the operation in the extraction step.

20. A process according to claim 15, wherein in the extraction step the product bitumen/solid-solvent mixture is separated and recovered, the bitumen/solid is separated from the extraction solvent by flashing and stripping to produce a bitumen product and the extraction solvent is recovered for use in the extraction step.

21. A process according to claim 15, wherein in the separation step the deasphalted oil is separated from the extraction solvent in the separation product by flash evaporation and stripping to obtain a deasphalted oil product and the extraction solvent is recovered for the extraction step.

22. The method according to claim 15, wherein the extraction solvent separated and recovered in the separation step is recycled to the extraction step.

23. The process of claim 22, wherein the extraction solvent is heat exchanged with the deasphalted oil and solvent mixture produced in the extraction step while the extraction solvent is being fed.