A solid oil-containing product separation and purification process and separation and purification process system

Abstract

The application provides a solid-containing oil product separation and purification process and a separation and purification process system. The solid-containing oil product is treated by adopting the scheme of the application, so that the material can be effectively separated, and the solid content in the clear liquid after separation is reduced. The process comprises the following steps: (1) mixing and dissolving the solid-containing oil product and a composite solvent in a dissolving unit to obtain dissolved material, wherein the composite solvent comprises washing oil and light oil with a distillation range of 200-300 DEG C; (2) sending the dissolved material into a centrifugal device of a separation unit to perform centrifugation to obtain centrifugal clear liquid and centrifugal dry phase; sending the centrifugal clear liquid into a filtering device of the separation unit to perform filtration to obtain filtered clear liquid and concentrated liquid; (3) respectively taking the filtered clear liquid and the concentrated liquid as flash evaporation feed liquid to perform flash evaporation treatment in a flash evaporation unit.

Description

Technical Field

[0001] This invention relates to the field of coal chemical technology, and to a separation and purification process for solid-containing oil products (such as oil residue, oil sludge, oil sand, etc.), specifically to a separation and purification process and system for solid-containing oil products. Background Technology

[0002] Solid feedstocks include all solid-containing oils such as oil residue, oil sludge, oil sands, and oilfield oil, which can fully recover light oils and produce heavy oils, achieving solid-liquid separation. Specifically, solid feedstocks include, for example, coal liquefaction oil residue, coal-oil co-refining oil residue, heavy oil suspension or slurry-bed hydrogenated oil residue, oilfield extraction sludge, refinery sludge, ship bilge sludge, natural oil sands, or oilfield oil. These feedstocks are dissolved in solvents, and after separation, filtration, flash evaporation, and other processes, the target product, such as asphalt, can be obtained. Taking coal liquefaction oil residue as an example, the portion that can be dissolved by solvents is called the asphalt phase, and the portion that cannot be dissolved by solvents is called the solid phase. Using organic solvents as extractants, the organic matter contained in the direct coal liquefaction oil residue is dissolved, separated, filtered, and flashed to produce high-quality asphalt and the byproduct coal liquefaction solid fuel.

[0003] Currently, most existing coal direct liquefaction oil residue technologies use a single solvent for dissolution. The resulting clear liquid has a solid content of 4-5%, resulting in poor separation and an inability to produce high-purity products. Furthermore, the material has a high solid content after exposure to flash evaporation, making pumping difficult. In addition, the heating furnace often suffers from severe coking in the furnace tubes during the processing, which is very difficult to handle. Moreover, the shell side of high-solids heat exchangers is also prone to severe blockage and high pressure differential.

[0004] Overall, the main problems are as follows:

[0005] 1. Existing solvent dissolution processes result in poor separation after dissolution, high solid content in the separated clear liquid, poor product stability, and poor economic benefits.

[0006] 2. The solvent and solid content in the separated clear liquid is relatively high. When heated in the furnace, the material is prone to gasification and deposition in the furnace tube, causing coking in the furnace tube and unstable system pressure. This leads to cross-contamination of materials in the system and product defects.

[0007] 3. The clear liquid after separation has a high solid content, and the return material from the pressure tower has a high solid content. The shell side of the heat exchanger is prone to deposition and blockage, which in turn affects the long-term stable operation of the unit.

[0008] 4. The clear liquid after separation has a high solid content, and the material after flash evaporation also has a high solid content, making pump transportation difficult and resulting in a high failure rate.

[0009] 5. Existing processes cannot produce high-purity products and are difficult to achieve high asphalt yields, resulting in poor economic benefits and making them unsuitable for large-scale industrial production and applications with high product quality requirements. Summary of the Invention

[0010] To address at least one deficiency in the existing technology, the present invention provides a process and system for separating and purifying solid-containing oils. By using the solution of the present invention to process solid-containing oils, the material can be effectively separated, the solid content in the clear liquid after separation can be reduced, which helps to improve problems such as equipment blockage and pump delivery difficulties, improve the equipment operating cycle, and obtain a variety of asphalt products.

[0011] To achieve its objective, the present invention provides the following technical solution:

[0012] This invention provides a process for separating and purifying solid-containing oils, comprising the following steps:

[0013] (1) The solid-containing oil and the composite solvent are mixed and dissolved in a dissolving unit to obtain a dissolved material, wherein the composite solvent includes wash oil and light oil with a distillation range of 200-300℃; preferably, the mass ratio of the solid-containing oil and the composite solvent is 1:2.8-4.

[0014] (2) The dissolved material is fed into the centrifuge device of the separation unit for centrifugation to obtain centrifuged clear liquid and centrifuged dry phase; the centrifuged clear liquid is fed into the filtration device of the separation unit for filtration to obtain filtered clear liquid and concentrated liquid;

[0015] (3) The filtered liquid and the concentrated liquid are used as flash feed liquids and flashed in a flash unit to obtain asphalt products; the flash unit includes a first flash sub-unit and a second flash sub-unit, wherein the filtered liquid is processed in the first flash sub-unit to obtain a first asphalt product, and the concentrated liquid is processed in the second flash sub-unit to obtain a second asphalt product.

[0016] The present invention also provides a separation and purification process system for implementing the separation and purification process described above, the system comprising a dissolution unit, a separation unit, and a flash evaporation unit;

[0017] The dissolving unit is used to mix and dissolve the solid-containing oil and the composite solvent to obtain a dissolved material.

[0018] The separation unit includes a centrifuge device and a filtration device; the centrifuge device is used to centrifuge the dissolved material to obtain a centrifuged clear liquid and a centrifuged dry phase, and the filtration device is used to filter the centrifuged clear liquid to obtain a filtered clear liquid and a concentrated liquid;

[0019] The flash evaporation unit includes a first flash evaporation subunit and a second flash evaporation subunit. The first flash evaporation subunit is used to flash evaporate the filtered liquid to obtain a first asphalt product, and the second flash evaporation subunit is used to flash evaporate the concentrate to obtain a second asphalt product.

[0020] The technical solution provided by this invention has the following beneficial effects:

[0021] This invention uses a composite solvent composed of light oil and wash oil in a specific ratio for the dissolution and separation of oil products with high solid content. It offers high separation efficiency and exhibits a significant density difference between materials during extraction. Subsequent centrifugation and filtration separate the product into a clear liquid with lower solid content, improving product quality stability. Furthermore, different qualities of asphalt products can be obtained from the filtered clear liquid and concentrated liquid, resulting in a higher-quality asphalt product. Moreover, in subsequent flash evaporation processes, it reduces the risk of coking or clogging in the equipment, improves operational stability, and extends the system's operating cycle. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the dissolution unit and separation unit of a separation and purification process system in one embodiment.

[0023] Figure 2 This is a schematic diagram of the first flash subunit in one embodiment;

[0024] Figure 3 This is a schematic diagram of the first flash subunit in another embodiment. Detailed Implementation

[0025] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" may be used herein to include any and all combinations of one or more of the associated listed items.

[0027] The directional terms such as "top" and "bottom" mentioned or potentially used in this specification are defined relative to the structures shown in the accompanying drawings. These are relative concepts and may therefore vary depending on their location and usage. The terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to direct connection, indirect connection through an intermediate medium, or internal connection between two components. Those skilled in the art can understand the specific meanings of the above terms within this application depending on the specific circumstances.

[0029] This invention provides a process for separating and purifying solid-containing oils, comprising the following steps:

[0030] (1) The solid oil and the composite solvent are mixed and dissolved in the dissolving unit 100 to obtain the dissolved material; wherein the composite solvent includes wash oil and light oil with a distillation range of 200-300℃; preferably, the mass ratio of the solid oil and the composite solvent is 1:2.8-4.

[0031] (2) The dissolved material is sent to the centrifuge device 10 of the separation unit 200 for centrifugation to obtain centrifuged clear liquid and centrifuged dry phase; the centrifuged clear liquid is sent to the filter device 18 of the separation unit 200 for filtration to obtain filtered clear liquid and concentrated liquid.

[0032] (3) The filtered liquid and the concentrated liquid are used as flash feed liquids and flashed in the flash unit to obtain asphalt products; the flash unit includes a first flash sub-unit and a second flash sub-unit, wherein the filtered liquid is treated in the first flash sub-unit to obtain a first asphalt product (e.g., high-grade asphalt), and the concentrated liquid is treated in the second flash sub-unit to obtain a second asphalt product (e.g., medium-grade asphalt).

[0033] Preferably, in step (1), the mass ratio of the washing oil and the light oil in the composite solvent is 4:6-5:5; using a composite solvent with the preferred mass ratio to dissolve the solid-containing oil is beneficial for subsequent separation to obtain a clear liquid with a lower solid content.

[0034] Preferably, the light oil mainly comprises 8-11% by mass of alkanes, 15-25% of cycloalkanes with 1-3 rings, and 58-66% of cycloaromatics with 1-3 rings.

[0035] Preferably, the light oil is a fraction obtained by fractionation in the atmospheric distillation tower of a direct coal liquefaction unit with a distillation range of 200-300℃.

[0036] More specifically, the solid-containing oil product is, for example, selected from one or more of the following: coal direct liquefaction residue, coal-oil co-refining residue, heavy oil suspension or slurry bed hydrogenated residue, oilfield extraction sludge, refinery sludge, ship bilge sludge, natural oil sands, or oilfield sludge. Using the method of the present invention to treat the above-mentioned solid-containing oil product results in good separation, effectively separating the asphaltenes to obtain a clear liquid with low solid content, and yielding a high-quality asphalt product. In some embodiments, the solid-containing oil product is a high-solids oil, oil residue, etc., for example, with a solid content of 5-80 wt% and a viscosity of 20-30000 cp; in some embodiments, the particle size of the solid particles in the solid-containing oil product is less than 210 μm.

[0037] The inventors have discovered that using the aforementioned light oil and wash oil in the above-mentioned proportions to form a composite solvent for the dissolution and separation of high-solid-content oil products results in high separation efficiency. During the extraction process, there is a significant density difference between materials. Subsequent centrifugation and filtration separate the solvent, yielding a clear liquid with a low solid content, which can be reduced to ≤0.5%. This improves the stability of product quality. Furthermore, different qualities of asphalt products can be obtained by filtering the clear liquid and the concentrate, resulting in higher-quality asphalt products. Moreover, in subsequent flash evaporation processes, this reduces the risk of equipment coking or clogging, improves the stability of the unit's operation, and extends the system's operating cycle.

[0038] In one embodiment, in step (1), the first flash subunit 300 and the second flash subunit have the same structure, each including an atmospheric pressure tower 19 and a first heating device 20. The first flash subunit 300 will be described below as an example; the second flash subunit can be described in the same way as the first flash subunit described below, without further elaboration. See also Figure 2 In the first flash evaporation subunit 300, the flash feed liquid ( Figure 2The filtered liquid obtained from the filtration device 18 is fed into the first heating device 20 for heating. The heated material is then fed into the atmospheric pressure tower 19 via the first feed line 25 for flash evaporation. In the atmospheric pressure tower 19, the first gas phase and the asphalt product (e.g., high-grade asphalt) are separated. Preferably, the first gas phase and the flash feed liquid are heat-exchanged in the first heat exchanger 30, where the first gas phase is converted into light oil. A portion of the light oil is then returned to the atmospheric pressure tower 19. Specifically, the light oil obtained from the heat exchanger 30 enters the reflux tank 35. Subsequently, a portion of the light oil is pumped by the pump 32 and circulated back into the atmospheric pressure tower 19 via the reflux line 34, while the remaining light oil enters the solvent storage tank for recycling. More preferably, the asphalt product output from pipeline 28 and the flash feed liquid after heat exchange in the first heat exchanger 30 are heat exchanged in the second heat exchanger 31. After heat exchange in the first heat exchanger 30 and the second heat exchanger 31, the flash feed liquid is sent to the first heating device 20 via pipeline 29. This can effectively reduce the load on the heating furnace and reduce device consumption. The second flash subunit has the same structure as the first flash subunit, and its schematic diagram can also be found in [reference needed]. Figure 2 The description of the second flash subunit can refer to the previous description of the first flash subunit. The difference is that the flash feed liquid of the second flash subunit is the concentrate obtained in the filtration device 18, and the final asphalt product is, for example, medium-grade asphalt. When a composite solvent with an initial boiling point ≤220℃ is used in step (1), the flash unit combining the atmospheric pressure tower and the first heating device in this embodiment is particularly suitable for processing in step (3). Preferably, the pressure of the atmospheric pressure tower is controlled at 0.01~0.02MPaG, and the bottom temperature of the tower is preferably 310-330℃.

[0039] In another embodiment, in step (3), the first flash subunit and the second flash subunit have the same structure, including an atmospheric pressure tower 19, a first heating device 20, a second heating device 22, and a pressure reducing tower 24, respectively. The first and second heating devices 20 and 22 can be integrated into a single heating device 23. The first flash subunit 300 will be used as an example for the following description; the second flash subunit can be described in the same way as the first flash subunit described below, without further elaboration. A schematic diagram of the first flash subunit 300 in this embodiment can be found here. Figure 3 Flash-evaporized feed liquid ( Figure 3Specifically, the filtered liquid obtained in the filtration device 18 is fed into the first heating device 20 for heating. The resulting first heated material is then fed into the atmospheric pressure tower 19 via the first feed line 25 for flash evaporation. In the atmospheric pressure tower 19, the first gas phase and the first bottom material are separated. The first bottom material is then fed into the second heating device 22 for heating to obtain the second heated material. A portion of the second heated material is refluxed back into the atmospheric pressure tower 19 via the pipeline 42, for example, by merging with the first heated material and then entering the atmospheric pressure tower 19 via the first feed line 25. A portion of the second heated material is fed into the vacuum tower 24 via the second feed line 26 for flash evaporation to obtain the second gas phase and asphalt product (e.g., high-grade asphalt). Preferably, the first gas phase and the flash feed liquid exchange heat in the first heat exchanger 30, whereby the first gas phase is converted into light oil, and a portion of the light oil is refluxed to the atmospheric distillation tower 19. Specifically, the light oil obtained from the heat exchange in the first heat exchanger 30 enters the reflux tank 35, and then a portion of the light oil is pumped by the pump 32 and circulated back to the atmospheric distillation tower 19 via the reflux line 34, while the remaining light oil enters the solvent storage tank for recycling. Preferably, the light oil obtained from the second gas phase obtained in the vacuum distillation tower 24 after condensation in the condenser 38 is partially refluxed back to the vacuum distillation tower 24 via the reflux line 43. Specifically, the light oil obtained from the condensation of the second gas phase in the condenser 38 enters the reflux tank 37, and a portion of the light oil is circulated back to the vacuum distillation tower 24 via the pump 39, while the remaining light oil enters the solvent storage tank for recycling. Preferably, a portion of the asphalt product, after being collected via pipeline 28, is heated in a second heat exchanger 31 after being heated by the first heat exchanger 30. After heat exchange in the first and second heat exchangers 31, the flash feed liquid is then sent to the first heating device 20 via pipeline 29. This effectively reduces the load on the heating furnace and lowers equipment consumption. Preferably, after being collected by pump 41, a portion of the asphalt product flows back to the pressure reducing tower 24 via pipeline 27 into the second feed pipeline 26. Preferably, the second feed pipeline 26, connected to the inlet of the pressure reducing tower 24, is equipped with a pressure reducing tower feed heat exchanger 40 or a pressure reducing furnace 40. Figure 3 In the pressure-reducing tower 24 shown, pressure-reducing operating conditions are provided by a vacuum pump 36. The second flash subunit has the same structure as the first flash subunit 300, and its schematic diagram can also be found in [reference needed]. Figure 3The description of the second flash subunit can refer to the previous description of the first flash subunit. The difference is that the flash feed liquid of the second flash subunit is the concentrate obtained in the filtration device 18, and the final asphalt product is, for example, medium-grade asphalt. In this example, the atmospheric distillation tower, the first heating device, the second heating device, and the vacuum distillation tower are cleverly integrated and designed with specific flow directions. The flash feed liquid is first heated in the first heating device, then flash-evaporated in the atmospheric distillation tower to remove the gas phase, and then heated in the second heating device. A portion of the second-heated material obtained in the second heating device is returned to the atmospheric distillation tower, and a portion is sent to the vacuum distillation tower. The heavy components at the bottom of the atmospheric distillation tower are recycled for heat extraction. Through the above-mentioned preferred method, the problem of light component vaporization and coking in the furnace tubes of the heating device can be effectively solved, avoiding the problem of heat exchanger shell-side deposition. At the same time, the system's internal volume is efficiently utilized, reducing the heat load. Using vacuum operation to process high-boiling-point solid-containing oils can effectively reduce the evaporation temperature and reduce the stringency of equipment requirements. At the same time, it makes the volatiles easier to volatilize, shortening the drying time. When a composite solvent with an initial boiling point > 220℃ (e.g., 220℃ < initial boiling point ≤ 300℃) is used in step (1), the flash evaporation unit combining the atmospheric pressure tower, the first heating device, the second heating device, and the vacuum tower in this embodiment is particularly suitable for processing in step (3). Preferably, the pressure of the atmospheric pressure tower is controlled at 0.01–0.02 MPaG, and the bottom temperature is preferably 310–330℃; preferably, the pressure of the vacuum tower is controlled at 0.01–0.04 MPaA, and the bottom temperature is preferably 295–320℃.

[0040] Figure 2 , Figure 3 In the two illustrated first flash sub-units (or second flash sub-units), the pipeline (e.g., first feed line 25) connected to the inlet of the atmospheric distillation tower 19 for introducing liquid feed into the atmospheric distillation tower 19 has an expanded diameter section (not shown in the figure) near the inlet, preferably with an expansion ratio of 5-15 times. Similarly, the pipeline (e.g., second feed line 26) connected to the inlet of the vacuum distillation tower 24 for introducing liquid feed into the vacuum distillation tower 24 has an expanded diameter section (not shown in the figure) near the inlet, preferably with an expansion ratio of 5-15 times. Preferably, the expanded diameter sections of the aforementioned pipelines are lined with wear-resistant linings. This design of feed lines with expanded diameter sections effectively reduces the velocity surge caused by rapid oil vaporization and avoids pipeline wear caused by high solid content in the oil.

[0041] Specifically, see Figure 1The dissolving unit includes a dissolving tank 8 for contacting and mixing solid oils and complex solvents. The solid oils and complex solvents flow through a steam generator 6 and a cooler 7 for heat exchange before entering the dissolving tank 8, thus achieving efficient utilization of heat. The dissolving tank may be equipped with a stirring device, such as a combination of frame and paddle stirring; the residence time of the materials in the dissolving tank is, for example, 20-50 minutes.

[0042] The present invention also provides a separation and purification process system for implementing the separation and purification process described above, see [link to documentation]. Figure 1-3 The system includes a dissolution unit 100, a separation unit 200, and a flash evaporation unit;

[0043] The dissolution unit is used to mix and dissolve solid oils and complex solvents to obtain dissolved materials;

[0044] The separation unit 100 includes a centrifuge device 10 and a filter device 18; the centrifuge device 10 is used to centrifuge the dissolved material to obtain a centrifuged clear liquid and a centrifuged dry phase, and the filter device 18 is used to filter the centrifuged clear liquid to obtain a filtered clear liquid and a concentrated liquid.

[0045] The flash evaporation unit includes a first flash evaporation subunit and a second flash evaporation subunit. The first flash evaporation subunit is used to flash evaporate the filtered liquid to obtain a first asphalt product (e.g., high-grade asphalt), and the second flash evaporation subunit is used to flash evaporate the concentrate to obtain a second asphalt product (e.g., medium-grade asphalt).

[0046] In one example, when using a composite solvent with an initial boiling point ≤220℃, reduced pressure flash evaporation may not be necessary. For example, see [link to flash evaporation unit]. Figure 2 The first flash subunit and the second flash subunit have the same structure, each including an atmospheric pressure tower 19 and a first heating device 20, respectively; the following description uses the first flash subunit 300 as an example. (See attached image.) Figure 2The first heating device 20 is used to heat the filtered liquid from the filtration device 18, which serves as the flash feed liquid, to obtain the first heated material. The atmospheric pressure tower 19 is used to flash evaporate the first heated material to obtain the first gas phase and asphalt product. The atmospheric pressure tower 19 is connected to a pump 41 and a pipeline 28 for extracting the asphalt product. Preferably, the flash evaporation unit further includes a first heat exchanger 30 for exchanging heat between the flash feed liquid and the first gas phase, so that the first gas phase obtains light oil through heat exchange. The flash evaporation unit also includes a second heat exchanger 31 for exchanging heat between the flash feed liquid after heat exchange in the first heat exchanger 30 and the asphalt product, so that the flash feed liquid is heat-exchanged successively by the first heat exchanger 30 and the second heat exchanger 31 before entering the first heating device 20 for heating, so that the heat is effectively utilized. Preferably, the flash evaporation unit further includes a reflux line 34 for returning a portion of the light oil obtained from the heat exchange of the first gas phase to the atmospheric distillation tower 19, while the remaining light oil is sent to a solvent storage tank for recycling. Specifically, the reflux line 34 is equipped with a reflux tank 35 and a pump 32. The light oil obtained from the first heat exchanger 30 first enters the reflux tank 35 and is then pumped downstream by the pump 32. The second flash evaporation subunit has the same structure as the first flash evaporation subunit 300, and its schematic diagram can also be found in [reference needed]. Figure 2 The description of the second flash subunit can refer to the previous description of the first flash subunit 300. The difference is that the flash feed liquid of the second flash subunit is the concentrate obtained in the filtration device 18, and the final asphalt product is, for example, medium-grade asphalt, which will not be elaborated further. Preferably, the pressure of the atmospheric pressure tower is controlled at 0.01 to 0.02 MPaG.

[0047] In another example, when using a composite solvent with an initial boiling point higher than 220°C, the first flash evaporation subunit 300 and the second flash evaporation subunit preferably include an atmospheric pressure tower 19, a first heating device 20, a second heating device 22, and a vacuum tower 24, respectively. The first heating device 20 and the second heating device 22 can be integrated into a single heating device 23. The first flash evaporation subunit 300 and the second flash evaporation subunit have the same structure. The following description uses the first flash evaporation subunit 300 as an example. (See [link to relevant documentation]). Figure 3The first heating device 20 is used to heat the filtered clear liquid, which serves as the flash feed liquid, to obtain a first heated material. The atmospheric distillation tower 19 and the first heating device 20 are connected via a first feed line 25, used to flash-evaporate the first heated material to obtain a first gas phase and a first bottoms material. The first bottoms material is collected by pump 33 and fed into a second heating device 22, which heats the first bottoms material to obtain a second heated material. The second heating device 22 and the atmospheric distillation tower 19 are connected via a second heated material reflux line 42 to allow a portion of the second heated material to reflux back to the atmospheric distillation tower 19. The second heating device 22 and the vacuum distillation tower 24 are connected via a second feed line 26 to feed a portion of the second heated material into the vacuum distillation tower 24, which flash-evaporates the second heated material to obtain a second gas phase and an asphalt product. The asphalt product is collected by pump 41. Preferably, the flash evaporation unit further includes a first heat exchanger 30 for exchanging heat between the flash feed liquid and the first gas phase, thereby obtaining light oil from the first gas phase through heat exchange; the flash evaporation unit also includes a second heat exchanger 31 for exchanging heat between the flash feed liquid after heat exchange in the first heat exchanger 30 and the asphalt product output through pipeline 28, so that the heat in the system is utilized efficiently. Preferably, the flash evaporation unit also includes a reflux pipeline 34 for returning a portion of the light oil obtained from the heat exchange in the first gas phase to the atmospheric distillation tower 19. Specifically, the reflux pipeline 34 is equipped with a reflux tank 35 and a pump 32. The light oil first enters the reflux tank 35, is pumped out by the pump 32, part of it is returned to the atmospheric distillation tower 19, and part of it is used as recycled solvent and enters the solvent storage tank. Preferably, the flash evaporation unit further includes a condenser 38 for condensing the second gas phase obtained from the vacuum distillation tower 24 into light oil. The flash evaporation unit also includes a reflux line 43 for returning a portion of the light oil to the vacuum distillation tower 24. Specifically, the reflux line 43 is equipped with a reflux tank 37 and a pump 39. The light oil first enters the reflux tank 37, then is collected by the pump 39, with a portion returning to the vacuum distillation tower 24 and the remainder entering a solvent storage tank as recycled solvent. Preferably, the vacuum distillation tower 24 is also equipped with an asphalt product reflux line 27 for returning a portion of the asphalt product collected by the pump 41 to the vacuum distillation tower 24. Preferably, a vacuum distillation tower 24 feed heat exchanger or vacuum furnace 40 is provided on the second feed line 26 connected to the feed inlet of the vacuum distillation tower 24. The second flash evaporation subunit has the same structure as the first flash evaporation subunit 300, and its schematic diagram can also be found in [reference needed]. Figure 3 The description of the second flash subunit can refer to the previous description of the first flash subunit 300. The difference is that the flash feed liquid of the second flash subunit is the concentrate obtained in the filtration device 18, and the final asphalt product is, for example, medium-grade asphalt. Preferably, the pressure of the atmospheric distillation tower is controlled at 0.01 to 0.02 MPaG; the pressure of the vacuum distillation tower is controlled at 0.01 to 0.04 MPaA.

[0048] In a preferred embodiment, with Figure 2 , Figure 3 For example, in the pipeline (e.g., the first feed pipeline 25) connected to the feed inlet of the atmospheric pressure tower 19 for introducing liquid into the atmospheric pressure tower 19, the section of the pipeline near the feed inlet of the atmospheric pressure tower 19 is an enlarged diameter section (not shown in the figure), preferably with an enlargement ratio of 5-15 times; in the pipeline (e.g., the second feed pipeline 26) connected to the feed inlet of the vacuum tower 24 for introducing liquid into the vacuum tower 24, the section of the pipeline near the feed inlet of the vacuum tower 24 is an enlarged diameter section (not shown in the figure), preferably with an enlargement ratio of 5-15 times; preferably, the pipe in the enlarged diameter section is provided with a wear-resistant lining.

[0049] Specifically, the dissolving unit 100 includes a dissolving tank 8 for contacting and mixing solid oil and compound solvent. The inlet of the dissolving tank 8 is connected to a liquid input pipeline for conveying solid oil and compound solvent. A steam generator 6 and a cooler 7 are provided on the liquid input pipeline.

[0050] For example, such as Figure 1 As shown, the dissolving unit 100 also includes a solvent storage tank 3 for storing the composite solvent, and may further include a replenishment solvent tank 1 for storing replenished composite solvent. The composite solvent in the replenishment solvent tank 1 is replenished to the solvent storage tank 3 via a pump 2 as needed. Preferably, the solvent storage tank 3 is also connected to a recovery solvent pipeline 44 for conveying recovered solvent within the system. The composite solvent and solid-containing oil products in the solvent storage tank 3 are pumped into the dissolving tank 8 via a feed inlet pipeline via a pump 5.

[0051] For example, such as Figure 1 As shown, the separation unit 200 also includes a centrifugal clear liquid buffer tank 14 for storing the centrifugal clear liquid obtained in the centrifugation device 10 and supplying the centrifugal clear liquid to the filtration device 18 via a pump 15.

[0052] For example, such as Figure 1 As shown, the separation unit 200 also includes a first centrifugal dry phase screw conveyor 11, a centrifugal dry phase filter 16, a second centrifugal dry phase screw conveyor 17, and a centrifugal dry phase buffer tank 12. The centrifugal dry phase obtained in the centrifugal device 10 is output to the centrifugal dry phase filter 16 for filtration through the first centrifugal dry phase screw conveyor 11, and then the filtered solid phase is output to the centrifugal dry phase buffer tank 12 through the second centrifugal dry phase screw conveyor 17, and then output to the subsequent device for processing via the bottom pump 13.

[0053] Specifically, the filtration device 18 and the centrifugal dry phase filtration equipment 16 can both be skid-mounted filters, and can be common filtration equipment based on membrane filtration, metal filtration, cake filter, etc.; the filtration device 18 preferably adopts continuous filtration, which can ensure continuous and stable operation of the product and the stability of product quality, effectively reducing operating costs; the pumps used can be one or more of the following: plunger pump, reciprocating pump, or high solids content centrifugal pump (high temperature solids content wear-resistant oil-coal slurry pump or corrosion-resistant and wear-resistant pump, etc.); the steam generator, cooler, etc. used are preferably... The heat exchanger is made of wear-resistant and anti-clogging special material, which can meet the heat exchange requirements of solid content from 0 to 80%. The centrifugal device used can be a micro-positive pressure centrifuge, which can be used for two-stage centrifugal separation, etc. The centrifuge is equipped with an effective mechanical seal, preferably capable of feeding extracts at higher temperatures (e.g., around 160°C) to prevent oil and gas from volatilizing at high temperatures. The furnace tubes of the heating device can be spiral spring tubes or racetrack-type large-radius furnace tubes. The medium flow velocity in the furnace tubes is preferably controlled at 0.5 to 5 m / s, which helps to further reduce coking and wear of the furnace tubes.

[0054] This invention is suitable for the drying and separation of petroleum waste such as oil residue, oil sludge, and oil sands on a large scale. It has strong operational continuity, is easy to achieve a high degree of automation, and the oil (or solvent) is thoroughly recovered.

[0055] The present invention will be further described in detail below through specific embodiments, but it should not be construed as the present invention being limited to the following embodiments.

[0056] Where specific experimental steps or conditions are not specified in the embodiments, the corresponding conventional experimental steps or conditions in this technical field can be followed.

[0057] Example 1

[0058] use Figure 1 , Figure 3 The process system shown separates and purifies the residue from direct coal liquefaction at a coal chemical plant. Regarding... Figure 1 , Figure 3 The process system shown is described above and will not be repeated here.

[0059] In this embodiment, the solid content of the coal direct liquefaction residue used is 40-48%, the particle size range of the solid particles is less than 210 μm, the bituminous substances account for about 50 wt%, the softening point is 198.8℃, the calorific value is 30.43 MJ / kg, the content of n-hexane insoluble matter is 80.61 wt%, the content of tetrahydrofuran insoluble matter is 48.10 wt%, and the density is 1400 kg / m³. 3 .

[0060] The composite solvent used is a mixture of wash oil and light oil in a mass ratio of 4:6. The wash oil is obtained from coal tar fractionation, with a distillation range of 230-300℃. The light oil is a fraction obtained from the atmospheric distillation tower of a direct coal liquefaction unit, with a distillation range of 200-300℃, mainly containing 8-11 wt% alkanes, 15-25 wt% cycloalkanes with 1-3 ring numbers, and 58-66 wt% cycloaromatics with 1-3 ring numbers. The initial boiling point of the composite solvent is >220℃.

[0061] The coal direct liquefaction residue and composite solvent in solvent storage tank 3 are mixed at a mass ratio of 1:2.8-4 and then flow through steam generator 6 and cooler 7 for heat exchange and cooling (the temperature after cooling is 30-50℃ higher than the solvent flash point). The mixture then enters dissolving tank 8, where it is mixed using a combination of frame and paddle stirring. After remaining in the dissolving tank for 20-50 minutes and undergoing stirring and extraction, it is pumped by pump 9 to centrifuge device 10 for centrifugation. The centrifuged dry phase obtained from centrifuge device 10 is sent to centrifuged dry phase filtration device 16 via first centrifuged dry phase screw conveyor 11. After filtration, it is sent to centrifuged dry phase buffer tank 12 via second centrifuged dry phase screw conveyor 17, and then sent to subsequent processing devices via bottom pump 13. The recovered solvent can be returned to the solvent buffer tank for recycling.

[0062] The centrifuged liquid obtained by centrifugation device 10 flows into centrifuged liquid buffer tank 14 by gravity, and is sent to filter device 18 by pump 15. The filtered liquid is sent to the first flash evaporation subunit 300 for processing, and the concentrated liquid is sent to the second flash evaporation subunit for processing.

[0063] See Figure 3In the first flash evaporation subunit 300, the filtered liquid flows through the first heat exchanger 30 and the second heat exchanger 31 for heat exchange and preheating. Then, it enters the first heating device 20 of the heating equipment 23 via pipeline 29 to exchange heat with the flue gas and is heated to about 300°C. After that, it enters the expansion section of the first feed pipeline 25 through the pressure regulating valve. After rapidly depressurizing and vaporizing in the expansion section, it enters the atmospheric pressure tower 19. The pressure of the atmospheric pressure tower 19 is controlled at 0.01~0.02MPa(G), and the bottom temperature is between 310-330°C. Most of the solvent is separated at the top of the atmospheric pressure tower 19 and is collected as the first gas phase. The first gas phase is condensed in the first heat exchanger 30 to obtain light oil, which enters the reflux tank 35. After that, part of the light oil is returned to the atmospheric pressure tower 19 via the reflux pipeline 34, and part of the light oil is sent to the solvent storage tank (or light oil tank). The first bottom material obtained from the bottom of the atmospheric distillation tower 19 is pumped by pump 33 into the second heating device 22 of the heating equipment 23 and heated to 350-370℃ to obtain the second heated material. Part of the second heated material is output through pipeline 42 and flows into the first feed pipeline 25 to mix with the first heated material before entering the atmospheric distillation tower. The other part of the second heated material enters the second feed pipeline 26, is heated (330-400℃) in the pressure reducing tower feed heat exchanger or pressure reducing furnace 40, and then the pressure is reduced by the pressure regulating valve before entering the atmospheric distillation tower. The expanded section of the second feed line 26 causes the material to rapidly depressurize and vaporize before entering the vacuum distillation tower 24. The pressure in the vacuum distillation tower 24 is controlled between 0.01 and 0.04 MPa (A), and the bottom temperature is between 295 and 320°C. The remaining light components are further distilled from the top of the vacuum distillation tower 24 to obtain a second gas phase. This second gas phase is condensed into light oil by the condenser 38. The light oil enters the reflux tank 37, and then part of the light oil is returned to the vacuum distillation tower 24, while the rest is sent to the solvent storage tank (or light oil tank). Asphalt product is obtained at the bottom of the vacuum distillation tower.

[0064] The treatment process of the concentrate in the second flash evaporation subunit is the same as that of the filtrate in the first flash evaporation subunit. Referring to the previous description of the treatment of the filtrate in the first flash evaporation subunit, the only difference is that the filtrate is replaced with the concentrate. The rest will not be repeated.

[0065] The asphalt product obtained from the filtered liquid in the first flash evaporation unit is high-grade asphalt (ash content less than 0.1%), and the asphalt product obtained from the concentrated liquid in the second flash evaporation unit is medium-grade asphalt (ash content between 0.1% and 0.6%).

[0066] The solid content of the filtered liquid obtained in the filtration device 18 is ≤0.5wt%.

[0067] Referring to Example 1, a coal direct liquefaction residue purification process using wash oil as a solvent (i.e., single-solvent purification experiment) was also carried out. The results showed that the solid content in the clear liquid obtained by the single-solvent purification process was between 3-6 wt%, and the quality of the produced asphalt products was unstable, with high ash content (ash content > 0.6% and ≤ 15%) asphalt accounting for 40%. In contrast, in Example 1 of this invention, the filtered clear liquid produced high-grade asphalt with an ash content of less than 0.1%, and the filtered concentrate produced medium-grade asphalt with an ash content between 0.1% and 0.6%, both of which are asphalt products of superior quality to high-ash asphalt.

[0068] In addition, the heating equipment 23 furnace tube in the single solvent purification process is prone to coking, and the furnace tube operation cycle is only about 3 months. However, the coking problem of the heating equipment 23 furnace tube in Embodiment 1 of the present invention is greatly improved, and the furnace tube operation cycle is increased to more than 6 months.

[0069] Example 2

[0070] The procedure was carried out in accordance with Example 1, except that the wash oil and light oil were mixed in a mass ratio of 5:5.

[0071] Experimental results:

[0072] The asphalt product obtained from the filtered liquid in the first flash evaporation unit is high-grade asphalt (ash content less than 0.1%), and the asphalt product obtained from the concentrated liquid in the second flash evaporation unit is medium-grade asphalt (ash content between 0.1% and 0.6%).

[0073] The solid content of the filtered liquid obtained in the filtration device 18 is ≤0.5wt%.

[0074] The operating cycle of the heating equipment 23 furnace tubes is more than 12 months.

[0075] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A process for separating and purifying solid-containing oils, characterized in that, Includes the following steps: (1) The solid oil and the composite solvent are mixed and dissolved in a dissolving unit to obtain the dissolved material. The composite solvent includes wash oil and light oil with a distillation range of 200-300℃. The mass ratio of the solid oil to the composite solvent is 1:2.8-4. (2) The dissolved material is fed into the centrifuge device of the separation unit for centrifugation to obtain a clear liquid and a dry phase. The centrifuged clear liquid is sent to the filtration device of the separation unit for filtration to obtain filtered clear liquid and concentrated liquid; (3) The filtered liquid and the concentrated liquid are used as flash feed liquids and flashed in a flash unit to obtain asphalt products; the flash unit includes a first flash sub-unit and a second flash sub-unit, wherein the filtered liquid is processed in the first flash sub-unit to obtain the first asphalt product, and the concentrated liquid is processed in the second flash sub-unit to obtain the second asphalt product; In step (1), when the initial boiling point of the composite solvent is ≤220℃, the first flash subunit and the second flash subunit respectively include an atmospheric pressure tower and a first heating device; the flash feed liquid is fed into the first heating device for heating, and the first heated material is fed into the atmospheric pressure tower through the first feed pipeline for flash evaporation, and the first gas phase and asphalt product are separated in the atmospheric pressure tower; In step (1), when the initial boiling point of the composite solvent is greater than 220°C, in step (3), the first flash evaporation subunit and the second flash evaporation subunit respectively include an atmospheric pressure tower, a first heating device, a second heating device, and a vacuum tower; the flash feed liquid is fed into the first heating device for heating, and the resulting first heated material is fed into the atmospheric pressure tower through the first feed pipeline for flash evaporation, and the first gas phase and the first bottom material are separated in the atmospheric pressure tower; the first bottom material is fed into the second heating device for heating, and the resulting second heated material is partially returned to the atmospheric pressure tower and partially fed into the vacuum tower through the second feed pipeline for flash evaporation, to obtain the second gas phase and the asphalt product.

2. The purification process according to claim 1, characterized in that, In step (1), the mass ratio of the washing oil and the light oil in the composite solvent is 4:6-5:

5.

3. The purification process according to claim 2, characterized in that, The light oil is a fraction obtained from the atmospheric distillation tower of a direct coal liquefaction unit, with a distillation range of 200-300℃.

4. The purification process according to claim 2, characterized in that, The light oil mainly comprises 8-11% by mass of alkanes, 15-25% of cycloalkanes with 1-3 rings, and 58-66% of cycloaromatics with 1-3 rings.

5. The purification process according to any one of claims 1-4, characterized in that, The solid oil product is selected from one or more of the following: coal direct liquefaction residue, coal-oil co-refining residue, heavy oil suspension bed or slurry bed hydrogenated residue, oilfield extraction sludge, refinery sludge, ship bilge sludge, natural oil sands or oil mines. And / or, the solid content of the solid-containing oil is 5-80 wt%; And / or, the particle size of the solid particles in the solid-containing oil is less than 210 μm.

6. The purification process according to any one of claims 1-4, characterized in that, The pressure of the atmospheric pressure tower is controlled at 0.01~0.02MPaG, and the bottom temperature of the tower is 310-330℃.

7. The purification process according to claim 6, characterized in that, The light oil obtained after heat exchange between the first gas phase and the flash feed liquid in the first heat exchanger is refluxed to the atmospheric pressure tower.

8. The purification process according to claim 7, characterized in that, The asphalt product and the flash feed liquid after heat exchange in the first heat exchanger are heat exchanged in the second heat exchanger; the flash feed liquid is then fed into the first heating device after heat exchange in the first and second heat exchangers.

9. The purification process according to any one of claims 1-4, characterized in that, The pressure of the pressure reducing tower is controlled at 0.01~0.04MPaA, and the temperature at the bottom of the tower is 295-320℃.

10. The purification process according to any one of claims 1-4, characterized in that, The light oil obtained after the first gas phase and the flash feed liquid exchange heat in the first heat exchanger is partially returned to the atmospheric pressure tower; the light oil obtained after the second gas phase is condensed in the condenser is partially returned to the vacuum tower.

11. The purification process according to any one of claims 1-4, characterized in that, The asphalt product and the flash feed liquid after heat exchange in the first heat exchanger are heat exchanged in the second heat exchanger; the flash feed liquid is then fed into the first heating device after heat exchange in the first and second heat exchangers.

12. The purification process according to any one of claims 1-4, characterized in that, When the initial boiling point of the composite solvent in step (1) is greater than 220°C, part of the asphalt product is refluxed into the vacuum tower.

13. The purification process according to any one of claims 1-4, characterized in that, A pressure reducing tower feed heat exchanger or pressure reducing furnace is provided on the second feed pipeline connected to the feed inlet of the pressure reducing tower.

14. The purification process according to any one of claims 1-4, characterized in that, In the pipeline connected to the inlet of the atmospheric pressure tower for feeding liquid into the atmospheric pressure tower, the section of the pipe near the inlet of the atmospheric pressure tower is an enlarged diameter section; in the pipeline connected to the inlet of the vacuum pressure tower for feeding liquid into the vacuum pressure tower, the section of the pipe near the inlet of the vacuum pressure tower is an enlarged diameter section. And / or, the dissolving unit includes a dissolving tank for performing the mixed dissolution, wherein the solid-containing oil and the composite solvent flow through a steam generator and a cooler for heat exchange before entering the dissolving tank.

15. The purification process according to claim 14, characterized in that, The expansion factor of the pipe section near the feed inlet of the atmospheric distillation tower is 5-15 times; The pipe section near the feed inlet of the pressure reducing tower has an expansion ratio of 5-15 times.

16. The purification process according to claim 14, characterized in that, The expanded diameter section of the pipe is lined with a wear-resistant lining.

17. A separation and purification process system for implementing the separation and purification process according to any one of claims 1-16, characterized in that, The system includes a dissolution unit, a separation unit, and a flash evaporation unit; The dissolving unit is used to mix and dissolve the solid-containing oil and the composite solvent to obtain a dissolved material. The separation unit includes a centrifuge device and a filtration device; the centrifuge device is used to centrifuge the dissolved material to obtain a centrifuged clear liquid and a centrifuged dry phase, and the filtration device is used to filter the centrifuged clear liquid to obtain a filtered clear liquid and a concentrated liquid; The flash evaporation unit includes a first flash evaporation subunit and a second flash evaporation subunit. The first flash evaporation subunit is used to flash evaporate the filtered liquid to obtain a first asphalt product, and the second flash evaporation subunit is used to flash evaporate the concentrate to obtain a second asphalt product.

18. The separation and purification process system according to claim 17, characterized in that, The first flash evaporation subunit and the second flash evaporation subunit each include an atmospheric pressure tower and a first heating device; The first heating device is used to heat the filtered clear liquid or the concentrated liquid, which is used as flash evaporation feed liquid, to obtain the first heated material; The atmospheric pressure tower is used to flash evaporate the first heated material to obtain the first gas phase and asphalt product.

19. The separation and purification process system according to claim 18, characterized in that, The flash evaporation unit further includes a first heat exchanger for exchanging heat between the flash evaporation feed liquid and the first gas phase, and for obtaining light oil from the first gas phase through heat exchange; the flash evaporation unit further includes a second heat exchanger for exchanging heat between the flash evaporation feed liquid after heat exchange by the first heat exchanger and the asphalt product.

20. The separation and purification process system according to claim 18, characterized in that, The flash evaporation unit also includes a reflux line for returning a portion of the light oil obtained from the heat exchange of the first gas phase to the atmospheric pressure tower.

21. The separation and purification process system according to claim 17, characterized in that, The first flash evaporation subunit and the second flash evaporation subunit respectively include an atmospheric pressure tower, a first heating device, a second heating device, and a pressure reducing tower; The first heating device is used to heat the filtered clear liquid or the concentrated liquid, which is used as flash evaporation feed liquid, to obtain the first heated material; The atmospheric pressure tower and the first heating device are connected by the first feed pipeline, which is used to flash evaporate the first heated material to obtain the first gas phase and the first bottom material of the tower. The second heating device is used to heat the material at the bottom of the first tower to obtain the second heated material; The second heating device and the atmospheric pressure tower are connected by a second heated material return pipeline so that a portion of the second heated material flows back to the atmospheric pressure tower; The second heating device and the pressure reducing tower are connected through a second feed pipeline to feed a portion of the second heated material into the pressure reducing tower; The pressure reducing tower is used to flash evaporate the second heated material to obtain a second gas phase and asphalt products.

22. The separation and purification process system according to claim 21, characterized in that, The flash evaporation unit further includes a first heat exchanger for exchanging heat between the flash evaporation feed liquid and the first gas phase, and for obtaining light oil from the first gas phase through heat exchange; the flash evaporation unit further includes a second heat exchanger for exchanging heat between the flash evaporation feed liquid after heat exchange by the first heat exchanger and the asphalt product.

23. The separation and purification process system according to claim 21, characterized in that, The flash evaporation unit also includes a reflux line for returning a portion of the light oil obtained from the heat exchange of the first gas phase to the atmospheric pressure tower.

24. The separation and purification process system according to claim 21, characterized in that, The flash evaporation unit further includes a condenser for condensing the second gas phase into light oil, and the flash evaporation unit also includes a reflux line for partially returning the light oil obtained from the condensation of the second gas phase to the pressure reducing tower.

25. The separation and purification process system according to claim 21, characterized in that, The pressure relief tower is also equipped with an asphalt product return pipeline for returning a portion of the asphalt product to the pressure relief tower.

26. The separation and purification process system according to claim 21, characterized in that, A pressure reducing tower feed heat exchanger or pressure reducing furnace is provided on the second feed pipeline connected to the feed inlet of the pressure reducing tower.

27. The separation and purification process system according to any one of claims 21-26, characterized in that, In the pipeline connected to the inlet of the atmospheric pressure tower for feeding liquid into the atmospheric pressure tower, the section of the pipeline near the inlet of the atmospheric pressure tower is an expansion section; in the pipeline connected to the inlet of the vacuum pressure tower for feeding liquid into the vacuum pressure tower, there is also an expansion section. And / or, the dissolving unit includes a dissolving tank for performing the mixed dissolution, the inlet of the dissolving tank being connected to a feed line for conveying the solid oil and the composite solvent, the feed line being equipped with a steam generator and a cooler.

28. The separation and purification process system according to claim 27, characterized in that, The expansion factor of the pipe section near the feed inlet of the atmospheric distillation tower is 5-15 times; The pipe section near the feed inlet of the pressure reducing tower has an expansion ratio of 5-15 times.

29. The separation and purification process system according to claim 27, characterized in that, The expanded diameter section of the pipe is lined with a wear-resistant lining.

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