Separation and purification process and separation and purification process system for solid-containing oil product

Abstract

According to the solid-containing oil product separation and purification process and the separation and purification process system provided by the invention, the solid-containing oil product is treated by adopting the scheme of the invention, so that materials can be effectively separated, and the solid content in the separated clear liquid is reduced. The process comprises the following steps: (1) mixing and dissolving a solid-containing oil product and a composite solvent in a dissolving unit to obtain a dissolved material, the composite solvent comprising wash oil and light oil with a distillation range of 200-300 DEG C; (2) feeding the dissolved material into a centrifugal device of a separation unit, and centrifuging to obtain a centrifugal clear liquid and a centrifugal dry phase; the centrifugal clear liquid is fed into a filtering device of the separation unit to be filtered, and filtered clear liquid and concentrated liquid are obtained; and (3) carrying out flash evaporation treatment on the filtered clear liquid and the concentrated liquid in a flash evaporation unit respectively as flash evaporation feed liquid.

Description

Technical Field

[0001] The present invention relates to the technical field of coal chemical industry, and to a separation and purification process of solid oil products (such as oil residue, oil sludge, oil sand, etc.), and in particular to a separation and purification process of solid oil products and a separation and purification process system. Background Art

[0002] Solid-containing raw oil includes all solid-containing oils such as oil residue, oil sludge, oil sands, and oil mines, which can fully recover light oil and produce heavy oil to achieve solid-liquid separation. Specifically, solid-containing raw oil includes, for example, coal liquefaction oil residue, coal-oil co-refining oil residue, heavy oil suspension bed or slurry bed hydrogenation oil residue, oil field mining oil sludge, refinery oil sludge, ship warehouse bottom oil sludge, natural oil sands or oil mines, etc. The above raw materials are dissolved by solvents, and target products such as asphalt products can be obtained through separation, filtration, flash evaporation and other processes. Taking coal liquefaction oil residue as an example, the part that can be dissolved by the solvent is called the asphalt phase, and the part that cannot be dissolved by the solvent is called the solid phase. An organic solvent is used as an extractant to dissolve the organic matter contained in the coal direct liquefaction oil residue through processes such as dissolution, separation, filtration, and flash evaporation to produce high-quality product asphalt and by-product coal liquefaction solid fuel.

[0003] At present, the existing technology of direct coal liquefaction oil residue mostly adopts a single solvent to dissolve, and the solid content of the clear liquid separated after dissolution is 4-5%, the separation effect is poor, and it is impossible to produce high-purity products; and the solid content of the material after exposure flash evaporation is high, and it is difficult to pump and transport; and in the process of treatment, the heating furnace often has serious coking problems in the furnace tubes, which is very difficult to handle; in addition, the shell side of the high-solid content heat exchanger is also prone to serious blockage and high pressure difference.

[0004] In general, the main issues are as follows:

[0005] 1. The existing solvent dissolution process has poor separation effect after dissolution, high solid content of the clear liquid after separation, poor product stability and poor economic benefits.

[0006] 2. The solvent content and solid content in the clear liquid after separation are both high. After being heated in the heating furnace, the material is easily gasified and deposited in the furnace tube, causing coking of the heating furnace tube and unstable system pressure, which in turn causes system material cross-contamination and product unqualified problems.

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

[0008] 4. The solid content of the clear liquid after separation is high, and the solid content of the material after flash evaporation is high, which makes it difficult to transport by pump and has a high failure rate.

[0009] 5. The existing process cannot produce high-purity products and it is difficult to obtain a high asphalt yield, which has poor economic benefits and is not suitable for large-scale industrial production and occasions with high requirements for product quality. Summary of the invention

[0010] In view of at least one shortcoming existing in the prior art, the present invention provides a solid-containing oil separation and purification process and a separation and purification process system. By adopting the scheme of the present invention to treat solid-containing oil products, the materials can be effectively separated and the solid content in the clear liquid after separation can be reduced, which is beneficial to improving problems such as equipment blockage and pump transportation difficulties, improving the equipment operation cycle, and obtaining a variety of asphalt products.

[0011] To achieve the purpose, the present invention provides the following technical solutions:

[0012] The present invention provides a separation and purification process for solid-containing oil products, comprising the following steps:

[0013] (1) mixing and dissolving a solid oil product and a composite solvent in a dissolving unit to obtain a dissolved material, wherein the composite solvent comprises a wash oil and a light oil with a distillation range of 200-300° C.; preferably, the mass ratio of the solid oil product to the composite solvent is 1:2.8-4;

[0014] (2) sending the dissolved material into a centrifugal device of a separation unit for centrifugation to obtain a centrifuged clear liquid and a centrifuged dry phase; sending the centrifuged clear liquid into a filtering device of the separation unit for filtering to obtain a filtered clear liquid and a concentrated liquid;

[0015] (3) The filtered clear liquid and the concentrated liquid are respectively used as flash feed liquids for flash treatment in a flash unit to obtain an asphalt product; the flash unit comprises a first flash subunit and a second flash subunit, wherein the filtered clear liquid is treated in the first flash subunit to obtain a first asphalt product, and the concentrated liquid is treated in the second flash subunit 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 product and the composite solvent to obtain a dissolved material;

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

[0019] The flash evaporation unit comprises a first flash evaporation subunit and a second flash evaporation subunit. The first flash evaporation subunit is used to flash the filtered clear liquid to obtain a first asphalt product, and the second flash evaporation subunit is used to flash the concentrated liquid to obtain a second asphalt product.

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

[0021] The present invention adopts light oil and washing oil to form a composite solvent in proportion, which is used for dissolving and separating solid-containing oil products with high solid content. The separation efficiency is high, and there is a high density difference between materials during the extraction process. After that, through two-stage separation of centrifugation and filtration, a clear liquid with low solid content can be obtained, which is beneficial to improving the stability of product quality. In addition, different qualities of asphalt products can be obtained by filtering the clear liquid and the concentrated liquid, and higher quality asphalt products can be obtained at the same time. Moreover, in the subsequent flash unit treatment process, it is beneficial to reduce the risk of coking or clogging of the equipment, improve the stability of the device operation, and help extend the system operation cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of a dissolving unit and a separation unit of a separation and purification process system in one embodiment;

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

[0024] Figure 3 Schematic diagram of the first flash subunit in another embodiment. DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with examples. It should be understood that the following examples are only for a better understanding of the present invention and do not mean that the present invention is limited to the following examples.

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

[0027] The top, bottom, etc. mentioned or may be mentioned in this specification are defined relative to the structures shown in the drawings. They are relative concepts and may change accordingly according to their different positions and different usage conditions. The words "inside" and "outside" refer to the direction toward or away from the geometric center of a specific component, respectively. In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0028] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above in this application can be understood according to the specific circumstances.

[0029] In one aspect, the present invention provides a process for separating and purifying solid-containing oil products, comprising the following steps:

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

[0031] (2) sending the dissolved material into the centrifugal device 10 of the separation unit 200 for centrifugation to obtain a centrifuged clear liquid and a centrifuged dry phase; sending the centrifuged clear liquid into the filtering device 18 of the separation unit 200 for filtration to obtain a filtered clear liquid and a concentrated liquid;

[0032] (3) The filtered clear liquid and the concentrated liquid are respectively used as flash feed liquids for flash treatment in a flash unit to obtain an asphalt product; the flash unit includes a first flash subunit and a second flash subunit, wherein the filtered clear liquid is treated in the first flash subunit to obtain a first asphalt product (for example, high-grade asphalt), and the concentrated liquid is treated in the second flash subunit to obtain a second asphalt product (for example, medium-grade asphalt).

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

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

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

[0036] More specifically, the solid-containing oil product is, for example, one or more selected from coal direct liquefaction residue, coal-oil co-refining residue, heavy oil suspension bed or slurry bed hydrogenation residue, oil field exploitation sludge, refinery sludge, ship silo sludge, natural oil sands or oil mines; the method of the present invention is used to treat the above-mentioned solid-containing oil products, and the separation effect is good, and the asphaltene therein can be effectively separated to obtain a clear liquid with a low solid content, and an asphalt product with better quality can be obtained. In some embodiments, the solid-containing oil product is a high-solid-content oil, oil residue, etc., for example, a solid content of 5-80wt% and a viscosity of 20 to 30000cp; in some embodiments, the particle size of the solid particles in the solid-containing oil product is less than 210um.

[0037] The inventors of the present invention have found that the above-mentioned light oil and wash oil are compounded in the above-mentioned proportion to form a composite solvent, which is used for dissolving and separating solid-containing oil products with high solid content. The separation efficiency is high, and there is a high density difference between materials during the extraction process. After that, after two-stage separation by centrifugation and filtration, a clear liquid with a low solid content can be obtained. The solid content of the clear liquid can be reduced to ≤0.5%, which is beneficial to improving the stability of product quality. In addition, different qualities of asphalt products can be obtained by filtering the clear liquid and the concentrated liquid, and a higher quality asphalt product can be obtained at the same time. Moreover, in the subsequent flash unit treatment process, it is beneficial to reduce the risk of equipment coking or clogging, improve the stability of device operation, and help extend the system operation cycle.

[0038] In one embodiment, in step (1), the first flash evaporation subunit 300 and the second flash evaporation subunit have the same structure, respectively including an atmospheric tower 19 and a first heating device 20; the first flash evaporation subunit 300 is used as an example for description below, and the second flash evaporation subunit can refer to the description of the first flash evaporation subunit below, and no further description is given. Figure 2 In the first flash subunit 300, the feed liquid ( Figure 2The first gas phase and the flash feed liquid are preferably heat exchanged in the first heat exchanger 30, the first gas phase is converted into light oil, and part of the light oil is refluxed to the atmospheric tower 19; specifically, the light oil obtained by heat exchange in the first heat exchanger 30 enters the reflux tank 35, and then part of the light oil is circulated to the atmospheric tower 19 through the reflux pipeline 34 via the pump 32, and part of the light oil enters the solvent storage tank for recycling. 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; the flash feed liquid is sent to the first heating device 20 through pipeline 29 after heat exchange in the first heat exchanger 30 and the second heat exchanger 31, which can effectively reduce the load of the heating furnace and reduce the consumption of the device. The second flash subunit has the same structure as the first flash subunit, and its schematic diagram can also be seen in Figure 2 The description of the second flash subunit can refer to the description of the first flash subunit, except that the flash feed liquid of the second flash subunit is the concentrated liquid obtained in the filtering device 18, and the asphalt product finally obtained is, for example, intermediate asphalt. When a composite solvent with an initial boiling point of ≤220°C is used in step (1), it is particularly suitable to use a flash unit composed of an atmospheric tower and a first heating device in this embodiment for treatment in step (3). Preferably, the pressure of the atmospheric tower is controlled at 0.01-0.02MPaG, and the tower bottom temperature is preferably 310-330°C.

[0039] In another embodiment, in step (3), the first flash evaporation subunit and the second flash evaporation subunit have the same structure, respectively including an atmospheric tower 19, a first heating device 20, a second heating device 22 and a vacuum tower 24, and the first and second heating devices 20 and 22 can be integrated into a heating device 23. The first flash evaporation subunit 300 is taken as an example for introduction below, and the second flash evaporation subunit can refer to the description of the first flash evaporation subunit below, and no further description is given. The schematic diagram of the first flash evaporation subunit 300 in this embodiment is shown in FIG. Figure 3 , the flash feed liquid ( Figure 3The first heated material is sent to the atmospheric tower 19 through the first feed pipeline 25 for flash evaporation, and the first gas phase and the first bottom material are separated in the atmospheric tower 19. The first bottom material is sent to the second heating device 22 for heating to obtain the second heated material, and part of the second heated material is refluxed to the atmospheric tower 19 through the pipeline 42, for example, it is merged with the first heated material to the first feed pipeline 25 and then enters the atmospheric tower 19; part of the second heated material is sent to the vacuum tower 24 through the second feed pipeline 26 for flash evaporation to obtain the second gas phase and asphalt products (for example, high-grade asphalt). Preferably, the first gas phase and the flash feed liquid are heat exchanged in the first heat exchanger 30, the first gas phase is converted into light oil, and part of the light oil is refluxed to the atmospheric tower 19; specifically, the light oil obtained by heat exchange in the first heat exchanger 30 enters the reflux tank 35, and then part of the light oil is circulated to the atmospheric tower 19 through the reflux pipeline 34 via the pump 32, and part of the light oil enters the solvent storage tank for recycling. Preferably, the light oil obtained by condensing the second gas phase obtained in the vacuum tower 24 in the condenser 38 is partially refluxed to the vacuum tower 24 via the reflux pipeline 43; specifically, the light oil obtained by condensing the second gas phase in the condenser 38 enters the reflux tank 37, and part of the light oil is circulated to the vacuum tower 24 via the pump 39, and part of the light oil enters the solvent storage tank for recycling. Preferably, after part of the asphalt product is produced through pipeline 28 and the flash feed liquid after heat exchange in the first heat exchanger 30 is heat exchanged in the second heat exchanger 31; after the flash feed liquid is heat exchanged in the first heat exchanger 30 and the second heat exchanger 31, it is sent to the first heating device 20 through pipeline 29, which can effectively reduce the load of the heating furnace and reduce the consumption of the device. Preferably, after the asphalt product is produced by pump 41, part of the asphalt product is merged into the second feed pipeline 26 through pipeline 27 and then refluxed to the vacuum tower 24. Preferably, a vacuum tower feed heat exchanger 40 or a vacuum furnace 40 is provided on the second feed pipeline 26 connected to the feed port of the vacuum tower 24. Figure 3 In the vacuum tower 24 shown, the vacuum operating condition is provided by the vacuum pump 36. As for the second flash subunit, its structure is the same as the first flash subunit 300, and its schematic diagram can also be seen in Figure 3The description of the second flash subunit can refer to the description of the first flash subunit above, except that the flash feed liquid of the second flash subunit is the concentrated liquid obtained in the filtering device 18, and the final asphalt product is, for example, intermediate asphalt. In this example, the atmospheric tower, the first heating device, the second heating device and the vacuum tower are cleverly integrated and designed in terms of flow direction. The flash feed liquid is first heated in the first heating device, then enters the atmospheric tower for flash evaporation to remove the gas phase, and then enters the second heating device for heating. Part of the second heated material obtained by the second heating device is refluxed into the atmospheric tower, and part is sent to the vacuum tower. The heavy component material at the bottom of the atmospheric tower is circulated for heat extraction. Through the above preferred method, the problem of vaporization and coking of light components in the furnace tube of the heating device can be effectively solved, and the problem of deposition in the shell side of the heat exchanger can be avoided. At the same time, the system can be efficiently utilized and the heat load can be reduced. Using vacuum operation to treat solid-containing oil products with a high boiling point can effectively reduce the evaporation temperature and reduce the harshness of the equipment requirements; at the same time, the volatile components are easy to volatilize, shortening the time required for drying. When a composite solvent with an initial boiling point of >220°C (e.g., 220°C < initial boiling point ≤ 300°C) is used in step (1), a flash unit composed of an atmospheric pressure tower, a first heating device, a second heating device, and a vacuum tower in this embodiment is particularly suitable for treatment in step (3). Preferably, the pressure of the atmospheric pressure tower is controlled at 0.01-0.02MPaG, and the tower bottom temperature is preferably 310-330°C; preferably, the pressure of the vacuum tower is controlled at 0.01-0.04MPaA, and the tower bottom temperature is preferably 295-320°C.

[0040] Figure 2 , Figure 3 In the two illustrated first flash subunits (or second flash subunits), in the pipeline (e.g., the first feed pipeline 25) connected to the feed port of the atmospheric tower 19 for introducing the feed liquid into the atmospheric tower 19, the pipe section near the feed port of the atmospheric tower 19 is an expanded section (not shown in the figure), and the expansion multiple is preferably 5-15 times. In the pipeline (e.g., the second feed pipeline 26) connected to the feed port of the vacuum tower 24 for introducing the feed liquid into the vacuum tower 24, the pipe section near the feed port of the vacuum tower 24 is an expanded section (not shown in the figure), and the expansion multiple is preferably 5-15 times; preferably, the expanded section of each of the above pipe sections is provided with a wear-resistant lining. The feed pipeline design with an expanded section can effectively reduce the surge in flow rate caused by the rapid gasification of the oil product, and avoid pipeline wear caused by the high solid content in the oil product.

[0041] Specifically, see Figure 1The dissolving unit includes a dissolving tank 8 for contacting the solid oil product and the composite solvent for mixed dissolution. The solid oil product and the composite solvent flow through the steam generator 6 and the cooler 7 for heat exchange and then enter the dissolving tank 8, thereby realizing effective use of heat. The dissolving tank can be equipped with a stirring device, such as a frame type and a paddle type combined stirring method; the residence time of the material 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 Figure 1-3 , the system comprises a dissolution unit 100, a separation unit 200 and a flash unit;

[0043] The dissolving unit is used to mix and dissolve the solid-containing oil product and the composite solvent to obtain dissolved materials;

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

[0045] The flash unit includes a first flash subunit and a second flash subunit. The first flash subunit is used to flash the filtered clear liquid to obtain a first asphalt product (such as high-grade asphalt), and the second flash subunit is used to flash the concentrated liquid to obtain a second asphalt product (such as medium-grade asphalt).

[0046] In one example, when a composite solvent with an initial boiling point of ≤220°C is used, it is not necessary to perform vacuum flash evaporation. The flash evaporation unit is, for example, Figure 2 The first flash evaporation subunit and the second flash evaporation subunit have the same structure, and respectively include an atmospheric tower 19 and a first heating device 20; the first flash evaporation subunit 300 is taken as an example for description below, see Figure 2The first heating device 20 is used to heat the filtered clear liquid from the filtering device 18 as the flash feed liquid to obtain the first heated material; the atmospheric tower 19 is used to flash the first heated material and obtain the first gas phase and the asphalt product, and the atmospheric tower 19 is connected to a pump 41 and a pipeline 28 for extracting the asphalt product. Preferably, the flash unit also 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 is heat exchanged to obtain light oil; the flash 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 successively heat exchanged in 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 unit further comprises a reflux pipeline 34 for returning part of the light oil obtained by heat exchange of the first gas phase to the atmospheric tower 19, while part of the light oil is sent to the solvent storage tank for recycling; specifically, a reflux tank 35 and a pump 32 are provided on the reflux pipeline 34, and the light oil obtained by the first heat exchanger 30 first enters the reflux tank 35 and is then sent to the downstream through the pump 32. As for the second flash subunit, its structure is the same as that of the first flash subunit 300, and its schematic diagram can also be seen in Figure 2 The description of the second flash subunit can refer to the description of the first flash subunit 300, except that the flash feed liquid of the second flash subunit is the concentrated liquid obtained in the filtration device 18, and the final asphalt product is, for example, intermediate asphalt, which will not be described in detail. Preferably, the pressure of the atmospheric tower is controlled at 0.01-0.02 MPaG.

[0047] In another example, when a composite solvent having an initial boiling point higher than 220° C. is used, 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, wherein the first heating device 20 and the second heating device 22 can be integrated into a heating device 23; the first flash evaporation subunit 300 and the second flash evaporation subunit have the same structure, and the first flash evaporation subunit 300 is taken as an example for description below, see Figure 3, the first heating device 20 is used to heat the filtered clear liquid as the flash feed liquid to obtain the first heated material. The atmospheric tower 19 and the first heating device 20 are connected through the first feed pipeline 25, which is used to flash the first heated material and obtain the first gas phase and the first bottom material. The first bottom material is extracted by pump 33 and sent to the second heating device 22. The second heating device 22 is used to heat the first bottom material and obtain the second heated material. The second heating device 22 and the atmospheric tower 19 are connected through the second heated material reflux pipeline 42 so that part of the second heated logistics flows back to the atmospheric tower 19. The second heating device 22 and the vacuum tower 24 are connected through the second feed pipeline 26 to send part of the second heated material to the vacuum tower 24. The vacuum tower 24 is used to flash the second heated material and obtain the second gas phase and asphalt products. The asphalt products are extracted by pump 41. Preferably, the flash 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 unit further 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 the pipeline 28, so that the heat in the system is efficiently utilized. Preferably, the flash unit further includes a reflux pipeline 34 for returning part of the light oil obtained through heat exchange in the first gas phase to the atmospheric tower 19. Specifically, a reflux tank 35 and a pump 32 are provided on the reflux pipeline 34. The light oil first enters the reflux tank 35, is extracted through the pump 32, part of it is returned to the atmospheric tower 19, and part of it enters the solvent storage tank as a recycled solvent. Preferably, the flash unit also includes a condenser 38 for condensing the second gas phase obtained from the vacuum tower 24 into light oil, and the flash unit also includes a reflux pipeline 43 for part of the light oil to reflux to the vacuum tower 24; specifically, the reflux pipeline 43 is provided with a reflux tank 37 and a pump 39, the light oil first enters the reflux tank 37, and then is produced by the pump 39, part of it refluxes to the vacuum tower 24, and part of it enters the solvent storage tank as a recycled solvent. Preferably, the vacuum tower 24 is also provided with an asphalt product reflux pipeline 27, which is used to reflux part of the asphalt product to the vacuum tower 24 after being produced by the pump 41. Preferably, a vacuum tower 24 feed heat exchanger or a vacuum furnace 40 is provided on the second feed pipeline 26 connected to the feed port of the vacuum tower 24. For the second flash subunit, its structure is the same as that of the first flash subunit 300, and its schematic diagram can also be seen. Figure 3 The description of the second flash subunit can refer to the description of the first flash subunit 300, except that the flash feed liquid of the second flash subunit is the concentrated liquid obtained in the filtering device 18, and the final asphalt product is, for example, intermediate asphalt. Preferably, the pressure of the atmospheric tower is controlled at 0.01-0.02 MPaG; the pressure of the vacuum tower is controlled at 0.01-0.04 MPaA.

[0048] In a preferred embodiment, Figure 2 , Figure 3 For example, in the pipeline connected to the feed port of the atmospheric tower 19 for introducing feed liquid into the atmospheric tower 19 (for example, the first feed pipeline 25), the pipe section close to the feed port of the atmospheric tower 19 is an expanded section (not shown in the figure), and the expansion multiple is preferably 5-15 times; in the pipeline connected to the feed port of the vacuum tower 24 for introducing feed liquid into the vacuum tower 24 (for example, the second feed pipeline 26), the pipe section close to the feed port of the vacuum tower 24 is an expanded section (not shown in the figure), and the expansion multiple is preferably 5-15 times; preferably, a wear-resistant lining is provided in the pipeline of the expanded section.

[0049] Specifically, the dissolution unit 100 includes a dissolution tank 8 for contacting the solid oil product and the composite solvent for mixed dissolution. The feed inlet of the dissolution tank 8 is connected to a feed liquid input pipeline for conveying the solid oil product and the composite solvent. The feed liquid input pipeline is provided with a steam generator 6 and a cooler 7.

[0050] For example, Figure 1 As shown, the dissolving unit 100 further includes a solvent storage tank 3 for storing a composite solvent, and may further include a supplementary solvent tank 1 for storing a supplementary composite solvent. The composite solvent in the supplementary solvent tank 1 is supplemented 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 the solvent recovered in the system. The composite solvent and the solid-containing oil product in the solvent storage tank 3 are fed into the dissolving tank 8 via a pump 5 through a feed liquid input pipeline.

[0051] For example, Figure 1 As shown, the separation unit 200 further includes a centrifuge supernatant buffer tank 14 for storing the centrifuge supernatant obtained from the centrifuge device 10 and providing the centrifuge supernatant to the filtering device 18 via a pump 15 .

[0052] For example, Figure 1 As shown, the separation unit 200 also includes a first centrifugal dry phase screw conveyor 11, a centrifugal dry phase filtering device 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 filtering device 16 through the first centrifugal dry phase screw conveyor 11 for filtration, 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 is output to the subsequent device for processing through the bottom pump 13.

[0053] Specifically, the filter device 18 and the centrifugal dry phase filtration device 16 can be filter skids, and can be common filtration devices based on membrane filtration, metal filtration, filter cake layer filtration and other filtration forms; the filter device 18 preferably adopts continuous filtration, which can ensure the continuous and stable operation of the product and the stability of product quality, effectively reducing the operating cost; the machine pump used can be one or more of a plunger pump, a reciprocating pump or a high-solid centrifugal pump (a high-temperature solid-containing wear-resistant oil-coal slurry pump or a corrosion-resistant and wear-resistant pump, etc.); the steam generator, cooler, etc. used are preferably A wear-resistant and anti-blocking special heat exchanger is used to meet the heat exchange requirements of 0-80% solid content; the centrifugal device used can be a micro-positive pressure centrifuge, which can be a two-stage centrifugal separation, etc. The centrifuge is equipped with an effective mechanical seal, preferably to meet the feeding of extract liquid at a higher temperature (for example, a temperature of about 160°C) to prevent the volatilization of oil and gas at high temperature; the furnace tube of the heating device used can be a spiral spring tube or a racetrack-type large-radius furnace tube, and the medium flow rate in the furnace tube is preferably controlled at 0.5-5m / s, which is beneficial to further reduce the coking and wear of the heating furnace tube.

[0054] The invention is suitable for drying and separating large-scale petroleum wastes such as oil residue, oil sludge, oil sand, etc., and has strong operation continuity, is easy to achieve a high degree of automation, and completely recovers oil products (or solvents).

[0055] The present invention is further described in detail below through specific examples, but it should not be understood that the present invention is only limited to the following examples.

[0056] Where specific experimental steps or conditions are not specified in the examples, they can be carried out according to the operations or conditions of corresponding conventional experimental steps in the technical field.

[0057] Example 1

[0058] use Figure 1 , Figure 3 The process system shown is used to separate and purify the direct coal liquefaction residue of a coal chemical plant. Figure 1 , Figure 3 The description of the process system shown can be found in the previous description 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 210um, the asphalt material accounts for about 50wt%, the softening point is 198.8℃, the calorific value is 30.43MJ / kg, the n-hexane insoluble content is 80.61wt%, the tetrahydrofuran insoluble content is 48.10wt%, and the density is 1400kg / m 3 .

[0060] The composite solvent is prepared by mixing washing oil and light oil in a mass ratio of 4:6; the washing oil is obtained by fractionation of coal tar, and the distillation range is 230-300°C; the light oil is a fraction obtained by fractionation in an atmospheric tower of a coal direct liquefaction device, and the distillation range is 200-300°C, and the light oil mainly contains 8-11wt% of paraffins, 15-25wt% of cycloalkanes with a ring number of 1-3, and 58-66wt% of cycloaromatics with a ring number of 1-3. The initial distillation point of the composite solvent is greater than 220°C.

[0061] The coal direct liquefaction residue and the composite solvent in the solvent storage tank 3 are mixed in a mass ratio of 1:2.8-4, and then flow through the steam generator 6 and the cooler 7 for heat exchange and cooling (the temperature after cooling is higher than the flash point of the solvent by 30-50°C), and then enter the dissolving tank 8, where the mixing is carried out by a frame-type and paddle-type combined stirring method, and the mixture stays in the dissolving tank for 20-50 minutes. After stirring and extraction, the mixture is sent to the centrifugal device 10 for centrifugation by the pump 9. The centrifugal dry phase separated by the centrifugal device 10 is sent to the centrifugal dry phase filtering device 16 through the first centrifugal dry phase screw conveyor 11, and after filtration, it is sent to the centrifugal dry phase buffer tank 12 through the second centrifugal dry phase screw conveyor 17, and then sent to the subsequent device for treatment through the bottom pump 13. The recovered solvent can be returned to the solvent buffer tank for recycling.

[0062] The centrifugal clear liquid separated by the centrifugal device 10 flows into the centrifugal clear liquid buffer tank 14 by gravity, and is sent to the filtering device 18 through the pump 15. The filtered clear liquid is sent to the first flash evaporation subunit 300 for treatment, and the concentrated liquid is sent to the second flash evaporation subunit for treatment.

[0063] See also Figure 3In the first flash subunit 300, the filtered clear liquid flows through the first heat exchanger 30 and the second heat exchanger 31 for heat exchange preheating, enters the first heating device 20 of the heating equipment 23 through the pipeline 29 to exchange heat with the flue gas and is heated to about 300°C, then enters the expanded diameter section of the first feed pipeline 25 through the pressure holding regulating valve, and enters the atmospheric tower 19 after rapid pressure reduction and gasification in the expanded diameter section. The pressure of the atmospheric tower 19 is controlled at 0.01-0.02MPa(G), and the bottom temperature of the tower is between 310-330°C. Most of the solvent is separated from the top of the atmospheric tower 19 and produced 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 refluxed to the atmospheric tower 19 through 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 at the bottom of the atmospheric tower 19 is sent to the second heating device 22 of the heating device 23 through the pump 33 and heated to 350-370°C to obtain the second heated material. Part of the second heated material is output through the pipeline 42 and merged into the first feed pipeline 25 to mix with the first heated material and then enter the atmospheric tower; part of the second heated material enters the second feed pipeline 26, is heated in the vacuum tower feed heat exchanger or the vacuum furnace 40 (330-400°C), and then is reduced in pressure through the pressure holding regulating valve and enters In the expanded diameter section of the second feed pipeline 26, the material enters the vacuum tower 24 after rapid decompression and gasification in the expanded diameter section; the pressure of the vacuum tower 24 is controlled at 0.01-0.04MPa(A), the bottom temperature is between 295-320℃, and the remaining light components are further distilled out from the top of the vacuum tower 24 to obtain the second gas phase; the second gas phase is condensed into light oil through the condenser 38, and the light oil enters the reflux tank 37, after which part of the light oil is refluxed to the vacuum tower 24, and part of the light oil is sent to the solvent storage tank (or light oil tank). The asphalt product is obtained at the bottom of the vacuum tower.

[0064] The treatment process of the concentrated liquid in the second flash evaporation subunit is the same as the treatment process of the filtered clear liquid in the first flash evaporation subunit. Please refer to the previous description of the treatment of the filtered clear liquid in the first flash evaporation subunit, except that the filtered clear liquid is replaced by the concentrated liquid, and the rest will not be repeated.

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

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

[0067] Referring to Example 1, a coal direct liquefaction residue purification process using wash oil as solvent alone (i.e., a single solvent purification experiment) was also carried out. The results showed that the solid content of the clear liquid obtained by the single solvent purification process was between 3-6wt%, the quality of the asphalt products produced was unstable, and high-ash (ash content > 0.6% and ≤ 15%) asphalt accounted for 40%; while in Example 1 of the present invention, high-grade asphalt with an ash content of less than 0.1% was produced by filtering the clear liquid, and intermediate-grade asphalt with an ash content of 0.1-0.6% was produced by filtering the concentrated liquid, both of which were asphalt products with better quality than high-ash asphalt.

[0068] In addition, the furnace tubes of the heating device 23 of the single solvent purification process are prone to coking, and the furnace tube operation cycle is only about 3 months. However, the coking problem of the furnace tubes of the heating device 23 of Example 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 method is carried out in accordance with Example 1, except that the wash oil and the light oil are compounded in a mass ratio of 5:5.

[0071] Experimental results:

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

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

[0074] The operation period of the heating equipment 23 furnace tube is more than 12 months.

[0075] It is easy to understand that the above embodiments are only examples for clear explanation and do not mean that the present invention is limited thereto. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the protection scope of the present invention.

Claims

1. A process for separation and purification of solid-containing oil products, characterized in that: The steps include: (1) mixing and dissolving a solid oil product and a composite solvent in a dissolving unit to obtain a dissolved material, wherein the composite solvent comprises a wash oil and a light oil with a distillation range of 200-300° C.; preferably, the mass ratio of the solid oil product to the composite solvent is 1:2.8-4; (2) sending the dissolved material into a centrifugal device of a separation unit for centrifugation to obtain a centrifugal clear liquid and a centrifugal dry phase; Sending the centrifuged clear liquid into the filtering device of the separation unit for filtration to obtain filtered clear liquid and concentrated liquid; (3) The filtered clear liquid and the concentrated liquid are respectively used as flash feed liquids for flash treatment in a flash unit to obtain an asphalt product; the flash unit comprises a first flash subunit and a second flash subunit, wherein the filtered clear liquid is treated in the first flash subunit to obtain a first asphalt product, and the concentrated liquid is treated in the second flash subunit to obtain a second asphalt product.

2. The purification process according to claim 1, characterized in that: In step (1), in the composite solvent, the mass ratio of the wash oil to the light oil is 4:6-5:5; Preferably, the light oil is a fraction with a distillation range of 200-300° C. obtained by fractionation in an atmospheric pressure tower of a coal direct liquefaction device; Preferably, the light oil mainly comprises 8-11% by mass of paraffins, 15-25% by mass of cycloalkanes with a ring number of 1-3, and 58-66% by mass of cycloaromatics with a ring number of 1-3.

3. The purification process according to any one of claims 1 to 2, characterized in that: The solid oil product is selected from one or more of coal direct liquefaction residue, coal-oil co-refining residue, heavy oil suspension bed or slurry bed hydrogenation residue, oil field mining sludge, refinery sludge, ship silo sludge, natural oil sands or oil mines; and / or, the solid content of the solid-containing oil product is 5-80wt%; And / or, the particle size of the solid particles in the solid-containing oil product is less than 210 um.

4. The purification process according to any one of claims 1 to 3, characterized in that: The first flash subunit and the second flash subunit respectively include an atmospheric tower and a first heating device; the flash feed liquid is sent to the first heating device for heating, and the first heated material obtained is sent to the atmospheric tower through the first feed pipeline for flash evaporation, and the first gas phase and the asphalt product are separated in the atmospheric tower; preferably, the pressure of the atmospheric tower is controlled at 0.01-0.02MPaG, and the tower bottom temperature is preferably 310-330°C; Preferably, the light oil portion 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; Further preferably, 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 sent to the first heating device after heat exchange in the first heat exchanger and the second heat exchanger; Preferably, in step (1), the initial distillation point of the composite solvent is ≤220°C.

5. The purification process according to any one of claims 1 to 3, characterized in that: 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 sent to the first heating device for heating, and the obtained first heated material is sent to the atmospheric tower through the first feed pipeline for flash evaporation, and the first gas phase and the first bottom material are separated in the atmospheric tower; preferably, the pressure of the atmospheric tower is controlled at 0.01-0.02 MPaG, and the bottom temperature is preferably 310-330°C; The first tower bottom material is sent to the second heating device for heating, and the obtained second heated material is partially refluxed to the atmospheric tower, and the other part is sent to the vacuum tower through the second feed pipeline for flash evaporation to obtain a second gas phase and asphalt products; preferably, the pressure of the vacuum tower is controlled at 0.01-0.04 MPaA, and the tower bottom temperature is preferably 295-320°C; Preferably, the light oil portion obtained after the first gas phase and the flash feed liquid are heat exchanged in the first heat exchanger is refluxed to the atmospheric pressure tower; the light oil portion obtained after the second gas phase is condensed in the condenser is refluxed to the vacuum tower; Preferably, 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 sent to the first heating device after heat exchange in the first heat exchanger and the second heat exchanger; Preferably, the asphalt product is partially refluxed into the vacuum tower; Preferably, a vacuum tower feed heat exchanger or a vacuum furnace is provided on the second feed pipeline connected to the feed port of the vacuum tower; Preferably, in step (1), the initial distillation point of the composite solvent is greater than 220°C.

6. The purification process according to claim 4 or 5, characterized in that: In the pipeline connected to the feed port of the atmospheric tower for introducing the feed liquid into the atmospheric tower, the pipe section close to the feed port of the atmospheric tower is an expanded diameter section, preferably with an expansion multiple of 5-15 times; in the pipeline connected to the feed port of the vacuum tower for introducing the feed liquid into the vacuum tower, the pipe section close to the feed port of the vacuum tower is an expanded diameter section, preferably with an expansion multiple of 5-15 times; preferably, a wear-resistant lining is provided in the pipeline of the expanded diameter section; And / or, the dissolution unit comprises a dissolution tank for performing the mixed dissolution, and the solid-containing oil product and the composite solvent flow through a steam generator and a cooler for heat exchange before entering the dissolution tank.

7. A separation and purification process system for implementing the separation and purification process according to any one of claims 1 to 6, characterized in that: The system includes a dissolution unit, a separation unit and a flash unit; The dissolving unit is used to mix and dissolve the solid-containing oil product and the composite solvent to obtain a dissolved material; The separation unit comprises a centrifugal device and a filtering device; the centrifugal device is used to centrifuge the dissolved material to obtain a centrifugal clear liquid and a centrifugal dry phase, and the filtering device is used to filter the centrifugal clear liquid to obtain a filtered clear liquid and a concentrated liquid; The flash evaporation unit comprises a first flash evaporation subunit and a second flash evaporation subunit. The first flash evaporation subunit is used to flash the filtered clear liquid to obtain a first asphalt product, and the second flash evaporation subunit is used to flash the concentrated liquid to obtain a second asphalt product.

8. The separation and purification process system according to claim 7, characterized in that: The first flash evaporation subunit and the second flash evaporation subunit respectively 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 as the flash feed liquid to obtain a first heated material; The atmospheric pressure tower is used to flash the first heated material to obtain a first gas phase and an asphalt product; Preferably, the flash unit further comprises a first heat exchanger for exchanging heat between the flash feed liquid and the first gas phase, and obtaining light oil through heat exchange between the first gas phase; the flash unit further comprises a second heat exchanger for exchanging heat between the flash feed liquid after heat exchange in the first heat exchanger and the asphalt product; Preferably, the flash unit further comprises a reflux line for returning the light oil portion obtained by heat exchange of the first gas phase to the atmospheric pressure tower.

9. The separation and purification process system according to claim 7, 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 vacuum tower; The first heating device is used to heat the filtered clear liquid or the concentrated liquid as the flash feed liquid to obtain a first heated material; The atmospheric pressure tower and the first heating device are connected through a first feed pipeline, and are used to flash the first heated material to obtain a first gas phase and a first bottom material; The second heating device is used to heat the first tower bottom material to obtain a second heated material; The second heating device and the atmospheric tower are connected through a second heated material reflux pipeline so that part of the second heated material flow refluxes to the atmospheric tower; The second heating device is connected to the vacuum tower through a second feed pipeline to feed part of the second heated material into the vacuum tower; The vacuum tower is used to flash the second heated material to obtain a second gas phase and an asphalt product; Preferably, the flash unit further comprises a first heat exchanger for exchanging heat between the flash feed liquid and the first gas phase, and obtaining light oil through heat exchange between the first gas phase; the flash unit further comprises a second heat exchanger for exchanging heat between the flash feed liquid after heat exchange in the first heat exchanger and the asphalt product; Preferably, the flash unit further comprises a reflux pipeline for returning the light oil portion obtained by heat exchange of the first gas phase to the atmospheric pressure tower; Preferably, the flash unit further comprises a condenser for condensing the second gas phase into light oil, and the flash unit further comprises a reflux pipeline for partially returning the light oil obtained by condensing the second gas phase to the vacuum tower; Preferably, the vacuum tower is further provided with an asphalt product reflux pipeline for returning part of the asphalt product to the vacuum tower; Preferably, a vacuum tower feed heat exchanger or a vacuum furnace is provided on the second feed pipeline connected to the feed port of the vacuum tower.

10. The separation and purification process system according to claim 8 or 9, characterized in that: In the pipeline connected to the feed port of the atmospheric tower for introducing the feed liquid into the atmospheric tower, the pipe section close to the feed port of the atmospheric tower is an expanded diameter section, preferably with an expansion multiple of 5-15 times; in the pipeline connected to the feed port of the vacuum tower for introducing the feed liquid into the vacuum tower, the pipe section close to the feed port of the vacuum tower is an expanded diameter section, preferably with an expansion multiple of 5-15 times; preferably, a wear-resistant lining is provided in the pipeline of the expanded diameter section; And / or, the dissolution unit comprises a dissolution tank for performing the mixed dissolution, the feed inlet of the dissolution tank is connected to a feed liquid input pipeline for conveying the solid-containing oil product and the composite solvent, and the feed liquid input pipeline is provided with a steam generator and a cooler.

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