Oil-containing sludge extraction device and extraction method for oil-containing sludge

Abstract

The present invention discloses an oil-containing sludge extraction device, which relates to the field of environmental protection technology. It includes a supply module for providing supercritical carbon dioxide, a drum extractor for performing extraction operations on oil-containing sludge, and a post-treatment module for separating extraction products and recovering separated products. The output end of the supply module is connected to the input end of the drum extractor, and the output end of the drum extractor is connected to the input end of the post-treatment module. A spiral protrusion and a stirring blade are arranged inside the drum extractor. The spiral protrusion is arranged on the inner wall of the drum extractor, and the stirring blade is arranged on a rotating shaft located inside the cavity of the drum extractor. The extraction process of supercritical carbon dioxide is carried out in the rolling drum extractor. The spiral protrusion and the stirring blade arranged inside the drum extractor can increase the contact efficiency between supercritical carbon dioxide and oil-containing sludge. The rolling of the drum extractor can also achieve a more active stirring effect, making the extraction efficiency of supercritical carbon dioxide higher and the extraction more complete.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection technologies, and particularly to an oil-containing sludge extraction device and an extraction method for oil-containing sludge, aiming to significantly improve the extraction efficiency, shorten the treatment time, and reduce energy consumption. Background Art

[0002] Oil-containing sludge refers to sludge mixed with heavy oils such as crude oil, various refined oils, and residual oils. As a typical industrial waste, it widely originates from multiple industries such as oil extraction, refining, and machining. Improper treatment of it not only occupies a large amount of land resources but also causes serious pollution to water bodies and soil, threatening ecological security. Currently, the main oil-containing sludge treatment technologies include chemical flocculation method, pyrolysis method, biological treatment method, and supercritical fluid extraction method, etc. The summary of each technology is as follows:

[0003] Chemical flocculation method: A technology that uses a flocculant to flocculate organic components and separate the product from sand, gravel, and soil. Although conventional chemical flocculation technology can initially separate oil sludge, it often requires adding a large amount of chemical agents, which not only increases the treatment cost but also poses a major problem in the subsequent treatment of agent residues, causing secondary pollution to the environment.

[0004] Pyrolysis method: Pyrolysis technology pyrolyzes organic substances in oil-containing sludge at high temperatures to produce various gaseous or liquid alkanes, cycloalkanes, aromatic hydrocarbons, alkenes, resins, and asphaltenes, etc. Although it can recover some energy, high-temperature operation consumes a huge amount of energy, and harmful gases may be generated during the process, requiring expensive tail gas treatment facilities.

[0005] Biological treatment method: Using microorganisms to degrade petroleum hydrocarbons in oil-containing sludge into harmless soil components. Although it is environmentally friendly, the treatment cycle is long, and it is greatly affected by factors such as microbial activity, temperature, and pH value, making it difficult to meet the requirements of large-scale and rapid treatment.

[0006] Supercritical fluid extraction method: Using supercritical carbon dioxide's special dissolution effect on certain special natural products to extract organic contaminants in oil-containing sludge. In recent years, supercritical CO2 extraction has attracted much attention due to its high efficiency and environmental friendliness. However, most existing supercritical extraction equipment uses static containers or simple stirring devices, resulting in the extraction efficiency being limited by the limited mass transfer surface area and unable to fully utilize the high-efficiency dissolution ability of supercritical CO2. In addition, high-efficiency supercritical extraction is often accompanied by high energy consumption requirements. How to reduce energy consumption while ensuring the treatment effect and meeting the requirements of quickly treating a large amount of oil-containing sludge to form an industrial-scale application is an urgent problem to be solved. Summary of the Invention

[0007] The purpose of the present invention is to provide an oily sludge extraction device to solve the problems existing in the above-mentioned prior art, so that the extraction process of supercritical carbon dioxide is carried out in a rolling drum extractor. The spiral protrusions and stirring blades inside the drum extractor can increase the contact efficiency between supercritical carbon dioxide and oily sludge. The overall rolling of the drum extractor can also play a more active stirring effect, so that the extraction efficiency of supercritical carbon dioxide is higher and the extraction is more thorough.

[0008] The present invention also provides a method for extracting oily sludge. Based on the above device, the extraction efficiency of oily sludge using supercritical carbon dioxide is higher and the extraction is more thorough.

[0009] To achieve the above object, the present invention provides the following solutions:

[0010] The present invention provides an oily sludge extraction device, comprising a supply module for providing supercritical carbon dioxide, a drum extractor for performing extraction operations on the oily sludge, and a post-processing module for separating the extraction product and recovering the separation product;

[0011] The output end of the supply module is connected to the input end of the drum extractor, and the output end of the drum extractor is connected to the input end of the post-processing module;

[0012] A spiral protrusion and a stirring blade are arranged in the drum extractor, wherein the spiral protrusion is arranged on the inner wall of the drum extractor, and the stirring blade is arranged on a rotating shaft located in the cavity of the drum extractor.

[0013] Preferably, the mathematical model of the spiral protrusion is z=α·r, wherein z is the spiral height, α is the inclination angle of the spiral, and r is the radial coordinate of the spiral protrusion in the drum extractor;

[0014] The surface profile of the stirring blade is a parabola.

[0015] Preferably, the supply module comprises a carbon dioxide supply module for providing carbon dioxide gas, a pretreatment module for generating supercritical carbon dioxide gas, and a delivery module for delivering supercritical carbon dioxide gas to the drum extractor;

[0016] The output end of the carbon dioxide supply module is connected to the input end of the pretreatment module, the output end of the pretreatment module is connected to the conveying module, and the output end of the conveying module is connected to the input end of the drum extractor.

[0017] Preferably, the carbon dioxide supply module is a carbon dioxide storage device.

[0018] Preferably, the pretreatment module includes a heating module for raising the temperature of the carbon dioxide gas and a pressurizing module for raising the pressure of the carbon dioxide gas;

[0019] The input end of the heating module is connected to the output end of the carbon dioxide supply module, the output end of the heating module is connected to the input end of the pressurizing module, and the input end of the pressurizing module is connected to the input end of the conveying module.

[0020] Preferably, the conveying module includes a heat-insulating and pressure-preserving conveying pipe and a flow controller for adjusting the conveying flow rate in the heat-insulating and pressure-preserving conveying pipe, and the flow controller is arranged on the heat-insulating and pressure-preserving conveying pipe;

[0021] The input end of the heat-insulating and pressure-preserving conveying pipe is connected to the output end of the pretreatment module, and the output end of the heat-insulating and pressure-preserving conveying pipe is connected to the input end of the drum extractor.

[0022] Preferably, the post-treatment module includes a centrifugal separation module for separating the extract from the solid residue, a low-temperature solidification and stratification module for obtaining the extract, and a purification and recovery module for recovering the carbon dioxide gas;

[0023] The input end of the centrifugal separation unit is connected to the output end of the drum extractor, the output end of the centrifugal separation unit is connected to the input end of the low-temperature solidification and stratification module, and the input end of the low-temperature solidification and stratification module is connected to the purification and recovery module.

[0024] The present invention also provides an extraction method for oily sludge, based on the above-mentioned oily sludge extraction device, including the following steps,

[0025] S1. Configure supercritical carbon dioxide: Heat and pressurize the carbon dioxide gas until supercritical carbon dioxide is obtained;

[0026] S2. Inject oily sludge: Inject the oily sludge into the drum extractor;

[0027] S3. Inject supercritical carbon dioxide and perform extraction: Inject the supercritical carbon dioxide obtained in S1 into the drum extractor, start the drum extractor, mix the oily sludge and the supercritical carbon dioxide in the drum extractor, and make the supercritical carbon dioxide extract the organic substances in the oily sludge;

[0028] S4. Separate the extract and recover carbon dioxide: Separate the mixture obtained in S3, first perform primary separation of the liquid-phase substance and the solid substance, and then perform secondary separation on the liquid-phase substance obtained by the preliminary separation to obtain the organic extract.

[0029] Preferably, in step S3, the supercritical carbon dioxide is continuously injected.

[0030] Preferably, in step S4, the primary separation method is centrifugal separation, and the secondary separation method is low-temperature solidification separation.

[0031] The present invention has achieved the following technical effects compared with the prior art:

[0032] The present invention provides an oil-containing sludge extraction device, enabling the extraction process of supercritical carbon dioxide to be carried out in a rolling drum extractor. The internal spiral protrusions and stirring blades in the drum extractor can increase the contact efficiency between supercritical carbon dioxide and oil-containing sludge, and the overall rolling of the drum extractor can also achieve a more active stirring effect, making the extraction efficiency of supercritical carbon dioxide higher and the extraction more thorough.

[0033] The present invention also provides an extraction method for oil-containing sludge. Based on the above device, the extraction efficiency of using supercritical carbon dioxide to extract oil-containing sludge is higher and the extraction is more thorough.

[0034] The present invention has also achieved the following technical effects compared with the prior art:

[0035] In the present invention, the drum extractor is provided with spiral protrusions and stirring blades with special shapes, which can specifically improve the contact effect inside the drum extractor. Compared with traditional stirring technologies, there are obvious improvements in aspects such as removal rate, treatment speed, energy consumption, and reduction of environmental impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the following described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 It is a schematic diagram of the overall composition structure of the device of the present invention;

[0038] Figure 2 It is a schematic diagram of the composition structure of the supply module in the present invention;

[0039] Figure 3 It is a schematic diagram of the internal structure of the drum extractor in the present invention;

[0040] Figure 4 It is a flow chart of the extraction method of the present invention.

[0041] Among them, 1. Supply module; 11. Carbon dioxide supply module; 12. Pretreatment module; 13. Conveying module; 2. Drum extractor; 21. Spiral protrusion; 22. Stirring blade; 3. Post-treatment module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] Next, in combination with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

[0043] The object of the present invention is to provide an oily sludge extraction device to solve the problems existing in the above-mentioned prior art, so that the extraction process of supercritical carbon dioxide is carried out in a rolling drum extractor. The internal spiral protrusions and stirring blades of the drum extractor can increase the contact efficiency between supercritical carbon dioxide and oily sludge, and the overall rolling of the drum extractor can also achieve a more active stirring effect, making the extraction efficiency of supercritical carbon dioxide higher and the extraction more thorough.

[0044] The present invention also provides an extraction method for oily sludge. Based on the above device, the efficiency of using supercritical carbon dioxide to extract oily sludge is higher and the extraction is more thorough.

[0045] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0046] As Figure 1 and 2 shown, the present invention provides an oily sludge extraction device, including a supply module 1 for providing supercritical carbon dioxide, a drum extractor 2 for extracting oily sludge, and a post-treatment module 3 for separating extraction products and recovering separated products. The output end of the supply module 1 is connected to the input end of the drum extractor 2, and the output end of the drum extractor 2 is connected to the input end of the post-treatment module 3. During extraction, sludge and supercritical carbon dioxide are successively introduced into the drum extractor 2 for extraction.

[0047] As Figure 3 shown, spiral protrusions 21 and stirring blades 22 are provided inside the drum extractor 2. The spiral protrusions 21 are provided on the inner part of the drum extractor 2, and the stirring blades 22 are provided on a rotating shaft 23 located inside the cavity of the drum extractor 2. In one embodiment, the mathematical model of the spiral protrusions 21 is z = α·r, where z is the spiral height, α is the inclination angle of the spiral, and r is the radial coordinate of the spiral protrusions in the drum extractor 2. The surface profile of the stirring blades 22 is a parabola, and its mathematical model is y = ax 2+bx + c, where a, b, and c are optimization parameters. The values of a, b, and c are determined according to the requirement of ensuring that the aspect ratio of the length to the width of the leaf surface contour of the stirring blade 22 is 1:0.618. The length of the leaf surface contour is the vertical distance from the vertex of the stirring blade 22 to the rotating shaft 23, and the width of the leaf surface contour is the contact length between the stirring blade 22 and the rotating shaft 23. The drum extractor 2 is a cylindrical drum, and the ratio of the bottom diameter to the height of the cylindrical drum is 1:2.

[0048] As Figure 1 shown, the supply module 1 includes a carbon dioxide supply module 11 for providing carbon dioxide gas, a pretreatment module 12 for generating supercritical carbon dioxide gas, and a delivery module 13 for delivering supercritical carbon dioxide gas to the drum extractor 2. The output end of the carbon dioxide supply module 11 is connected to the input end of the pretreatment module 12, the output end of the pretreatment module 12 is connected to the delivery module 13, and the output end of the delivery module 13 is connected to the input end of the drum extractor 2. In the supply module 1, carbon dioxide gas is converted into supercritical carbon dioxide that can be used for extraction. In one embodiment, the carbon dioxide supply module 11 is a carbon dioxide storage tank, and when supercritical carbon dioxide needs to be prepared, the carbon dioxide storage tank can output maintenance gas. The carbon dioxide supply module 11 can also be a carbon dioxide generator or a detachable carbon dioxide gas cylinder.

[0049] In one embodiment, the pretreatment module 12 includes a heating module for increasing the temperature of the carbon dioxide gas and a pressurizing module for increasing the pressure of the carbon dioxide gas. The input end of the heating module is connected to the output end of the carbon dioxide supply module 11, the output end of the heating module is connected to the input end of the pressurizing module, and the input end of the pressurizing module is connected to the input end of the delivery module 13. According to the generation conditions of supercritical carbon dioxide, the heating temperature is at least 31.1 °C, and the pressurizing pressure is at least 7.38 MPa. The pretreatment module 12 can also be a reaction device with both heating and pressurizing functions.

[0050] In one embodiment, the delivery module 13 includes a heat-insulating and pressure-maintaining delivery pipe and a flow controller for adjusting the delivery flow rate inside the heat-insulating and pressure-maintaining delivery pipe. The flow controller is arranged on the heat-insulating and pressure-maintaining delivery pipe. The input end of the heat-insulating and pressure-maintaining delivery pipe is connected to the output end of the pretreatment module 12, and the output end of the heat-insulating and pressure-maintaining delivery pipe is connected to the input end of the drum extractor 2. The flow controller can adjust the flow rate of supercritical carbon dioxide to be always in a reasonable state, and the heat-insulating and pressure-maintaining delivery pipe can keep the physical state of supercritical carbon dioxide unchanged, ensuring the extraction effect.

[0051] In one embodiment, the post-treatment module 3 includes a centrifugal separation module for separating the extract liquid from the solid residue, a low-temperature solidification and stratification module for obtaining the extract, and a purification and recovery module for recovering carbon dioxide gas. The input end of the centrifugal separation unit is connected to the output end of the drum extractor 2, the output end of the centrifugal separation unit is connected to the input end of the low-temperature solidification and stratification module, and the input end of the low-temperature solidification and stratification module is connected to the purification and recovery module. The centrifugal separation module can separate the liquid extract containing the extract and the solid particulate matter. The low-temperature solidification and stratification module performs liquid-phase separation by utilizing the different freezing points of different liquid substances.

[0052] A PLC control device is also provided in the present invention, which can automatically control and adjust the working states of the supply module 1, the drum extractor 2, and the post-treatment module 3. The PLC control device can implement functions such as error reporting and automatic shutdown.

[0053] The present invention also provides an extraction method for oily sludge, based on the above-mentioned oily sludge extraction device, as Figure 4 shown, including the following steps,

[0054] S1. Configure supercritical carbon dioxide: Heat and pressurize carbon dioxide gas until supercritical carbon dioxide is obtained.

[0055] S2. Inject oily sludge: Inject the oily sludge into the drum extractor 1.

[0056] S3. Inject supercritical carbon dioxide and perform extraction: Inject the supercritical carbon dioxide obtained in S1 into the drum extractor 1, start the drum extractor 1, and mix the oily sludge and supercritical carbon dioxide in the drum extractor 1 to make the supercritical carbon dioxide extract the organic substances in the oily sludge.

[0057] S4. Separate the extract and recover carbon dioxide: Separate the mixture obtained in S3. First, perform primary separation of the liquid-phase substance and the solid substance, and then perform secondary separation on the preliminarily separated liquid-phase substance to obtain the organic extract.

[0058] In step S3, supercritical carbon dioxide is continuously injected to maintain the temperature and pressure of the drum extractor 1. In step S4, the method of primary separation is centrifugal separation, and the method of secondary separation is low-temperature solidification separation.

[0059] In the present invention, specific examples are used to illustrate the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation on the present invention.

Claims

1. An oily sludge extraction device, characterized in that: It comprises a supply module (1) for providing supercritical carbon dioxide, a drum extractor (2) for performing an extraction operation on oily sludge, and a post-processing module (3) for separating the extraction product and recovering the separation product; The output end of the supply module (1) is connected to the input end of the drum extractor (2), and the output end of the drum extractor (2) is connected to the input end of the post-processing module (3); The drum extractor (2) is provided with a spiral protrusion (21) and a stirring blade (22); the spiral protrusion (21) is provided on the inner wall of the drum extractor (2); the stirring blade (22) is provided on a rotating shaft (23) located in the cavity of the drum extractor (2); the stirring blades (22) are arranged on the rotating shaft (23) at intervals along the axial direction of the rotating shaft (23); the surface profile of the stirring blade (22) is a parabola; and the mathematical model of the blade surface profile is y=ax 2 +bx+c, wherein a, b, and c are optimization parameters, and the values ​​of a, b, and c are determined to ensure that the aspect ratio of the blade surface profile of the stirring blade (22) is 1:0.618, the length of the blade surface profile is the vertical distance from the vertex of the stirring blade (22) to the rotating shaft (23), and the width of the blade surface profile is the contact length between the stirring blade (22) and the rotating shaft (23).

2. The oily sludge extraction device according to claim 1, characterized in that: The supply module (1) comprises a carbon dioxide supply module (11) for providing carbon dioxide gas, a pretreatment module (12) for generating supercritical carbon dioxide gas, and a delivery module (13) for delivering supercritical carbon dioxide gas to the drum extractor (2); The output end of the carbon dioxide supply module (11) is connected to the input end of the pretreatment module (12), the output end of the pretreatment module (12) is connected to the delivery module (13), and the output end of the delivery module (13) is connected to the input end of the drum extractor (2).

3. The oily sludge extraction device according to claim 2, characterized in that: The carbon dioxide supply module (11) is a carbon dioxide storage device.

4. The oily sludge extraction device according to claim 2, characterized in that: The pre-processing module (12) comprises a heating module for increasing the temperature of the carbon dioxide gas and a pressurizing module for increasing the pressure of the carbon dioxide gas; The input end of the heating module is connected to the output end of the carbon dioxide supply module (11), the output end of the heating module is connected to the input end of the pressurizing module, and the output end of the pressurizing module is connected to the input end of the conveying module (13).

5. The oily sludge extraction device according to claim 2, characterized in that: The conveying module (13) comprises a heat-insulating and pressure-maintaining conveying pipe and a flow controller for adjusting the conveying flow rate in the heat-insulating and pressure-maintaining conveying pipe, wherein the flow controller is arranged on the heat-insulating and pressure-maintaining conveying pipe; The input end of the heat-insulating and pressure-maintaining conveying pipe is connected to the output end of the pretreatment module (12), and the output end of the heat-insulating and pressure-maintaining conveying pipe is connected to the input end of the drum extractor (2).

6. The oily sludge extraction device according to claim 1, characterized in that: The post-processing module (3) comprises a centrifugal separation module for separating the extract from the solid residue, a low-temperature solidification stratification module for obtaining the extract, and a purification recovery module for recovering carbon dioxide gas; The input end of the centrifugal separation module is connected to the output end of the drum extractor (2), the output end of the centrifugal separation module is connected to the input end of the low-temperature solidification stratification module, and the output end of the low-temperature solidification stratification module is connected to the purification and recovery module.

7. A method for extracting oily sludge, characterized in that: The oily sludge extraction device according to any one of claims 1 to 6 comprises the following steps: S1. preparing supercritical carbon dioxide: heating and pressurizing carbon dioxide gas until supercritical carbon dioxide is obtained; S2, injecting oily sludge: injecting the oily sludge into the drum extractor (1); S3, injecting supercritical carbon dioxide and performing extraction: injecting the supercritical carbon dioxide obtained in S1 into the drum extractor (1), starting the drum extractor (1), mixing the oily sludge and the supercritical carbon dioxide in the drum extractor (1), and allowing the supercritical carbon dioxide to extract organic matter from the oily sludge; S4, separating the extract and recovering carbon dioxide: separating the mixture obtained in S3, firstly performing a primary separation of the liquid phase substance and the solid phase substance, and then performing a secondary separation on the liquid phase substance obtained by the primary separation to obtain an organic extract.

8. The method for extracting oily sludge according to claim 7, characterized in that: In step S3, supercritical carbon dioxide is continuously injected.

9. The method for extracting oily sludge according to claim 7, characterized in that: In step S4, the primary separation method is centrifugal separation, and the secondary separation method is low-temperature coagulation separation.

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