Oil sludge treatment process and equipment

Abstract

The present application specifically provides a sludge treatment process and equipment, and the sludge treatment process includes: pretreatment, uniformly mixing the sludge; rotary cavitation, stirring the pretreated sludge at high speed through a rotary cavitation device, so that the bubbles generated in the sludge split after approaching the inner wall of the rotary cavitation device, and the released energy destroys the combination of oil, mud and water, so that the sludge and water particles are redispersed; jet cavitation, spraying the sludge after rotary cavitation through a jet cavitation device; solid-liquid separation, the sludge after rotary cavitation is separated into solid and liquid phases through a solid-liquid separation device. The rotary cavitation and jet cavitation in the sludge treatment process can effectively destroy the combination of oil, mud and water by physical means, so that the solid-liquid separation process separates the solid tailings with low oil content.

Description

Technical Field

[0001] The present application relates to the technical field of oil sludge treatment, and in particular to an oil sludge treatment process and equipment. Background Art

[0002] Oil sludge is an oily solid waste generated during oil extraction, transportation, refining and oily wastewater treatment. It belongs to HW08 hazardous waste in the hazardous waste management catalog and is one of the main pollutants generated during oil and gas development and storage and transportation. Oil sludge is both a waste generated during oil field production and a resource. If the oil sludge is not treated and the oil in it is not recovered, it will not only waste resources but also pollute the environment. With the country's increasing attention to environmental protection and the continuous strengthening of environmental protection law enforcement, oil sludge has gradually become one of the environmental problems that need to be addressed.

[0003] The current treatment method for oil sludge is mostly on-site oil recovery, conditioning and adding chemicals. The treatment cost is high, and the solid tailings after treatment have a high oil content, generally 5%-10%, which is difficult to meet landfill requirements. Summary of the invention

[0004] In order to solve the technical problems of high cost and high oil content in solid tailings of current sludge treatment methods, the present application provides a sludge treatment process and equipment.

[0005] In the first aspect, the oil sludge treatment process provided in the present application comprises:

[0006] Pretreatment, mixing the sludge evenly;

[0007] Rotary cavitation: The pre-treated sludge is stirred at high speed by a rotary cavitation device, so that the energy released when the bubbles generated in the sludge break up after approaching the inner wall of the rotary cavitation device destroys the combination of oil, sludge and water, and redisperses the sludge water particles;

[0008] Jet cavitation, performing jet cavitation on the oil sludge after the rotational cavitation by means of a jet cavitation device;

[0009] Solid-liquid separation: the sludge after rotary cavitation is separated into solid and liquid phases through a solid-liquid separation device.

[0010] In one embodiment of the present disclosure, the jet cavitation device includes a multi-hole venturi tube and a single-hole venturi tube. In the jet cavitation, the oil sludge is sprayed through the multi-hole venturi tube and then enters the single-hole venturi tube for spraying again.

[0011] In one embodiment of the present disclosure, in the jet cavitation, the oil sludge enters from the diffuser section and is ejected from the contraction section of the multi-hole venturi tube, and enters from the contraction section and is ejected from the diffuser section of the single-hole venturi tube.

[0012] In one embodiment of the present disclosure, the solid phase separated by the solid-liquid separation device is tested, and the solid phase that does not meet the qualified standard is re-submitted to the pretreatment, the rotary cavitation and the solid-liquid separation.

[0013] In one embodiment of the present disclosure, the qualification standard of the solid phase separated by the solid-liquid separation device is oil content ≤ 0.3%.

[0014] In one embodiment of the present disclosure, before or during the pretreatment, the method further includes adding water to the oil sludge so that the solid phase of the oil sludge accounts for 15%-30% of the total volume of the oil sludge.

[0015] In one embodiment of the present disclosure, hot water is added to the oil sludge to make part of the oil in the oil sludge float to the upper layer, and then the floating oil in the upper layer is removed.

[0016] In one embodiment of the present disclosure, in the rotational cavitation, the volume proportion of bubbles in the sludge is between 20% and 30%.

[0017] In one embodiment of the present disclosure, in the rotational cavitation, the volume proportion of bubbles in the sludge is between 30% and 50%.

[0018] In one embodiment of the present disclosure, in the rotational cavitation, the volume proportion of bubbles in the sludge is between 50% and 70%.

[0019] In one embodiment of the present disclosure, the sludge treatment process also includes oil-water separation, and the liquid phase after solid-liquid separation is subjected to oil-water separation through a sewage treatment system. The water separated by the sewage treatment system is transported to the sludge to be pretreated to adjust the solid phase ratio of the sludge to be pretreated.

[0020] In one embodiment of the present disclosure, the sewage treatment system comprises a heating device for heating the separated water to 75-85 degrees before being transported to the oil sludge to be pre-treated.

[0021] In a second aspect, the oil sludge treatment equipment provided by the present application is applicable to the above-mentioned oil sludge treatment process, and the oil sludge treatment equipment comprises:

[0022] A pretreatment separation device, wherein the pretreatment separation device is used to uniformly mix the oil sludge;

[0023] A rotary cavitation device, which is connected to the pre-treatment separation device and is used to stir the oil sludge treated by the pre-treatment separation device at a high speed, so that the bubbles generated in the oil sludge are split after approaching the inner wall of the rotary cavitation device, and the released energy destroys the combination between the oil, sludge and water, so that the oil sludge and water particles are redispersed;

[0024] a jet cavitation device, the jet cavitation device comprising a venturi tube in communication with the rotary cavitation device, the venturi tube being configured to spray oil sludge;

[0025] A solid-liquid separation device is connected to the jet cavitation device and is used to separate the oil sludge treated by the jet cavitation device into a solid phase and a liquid phase.

[0026] In one embodiment of the present disclosure, the jet cavitation device comprises:

[0027] aisle;

[0028] a multi-porous venturi tube, the multi-porous venturi tube being disposed in the passage and comprising a plurality of venturi through holes;

[0029] a single-hole venturi tube, the single-hole venturi tube being disposed in the passage;

[0030] The oil sludge is configured to be ejected through the multiple Venturi through holes of the multi-hole Venturi tube and then enter the single-hole Venturi tube to be ejected again.

[0031] In one embodiment of the present disclosure, the sludge entering the jet cavitation device is configured to: enter from the diffuser section of the multiple Venturi holes and be ejected from the contraction section; enter from the contraction section of the single-hole Venturi tube and be ejected from the diffuser section.

[0032] In one embodiment of the present disclosure, the solid-liquid separation device is connected to the pre-treatment separation device, and the solid phase that does not meet the qualified standards separated by the solid-liquid separation device is transported to the pre-treatment separation device.

[0033] In one embodiment of the present disclosure, the oil sludge treatment equipment further includes a sewage treatment system, which is connected to the solid-liquid separation device and is used to separate oil and water from the liquid phase separated by the solid-liquid separation device.

[0034] In one embodiment of the present disclosure, the sewage treatment system is connected to the pretreatment separation device and / or the rotary cavitation device and / or the jet cavitation device, and the separated water is transported to the pretreatment separation device and / or the rotary cavitation device and / or the jet cavitation device.

[0035] In one embodiment of the present disclosure, the sewage treatment system comprises a heating device for heating water separated by the sewage treatment system.

[0036] In the oil sludge treatment process and equipment of the present application, the oil sludge is firstly mixed uniformly by a pretreatment separation device in a pretreatment step, and the oil sludge is stirred at a high speed in a rotary cavitation step. Under the action of high-speed physical crushing, supercritical water dissolution and hydration thermal cracking, the combination of oil, mud and water can be destroyed. The oil sludge is sprayed in the spray cavitation step, and the solid phase and the liquid phase are separated in the solid-liquid separation step. The separated solid phase has a low oil content, and the separated liquid phase can be reused. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flow chart of an oil sludge treatment process provided by an embodiment of the present application;

[0038] Figure 2 It is a schematic diagram of the principle of an oil sludge treatment device provided in one embodiment of the present application;

[0039] Figure 3 This is a schematic diagram of the overall device of the oil sludge treatment equipment provided in one embodiment of the present application;

[0040] Figure 4 is a cross-sectional view of a jet cavitation device in an oil sludge treatment device provided in an embodiment of the present application;

[0041] Figure 5 It is a schematic diagram of the structure of a multi-hole venturi tube in an oil sludge treatment device provided in one embodiment of the present application.

[0042] Figures 1 to 5 The one-to-one correspondence between the component names and the reference numerals is as follows:

[0043] 1. Pretreatment separation device; 11. Feeding device; 2. Rotary cavitation device; 3. Jet cavitation device; 31. Channel; 32. Multi-hole Venturi tube; 321. Venturi through hole; 33. Single-hole Venturi tube; 34. Water inlet; 4. Solid-liquid separation device; 41. Conveying device; 5. Sewage treatment system; 51. Flotation device; 52. Heating device; 53. First water storage tank; 54. Second water storage tank. DETAILED DESCRIPTION

[0044] In order to make the invention purpose, technical solution and beneficial technical effect of the present application clearer, the present application is described in detail below in conjunction with specific embodiments. It should be understood that the embodiments described in this specification are only for explaining the present application, not for limiting the present application.

[0045] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unambiguous range; and any lower limit can be combined with other lower limits to form an unambiguous range, and any upper limit can be combined with any other upper limit to form an unambiguous range. In addition, although not explicitly stated, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined as its own lower limit or upper limit with any other point or single value or with other lower limits or upper limits to form an unambiguous range.

[0046] The above-mentioned summary of the invention of the present application is not intended to describe each disclosed embodiment or each implementation in the present application. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided by a series of examples, which can be used in various combinations. In each example, enumeration is only used as a representative group and should not be interpreted as exhaustive.

[0047] First, the terms involved in the embodiments of the present application are explained.

[0048] Petroleum refers to a mixture of gaseous, liquid and solid hydrocarbons in natural states. Petroleum is divided into crude oil, natural gas, natural gas liquid and natural tar, but it is customary to use "petroleum" as the definition of "crude oil". Crude oil is a dark brown viscous oily liquid with green fluorescence and a special smell. It is a mixture of various liquid hydrocarbons such as alkanes, cycloalkanes, aromatic hydrocarbons and olefins.

[0049] Oil sludge: Oil sludge is mostly a mixture of water, mud or mud sand, oil and other impurities. It is an oil-containing waste generated during the process of oil extraction, transportation, and refining. According to the formation of oil sludge, it can usually be divided into ground oil sludge, tank cleaning oil sludge, aged oil sludge, etc.

[0050] Oil sludge: During the oil well production and downhole operation, some crude oil is released or carried to the land or well site by oil pipes, sucker rods, pumps and other downhole tools. These crude oils seep into the ground soil and form oil sludge. Oil sludge has the characteristics of high solid content and many types of impurities.

[0051] Tank cleaning sludge (also called warehouse cleaning sludge): It has a high oil content and a high heavy component content. The crude oil and sludge are tightly adsorbed and are not easy to separate. Tank cleaning sludge is mainly divided into two categories: one is produced during the treatment of oil production wastewater. Due to the fine particles, sediment, etc. contained in the wastewater itself, and the specific gravity of the colloid asphaltene and heavy metals in the middle reaches of the river, a small amount of crude oil sinks to the bottom of the oil storage tank, thereby forming black, fine-grained, and oil-rich sludge; the second is produced when using oil storage tanks to store crude oil. When storing oil products, especially crude oil, after a long period of storage, a small amount of mechanical impurities, sand, soil, heavy metals, and heavy oil components such as paraffin asphaltene in the oil products will naturally settle due to the specific gravity difference, and accumulate at the bottom of the oil tank to form a black and thick colloid-like substance.

[0052] Aged sludge: Aged sludge is formed when sludge is not treated for a long time after it is produced. It is obviously oxidized, has a high content of heavy components, is complex in composition, and is difficult to pretreat.

[0053] Oil sands are sandstone or other rocks containing natural asphalt or tar. They are usually a mixture of sand, asphalt, minerals, clay and water. After mining, extraction, separation and modification, synthetic crude oil can be obtained. Synthetic crude oil can be made into various finished oils and petroleum products through smelting and processing.

[0054] Supercritical water: refers to water when the air pressure and temperature reach a certain value, and the density of water expanded by high temperature is exactly the same as the density of water vapor compressed by high pressure. At this time, there is no difference between the liquid and gas of water, and they are completely blended together to become a new fluid with high pressure and high temperature.

[0055] Hydration heat: refers to the heat released when a substance combines with water. This thermal effect is often not simply caused by hydration, so other names are sometimes used.

[0056] The present application provides a sludge treatment process, such as Figure 1 and Figure 2 As shown, the following steps are included:

[0057] Pretreatment, mixing the sludge evenly;

[0058] Rotary cavitation: The pre-treated sludge is stirred at high speed by a rotary cavitation device 2, so that the energy released by the bubbles generated in the sludge during the splitting breaks the bond between the oil, sludge and water, and the sludge water particles are redispersed;

[0059] Jet cavitation, performing jet cavitation on the oil sludge after the rotation cavitation by means of a jet cavitation device 3;

[0060] Solid-liquid separation: the oil sludge after rotary cavitation is separated into a solid phase and a liquid phase through a solid-liquid separation device 4 .

[0061] The oil sludge treatment process uses two cavitation treatments: rotary cavitation and jet cavitation. Among them, the role of rotary cavitation is to fully evenly and crush the three-phase mixed medium of oil, sludge and water, so that the oil sludge undergoes preliminary cavitation and preliminary separation. The role of jet cavitation is to further crush the mixed medium after rotary cavitation, so that the oil sludge and water particles in a tightly combined state can be separated, which belongs to deep cavitation and further separation. Rotary cavitation and jet cavitation fully crush and disperse the oil sludge particles that combine oil, water and mud, effectively improving the separation efficiency of the solid and liquid phases in the oil sludge.

[0062] In one embodiment of the present disclosure, the pretreatment step can be achieved by a pretreatment separation device 1, which includes a stirring device to transport the sludge to be treated to the stirring device for uniform stirring. There are many types of sludge to be treated, and their water content, oil content and the degree of combination of oil, mud and water are different. When the solid content in the sludge is too high, the sludge is too viscous and not easy to stir evenly, which affects the separation effect. In this regard, before or during pretreatment, a step of adding water to the sludge can also be included. For the sludge to be treated with a solid content exceeding 30%, the solid content in the sludge is reduced to 15%-30% by adding water, so as to facilitate the stirring device to stir the sludge evenly and facilitate rotary cavitation. The stirring device can include a motor and a stirring paddle, and the motor drives the stirring paddle to rotate to stir the sludge. Of course, those skilled in the art can also use other conventional stirring devices.

[0063] In one embodiment of the present disclosure, Figure 3 As shown, the pretreatment separation device 1 also includes a feeding device 11 and a cleaning device. Before stirring, the sludge is first transported to the cleaning device through the feeding device 11. The feeding device 11 can adopt a screw conveyor, a conveyor belt conveyor or other devices. Then water is added to the sludge in the cleaning device. After adding water, the free oil in the sludge can float on the upper layer. The upper part of the cleaning device is provided with an oil overflow port, and the floating oil on the upper layer of the cleaning device can flow out from the oil overflow port, thereby removing part of the oil in the sludge.

[0064] In a specific embodiment of the present disclosure, the water added to the sludge in the cleaning device can be hot water, and the temperature of the hot water can be controlled between 75-85°C. The solidification point of conventional crude oil is usually lower than 40°C. When the temperature is too low, the crude oil is in a solidified state and has poor fluidity. Adding hot water to the sludge can increase the temperature of the sludge, increase the fluidity of the oil, and make it easier to separate the crude oil in a flowing state. The crude oil in a flowing state in the sludge can float on the upper layer, which is conducive to removing the floating oil on the upper layer. Preferably, the temperature of the hot water is controlled at 80°C. According to experimental tests, the pretreatment effect is best when the water temperature is around 80°C, which can ensure that the crude oil has good fluidity and low energy consumption.

[0065] In one embodiment of the present disclosure, the rotary cavitation device 2 includes a container, and the container is used to stir the oil sludge at high speed. A plurality of hydraulic orifice plates can be arranged in the container, and the inner wall of the rotary cavitation device 2 includes the inner surface of the container and the surface of the hydraulic orifice plates. The hydraulic orifice plates can increase the area of ​​the inner wall of the rotary cavitation device 2, thereby achieving the purpose of hydraulic cavitation. The rotary cavitation device 2 also includes a power device, which can be connected to the container to drive the container to rotate at high speed, thereby stirring the oil sludge in the container. The power device can also be connected to at least part of the hydraulic orifice plates to drive at least part of the hydraulic orifice plates to rotate, thereby stirring the oil sludge.

[0066] After the sludge is stirred at high speed in the container, local instantaneous negative pressure is formed in certain areas of the container, thereby generating a large number of bubbles. When the bubbles approach the inner wall of the container or the surface of the hydraulic orifice plate to a distance less than the initial radius of the bubbles, the speed of the microjet impacting the inner wall of the container and the surface of the hydraulic orifice plate can reach 1000m / s. The bubbles further split into smaller bubbles. When the bubbles split, the microjet squeezes and produces an implosion, releasing energy instantly, and can emit high-frequency and large-amplitude pressure waves with a pressure of up to 1.01×10 4 KPa to 1.01×10 5 KPa, local temperature can reach 10 4 ℃, duration 2 to 3μs. The high-speed physical crushing effect of the rotating cavitation device 2 on the oil sludge by high-speed stirring can break the original binding film between the oil and fine sand particles, destroy the state of water-in-oil and oil-in-water, and redisperse the oil sludge water particles.

[0067] Under the conditions of high temperature and high pressure, the surface water of bubbles in the oil sludge becomes supercritical water, which has an oxidizing effect and is conducive to dissolving and peeling the oil film on the surface of the particles. The oil sludge also undergoes hydration and thermal cracking in the rotary cavitation device 2, which can crack macromolecular substances such as asphalt in the oil sludge into small molecular substances. Under the high-speed physical crushing effect, supercritical water dissolution effect and hydration and thermal cracking effect of the rotary cavitation device 2, the combination between oil, mud and water can be destroyed, and the three-phase separation can be effectively achieved. Rotary cavitation uses a physical method to separate the oil sludge. No reagents are added during the solid-liquid separation process, and the separation effect is sufficient.

[0068] The rotary cavitation process of the rotary cavitation device 2 can be divided into three types according to the amount of bubble generation: primary cavitation, intermediate cavitation and super cavitation, and can be applied to different types of sludge, such as ground sludge, tank cleaning sludge and aged sludge. Different types of sludge are recommended to adopt different rotary cavitation processes based on their solid content, heavy component ratio and median particle size range, as shown in Table 1 below.

[0069]

[0070] Table 1

[0071] Those skilled in the art can determine the type of sludge (ground sludge, tank cleaning sludge, aged sludge) by testing the four components of the oil phase of the sludge, and select the corresponding treatment methods (primary cavitation, intermediate cavitation and super cavitation). The four components of the oil phase include: saturated fraction / %, aromatic fraction / %, colloid / %, and asphaltene / %. Different types of sludge have different proportions of the four phases.

[0072] In Table 1, heavy components refer to propane and components with molecular weight greater than propane in crude oil, which are black or dark brown, heavy oil, high relative density on the ground, high viscosity, high wax content, high initial distillation point, high freezing point, high content of colloid and asphaltene, low fraction, low gas-oil ratio, etc. Oil sludge contains many heavy components and is not easy to separate.

[0073] Particle size is used to indicate the particle size of sludge particles, that is, the size of sludge particles. The particle size here is not the actual diameter of the particle, but a virtual "equivalent diameter". The equivalent diameter is when a physical property of the measured particle is closest to a homogeneous sphere of a certain diameter, the diameter of the sphere is taken as the equivalent diameter of the measured particle.

[0074] D50 refers to the particle size corresponding to when the cumulative particle size distribution percentage of a sample reaches 50%. Its physical meaning is that particles with a particle size larger than it account for 50%, and particles with a particle size smaller than it also account for 50%. D50 is also called the median diameter or median particle size. D50 is often used to indicate the average particle size of powders.

[0075] As can be seen from Table 1, the solid content of the fallen sludge is greater than 20%, the proportion of heavy components is ≤2%, and the median particle size D50 of the sludge particles is greater than 20um, so the primary cavitation process can be used for treatment.

[0076] The solid content of tank cleaning sludge is ≤20%, and the proportion of heavy components is between 2-10%. For tank cleaning sludge with heavy components ≤20% and a median particle size D50>20um, the primary cavitation process can be used for treatment; for tank cleaning sludge with heavy components between 2-10% and a median particle size D50>20um, the intermediate cavitation process can be used for treatment; for tank cleaning sludge with heavy components>10% and a median particle size D50<20um, the super cavitation process can be used for treatment.

[0077] The solid content of the aged sludge on the ground is greater than 35%, the proportion of heavy components is greater than 20%, and the median particle size D50 of the sludge particles is less than 20um. It can be treated by super cavitation process.

[0078] The bubble volume proportion, sludge crushing particle size, oil-solid separation form and applicable sludge type of the three types of primary cavitation, intermediate cavitation and super cavitation of the rotary cavitation process are shown in Table 2 below.

[0079] Dispersed categories Primary cavitation Intermediate Cavitation Super Cavitation Bubble volume ratio / % 20-30 30-50 50-70 Oil sludge crushing particle size / μm ≥5 1-5 ≤1 Oil-solid separation form Surface peeling Crushing + emulsification Lysis + emulsification Applicable materials Oil sands, oil sludge, etc. Tank cleaning, oil sludge, etc. Aged sludge, oil-based drilling cuttings, etc.

[0080] Table 2

[0081] As shown in Table 2, in the primary cavitation process, the bubble volume accounts for 20-30%, which is used to break up oil sludge particles with a particle size of ≥5μm, and can peel off the oil film on the surface of solid particles. It is suitable for ground oil sludge with a relatively light combination of oil, mud and water. Primary cavitation can also be used to treat oil sands.

[0082] In the intermediate cavitation process, the bubble volume accounts for 30-50%, which is used to crush sludge particles with a particle size between 1-5μm. It can crush and emulsify solid particles and is suitable for tank cleaning sludge such as tank bottom sludge with a relatively high degree of combination of oil, mud and water.

[0083] In the super cavitation process, the bubble volume accounts for 50-70%, which is used to crush sludge particles with a particle size of ≤1μm, and can crack and emulsify solid particles. It is suitable for aged sludge and oil-based drill cuttings with the highest degree of combination of oil, mud and water.

[0084] In one embodiment of the present disclosure, Figure 2 , Figure 3 As shown, the jet cavitation device 3 is connected with the rotary cavitation device 2 and the solid-liquid separation device 4. The oil sludge after rotary cavitation enters the jet cavitation device 3 for jet cavitation and then is transported from the jet cavitation device 3 to the solid-liquid separation device 4. The jet cavitation device 3 includes a venturi tube, which is configured to spray the oil sludge.

[0085] The venturi tube includes a contraction section, a throat section and a diffusion section which are connected in sequence. Normally, the fluid enters the throat section from the contraction section, then enters the diffusion section and is ejected. Both the contraction section and the diffusion section are conical tubes, and the taper of the diffusion section is smaller than that of the contraction section. The diffusion section can gradually decelerate the fluid relatively slowly, reduce the turbulence of the fluid, and thus reduce energy loss. The specific structure and principle of the venturi tube are prior arts known in the art. When the oil sludge is ejected from the venturi tube, the pressure is instantly reduced and the speed is increased, and the strong shock wave generated causes the water in the oily sludge to be vaporized and broken instantly, breaking the binding force between hydrocarbons (oil) and solids, so that the oil can be extracted from the mud.

[0086] In one embodiment of the present disclosure, the jet cavitation device 3 includes a porous venturi tube 32 and a single-hole venturi tube 33 that are interconnected, the porous venturi tube 32 is connected to the rotary cavitation device 2, and the single-hole venturi tube 33 is connected to the solid-liquid separation device 4. In jet cavitation, the sludge first enters the porous venturi tube 32 and is sprayed, and then enters the single-hole venturi tube 33 and is sprayed again. In jet cavitation, the sludge after rotary cavitation is sprayed through the porous venturi tube 32, and the structure of the sludge water particles is further cavitated and broken. The single-hole venturi tube 33 can homogenize and decelerate the sludge after spray cavitation by the porous venturi tube 32.

[0087] Specifically, Figure 4 , Figure 5 As shown, the jet cavitation device 3 includes a channel 31, and a multi-hole venturi tube 32 and a single-hole venturi tube 33 are arranged in the channel 31. A plurality of venturi holes 321 for oil sludge to pass through are distributed on the multi-hole venturi tube 32, and the extension direction of the plurality of venturi holes 321 is consistent. Each venturi hole 321 includes a throat section, a contraction section and a diffusion section, and the taper of the contraction section is smaller than the taper of the diffusion section. After the oil sludge after rotary cavitation is transported to the jet cavitation device 3, it enters the multi-hole venturi tube 32 and is ejected from the plurality of venturi holes 321. The single-hole venturi tube 33 also includes a throat section, a contraction section and a diffusion section, and the taper of the contraction section is smaller than the taper of the diffusion section. The oil sludge ejected through the venturi hole 321 can enter the single-hole venturi tube 33 along the channel 31, ejected through the single-hole venturi tube 33, and then transported to the solid-liquid separation device 4.

[0088] The venturi tube can be used in an upright or inverted position. When used in an upright position, the fluid enters the throat section from the contraction section of the venturi tube and then sprays out from the diffusion section. When used in an inverted position, the fluid enters the throat section from the diffusion section of the venturi tube and then sprays out from the contraction section.

[0089] In one embodiment of the present disclosure, the venturi through hole 321 of the multi-hole venturi tube 32 and the single-hole venturi tube 33 are both arranged in a positive manner in the channel 31. The diffusion section of the venturi through hole 321 is directly opposite to the contraction section of the single-hole venturi tube 33, and the sludge enters from the contraction section of the venturi through hole 321 and is sprayed out from the diffusion section, and then enters from the contraction section of the single-hole venturi tube 33 and is sprayed out from the diffusion section.

[0090] In another embodiment of the present disclosure, Figure 4 , Figure 5As shown, the Venturi through hole 321 of the multi-hole Venturi tube 32 is arranged in an inverted manner in the channel 31, and the single-hole Venturi tube 33 is arranged in an upright manner in the channel 31. The contraction section of the Venturi through hole 321 is directly opposite to the contraction section of the single-hole Venturi tube 33, and the sludge enters from the diffusion section of the Venturi through hole 321 and sprays out from the contraction section, and then enters from the contraction section of the single-hole Venturi tube 33 and sprays out from the diffusion section. The inverted arrangement of the Venturi through hole 321 makes the sludge faster and less pressure when spraying, and makes the pressure of the sludge change dramatically after entering the contraction section of the single-hole Venturi tube 33, which is conducive to improving the cavitation effect and fully breaking and dispersing the sludge particles.

[0091] The porous venturi tube 32 and the single-hole venturi tube 33 of the jet cavitation device 3 spray the oil sludge twice to fully disperse the oil sludge, which is conducive to the full generation of bubbles. The collapse of the bubbles impacts the oil sludge, further breaking and dispersing the oil sludge particles combined with oil, mud and water.

[0092] In the sludge treatment process, water can be fed into the jet cavitation device 3 to dilute the sludge so that the sludge particles can be dispersed in the water, and the pressure of the sludge can be increased, which is conducive to more sufficient crushing and dispersion of the sludge during jet cavitation. Specifically, a water inlet 34 can be set on the channel 31 of the jet cavitation device 3, and water is supplied to the sludge in the jet cavitation device 3 through the water inlet 34. The water inlet 34 can be set between the jet cavitation device 3 and the rotary cavitation device 2 to supply water to the sludge before jet cavitation; or, the water inlet 34 can also be set at a position between the single-hole venturi tube 33 and the multi-hole venturi tube 32 to supply water to the sludge during the jet cavitation process, in order to adjust the operating pressure of the medium in the venturi tube.

[0093] In a specific embodiment of the present disclosure, Figure 4 As shown, the channel 31 of the jet cavitation device 3 adopts a three-way pipe, and the three-way pipe has an A port, a B port and a C port, wherein a multi-hole venturi tube 32 is arranged in the A port, a single-hole venturi tube 33 is arranged in the B port, and the C port serves as a water inlet 34. The A, B, and C ports are configured into a T-shaped structure, and the A port provided with the multi-hole venturi tube 32 and the B port provided with the single-hole venturi tube 33 are arranged to extend on the same straight line to reduce the obstruction to the oil sludge and reduce the kinetic energy loss of the oil sludge.

[0094] In one embodiment of the present disclosure, the solid-liquid separation device 4 is configured to separate the oil sludge after jet cavitation into a solid phase and a liquid phase. The solid phase separated by the solid-liquid separation device 4 is tested, and the qualified standard of the solid phase is that the oil content does not exceed 0.3%. The qualified solid phase can meet the required indicators of agricultural soil and can be directly discharged or further processed and utilized, such as burning bricks, paving roads, etc. The solid phase separated by the solid-liquid separation device 4 that does not meet the qualified standards can be transported back to the pretreatment separation device 1, and rotary cavitation, jet cavitation and solid-liquid separation are performed again.

[0095] The solid-liquid separation device 4 can be a horizontal spiral centrifuge, which separates the solid phase and the liquid phase by centrifugal action. Specifically, the unqualified solid phase separated by the horizontal spiral centrifuge can be transported to the cleaning device of the pretreatment separation device 1 through the conveying device 41, and the conveying device 41 can be a screw conveyor. This part of the unqualified solid phase can be mixed with new sludge to be treated, or it can be separately entered into the pretreatment system to re-perform the pretreatment, rotary cavitation and solid-liquid separation process until it reaches the qualified standard.

[0096] The sludge treatment process also includes an oil-water separation step, and the liquid phase after solid-liquid separation is separated into oil and water by a sewage treatment system 5. The sewage treatment system 5 includes an air flotation device 51, which further separates the liquid phase separated in the solid-liquid separation step into oil and water. The separated water can be heated by a heating device 52 and then transported to the pretreatment separation device 1 to adjust the solid phase content of the sludge in the pretreatment separation device 1 for recycling. The sewage treatment system 5 can provide power to the liquid through a power device such as an impeller pump.

[0097] In the oil sludge treatment process of the present application, the oil content of the solid phase separated in the solid-liquid separation process reaches ≤0.3%, which is much better than the current oil sludge treatment method; no chemicals need to be added during the rotary cavitation, jet cavitation and solid-liquid separation process, and the cost is low. The water separated in the oil-water separation process can be recycled, which is more environmentally friendly; the entire process is relatively simple and the work efficiency is high. In addition, the entire treatment process of the oil sludge treatment process can be completed at room temperature or slightly above room temperature, with low energy consumption, and there is a step of adding hot water in the pretreatment process, which can treat frozen oil sludge, solving the current problem that oil sludge cannot be treated in winter.

[0098] The present application also provides an oil sludge treatment device, which is suitable for the above-mentioned oil sludge treatment process. Figure 2 , Figure 3 As shown, the oil sludge treatment equipment mainly includes a pretreatment separation device 1, a rotary cavitation device 2 and a solid-liquid separation device 4.

[0099] Among them, the pretreatment separation device 1 is used to carry out the pretreatment step of the sludge treatment process to evenly mix the sludge; the rotary cavitation device 2 is connected to the pretreatment separation device 1, and is used to high-speed stir the sludge treated by the pretreatment separation device 1. The rotary cavitation device 2 includes a container and a plurality of hydraulic orifice plates located in the container. The sludge is stirred at a high speed until the bubbles generated in the sludge split after approaching the inner wall of the container or the surface of the hydraulic orifice plate. The released energy destroys the combination of oil, mud and water, and redisperses the sludge water particles; the solid-liquid separation device 4 is connected to the rotary cavitation device 2, and is used to separate the sludge treated by the rotary cavitation device 2 into a solid phase and a liquid phase.

[0100] like Figure 2 As shown, the oil sludge treatment equipment also includes a jet cavitation device 3 arranged between the rotary cavitation device 2 and the solid-liquid separation device 4, and the jet cavitation device 3 is used for jet cavitation. The jet cavitation device 3 includes a venturi tube, and the venturi tube is configured to spray oil sludge. The oil sludge sprayed by the jet cavitation device 3 is transported to the solid-liquid separation device 4.

[0101] In one embodiment of the present disclosure, Figure 2 As shown, the pretreatment separation device 1 may include a feeding device 11, a cleaning device and a stirring device connected in sequence. The feeding device 11 includes but is not limited to a screw conveyor, a belt conveyor, etc., which transports the oil sludge to be treated to the cleaning device. The cleaning device has a cavity for accommodating the oil sludge, and the upper part of the cleaning device has an oil overflow port connected to the cavity. Water can be added to the cavity of the cleaning device so that the free oil in the oil sludge can float on the upper layer. After the liquid level reaches the oil overflow port, the floating oil in the upper layer can flow out from the oil overflow port, thereby removing part of the oil in the oil sludge. Adding water to the oil sludge can also adjust the solid phase content of the oil sludge. The oil sludge in the cleaning device further enters the stirring device, and the stirring device stirs the oil sludge evenly.

[0102] In one embodiment of the present disclosure, the container of the rotary cavitation device 2 is used to stir the oil sludge, and a plurality of hydraulic orifice plates can be arranged on the inner wall of the container. After the oil sludge is stirred at high speed, a large number of bubbles are generated. When the bubbles approach the inner wall of the container or the surface of the hydraulic orifice plate to a distance less than the initial radius of the bubble, they split and release energy, producing high-speed physical crushing, supercritical water dissolution and hydration thermal cracking effects on the oil sludge. The three effects can destroy the combination of oil, mud and water, and effectively achieve three-phase separation of the oil sludge. The setting of the hydraulic orifice plate can increase the surface area that collides with the bubbles, thereby improving the working efficiency of the rotary cavitation device 2.

[0103] In one embodiment of the present disclosure, Figure 2 , Figure 3As shown, the solid-liquid separation device 4 is connected to the pretreatment separation device 1, and the solid phase separated by the solid-liquid separation device 4 that does not meet the qualified standard is transported to the pretreatment separation device 1 for pretreatment again, and then transported to the rotary cavitation device 2, the jet cavitation device 3 and the solid-liquid separation device 4 for treatment. The unqualified solid phase can be repeated several times through the above process until the solid phase separated by the solid-liquid separation device 4 meets the qualified standard. Specifically, the solid-liquid separation device 4 can use a horizontal spiral centrifuge, which is connected to the pretreatment separation device 1 to separate the pretreated sludge into a solid phase and a liquid phase. The qualified standard of the solid phase separated by the solid-liquid separation device 4 can be limited to an oil content of no more than 0.3%, and the solid phase that does not meet the qualified standard is transported back to the pretreatment separation device 1. The solid-liquid separation device 4 can also use other types of equipment, such as a butterfly centrifuge, as long as the sludge can be separated into a solid phase and a liquid phase.

[0104] The solid-liquid separation device 4 can be connected to the cleaning device in the pretreatment separation device 1 through a conveying device 41, and the unqualified solid phase is transported to the cleaning device through the conveying device 41. The conveying device 41 is not limited to a screw conveyor, a belt conveyor, etc.

[0105] In one embodiment of the present disclosure, the solid-liquid separation device 4 can be a three-phase horizontal spiral centrifuge, which can perform three-phase separation of oil sludge with high oil content through centrifugal action to separate oil, water and solid phases. In another embodiment, when the oil content of the sludge is relatively low, a two-phase horizontal spiral centrifuge can also be used to separate the sludge into a solid phase and a liquid phase.

[0106] In one embodiment of the present disclosure, Figure 2 , Figure 3 As shown, the oil sludge treatment equipment also includes a sewage treatment system 5, which is connected to the solid-liquid separation device 4 and is used to separate oil and water from the liquid phase separated by the solid-liquid separation device 4. When the solid-liquid separation device 4 is a three-phase horizontal spiral centrifuge, the three-phase horizontal spiral centrifuge transports the separated water to the sewage treatment system for further oil-water separation treatment. Specifically, the sewage treatment system 5 includes an air flotation device 51, which is connected to the horizontal spiral centrifuge, and the liquid phase separated by the horizontal spiral centrifuge is further separated into oil and water.

[0107] In one embodiment of the present disclosure, the sewage treatment system 5 can be further connected to the pretreatment separation device 1 to transport the separated water to the pretreatment separation device 1 for recycling. Specifically, the flotation device 51 is connected to the cleaning device of the pretreatment separation device 1.

[0108] In one embodiment of the present disclosure, the sewage treatment system 5 can be further connected to the rotary cavitation device 2 to transport the separated water to the rotary cavitation device 2 to adjust the solid-liquid content of the sludge in the rotary cavitation device 2. Specifically, the sewage treatment system 5 is connected to the container of the rotary cavitation device 2, and the water separated by the flotation device 51 is added to the container of the rotary cavitation device 2.

[0109] In one embodiment of the present disclosure, the sewage treatment system 5 can be further connected to the jet cavitation device 3 to transport the separated water to the jet cavitation device 3. Specifically, the air flotation device 51 is connected to the water inlet 34 of the jet cavitation device 3, and the separated water is added to the venturi tube to adjust the pressure.

[0110] In one embodiment of the present disclosure, the sewage treatment system 5 further includes a heating device 52, which is connected between the flotation device 51 and the pretreatment separation device 1, and can heat the water separated by the flotation device 51 before being transported to the pretreatment separation device 1, and heat the water to between 75-85°C, thereby improving the fluidity of the crude oil and facilitating the separation of the crude oil. Preferably, the heating device 52 can heat the water to 80 degrees, which can ensure that the crude oil has good fluidity and low energy consumption.

[0111] In one embodiment of the present disclosure, Figure 3 As shown, the sewage treatment system 5 further includes a first water tank 53 and a second water tank 54. The first water tank 53 is connected between the solid-liquid separation device 4 and the air flotation device 51. The liquid phase separated by the solid-liquid separation device 4 can be temporarily stored in the first water tank 53. The second water tank 54 is connected between the heating device 52 and the pretreatment separation device 1, and can temporarily store circulating hot water before entering the pretreatment separation device 1. The second water tank 54 is also connected to the rotary cavitation device 2 and the jet cavitation device 3, and water is supplied to the rotary cavitation device 2 and the jet cavitation device 3.

[0112] The oil sludge treatment equipment uses physical methods to treat oil sludge, does not need to add any chemicals, has low cost, and the oil content of the separated solid phase reaches ≤0.3%, which meets the required indicators of agricultural soil. The pretreatment separation device 1, the rotary cavitation device 2, the jet cavitation device 3, the solid-liquid separation device 4 and the sewage treatment system 5 can form a closed treatment system without secondary pollution and emission of other harmful gases. In addition, the sewage treatment system 5 realizes circulating water, which is safe and environmentally friendly.

[0113] The sludge treatment equipment may also include a control unit, which controls the pretreatment separation device 1, the rotary cavitation device 2, the solid-liquid separation device 4, the sewage treatment system 5, etc. The control unit may include a PCL, which can remotely control the start and stop, and can also be operated on the spot, which is safe and convenient. Specifically, the control unit can control the loading of the feeding device 11 of the pretreatment separation device 1, and control the motor of the stirring device to stir the sludge. The control unit can control the power device of the rotary cavitation device 2 to work so that the container stirs the sludge at high speed. The control unit can control the operation of the horizontal spiral centrifuge to separate the solid phase and liquid phase of the sludge, and control the conveying device 41 to transport the unqualified solid phase to the pretreatment separation device. The control unit can also control the power device of the sewage treatment system 5, which can pump water to the pretreatment separation device 1 or the jet cavitation device 3.

[0114] Each device of the oil sludge treatment equipment can be designed to be skid-mounted and mobile. The pretreatment and separation device 1, rotary cavitation device 2, jet cavitation device 3, solid-liquid separation device 4 and sewage treatment system 5 of the oil sludge treatment equipment are arranged on a movable chassis for easy movement. Each device can be flexibly combined according to the state of the oil sludge on site to reduce the floor space, and can be treated at the source, reducing transportation costs and environmental impact.

[0115] The specific structure and principle of the oil sludge treatment equipment in the present disclosure can refer to the oil sludge treatment equipment introduced in the above-mentioned oil sludge treatment process, so it will not be introduced in detail.

[0116] Embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the marketplace, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein. The scope of the present invention is defined by the appended claims.

Claims

1. A sludge treatment process, characterized in that: include: Pretreatment, mixing the sludge evenly; Rotary cavitation, wherein the pre-treated sludge is stirred at high speed by a rotary cavitation device (2), so that the energy released by the bubbles generated in the sludge during the splitting breaks the bond between the oil, sludge and water, and the sludge and water particles are redispersed; Jet cavitation, wherein the oil sludge after the rotational cavitation is subjected to jet cavitation by a jet cavitation device (3), wherein the jet cavitation device (3) comprises a channel (31), a multi-hole venturi tube (32) and a single-hole venturi tube (33), wherein a water inlet (34) is provided on the channel (31), and water is supplied to the oil sludge in the jet cavitation device (3) through the water inlet (34). During the jet cavitation, the oil sludge is sprayed through the multi-hole venturi tube (32) and then enters the single-hole venturi tube (33) for spraying again, wherein the oil sludge enters from the diffusion section and sprays out from the contraction section of the multi-hole venturi tube (32), and enters from the contraction section and sprays out from the diffusion section of the single-hole venturi tube (33); Solid-liquid separation: the sludge after jet cavitation is separated into a solid phase and a liquid phase through a solid-liquid separation device (4).

2. The oil sludge treatment process according to claim 1, characterized in that: The solid phase separated by the solid-liquid separation device (4) is tested, and the solid phase that does not meet the qualified standard is re-submitted to the pretreatment, the rotary cavitation and the solid-liquid separation.

3. The oil sludge treatment process according to claim 2, characterized in that: The qualified standard of the solid phase separated by the solid-liquid separation device (4) is that the oil content is ≤ 0.3%.

4. The oil sludge treatment process according to claim 1, characterized in that: Before or during the pretreatment, the method further includes adding water to the sludge so that the solid phase of the sludge accounts for 15%-30% of the total volume of the sludge.

5. The oil sludge treatment process according to claim 4, characterized in that: Hot water is added to the sludge to make some of the oil in the sludge float to the upper layer, and then the floating oil on the upper layer is removed.

6. The oil sludge treatment process according to claim 1, characterized in that: In the rotational cavitation, the volume of bubbles in the sludge accounts for between 20% and 30%.

7. The oil sludge treatment process according to claim 1, characterized in that: In the rotational cavitation, the volume of bubbles in the sludge accounts for between 30% and 50%.

8. The oil sludge treatment process according to claim 1, characterized in that: In the rotational cavitation, the volume of bubbles in the sludge accounts for between 50% and 70%.

9. The oil sludge treatment process according to claim 1, characterized in that: The oil sludge treatment process also includes oil-water separation, wherein the liquid phase after solid-liquid separation is subjected to oil-water separation through a sewage treatment system (5), and the water separated by the sewage treatment system (5) is transported to the oil sludge to be pretreated to adjust the solid phase ratio of the oil sludge to be pretreated.

10. The oil sludge treatment process according to claim 9, characterized in that: The sewage treatment system (5) comprises a heating device (52) for heating the separated water to 75-85°C before being transported to the oil sludge to be pre-treated.

11. An oil sludge treatment device, characterized in that: Applicable to the oil sludge treatment process according to any one of claims 1 to 10, the oil sludge treatment equipment comprises: A pretreatment separation device (1), wherein the pretreatment separation device (1) is used to uniformly mix the oil sludge; A rotating cavitation device (2), the rotating cavitation device (2) being connected to the pretreatment separation device (1), and being used to stir the oil sludge treated by the pretreatment separation device (1) at a high speed, so that bubbles generated in the oil sludge are split after approaching the inner wall of the rotating cavitation device (2), and the released energy destroys the bond between the oil, sludge and water, so that the oil sludge and water particles are redispersed; A jet cavitation device (3), the jet cavitation device (3) comprising a venturi tube connected to the rotary cavitation device (2), the venturi tube being configured to spray oil sludge; A solid-liquid separation device (4), the solid-liquid separation device (4) being in communication with the jet cavitation device (3) and used for separating the oil sludge treated by the jet cavitation device (3) into a solid phase and a liquid phase.

12. The oil sludge treatment equipment according to claim 11, characterized in that: The jet cavitation device (3) comprises: Channel (31); A multi-porous venturi tube (32), the multi-porous venturi tube (32) being arranged in the channel (31) and comprising a plurality of venturi through holes (321); A single-hole venturi tube (33), wherein the single-hole venturi tube (33) is arranged in the channel (31); The oil sludge is configured to be ejected through the multiple Venturi through holes (321) of the multi-hole Venturi tube (32) and then enter the single-hole Venturi tube (33) to be ejected again.

13. The oil sludge treatment equipment according to claim 12, characterized in that: The oil sludge entering the jet cavitation device (3) is configured to: enter from the diffusion section of the plurality of Venturi through holes (321) and be ejected from the contraction section; enter from the contraction section of the single-hole Venturi tube (33) and be ejected from the diffusion section.

14. The oil sludge treatment equipment according to claim 11, characterized in that: The solid-liquid separation device (4) is in communication with the pretreatment separation device (1), and the solid phase that does not meet the qualified standard separated by the solid-liquid separation device (4) is transported to the pretreatment separation device (1).

15. The oil sludge processing equipment according to claim 11, characterized in that: The oil sludge treatment equipment further comprises a sewage treatment system (5), wherein the sewage treatment system (5) is in communication with the solid-liquid separation device (4) and is used for performing oil-water separation on the liquid phase separated by the solid-liquid separation device (4).

16. The oil sludge treatment equipment according to claim 15, characterized in that: The sewage treatment system (5) is connected to the pretreatment separation device (1) and / or the rotary cavitation device (2) and / or the jet cavitation device (3), and the separated water is transported to the pretreatment separation device (1) and / or the rotary cavitation device (2) and / or the jet cavitation device (3).

17. The oil sludge processing equipment according to claim 15, characterized in that: The sewage treatment system (5) comprises a heating device (52) for heating water separated by the sewage treatment system (5).

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