Supercritical carbon dioxide catalytic cracking slurry oil mixing system

Abstract

The application discloses a supercritical carbon dioxide catalytic cracking oil slurry mixing system, which comprises a horizontal tank body, a supercritical carbon dioxide inlet, an oil slurry inlet, a dispersion plate obliquely arranged in the horizontal tank body, a plurality of injection holes arranged on the dispersion plate, a settling cylinder arranged at the bottom of the horizontal tank body outside the right side of the dispersion plate, a mixture outlet arranged at the bottom of the settling cylinder, a supercritical carbon dioxide outlet arranged at the top right side of the horizontal tank body, a partition plate arranged on the inner wall of the horizontal tank body at the right side of the settling cylinder, and a light mixture outlet arranged on the outer wall of the horizontal tank body at the right side of the partition plate. The application overcomes the mixing difficulty problem caused by the large viscosity and poor flowability of the oil slurry, and realizes the full mixing of the oil slurry and the supercritical carbon dioxide.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of mixers, and particularly relates to a supercritical carbon dioxide catalytic cracking oil slurry mixing system. BACKGROUND

[0002] Catalytic cracking oil slurry contains a large amount of aromatic hydrocarbons and alkanes, and can greatly improve the added value of the oil slurry for producing high-value-added products such as needle coke, carbon black, carbon fiber, rubber filler, plastic plasticizer and heat conducting oil. However, a large amount of catalyst solid particles exist in the oil slurry, which seriously limits the high added value utilization of the oil slurry. For example, the oil slurry for producing carbon black or rubber filler requires that the solid content is not more than 500 ppm; the oil slurry for producing needle coke requires that the solid content is not more than 100 ppm, and the requirement for producing carbon fiber is more stringent, requiring that the solid content is less than 20 ppm. The content of solid catalyst powder in catalytic oil slurry is generally 2000-9000 ppm, and therefore, the removal of solid particles in the oil slurry is a prerequisite for high added value utilization of the oil slurry.

[0003] Due to the problems of large viscosity, poor flowability, difficulty in dispersion and easy solidification at room temperature of the oil slurry, it is difficult to realize solid-phase continuous separation of the oil slurry. Supercritical carbon dioxide has very low viscosity, close to the viscosity of gas and a large diffusion coefficient. After mixing supercritical carbon dioxide and oil slurry, the viscosity of the oil slurry will be greatly reduced, making it easy to separate the liquid and solid of the oil slurry. A mixer is needed when mixing the oil slurry and supercritical carbon dioxide. Chinese patent CN 211514352 U discloses a high-viscosity medium dynamic mixer, which can extrude the medium in the upper cavity to the inner cylinder in a spiral shape to mix with other media, so as to fully mix and uniformly mix the medium and solve the dead angle problem of the stirring device. However, since carbon dioxide can reach a supercritical state only when the pressure is higher than 7.38 MPa, the dynamic seal of the dynamic mixer is severely worn under high pressure, and it is difficult to realize long-period continuous operation. Chinese patent CN 211216214 U discloses a static mixer for high-viscosity liquid-phase materials, which effectively increases the mixing times of the liquid-phase materials by adding mixing nodes and flow guide nodes in the mixer. However, due to the poor flowability of the oil slurry, the flow is difficult and the pressure drop is large during mixing. SUMMARY

[0004] In order to solve the problems of flow difficulty, large pressure drop and difficult long-period continuous operation of the existing mixers when mixing the oil slurry and supercritical carbon dioxide, the application provides a supercritical carbon dioxide catalytic cracking oil slurry mixing system.

[0005] The application provides a supercritical carbon dioxide catalytic cracking oil slurry mixing system, which comprises a horizontal tank body and a supercritical carbon dioxide inlet, a dispersion plate, an oil slurry inlet, a settling cylinder, a mixture outlet, a partition, a supercritical carbon dioxide outlet and a light mixture outlet arranged from left to right along the horizontal tank body; the dispersion plate is in the shape of an ellipse as a whole and is arranged obliquely in the horizontal tank body, the periphery of the dispersion plate is sealingly connected with the inner wall of the horizontal tank body, and the dispersion plate is provided with injection holes; the supercritical carbon dioxide inlet and the oil slurry inlet are arranged on the left and right sides of the dispersion plate respectively, the supercritical carbon dioxide inlet is arranged on the left side head of the horizontal tank body, and the oil slurry inlet is arranged on the tank wall of the horizontal tank body on the right side of the dispersion plate and above the dispersion plate; the settling cylinder is arranged outside the bottom of the horizontal tank body on the right side of the dispersion plate, the mixture outlet is arranged at the bottom of the settling cylinder, the supercritical carbon dioxide outlet is arranged at the top of the horizontal tank body on the right side of the oil slurry inlet, the partition is arranged on the inner wall of the horizontal tank body on the right side of the settling cylinder, and the light mixture outlet is arranged on the outer wall of the horizontal tank body on the right side of the partition.

[0006] The application also provides another supercritical carbon dioxide catalytic cracking oil slurry mixing system, which comprises a horizontal tank body and a supercritical carbon dioxide inlet, an oil slurry inlet, a mixing element, a dispersion plate, a settling cylinder, a mixture outlet, a partition, a supercritical carbon dioxide outlet and a light mixture outlet arranged from left to right along the horizontal tank body; the dispersion plate is in the shape of an ellipse as a whole and is arranged obliquely in the horizontal tank body, the periphery of the dispersion plate is sealingly connected with the inner wall of the horizontal tank body, and the dispersion plate is provided with injection holes; the supercritical carbon dioxide inlet and the oil slurry inlet are arranged on the tank wall of the horizontal tank body on the left side of the dispersion plate, and the mixing element is arranged in the horizontal tank body on the left side of the dispersion plate; the settling cylinder is arranged outside the bottom of the horizontal tank body on the right side of the dispersion plate, the mixture outlet is arranged at the bottom of the settling cylinder, the supercritical carbon dioxide outlet is arranged at the top of the horizontal tank body on the right side, the partition is arranged on the inner wall of the horizontal tank body on the right side of the settling cylinder, and the light mixture outlet is arranged on the outer wall of the horizontal tank body on the right side of the partition.

[0007] The mixing element can be a multilayer wire mesh, a multilayer staggered grid or a support-filled material with an expanded specific surface area, so that the oil slurry is dispersed and mixed with the supercritical carbon dioxide through the large specific surface area, the stratification of the oil slurry and the supercritical carbon dioxide is avoided, and the mixture of the supercritical carbon dioxide and the oil slurry enters each injection hole.

[0008] The dispersion plate divides the horizontal tank body into two relatively independent spaces, and the injection holes on the dispersion plate are used for the supercritical carbon dioxide or the mixture of the supercritical carbon dioxide and the oil slurry to enter the space on the right side of the dispersion plate from the space on the left side of the dispersion plate. The injection holes can be round holes, slits or square holes, and from the perspective of easy manufacturing, the injection holes are preferably round holes with a diameter of 5-50 mm, and the slits have a width of 3-40 mm and a length of 5-50 mm.

[0009] As a further improvement, to achieve better mixing effect, a spray pipe with the same shape as the spray hole can be installed in the spray hole, and the right end of the spray pipe extends out of the plane of the dispersion plate. The left end of the spray pipe is open, and the right end can be open or closed. When the right end is closed, scattering holes are opened on the wall of the spray pipe on the right side of the dispersion plate for supercritical carbon dioxide or a mixture of supercritical carbon dioxide and oil slurry to pass through. At this time, the spray direction can be controlled by the position of the different scattering holes to form an interlaced spray, a multi-directional cutting mode to enhance the mixing effect. When the right end is open, the wall of the spray pipe on the right side of the dispersion plate can have scattering holes or not.

[0010] As an optional improvement, when the right end of the spray pipe is open, the diffusion effect can be enhanced by setting different dispersion components at the right end. The dispersion components can be a drainage plate, a flow expansion cone, or a rotating blade, etc. For example, an inclined drainage plate can be set at the right end of the spray pipe to control the direction of the supercritical carbon dioxide or the mixture of supercritical carbon dioxide and oil slurry. A flow expansion cone can also be installed at the right end of the spray pipe through a connecting plate. The flow expansion cone is conical in shape, and the bottom area is preferably larger than the area of the spray pipe, and the gap between the right end of the spray pipe and the flow expansion cone is preferably 0.2-2 times the diameter of the spray pipe. For another example, a set of rotating blades can be set at the right end of the spray pipe. The rotating blades are fixed to the right end of the spray pipe through a central shaft and a connecting plate, and the central shaft is coaxially arranged with the spray pipe. The rotating blades can be two or more pieces, and can rotate around the central shaft under the impact of the supercritical carbon dioxide or the mixture of supercritical carbon dioxide and oil slurry. In this way, on the one hand, the impact of the supercritical carbon dioxide or the mixture of supercritical carbon dioxide and oil slurry can be buffered, and on the other hand, the oil slurry near the rotating blades can be continuously stirred by the rotation of the rotating blades, thereby increasing the mixing range and intensity of the supercritical carbon dioxide and the oil slurry without the need for external power input.

[0011] As an optional arrangement, different dispersion components can be set at the right end of the spray pipe at different positions, and there is no need to uniformly set the same dispersion components. For example, the spray pipe near the bottom of the horizontal tank can have rotating blades at its right end, because the lower spray pipe is often immersed in the oil slurry, which can stir the oil slurry and achieve good mixing effect. The right end of the spray pipe near the top of the horizontal tank can be closed, and the high-speed medium is sprayed from the scattering holes on the wall of the spray pipe to improve the mixing effect.

[0012] The mixture of supercritical carbon dioxide and oil slurry on the right side of the dispersion plate enters the settling cylinder under the action of gravity to further settle, contact and mix. When the mixture flowing out of the outlet reaches the mixing requirement, it can exit the device. Since the flow in the horizontal tank is smooth, the mixture flowing out of the outlet may not meet the predetermined requirement, and the mixture can be returned to the oil slurry inlet again for mixing. Since the density of supercritical carbon dioxide is small and the density of oil slurry is large, the better the mixture is mixed, the lighter the density of the mixture is. Therefore, under the action of gravity, the mixed mixture will be stratified, and the fully mixed mixture will be light and will be stratified to the upper layer, so it will be in the upper layer of the liquid in the horizontal tank and will pass through the partition plate into the right side of the partition plate first. When the light mixture detected from the light mixture outlet on the right side of the partition plate meets the predetermined requirement, it can exit the device. When the predetermined requirement is not met, the light mixture can also be returned to the oil slurry inlet from the light mixture outlet for further mixing until the predetermined requirement is met.

[0013] The supercritical carbon dioxide not dissolved in the oil slurry in the horizontal tank will exit the tank from the supercritical carbon dioxide outlet at the top of the horizontal tank. It can be directly emptied or pressurized and returned to the supercritical carbon dioxide inlet through a pipeline for further dissolution in the oil slurry.

[0014] The present application has the following beneficial effects:

[0015] 1) The supercritical carbon dioxide and the oil slurry are mixed, and under the guiding action of the dispersion plate, the gravity of the oil slurry and the impact force of the supercritical carbon dioxide are fully utilized to increase the flowability of the oil slurry and improve the mixing effect, overcoming the shortcomings of large viscosity and poor flowability of the oil slurry, and achieving the effect of mixing and viscosity reduction;

[0016] 2) The impact force of supercritical carbon dioxide and different dispersion components are used to increase the contact strength of the oil slurry and supercritical carbon dioxide, and the entire flow is smooth and the flow pressure drop is small;

[0017] 3) The multi-stage mixing system and the backflow mode can be used to realize sufficient mixing of the oil slurry and the supercritical carbon dioxide, and ensure the mixing effect;

[0018] 4) There are no stirring elements and other components that require external power in the mixing system, which reduces the energy consumption of the system, can be suitable for high-pressure mixing conditions, and realizes long-period operation of the mixer. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structural schematic diagram of the mixing system of the present application;

[0020] Figure 2 is another structural schematic diagram of the mixing system of the present application;

[0021] Figure 3 is a structural schematic diagram of the dispersion plate;

[0022] Figure 4 is the structure diagram of the right end of the injection pipe when the dispersion component is a flow guide plate;

[0023] Figure 5 is the structure diagram of the right end of the injection pipe when the dispersion component is a flow expansion cone;

[0024] Figure 6 is the structure diagram of the right end of the injection pipe when the dispersion component is a rotating blade.

[0025] In the figure: 1-horizontal tank body, 2-oil slurry inlet, 3-dispersion plate, 4-injection pipe, 5-supercritical carbon dioxide inlet, 6-settling cylinder, 7-mixture outlet, 8-light mixture outlet, 9-baffle, 10-supercritical carbon dioxide outlet, 11-injection hole, 12-scattering hole, 13-flow guide plate, 14-connection plate, 15-flow expansion cone, 16-connection plate, 17-rotating blade, 18-center shaft, 19-mixing element. DETAILED DESCRIPTION

[0026] The application will be further described below in combination with the drawings.

[0027] Figure 1 is a supercritical carbon dioxide catalytic cracking oil slurry mixing system provided by the application.

[0028] As Figure 1 and Figure 3As shown, the supercritical carbon dioxide catalytic cracking slurry mixing system comprises a horizontal tank body 1, a supercritical carbon dioxide inlet 5, a dispersion plate 3, a slurry inlet 2, a settling cylinder 6, a mixture outlet 7, a partition 9, a supercritical carbon dioxide outlet 10 and a light mixture outlet 8 arranged from left to right along the horizontal tank body; the dispersion plate 3 is oval in shape and is arranged obliquely in the horizontal tank body 1, with its periphery sealingly connected to the inner wall of the horizontal tank body 1, and the dispersion plate 3 is provided with injection holes 11; the supercritical carbon dioxide inlet 5 and the slurry inlet 2 are arranged on the left and right sides of the dispersion plate 3, the supercritical carbon dioxide inlet 5 is arranged on the left side head of the horizontal tank body 1, and the slurry inlet 2 is arranged on the tank wall of the horizontal tank body 1 on the right side of the dispersion plate 3 and above the dispersion plate 3; the settling cylinder 6 is arranged on the outside of the bottom of the horizontal tank body 1 on the right side of the dispersion plate 3, the mixture outlet 7 is arranged at the bottom of the settling cylinder 6, the supercritical carbon dioxide outlet 10 is arranged at the top of the horizontal tank body 1 on the right side of the slurry inlet 2, the partition 9 is arranged on the inner wall of the horizontal tank body 1 on the right side of the settling cylinder 6, and the light mixture outlet 8 is arranged on the outer wall of the horizontal tank body 1 on the right side of the partition 9. The dispersion plate 3 divides the horizontal tank body 1 into two relatively independent spaces, and the injection holes 11 on the dispersion plate 3 allow supercritical carbon dioxide to enter the right space of the dispersion plate 3 from the left space of the dispersion plate 3. The injection holes 11 are circular holes for carbon dioxide entering the right space of the dispersion plate 3 from the supercritical carbon dioxide inlet 5. The slurry entering the tank body from the slurry inlet 2 first falls on the dispersion plate 3 and then moves to the right side of the tank body under the action of gravity and the impact force of supercritical carbon dioxide, and in the process of movement, the slurry continuously contacts with supercritical carbon dioxide, and supercritical carbon dioxide is dissolved into the slurry to achieve mixing effect. The injection holes 11 are provided with injection pipes 4 of the same shape as the injection holes, the right end of the injection pipe 4 extends out of the plane of the dispersion plate 3, and the injection pipe 4 is open at both ends.

[0029] Figure 2 The application provides another supercritical carbon dioxide catalytic cracking slurry mixing system.

[0030] As Figure 2 and Figure 3As shown, the supercritical carbon dioxide catalytic cracking slurry mixing system comprises a horizontal tank body 1, a supercritical carbon dioxide inlet 5, a slurry inlet 2, a mixing element 19, a dispersion plate 3, a settling cylinder 6, a mixture outlet 7, a partition 9, a supercritical carbon dioxide outlet 10 and a light mixture outlet 8 arranged from left to right along the horizontal tank body; the dispersion plate 3 is oval in shape and is obliquely arranged in the horizontal tank body 1, with its periphery being in sealing connection with the inner wall of the horizontal tank body 1, and the dispersion plate 3 is provided with injection holes 11; the supercritical carbon dioxide inlet 5 and the slurry inlet 2 are arranged on the tank wall of the horizontal tank body 1 at the left side of the dispersion plate 3, and the mixing element 19 is arranged in the horizontal tank body 1 at the left side of the dispersion plate 3; the settling cylinder 6 is arranged outside the bottom of the horizontal tank body at the right side of the dispersion plate 3, the mixture outlet 7 is arranged at the bottom of the settling cylinder 6, the supercritical carbon dioxide outlet 10 is arranged at the right side of the top of the horizontal tank body, the partition 9 is arranged on the inner wall of the horizontal tank body at the right side of the settling cylinder 6, and the light mixture outlet 8 is arranged on the outer wall of the horizontal tank body at the right side of the partition 9. The dispersion plate 3 divides the horizontal tank body 1 into two relatively independent spaces, and the injection holes 11 on the dispersion plate 3 are used for the mixture of supercritical carbon dioxide and slurry to flow from the left space of the dispersion plate 3 to the right space of the dispersion plate 3. The injection holes 11 are circular holes, and the same-shaped injection pipes 4 are arranged in the injection holes 11, with the right ends of the injection pipes 4 extending out of the plane of the dispersion plate 3, and the two ends of the injection pipes 4 being open.

[0031] For Figures 1-2 As shown, the two supercritical carbon dioxide catalytic cracking slurry mixing systems of the present application can enhance the mixing effect by arranging different dispersion components at the right end of the injection pipe, such as Figures 4-6 As shown:

[0032] Figure 4 In the dispersion component, the pipe wall of the injection pipe 4 is provided with scattering holes 12, and the right end of the injection pipe 4 is provided with a dispersion component flow guide plate 13, which is arranged obliquely relative to the axial direction of the injection pipe 4, and forms a certain resistance and flow guide effect on the supercritical carbon dioxide or the mixture of supercritical carbon dioxide and slurry sprayed from the injection pipe 4.

[0033] Figure 5 In the dispersion component, the right end of the injection pipe 4 is provided with a dispersion component flow expansion cone 15, which is fixed to the right end of the injection pipe 4 through a connecting plate 14, and the flow expansion cone 15 is conical in shape, with the bottom area being larger than the cross-sectional area of the injection pipe 4, and the gap between the right end of the injection pipe 4 and the flow expansion cone 15 being 0.2-2 times the diameter of the injection pipe.

[0034] Figure 6 In the dispersion component, the right end of the injection pipe 4 is provided with a rotating blade 17, which is fixed to the right end of the injection pipe 4 through a center shaft 18 and a connecting plate 16, and the center shaft 18 is coaxially arranged with the injection pipe 4, and the rotating blade 17 is two or more pieces, which can rotate around the center shaft 18 under the impact of the supercritical carbon dioxide or the mixture of supercritical carbon dioxide and slurry.

[0035] Figure 1 The working process of the mixing system shown is as follows:

[0036] The catalytic cracking slurry enters the horizontal tank body 1 through the slurry inlet 2 and falls on the dispersion plate 3; the supercritical carbon dioxide enters the horizontal tank body 1 through the supercritical carbon dioxide inlet 5 and is sprayed out through the spray pipe 4 on the dispersion plate 3 and then mixed with the slurry on the dispersion plate 3 in a top-down flow. The supercritical carbon dioxide and the slurry are mixed on the right side of the dispersion plate 3 and then enter the settling cylinder 6 under the action of gravity for further settling, contacting and mixing. When the mixture flowing out of the mixture outlet 7 meets the mixing requirements, it can leave the device. Since the supercritical carbon dioxide has a small density and the slurry has a large density, the better the mixture is mixed, the lighter the density of the mixture is. Therefore, under the action of gravity, the mixed mixture will be stratified, and the well-mixed mixture will be light and stratified to the upper layer, so it will be in the upper layer of the liquid inside the horizontal tank body 1 and will preferentially pass through the partition 9 into the right side of the partition, and then leave the device through the light mixture outlet 8 on the right side of the partition 9. The supercritical carbon dioxide that is not dissolved in the slurry leaves the tank body through the supercritical carbon dioxide outlet 10 located at the top of the horizontal tank body.

[0037] Figure 2 The working process of the mixing system shown is as follows:

[0038] The catalytic cracking slurry enters the horizontal tank body 1 through the slurry inlet 2 and is mixed with the supercritical carbon dioxide entering through the supercritical carbon dioxide inlet 5 under the action of the mixing element 19. The mixed slurry mixture is sprayed out through the spray pipe 4 on the dispersion plate 3 and then flows downward along the inclined dispersion plate 3 for further mixing. Under the action of gravity, the mixture first enters the settling cylinder 6 for further settling, contacting and mixing. When the mixture flowing out of the mixture outlet 7 meets the mixing requirements, it can leave the device. Since the supercritical carbon dioxide has a small density and the slurry has a large density, the better the mixture is mixed, the lighter the density of the mixture is. Therefore, under the action of gravity, the mixed mixture will be stratified, and the well-mixed mixture will be light and stratified to the upper layer, so it will be in the upper layer of the liquid inside the horizontal tank body 1 and will preferentially pass through the partition 9 into the right side of the partition, and then leave the device through the light mixture outlet 8 on the right side of the partition 9. The supercritical carbon dioxide that is not dissolved in the slurry leaves the tank body through the supercritical carbon dioxide outlet 10 located at the top of the horizontal tank body.

Claims

1. A supercritical carbon dioxide catalytic cracking slurry oil mixing system, characterized by: The device comprises a horizontal tank body and, from left to right along the horizontal tank body, a supercritical carbon dioxide inlet, a dispersion plate, an oil slurry inlet, a settling cylinder, a mixture outlet, a partition, a supercritical carbon dioxide outlet and a light mixture outlet.

2. A supercritical carbon dioxide catalytic cracking slurry oil mixing system, characterized by: The device comprises a horizontal tank body and, from left to right along the horizontal tank body, a supercritical carbon dioxide inlet, an oil slurry inlet, a mixing element, a dispersion plate, a settling cylinder, a mixture outlet, a partition, a supercritical carbon dioxide outlet and a light mixture outlet.

3. The mixing system of claim 1 or 2, characterized in that: A jet pipe with the same shape as the jet hole is installed in the jet hole, the right end of the jet pipe extends out of the plane of the dispersion plate, and the right end of the jet pipe is open.

4. The mixing system of claim 3, wherein: The jet pipe wall on the right side of the dispersion plate is provided with a scattering hole.

5. The mixing system of claim 1 or 2, wherein: A jet pipe with the same shape as the jet hole is installed in the jet hole, the right end of the jet pipe extends out of the plane of the dispersion plate, and the right end of the jet pipe is open.

6. The mixing system of claim 3, wherein: The right end of the jet pipe is provided with a flow guide plate, which is axially inclined relative to the jet pipe, and forms a certain blocking and guiding effect on the supercritical carbon dioxide or the mixture of supercritical carbon dioxide and oil slurry sprayed by the jet pipe.

7. The mixing system of claim 3, wherein: The right end of the jet pipe is provided with a flow expansion cone, which is fixed to the right end of the jet pipe through a connecting plate, and the flow expansion cone is conical.

8. The mixing system of claim 3, wherein: The right end of the jet pipe is provided with a rotating blade, which is fixed to the right end of the jet pipe through a center shaft and a connecting plate, the center shaft is coaxially arranged with the jet pipe, and the rotating blade is two or more pieces.

9. The mixing system of claim 4, wherein: The right end of the jet pipe is provided with a flow guide plate, which is axially inclined relative to the jet pipe, and forms a certain blocking and guiding effect on the supercritical carbon dioxide or the mixture of supercritical carbon dioxide and oil slurry sprayed by the jet pipe.

10. The mixing system of claim 4, wherein: The right end of the jet pipe is provided with a flow expansion cone, which is fixed to the right end of the jet pipe through a connecting plate, and the flow expansion cone is conical.

11. The mixing system of claim 4, wherein: The right end of the injection pipe is provided with rotating blades, the rotating blades are fixed to the right end of the injection pipe through a central shaft and a connecting plate, the central shaft is coaxially arranged with the injection pipe, and the rotating blades are two or more.

12. The mixing system of claim 2, wherein: The mixing element is a multi-layer wire mesh, or a multi-layer staggered grid, or a support-equipped expanded specific surface area filler.

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