Venturi separator and use thereof

Abstract

This invention relates to a Venturi separator, characterized in that the Venturi separator comprises a Venturi tube and a liquid phase collection tube surrounding at least a portion of the structure of the Venturi tube. The Venturi tube includes the following sections connected in sequence: optionally a constant diameter section, a narrowing section, a throat, and an expanding section. The Venturi separator has a gas phase inlet, a liquid phase inlet, a liquid phase outlet, and a gas phase outlet. An opening is provided on the sidewall of the expanding section of the Venturi tube or at the end of the expanding section, leading to the liquid phase collection tube, so that the liquid phase leaves the Venturi tube under centrifugal force and enters the liquid phase collection tube. This invention also relates to the use of this Venturi separator in chemical processes.

Description

Technical Field

[0001] This invention relates to the field of chemical separation, particularly to the field of petrochemical aromatic hydrocarbon separation, and specifically to a Venturi separator and its applications. Background Technology

[0002] Chemical separation technology is a crucial aspect of chemical engineering. It's indispensable in various fields, including petroleum refining, plastics and fibers, hydrometallurgy, isotope separation, biopharmaceutical refining, nanomaterial preparation, flue gas desulfurization, and fertilizer and pesticide production. Most raw materials and products in chemical production are mixtures, requiring the use of differences in the properties of the components or separating agents to separate and purify them. Common separation methods in chemical production can be broadly categorized into mechanical separation and mass transfer separation. Mechanical separation methods simply separate the phases; simple mechanical methods can separate two phases without any mass transfer. Examples include filtration, sedimentation, centrifugation, cyclone separation, and electrostatic precipitators. Mass transfer separation methods, on the other hand, are used to separate various homogeneous mixtures, characterized by the occurrence of mass transfer.

[0003] In the prior art, separation devices utilizing the Venturi principle, such as wet Venturi scrubbers, have been disclosed. Wet scrubbers utilize negative pressure in the gas phase to create a uniform water film in the liquid phase. The gas stream carrying dust enters the Venturi separator tangentially, passing through a Venturi throat equipped with a washing liquid spray. The gas stream is rapidly accelerated at the Venturi throat, resulting in thorough mixing of the relative motion between the gas stream and the liquid, causing dust or pollutants to accumulate with the liquid droplets.

[0004] CN104226074A discloses an acid-containing tail gas scrubbing device, which includes a condenser, a venturi tube, and a phase separator. The upper port of the venturi tube is the air inlet, and the lower port is the discharge outlet. The air inlet of the venturi tube is connected to the air outlet of the condenser. A water inlet pipe is tangentially connected to the upper part of the venturi tube so that the scrubbing water enters the upper part of the venturi tangentially. However, this acid-containing tail gas scrubbing device has a complex structure, consists of multiple devices, and occupies a large area.

[0005] CN108525443A discloses a Venturi decontamination device for gas-liquid processing, which includes an air inlet pipe, a liquid inlet, a Venturi constriction tube, and a Venturi expansion tube. The two ends of the Venturi constriction tube are connected to the air inlet pipe and the Venturi expansion tube, respectively. The liquid inlet is located at the connection between the Venturi constriction tube and the Venturi expansion tube.

[0006] CN206577612U discloses a Venturi mixer with a spiral guide plate in the throat, which can use the spiral guide plate in the throat to force the mainstream fluid entering the throat to rotate and flow, thereby introducing the fluid more uniformly and mixing it better with the mainstream fluid after introduction.

[0007] However, existing separation systems using venturi tubes typically require one or more other devices, such as phase separators, to be used in series. This results in low equipment integration, a large footprint, and high investment costs.

[0008] Therefore, the purpose of this invention is to provide a Venturi separator suitable for chemical production processes, which overcomes the shortcomings of such equipment in the prior art and has the advantages of high structural integration, small footprint, low investment cost, and high separation efficiency. Summary of the Invention

[0009] Through in-depth research, the inventors have surprisingly discovered that in multiphase separation methods in chemical processes, combining a Venturi tube with the helical flow of fluids can simultaneously achieve mass transfer and mechanical separation between fluids. This allows for rapid and efficient mixing and separation of multiphase fluids. Furthermore, by creatively placing the Venturi tube within the liquid phase collection pipe and strategically positioning the fluid entry point, the helical flow characteristics within the Venturi tube can be fully utilized to achieve continuous and enhanced mixing and separation of multiphase fluids, thus efficiently realizing mass transfer and separation. In addition, the ingenious combination of the Venturi tube and the liquid phase collection pipe results in a simple and compact structure for the Venturi separator, eliminating the need for subsequent equipment (such as phase separators), saving space, and requiring a small footprint. This makes it suitable for integration with various other chemical equipment, such as distillation columns, and reduces investment costs. Moreover, the inventors have found that using a vortex core tube in the Venturi separator of this invention can rapidly achieve high-speed helical flow of gas within the Venturi tube.

[0010] To achieve the above objectives, according to a first aspect of the present invention, a Venturi separator is provided, characterized in that the Venturi separator includes a Venturi tube and a liquid phase collection tube surrounding at least a portion of the structure of the Venturi tube, the Venturi tube including the following sections connected in sequence: optionally a constant diameter section, a narrowing section, a throat, and an expanding section, the Venturi separator having a gas phase inlet, a liquid phase inlet, a liquid phase outlet, and a gas phase outlet, wherein an opening leading to the liquid phase collection tube is provided on the side wall of the expanding section of the Venturi tube or at the end of the expanding section, so that the liquid phase leaves the Venturi tube and enters the liquid phase collection tube under the action of centrifugal force.

[0011] According to a second aspect of the invention, the invention also relates to the use of the Venturi separator described in the first aspect for multiphase separation in chemical processes, particularly for gas-liquid separation integrated into organic compounds.

[0012] The Venturi separator according to the present invention has the following advantages: its structure is ingeniously designed, the arrangement of each component is reasonable and compact, it can operate continuously, has high separation efficiency, occupies a small area, saves space, has low investment cost, and can be used in conjunction with other devices such as distillation towers in chemical production. Attached Figure Description

[0013] The accompanying drawings are used to illustrate the technical solutions of the present invention and form part of the specification, but do not constitute a limitation on the present invention. Wherein:

[0014] Figure 1 A schematic diagram of the aromatic hydrocarbon extraction system involved in Embodiment 1 of the present invention is shown.

[0015] Figure 2 A schematic diagram of the structure of a Venturi separator according to an embodiment of the present invention used in Example 1 is shown.

[0016] Explanation of reference numerals in the attached figures

[0017] Figure 1 In the column, 101: Aromatic hydrocarbon extraction distillation column; 102: Venturi separator; 103: reflux tank; 104: condenser; 1: Aromatic hydrocarbon feed inlet; 2: Extraction solvent inlet; 3: Top gas phase outlet; 4: Washed gas outlet; 5: Reflux tank inlet; 6: Washing liquid inlet; 7: Residual oil product outlet; 8: Washing liquid outlet; 9: Bottom liquid outlet; 10: Side stream inlet; 11: Top gas phase inlet; 12: Aqueous phase outlet.

[0018] Figure 2 In the middle, 13: vortex core tube; 14: venturi tube; 15: washing liquid inlet pipe; 16: liquid phase collection pipe; 17: top opening of the expansion section; 18: open pipe. Detailed Implementation

[0019] The specific embodiments of this application are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustrating and explaining the technical solutions of the present invention, and are not intended to limit the present invention.

[0020] Any specific numerical value (including the endpoints of a range) disclosed in this specification is not limited to its exact value, but should be understood to also include values ​​close to that exact value, such as all possible values ​​within ±5% of that exact value. Furthermore, with respect to the disclosed numerical range, one or more new numerical ranges can be obtained by arbitrarily combining the endpoint values ​​of the range, the endpoint values ​​with specific point values ​​within the range, and the specific point values ​​themselves; these new numerical ranges should also be considered as specifically disclosed in this specification.

[0021] Unless otherwise stated, the terms used in this specification have the same meaning as commonly understood by those skilled in the art. If a term is defined in this specification and its definition differs from the common understanding in the art, the definition herein shall prevail.

[0022] In this application, except where expressly stated, any matters or issues not mentioned are directly applicable to those known in the art without any modification. Furthermore, any embodiment described herein can be freely combined with one or more other embodiments described herein, and the resulting technical solutions or ideas shall be considered part of the original disclosure or original record of this invention, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider the combination to be clearly unreasonable.

[0023] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its synonyms such as "including" or "containing" shall be understood to include the stated elements or components without excluding other elements or other components.

[0024] In the specification of this invention, it should be understood that the directional terms such as "length", "angle", "above", "below", "vertical", "standing", "horizontal", "top", "bottom", "inner", "outer", and "tangential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0025] In this specification, unless otherwise explicitly stated and limited, the terms "set up," "connected," "linked," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0026] According to a first aspect of the present invention, a Venturi separator is provided, characterized in that the Venturi separator includes a Venturi tube and a liquid phase collection tube surrounding at least a portion of the structure of the Venturi tube, the Venturi tube including the following sections connected in sequence: an expanding section, a throat, a narrowing section, and optionally a constant diameter section, the Venturi separator having a gas phase inlet, a liquid phase inlet, a liquid phase outlet, and a gas phase outlet, wherein an opening is provided on the side wall of the expanding section of the Venturi tube or at the end of the expanding section and leads to the liquid phase collection tube, so that the liquid phase leaves the Venturi tube under centrifugal force and enters the liquid phase collection tube.

[0027] According to one embodiment of the first aspect described above, the Venturi separator is placed vertically, and its gas phase inlet and liquid phase inlet are optionally connected to other devices for continuous processing of gases and liquids from other devices, and its liquid phase outlet and gas phase outlet are also optionally connected to other devices for subsequent processing or storage.

[0028] According to one embodiment of the first aspect described above, the Venturi tube optionally includes a constant diameter section, which (if present) is connected to a reduced diameter section and can be used to connect to other equipment or to install auxiliary equipment, such as eddy current core tubes; the throat is the connection between the reduced diameter section and the expanded diameter section, having the smallest diameter in the Venturi tube, and can also be a section of constant diameter pipe connecting the reduced diameter section and the expanded diameter section, with an opening for gas and liquid to exit the Venturi tube provided in or at the top of the expanded diameter section, and optionally the constant diameter section, the reduced diameter section, the throat, and the expanded diameter section are connected from bottom to top.

[0029] According to one embodiment of the first aspect described above, a liquid phase injection port is provided on the wall of the constricted section of the Venturi tube. That is, the liquid phase input from the liquid phase inlet of the Venturi separator is injected into the constricted section of the Venturi tube to contact and mix with the spirally flowing gas within the tube. Because the gas flows at high speed in a spiral manner within the constricted section of the Venturi tube, the angular velocity of the spiral flow increases as the diameter of the constricted section decreases. Therefore, when the liquid phase is injected into the Venturi tube in the constricted section, it flows and mixes with the spirally flowing gas, resulting in increasingly intense liquid turbulence and more thorough gas-liquid mixing. Consequently, the mass transfer between the gas and liquid is more efficient, and the separation effect is better. The liquid phase injection port on the wall of the Venturi tube can be located at any position within the constricted section. Preferably, the distance between the location of the liquid phase injection port and the throat is 1 / 10 to 2 / 3 of the length of the constricted section; more preferably, the distance is 1 / 8 to 1 / 2 of the length of the constricted section.

[0030] According to one embodiment of the first aspect described above, a nozzle can be provided at the liquid phase injection port on the wall of the venturi tube to spray the liquid phase into the gas in the venturi tube in the form of small droplets, thereby accelerating gas-liquid mixing. The injection flow rate and velocity of the liquid phase can be adjusted by those skilled in the art according to actual needs and gas flow rate and velocity. The injection direction of the nozzle can be any direction, preferably at an angle of less than 90° to the gas flow direction at the location of the liquid phase injection port, more preferably less than 60°, more preferably less than 30°, for example less than 15°, and more preferably in the same direction as the gas flow direction.

[0031] According to one embodiment of the first aspect described above, the liquid collection tube surrounds at least a portion of the structure of the Venturi tube around its outer periphery, for example, at least surrounding the sidewall of the enlarged section of the Venturi tube or an opening provided at the end of the enlarged section. The liquid collection tube extends downward, potentially surrounding the enlarged section of the Venturi, or even the throat and narrowed section, or even the entire Venturi tube. Preferably, the Venturi separator of the present invention includes a liquid collection tube and a Venturi tube disposed within the liquid collection tube. If the liquid phase collection tube surrounds the entire Venturi tube, then the liquid delivery pipe for transporting the liquid phase, which is connected to the liquid phase inlet on the wall of the Venturi tube, needs to pass through the wall of the liquid phase collection tube. In this case, the liquid phase inlet of the Venturi separator is connected to the liquid phase inlet on the wall of the Venturi tube via the delivery pipe that passes through the wall of the liquid phase collection tube. The angle between the delivery pipe and the generatrix of the conical section of the Venturi tube below the delivery pipe can be 10-90°, preferably 30-80°, for example 40°, 50°, 60° or 70°.

[0032] According to one embodiment of the first aspect above, the top of the liquid phase collection tube is closed, but an open tube is provided for the gas phase discharge of the Venturi separator, the upper outlet of the open tube forms the gas phase outlet of the Venturi separator, and the open tube passes downward through the top of the liquid phase collection tube and extends to the end of the enlarged section of the Venturi tube. If an opening for liquid phase exiting the Venturi tube is provided on the side wall of the expanded section, then the opening pipe is connected to the end of the expanded section of the Venturi tube, and optionally a liquid phase outlet is also provided between the lower end of the opening pipe and the end of the expanded section of the Venturi tube to allow liquid that was not discharged from the outlet in the expanded section to be discharged here. If the opening for liquid phase exiting the Venturi tube is located at the end of the expanded section of the Venturi tube, then the lower end of the opening pipe and the end of the expanded section of the Venturi tube are completely or partially spaced to form an opening for liquid exiting the Venturi tube. Therefore, the opening is a continuous or intermittent annular opening, and the height of the opening can be adjusted by raising or lowering the opening pipe. The height of the opening can be varied within a certain range according to the liquid phase flow rate, as long as it satisfies the requirement that almost all the liquid phase leaves the Venturi tube and enters the liquid phase collection tube under the action of centrifugal force, and can prevent a significant amount of gas from entering the liquid phase collection tube. For example, the height of the opening is less than 10 cm, for example less than 5 cm.

[0033] According to one embodiment of the first aspect above, the diameter of the open pipe can be slightly larger than the diameter of the end opening of the expansion section. For example, the diameter of the open pipe is less than 5% larger than the diameter of the end opening of the expansion section. Preferably, the diameter of the open pipe is the same as the diameter of the end opening of the expansion section.

[0034] According to one embodiment of the first aspect described above, the Venturi separator further includes a device for causing gas to enter the Venturi tube in a helical flow manner or for causing gas to enter the Venturi tube tangentially, so that the gas flows upward in a helical manner within the Venturi tube. The device is disposed at the inlet of the reduced-diameter section of the Venturi tube or in the equal-diameter section of the Venturi tube. The device for causing the gas to flow helically within the Venturi tube can be a device commonly used in the art, such as a vortex core tube.

[0035] According to one embodiment of the first aspect above, the device for causing gas to flow in a spiral manner in a Venturi tube is a vortex core tube, the inside of which is provided with a spiral guide vane, the vortex core tube is disposed at the inlet of the reduced diameter section of the Venturi tube or in the equal diameter section of the Venturi tube, and the bottom inlet of the vortex core tube is formed as the gas phase inlet of the Venturi separator.

[0036] According to one embodiment of the first aspect described above, the number of vortex core tubes can be selected according to actual needs (such as gas flow rate), and there can be one or more. If multiple vortex core tubes are used, they can be arranged in parallel.

[0037] According to one embodiment of the first aspect described above, the diameter of the liquid phase collection tube is larger than the maximum diameter of the venturi tube disposed therein, and those skilled in the art can select the appropriate diameter based on actual needs and site conditions. Preferably, the diameter of the liquid phase collection tube is 30% larger than the maximum diameter of the venturi tube disposed therein, more preferably 20%, for example, 10% or 5%.

[0038] According to one embodiment of the first aspect described above, a structure guiding the spiral flow of gas is provided on the inner wall of any selected constant-diameter section, narrow-diameter section, throat, and wide-diameter section of the Venturi tube. This allows the gas flow or gas-liquid flow to spirally ascend or descend along the inner wall of the Venturi tube. The structure can be selected from swirl vanes or spiral guide vanes, which can increase the tangential velocity of the fluid, avoid the fluid adhering to the wall effect, enhance the contact between the gas and liquid, and further improve the separation efficiency of the Venturi separator. The helix angle φ of the swirl vanes or spiral guide vanes can be selected by those skilled in the art according to actual conditions and adjusted according to changes in the diameter of the Venturi tube.

[0039] According to a preferred embodiment, the swirl vane or helical guide vane can be a single or multi-head swirl vane or a single or multi-head helical guide vane with n threads (n is a positive integer greater than or equal to 1). If the swirl vane or helical guide vane is multi-headed, and the pitch of the multi-head swirl vane or multi-head helical guide vane (n>1) is the same as the pitch of the single-head swirl vane or single-head helical guide vane (n=1), since the helix angle φ of the multi-head helical guide vane is approximately n times that of the single-head helical guide vane, the multi-head helical guide vane can better guide the fluid on the inner wall of the Venturi tube, and can significantly reduce the pressure loss of the Venturi separator.

[0040] According to one embodiment of the first aspect above, in the Venturi separator, the volumetric flow rate ratio of the gas phase to the liquid phase can vary within a wide range, for example, 70-2500:1, preferably 200-1100:1; the inlet gas velocity of the Venturi separator is 1 m / s to 40 m / s, preferably 5 m / s to 35 m / s; the pressure loss of the Venturi separator is below 20 kPa, for example, 0.1 kPa to 10 kPa, preferably 0.2 kPa to 5 kPa; the absolute pressure of the liquid phase at the liquid phase inlet is above 170 kPa, preferably 180 kPa to 1500 kPa, preferably 200 to 1000 kPa, more preferably 250 to 700 kPa.

[0041] According to one embodiment of the first aspect above, in the Venturi separator, the bottom of the liquid phase collection tube is connected to the liquid phase outlet of the Venturi separator through a liquid discharge pipe, wherein a liquid seal is provided at the bottom of the liquid phase collection tube to prevent gas from entering the liquid discharge pipe.

[0042] According to a second aspect of the invention, the invention also relates to the use of the Venturi separator for liquid-gas separation or liquid-gas purification.

[0043] According to one embodiment of the second aspect above, the Venturi separator is used for stripping separation of liquid components in the liquid phase or for washing or extraction separation of gas components in the gas phase, for example, using a washing liquid to elute solvent contained in the gas from the top of a distillation column.

[0044] The liquid phase removal rate obtained by using the Venturi separator according to the present invention can reach more than 82%, preferably 90% to 99.9%, and the liquid phase separation accuracy is 1 μm to 10 μm, wherein the above-mentioned liquid phase removal rate = weight of liquid phase entering the liquid phase collection tube / total weight of liquid phase injected into the Venturi tube.

[0045] The following examples further illustrate the beneficial effects of the technical solution of the present invention, but are by no means intended to limit the scope of the present invention.

[0046] In these embodiments, the Venturi separator of the present invention is integrated into an aromatic extraction system to separate the extraction solvent entrained in the overhead gas of an aromatic extraction distillation column.

[0047] The aromatic feedstock used in the aromatic extraction systems involved in the examples and comparative examples is the C6-C7 fraction of reformed oil, and the aromatic mass fraction in the aromatic feedstock is 65%.

[0048] The sulfolane used was a chemical reagent purchased from Innovent Biologics Inc. Unless otherwise specified, all other reagents were obtained commercially.

[0049] Example 1

[0050] In this embodiment, the following is used: Figure 1 The aromatic hydrocarbon extraction system shown and such Figure 2 The Venturi separator shown in the figure includes an aromatics extraction distillation column 101, a Venturi separator 102, a reflux tank 103, and a condenser 104.

[0051] The aromatic extraction distillation column 101 includes an aromatic feedstock inlet 1, an extraction solvent inlet 2, a side stream inlet 10, a bottom liquid outlet 9, and a top gas outlet 3; the Venturi separator 102 includes a gas inlet 11, a liquid inlet (washing water in this embodiment) 6, a washing liquid outlet (washing water in this embodiment) 8, and a gas outlet (washed gas in this embodiment) 4; the reflux tank 103 includes a reflux tank inlet 5, an aqueous outlet 12, and an oil outlet 7.

[0052] The top gas phase outlet 3 of the aromatic extraction distillation column 101 is connected to the gas phase inlet 11 of the Venturi separator 102; the washing liquid (washing water in this embodiment) outlet 8 of the Venturi separator 102 is connected to the side inlet 10 of the aromatic extraction distillation column 101; the gas phase (washed gas) outlet 4 of the Venturi separator 102 is connected to the inlet 5 of the reflux tank 103; the aqueous phase outlet 12 of the reflux tank 103 is connected to the liquid phase (washing water in this embodiment) inlet 6 of the Venturi separator 102; the oil phase outlet 7 of the reflux tank 103 forms the system's residual oil product outlet; the condenser 104 is disposed between the gas phase (washed gas) outlet 4 of the Venturi separator 102 and the inlet 5 of the reflux tank.

[0053] The Venturi separator 102 includes a vertically arranged liquid phase collection pipe 16 and a Venturi tube 14 vertically arranged inside the liquid phase collection pipe 16. A liquid phase inlet (also referred to as a washing liquid inlet in this embodiment) is provided in the upper 1 / 3 of the narrowed section near the throat of the Venturi tube 14. The Venturi separator includes the Venturi tube 14, a vortex core tube 13, a washing liquid inlet pipe 15, and the liquid phase collection pipe 16. The washed gas outlet 4 of the Venturi separator 102 is located at the top of the liquid phase collection pipe 16. The liquid phase inlet 6 of the Venturi separator 102 is connected to the washing liquid inlet below the throat of the Venturi tube 14 through the washing liquid inlet pipe 15. The bottom inlet of the Venturi tube is formed as the gas phase inlet of the Venturi separator or is connected to the gas phase inlet of the Venturi separator. The washed gas outlet of the Venturi separator is connected to the top outlet of the Venturi tube through an open pipe 18. The Venturi tube 14 includes, from bottom to top, a series of components. The secondary interconnected sections include a constant diameter section, a reduced diameter section, a throat, and an expanded diameter section. The washing liquid inlet pipe 15 passes through the wall of the liquid phase collection pipe 16 and connects to the washing liquid inlet on the reduced diameter section of the Venturi tube 14, and is close to the throat of the Venturi tube. The top of the liquid phase collection pipe 16 is provided with an open pipe 18, the top opening of which can also serve as the post-wash gas outlet 4 of the Venturi separator 102. The bottom opening of the open pipe 18 extends downward through the top of the liquid phase collection pipe and extends to... An opening 17 is formed inside the liquid collection pipe 16 and is spaced apart from the top end of the expanded section of the Venturi tube 14; the diameter of the opening pipe 18 is the same as the diameter of the top opening of the expanded section; the angle between the washing liquid inlet pipe 15 and the axis of the Venturi tube 14 is 90°; the vortex core tube 13 is set in the equal diameter section of the Venturi tube, and the bottom inlet of the vortex core tube 13 can also be used as the gas phase inlet 11 of the Venturi separator 102; there is one vortex core tube.

[0054] Aromatic feedstock enters aromatic extraction distillation column 101 through aromatic feedstock inlet 1, and solvent sulfolane enters aromatic extraction distillation column 101 through extraction solvent inlet 2. Aromatic feedstock and sulfolane are in contact in aromatic extraction distillation column 101 for aromatic extraction. The gas at the top of aromatic extraction distillation column 101 is discharged from the top gas phase outlet 3, and after passing through the vortex core tube 13 of Venturi separator 102, it forms an upward vortex flow of gas and enters Venturi tube 14. Aqueous phase from reflux tank 103 is sprayed into Venturi tube 14 through washing liquid inlet pipe 15. The vortex flow of gas contacts the washing liquid for water washing and removal treatment. The gas and washing liquid flow together along the wall of Venturi tube. The upward spiral flow continues, resulting in washed gas and solvent-containing washing liquid. In the expansion section, under the influence of centrifugal force, the solvent-containing washing liquid gradually accumulates on the outside of the vortex. This solvent-containing washing liquid, under centrifugal force, is discharged from the opening between the bottom of the open pipe 18 and the top of the expansion section, entering the liquid collection pipe 16. Under gravity, it reaches the washing liquid outlet 8 at the bottom of the Venturi separator and is discharged. The washed gas exits from the washed gas outlet 4, passes through the condenser 104, and enters the reflux tank 103 for processing. Residual oil is discharged from the oil phase outlet 7 of the reflux tank 103. The liquid phase discharged from the washing liquid outlet 8 is returned to the aromatics extraction distillation tower 101 for recycling. The liquid phase removal rate at the top gas outlet of the Venturi separator 102 is 99.8%. The specific operating conditions of the aromatics extraction system are shown in Table 1.

[0055] Example 2

[0056] The method is the same as in Example 1, except that the Venturi tube in this example does not include a vortex core tube, but instead uses tangential gas inlet relative to the inner wall of the Venturi tube inlet, with an inlet gas velocity of 40 m / s. The liquid phase removal rate at the gas phase outlet at the top of the Venturi separator 102 is 83%, and the specific operating conditions of the aromatic hydrocarbon extraction system are shown in Table 1.

[0057] Example 3

[0058] The method is the same as in Example 1, except that the volume flow ratio of gas phase to washing liquid is 1200:1 in this example; the liquid phase removal rate at the gas phase outlet of the Venturi separator 102 is 99.8%; and the specific operating conditions of the aromatic hydrocarbon extraction system are shown in Table 1.

[0059] Example 4

[0060] The method is the same as in Example 1, except that the inlet gas velocity at the venturi tube inlet is 40 m / s and the absolute pressure at the liquid phase injection port is 180 kPa; the liquid phase removal rate at the gas phase outlet at the top of the venturi separator 102 is 95%, and the specific operating conditions of the aromatic hydrocarbon extraction system are shown in Table 1.

[0061] Example 5

[0062] The method is the same as in Example 1, except that in this example, the distance between the liquid injection port and the throat of the Venturi tube is 2 / 3 of the diameter reduction section length, the absolute pressure of the washing liquid at the liquid injection port is 500 kPa, the liquid removal rate at the gas outlet at the top of the Venturi separator 102 is 99.8%, and the specific operating conditions of the aromatic extraction system are shown in Table 1.

[0063] Example 6

[0064] The method is the same as in Example 1, except that in this example, the liquid phase injection port is set at the throat of the Venturi tube, the volume flow ratio of the gas phase to the washing liquid is 1200, the absolute pressure of the washing liquid at the liquid phase injection port is 250 kPa, the liquid phase removal rate at the gas phase outlet at the top of the Venturi separator 102 is 95%, and the specific operating conditions of the aromatic hydrocarbon extraction system are shown in Table 1.

[0065] Table 1

[0066]

[0067] Comparative Example 1

[0068] use Figure 1 The process shown is conventional, but a non-aromatic distillation column (NA column) is used instead of a venturi separator. That is, an extraction distillation column (ED column) and a non-aromatic distillation column (NA column) are connected in series to recover trace amounts of solvent from the top gas of the ED column. The raw materials, solvents and solvent ratios used are the same as in Example 1. The operating conditions of this Comparative Example 1 are shown in Table 2.

[0069] Table 2

[0070]

[0071] Comparative Example 2

[0072] use Figure 1 The process shown is the same as in Example 1, but a non-aromatic distillation section is used instead of a venturi separator. Specifically, a non-aromatic distillation section is set in the upper section of the extraction distillation column (ED column) to recover trace amounts of solvent in the raffinate. The feedstock, solvent, and solvent ratio are the same as in Example 1, and the operating conditions are shown in Table 3.

[0073] Table 3

[0074]

[0075] Test Example 1

[0076] The raffinate products obtained in Examples 1-4 and Comparative Examples 1-2 were analyzed for their composition. The composition of the raffinate was determined by the standard methods of ASTM D-6536 and GGBM-04-2005, which were used to analyze the aromatic content and solvent content. The product composition is shown in Table 4.

[0077] Table 4

[0078] Non-aromatic hydrocarbon mass fraction / % Aromatics mass fraction / % Solvent mass concentration (μg / g) Example 1 99.95 0.05 1 Example 2 99.95 0.05 7 Example 3 99.95 0.05 5 Example 4 99.95 0.05 3 Example 5 99.95 0.05 1 Example 6 99.95 0.05 20 Comparative Example 1 99.90 0.10 1 Comparative Example 2 99.47 0.53 3

[0079] As shown in Table 4, the aromatic extraction system incorporating the Venturi separator according to the present invention significantly increases the content of non-aromatic hydrocarbons in the raffinate and significantly reduces the content of aromatic hydrocarbons in the raffinate, further improving the quality and yield of aromatic products in the extract. This demonstrates that the Venturi separator according to the present invention can be combined with an aromatic extraction distillation column, enabling the column to efficiently separate aromatic hydrocarbons and other organic compounds in the gas phase. Furthermore, the Venturi separator according to the present invention has a small footprint, requires no additional heating, and further reduces energy consumption.

[0080] A comparison of Example 1 and Comparative Example 1 shows that the solvent (sulfolane) content in the raffinate product obtained by the aromatic extraction system using the Venturi separator of the present invention can reach a level comparable to that of Comparative Example 1. However, the addition of the aqueous phase from the Venturi separator in the aromatic extraction distillation column of the present invention improves the solvent selectivity, resulting in a lower aromatic content in the raffinate. Furthermore, the absence of a reboiler at the bottom of the NA column and reflux at the top of the column saves energy.

[0081] By comparing Example 1 and Comparative Example 2, it can be seen that the system of the present invention avoids the reflux of non-aromatic raffinate oil into the aromatic extraction distillation tower, increases the content of non-aromatics in the raffinate oil, reduces the content of aromatics in the raffinate oil, and further improves the yield of aromatics in the extract; at the same time, it improves the solvent removal effect in the raffinate oil.

[0082] A comparison of Examples 1 and 2 shows that, when the Venturi separator of the present invention uses a vortex core tube, the liquid phase removal rate is higher and the solvent residue content in the raffinate product is significantly lower compared with the tangential air intake method.

[0083] A comparison of Examples 1 and 3 shows that, within the preferred range of the present invention for the volumetric flow rate ratio of the top gas phase / washing liquid, the solvent content in the raffinate product is lower.

[0084] A comparison of Examples 1 and 4 shows that, within the range of the inlet gas velocity of the Venturi tube and the absolute pressure at the liquid phase injection port of the present invention, the liquid phase removal rate is significantly higher and the solvent residue content in the raffinate product is lower.

[0085] A comparison of Examples 1 and 5 shows that, within the range of the inlet gas velocity of the Venturi tube and the absolute pressure at the liquid injection port of the present invention, when the distance from the liquid injection port to the throat is 2 / 3 of the narrowed section length, the pressure drop generated by the injection of the liquid phase is significantly higher than that generated when the distance from the liquid injection port to the throat is 1 / 3 of the narrowed section length. A higher pressure is required at the top of the extraction distillation column to maintain the same gas velocity. However, the separation effect of the two is comparable, indicating that when the washing liquid is injected at a position within the preferred range of the present invention, the extraction distillation column can maintain optimal operating conditions.

[0086] A comparison of Examples 1 and 6 shows that, within the range of the inlet gas velocity of the Venturi tube and the absolute pressure at the liquid injection port of the present invention, the separation effect produced by the liquid phase being injected in the constriction section is much higher than that produced by the liquid phase being injected in the throat. This is because when the liquid phase is injected at the throat, it does not experience the constriction section, resulting in insufficient gas-liquid mixing. Furthermore, the larger volumetric flow rate ratio between the gas phase and the washing liquid means that less solvent in the gas is washed by the liquid phase, thus resulting in a higher solvent residue content in the raffinate oil product.

[0087] A comparison of Examples 1 and 6 shows that, under the range of the gas velocity at the venturi inlet and the absolute pressure at the liquid injection port of the present invention, because the liquid phase is injected at a lower position in the constriction section, less liquid phase can be injected when processing gas at the same velocity, resulting in lower gas processing efficiency and higher solvent residue content in the raffinate product.

[0088] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0089] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0090] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A Venturi separator, characterized in that the Venturi separator comprises a Venturi tube and a liquid collection tube surrounding at least a portion of the structure of the Venturi tube, the Venturi tube comprising the following sections connected in sequence: optionally a constant diameter section, a narrowing section, a throat, and an expanding section, the Venturi separator having a gas inlet, a liquid inlet, a liquid outlet, and a gas outlet, wherein an opening is provided on the side wall of the expanding section of the Venturi tube or at the end of the expanding section, the opening leading to the liquid collection tube, a liquid injection port on the wall of the Venturi tube is provided in the narrowing section of the Venturi tube so that liquid phase input from the liquid inlet of the Venturi separator is injected into the narrowing section of the Venturi tube, and the Venturi separator further comprises means for allowing gas to enter the Venturi tube in a helical flow manner or for allowing gas to enter the Venturi tube tangentially.

2. The Venturi separator according to claim 1, characterized in that the distance between the liquid phase injection port and the throat is 1 / 10-2 / 3 of the length of the narrowed section.

3. The Venturi separator according to any one of claims 1-2, characterized in that a nozzle may be provided at the liquid phase injection port on the wall of the Venturi tube.

4. The Venturi separator according to any one of claims 1-2, characterized in that the liquid phase inlet of the Venturi separator is connected to the liquid phase injection port on the wall of the Venturi tube via a delivery pipe passing through the wall of the liquid phase collection pipe, wherein the angle between the delivery pipe and the conical generatrix of the reduced diameter section of the Venturi tube located below the delivery pipe is 10-90°.

5. The Venturi separator according to any one of claims 1-2, characterized in that the top of the liquid phase collection tube is closed and provided with an open tube for the gas phase discharge of the Venturi separator, the upper outlet of the open tube forming the gas phase outlet of the Venturi separator, the open tube extending downward through the top of the liquid phase collection tube to the end of the expanded section of the Venturi tube, optionally a gap is provided between the lower end of the open tube and the end of the expanded section of the Venturi tube to form the liquid phase outlet.

6. The Venturi separator according to any one of claims 1-2, characterized in that the diameter of the opening pipe is greater than or equal to the diameter of the end opening of the expansion section.

7. The Venturi separator according to any one of claims 1-2, characterized in that the diameter of the liquid phase collection tube is larger than the maximum diameter of the Venturi tube disposed therein.

8. The Venturi separator according to any one of claims 1-2, characterized in that the liquid phase enters the Venturi tube through the liquid phase inlet in a tangential direction relative to the horizontal circumference of the Venturi tube.

9. The Venturi separator according to any one of claims 1-2, characterized in that the device for causing gas to flow in a spiral manner in the Venturi tube is a vortex core tube, the vortex core tube is provided with a spiral guide vane inside, the vortex core tube is provided at the inlet of the reduced diameter section of the Venturi tube or in the equal diameter section of the Venturi tube, and the bottom inlet of the vortex core tube is formed as the gas phase inlet of the Venturi separator or communicates with the gas phase inlet of the Venturi separator.

10. The Venturi separator according to any one of claims 1-2, characterized in that the number of eddy current core tubes is one or more.

11. The Venturi separator according to any one of claims 1-2, characterized in that a structure for guiding the helical flow of gas is provided on the inner wall of any of the optional constant diameter section, reduced diameter section, throat and expanded diameter section of the Venturi tube.

12. The Venturi separator according to claim 11, characterized in that the swirl vane or helical guide vane is selected from a single-head swirl vane or a single-head helical guide vane or a multi-head swirl vane or a multi-head helical guide vane having a number of threaded heads n, wherein n is a positive integer greater than 1.

13. The Venturi separator according to claims 1-11, characterized in that the bottom of the liquid phase collection tube is connected to the liquid discharge pipe, wherein a liquid seal is provided at the bottom of the liquid phase collection tube.

14. The Venturi separator according to claim 1, characterized in that the distance between the liquid phase injection port and the throat is 1 / 6 to 1 / 2 of the length of the narrowing section; the diameter of the opening pipe is equal to the diameter of the end opening of the widening section; and the diameter of the liquid phase collection pipe is 30% larger than the maximum diameter of the Venturi tube disposed therein.

15. The Venturi separator according to any one of claims 1-2, characterized in that the number of vortex core tubes is multiple, and the multiple vortex core tubes are arranged in parallel.

16. The Venturi separator according to claim 11, characterized in that the structure is selected from swirl vanes or helical guide vanes.

17. The use of the Venturi separator according to any one of claims 1-16, for multiphase separation in chemical processes.

18. The use according to claim 17, wherein it is used for gas separation of liquid components and washing or extraction separation of gas components.

19. The use according to claim 17, wherein the Venturi separator is used to wash away liquid phase components in a gas with a washing liquid, wherein the volume flow ratio of the gas to the washing liquid is 70-2500:1, and the obtained liquid phase removal rate can be 82%~99.9%.

20. In the application according to claim 17, the inlet gas velocity of the Venturi separator is 1 m / s to 40 m / s; the pressure loss of the Venturi separator is 0.1 kPa to 10 kPa; and / or, the absolute pressure of the liquid phase at the liquid phase injection port is 180 kPa to 1500 kPa.

21. The use according to claim 17, wherein the Venturi separator is used to wash away liquid phase components in a gas with a washing liquid, wherein the volume flow ratio of the gas to the washing liquid is 200-1100:1, and the obtained liquid phase removal rate can be 90-99.9%.

22. In the application according to claim 20, the inlet gas velocity of the Venturi separator is 5 m / s to 35 m / s; the pressure loss of the Venturi separator is 0.2 kPa to 5 kPa.

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