Venturi separator and use thereof

Abstract

The invention relates to a Venturi separator, characterized in that the Venturi separator comprises a Venturi tube and a liquid phase collecting tube surrounding at least a part of the structure of the Venturi tube. The Venturi tube comprises the following sections which are sequentially communicated: an optional equal-diameter section, a diameter-reducing section, a throat part and a diameter-expanding section. The Venturi separator is provided with a gas phase inlet, a liquid phase inlet, a liquid phase outlet and a gas phase outlet. An opening is formed in the side wall of the diameter-expanding section or the tail end of the diameter-expanding section of the Venturi tube. The opening leads to the liquid phase collecting tube, so that the liquid phase leaves the Venturi tube under the action of centrifugal force and enters the liquid phase collecting tube. The invention also relates to a use of the Venturi separator in a chemical process.

Description

A Venturi separator and its use Technical Field

[0001] The present invention relates to the field of chemical separation, in particular to the field of petrochemical aromatics separation, and specifically to a Venturi separator and application thereof. Background Art

[0002] Chemical separation technology is a crucial element in chemical engineering. Whether it's petroleum refining, plastics and chemical fibers, hydrometallurgy, isotope separation, or the refinement of bioproducts, the preparation of nanomaterials, flue gas desulfurization, or the production of fertilizers and pesticides, chemical separation technology is essential. The vast majority of raw materials and products in chemical production are mixtures, requiring separation and purification by exploiting the differences in the physical properties of the components within the system or with the aid of separating agents. Common separation methods used in chemical production can be categorized as mechanical separation and mass transfer separation. Mechanical separation methods simply separate the phases, using simple mechanical methods without any transfer of mass between them. Examples include filtration, sedimentation, centrifugation, cyclone separation, and electrostatic precipitation. Mass transfer separation methods, on the other hand, are used to separate homogeneous mixtures and are characterized by the presence of mass transfer.

[0003] Separation devices utilizing the Venturi tube principle, such as wet Venturi dust collectors, have been disclosed in the prior art. Wet Venturi dust collectors utilize negative pressure in the gas phase to create a uniform water film in the liquid phase. The smoke-carrying airflow enters the Venturi separator tangentially and passes through the Venturi throat, where scrubbing liquid is sprayed. The airflow is rapidly accelerated in the throat, resulting in the relative motion of the airflow and liquid, which mixes thoroughly, allowing the smoke or pollutants to aggregate with the liquid droplets.

[0004] CN104226074A discloses an acidic tail gas scrubbing device, which includes a condenser, a venturi tube, and a phase separator. The upper end of the venturi serves as an air inlet, while the lower end of the venturi serves as a discharge port. The air inlet of the venturi is connected to the air outlet of the condenser. A water inlet pipe is tangentially connected to the upper portion of the venturi, allowing scrubbing water to enter the upper portion of the venturi tangentially. However, this acidic tail gas scrubbing device has a complex structure, consisting of multiple components and occupying a large area.

[0005] CN108525443A discloses a Venturi decontamination device for gas-liquid treatment, comprising an air inlet pipe, a liquid inlet, a Venturi contraction tube, and a Venturi expansion tube. The two ends of the Venturi contraction tube are connected to the air inlet pipe and the Venturi expansion tube, respectively. The liquid inlet is located at the junction of the Venturi contraction tube and the Venturi expansion tube.

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

[0007] However, the separation system using a venturi tube in the prior art usually requires one or more other devices such as a phase separator to be used in series, resulting in a low degree of equipment integration, which makes the system occupy a large area and has a high investment cost.

[0008] To this end, the purpose of the present invention is to provide a Venturi separator suitable for use in 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.

[0009] Summary of the Invention

[0010] After in-depth research, the inventors surprisingly discovered that in a multiphase separation method in a chemical process, by combining a venturi tube with the spiral flow of a fluid, both mass transfer separation and mechanical separation can be achieved simultaneously, i.e., multiphase fluid mixing and separation can be achieved quickly and efficiently. Furthermore, by creatively positioning the venturi tube within a liquid phase collection tube and positioning the fluid entry point, the spiral flow characteristics of the fluid in the venturi tube can be fully utilized to achieve continuous, enhanced mixing and separation between the multiphase fluids, thereby efficiently achieving mass transfer and separation between the multiphase fluids. Furthermore, the ingenious combination of the venturi tube and the liquid phase collection tube makes the venturi separator simple and compact, eliminating subsequent equipment (such as a phase separator), saving space, and occupying a small area, making it suitable for use in combination with various other chemical equipment, such as a distillation column, and reducing investment costs. Furthermore, the inventors discovered that the use of a vortex core tube in the venturi separator of the present invention can quickly achieve high-speed spiral flow of gas in the venturi tube.

[0011] In order to achieve the above-mentioned purpose, according to a first aspect of the present invention, there is provided 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 comprises the following sections connected in sequence: an optional constant diameter section, a reduced diameter section, a throat and an expanded diameter section, the venturi separator has 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 expanded diameter section of the venturi tube or at the end of the expanded diameter section, so that the liquid phase leaves the venturi tube and enters the liquid phase collection tube under the action of centrifugal force.

[0012] According to a second aspect of the present invention, the present invention also relates to the use of the Venturi separator of the first aspect, which is used for multiphase separation in chemical processes, especially for gas-liquid separation integrated into organic compounds.

[0013] The Venturi separator according to the present invention has the following advantages: its structural design is ingenious, the arrangement of its components is reasonable and compact, it can be operated continuously, has high separation efficiency, occupies a small area, saves space, has low investment cost, and can be used in combination with other devices such as distillation towers in chemical production. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to illustrate the technical solutions of the present invention and constitute part of the specification, but do not limit the present invention.

[0015] FIG1 shows a schematic diagram of an aromatics extraction system involved in Example 1 of the present invention.

[0016] FIG2 shows a schematic structural diagram of a Venturi separator according to an embodiment of the present invention used in Example 1. FIG.

[0017] Description of Reference Numerals

[0018] In Figure 1, 101: aromatics extraction distillation tower; 102: venturi separator; 103: reflux drum; 104: condenser; 1: aromatics feed inlet; 2: extraction solvent inlet; 3: tower top gas phase outlet; 4: washed gas outlet; 5: reflux drum inlet; 6: washing liquid inlet; 7: raffinate oil product outlet; 8: washing liquid outlet; 9: tower bottom liquid phase outlet; 10: side line inlet; 11: tower top gas phase inlet; 12: water phase outlet.

[0019] In FIG2 , 13 : vortex core tube; 14 : Venturi tube; 15 : washing liquid inlet tube; 16 : liquid phase collecting tube; 17 : top opening of the expanded diameter section; 18 : open tube. DETAILED DESCRIPTION

[0020] The specific embodiments of the present application are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the technical solutions of the present invention and are not intended to limit the present invention.

[0021] Any specific numerical value disclosed in this specification (including the endpoints of a numerical range) is not limited to the exact value of the numerical value, but should be understood to also include values ​​close to the exact value, such as all possible values ​​within the range of ±5% of the exact value. Moreover, for a disclosed numerical range, the values ​​between the endpoints of the range, between the endpoints and the specific points in the range, and between the specific points can be arbitrarily combined to form one or more new numerical ranges, and these new numerical ranges should also be considered to be specifically disclosed in this specification.

[0022] Unless otherwise specified, the terms used in this specification have the same meanings as commonly understood by those skilled in the art. If a term is defined in this specification and its definition is different from the common understanding in the art, the definition in this document shall prevail.

[0023] In this application, except for the contents explicitly stated, any matters or items not mentioned are directly applicable to those known in the art without any changes. Moreover, any embodiment described herein can be freely combined with one or more other embodiments described herein, and the technical solutions or technical ideas formed thereby are considered part of the original disclosure or original description of the present invention, and should not be regarded as new content not disclosed or anticipated herein, unless a person skilled in the art considers that the combination is obviously unreasonable.

[0024] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or its synonyms such as “comprising” or “containing”, etc., will be understood to include stated elements or components but not to exclude other elements or components.

[0025] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the orientation terms "length", "angle", "above", "below", "vertical", "upright", "horizontal", "top", "bottom", "inside", "outside", "tangential", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] In the present specification, unless otherwise specified or limited, the terms "disposed," "connected," "connected," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed or detachable connections, or integration; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0027] According to a first aspect of the present invention, the present invention provides a venturi separator, characterized in that the venturi separator includes a venturi tube and a liquid phase collection pipe surrounding at least a portion of the structure of the venturi tube, the venturi tube includes the following sections connected in sequence: an expanded diameter section, a throat, a reduced diameter section and an optional constant diameter section, the venturi separator has 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 expanded diameter section of the venturi tube or at the end of the expanded diameter section and leads to the liquid phase collection pipe, so that the liquid phase leaves the venturi tube and enters the liquid phase collection pipe under the action of centrifugal force.

[0028] According to one embodiment of the first aspect above, the venturi separator is placed upright, and its gas phase inlet and liquid phase inlet are optionally connected to other devices to continuously process gas and liquid from other devices, and the liquid phase outlet and gas phase outlet are also optionally connected to other devices for subsequent processing or storage.

[0029] According to one embodiment of the first aspect above, the venturi tube optionally includes a constant diameter section, which is connected to the reduced diameter section (if any), and can be used to connect to other equipment or install auxiliary equipment therein, such as a vortex core tube; the throat is the connecting part of the reduced diameter section and the expanded diameter section, and has the smallest diameter in the venturi tube. It can also be a section of constant diameter pipe connecting the reduced diameter section and the expanded diameter section, and an opening for gas and liquid to leave the venturi tube is provided in the expanded diameter section or at the top of the expanded diameter section, and the optional constant diameter section, reduced diameter section, throat and expanded diameter section are connected from bottom to top.

[0030] According to one embodiment of the first aspect, a liquid phase injection port is provided on the wall of the reduced diameter section of the Venturi tube. Specifically, the liquid phase input from the liquid phase inlet of the Venturi separator is injected into the Venturi tube in the reduced diameter section, where it comes into contact and mixes with the spirally flowing gas in the Venturi tube. Because the gas flows at high speed in a spiral manner within the reduced diameter section of the Venturi tube, the angular velocity of the spiral flow of the gas increases as the diameter of the reduced diameter section decreases. Therefore, when the liquid phase is injected into the Venturi tube in the reduced diameter section, it flows and mixes with the spirally flowing gas, increasing the degree of liquid disturbance and the gas-liquid mixing. This results in more complete mass transfer between the gas and liquid, and better separation. The liquid phase injection port on the wall of the Venturi tube can be located anywhere within the reduced diameter section. Preferably, the distance between the liquid phase injection port and the throat is 1 / 10 to 2 / 3 of the reduced diameter section length, and more preferably, the distance between the liquid phase injection port and the throat is 1 / 8 to 1 / 2 of the reduced diameter section length.

[0031] According to one embodiment of the first aspect above, a nozzle may 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 to accelerate the mixing of the gas and liquid. The injection flow rate and speed of the liquid phase can be adjusted by those skilled in the art according to actual needs and the gas flow rate and flow rate. The injection direction of the nozzle can be in 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 at an angle of less than 60°, more preferably at an angle of less than 30°, for example, at an angle of less than 15°, and more preferably in the same direction as the gas flow direction.

[0032] According to one embodiment of the first aspect, the liquid-phase collection tube surrounds at least a portion of the Venturi tube's structure at its periphery, for example, at least surrounding the sidewall of the expanded diameter section of the Venturi tube or an opening at the end of the expanded diameter section. The liquid-phase collection tube extends downward, encompassing the expanded diameter section of the Venturi tube, and may even encompass the throat and reduced diameter section, or even the entire Venturi tube. Preferably, the Venturi separator of the present invention includes a liquid-phase collection tube and a Venturi tube disposed within the liquid-phase collection tube. If the liquid phase collection pipe surrounds the entire venturi tube, then the liquid infusion pipe for conveying the liquid phase connected to the liquid phase injection port on the wall of the venturi tube needs to pass through the liquid phase collection pipe wall. At this time, the liquid phase inlet of the venturi separator is connected to the liquid phase injection port on the wall of the venturi tube via the liquid infusion pipe passing through the liquid phase collection pipe wall, wherein the angle between the liquid infusion pipe and the conical busbar of the reduced diameter section of the venturi tube located below the liquid infusion pipe can be 10-90°, preferably 30-80°, for example 40°, 50°, 60° or 70°.

[0033] According to an embodiment of the first aspect above, the top of the liquid phase collecting tube is closed, but is provided with an open tube for discharging the gas phase of the venturi separator, the upper end outlet of the open tube forming the gas phase outlet of the venturi separator, and the open tube passes downward through the top of the liquid phase collecting tube and extends to the end of the expanded diameter section of the venturi tube. If an opening for the liquid phase to exit the Venturi tube is provided on the sidewall of the expanded section of the Venturi tube, the open tube is connected to the end of the expanded section of the Venturi tube, and optionally, a liquid phase outlet is provided between the lower end of the open tube and the end of the expanded section of the Venturi tube for discharging liquid that is not discharged at the outlet of the expanded section. If the opening for the liquid phase to exit the Venturi tube is provided at the end of the expanded section of the Venturi tube, the lower end of the open tube and the end of the expanded section of the Venturi tube are completely or partially separated to form an opening for the liquid phase to exit the Venturi tube. Thus, the opening is a continuous or discontinuous annular opening, and the height of the opening can be adjusted by raising or lowering the open tube. The height of the opening can be varied within a certain range depending on the liquid phase flow rate, as long as it allows substantially all of the liquid phase to exit the Venturi tube under the action of centrifugal force and enter the liquid phase collection tube, while preventing a significant amount of gas from entering the liquid phase collection tube. For example, the height of the opening is less than 10 centimeters, such as less than 5 centimeters.

[0034] According to one embodiment of the first aspect above, the diameter of the open tube can be slightly larger than the diameter of the end opening of the expanded section. For example, the diameter of the open tube is less than 5% larger than the diameter of the end opening of the expanded section. Preferably, the diameter of the open tube is the same as the diameter of the end opening of the expanded section.

[0035] According to one embodiment of the first aspect, the Venturi separator further includes a device for causing gas to enter the Venturi tube in a spiral flow pattern, or a device for causing gas to enter the Venturi tube tangentially, so that the gas flows upward in a spiral pattern within the Venturi tube. The device is positioned at the entrance of the reduced diameter section of the Venturi tube, or within the constant diameter section of the Venturi tube. The device for causing gas to generate a spiral flow within the Venturi tube can be a device commonly used in the art, such as a vortex core tube.

[0036] According to an embodiment of the first aspect above, the device for making the gas flow in a spiral manner in the venturi tube is a vortex core tube, and a spiral guide plate is provided inside the vortex core tube. The vortex core tube is arranged at the entrance 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.

[0037] According to an embodiment of the first aspect, the number of the vortex core tubes can be selected according to actual needs (such as gas flow rate, etc.), and can be one or more. If multiple vortex core tubes are used, the multiple vortex core tubes can be arranged in parallel.

[0038] According to one embodiment of the first aspect, the diameter of the liquid-phase collection pipe is larger than the maximum diameter of the venturi tube disposed therein. Those skilled in the art may select a diameter based on actual needs and site conditions. Preferably, the diameter of the liquid-phase collection pipe is 30% larger than the maximum diameter of the venturi tube disposed therein, preferably 20% larger, for example, 10% or 5% larger.

[0039] According to one embodiment of the first aspect described above, structures for guiding gas spiral flow are provided on the inner walls of any of the constant-diameter, reduced-diameter, throat, and expanded-diameter sections of the Venturi tube, allowing the gas flow or gas-liquid flow to spiral upward or downward along the inner wall of the Venturi tube. These structures can be selected from swirl blades or spiral guide vanes, which can increase the tangential velocity of the fluid, prevent the fluid from adhering to the wall, enhance contact between the gas and liquid, and further improve the separation efficiency of the Venturi separator. The helical pitch angle φ of the swirl blades or spiral guide vanes can be selected by those skilled in the art based on actual conditions and adjusted according to changes in the diameter of the Venturi tube.

[0040] According to a preferred embodiment, the swirl blade or spiral guide vane can be a single- or multi-head swirl blade or a single- or multi-head spiral guide vane with a number of thread heads n (n is a positive integer greater than or equal to 1). If the swirl blade or spiral guide vane is multi-headed, and the pitch of the multi-head swirl blade or multi-head spiral guide vane (n>1) is the same as the pitch of the single-head swirl blade or single-head spiral guide vane (n=1), since the helix angle φ of the multi-head spiral guide vane is approximately n times the helix angle φ of the single-head spiral guide vane, the multi-head spiral 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.

[0041] According to one embodiment of the first aspect above, in the Venturi separator, the volume 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 1m / s~40m / s, preferably 5m / s~35m / s; the pressure loss of the Venturi separator is less than 20kPa, for example, 0.1kPa~10kPa, preferably 0.2kPa~5kPa; the absolute pressure of the liquid phase at the liquid phase injection port is above 170kPa, preferably 180kPa~1500kPa, preferably 200~1000kPa, and more preferably 250~700kPa.

[0042] According to an embodiment of the first aspect above, in the Venturi separator, the bottom of the liquid phase collecting 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 collecting tube to prevent gas from entering the liquid discharge pipe.

[0043] According to a second aspect of the present invention, the present invention also relates to use of the Venturi separator for liquid-gas separation or liquid-gas purification.

[0044] 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 separation or extractive separation of gas components in the gas phase, for example, using a washing liquid to elute the solvent contained in the gas from the top of the distillation column.

[0045] 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 = the weight of the liquid phase entering the liquid phase collection pipe / the total weight of the liquid phase injected into the venturi tube.

[0046] The following examples are provided to further illustrate the beneficial effects of the technical solutions of the present invention, but are by no means intended to limit the scope of the present invention.

[0047] In these examples, 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 the aromatic extraction distillation column.

[0048] The aromatics raw material used in the aromatics extraction system involved in the examples and comparative examples is the C6-C7 fraction of reformed oil, and the mass fraction of aromatics in the aromatics raw material is 65%.

[0049] The sulfolane used was a chemical reagent purchased from Inokai Technology Co., Ltd. Unless otherwise specified, the other reagents were obtained through commercial channels.

[0050] Example 1

[0051] In this embodiment, an aromatics extraction system as shown in FIG. 1 and a venturi separator as shown in FIG. 2 are used. The system includes an aromatics extraction distillation column 101 , a venturi separator 102 , a reflux drum 103 and a condenser 104 .

[0052] The aromatics extraction distillation tower 101 includes an aromatics feed inlet 1, an extraction solvent inlet 2, a side line inlet 10, a liquid phase outlet 9 at the bottom of the tower and a gas phase outlet 3 at the top of the tower; the venturi separator 102 includes a gas phase inlet 11, a liquid phase (washing water in this embodiment) inlet 6, a washing liquid (washing water in this embodiment) outlet 8 and a gas phase (washed gas in this embodiment) outlet 4; the reflux tank 103 includes a reflux tank inlet 5, a water phase outlet 12 and an oil phase outlet 7.

[0053] The overhead gas phase outlet 3 of the aromatics extractive distillation column 101 is connected to the gas phase inlet 11 of the venturi separator 102; the wash liquid (wash water in this embodiment) outlet 8 of the venturi separator 102 is connected to the side line inlet 10 of the aromatics extractive distillation column 101, and the gas phase (washed gas) outlet 4 of the venturi separator 102 is connected to the inlet 5 of the reflux drum 103; the water phase outlet 12 of the reflux drum 103 is connected to the liquid phase (wash water in this embodiment) inlet 6 of the venturi separator 102; the oil phase outlet 7 of the reflux drum 103 forms the raffinate oil product outlet of the system; and 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 drum.

[0054] The venturi separator 102 includes a liquid phase collecting pipe 16 arranged upright and a venturi tube 14 arranged upright in the liquid phase collecting pipe 16, and a liquid phase injection port (also referred to as a washing liquid injection port in this embodiment) is provided at the upper 1 / 3 of the reduced diameter section near the throat of the venturi tube 14; the venturi separator includes a venturi tube 14, a vortex core tube 13, a washing liquid input pipe 15 and a liquid phase collecting pipe 16; the washed gas outlet 4 of the venturi separator 102 is arranged at the top of the liquid phase collecting pipe 16; the liquid phase inlet 6 of the venturi separator 102 is connected to the washing liquid injection port below the throat of the venturi tube 14 through the washing liquid input 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, and 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, The washing liquid inlet pipe 15 passes through the wall of the liquid phase collecting pipe 16 and is connected to the washing liquid injection port on the diameter reduction section of the venturi tube 14, and is close to the throat of the venturi tube; the top of the liquid phase collecting pipe 16 is provided with an open pipe 18, the top opening of the open pipe 18 can also serve as the washed gas outlet 4 of the venturi separator 102, and the bottom opening of the open pipe 18 passes downward through the top of the liquid phase collecting pipe and extends to The liquid phase collecting pipe 16 is spaced apart from the top of the expanded diameter section of the venturi tube 14 to form an opening 17; the diameter of the opening pipe 18 is the same as the diameter of the top opening of the expanded diameter section; the angle between the washing liquid input pipe 15 and the axis of the venturi tube 14 is 90°; the vortex core tube 13 is arranged in the equal diameter section of the venturi tube, and the bottom inlet of the vortex core tube 13 can also serve as the gas phase inlet 11 of the venturi separator 102; the number of vortex core tubes is one.

[0055] Aromatic raw materials enter the aromatic extraction distillation tower 101 through the aromatic raw material inlet 1, and the solvent sulfolane enters the aromatic extraction distillation tower 101 through the extraction solvent inlet 2. The aromatic raw materials and sulfolane contact in the aromatic extraction distillation tower 101 to extract aromatics; the top gas of the aromatic extraction distillation tower 101 is discharged from the top gas phase outlet 3, passes through the vortex core tube 13 of the venturi separator 102, forms an upward vortex flow of gas, and enters the venturi tube 14; the water phase from the reflux tank 103 is sprayed into the venturi tube 14 through the washing liquid inlet pipe 15; the vortex flow of gas contacts the washing liquid and undergoes water washing and removal treatment, and the gas and the washing liquid are discharged along the wall of the venturi tube. Continuing its upward spiral flow, scrubbed gas and solvent-containing scrubbing liquid are produced. In the expanded section, centrifugal force gradually gathers the solvent-containing scrubbing liquid outside the vortex. Under the action of centrifugal force, this solvent-containing scrubbing liquid is discharged from the opening between the bottom end of open tube 18 and the top of the expanded section, entering liquid collection pipe 16. Under the action of gravity, it reaches scrubbing liquid outlet 8 at the bottom of the venturi separator and is discharged. The scrubbed gas is discharged from scrubbed gas outlet 4, passes through condenser 104, and then enters reflux drum 103 for treatment. Raffinate oil is discharged from reflux drum 103's oil phase outlet 7. The liquid phase discharged from scrubbing liquid outlet 8 is returned to the aromatics extraction distillation column 101 for recycling. The liquid phase removal rate at the top gas phase outlet of the venturi separator 102 is 99.8%. Specific operating conditions of the aromatics extraction system are shown in Table 1.

[0056] Example 2

[0057] The method was identical to that of Example 1, except that the Venturi tube in this embodiment did not include a vortex core. Instead, the gas was introduced tangentially to the inner wall of the Venturi tube inlet, with an inlet gas velocity of 40 m / s. The liquid removal rate at the top gas phase outlet of Venturi separator 102 was 83%. Specific operating conditions for the aromatics extraction system are shown in Table 1.

[0058] Example 3

[0059] The method is the same as that in Example 1, except that the volume flow ratio of the gas phase to the scrubbing liquid in this embodiment is 1200:1; the liquid phase removal rate at the top gas phase outlet of the venturi separator 102 is 99.8%, and the specific operating conditions of the aromatics extraction system are shown in Table 1.

[0060] Example 4

[0061] The method is the same as that of 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 top gas phase outlet of the venturi separator 102 is 95%. The specific operating conditions of the aromatics extraction system are shown in Table 1.

[0062] Example 5

[0063] The method is the same as that in Example 1, except that in this embodiment, the distance between the liquid phase injection port and the throat of the venturi tube is 2 / 3 of the length of the reduced diameter section, and the absolute pressure of the washing liquid at the liquid phase injection port is 500 kPa; the liquid phase removal rate at the top gas phase outlet of the venturi separator 102 is 99.8%. The specific operating conditions of the aromatics extraction system are shown in Table 1.

[0064] Example 6

[0065] The method is the same as that in Example 1, except that in this embodiment, the liquid phase injection port is located at the throat of the venturi tube, the volume flow ratio of the gas phase to the scrubbing liquid is 1200, and the absolute pressure of the scrubbing liquid at the liquid phase injection port is 250 kPa; the liquid phase removal rate at the top gas phase outlet of the venturi separator 102 is 95%. The specific operating conditions of the aromatics extraction system are shown in Table 1.

[0066] Table 1

[0067] Comparative Example 1

[0068] The conventional process shown in Figure 1 was used, but a non-aromatic distillation column (NA column) was used instead of the Venturi separator. That is, the extractive distillation column (ED column) and the non-aromatic distillation column (NA column) were connected in series to recover trace solvents in the ED column top gas. The raw materials, solvents, and solvent ratios used were the same as those in Example 1. The operating conditions of this comparative example 1 are shown in Table 2.

[0069] Table 2

[0070] Comparative Example 2

[0071] The process shown in Figure 1 was used, but a non-aromatic distillation section was used instead of a Venturi separator. That is, a non-aromatic distillation section was set in the upper section of the extractive distillation column (ED column) to recover trace solvents in the raffinate oil. The raw materials, solvents, and solvent ratios were the same as in Example 1. The operating conditions are shown in Table 3.

[0072] Table 3

[0073] Test Example 1

[0074] The components of the raffinate oil products obtained in Examples 1 to 4 and Comparative Examples 1 to 2 were analyzed. The aromatic content and solvent content of the raffinate oil were analyzed by ASTM D-6536 and GGBM-04-2005 standard methods. The product composition is shown in Table 4.

[0075] Table 4

[0076] According to the data in Table 4, the aromatics extraction system including the venturi separator according to the present invention significantly increased the content of non-aromatic hydrocarbons in the raffinate oil, significantly reduced the content of aromatic hydrocarbons in the raffinate oil, and further improved the quality and yield of the aromatic hydrocarbon product in the extract. This shows that the venturi separator according to the present invention can be combined with an aromatics extraction distillation tower, so that the aromatics extraction distillation tower can efficiently separate organic compounds such as aromatics in the gas phase. In addition, the venturi separator according to the present invention occupies a small area and does not require additional heating, further reducing energy consumption.

[0077] By comparing Example 1 with Comparative Example 1, it can be seen that the solvent (sulfolane) content in the raffinate oil 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, in the aromatic extraction distillation tower of the present invention, the addition of the aqueous phase from the venturi separator improves the solvent selectivity, resulting in a lower aromatic content in the raffinate oil, and no reboiler at the bottom of the NA tower and no reflux at the top of the tower are required, thereby saving energy consumption.

[0078] By comparing Example 1 with 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-aromatic hydrocarbons in the raffinate oil, reduces the content of aromatic hydrocarbons in the raffinate oil, and further increases the yield of aromatic hydrocarbons in the extract; at the same time, it improves the effect of solvent removal in the raffinate oil.

[0079] By comparing Example 1 with Example 2, it can be seen that when the Venturi separator of the present invention uses a vortex core tube, the liquid phase removal rate is higher than that using a tangential air intake method, and the residual solvent content in the raffinate oil product is significantly lower.

[0080] By comparing Example 1 with Example 3, it can be seen that within the volume flow ratio range of the overhead gas phase / washing liquid within the preferred range of the present invention, the solvent content in the raffinate oil product is lower.

[0081] By comparing Example 1 with Example 4, it can be seen that, within the range of the gas velocity at the venturi tube inlet and the absolute pressure at the liquid phase injection port of the present invention, the liquid phase removal rate is significantly higher and the residual solvent content in the raffinate oil product is lower.

[0082] By comparing Example 1 with Example 5, it can be seen that, within the range of the gas velocity at the venturi tube inlet and the absolute pressure at the liquid phase injection port of the present invention, when the distance between the liquid phase injection port and the throat is 2 / 3 of the length of the reduced diameter section, the pressure drop caused by the injection of the liquid phase is significantly higher than the pressure drop caused by the liquid phase when the distance between the liquid phase injection port and the throat is 1 / 3 of the length of the reduced diameter section. A higher pressure is required at the top of the extractive distillation tower to maintain the same gas velocity, but the separation effects of the two are comparable, indicating that by injecting the washing liquid at a position within the preferred range of the present invention, the extractive distillation tower can maintain optimal operating conditions.

[0083] By comparing Example 1 with Example 6, it can be seen that, within the range of the gas velocity at the inlet of the venturi tube of the present invention and the absolute pressure at the liquid phase injection port, the separation effect produced by the liquid phase being injected at the reduced diameter section is much higher than the separation effect produced by the liquid phase being injected at the throat. This is because when the liquid phase is injected at the throat, it does not experience the reduced diameter section, resulting in insufficient gas-liquid mixing, and the ratio of the volume flow rates of the gas phase to the washing liquid is large, so that the solvent in the gas is less washed by the liquid phase, and therefore the residual solvent content in the raffinate oil product is higher.

[0084] By comparing Example 1 with Example 6, it can be seen that within the range of the gas velocity at the venturi tube inlet and the absolute pressure at the liquid phase injection port of the present invention, since the liquid phase is injected at a lower position in the reduced diameter section, less liquid phase can be injected when processing gas at the same velocity, resulting in a lower gas processing efficiency and a higher solvent residual content in the raffinate oil product.

[0085] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within 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 scope of protection of the present invention.

[0086] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0087] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A venturi separator, characterized in that the venturi separator comprises a venturi tube and a liquid phase collecting tube surrounding at least a part of the structure of the venturi tube, the venturi tube comprises the following sections connected in sequence: an optional equal diameter section, a reduced diameter section, a throat and an expanded diameter section, the venturi separator has 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 expanded diameter section of the venturi tube or at the end of the expanded diameter section, and the opening leads to the liquid phase collecting tube.

2. The Venturi separator according to claim 1 is characterized in that the liquid phase injection port on the tube wall of the Venturi tube is arranged in the reduced diameter section of the Venturi tube, preferably, the distance between the position of the liquid phase injection port and the throat is 1 / 10-2 / 3 of the length of the reduced diameter section, and more preferably, the distance between the position of the liquid phase injection port and the throat is 1 / 6-1 / 2 of the length of the reduced diameter section.

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

4. A venturi separator according to any one of claims 1-3, 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 liquid infusion pipeline that optionally passes through the liquid phase collection tube wall, wherein the angle between the liquid infusion pipeline and the conical generatrix of the reduced diameter section of the venturi tube located below the liquid infusion pipeline is 10-90°, preferably 30-80°, and preferably, the liquid phase enters the venturi tube through the liquid phase injection port in a tangential direction relative to the horizontal circumference of the venturi tube.

5. The venturi separator according to any one of claims 1-4 is characterized in that the top of the liquid phase collecting tube is closed and is provided with an open tube for discharging the gas phase of the venturi separator, the upper end outlet of the open tube forming the gas phase outlet of the venturi separator, the open tube passes through the top of the liquid phase collecting tube and extends downward to the end of the expanded diameter section of the venturi tube, and optionally a gap is provided between the lower end of the open tube and the end of the expanded diameter section of the venturi tube to form a liquid phase outlet.

6. The Venturi separator according to any one of claims 1-5, characterized in that the diameter of the open tube is greater than or equal to the diameter of the end opening of the expanded section, preferably the diameter of the open tube is equal to the diameter of the end opening of the expanded section.

7. A Venturi separator according to any one of claims 1-6, characterized in that the diameter of the liquid phase collecting pipe is larger than the maximum diameter of the Venturi tube arranged therein, preferably, the diameter of the liquid phase collecting pipe is 30% larger than the maximum diameter of the Venturi tube arranged therein, for example, 10% or 5%.

8. The Venturi separator according to any one of claims 1 to 7, characterized in that the Venturi separator further comprises a device for allowing the gas to enter the Venturi tube in a spiral flow manner or a device for allowing the gas to enter the Venturi tube tangentially.

9. A Venturi separator according to any one of claims 1 to 8, characterized in that the device for making the gas flow in a spiral manner in the Venturi tube is a vortex core tube, a spiral guide vane is arranged inside the vortex core tube, the vortex core tube is arranged at the entrance 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 is connected to the gas phase inlet of the Venturi separator.

10. The Venturi separator according to any one of claims 1 to 9, characterized in that the number of the vortex core tubes is one or more, preferably multiple, and the multiple vortex core tubes are arranged in parallel.

11. The Venturi separator according to any one of claims 1-10, characterized in that a structure for guiding the spiral flow of gas is provided on the inner wall of any of the equal-diameter section, reduced-diameter section, throat and expanded-diameter section of the Venturi tube; preferably, the structure is selected from swirl blades or spiral guide vanes.

12. A Venturi separator according to claim 11, characterized in that the swirl blade or spiral guide vane is selected from a single-start swirl blade or a single-start spiral guide vane or a multi-start swirl blade or a multi-start spiral guide vane with a number of thread 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 collecting pipe is connected to the liquid discharge pipe, wherein a liquid seal is provided at the bottom of the liquid phase collecting pipe.

14. Use of the Venturi separator according to any one of claims 1 to 13 for multiphase separation in chemical processes, preferably for stripping separation of liquid components and scrubbing separation or extractive separation of gas components.

15. The use according to claim 14, wherein the venturi separator is used to elute the liquid component in the gas phase by means of a washing liquid, the volume flow ratio of the gas phase to the washing liquid is 70-2500:1, preferably 200-1100:1, and the obtained liquid phase removal rate can be 82% to 99.9%, preferably 90 to 99.9%.

16. The use according to claim 14, wherein 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 0.1 kPa to 10 kPa, preferably 0.2 kPa to 5 kPa; and / or the absolute pressure of the liquid phase at the liquid phase injection port is 180 kPa to 1500 kPa.

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