Hybrid unit and hydrate process continuous gas separation system employing the same

Abstract

The application discloses a kind of mixed units and hydrate method continuous gas separation system using the unit, the mixed unit is applied to the process of hydrate method continuous gas separation, mixed unit is multistage setting, comprising: venturi mixer, inlet section receives cooled working fluid, throat section receives preset low-temperature high-pressure mixed gas, mixed gas and working fluid form vertical impact in throat section, for strengthening gas-liquid interphase transfer, gas-liquid mixture flows out from outlet steady section after mixing;Tubular reactor receives gas-liquid mixture from venturi mixer, the tubular reactor is uniformly spaced and arranged in hilly protrusion, gas-liquid mixture forms turbulent disturbance when flowing through protrusion, so that mixed gas and working fluid are further mixed and contacted to react, realize the generation of hydrate.The application is through multistage setting mixed unit, gas-liquid mixing is more sufficient, while reducing energy consumption, can effectively increase gas-liquid mass transfer, improve the generation rate of hydrate;Also can effectively solve the continuity problem in hydrate method gas separation process.

Description

Technical Field

[0001] This invention relates to the field of gas separation technology using hydrates, and particularly to a mixing unit and a continuous gas separation system using hydrates that applies the unit. Background Technology

[0002] Gas hydrates are ice-like crystalline compounds formed by gases and water under high pressure and low temperature. Because different gases form hydrates at different temperatures and pressures, the hydrate method becomes possible for gas separation. When two mixed gases, A and B, form hydrates, the component A, which readily forms hydrates, will form a hydrate slurry due to the different conditions for hydrate formation. The component B, which is less likely to form hydrates, will accumulate in the gas phase. The hydrate slurry is then decomposed to obtain gas A, thus achieving gas separation.

[0003] For example, Chinese patent application CN110229043A discloses a CH4 / CO2 separation device and method using a hydrate method. This device includes a gas source, a water source, and several separation stages. Both the gas and water sources are connected to the first stage of the separation process. The reaction temperature of the hydrate reactors in each stage is higher than 283K. This scheme, by setting up multiple separation stages and ensuring that the reaction temperature in the hydrate reactors of each stage is higher than 283K, achieves the separation of CH4 / CO2 while simultaneously obtaining solid CH4 hydrate and liquid CO2. This scheme simplifies the process flow and reduces equipment investment. However, although this scheme uses a multi-stage separation method, the gas-liquid mixing effect is insufficient, the hydrate formation rate is slow, energy consumption is high, and it is difficult to guarantee the gas separation effect at the downstream end of the multi-stage separation process.

[0004] While existing hydrate-based gas separation technologies, similar to those mentioned above, have been extensively studied, most are conducted using small-scale laboratory equipment. Current research often employs multi-stage separation methods, requiring significant pressure. This is because, in addition to pressure losses, each stage must maintain a pressure higher than the hydrate formation pressure to achieve gas separation, increasing energy consumption. Furthermore, some batch operations require two or more reactors for continuous gas purification, as the gas phase cannot be simultaneously extracted from the hydrate-forming reactor, disrupting continuous gas separation. Additionally, the aqueous solution used for hydrate formation is not recycled. Moreover, hydrate formation becomes increasingly demanding as the concentration of the target gas decreases. In conventional tubular reactors, the fluid is in a laminar flow state within the pipes, resulting in weak gas-liquid mass transfer, slow and insufficient hydrate formation, and inadequate gas separation.

[0005] Therefore, there is an urgent need for a hybrid unit and a continuous gas separation system using hydrates that employs this unit. By using a multi-stage continuous gas hydrate separation process, energy consumption can be reduced while increasing gas-liquid mass transfer and improving the hydrate formation rate. At the same time, it can effectively solve the continuity problem in the gas separation process using hydrates.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a mixing unit and a continuous gas separation system for hydrates using the device. Through the multi-stage mixing unit, gas-liquid mixing is more thorough, which can effectively increase gas-liquid mass transfer and improve the hydrate formation rate while reducing energy consumption.

[0008] Another objective of this invention is to effectively solve the continuity problem in the gas separation process using hydrates.

[0009] To achieve the above objectives, according to a first aspect of the present invention, a mixing unit is provided for use in a continuous gas separation process using hydrates. The mixing unit is multi-stage and includes: a Venturi mixer, the inlet section of which receives cooled working fluid, and a throat section which receives a preset low-temperature, high-pressure mixed gas. The mixed gas and working fluid collide vertically in the throat section to enhance the interphase transfer between gas and liquid. After mixing, the gas and liquid flow out from the outlet stable section; and a tubular reactor, which receives the gas-liquid mixture from the Venturi mixer. The tubular reactor has hill-shaped protrusions evenly spaced in it. When the gas-liquid mixture flows through the protrusions, it forms turbulent disturbances, allowing the mixed gas and working fluid to further mix, contact, and react, thereby generating hydrates.

[0010] Furthermore, in the above technical solution, the tubular reactor can be designed as a straight tube structure, and the reactor can be equipped with multiple layers of baffles extending along the axial direction, with multiple rows of hill-shaped protrusions arranged along the axial direction, and the protrusions in adjacent rows being staggered.

[0011] Furthermore, in the above technical solution, there can be two layers of partitions, with the two layers of partitions respectively arranged at 1 / 3 and 2 / 3 of the diameter from the bottom of the straight pipe.

[0012] Furthermore, in the above technical solution, a bath for temperature control can be provided outside the tubular reactor, and the working temperature of the bath is designed to be -20~90℃.

[0013] Furthermore, in the above technical solution, a transparent viewing window with a pressure resistance of 20MPa can be provided on the straight tube of the tubular reactor for observing the flow of the gas-liquid mixture and the formation of hydrates.

[0014] Furthermore, in the above technical solution, a dosing port can be provided at the inlet section of the Venturi mixer to pump the polymerization inhibitor into the mixer to prevent the solidification of some of the generated hydrates.

[0015] Furthermore, in the above technical solution, each stage of the Venturi mixer throat section is provided with an air inlet, and the low-temperature high-pressure mixed gas can be introduced into each stage of the Venturi mixer respectively.

[0016] Furthermore, in the above technical solution, the multi-level hybrid units can be connected in series.

[0017] Furthermore, in the above technical solution, the mixed gas can be CO2 and CH4; the working fluid can be an aqueous solution of TBAB.

[0018] According to a second aspect of the present invention, the present invention provides a hydrate-based continuous gas separation system, comprising a mixing unit as described above, and further comprising: an air inlet unit, which supplies gas through a high-pressure gas cylinder, wherein the cooled mixed gas enters a buffer gas cylinder through parallel air inlet pipelines, and after obtaining a preset pressure of mixed gas in the buffer gas cylinder, it is introduced into each stage of the Venturi mixer in the mixing unit; a liquid inlet unit, which pumps the cooled working liquid into the first stage Venturi mixer; and a gas-liquid separation unit, which receives gas B and a hydrate slurry containing gas A from the last stage tubular reactor of the mixing unit and performs gas-liquid separation; the hydrate slurry after gas-liquid separation is decomposed into gas A and a liquid phase, and the decomposed liquid phase is injected into the liquid inlet unit as a circulating working liquid.

[0019] Furthermore, in the above technical solution, the intake unit may include: a booster subunit, which is connected in parallel in the intake pipeline and adjusts the pressure of the mixed gas through a gas compressor according to the pressure required to form hydrates; and a back pressure subunit, which releases pressure when the pressure of the mixed gas in the intake pipeline exceeds the alarm value.

[0020] Furthermore, in the above technical solution, the gas-liquid separation unit may include: a gas-liquid separator, which receives gas B and hydrate slurry from the last-stage tubular reactor and separates gas B for recovery; a hydrate dissolution subunit, which receives hydrate slurry from the gas-liquid separator and heats and depressurizes the hydrate to dissolve it into gas A and working fluid; gas A is separated and recovered.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) This invention uses a multi-stage mixing unit to connect the Venturi mixer and the tubular reactor in each stage of the mixing unit in series. In the Venturi mixer, the gas-liquid mixing is more thorough, and the two mixed flows collide at high speed and vertically, reaching an extremely high relative velocity between the phases at the moment of impact, thereby greatly enhancing the interphase transfer.

[0023] 2) The multi-layered baffles with hill-shaped protrusions in the tubular reactor of this invention can fully contact gas A with the working liquid, and the generated vortex increases the reaction time in the tubular reactor, promotes mass transfer, and achieves better separation effect; the staggered protrusions can play a guiding role and avoid slurry blockage.

[0024] 3) In this invention, the hydrate crystals that have been generated collide with the staggered partition protrusions and become small particles. These small particles can act as inducing nuclei for hydrates, increasing the number of nucleation sites and increasing the contact area between the hydrate and the gas, thereby further promoting the formation of hydrates.

[0025] 4) The tubular reactor of the present invention has a long gas-liquid contact residence time and a fast gas-liquid interface renewal rate, which is more conducive to the continuous, efficient and rapid generation of hydrates.

[0026] 5) By introducing mixed gas into each stage of the Venturi mixer, the present invention can achieve continuous gas hydration separation, effectively making up for the shortcomings of simple hydrates in separating low-concentration gases and requiring additional pressure to achieve complete separation when the concentration of gas A is low. This can effectively save costs and reduce energy consumption.

[0027] 6) The system of the present invention improves the hydrate generation efficiency by adopting a multi-stage continuous generation process. Multi-stage hydrate generation can increase the pressure to the same level in each mixing unit, avoiding the problem of reserving pressure drop loss in the process of multi-stage hydrate generation. The system includes the entire process of hydrate generation, separation and dissolution, realizing continuous gas separation by hydrate method.

[0028] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the connection of the continuous gas separation system of the hydrate method of the present invention.

[0030] Figure 2 This is a schematic diagram of the structure of the mixing unit Chinese Turi mixer of the present invention.

[0031] Figure 3 This is a schematic diagram of the internal structure of the tubular reactor in the mixing unit of the present invention (the arrows in the diagram indicate the flow direction of the gas-liquid mixture).

[0032] Explanation of key figure labels:

[0033] 1-High-pressure gas cylinder; 2-First shut-off valve; 3-Second shut-off valve; 4-Gas compressor; 5-Third shut-off valve; 6-Buffer gas cylinder; 7-Fourth shut-off valve; 8-Fifth shut-off valve; 9-Sixth shut-off valve; 10-Seventh shut-off valve; 11-First-stage tubular reactor; 111-First baffle; 112-Second baffle; 113-Hill-shaped protrusion; 12-Second-stage tubular reactor; 13-Nth-stage tubular reactor; 14-Storage tank; 15-Eighth shut-off valve; 16-Circulation pump; 17-Ninth shut-off valve; 18-Venturi mixer; 181-Working fluid precooling line; 182-Inlet section; 183-Reduction section; 184-Throat section; 185-Outlet stabilization section; 186-Air inlet pipe; 19-Gas-liquid separator; 20-Tenth shut-off valve; 21-Hydrate dissolution subunit; 22-Eleventh shut-off valve; 23-Twelfth shut-off valve; 24-Thirteenth shut-off valve; 25-Back pressure valve; 26-Fourteenth shut-off valve; 27-Discharge hose; 28-Dosing tank; 29-Plunger pump; 30-High and low temperature bath. Detailed Implementation

[0034] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0035] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0036] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “up,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0037] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0038] This invention discloses a continuous gas separation system using hydrates, used to separate A / B gases in a gas mixture. Different gases form hydrates under different conditions. When gas mixture A / B forms hydrates, component A, which readily forms hydrates, accumulates in the hydrate phase, thus achieving gas separation. The system employs a multi-stage separation process through multiple series-connected mixing units (including a Venturi mixer and a tubular reactor), achieving continuous separation of the mixed gas and maintaining the system's reaction motive force. This effectively improves the separation efficiency compared to single-stage separation, saves energy, and enables highly efficient continuous gas separation. Example 1

[0039] This embodiment provides a mixing unit applied in a continuous gas separation process using hydrates. The mixing unit is multi-stage and can be connected in series. Figure 1 , 2 As shown, each mixing unit in this embodiment includes a Venturi mixer 18 and a tubular reactor. The Venturi mixer 18 is a device for efficient mixing of liquids and gases. It is connected upstream to a working fluid pre-cooling pipeline 181 and downstream to a hydration reaction pipeline, both connected via flanges. The Venturi mixer 18 can be divided into an inlet section 182, a narrowing section 183, a throat section 184, and an outlet stabilization section 185. The throat section 184 has a vent connecting to an inlet pipe 186 for introducing a mixture of gases A and B. The inlet section 182 of the Venturi mixer 18 receives the cooled working fluid, and the throat section 184 receives a preset low-temperature, high-pressure mixed gas. The mixed gas and working fluid undergo vertical collision in the throat section to enhance the interphase transfer between gas and liquid. After mixing, the gas and liquid flow out from the outlet stabilization section 185. The mixed gas can be CO2 and CH4, and the working fluid can be a TBAB aqueous solution (i.e., tetrabutylammonium bromide aqueous solution). Since partial hydrates are directly formed after the gas and liquid are mixed in each stage of the Venturi mixer 18, and the hydrate slurry may solidify, and due to the narrowing section and throat section structure of the Venturi mixer 18 itself, blockage is very likely to occur. Therefore, this embodiment has a dosing port in the inlet section 182 of the Venturi mixer 18, and the polymerization inhibitor in the dosing tank 28 is pumped into the mixer by the plunger pump 29 to avoid solidification of the generated partial hydrates. Furthermore, each stage of the Venturi mixer throat section 184 is provided with an air inlet, and the low-temperature high-pressure mixed gas can be introduced into each stage of the Venturi mixer 18, which can effectively ensure timely replenishment of the mixed gas, that is, to replenish the mixed gas lost due to the formation of hydrates. Using the Venturi gas-liquid mixing of this embodiment, the high-speed injected mixed gas impacts the high-speed working fluid from the narrowing section 183 in a vertical direction, which can produce an atomization effect on the working fluid, resulting in better gas-liquid mixing effect.

[0040] Further as Figure 1 , 3As shown, the tubular reactor receives a gas-liquid mixture (at which point a partial hydrate of gas A has already formed) from the Venturi mixer 18 for hydrate formation. The front end of the first-stage tubular reactor 11 is connected to the Venturi mixer 18 of its own stage, and the rear end is connected to the Venturi mixer 18 of the next stage. The front end of the second-stage tubular reactor 12 is connected to the Venturi mixer 18 of its own stage, and the rear end is connected to the Venturi mixer 18 of the next stage, and so on when the mixing unit is set to N stages (i.e., N-stage tubular reactors). The tubular reactors are designed to be detachable, allowing for free replacement between different pipe diameters. Preferably, but not limitingly, the straight pipes are designed to withstand a pressure of 15 MPa, operate at a temperature of -20 to 90°C, and are made of 316 stainless steel. Each stage of the tubular reactor has evenly spaced hill-shaped protrusions 113. As the gas-liquid mixture flows through the hill-shaped protrusions 113, turbulence is created, further mixing and reacting the gas and working liquid to achieve hydrate formation. Preferably, but not limitingly, the tubular reactor 11 is designed as a straight tube structure, and the reactor is provided with multiple layers of baffles extending axially. Figure 3 (Two layers are shown in the image). The hill-like protrusions 113 can be arranged in multiple rows along the axial direction, with adjacent rows of protrusions staggered. Further, when the number of partitions is two layers (i.e.,...) Figure 3 The first partition 111 and the second partition 112 are respectively arranged at 1 / 3 and 2 / 3 of the diameter from the bottom of the straight pipe.

[0041] The inventors discovered that by employing a layered arrangement of baffles and hill-shaped protrusions 113, the gas-liquid mixture, after passing through the Venturi mixer 18, flows to the inlet of the first-stage tubular reactor 11. Under the action of the baffles, it is divided into three layers, expanding the area for turbulence generation. Each baffle layer preferably has three rows of hill-shaped protrusions 113, with adjacent protrusions staggered, which serves as a guide, preventing the accumulation and blockage of hydrate slurry formed in the tubular reactor. After the fluid flows into each layer, it encounters a pressure gradient difference perpendicular to the fluid flow direction upon encountering the protrusions, resulting in two-directional fluid flow and generating vortices. Figure 3 As indicated by the arrow, eddies are a type of accompanying flow occurring in the mainstream direction. The presence of protrusions increases the velocity variation of the fluid, causing turbulent disturbances. Experiments have verified that this increases the energy loss caused by resistance during fluid movement, improves the mass and heat transfer performance of the fluid, enhances further mixing, and promotes hydrate formation. In this embodiment, the secondary tubular reactor 12 up to the Nth-stage tubular reactor 13 can all adopt the same arrangement of baffles and protrusions as in the primary tubular reactor 11.

[0042] Furthermore, such as Figure 1As shown, due to the high temperature requirements of the hydration reaction, in order to maintain the necessary constant temperature in the first-stage tubular reactor 11, the second-stage tubular reactor 12, and the Nth-stage tubular reactor 13, this embodiment provides a high-low temperature bath 30 for temperature control outside the tubular reactors. The operating temperature of this bath is designed to be -20~90℃, and it has functions such as overheat protection and overload protection. Furthermore, for easy observation, a transparent viewing window can be provided on the straight tube of the tubular reactor, which can be made of high-strength, pressure-resistant sapphire material with a pressure resistance of 20MPa, for observing the flow of the gas-liquid mixture and the formation of hydrates in the tubular reactor.

[0043] This embodiment utilizes a multi-stage mixing unit, connecting a Venturi mixer and a tubular reactor in series at each stage. The Venturi mixer ensures more thorough gas-liquid mixing, with the two mixed streams colliding at high speeds and perpendicularly, achieving extremely high relative velocities at the moment of impact, thus significantly enhancing interphase transfer. In the tubular reactor, multiple layers of baffles with hill-like protrusions allow for full contact between gas A and the working liquid. The resulting vortices increase the reaction time within the tubular reactor, promoting mass transfer and achieving better separation. The staggered protrusions also act as guides, preventing slurry blockage. Simultaneously, the formed hydrate crystals collide with the staggered protrusions, breaking into smaller particles. These smaller particles act as induced nuclei for hydrate formation, increasing the number of nucleation sites and expanding the contact area between the hydrate and gas, further promoting hydrate formation. In the tubular reactor of this embodiment, the gas-liquid contact residence time is long and the gas-liquid interface renewal rate is fast, which is more conducive to the continuous, efficient and rapid generation of hydrates. By introducing mixed gas into each stage of the Venturi mixer, continuous gas hydration separation can be achieved, which effectively makes up for the shortcomings of simple hydrates having low separation efficiency for low-concentration gases and the need for additional pressure to achieve complete separation when the concentration of gas A is low, thus saving costs and reducing energy consumption. Example 2

[0044] like Figure 1As shown, this embodiment provides a continuous gas separation system for hydrate formation, including the mixing unit described in Embodiment 1 above, as well as an air intake unit, a liquid intake unit, and a gas-liquid separation unit. The air intake unit supplies gas through a high-pressure gas cylinder 1. Since the mixed gas needs to undergo a hydration reaction at a low temperature, cooling of the mixed gas can be performed at the front end of the high-pressure gas cylinder or in the air intake pipeline at the rear end of the high-pressure gas cylinder. The cooled mixed gas enters a buffer gas cylinder 6 through parallel air intake pipelines. After obtaining a preset pressure (i.e., the high-pressure environment required for the hydration reaction) in the buffer gas cylinder 6, the mixed gas is then introduced into each stage of the Venturi mixer in the mixing unit. Specifically, the air intake unit includes a high-pressure gas cylinder 1, a first shut-off valve 2, a second shut-off valve 3, a gas compressor 4, a third shut-off valve 5, and a buffer gas cylinder 6. The gas compressor 4 and the second shut-off valve 3 serve as a pressurization subunit, connected in parallel to the air intake pipeline where the third shut-off valve 5 is located. The pressure of the mixed gas is adjusted by the gas compressor 4 according to the pressure required for hydrate formation. The buffer gas cylinder 6 supplies gas to the Venturi mixers 18 of each mixing unit via the fourth shut-off valve 7, the fifth shut-off valve 8, the sixth shut-off valve 9, and the seventh shut-off valve 10. The intake unit also includes a back pressure subunit, with a thirteenth shut-off valve 24 and a back pressure valve 25 installed on the pipeline between the buffer gas cylinder 6 and the mixing unit. The back pressure valve 25 allows for pressure relief when the mixed gas pressure in the intake pipeline exceeds an alarm value. An emergency discharge hose 27, controlled by a fourteenth shut-off valve 26, can also be installed.

[0045] Further as Figure 1 As shown, the liquid inlet unit pumps the cooled working fluid into the first-stage Venturi mixer of the mixing unit. Specifically, the liquid inlet unit includes a reservoir 14, an eighth shut-off valve 15, a circulation pump 16, and a ninth shut-off valve 17. The reservoir 14 is used to provide the cooled cryogenic working fluid.

[0046] Further as Figure 1 As shown, the gas-liquid separation unit includes a gas-liquid separator 19 and a tenth shut-off valve 20. The gas-liquid separator 19 receives gas B and a hydrate slurry containing gas A from the last-stage tubular reactor of the mixing unit and performs gas-liquid separation. The separated gas B is recycled. The gas-liquid separation unit also includes a hydrate dissolution subunit 21. The hydrate dissolution subunit 21 receives the hydrate slurry from the gas-liquid separator and heats and depressurizes the hydrate, dissolving it into gas A and working fluid. Gas A is controlled by the eleventh shut-off valve 22 and separated for recycling. The decomposed liquid phase is injected into the storage tank 14 of the inlet unit as a circulating working fluid.

[0047] The following is a specific example illustrating the continuous gas separation process of the hydrate method of the present invention:

[0048] like Figure 1As shown, the CO2 and CH4 mixture in high-pressure cylinder 1 is directly introduced into buffer cylinder 6 under high pressure. If the pressure cannot meet the separation requirements of the hydrate method, it is pressurized by gas compressor 4, and then enters the Venturi mixers 18 of each stage through the fifth shut-off valve 8, the sixth shut-off valve 9, and the seventh shut-off valve 10. The TBAB aqueous solution in storage tank 14 enters the first-stage Venturi mixer 18 through circulation pump 16 and the ninth shut-off valve 17. The TBAB aqueous solution is fully mixed with the CO2 and CH4 mixture in the throat section. The water bath temperature of the first-stage tubular reactor 11 is set to 8-10℃. The mixed fluid flows into the first stage. In the tubular reactor 11, the fluid is divided into three layers. After sufficient gas-liquid contact through the hill-shaped protrusions on the baffle, it enters the second-stage Venturi mixer 18. Gas is introduced through the sixth shut-off valve 9 to replenish the mixed gas lost due to the formation of hydrates, and the above process is repeated. After three thorough gas-liquid mixing reactions, the hydrate slurry enters the gas-liquid separator 19. The separated CH4 gas is discharged and collected through the tenth shut-off valve 20. The CO2 hydrate slurry enters the hydrate dissolution subunit 21. The dissolved CO2 is discharged and collected through the eleventh shut-off valve 22. The dissolved TBAB solution is returned to the storage tank 14 through the twelfth shut-off valve 23 for the next gas separation cycle.

[0049] The system in this embodiment not only has the advantages of gas-liquid mixing and contact reaction over the prior art as described in Embodiment 1, but also improves the hydrate generation efficiency by adopting a multi-stage continuous generation process. Multi-stage hydrate generation can increase the pressure to the same level in each mixing unit, avoiding the problem of reserving pressure drop loss in the process of multi-stage hydrate generation. The system includes the entire process of hydrate generation, separation and dissolution, realizing continuous gas separation by hydrate method.

[0050] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A mixing unit, characterized by In a continuous gas separation process using hydrates, the mixing unit is configured in multiple stages, with each stage connected in series. The mixing unit includes: The Venturi mixer receives cooled working fluid at its inlet section and a preset low-temperature, high-pressure mixed gas at its throat section. The mixed gas and working fluid collide vertically at the throat section to enhance the interphase transfer of gas and liquid. After mixing, the gas and liquid flow out from the outlet stabilization section. A tubular reactor has a straight tube structure and multiple axially extending baffles. The baffles have hill-shaped protrusions arranged in multiple rows along the axial direction, with adjacent rows of protrusions staggered. The tubular reactor receives a gas-liquid mixture from the Venturi mixer. As the gas-liquid mixture flows through the protrusions, it creates turbulent disturbances, allowing the mixed gas and working liquid to further mix, contact, and react, thereby generating hydrates.

2. The hybrid unit according to claim 1, characterized in that, The number of partitions is two layers, and the two layers of partitions are respectively arranged at 1 / 3 diameter and 2 / 3 diameter from the bottom of the straight pipe.

3. The hybrid unit according to claim 1, characterized in that, The tubular reactor is equipped with a temperature control bath outside, and the operating temperature of the bath is -20~90℃.

4. The hybrid unit according to claim 1, characterized in that, The tubular reactor has a transparent viewing window on its straight tube, which is pressure resistant to 20 MPa, for observing the flow of the gas-liquid mixture and the formation of hydrates.

5. The hybrid unit according to claim 1, characterized in that, The inlet section of the Venturi mixer is provided with a dosing port for pumping an inhibitor into the mixer to prevent the solidification of some of the generated hydrates.

6. The hybrid unit according to claim 1, characterized in that, Each stage of the Venturi mixer has an air inlet in its throat section, and the low-temperature, high-pressure mixed gas is introduced into each stage of the Venturi mixer.

7. The hybrid unit according to claim 1, characterized in that, The mixed gas is CO2 and CH4; the working fluid is an aqueous solution of TBAB.

8. A continuous gas separation system using hydrates, characterized in that, Including the hybrid unit as described in any one of claims 1 to 7, further comprising: The air intake unit is supplied with air through a high-pressure gas cylinder. The cooled mixed air enters the buffer gas cylinder through parallel air intake pipes. After obtaining the preset pressure in the buffer gas cylinder, the mixed air is introduced into each stage of the Venturi mixer in the mixing unit. The liquid inlet unit pumps the cooled working fluid to the first-stage Venturi mixer; The gas-liquid separation unit receives gas B and hydrate slurry containing gas A from the last stage tubular reactor of the mixing unit and performs gas-liquid separation; the hydrate slurry after gas-liquid separation is decomposed into gas A and liquid phase, and the decomposed liquid phase is injected into the liquid inlet unit as circulating working fluid.

9. The hydrate-based continuous gas separation system according to claim 8, characterized in that, The intake unit includes: The booster unit, which is connected in parallel in the intake pipe, adjusts the pressure of the mixture via a gas compressor according to the pressure required to form hydrates. The back pressure subunit releases pressure when the air-fuel mixture pressure in the intake manifold exceeds an alarm value.

10. The hydrate-based continuous gas separation system according to claim 8, characterized in that, The gas-liquid separation unit includes: A gas-liquid separator that receives gas B and hydrate slurry from the last-stage tubular reactor and separates the gas B for recovery; The hydrate dissolution subunit receives the hydrate slurry from the gas-liquid separator and heats and depressurizes the hydrate to dissolve it into gas A and the working fluid; gas A is separated and recycled.

Images