A gas separator and separation method

Abstract

The present application relates to the technical field of gas separation, and specifically provides a gas separator and a separation method, the separator comprising a cylinder body, the cylinder body having a feed channel, the feed channel comprising a first pipe body, a second pipe body and a third pipe body, the first pipe body having a first channel and a second channel therein, the second pipe body having a third channel therein, the third pipe body having a fourth channel therein, the fourth channel extending into the second pipe body and being connected with the third channel in a smooth transition, the axis of the first channel being located in a radial plane of the cylinder body, the axes of the second channel, the third channel and the fourth channel all being located in a first plane, the first plane being arranged in an inclined downward manner relative to the radial plane of the cylinder body and having an included angle α ≤ 10°, the second channel axis being perpendicular to the first channel axis, the third channel axis having an included angle with the second channel axis, and the fourth channel axis having an included angle with the third channel axis. The risk of wall sticking is effectively reduced, and the separation efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of gas separation technology, and in particular to a gas separator and separation method. Background Technology

[0002] The high-pressure circulating gas separator, a key separation device in the tubular polyethylene production process, serves as a crucial link between the high-pressure separator and subsequent separation processes. It separates liquid and solid impurities or gases of different components from the process gas under high-pressure conditions. Since the polymerization reaction temperature of tubular polyethylene is approximately 200–300℃ and the pressure is 200–350 MPa, the reaction product is a polyethylene melt under high temperature and pressure, with a viscosity much higher than that of polyethylene at room temperature and pressure. When the melt enters the separator with the circulating gas, the flow rate decreases, the temperature drops slightly, and the viscosity further increases, making it more likely to adhere to the surfaces of the separator walls and other components, forming a wall-adhesive layer. This wall-adhesive phenomenon not only leads to a decrease in separation efficiency but can also cause equipment blockage, increased operating energy consumption, and other problems, seriously affecting the continuous and stable operation of the plant. Summary of the Invention

[0003] The purpose of this invention is to solve the problem that in the prior art, when separators are used for polyethylene melt under high temperature and high pressure, there is obvious wall adhesion, which leads to a decrease in separation efficiency and may also cause equipment blockage and increased operating energy consumption. The invention provides a gas separator and separation method.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, a gas separator is provided, comprising a cylindrical body, the top of which has an upward-facing gas phase outlet, and a feed channel on the side of which is a feed channel comprising a first tube, a second tube, and a third tube connected in sequence. The first tube has a first channel and a second channel, the second tube has a third channel, and the third tube has a fourth channel. The fourth channel extends into the second tube and smoothly transitions to the third channel. The axis of the first channel is located in the radial plane of the cylindrical body, and the axes of the second, third, and fourth channels are all located in a first plane. The first plane is inclined downward relative to the radial plane of the cylindrical body at an angle α ≤ 10°. The axis of the second channel is perpendicular to the axis of the first channel and smoothly transitions to the first channel. The axis of the third channel has an angle with the axis of the second channel and faces away from the cylindrical body, and the axis of the fourth channel has an angle with the axis of the third channel and faces away from the cylindrical body.

[0006] The feed channel draws air from the side of the cylinder, meaning the first channel is arranged radially along the cylinder. Combined with the optimized design of multi-section variable flow channels and internal arc transitions, tangential feeding is achieved, reducing material flow resistance and turbulence effects, and decreasing the probability of material adhesion to the separator wall. This fundamentally solves the problem of wall adhesion. It can also pre-accelerate and pre-swirl the feed fluid, causing the material to form a stable strong swirling state after entering the separator. Under the combined action of centrifugal force and gravity, it can effectively separate tiny droplets that are difficult to remove with conventional structures, preventing the separated liquid from flowing back into the feed channel, reducing material accumulation on the wall, further reducing the risk of wall adhesion, and significantly improving separation efficiency compared to traditional feed structures.

[0007] Optionally, the third tube is a tapered tube, with the outlet diameter larger than the inlet diameter. The tapered tube's expansion structure gradually reduces the fluid velocity as it enters the cylinder, preventing sudden velocity changes that could cause direct impact on the cylinder wall, further reducing material adhesion and accumulation. Simultaneously, it promotes a more stable flow field during the swirling process, enhancing separation stability.

[0008] Optionally, the cone angle θ of the tapered tube is 12-16°. This cone angle range can ensure the expansion and speed reduction effect while avoiding the generation of vortices caused by abrupt changes in the flow channel due to an excessively large cone angle, thus ensuring smooth fluid flow.

[0009] Optionally, the angle γ=θ between the axis of the fourth channel and the interface between the third channel and the second channel.

[0010] Optionally, the third channel has a diffusion structure facing the opening of the third tube, and the cone angle β of the diffusion structure is θ.

[0011] The aforementioned angular arrangement allows multiple channels to form a continuous and smooth turning direction, avoiding excessive flow channel turning angles that could cause fluid impact and adhesion to the walls, thus ensuring the formation of the pre-swirling flow.

[0012] Optionally, the angle α between the first plane and the radial plane of the cylinder is 5-8°.

[0013] This tilt angle range can effectively balance the effects of centrifugal separation and gravity drainage, ensuring both the intensity of the swirling flow and guiding the separated liquid phase to flow downwards along the wall, preventing the liquid phase from converging upwards and affecting the gas phase outlet.

[0014] Optionally, the feed channel is located at the upper part of the cylinder, and the outlet of the third tube extends beyond the centerline of the cylinder. The feed outlet extends beyond the centerline of the cylinder into the opposite region, allowing the pre-swirled feed fluid to directly rotate and flow along the cylinder wall, which is beneficial for forming a stable, strong swirling flow.

[0015] Optionally, the outer side of the cylinder is provided with a heat tracing coil, and the outer wall of the end cap at the bottom of the cylinder is provided with a jacket. The heat tracing coil and the jacket work together to heat and insulate the cylinder, maintain a stable material temperature, avoid adhesion to the wall caused by increased viscosity, and further reduce the risk of wall adhesion.

[0016] Optionally, the bottom of the cylinder has a wax discharge port to facilitate the periodic discharge of separated impurity melt, ensuring long-term stable operation of the equipment.

[0017] Secondly, the present invention also provides a gas separation method applied to the gas separator described in any of the above claims. A polyethylene gas-liquid mixture is introduced into the cylinder through a feed channel for gas-liquid separation. The gas phase density of the mixture is 240-270 kg / m³, and the liquid phase density is 950-1050 kg / m³. The pressure inside the cylinder is 30-37.8 MPa, and the temperature is 170-220°C. Using the gas separator of the present invention with corresponding process parameters can effectively adapt to the separation requirements of the tubular polyethylene production process, reduce wall adhesion and blockage, and improve separation efficiency.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The gas separator described in this invention introduces gas from the side of the cylinder through the feed channel. The feed inlet and multi-section variable-direction flow channels are optimized and designed with an internal arc transition to reduce resistance and turbulence during material flow, thereby reducing the possibility of material adhesion to the separator wall and fundamentally solving the problem of material sticking to the wall. Simultaneously, this design pre-accelerates and pre-swirls the feed fluid, ensuring a stable and strong swirling state after the material enters the separator. Under the combined action of centrifugal force and gravity, it can effectively separate tiny droplets that are difficult to remove with conventional structures, preventing the separated liquid phase from flowing back into the feed channel, reducing material accumulation on the wall, and further reducing the risk of wall adhesion. Compared with traditional feed structures, the separation efficiency is significantly improved.

[0019] 2. A gas separation method is adopted. By using the gas separator of the present invention and matching the corresponding process parameters, the separation requirements of the tubular polyethylene production process can be effectively adapted, reducing wall adhesion and clogging, and improving separation efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic elevation view of a gas separator; Figure 2 This is an elevation view of the feeding channel; Figure 3 This is a plan view of the feeding channel; Figure 4 This is a planar sectional view of the feed channel; Figure 5 This is a front view of the feeding channel.

[0021] Reference numerals: 1-Cylinder, 11-Gas phase outlet, 12-Jacket, 13-Cylinder flange, 2-Feed channel, 21-First pipe body, 22-Second pipe body, 23-Third pipe body, 24-Support plate, 3-Heating coil, 4-Wax discharge port, 5-Clamping clamp. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings.

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of the present invention is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0025] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but that it can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0026] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0027] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as 2, 3, 4, 5, 6, 7, 8, or 9, and can even exceed nine.

[0028] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0029] Example 1 like Figures 1-5 As shown, the gas separator used in this invention includes a cylindrical body 1. The top of the cylindrical body 1 has an upward-facing gas phase outlet 11. The side of the cylindrical body 1 has a feed channel 2. The feed channel 2 includes a first tube 21, a second tube 22, and a third tube 23 connected in sequence. The first tube 21 has a first channel and a second channel. The second tube 22 has a third channel. The third tube 23 has a fourth channel. The fourth channel extends into the second tube 22 and smoothly transitions to the third channel. The axis of the first channel is located in the radial plane of the cylindrical body 1. The axes of the second, third, and fourth channels are all located in a first plane. The first plane is inclined downward relative to the radial plane of the cylindrical body 1 with an angle α ≤ 10°. The axis of the second channel is perpendicular to the axis of the first channel. The second channel smoothly transitions to the first channel. The axis of the third channel has an angle with the axis of the second channel and faces away from the cylindrical body 1. The axis of the fourth channel has an angle with the axis of the third channel and faces away from the cylindrical body 1.

[0030] Specifically, such as Figure 1 As shown, the inner diameter of cylinder 1 can be DN2000~2500mm, the wall thickness can be 195-235mm, and the tangent length is 5000-7000mm. Figure 1The distance between the upper and lower dotted lines), the top is connected to the flat cover head, the flat cover head is provided with a gas phase outlet 11, the upper part of the inner cavity of the cylinder 1 is provided with a cylinder flange 13, the feed channel 2 is connected through the cylinder flange 13, the outer wall of the cylinder 1 is surrounded by a heat tracing coil 3, the bottom of the cylinder 1 is connected to the lower spherical head, the outer wall of the lower spherical head is provided with a jacket 12, the bottom is provided with a wax discharge port 4, the flange of the gas phase outlet 11 and the flat cover head adopt a C-shaped ring conical surface sealing structure, which achieves reliable sealing under high pressure conditions through the slight elastic deformation of the C-shaped ring conical surface, with excellent sealing performance and strong stability.

[0031] The heat tracing coils 3 are evenly distributed along the circumference of the outer ring of the cylinder 1 at arc lengths of 100mm-120mm. The coils can be divided into two halves, which can be detachably connected by clamps 5, facilitating installation, inspection, and maintenance. When the heat tracing coils 3 are separated, high-pressure steam with a working temperature of 243-275℃ can be introduced. Through continuous heating and heat preservation, the material temperature can be effectively maintained, avoiding the problem of material sticking to the wall caused by increased viscosity due to temperature drop.

[0032] like Figure 1-5 As shown, the feed channel 2 includes a first pipe body 21, a second pipe body 22, and a third pipe body 23 connected in sequence. The first pipe body 21 has an annular disc-shaped flange, coaxially arranged with the cylinder flange 13, so that the first channel is arranged radially along the cylinder 1. It is sealed by bolt connection, and a circular through hole is opened inside the flange to ensure smooth material flow. The second pipe body 22 is a cylindrical hollow structure with an included angle between the inlet and outlet ends. The inner hole axis is semi-Y-shaped, and the connection within the hole uses a rounded transition, which can effectively reduce material flow resistance and avoid the risk of wall adhesion caused by local turbulence. The third pipe body 23 is supported by a support plate 24 connected to the cylinder 1. The third pipe body 23 is a tapered pipe, and the outlet end size of the tapered pipe is larger than the inlet end size, such as... Figure 4 As shown, the cone angle θ of the conical tube can be 12-16°. The cone angle design can guide the material to form a stable tangential flow state, improving the centrifugal separation effect. In this embodiment, it is set to 14°. The angle γ=θ between the axis of the fourth channel and the interface of the third and second channels, i.e., γ=14°, is the angle between the axis of the fourth channel and the interface. The side of the third channel facing the opening of the third tube body 23 is set as a diffusion structure, see [reference]. Figures 3-4 The cone angle of the diffuser structure is β=θ, that is, β=14°, which makes the inner side of the transition between the third channel and the fourth channel have an enlarged structure. Combined with the various angles, the flow channels are smoothly connected and the air intake is smooth. The corners of the diffuser structure are still smooth transitions.

[0033] The first, second, third, and fourth channels all have smooth transitions. The first tube 21 has a first channel and a second channel with mutually perpendicular axes. See [reference needed]. Figures 3-4In this embodiment, the diameter of the first and second channels in the first tube 21 can be set to 210mm. The axis of the first channel is located in the radial plane of the cylinder 1. The axes of the second, third, and fourth channels are all located in the first plane. The first plane is inclined downward relative to the radial plane of the cylinder 1 with an included angle α ≤ 10°, and can be selected in the range of 3-10°, 5-10°, 3-8°, 5-8°, etc. This embodiment uses 5°. Figure 1 and Figure 5 As shown, the tilt design further enhances the centrifugal motion tendency of the material after entering the shell, and improves the separation efficiency in conjunction with the effect of gravity.

[0034] The third channel serves as a transition channel between the second and fourth channels. It involves a first turn within the first tube 21, followed by a second turn via the second tube 22. The airflow gradually adjusts its direction, smoothly transitioning to a tangential spiral within the cylinder. Compared to a single turn (direct tangential intake), this structure offers the following advantages: 1. Two progressive turns allow for gradual adjustment of the airflow direction, smoothly transitioning to a tangential spiral within the cylinder. This results in uniform airflow angular velocity, a stable overall flow field within the cylinder, and a 15%–30% reduction in pressure drop compared to a direct inlet. It also reduces vibration and noise during overall machine operation. 2. Two-stage bends buffer kinetic energy: The airflow first turns in the first tube 21 to dissipate some of the impact momentum, then undergoes a second guide via the second tube 22. Upon entering the cylinder, the fluid direction closely follows the cylinder wall's spiral direction, rotating almost parallel to the wall. This significantly reduces the impact force of the vertical impact on the cylinder wall, substantially extending the service life of the cylinder and the inner wall weld overlay. This makes it suitable for high-pressure conditions containing impurities (particularly crucial in petrochemical EVA and hydrotreating scenarios).

[0035] The outlet of the third tube 23 crosses the centerline of the cylinder 1, such as... Figures 1-3 As shown, this ensures that the pre-swirling fluid can directly adhere to the cylinder wall to form a stable swirling flow.

[0036] The gas separator described in this invention introduces gas from the side of the cylinder through the feed channel. The feed inlet and multi-section variable-direction flow channels are optimized and designed with an internal arc transition to reduce resistance and turbulence during material flow, minimizing the possibility of material adhesion to the separator wall and fundamentally solving the problem of material sticking to the wall. Simultaneously, this design pre-accelerates and pre-swirls the feed fluid, creating a stable and strong swirling state after the material enters the separator. Under the combined action of centrifugal force and gravity, it can effectively separate tiny droplets that are difficult to remove with conventional structures, preventing the separated liquid phase from flowing back into the feed channel, reducing material accumulation on the wall, and further reducing the risk of wall adhesion. Compared to traditional feed structures, the separation efficiency is significantly improved.

[0037] This device is applicable to high-pressure processes that require gas recycling, such as polyethylene production, coal chemical industry, and hydrocracking. It can also be extended to gas-liquid-solid and gas-solid separation scenarios.

[0038] Example 2 A gas separation method employs a gas separator as described in Example 1. In practical application, this gas separator is used in the gas-liquid separation process of tubular polyethylene production. A polyethylene gas-liquid mixture is introduced into the cylinder 1 through the feed channel 2. The gas phase density of the mixture is controlled to be 250 kg / m³, and the liquid phase density is controlled to be 1000 kg / m³. The pressure inside the cylinder 1 is 35 MPa, and the temperature is 190°C. The above temperature and pressure are the working temperature and working pressure inside the cylinder 1. Steam is continuously introduced through the heating coil 3. The temperature and pressure of the steam are higher than the pressure and temperature inside the cylinder. For example, high-pressure steam with a working temperature of 243-275°C is introduced. The temperature is within the polymerization reaction temperature range of tubular polyethylene. The mixture enters the cylinder after pre-swirling through the multi-segment flow channel of the feed channel, forming a stable downward swirling flow. Under the action of centrifugal force and gravity, the denser polyethylene liquid phase is thrown towards the cylinder wall and flows downward along the wall to accumulate. The less dense gas phase rises in the center of the cylinder 1 and is discharged from the top gas phase outlet 11, thus completing the gas-liquid separation. Under these process conditions, the gas separator exhibits a much lower wall adhesion rate than traditional separators, resulting in a significant improvement in separation efficiency and effectively extending the continuous operation cycle of the unit.

[0039] A gas separation method is adopted, and the gas separator of the present invention is matched with the corresponding process parameters, which can effectively adapt to the separation requirements of the tubular polyethylene production process, reduce wall adhesion and blockage, and improve separation efficiency.

[0040] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A gas separator, characterized in that, The device includes a cylindrical body (1) with an upward-facing gas phase outlet (11) at the top. The cylindrical body (1) has a feed channel (2) on its side. The feed channel (2) includes a first tube (21), a second tube (22), and a third tube (23) connected in sequence. The first tube (21) has a first channel and a second channel, the second tube (22) has a third channel, and the third tube (23) has a fourth channel. The fourth channel extends into the second tube (22) and smoothly transitions into the third channel. The axis of the channel is located in the radial plane of the cylinder (1). The axes of the second channel, the third channel and the fourth channel are all located in the first plane. The first plane is inclined downward relative to the radial plane of the cylinder (1) and the included angle α ≤ 10°. The axis of the second channel is perpendicular to the axis of the first channel. The second channel and the first channel are smoothly connected. The axis of the third channel has an angle with the axis of the second channel and faces away from the cylinder (1). The axis of the fourth channel has an angle with the axis of the third channel and faces away from the cylinder (1).

2. A gas separator according to claim 1, characterized in that, The third tube (23) is a tapered tube, and the outlet end of the tapered tube is larger than the inlet end.

3. A gas separator according to claim 2, characterized in that, The cone angle θ of the tapered tube is 12-16°.

4. A gas separator according to claim 2, characterized in that, The angle γ = θ is the intersection of the axis of the fourth channel with the interface of the third and second channels.

5. A gas separator according to claim 4, characterized in that, The third channel has a diffusion structure facing the opening of the third tube (23), and the cone angle of the diffusion structure is β=θ.

6. A gas separator according to any one of claims 1-5, characterized in that, The angle α between the first plane and the radial plane of the cylinder (1) is 5-8°.

7. A gas separator according to claim 6, characterized in that, The feed channel (2) is located at the upper part of the cylinder (1), and the outlet of the third tube (23) extends beyond the centerline of the cylinder (1).

8. A gas separator according to claim 6, characterized in that, The outer side of the cylinder (1) has a heat tracing coil (3), and the outer wall of the end cap at the bottom of the cylinder (1) is provided with a jacket (12).

9. A gas separator according to claim 6, characterized in that, The bottom of the cylinder (1) has a wax discharge port (4).

10. A gas separation method, characterized in that, Applied to a gas separator as described in any one of claims 1-9, a polyethylene gas-liquid mixture is introduced into the cylinder (1) through the feed channel (2) for gas-liquid separation, wherein the gas phase density of the mixture is 240-270 kg / m³, the liquid phase density is 950-1050 kg / m³, and the pressure inside the cylinder (1) is 30-37.8 MPa and the temperature is 170-220℃.

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