CN116617771A - Be applied to low pressure separator on high pressure polyethylene device - Google Patents
Be applied to low pressure separator on high pressure polyethylene device Download PDFInfo
- Publication number
- CN116617771A CN116617771A CN202310578311.5A CN202310578311A CN116617771A CN 116617771 A CN116617771 A CN 116617771A CN 202310578311 A CN202310578311 A CN 202310578311A CN 116617771 A CN116617771 A CN 116617771A
- Authority
- CN
- China
- Prior art keywords
- cylinder body
- cylinder
- low
- gas
- outlet pipe
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- -1 polyethylene Polymers 0.000 title claims abstract description 23
- 239000004698 Polyethylene Substances 0.000 title claims abstract description 21
- 229920000573 polyethylene Polymers 0.000 title claims abstract description 21
- 239000007788 liquid Substances 0.000 claims abstract description 56
- 238000000926 separation method Methods 0.000 claims abstract description 47
- 239000000203 mixture Substances 0.000 claims abstract description 45
- 229920000642 polymer Polymers 0.000 claims abstract description 34
- 238000007789 sealing Methods 0.000 claims abstract description 25
- 239000000178 monomer Substances 0.000 claims abstract description 14
- 238000007599 discharging Methods 0.000 claims abstract description 12
- 238000003466 welding Methods 0.000 claims abstract description 5
- 230000005855 radiation Effects 0.000 claims description 10
- 230000003746 surface roughness Effects 0.000 claims description 3
- 229920000098 polyolefin Polymers 0.000 abstract description 6
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- 230000002035 prolonged effect Effects 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 58
- 238000000034 method Methods 0.000 description 12
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 10
- 239000005977 Ethylene Substances 0.000 description 10
- 239000000047 product Substances 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 4
- 229920001577 copolymer Polymers 0.000 description 4
- 230000005484 gravity Effects 0.000 description 4
- 239000012071 phase Substances 0.000 description 4
- 238000006116 polymerization reaction Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000000630 rising effect Effects 0.000 description 3
- 239000004743 Polypropylene Substances 0.000 description 2
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical group CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000007792 gaseous phase Substances 0.000 description 2
- 229920001684 low density polyethylene Polymers 0.000 description 2
- 239000004702 low-density polyethylene Substances 0.000 description 2
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000004062 sedimentation Methods 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 1
- WSSSPWUEQFSQQG-UHFFFAOYSA-N 4-methyl-1-pentene Chemical compound CC(C)CC=C WSSSPWUEQFSQQG-UHFFFAOYSA-N 0.000 description 1
- 229920000089 Cyclic olefin copolymer Polymers 0.000 description 1
- 125000005396 acrylic acid ester group Chemical group 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000012986 chain transfer agent Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 229920006226 ethylene-acrylic acid Polymers 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000003999 initiator Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 150000001451 organic peroxides Chemical class 0.000 description 1
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D45/00—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces
- B01D45/12—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by centrifugal forces
- B01D45/16—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by centrifugal forces generated by the winding course of the gas stream, the centrifugal forces being generated solely or partly by mechanical means, e.g. fixed swirl vanes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D45/00—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces
- B01D45/02—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by utilising gravity
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Cyclones (AREA)
Abstract
The invention discloses a low-pressure separation device applied to a high-pressure polyethylene device, and belongs to the technical field of polyolefin production. Comprising the following steps: the device comprises a barrel, a base, an upper sealing head, a mixture inlet pipe, a gas outlet pipe, a liquid outlet pipe and a liquid outlet pipe, wherein the base is arranged at the bottom of the barrel and is conical, the upper sealing head is arranged at the top of the barrel in a welding or flange connection mode, the mixture inlet pipe is used for introducing molten mixture into the barrel, the gas outlet pipe is arranged on the upper sealing head and is used for discharging unreacted polymer monomers and other light components, and the liquid outlet pipe is arranged at the bottom of the base and is used for discharging liquid polymer. According to the invention, the situation of gas-liquid entrainment phenomenon is reduced, namely, when the gas is separated at low pressure, the molten polymer is not easy to dope in the gas, so that the safe operation of a low-pressure system device is effectively ensured, and the service life of a compressor is prolonged.
Description
Technical Field
The invention relates to a low-pressure separation device applied to a high-pressure polyethylene device, and belongs to the technical field of polyolefin production.
Background
The polyolefin has rich raw materials, low cost, easy processing and forming and excellent comprehensive performance, so the polyolefin is a polymer material with very wide application. Of these, polyethylene and polypropylene are the most important. The main varieties of polyolefins are polyethylene and some copolymers based on ethylene, such as ethylene-vinyl acetate copolymers, copolymers of ethylene-acrylic acid or acrylic acid esters, and also polypropylene and some propylene copolymers, poly-1-butene, poly-4-methyl-1-pentene, cycloolefin polymers. Polyethylene is the simplest polymer in polyolefin, wherein low-density polyethylene has excellent low-temperature resistance, chemical stability, electrical insulation and processability, and is an indispensable material in agriculture, building industry, national defense and people's daily life. In tubular low density polyethylene processes, the single pass conversion of ethylene is typically only about 30%, and therefore it is necessary to separate the polymer from the bulk of unreacted ethylene monomer, copolymer monomer, chain transfer agent, impurities, by-products, and other light components.
Typically, the reaction product of the polymerization reaction is separated by reducing the pressure step by step using a 2-stage separator (i.e., a high pressure product separator and a low pressure separator). The molten mixture separated by the high-pressure product separator still contains 15 to 45 weight percent of dissolved monomers and other light components (such as oligomers, additives, solvents and the like), and the dissolved monomers and other light components are further separated from the polymer to extract the polymer with higher purity, and the polymer is separated by adopting a low-pressure separation device and then sent to an extrusion granulating system.
The low pressure separation device performs separation at a pressure of 0.1MPag to 0.7MPag and a temperature of 110℃to 320 ℃. Unreacted monomers and other light components are discharged from a gas outlet pipe of the low-pressure separation device in the form of gas, wax and oil are further separated out through a low-pressure circulation system, and olefin monomers are taken as raw materials and enter an auxiliary compressor together with fresh olefin. The polymer is discharged from the bottom outlet of the low pressure separator, discharged through an extruder and a granulator, and granulated.
Most polyethylene devices are easy to generate gas-liquid entrainment phenomenon when discharging the rest light components, namely, when the gas is separated at low pressure, the gas is easy to be doped with molten polymer, thereby influencing the safe operation of the low pressure system device and the service life of the compressor.
There is therefore a need to propose a new solution to this problem.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: the low-pressure separation device applied to the high-pressure polyethylene device solves the problem that most polyethylene devices in the prior art are easy to generate gas-liquid entrainment when discharging other light components, namely, when gas is separated at low pressure, the safe operation of the low-pressure system device and the service life of a compressor are affected.
The technical problems to be solved by the invention are realized by adopting the following technical scheme: a low pressure separator for use with a high pressure polyethylene device, comprising:
the cylinder body is provided with a cylinder body,
a base arranged at the bottom of the cylinder body and in a conical shape,
the upper sealing head is arranged at the top of the cylinder body in a welding or flange connection mode,
a mixture inlet pipe for introducing the molten mixture into the interior of the cylinder,
a gas outlet pipe which is arranged on the upper sealing head and is used for discharging unreacted polymer monomer and other light components,
a liquid outlet pipe arranged at the bottom of the base and used for discharging the polymer in liquid state,
wherein when the upper sealing head is welded on the top of the cylinder body, the mixture inlet pipe is arranged in a bypass rotary separation structure, namely is arranged at the tangential end of the outer wall of the cylinder body and is communicated with the cylinder body along the inclined upper side of the cylinder body,
when the upper end enclosure is connected to the top of the cylinder body through the flange, the mixture inlet pipe is communicated with the center end of the upper end enclosure along the vertical direction, and one end, extending into the cylinder body, of the mixture inlet pipe is provided with a conical pipe with gradually increased inner diameter along the direction away from the mixture inlet pipe.
The invention is further provided with: the ratio of the height of the low-pressure separation device to the inner diameter of the cylinder body is 0.5-12.
The invention is further provided with: the included angle of the inner wall of the base is 30-60 degrees.
The invention is further provided with: when the upper seal head is connected with the top of the cylinder body through a flange, the upper seal head is a standard elliptical seal head, the length of the conical tube is 15-55% of the height of the cylinder body, the included angle of the inner wall of the conical tube is 15-60 degrees,
in addition, at least 2 gas outlet pipes are arranged on the upper sealing head, the ratio of the distance between the central axis of each gas outlet pipe and the central axis of the cylinder to the inner diameter of the cylinder is 0.20-0.35, and the included angle between the central axis of each gas outlet pipe and the central axis of the cylinder is 0-35 degrees.
The invention is further provided with: when the upper sealing head is welded at the top of the cylinder body, the manhole is obliquely arranged on the outer wall of the cylinder body, the included angle between the manhole and the cylinder body in the horizontal direction is 5-20 degrees,
in addition, the gas outlet pipe is arranged at the center end of the upper sealing head, and the inner wall of the cylinder body is provided with a shock-proof plate.
The invention is further provided with: the base is provided with at least one radiation source for measuring the filling level height of the liquid component and a rod-shaped liquid level detector, and the rod-shaped liquid level detector records the liquid level height by measuring the attenuation of the radiation emitted by the radiation source after passing through the liquid in the cylinder.
The invention is further provided with: the surface roughness of the inner wall of the low pressure separator is 0.8 μm at the maximum.
The beneficial effects of the invention are as follows:
1. the upper seal head is preferably a standard elliptical seal head, and compared with a spherical crown seal head, the standard elliptical seal head has larger inner space, longer gas residence time, improved gas-liquid separation efficiency and better economy, thereby reducing the situation of gas-liquid entrainment phenomenon, namely, the gas is not easy to dope molten polymer during low-pressure separation of the gas, thereby effectively ensuring the safe operation of a low-pressure system device and prolonging the service life of a compressor;
2. the upper sealing head is convenient to detach in a flange connection mode between the upper sealing head and the cylinder body, so that the problem that the interior of the existing low-pressure separator is difficult to clean and overhaul is solved, and the structure is suitable for the low-pressure separator with a larger diameter; the upper end socket and the cylinder body are welded, and the manhole is arranged on the cylinder body, so that the upper end socket is not required to be disassembled, the cleaning and the overhauling of the inside of the low-pressure separator are convenient, the operation is convenient, the labor force is saved, and the device is suitable for the low-pressure separator with smaller diameter;
3. the mixture inlet pipe is arranged into a bypass type cyclone structure, the bypass type cyclone structure is a rotary motion introduced through the tangential direction of air flow, the centrifugal force has larger inertia to throw liquid drops to the inner wall surface of the low-pressure separator, and the centrifugal force borne by the liquid drops is far larger than gravity and inertia force, so that the separation efficiency is higher, and the structure is suitable for the operation condition that the flow speed of the mixture liquid drops entering the mixture inlet pipe is faster; when the mixture inlet pipe is vertically arranged on the upper seal head, the conical pipe is arranged at the bottom of the mixture inlet pipe, the working principle is that gas-liquid separation is realized through gravity sedimentation, in the descending process of the mixture liquid drops, the size of the polymer liquid drops is continuously increased, the gas phase entraining force is relatively small, and the gas-liquid separation is facilitated, so that the gas-liquid separation efficiency of the low-pressure separator is improved, and the economy is good.
4. Through the gas outlet pipe setting on the upper seal, for the vertical arrangement of gas outlet pipe on the barrel, the exit area space of retrieving gaseous phase component is bigger, gaseous in the exit area dwell time of low pressure separator gaseous phase component is longer, the gas-liquid separation effect is better, simultaneously because the gas outlet is arranged on the upper seal, can more effectively prevent that the polymer from blockking up in gas outlet pipe department, the gas circulation is more in line with the gas flow direction simultaneously, improve gas-liquid separation efficiency, save space again, the gas outlet is established and is stopped the blowing more conveniently on the upper seal, alleviate workman intensity of labour.
Drawings
FIG. 1 is a schematic diagram of an embodiment of the present invention;
FIG. 2 is a schematic diagram of a second embodiment of the present invention;
fig. 3 is a partial sectional view of the second embodiment.
In the figure: 1. a liquid outlet tube; 2. a base; 3. a radiation source; 4. a cylinder; 5. conical tube; 7. an upper end enclosure; 8. a gas outlet pipe; 9. a mixture inlet pipe; 10. a rod-like liquid level detector; 11. a manhole; 13. and a wash-out plate.
Detailed Description
The invention will be further described with reference to the following detailed drawings, in order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the invention easy to understand.
The low pressure separation apparatus provided by the invention is used for further separating the molten mixture (still containing 15 to 45% by weight of dissolved monomers and other light components) separated by the high pressure product separator.
For the convenience of understanding the present invention, the upstream process of the present invention will be described in a typical, but not limiting, manner, and the upstream polymerization process will be exemplified by a tubular process, which is a basic production process: ethylene and low-pressure circulating gas are compressed to 25-30 MPa by an auxiliary compressor, then compressed to the reaction pressure of 200-300 MPa by a main compressor, preheated to 150-180 ℃ and then sent to a tubular reactor, and an organic peroxide is used as an initiator for polymerization reaction. In this state, the density of ethylene is about 500kg/cm3 to 550kg/cm3, the flow rate of ethylene in the tube is 10m/s to 20m/s, and the residence time is 1 minute to 4 minutes. The heat generated by the polymerization reaction can lead the highest reaction temperature to reach 360 ℃, the mixture of unreacted monomers and polymers in the reactor enters a product cooler for cooling, and the process medium cooled by the product cooler enters a high-pressure separator for gas-liquid separation.
The cooled process medium is decelerated step by step in a pipeline and then enters a high-pressure product separator, gas-liquid separation is carried out in the high-pressure product separator at the pressure of 10MPa to 55MPa and the temperature of 110 ℃ to 320 ℃, the separated process gas enters a high-pressure circulating system, and the polymer enters a low-pressure separation device. And after the high-pressure circulating gas is separated by the high-pressure circulating preseparator, the high-pressure circulating gas enters a gas cooler for gradual cooling, so that the cooled high-pressure circulating gas system is ensured to enter the inlet temperature of the main compressor. The low molecular weight polymer separated from the process gas condensed by the gas cooler by the wax separating tank is discharged to the wax collecting tank through the wax removing valve at the bottom of the wax separating tank.
As shown in fig. 1 to 2, the present invention provides a low pressure separation apparatus applied to a high pressure polyethylene apparatus for receiving a polymer separated by a high pressure product separator,
comprising the following steps:
the cylinder body 4 is provided with a plurality of grooves,
the base 2 is arranged at the bottom of the cylinder 4 and is conical, and the included angle of the inner wall of the base 2 is 30-60 degrees, preferably 30-50 degrees.
The upper sealing head 7 is arranged at the top of the cylinder body 4 in a welding or flange connection mode,
a mixture inlet pipe 9 for introducing the molten mixture into the interior of the cylinder 4,
a gas outlet pipe 8 which is arranged on the upper sealing head 7 and is used for discharging unreacted polymer monomer and other light components,
a liquid outlet pipe 1 arranged at the bottom of the base 2 and used for discharging the polymer in liquid state,
wherein the ratio of the height of the low-pressure separation device to the cylinder 4 is 0.5 to 12, preferably the ratio is 2 to 10 and both are of internal dimensions,
the base 2 is provided with at least one radiation source 3 for measuring the filling level of the liquid component and a rod-like level detector 10, the rod-like level detector 10 records the level by measuring the attenuation of the radiation emitted by the radiation source after passing through the liquid in the cylinder 4,
the surface roughness of the inner wall of the low pressure separator is at most 0.8 μm.
Embodiment one:
as shown in fig. 1, when the upper end cap 7 is connected to the top of the cylinder 4 through a flange, the mixture inlet pipe 9 is connected to the center end of the upper end cap 7 in the vertical direction, and one end of the mixture inlet pipe 9 extending into the cylinder 4 is provided with a conical pipe 5 with an inner diameter gradually increasing in a direction away from the mixture inlet pipe 9.
The upper seal head 7 is a standard elliptical seal head, the length of the conical tube 5 is 15% -55%, preferably 20% -45% of the height of the cylinder 4, and the included angle of the inner wall of the conical tube 5 is 15-60 °, preferably 20-45 °.
In addition, at least 2 gas outlet pipes 8 are arranged on the upper sealing head 7, the ratio of the space between the central axis of each gas outlet pipe 8 and the central axis of the cylinder 4 to the inner diameter of the cylinder 4 is 0.20-0.35, preferably 0.25-0.33, and the included angle between the central axis of each gas outlet pipe 8 and the central axis of the cylinder 4 is 0-35, preferably 10-30.
Specifically, the inner diameter of the low-pressure separation device is 2000mm, the height of the interior of the container including the height of the base 2 is 5590mm, the height from the tangent line at the lower end of the cylinder 4 to the flange sealing surface is 3500mm, and the volume is 14.5m 3 The total amount of the flow of the molten mixture entering the low-pressure separator was 8850kg/h, the total amount of the flow of the liquid component separated in the low-pressure separator was 7000kg/h, the total amount of the flow of the gaseous component separated in the low-pressure separator was 1850kg/h, the ratio of the height to the inner diameter of the low-pressure separator was 2.8 at this time, the gas outlet pipes 8 were provided with 2 and the angle between the central axis of each gas outlet pipe 8 and the central axis of the cylinder 4 was 30 °.
At this time, the length of the conical tube 5 at the bottom of the mixture inlet tube was 2000mm, the vertical velocity of the rising gas in the region from the lower end of the conical tube 5 to the outlet of the gas outlet tube 8 was 0.126m/s, and the residence time was about 15s.
Embodiment two:
as shown in fig. 2 and 3, when the upper head 7 is welded to the top of the cylinder 4, the mixture inlet pipe 9 is provided in a bypass cyclone structure, i.e. is provided at the tangential end of the outer wall of the cylinder 4 and communicates with the cylinder 4 along the obliquely upper side of the cylinder 4,
the manhole 11 is obliquely arranged on the outer wall of the cylinder body 4, the included angle between the manhole 11 and the cylinder body 4 in the horizontal direction is 5-20 degrees, preferably 7-15 degrees, in addition, the gas outlet pipe 8 is arranged at the center end of the upper sealing head 7, and the anti-impact plate 13 is arranged on the inner wall of the cylinder body 4.
In particular, the method comprises the steps of,
the inner diameter of the low-pressure separation device is 2000mm, the height of the inside of the container including the height of the base 2 is 5590mm, the height from the tangent line at the lower end of the cylinder 4 to the welding surface is 3500mm, and the volume is 14.5m 3 The total amount of the flow of the molten mixture fed into the low-pressure separation apparatus was 8850kg/h, the total amount of the flow of the liquid component separated in the low-pressure separation apparatus was 7000kg/h, and the total amount of the flow of the gaseous component separated in the low-pressure separation apparatus was 1850kg/h, at which time the ratio of the height to the inner diameter of the low-pressure separation apparatus was 2.8.
The included angle between the center line of the mixture inlet pipe 9 and the horizontal direction of the cylinder 4 is 10 degrees, and the heat conductivity coefficient of the process gas which enters the inlet of the low-pressure circulating gas cooler after being separated by the low-pressure separating device is 0.056W/m-c.
Comparative example:
in the prior art, the upper seal head 7 is a spherical crown seal head, the inner diameter of the low-pressure separation device with a flange is 2000mm, the height of the interior of a container including the height of the base 2 is 5590mm, the height from the tangent line at the lower end of the cylinder 4 to the sealing surface of the flange is 3500mm, and the volume V is 14.5m 3 The total amount of the flow of the molten mixture fed into the low-pressure separation apparatus was 8850kg/h, the total amount of the flow of the liquid component separated in the low-pressure separation apparatus was 6800kg/h, and the total amount of the flow of the gaseous component separated in the low-pressure separation apparatus was 2050kg/h, at which time the ratio of the height to the inner diameter of the low-pressure separation apparatus was about 2.8.
The number of the gas outlet pipes 8 is one, the gas outlet pipes 8 are obliquely arranged on the outer wall of the cylinder body 4 downwards, and the included angle between the center line of the gas outlet pipes 8 and the horizontal direction of the low-pressure separation device is 30 degrees.
The distance from the intersection point of the center line of the gas outlet pipe 8 and the inner wall of the cylinder 4 to the flange sealing surface was 500mm.
The length of the mixture inlet pipe extending into the interior of the cylinder 4 at this time was 2000mm, the vertical velocity of the rising gas in the region from the lower end of the mixture inlet pipe to the outlet of the gas outlet pipe 8 was 0.14m/s, and the residence time was 5s at the minimum. The heat conductivity coefficient of the process gas which enters the inlet of the low-pressure circulating gas cooler after being separated by the low-pressure separation device is 0.062W/m-c.
In view of the above-mentioned, it is desirable,
example one the vertical velocity of the rising gas in the region from the lower end of the mixture inlet pipe to the outlet for the gas outlet pipe 8 was slower, the residence time was longer, and the gas-liquid separation effect was better than that of the comparative example one. The polymer entrained in the gas phase effluent of the low pressure separator can be reduced by 10% and the ethylene content of the polymer effluent can be reduced by 2% compared to the comparative example.
Compared with the comparative example, the heat conductivity coefficient of the process gas which enters the inlet of the low-pressure circulating gas cooler after being separated by the low-pressure separator in the second example can be reduced by 10%, the polymer carried in the gas-phase discharging of the low-pressure separator can be reduced by 10%, and the content of ethylene carried in the polymer discharging can be reduced by 2%.
Through the arrangement of the first embodiment and the second embodiment, the situation of gas-liquid entrainment phenomenon is reduced, namely, when the gas is separated at low pressure, the molten polymer is not easy to dope in the gas, thereby effectively ensuring the safe operation of the low pressure system device and prolonging the service life of the compressor.
In addition, by arranging the mixture inlet pipe 9 to be of a bypass type cyclone structure, through the rotation motion introduced tangentially by the airflow, the centrifugal force of the centrifugal force is larger to throw the liquid drops to the inner wall surface of the low-pressure separator, and the centrifugal force of the liquid drops is far larger than the gravity and the inertial force, so that the separation efficiency is higher compared with the prior art, and the structure is suitable for the operation condition that the flow speed of the mixture liquid drops entering the mixture inlet pipe 9 is higher;
when the mixture inlet pipe 9 is vertically arranged on the upper sealing head 7, gas-liquid separation is realized by arranging the conical pipe 5 and gravity sedimentation, in the process of dropping the mixture liquid drops, the size of the polymer liquid drops is continuously increased, and the gas phase entrainment force is relatively small, so that the gas-liquid separation is more favorable compared with the prior art, and the gas-liquid separation efficiency of the low-pressure separator is improved, and the economy is good.
Working principle: after the polymer enters the low-pressure separation device through the product valve, the pressure is reduced, 30% of ethylene and vinyl acetate monomer dissolved in the polymer are separated again, and the residual ethylene and vinyl acetate monomer in the polymer are continuously removed in the degassing bin.
Specifically, the molten mixture entering the low pressure separation device is polyethylene, unreacted polymer monomer and other light components; the separation process in the low pressure separation apparatus is performed at a pressure of 0.1MPag to 0.7MPag and a temperature of 110 ℃ to 320 ℃; unreacted polymer monomer and other light components are discharged in gaseous form from the gas outlet pipe 8 of the separator head 7, and polyethylene is discharged in liquid form from the liquid outlet pipe 1.
The foregoing has shown and described the basic principles, principal features and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, but is capable of various changes and modifications without departing from the spirit and scope of the invention. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (7)
1. A low pressure separator for use with a high pressure polyethylene device, comprising:
a cylinder (4),
a base (2) arranged at the bottom of the cylinder (4) and in a conical shape,
the upper sealing head (7) is an elliptic sealing head and is arranged at the top of the cylinder body (4) in a welding or flange connection mode,
a mixture inlet pipe (9) for introducing the molten mixture into the interior of the barrel (4),
a gas outlet pipe (8) which is arranged on the upper sealing head (7) and is used for discharging unreacted polymer monomer and other light components,
a liquid outlet pipe (1) arranged at the bottom of the base (2) and used for discharging the polymer in liquid state,
wherein, when the upper seal head (7) is welded at the top of the cylinder body (4), the mixture inlet pipe (9) is arranged in a bypass rotary separation structure, namely is arranged at the tangential end of the outer wall of the cylinder body (4) and is communicated with the cylinder body (4) along the inclined upper side of the cylinder body (4),
when upper head (7) pass through flange joint in barrel (4) top, mixture entry pipe (9) are in vertical direction intercommunication in upper head (7) central point, just stretch to the inside one end of barrel (4) in mixture entry pipe (9) along the direction of keeping away from mixture entry pipe (9) be provided with conical pipe (5) that the internal diameter increases gradually.
2. The low pressure separator for high pressure polyethylene device according to claim 1, wherein: the ratio of the height of the low-pressure separation device to the inner diameter of the cylinder (4) is 0.5-12.
3. The low pressure separator for high pressure polyethylene device according to claim 1, wherein: the included angle of the inner wall of the base (2) is 30-60 degrees.
4. The low pressure separator for high pressure polyethylene device according to claim 1, wherein: when the upper seal head (7) is connected to the top of the cylinder body (4) through a flange, the upper seal head (7) is a standard elliptical seal head, the length of the conical tube (5) is 15-55% of the height of the cylinder body (4), the included angle of the inner wall of the conical tube (5) is 15-60 degrees,
in addition, at least 2 gas outlet pipes (8) are arranged on the upper sealing head (7), the ratio of the distance between the central axis of each gas outlet pipe (8) and the central axis of the cylinder (4) to the inner diameter of the cylinder (4) is 0.20-0.35, and the included angle between the central axis of each gas outlet pipe (8) and the central axis of the cylinder (4) is 0-35 degrees.
5. The low pressure separator for high pressure polyethylene device according to claim 1, wherein: when the upper sealing head (7) is welded at the top of the cylinder body (4), a manhole (11) is obliquely arranged on the outer wall of the cylinder body (4), the included angle between the manhole (11) and the cylinder body (4) in the horizontal direction is 5-20 degrees,
in addition, the gas outlet pipe (8) is arranged at the center end of the upper sealing head (7), and a shock-proof plate (13) is arranged on the inner wall of the cylinder body (4).
6. The low pressure separator for high pressure polyethylene device according to claim 1, wherein: the base (2) is provided with at least one radiation source (3) for measuring the filling level height of the liquid component and a rod-shaped liquid level detector (10), and the rod-shaped liquid level detector (10) records the liquid level height by measuring the attenuation of the radiation emitted by the radiation source after passing through the liquid in the cylinder (4).
7. The low pressure separator for high pressure polyethylene device according to claim 1, wherein: the surface roughness of the inner wall of the low pressure separator is 0.8 μm at the maximum.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310578311.5A CN116617771A (en) | 2023-05-22 | 2023-05-22 | Be applied to low pressure separator on high pressure polyethylene device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310578311.5A CN116617771A (en) | 2023-05-22 | 2023-05-22 | Be applied to low pressure separator on high pressure polyethylene device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116617771A true CN116617771A (en) | 2023-08-22 |
Family
ID=87601955
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310578311.5A Pending CN116617771A (en) | 2023-05-22 | 2023-05-22 | Be applied to low pressure separator on high pressure polyethylene device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116617771A (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008093572A (en) * | 2006-10-12 | 2008-04-24 | Toshiba Corp | High-pressure fluid extraction system and apparatus therefor |
| CN202667011U (en) * | 2012-07-04 | 2013-01-16 | 上海三强不锈钢容器有限公司 | Cyclone separator for gas-liquid separation of food materials |
| CN105764932A (en) * | 2013-12-04 | 2016-07-13 | 巴塞尔聚烯烃股份有限公司 | Process for separating components of reaction mixture obtained by high-pressure polymerization of ethylenically unsaturated monomers with improved level control |
| CN105879501A (en) * | 2016-06-13 | 2016-08-24 | 杭州中能汽轮动力有限公司 | Steam-water separator |
| CN107074991A (en) * | 2014-11-13 | 2017-08-18 | 巴塞尔聚烯烃股份有限公司 | The component separation method of the polymer monomer mixture obtained by the high pressure polymerisation of ethylenically unsaturated monomer |
| CN206730695U (en) * | 2017-04-13 | 2017-12-12 | 广东美的智美科技有限公司 | Gas-liquid separation device |
| CN212188173U (en) * | 2019-12-30 | 2020-12-22 | 上海明罗石油天然气工程有限公司 | Gas-liquid separator with baffling assembly |
| CN215352481U (en) * | 2021-07-12 | 2021-12-31 | 中国核电工程有限公司 | Gas-liquid separation tank and gas-liquid separation system |
| CN216755700U (en) * | 2022-01-14 | 2022-06-17 | 武汉友谊食品工程有限公司 | Novel gas-liquid separator |
-
2023
- 2023-05-22 CN CN202310578311.5A patent/CN116617771A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008093572A (en) * | 2006-10-12 | 2008-04-24 | Toshiba Corp | High-pressure fluid extraction system and apparatus therefor |
| CN202667011U (en) * | 2012-07-04 | 2013-01-16 | 上海三强不锈钢容器有限公司 | Cyclone separator for gas-liquid separation of food materials |
| CN105764932A (en) * | 2013-12-04 | 2016-07-13 | 巴塞尔聚烯烃股份有限公司 | Process for separating components of reaction mixture obtained by high-pressure polymerization of ethylenically unsaturated monomers with improved level control |
| CN107074991A (en) * | 2014-11-13 | 2017-08-18 | 巴塞尔聚烯烃股份有限公司 | The component separation method of the polymer monomer mixture obtained by the high pressure polymerisation of ethylenically unsaturated monomer |
| CN105879501A (en) * | 2016-06-13 | 2016-08-24 | 杭州中能汽轮动力有限公司 | Steam-water separator |
| CN206730695U (en) * | 2017-04-13 | 2017-12-12 | 广东美的智美科技有限公司 | Gas-liquid separation device |
| CN212188173U (en) * | 2019-12-30 | 2020-12-22 | 上海明罗石油天然气工程有限公司 | Gas-liquid separator with baffling assembly |
| CN215352481U (en) * | 2021-07-12 | 2021-12-31 | 中国核电工程有限公司 | Gas-liquid separation tank and gas-liquid separation system |
| CN216755700U (en) * | 2022-01-14 | 2022-06-17 | 武汉友谊食品工程有限公司 | Novel gas-liquid separator |
Non-Patent Citations (1)
| Title |
|---|
| 凌立新，蒋山泉，鲁凌: "化工单元实训操作", 重庆大学出版社, pages: 134 - 135 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7837950B2 (en) | Apparatus for the production of polyethylene and ethylene copolymers | |
| KR102051767B1 (en) | A process for recovering hydrocarbons in a solution polymerisation process | |
| EP0801081B1 (en) | Method of drying solid polymer and drying apparatus | |
| BRPI0712710B1 (en) | Process for the production of polyethylene and ethylene copolymers, their use and apparatus for high pressure ethylene polymerization | |
| CA2975953C (en) | Process for separating hydrocarbons from polymer | |
| KR101857199B1 (en) | High Pressure Polymerization of Ethylenically Unsaturated Monomer in Tubular Reactor | |
| KR20090089346A (en) | High-pressure separator | |
| BR112017008449B1 (en) | PROCESS FOR SEPARATING A POLYMEROMONOMER MIXTURE AND PROCESS FOR PREPARING ETHYLENE HOMOPOLYMERS OR COPOLYMERS | |
| BR112016012152B1 (en) | container for separating components of a reaction mixture obtained by polymerization under high pressure of monomers with ethylenic unsaturation equipped with rupture discs, separation process and preparation process of homo or ethylene copolymers | |
| KR20150046208A (en) | Apparatus and process for making high-pressure polyethylene polymers and copolymers | |
| CN107949582B (en) | Cooling of high pressure polyethylene products | |
| WO2019230781A1 (en) | Method for producing ethylene-vinyl acetate copolymer | |
| EP3935090A1 (en) | Devolatilization of plastomer pellets | |
| CN116617771A (en) | Be applied to low pressure separator on high pressure polyethylene device | |
| US11549749B2 (en) | Pellet drying and degassing method | |
| CN111494976B (en) | Diluent removing device in slurry method polyethylene process | |
| CN212610377U (en) | Continuous solution polymerization device based on LCST | |
| KR102125192B1 (en) | Method for producing ethylene homopolymer or copolymer | |
| CN115008633B (en) | High-pressure separation device and method for separating polyolefin | |
| KR20180048752A (en) | Method for continuous polymerization of olefin monomers in a reactor | |
| CN213198379U (en) | Air-cooling granulating device | |
| JP6608573B1 (en) | Process for producing ethylene-vinyl acetate copolymer | |
| CN111848838B (en) | Method and apparatus for devolatilizing polymers | |
| CN116585831A (en) | High pressure separator and method for separating high pressure polyethylene copolymer or homopolymer from unreacted monomer and light component | |
| CN206188680U (en) | Can improve polypropylene device that tail gas recovery system retrieved propylene purity |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |