CN211246591U

CN211246591U - Large-volume polymerization kettle capable of enhancing gas-phase heat removal

Info

Publication number: CN211246591U
Application number: CN201921322430.XU
Authority: CN
Inventors: 翁汉生; 马文启; 韩磊; 武增辉
Original assignee: WEIHAI CHEMICAL MACHINERY CO Ltd
Current assignee: WEIHAI CHEMICAL MACHINERY CO Ltd
Priority date: 2019-08-15
Filing date: 2019-08-15
Publication date: 2020-08-14
Anticipated expiration: 2029-08-15

Abstract

The utility model provides a reinforce gaseous phase and remove big volume polymeric kettle of heat relates to chemical machinery's technical field, has solved among the prior art big volume polymeric kettle and has made the technical problem of product caking because of removing the heat capacity not enough in the polymerization later stage. The large-volume polymerization kettle for strengthening gas phase heat removal comprises a kettle body and a gas phase heat removal device, wherein the kettle body comprises a kettle barrel, a lower end enclosure and an upper end enclosure, and the lower end enclosure and the upper end enclosure are respectively connected with two ends of the kettle barrel. The gas phase heat removing device is positioned on the inner side and the outer side of the top of the kettle body, so that the gas phase heat removing device can remove heat in gas phase materials on the top of the kettle body. The gas phase heat removal device can remove heat to the inside gas phase material of polymeric kettle, utilizes the gas-liquid saturated vapor pressure state of material in the polymeric kettle, strengthens the condensation to the inside gas phase propylene of polymeric kettle, removes heat through latent heat of vaporization for big volume polymeric kettle also can effective control reaction process in the polymerization later stage, prevents the product caking phenomenon, has improved single cauldron conversion rate and product quality.

Description

Large-volume polymerization kettle capable of enhancing gas-phase heat removal

Technical Field

The utility model relates to a chemical machinery's technical field especially relates to a reinforce gaseous phase and remove big volume polymeric kettle of heat of intermittent type formula polypropylene production technology.

Background

The polypropylene production process can be classified into a liquid-phase bulk process, a liquid-phase bulk-gas-phase process combination process, a gas-phase process, and an intermittent liquid-phase bulk process according to the polymerization type. The intermittent liquid phase bulk method has the advantages of reliable technology, simple flow, flexible product grade conversion and the like. Each production line of the batch-type polypropylene liquid-phase bulk technique is provided with a propylene polymerization kettle with a stirrer.

During intermittent polypropylene production, liquid-phase propylene and a proper amount of catalyst, an activating agent, DDS, hydrogen and other auxiliaries are added into a propylene polymerization kettle according to 70% of the volume of the propylene polymerization kettle, and a spiral stirrer is used for stirring materials, so that the materials are uniformly mixed, the mass transfer and heat transfer effects are enhanced, and meanwhile, the contact heat exchange between the materials and the kettle wall and the inner cooling pipe is enhanced.

When polypropylene is produced, hot water is firstly introduced into a polymerization kettle jacket and an inner cooling pipe to heat liquid phase propylene in the kettle to about 60 ℃ so as to activate normal polymerization reaction, and then cold water and hot water are switched, namely circulating cooling water is introduced into the polymerization kettle jacket and the inner cooling pipe so that the circulating cooling water can withdraw the heat of polymerization reaction. It should be noted that the constant temperature reaction temperature of the materials in the kettle is finally maintained at 75 ℃, and the corresponding saturated vapor pressure is 3.4Mpa, so that the materials are subjected to polymerization reaction for 2-2.5 hours under the conditions. After the reaction is finished, recovering unreacted propylene, discharging and packaging the generated polypropylene powder after the combustible gas is replaced to be qualified.

In the production process of polypropylene, the phase state of propylene in a propylene polymerization kettle is changed along with the reaction time. When the reaction is started, the materials in the polymerization kettle are all liquid phase propylene, and at the moment, the heat transfer coefficient of the polymerization kettle is large, and the heat removal effect is good. As the reaction time is prolonged, the solid particles of polypropylene generated in the liquid phase propylene gradually increase, and the heat transfer coefficient of the polymerization kettle gradually decreases due to the poor heat transfer of the solid particles. At the later stage of the reaction, when the conversion rate of propylene is close to 70%, most of the materials in the kettle are solid polypropylene, liquid-phase propylene is little, the heat transfer coefficient of the polymerization kettle at the moment is reduced by about 36% compared with the initial stage of the reaction (see the production and application of polypropylene by a liquid-phase bulk method, the editions of Liyu, Chengning and the like, 9.1992, China petrochemical press, and for a large-volume polymerization kettle (the diameter is more than or equal to 2.4m), because the diameter of the kettle is large, a heat transfer device cannot be arranged in the middle of the kettle, stirring, mixing and heat transfer of the solid materials by a stirrer are delayed, and polymerization heat in the solid materials cannot be fully removed by utilizing a heat exchange mode that a polymerization kettle jacket and an inner cooling pipe are separated from the materials and heat is transferred through a kettle wall and an inner cooling pipe, so that the heat in the walls of the materials is accumulated more. In order to avoid the small caking phenomenon of the generated polypropylene powder due to local overheating, the reaction can only be ended in advance, and unreacted propylene is recovered, so that the conversion rate of a single kettle of a large-volume propylene polymerization kettle is limited to about 70 percent and is obviously behind the level of about 75 percent of the conversion rate of the single kettle of a small-volume polymerization kettle, and the large-scale development of the batch polymerization kettle is influenced.

Therefore, it is highly desirable to provide a polymerization reactor with enhanced heat removal capability at the later stage of polymerization reaction to increase the single-reactor conversion rate of a large-volume polymerization reactor.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a big volume polymeric kettle of intermittent type formula production polypropylene has solved among the prior art big volume polymeric kettle and has made the technical problem of product caking because of removing the heat ability not enough at the polymerization later stage. The utility model discloses preferred technical scheme can reach a great deal of beneficial technological effect, specifically says and explains below.

In order to achieve the above purpose, the utility model provides a following technical scheme:

the utility model discloses a polymeric kettle, including the cauldron body, gaseous phase heat removal device, the cauldron body includes cauldron barrel, low head and upper cover, and low head and upper cover are connected with the both ends of cauldron barrel respectively and are formed airtight space. The gas-phase heat removing device is positioned at the top of the kettle body or at the inner side and/or the outer side of the upper end enclosure, so that the gas-phase heat removing device can remove heat in gas-phase materials at the top of the kettle body.

As a preferred technical scheme, the gas phase heat removal device comprises a jacket, the diameter of the jacket is larger than that of the kettle body and is positioned on the outer side of the kettle body, and the top end of the jacket is higher than the joint of the upper end enclosure and the kettle barrel, so that the jacket can be sleeved on the outer side wall of the upper end enclosure.

As a preferred technical scheme, the top end of the jacket is positioned at the position of more than 50mm of the joint of the upper end enclosure and the kettle barrel through the joint of the sealing cover plate and the kettle body. Preferably, one end of the jacket, which is far away from the bottom of the kettle body, is higher than the joint of the upper seal head and the kettle body by 50-300 mm through the joint of the sealing cover plate and the kettle body.

As a preferred technical scheme, the jacket comprises a water outlet, the water outlet is provided with an elbow pipe, and one end of the elbow pipe, which is far away from the water outlet, is higher than the water outlet.

As a preferred technical scheme, a guide plate is arranged in the jacket, the guide plate is spiral, and the guide plate spirally rises along the outer wall of the kettle body, so that a spirally rising water flow channel is formed in the jacket.

As a preferable technical scheme, the jacket is further provided with baffle plates, the baffle plates are distributed on two sides of the water flow channel, and an included angle between the baffle plates and the flow direction of the liquid in the water flow channel is an acute angle, so that the inner diameter of the water flow channel at the baffle plates is gradually reduced along the flow direction of the liquid.

As a preferred technical scheme, the gas phase heat removal device comprises a heat removal coil, and the heat removal coil is positioned on the inner side of the top of the kettle body.

As a preferred technical scheme, the gas-phase heat removal device at least comprises a layer of heat removal coil pipe, and the heat removal coil pipe is spirally arranged along the inner wall of the upper end enclosure.

As a preferred technical scheme, the water inlet end and the water outlet end of the heat removing coil pipe are communicated with an external cooling water pipeline from the top of the upper seal head.

As a preferred technical scheme, the polymerization kettle further comprises a spiral-belt type stirrer, the spiral-belt type stirrer comprises a spiral belt, a transmission shaft, a clamping shell and a wide-plate end enclosure scraper, the upper end of the wide-plate end enclosure scraper and the bottom end of the spiral belt are arranged on a long support, and the bottom of the wide-plate end enclosure scraper is connected with an angle steel scraper in a supporting mode and is connected with the end portion of the transmission shaft through the clamping shell.

As a preferred technical scheme, the polymerization kettle further comprises an angle steel scraper support, the angle steel scraper support is positioned below the wide plate end enclosure scraper and is fixedly connected with the clamping shell, and the cutting edge curve of the angle steel scraper support is matched with the inner surface of the lower end enclosure.

The utility model provides a polymeric kettle has following beneficial technological effect at least:

the utility model discloses a to current polymeric kettle improve, increase gaseous phase and remove the heat facility on current polymeric kettle, make polymeric kettle not only strengthen and remove the heat ability, can also be at the polymerization later stage cauldron body heat transfer efficiency low, when the cauldron body can not withdraw from the reaction heat completely, utilize the gas-liquid saturated vapor pressure state of material in the polymeric kettle, remove the heat through the condensation and the latent heat of vaporization of strengthening to gaseous phase propylene in the polymeric kettle, make big volume polymeric kettle also can the effective control reaction process in the polymerization later stage, prevent the product caking phenomenon, single cauldron conversion rate and product quality have been improved.

Specifically, the liquid-phase propylene is vaporized by heat absorption, so that the heat in the solid-liquid mixed material in the kettle body is reduced. Further, the vaporized propylene rises to the top of the kettle body and is condensed, liquefied and refluxed through the gas phase heat removal device, and heat is carried out of the kettle body by cooling water in the gas phase heat removal device through the heat exchange mode. Because the propylene in the liquid phase in the kettle body continuously absorbs heat to be vaporized and the propylene in the gas phase is continuously liquefied, particularly, when the vaporization rate of the propylene is equal to the liquefaction rate of the propylene, the material in the kettle body reaches a gas-liquid equilibrium state. The gas phase heat removal device accelerates the liquefaction rate of gas phase propylene at the top of the kettle body, so that the latent heat of vaporization can be more effectively utilized for heat removal, the heat removal capability of the large-volume polymerization kettle in the later stage of polymerization reaction is enhanced, and the polymerization kettle can effectively control the stable operation of the polymerization reaction.

Furthermore, the utility model discloses preferred technical scheme can also produce following technological effect:

the utility model discloses well clamp cover top is higher than the junction of upper cover and cauldron barrel, and a large part of upper cover surface can be overlapped by the clamp promptly to make the cooling hydroenergy that presss from both sides in cover and the cauldron body formation seal space cover a most surface of upper cover, effectively increase heat transfer area, with improve heat exchange efficiency, and then be favorable to improving single cauldron conversion.

The utility model discloses the height that highly is not less than the height that presss from both sides the cover top of the delivery port of preferred technical scheme's clamp cover not only makes the cooling water can be full of and presss from both sides the cover, makes the cooling water cover and is pressed from both sides the cover and form the upper cover surface that sealed space wrapped up with the cauldron body for gaseous phase heat transfer area reaches the biggest, has improved gaseous phase heat exchange efficiency.

The utility model discloses the continuous linking setting that wide plate head scraper and oblique angle steel scraper supported of preferred technical scheme, in the polymerization later stage, solid-state material is many, when liquid phase propylene liquid level is low, the material of cauldron body bottom is turned to the top under the effect that the angle steel scraper supported, the material after turning up continues upwards turning through wide plate head scraper again, and then realized the continuous of material and turned, increase the solid-liquid mixed area, increase the influence range that liquid phase propylene vaporization latent heat was removed, full play polymerization later stage, the effect that the vaporization latent heat of utilization material was removed.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic view of a polymerizer, which is a preferred embodiment of the present invention;

FIG. 2 is a schematic view of a preferred embodiment baffle of the present invention;

FIG. 3 is a schematic illustration of a preferred embodiment wide plate end closure scraper and angle iron scraper support of the present invention;

FIG. 4 is a schematic view of the positional relationship between the jacket and the autoclave body according to a preferred embodiment of the present invention;

FIG. 5 is a schematic diagram of the positional relationship between a jacket and a kettle in the prior art.

In the figure: 1-a motor; 2, a speed reducer; 3-a frame; 4-mechanical sealing; 5, sealing the head; 6-a transmission shaft; 7-kettle body; 8-jacket; 9-cover plate; 10-kettle cylinder body; 11-a flow guide plate; 12-heat removal coils; 13-welding seam; 14-a water outlet; 15-existing jacket; 16-a coupling; 17-an internal cooling tube; 18-helical ribbon; 19-a cartridge; 20-a stirring shaft; 21-ribbon support; 22-long support; 23-end sealing scraper; 25-angle steel scraper support; 26-lower end enclosure; 27-a water inlet; 28-baffle plate; 29-jacket lower head; 30-jacket cylinder.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. It is to be understood that the embodiments described are only some embodiments of the invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Referring to fig. 1, the polymerization kettle of the preferred embodiment of the present invention comprises a kettle body 7, a heat exchange device, a stirring device, and a shaft seal. Preferably, the kettle body 7 comprises a kettle barrel body 10, a lower end enclosure 26 and an upper end enclosure 5. Further, the lower seal head 26 and the upper seal head 5 are respectively welded with two ends of the kettle cylinder 10 in a sealing manner to form a closed space.

Preferably, the heat exchange means comprises a gas phase heat removal means, a jacket and internal cooling tubes 17. Preferably, the inner cooling pipe 17 is arranged along the inner wall of the kettle barrel 10, and the gas phase heat removing device is arranged at the inner side and the outer side of the top of the kettle body 7.

Preferably, the solution of the polymerizer of the above preferred embodiment is applied to a large-capacity polymerizer. During the propylene constant temperature polymerization reaction, the material in the polymerization kettle is in a gas-liquid saturated vapor pressure state, and the solid material content in the solid-liquid mixed material is gradually increased along with the reaction, so that the heat removal efficiency of the kettle body 7 is reduced.

The polymerization kettle in the preferred embodiment utilizes the gas phase heat removal device to remove heat from the gas phase material at the top of the kettle body 7, and further, the gas phase heat removal condensation is strengthened to maintain the gas-liquid equilibrium state of the material in the kettle at a constant temperature, so that the large-volume polymerization kettle can still stably run in the later stage of the polymerization reaction, the technical bottleneck problem of large-scale application of the batch type reaction kettle is solved, and a foundation is laid for large-scale production of the batch type polypropylene device.

Referring to fig. 1, the gas phase withdrawing device comprises a top end part of a jacket 8, the diameter of the jacket 8 is larger than that of the kettle body 7, the jacket is positioned outside the kettle body 7, and the top end of the jacket 8 exceeds a connecting welding seam 13 between the upper end enclosure 5 and the kettle body 10, so that a closed space formed by the jacket 8 and the kettle body 7 can cover a part of the outer surface of the upper end enclosure 5.

As a preferred technical scheme, the top end of the jacket 8 is positioned at least 50mm above a welding line 13 for connecting the upper head 5 and the kettle cylinder 10. Preferably, the top end of the jacket is higher than the position 50 mm-350 mm above the welding line 13 for connecting the upper end enclosure 5 and the kettle cylinder 10. The increase of the height of the jacket not only can increase the heat exchange area of the upper end enclosure 5, but also prolongs the heat exchange time of the cooling water and the kettle body 7, and is beneficial to improving the heat exchange efficiency of the polymerization kettle. Specifically, taking a kettle body 7 with a nominal diameter of 2600mm as an example, when the jacket 8 is lifted by 250mm, the increased heat exchange area is 2.03 square meters, and further the heat exchange efficiency is improved.

Preferably, the inner diameter of the jacket 8 is larger than the outer diameter of the kettle body 7, so that a gap can be formed between the jacket 8 and the kettle body 7. Preferably, the jacket 8 comprises a sealing cover plate 9, a jacket cylinder 30 and a jacket lower end enclosure 29, wherein the jacket lower end enclosure 29 is connected with the jacket cylinder 30 and is sleeved outside the kettle cylinder 10 and the lower end enclosure 26, one side of the sealing cover plate 9 is hermetically welded with the uppermost end of the jacket cylinder 30, and the other side of the sealing cover plate 9 is hermetically welded with the outer surface of the upper end enclosure 5, so that a gap between the jacket cylinder 30 and the jacket lower end enclosure 29 as well as the kettle 7 is sealed through the sealing cover plate 9 to form a sealed space. Preferably, the sealing cover 9 is a horizontal plate. Set up sealed apron 9 to the flat board, can effectively reduce the sealed manufacturing difficulty that seals that presss from both sides cover 8.

The jacket of a preferred embodiment of the present application is formed by assembling and welding a jacket cylinder 30 and a jacket lower end enclosure 29. Preferably, the inner diameters of the jacket cylinder 30 and the jacket lower head 29 are 300mm larger than the outer diameter of the kettle body 7. After the jacket 8 is sleeved on the kettle body 7, the top end of the jacket 8 is higher than the welding line 13 connecting the kettle cylinder 10 and the upper end enclosure 5 by more than 50 mm. Preferably, the top end of the jacket 8 is 260mm higher than the welding seam 13 of the kettle barrel 10 and the upper end enclosure 5. The top end of the jacket cylinder 30 is sealed by a horizontal sealing cover plate 9. Specifically, the horizontal sealing cover plate 9 is welded with the top end of the jacket cylinder 30 and the outer surface of the upper end enclosure 5 respectively, so that a closed space is formed in a gap between the inner diameter of the jacket 8 and the outer diameter of the kettle body 7, the water level of cooling water in the jacket can rise to a position which is at least 50mm above the joint of the kettle cylinder 10 and the upper end enclosure 5, and preferably, the water level of the cooling water rises to a position which is 260mm above a welding seam 13, connected with the kettle cylinder 10 and the upper end enclosure 5.

As an alternative, the jacket that is sleeved on the upper end enclosure 5 may be provided separately from the jacket 8 that is sleeved on the kettle cylinder 10 and/or the lower end enclosure 26.

It should be noted that the height of the jacket in the prior art is mainly set according to the liquid level of the liquid-phase material in the kettle body 7. Specifically, referring to fig. 5, the height of the top end of the conventional jacket 15 is lower than the height of the weld 13 at the joint of the upper head 5 and the kettle cylinder 10.

Referring to fig. 1, the jacket includes a water outlet 14, and the water outlet 14 is provided with an elbow pipe, and one end of the elbow pipe away from the water outlet 14 is higher than the water outlet 14. The setting up of elbow pipe makes cooling water level improve and makes it can be full of the cavity between cover and the cauldron body 7, and then makes the surface that cooling water can fully cool off upper cover 5, and then improves cauldron internal gas phase material heat exchange efficiency.

Preferably, the jacket is also provided with a water inlet 27 to enable cooling water to enter the jacket from the water inlet 27. Further preferably, the water inlet 27 is located at the bottom of the jacket. Preferably, both the water inlet 27 and the water outlet 14 are connected to the circulating cooling water system so that cooling water cooled by the circulating cooling water system can enter the jacket through the water inlet 27, and the heat-absorbed cooling water can be discharged from the jacket through the water outlet 14 and enter the circulating cooling water system.

Referring to fig. 1, a guide plate 11 is arranged in the jacket, the guide plate 11 is spiral, and the guide plate 11 spirally rises from one end close to the bottom of the kettle body 7 to the high end far away from the bottom of the kettle body 7, so that a spirally rising water flow channel is formed in the jacket. Preferably, a double helix guide plate 11 is arranged in the jacket.

In the preferred embodiment, the spirally rising water flow channel formed in the jacket is communicated with the water outlet 14, so that the cooling water in the jacket can rise to the water outlet 14 at the top of the jacket along the spirally rising water flow channel and carry out reaction heat.

As a preferred embodiment, the guide plate 11 is welded on the outer wall of the kettle body 7 to increase the heat exchange area of the kettle body 7, and the gap between the guide plate 11 and the inner wall of the jacket 8 is small to prevent the cooling water in the jacket 8 from short-circuiting. Preferably, the gap between the baffle 11 and the inner wall of the jacket 8 is 4 mm.

Referring to fig. 2, baffles 28 are further disposed in the jacket 8, the baffles 28 are disposed on both sides of the water flow channel, and an included angle between the baffles 28 and a flow direction of the liquid in the water flow channel is an acute angle, so that an inner diameter of the water flow channel at the baffles 28 is gradually reduced along the flow direction of the liquid. Preferably, the baffles 28 are distributed offset over the baffle 11. Specifically, the baffle plate 28 can enable the water flow channel to be wide and narrow, and to be left and right, so that cooling water in the water flow channel can generate turbulence, the heat exchange coefficient of the kettle body 7 is increased, and heat removal of gas phase and/or liquid phase is enhanced.

Referring to fig. 1, the gas phase heat removing device comprises a heat removing coil 12, and the heat removing coil 12 is positioned on the inner side of the top of the kettle body 7. Preferably, the gas-phase heat-removing device at least comprises a layer of heat-removing coil 12, and the heat-removing coil 12 is spirally arranged along the inner wall of the upper head 5. Preferably, the gas phase heat removal means comprises three layers of heat removal coils 12. The heat exchange area of the gas phase heat removal can be effectively increased by arranging the heat removal coil 12. Specifically, taking the nominal diameter of the kettle body 7 as 2600mm as an example, every three layers of heat-removing coil pipes 12 can increase the heat exchange area of 0.97 square meters, thereby improving the gas-phase heat exchange efficiency.

In a preferred embodiment, the water inlet end and the water outlet end of the heat-removing coil 12 are communicated with an external cooling water pipeline from the top of the upper head 5.

Specifically, the cryogenic cooling water can enter the heat removal coil 12 from the water inlet end, and the cooling water absorbing heat through heat exchange is discharged from the water outlet end of the heat removal coil 12, so that the purpose of removing heat from the gas-phase material in the kettle body 7 is achieved. Preferably, the water inlet end and the water outlet end of the heat removing coil 12 are connected with the circulating cooling water system through pipelines, so that the cooling water cooled by the circulating cooling water system enters the heat removing coil 12 through the water inlet end of the heat removing coil 12, and the cooling water absorbing heat is discharged from the heat removing coil 12 and enters the circulating cooling water system for cooling. Preferably, the water inlet end and the water outlet end of the heat removing coil 12 are connected from the top of the upper head 5.

Referring to fig. 1, a preferred embodiment of the stirring apparatus of the polymerizer is located on the central axis of the body 7. Preferably, the stirring device comprises a helical ribbon stirrer and a transmission device, wherein the transmission device comprises a motor 1, a speed reducer 2, a frame 3, a mechanical seal 4 and an upper transmission shaft 6; the upper transmission shaft 6 extends into the kettle through the mechanical seal 4 and is connected with the stirring shaft 20 through the coupler 16.

Referring to fig. 1 or fig. 3, as a preferred embodiment, 8 jacketed shells 19 are installed on the stirring

shaft

20, 8 ribbon supports 21 welded on the 8 jacketed shells 19, and at least four coils of ribbons 18 are installed on the ribbon supports 21.

Preferably, the lowermost end of the stirring shaft 20 is provided with a pair of angle steel scraper supports 25 spaced 180 ° apart, and a pair of long supports 22 converging 180 ° are provided above the angle steel scraper supports 25. Preferably, the long support 22 crosses the angle blade support 25. Preferably, the long support 22 and the angle blade support 25 are perpendicular to each other. Specifically, the angle iron scraper supports 25 are respectively welded on a pair of clamping shells 19, and the clamping shells 19 are fastened at the bottom end of the stirring shaft 20 through bolts. The angle steel scraper support 25 not only can play a role in turning materials, but also can play a role in supporting the fixed end socket scraper 23, so that the stirring device is simple and practical in structure.

As a preferred embodiment of the present invention, the long support 22 is located 300mm above the angle iron scraper support 25. Preferably, a wide plate end sealing scraper 23 is further arranged on the stirring shaft 20. Preferably, the wide plate wiper blade 23 is helical. Specifically, one end of the wide plate end enclosure scraper 23 is connected with the upper end face of the angle steel scraper support 25, and the other end of the wide plate end enclosure scraper 23 is connected with the upper end face of the long support 22 after rising and rotating by 90 degrees according to the spiral angle. Preferably, the two wide plate end socket scrapers 23 are symmetrically distributed relative to the stirring shaft 20.

Referring to fig. 3, the included angle between the blade face of the angle iron scraper support 25 and the axis of the stirring shaft 20 is preferably an acute angle. Further preferably, the included angle between the blade face of the angle iron scraper support 25 and the axis of the stirring shaft 20 is 30 °.

In a preferred embodiment, the widest part of the wide-plate end-sealing blade 23 has a width of 300 mm.

In a preferred embodiment, the edge curve of the angle steel scraper support 25 is matched with the inner surface of the lower seal head 26, and preferably, the edge of the angle steel scraper support 25 is 16mm away from the inner surface of the bottom seal head.

The wide plate end enclosure scraper 23, the angle steel scraper support 25 and the installation positions thereof are designed, so that the solid materials at the bottom of the kettle body 7 can be upwards turned and moved under the action of the angle steel scraper support 25, the upwards turned materials of the angle steel scraper support 25 can be continuously upwards turned and moved through the widened wide plate end enclosure scraper 23, and the bottom of the kettle body 7 is continuously turned. Specifically, the motor 1 drives the stirring shaft 20 to rotate, drives the spiral belt 18, the end socket scraper 23 and the angle steel scraper support 25 to rotate, repeatedly lifts and back mixes materials, enables the materials to be uniformly mixed, and strengthens mass transfer and heat transfer effects.

In the preferred embodiment, the wide plate end enclosure scraper 23 and the angle steel scraper support 25 have a continuous upturning effect on the materials, so that the mixing range of the liquid phase propylene and the solid materials in the kettle body 7 is enlarged, the heat removal effect of the vaporization latent heat of the liquid phase propylene is enhanced, and especially, when the heat transfer efficiency of the solid materials is very low in the later stage of polymerization reaction, the important auxiliary heat removal effect is played, the small caking phenomenon caused by local overheating of polypropylene powder is avoided, and the product quality and the single kettle conversion rate of a polymerization kettle are improved.

The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and all should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A large-volume polymerization kettle with enhanced gas phase heat removal is characterized by comprising a kettle body (7) and a gas phase heat removal device, wherein the kettle body (7) comprises a kettle barrel (10), a lower end enclosure (26) and an upper end enclosure (5), and the lower end enclosure (26) and the upper end enclosure (5) are respectively connected with two ends of the kettle barrel (10);

the gas-phase heat removing device is positioned at the top of the kettle body (7) or at the inner side and/or the outer side of the upper end enclosure (5) so that the gas-phase heat removing device can remove heat in gas-phase materials at the top of the kettle body (7),

the gas phase heat removing device comprises a jacket (8) and at least one layer of heat removing coil (12), the diameter of the jacket (8) is larger than that of the kettle body (7), the jacket is positioned on the outer side of the kettle body (7), the top end of the jacket (8) is higher than the joint of the upper end enclosure (5) and the kettle barrel body (10),

the heat-removing coil (12) is positioned on the inner side of the top of the kettle body (7), and the heat-removing coil (12) is spirally arranged along the inner wall of the upper sealing head (5).

2. The polymerizer according to claim 1, wherein the jacket (8) comprises a water outlet (14), and wherein the water outlet (14) is provided with an elbow pipe, and wherein an end of the elbow pipe remote from the water outlet (14) is higher than the water outlet (14).

3. The polymerizer according to claim 1, wherein a guide plate (11) is arranged in the jacket (8), the guide plate (11) is spiral, and the guide plate (11) spirally rises along the outer wall of the tank body (7) to form a spirally rising water flow channel in the jacket (8).

4. The polymerizer according to claim 3, wherein baffles (28) are further disposed in the jacket (8), the baffles (28) are distributed on both sides of the water flow channel, and an included angle between the baffles (28) and a flow direction of the liquid in the water flow channel is an acute angle.

5. The polymerizer according to claim 4, wherein the water inlet end and the water outlet end of the heat-removing coil (12) are communicated with the pipeline of external cooling water from the top of the upper head (5).

6. The polymerizer according to any one of claims 1-4, further comprising a ribbon stirrer, wherein the ribbon stirrer comprises a ribbon (18), a transmission shaft (6), a clamping shell (19) and a wide-plate end-sealing scraper (23), wherein the upper end of the wide-plate end-sealing scraper (23) and the bottom end of the ribbon (18) are jointly connected with a long support (22), and the bottom of the wide-plate end-sealing scraper (23) is connected with an angle steel scraper support (25) and is connected with the end of the transmission shaft (6) through the clamping shell (19).

7. The polymerizer according to claim 6, further comprising an angle steel scraper support (25), wherein the angle steel scraper support (25) is located below the wide plate head scraper (23) and is fixedly connected with the shell (19), and a blade curve of the angle steel scraper support (25) is matched with an inner surface of the lower head (26).