CN112500506A - Intelligent strengthening system and process for preparing polyethylene based on solution method - Google Patents
Intelligent strengthening system and process for preparing polyethylene based on solution method Download PDFInfo
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- CN112500506A CN112500506A CN201910867760.5A CN201910867760A CN112500506A CN 112500506 A CN112500506 A CN 112500506A CN 201910867760 A CN201910867760 A CN 201910867760A CN 112500506 A CN112500506 A CN 112500506A
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- 238000000034 method Methods 0.000 title claims abstract description 59
- 239000004698 Polyethylene Substances 0.000 title claims abstract description 52
- -1 polyethylene Polymers 0.000 title claims abstract description 52
- 229920000573 polyethylene Polymers 0.000 title claims abstract description 52
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 11
- 238000005728 strengthening Methods 0.000 title claims abstract description 7
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims abstract description 111
- 239000005977 Ethylene Substances 0.000 claims abstract description 111
- 239000002904 solvent Substances 0.000 claims abstract description 105
- 238000001035 drying Methods 0.000 claims abstract description 42
- 238000003860 storage Methods 0.000 claims abstract description 39
- 239000007788 liquid Substances 0.000 claims abstract description 29
- 239000000839 emulsion Substances 0.000 claims abstract description 20
- 238000006116 polymerization reaction Methods 0.000 claims abstract description 14
- 238000012546 transfer Methods 0.000 claims abstract description 13
- 239000000463 material Substances 0.000 claims description 156
- 238000006243 chemical reaction Methods 0.000 claims description 84
- 239000007789 gas Substances 0.000 claims description 46
- 230000008569 process Effects 0.000 claims description 38
- 238000000926 separation method Methods 0.000 claims description 37
- 239000003054 catalyst Substances 0.000 claims description 16
- 239000012071 phase Substances 0.000 claims description 15
- 238000003756 stirring Methods 0.000 claims description 14
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 12
- 238000001704 evaporation Methods 0.000 claims description 11
- 230000008020 evaporation Effects 0.000 claims description 11
- 230000006835 compression Effects 0.000 claims description 10
- 238000007906 compression Methods 0.000 claims description 10
- 238000010992 reflux Methods 0.000 claims description 10
- 239000007791 liquid phase Substances 0.000 claims description 8
- 239000003139 biocide Substances 0.000 claims description 7
- 238000009835 boiling Methods 0.000 claims description 7
- 238000001514 detection method Methods 0.000 claims description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims description 6
- 229920000642 polymer Polymers 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 6
- 230000002787 reinforcement Effects 0.000 claims description 6
- 230000009471 action Effects 0.000 claims description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 3
- 239000001257 hydrogen Substances 0.000 claims description 3
- 229910052739 hydrogen Inorganic materials 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 238000010517 secondary reaction Methods 0.000 claims description 3
- 238000004807 desolvation Methods 0.000 claims 2
- 230000010259 detection of temperature stimulus Effects 0.000 claims 1
- 238000011897 real-time detection Methods 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 2
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- 238000002156 mixing Methods 0.000 description 5
- 125000000113 cyclohexyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C([H])([H])C1([H])[H] 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 238000012216 screening Methods 0.000 description 3
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical group CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000012968 metallocene catalyst Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
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- 239000004708 Very-low-density polyethylene Substances 0.000 description 1
- 239000011954 Ziegler–Natta catalyst Substances 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
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- 238000003795 desorption Methods 0.000 description 1
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- 238000000855 fermentation Methods 0.000 description 1
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- 238000005243 fluidization Methods 0.000 description 1
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- 230000006870 function Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229920001903 high density polyethylene Polymers 0.000 description 1
- 239000004700 high-density polyethylene Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229920000092 linear low density polyethylene Polymers 0.000 description 1
- 239000004707 linear low-density polyethylene Substances 0.000 description 1
- 239000002101 nanobubble Substances 0.000 description 1
- 239000007908 nanoemulsion Substances 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000007613 slurry method Methods 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 229920001866 very low density polyethylene Polymers 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 239000004711 α-olefin Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F110/02—Ethene
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
- B01J8/08—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with moving particles
- B01J8/10—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with moving particles moved by stirrers or by rotary drums or rotary receptacles or endless belts
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
The invention relates to an intelligent strengthening system and a process for preparing polyethylene based on a solution method, which comprises the following steps: ethylene storage tank, reactor, micro-interface generator, killer, desolventizing jar, rectifying column, flash tank, knockout drum, first drying tower, second drying tower and intelligent control unit. According to the invention, ethylene is crushed to form micron-sized bubbles with micron scale, and the micron-sized bubbles are mixed with the solvent to form gas-liquid emulsion, so that the phase interface area of gas-liquid two phases is increased, the thickness of a liquid film is reduced, the mass transfer resistance is reduced, and the mass transfer effect is enhanced within a lower preset operation condition range; meanwhile, each micron-sized bubble can be fully mixed with a solvent to form a gas-liquid emulsion, and the gas-liquid two phases are fully mixed, so that ethylene and an initiator in the system can be ensured to be fully contacted with the solvent, and the polymerization efficiency of the system is further improved.
Description
Technical Field
The invention relates to the technical field of polymer preparation, in particular to an intelligent reinforcement system and process for preparing polyethylene based on a solution method.
Background
Polyethylene processes are divided into low pressure processes for the production of LLDPE and HDPE and high pressure processes, for a total of three production processes, including slurry, gas phase and solution processes. The polymer in the slurry process is in a suspended state and is insoluble in alkane diluents; in the gas phase process, the polymer exists in a solid particle state in a stirred bed or a fluidized bed; in the solution process, the polymer is dissolved in a solvent.
At present, the polymerization of ethylene is mainly carried out by adopting a gas phase method in China, the gas phase method has lower investment and operation cost and less environmental pollution, but the reaction is difficult to control, and the product quality is relatively low; the liquid phase in France is almost zero, but the foreign related technologies are divided into slurry method and solution method, which are both to introduce the gas-phase monomer of ethylene into the solvent (also called viscosity-reducing agent or thinner), wherein the main component of the solvent is isopropanol, butanol, etc., the ethylene is introduced into the solvent in order to gradually polymerize the ethylene monomer in the solution to generate polyethylene target product and dissolve the polyethylene target product in the polyethylene target product, and then the solvent is volatilized by decompression and heating, and the product is separated out, solidified, granulated and formed.
The liquid phase method process is characterized in that: the method has the advantages of low requirement on raw materials, short reaction residence time, high polymerization reaction rate, short product switching time, solvent adoption, stable reaction, no scaling of a reactor, easy operation of opening and closing of a device, high conversion rate, capability of producing a full-range product (with molecular weight distribution ranging from narrow to wide) and very low-density polyethylene, capability of copolymerizing with high-grade alpha-olefin and excellent strength, toughness and sealing property.
However, in the prior art, ethylene is broken and dissolved in a solvent only by using a stirring manner of a stirring kettle, so that the ethylene cannot be fully mixed with the solvent, and the quality of a product prepared by the process is affected.
Disclosure of Invention
Therefore, the invention provides an intelligent reinforcement system and a process for preparing polyethylene based on a solution method, which are used for overcoming the problem of low system conversion rate caused by the fact that ethylene cannot be uniformly dissolved in a solvent in the prior art.
In one aspect, the present invention provides an intelligent reinforcement system for preparing polyethylene based on a solution method, comprising:
an ethylene storage tank for storing ethylene gas;
the reactor is connected with the ethylene storage tank and is used for providing a reaction space for the polymerization reaction of ethylene;
the micro-interface generator is arranged at the bottom end in the reactor and connected with the ethylene storage tank, converts pressure energy of gas and/or kinetic energy of liquid into bubble surface energy and transfers the bubble surface energy to ethylene gas, so that the ethylene gas is crushed into micron-sized bubbles with the diameter of more than or equal to 1 mu m and less than 1mm to improve the mass transfer area of a phase boundary, reduce the thickness of a liquid film and reduce mass transfer resistance, and materials are mixed to form a gas-liquid emulsion after being crushed so as to strengthen the mass transfer efficiency and the reaction efficiency between the phase boundaries within a preset operating condition range;
the killer is arranged at the outlet of the reactor and outputs killing agent into the system pipeline to kill the system when the reaction temperature in the system is higher than a specified value;
the desolventizing tank is arranged at the outlet of the flash tower, is connected with the flash tower and is used for separating the solvent in the reacted material;
the rectifying tower is arranged at the outlet of the desolventizing tank, is connected with the desolventizing tank and is used for rectifying the reacted materials;
the flash tank is arranged at the outlet of the mixer and connected with the mixer, reduces the pressure of the reacted materials to reduce the boiling point of the materials, evaporates the materials, and conveys the materials to the desolventizing tank and the rectifying tower respectively after evaporation;
the separation tank is arranged at the discharge port of the rectifying tower, connected with the discharge port of the rectifying tower and used for separating the rectified materials, and the outlet of the separation tank is connected with the ethylene storage tank and used for outputting the separated ethylene gas to a system or refluxing the separated ethylene gas to the ethylene storage tank;
the first drying tower is connected with the rectifying tower and used for removing moisture in the solvent output by the rectifying tower and refluxing the solvent to the reactor;
the second drying tower is connected with the separation tank and is used for removing moisture in the solvent output by the separation tank and refluxing the solvent to the reactor;
the intelligent control unit comprises a sensor, a controller and a cloud processor, the sensor transmits acquired electric signals to the cloud processor, the cloud processor performs screening comparison on reaction parameters returned by the sensor in a cloud database, and sends corresponding commands to the controller after an optimal control method is screened out, so that an optimal control function is realized.
Further, the reactor is a stirred tank, a feed inlet is formed in the side wall of the stirred tank and used for receiving the liquid-phase solvent, and a discharge outlet is formed in the bottom of the stirred tank and used for outputting the reacted materials.
Further, the reactor comprises a first reactor and a second reactor, wherein:
the first reactor is connected with the ethylene storage tank and used for receiving ethylene gas output by the ethylene storage tank, a first sensor is arranged on the inner wall of the first reactor and used for detecting reaction temperature and reaction pressure in the first reactor, and a first controller is arranged on the stirring engine of the first reactor and used for controlling the rotating speed of the engine so as to adjust the rotating speed of the stirrer;
the second reactor feed inlet links to each other with first reactor discharge gate for carry out the secondary reaction to the material of first reactor output, the second reactor inner wall is equipped with the second sensor for detect reaction temperature and reaction pressure in the second reactor, is equipped with the second controller on the second reactor stirring engine, is used for controlling the engine speed in order to adjust the agitator rotational speed.
Further, a flash sensor is arranged in the flash tank and used for detecting the temperature and the pressure in the flash tank in real time.
Further, the desolventizing tank comprises a first desolventizing tank and a second desolventizing tank, wherein:
the first desolventizing tank is connected with the flash tank and used for separating the solvent in the material output by the flash tank and respectively outputting the solvent to the second desolventizing tank and the rectifying tower;
the second desolventizing tank is connected with the first desolventizing tank and used for further separating the solvent in the material output by the first desolventizing tank and outputting the solvent to the rectifying tower, and a polymer outlet is formed in the bottom of the second desolventizing tank and used for outputting polyethylene.
Further, the rectifying column includes a light component column and a heavy component column, wherein:
the light component tower is respectively connected with the flash tank, the first desolventizing tank and the second desolventizing tank and is used for rectifying the materials for the first time, outputting the upper-layer materials to the separating tank after rectification and outputting the lower-layer materials to the heavy component tower, and a light component sensor is arranged in the light component tower and is used for detecting the rectification temperature in the light component tower in real time;
the heavy component tower is connected with a discharge port of the light component tower and used for receiving liquid-phase materials output by the light component tower, secondarily rectifying the materials, outputting upper-layer materials to the first drying tower after rectification, and discharging lower-layer heavy component materials out of the system, and a heavy component sensor is arranged in the heavy component tower and used for detecting the rectification temperature in the heavy component tower in real time.
Furthermore, a vacuum pump is arranged in a pipeline between the second desolventizing tank and the light component tower and used for outputting the solvent separated by the second desolventizing tank into the light component tower.
Furthermore, a compressor is arranged in an outlet pipeline of the separation tank and used for outputting the ethylene gas separated by the separation tank to a system or refluxing the ethylene gas to the ethylene storage tank, and a compression controller is arranged on the compressor and used for controlling the running power of the compressor so as to adjust the pressure of each device in the system.
Furthermore, the system is also provided with a plurality of heat exchangers, the heat exchangers are respectively arranged at the designated positions in the system and used for exchanging heat of materials in the system so as to adjust the operating temperature in the system, and each heat exchanger is provided with a heat exchange controller used for adjusting the temperature of a heat exchange medium so as to adjust the operating temperature of the system.
In another aspect, the present invention provides an intelligent enhanced process for preparing polyethylene based on a solution method, comprising:
step 1: before the system operates, introducing nitrogen, enabling the nitrogen to flow along the pipeline and fill the system to replace moisture and oxygen in the system, and after replacement is finished, introducing hydrogen into the material feeding pipeline to continue replacement;
step 2: after the replacement is finished, adding the catalyst, the cocatalyst and the electron donor into the first reactor and the second reactor respectively, conveying the solvent into the first reactor through the feed inlet, and allowing the solvent to flow into the second reactor through the discharge outlet of the first reactor;
and step 3: the system starts to operate, ethylene gas in the ethylene storage tank is respectively conveyed to a first micro-interface generator and a second micro-interface generator, each micro-interface generator can respectively crush the ethylene gas to form micron-sized bubbles, and the micron-sized bubbles are respectively output to a first reactor and a second reactor after being crushed;
and 4, step 4: the micron-sized bubbles are respectively output to a first reactor and a second reactor, the micron-sized bubbles are mixed with a solvent to form a gas-liquid emulsion, the gas-liquid emulsion is subjected to polymerization reaction under the action of a catalyst, a cocatalyst and an electron donor to generate polyethylene, during reaction, a first sensor can detect the reaction temperature and the reaction pressure in the first reactor in real time and transmit the measured data to a transport processor, and a second sensor can detect the reaction temperature and the reaction pressure in the second reactor in real time and transmit the measured data to a cloud processor;
and 5: after the reaction is finished, the second reactor outputs the mixed material containing polyethylene to a flash tank, the flash tank can reduce the pressure of the material, so that the boiling point of the material is reduced, the material is evaporated, in the evaporation process, a flash sensor can detect the temperature and the pressure in the flash tank in real time and transmit the measured data to a cloud processor, and after the evaporation is finished, the flash tank can output the upper-layer material to a light component tower and output the lower-layer material to a desolventizing tank;
step 6: after receiving the material output by the flash tank, the first desolventizing tank separates the solvent in the material, outputs the solvent to the light component tower and outputs the lower-layer material to the second desolventizing tank, and after receiving the material received by the first desolventizing tank, the second desolventizing tank secondarily separates the material, outputs the solvent to the light component tower and outputs the lower-layer polyethylene product to the system;
and 7: after the solvent is conveyed to the light component tower, the light component tower rectifies the solvent, the upper-layer material is output to a separation tank after rectification, the lower-layer material is output to a heavy component tower, the heavy component tower rectifies the material for the second time after the material is conveyed to the heavy component tower, the upper-layer material is output to a first drying tower after rectification, the lower-layer heavy component material is discharged out of the system, a light component sensor can detect the rectification temperature in the light component tower in real time in the rectification process and conveys the measured data to a cloud processor, and a heavy component sensor can detect the rectification temperature in the heavy component tower in real time and convey the measured data to the cloud processor;
and 8: the separation tank separates materials after receiving the materials, the separated materials are output to a system or flow back to the ethylene storage tank by the compressor, the materials on the lower layer are conveyed to the second drying tower to be dried, and flow back to the first reactor after being dried;
and step 9: the first drying tower is used for drying the upper-layer material output by the heavy component tower and refluxing the dried upper-layer material to the first reactor;
step 10: in the operation process of the system, the cloud processor receives detection data transmitted by the sensors, when at least one data exceeds a preset range, the cloud processor searches and screens an optimal solution in the cloud database, sends control signals to one or more of the first controller, the second controller, the compression controller and the heat exchange controller according to the optimal solution, and the controller receiving the control signals can adjust corresponding equipment so as to control designated process parameters in the system.
Compared with the prior art, the invention has the beneficial effects that ethylene is crushed to form micron-sized bubbles with micron scale, each micron-sized bubble can be fully mixed with a solvent to form a gas-liquid emulsion, and the ethylene and an initiator in the system can be ensured to be fully contacted with the solvent by fully mixing gas and liquid phases, so that the polymerization efficiency of the system is improved; meanwhile, the micron-sized bubbles are mixed with the solvent to form a gas-liquid emulsion, and the gas-liquid two-phase interfacial area is increased, the thickness of a liquid film is reduced, the mass transfer resistance is reduced, and the effect of strengthening mass transfer within a lower preset operating condition range is achieved.
In addition, the range of the preset operation condition can be flexibly adjusted according to different product requirements or different catalysts, so that the full and effective reaction is further ensured, the reaction rate is further ensured, and the purpose of strengthening the reaction is achieved.
Furthermore, the intelligent control unit is arranged in the system, can detect various parameters in the operation of the system through the sensor, performs screening comparison in the cloud database through the cloud processor, selects the optimal scheme to send an instruction to the controller so that the controller performs corresponding operation on the specified equipment, can complete automatic learning and regulation of the system through the cloud processor, improves the safety factor of the system, and further improves the operation efficiency of the system.
Furthermore, the system is also provided with a killer, and when the operating process parameters of the system exceed the specified values, the killer can deliver the killing agent into the system, so that the load of the system is adjusted, and the safety of the system is improved.
Further, the invention is provided with at least two drying towers which are used for respectively drying the solvent rectified by the rectifying tower, and the purity of the solvent is improved by removing moisture in the solvent, so that the solubility of the ethylene in the solvent is improved, and the conversion rate of the ethylene is further improved.
Further, the reactor selects a stirring kettle, the gas-liquid emulsion is stirred by using the stirring kettle so as to further mix micron-sized bubbles in the gas-liquid emulsion with the solvent, and the ethylene conversion rate of the system is further improved by improving the mixing degree of the micron-sized bubbles in the solvent.
In particular, the system of the invention adopts two reactors which are arranged in series, and the ethylene conversion rate of the system is further improved by using multi-stage reaction.
Furthermore, the system is also provided with two desolventizing tanks, and after the reaction of the gas-liquid emulsion is finished, the two desolventizing tanks can sequentially separate the materials after the reaction and separate the product from the solvent, so that the material use efficiency of the system is improved.
Furthermore, the system is also respectively provided with a light component tower and a heavy component tower, and after the solvent is conveyed to the rectifying tower, the light component tower and the heavy component tower can sequentially rectify the solvent so as to discharge heavy component materials in the solvent, so that the material use efficiency of the system is further improved.
Particularly, the heat exchangers are arranged at the designated positions in the system, and the heat exchangers are arranged at a plurality of designated positions, so that the temperature load of the system in the operation process can be effectively reduced, and the operation efficiency of the system is improved.
Drawings
FIG. 1 is a schematic structural diagram of an intelligent reinforcement system for preparing polyethylene based on a solution process according to the present invention;
FIG. 2 is a control flow chart of the intelligent reinforcing system for preparing polyethylene based on the solution method according to the present invention.
Detailed Description
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and do not limit the scope of the present invention.
It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
Fig. 1 is a schematic structural diagram of an intelligent reinforcement system for preparing polyethylene by a solution method according to the present invention, which includes an ethylene storage tank 1, a reactor 2, a micro-interface generator 3, a killer 4, a flash tank 5, a desolventizing tank 6, a vacuum pump 7, a rectifying tower 8, a first drying tower 91, a second drying tower 92, a separation tank 10, a compressor 11, a heat exchanger 12, and an intelligent controller (not shown in the figure). Wherein, the reactor 2 is connected with the ethylene storage tank 1 and is used for receiving the ethylene gas output by the ethylene storage tank 1 and providing a reaction site for the polymerization of ethylene. The micro-interface generator 3 is arranged at the bottom end of the reactor 2 and is used for crushing the ethylene gas output by the ethylene storage tank 1 to form micron-sized bubbles. The killer 4 is arranged at the discharge port of the reactor 3 and is used for releasing a killing agent to kill the system when the system is overloaded. The flash tank 5 is arranged at the outlet of the killer 4 and used for reducing the pressure of the material under the condition that the temperature is not changed, so that the boiling point of the material is reduced, and the material is evaporated. The desolventizing tank 6 is arranged between the flash tank 5 and the rectifying tower 8 and is used for separating the solvent and polyethylene products in the material output by the flash tank 5. The vacuum pump 7 is arranged at the outlet of the desolventizing tank 6 and used for conveying the solvent to the rectifying tower 8. And the rectifying tower 8 is respectively connected with the flash tank 5 and the desolventizing tank 6 and is used for rectifying the solvent to remove heavy component materials in the solvent. The first drying tower 91 is arranged at the outlet of the rectifying tower 8 and is used for drying the solvent output by the rectifying tower 8. The knockout drum sets up 8 exits in rectifying column for the ethylene gas in 8 output solvents of rectifying column. The second drying tower 92 is connected to the separation tank 10 for drying the solvent output from the separation tank 10. The compressor 11 is connected to the separation tank for delivering the ethylene output from the separation tank 10 to an ethylene storage tank or a discharge system. The heat exchangers 12 are respectively arranged at designated positions in the system and used for exchanging heat of materials in the system so as to adjust the operating temperature in the system. The intelligent controller is arranged outside the system and used for detecting and controlling various process parameters in the running process of the system in real time.
When the system operates, the ethylene storage tank 1 conveys ethylene gas to the micro-interface generator 3, the micro-interface generator 3 can crush the ethylene gas into micron-sized bubbles and output the micron-sized bubbles into the reactor 2, the micron-sized bubbles and a solvent are mixed to form a gas-liquid emulsion, and a polymerization reaction is carried out under the action of a catalyst to generate a mixed material containing polyethylene; after the reaction is finished, the reactor 2 conveys the mixed material to a flash tank 5, the flash tank 5 carries out flash evaporation on the mixed material to separate the material, the upper-layer material is conveyed to a rectifying tower 8 after separation, and the lower-layer material is conveyed to a desolventizing tank 6; the desolventizing tank 6 separates the received materials to obtain a mixed solvent and polyethylene, the mixed solvent is conveyed to the rectifying tower 8 after separation, and the polyethylene is output to a system; the rectifying tower 8 rectifies the mixed solvent, the upper-layer solvent is respectively conveyed to the first drying tower 91 and the separating tank 10 after rectification, and the lower-layer heavy component material is discharged out of the system; the first drying tower 91 dries the solvent output by the rectifying tower and reflows to the reactor 2 after drying; the separation tank separates the solvent, the upper layer of ethylene gas is conveyed to an ethylene storage tank 1 or an output system, and the lower layer of solvent is conveyed to a second drying tower 92; the second drying tower 92 dries the solvent and then returns the solvent to the reactor 2.
In the operation process of the system, the cloud processor receives detection data transmitted by the sensors, when at least one data exceeds a preset range, the cloud processor searches and screens an optimal solution in the cloud database, sends control signals to one or more of the first controller, the second controller, the compression controller and the heat exchange controller according to the optimal solution, and the controller receiving the control signals can adjust corresponding equipment so as to control designated process parameters in the system. It will be appreciated by those skilled in the art that the system can be used not only for the polymerization of ethylene, but also for the polymerization of polyvinyl chloride, propylene or other types of organic matter, provided that the system is capable of achieving its specified operating conditions.
Referring to fig. 1, the ethylene storage tank 1 of the present invention is a storage tank for storing ethylene gas, and when the system is in operation, the ethylene storage tank 1 outputs the ethylene gas to the micro-interface generator 3, and receives the ethylene output from the separation tank to reuse the ethylene. It is understood that the size and material of the ethylene storage tank 1 are not particularly limited in this embodiment, as long as the ethylene storage tank 1 can store and transport a specified amount of ethylene gas.
With continued reference to fig. 1, the reactor 2 includes a first reactor 21 and a second reactor 22, which are connected in series to perform a multi-stage reaction on ethylene. When the system is operated, the micro-interface generator 3 breaks the ethylene gas into micron-sized bubbles, the micron-sized bubbles are respectively output to the reactors, the micron-sized bubbles are dissolved in the solvent in each reactor and generate a polymerization reaction, after the reaction of the first reactor 21 is completed, the first reactor 21 conveys the mixed material to the second reactor 22 for a secondary reaction, and after the reaction of the second reactor 22 is completed, the mixed material is conveyed to the flash tank 5. It will be appreciated that the number of reactors may be two, three or another number, provided that the system is capable of multistage polymerisation of ethylene.
Specifically, the first reactor 21 is a stirred tank, a feed inlet is formed in the side wall of the stirred tank for receiving a solvent, a catalyst, a cocatalyst and an electron donor, a discharge outlet is formed in the bottom of the stirred tank for outputting a reacted mixed material, a micro-interface generator 3 is arranged at the bottom of the first reactor 21 for outputting micron-sized bubbles to the inside of the first reactor 21, a first sensor 211 is arranged on the inner wall of the first reactor 21 for detecting the reaction temperature and the reaction pressure of the first reactor 21, and a first controller 212 is arranged on a stirring engine of the first reactor 21 for controlling the rotating speed of the engine to adjust the rotating speed of the stirrer. When the system is operated, firstly, the solvent, the catalyst, the cocatalyst and the electron donor are sequentially introduced into the first reactor 21, at the moment, the micro-interface generator 3 outputs the micron-sized bubbles into the first reactor 21, the micron-sized bubbles are mixed with the materials in the first reactor 21 to form a gas-liquid emulsion, after the mixing is finished, the first reactor 21 starts to stir, so that the ethylene in the material is polymerized to generate polyethylene, and after the reaction is finished, the first reactor 21 outputs the reacted mixture containing polyethylene to the second reactor 22, during the operation of the first reactor 21, the first sensor 211 detects the reaction temperature and the reaction pressure of the first reactor 21 in real time, and transmits the measured data to the cloud processor, the first controller 221 receives a control signal transmitted from the cloud processor, and adjusting the stirring motor power in response to the control signal to control the reaction rate of the material in the first reactor 21. It is understood that the first reactor 21 may be a stirred tank, a suspended bed, a fluidized bed or other type of reactor, as long as the first reactor 21 can reach its designated operating state.
Specifically, the second reactor 22 is a stirred tank, a feed inlet is formed in a side wall of the stirred tank for receiving a solvent, a catalyst, a cocatalyst and an electron donor, a discharge outlet is formed in the bottom of the stirred tank for outputting a reacted mixture, a micro-interface generator 3 is arranged at the bottom of the second reactor 22 for outputting micron-sized bubbles to the inside of the second reactor 22, a second sensor 221 is arranged on the inner wall of the second reactor 22 for detecting the reaction temperature and the reaction pressure of the second reactor 22, and a second controller 222 is arranged on a stirring engine of the second reactor 22 for controlling the rotation speed of the engine to adjust the rotation speed of the stirrer. When the system is operated, the first reactor 21 conveys the reacted mixture to the inside of the second reactor 22, at this time, the micro-interface generator 3 outputs the micro-bubbles to the inside of the second reactor 22, the micro-bubbles are mixed with the mixture in the second reactor 22 to form a gas-liquid emulsion, after the mixing is completed, the second reactor 22 starts to stir, so that the ethylene in the material is polymerized to generate polyethylene, and after the reaction is finished, the first reactor 21 outputs the reacted mixture containing polyethylene to the flash tank 5, during the operation of the second reactor 22, the second sensor 221 detects the reaction temperature and the reaction pressure of the second reactor 22 in real time, and transmits the measured data to the cloud processor, the second controller 222 receives a control signal transmitted from the cloud processor, and adjusting the stirring motor power in response to the control signal to control the rate of reaction of the material in the second reactor 22. It is understood that the second reactor 22 can be a stirred tank, a suspended bed, a fluidized bed or other type of reactor, as long as the second reactor 22 can achieve its specified operating condition.
Referring to fig. 1, the micro-interface generator 3 of the present invention includes a first micro-interface generator 31 and a second micro-interface generator 32. Wherein the first micro-interface generator 31 is disposed at the bottom side of the first reactor 21 for breaking the ethylene gas into micro-bubbles and outputting the micro-bubbles to the inside of the first reactor 21. The second micro-interface generator 32 is disposed at the bottom side of the interior of the second reactor 22, and is used for breaking the ethylene gas into micro-bubbles and outputting the micro-bubbles to the interior of the second reactor 22. When the system is in operation, each micro-interface generator 3 can respectively smash the conveyed ethylene gas, so that the ethylene gas is smashed to form micron-sized bubbles, and the micron-sized bubbles are respectively output to the corresponding reactors 2, so that the micron-sized bubbles and the materials in each reactor 2 are mixed to form a gas-liquid emulsion. It is understood that the micro-interface generator 3 of the present invention can also be used in other multi-phase reactions, such as multi-phase fluid formed by micro-scale particles, micro-nano-scale particles, micro-bubble fluid, micro-bubble fluid, micro-bubble fluid, micro-bubble fluid, micro-foam, micro-bubble fluid, micro-nano-emulsion fluid, micro-phase micro-structure fluid, micro-liquid-solid micro-mixed fluid, micro-liquid-solid micro-nano fluid, micro-liquid-solid emulsion fluid, micro-liquid, micro-bubble fluid, micro-dispersed fluid, two micro-mixed fluid, micro-turbulent fluid, micro-bubble fluid, micro-bubble fluid, micro-nano-bubble fluid, and micro-bubble fluid, by using micro-mixing, micro-fluidization, micro-bubble fermentation, micro-bubble bubbling, micro-bubble mass, Or multiphase fluid (micro interface fluid for short) formed by micro-nano-scale particles, thereby effectively increasing the phase boundary mass transfer area between the gas phase and/or the liquid phase and/or the solid phase in the reaction process.
With continued reference to fig. 1, the killer 4 of the present invention is disposed at the outlet of the second reactor 22 to deliver the killing agent into the system to kill the system when the system is under high operating load. Before the system operates, a preset temperature value and a preset pressure value are set in the killer 4, and when the pressure or the temperature in the system is greater than the preset value during the system operation, the killer 4 can convey a specified amount of the killing agent into the system, so that the operating load in the system is reduced. It will be appreciated that the killing agent may be of the type CO, or may be of another type, provided that the killer 4 is effective in reducing the operational load on the system when it is released.
Referring to fig. 1, the flash tank 5 is disposed at the outlet of the killer 4, and a flash sensor 51 is disposed inside the flash tank for flashing the mixture to detect the temperature and pressure inside the flash tank 5. When the mixed material is conveyed to the flash tank 5 by the second reactor 22, the flash tank 5 flashes the reacted mixed material, reduces the boiling point of the mixed material by reducing the pressure of the reacted mixed material, so as to evaporate the mixed material, separates the mixed material after evaporation, conveys the upper-layer material to the rectifying tower 8, conveys the lower-layer material to the desolventizing tank 6, and detects the temperature and pressure in the flash tank 5 in real time by the flash sensor 51 during the flash process, and conveys the measured data to the cloud processor. It is understood that the size and type of the flash tank 5 are not particularly limited in this embodiment, as long as the flash tank 5 can reach its designated operating state.
With continued reference to FIG. 1, the desolventizing tank 6 according to the embodiment of the present invention includes a first desolventizing tank 61 and a second desolventizing tank 62. The first desolventizing tank 61 is connected with the flash tank and used for removing the solvent from the lower-layer material output by the flash tank 5. The second desolventizing tank 62 is connected to the first desolventizing tank 61, and is used for separating the material separated by the first desolventizing tank 61 to obtain the mixed solvent containing ethylene and polyethylene. When the system is in operation, the flash tank can carry lower floor's material to first desolventizing jar 61, and first desolventizing jar can separate lower floor's material to carry the mixed solvent on upper strata after the separation extremely rectifying column 8 carries lower floor's material to second desolventizing jar 62, and after lower floor's material got into second desolventizing jar 62, second desolventizing jar 62 can carry out the desorption of solvent to the material, carried upper mixed solvent to rectifying column 8 after deviating from, with the polyethylene output system of lower floor. It is understood that the number of the desolventizing tank 6 may be two, three or other numbers as long as the desolventizing tank 6 can separate the mixed solvent from the polyethylene and output the polyethylene out of the system.
With continued reference to fig. 1, the rectification column 8 according to the present invention includes a light component column 81 and a heavy component column 82. The light component tower 81 is connected to the flash tank 5, the first desolventizing tank 61 and the second desolventizing tank 62, and is configured to receive the mixed solvent output by the flash tank 5, the first desolventizing tank 61 and the second desolventizing tank 62 and rectify the mixed solvent, and a light component sensor 811 is disposed inside the light component tower 81 and is configured to detect a rectification temperature inside the light component tower 81. The heavy component tower 82 is connected with the light component tower 81 and is used for rectifying the mixed solvent output from the lower layer of the light component tower, and a heavy component sensor 821 is arranged in the heavy component tower 82 and is used for detecting the rectifying temperature in the heavy component tower 82. When the mixed solvent is conveyed to the inside of the light component tower 81, the light component tower 81 rectifies the mixed solvent, after rectification, the upper layer of the mixed solvent containing ethylene is output to the separation tank 10, the lower layer of the mixed solvent is conveyed to the heavy component tower 82, the heavy component tower 81 rectifies the mixed solvent, after rectification, the heavy component tower 82 conveys the upper layer of the solvent to the first drying tower 91, the lower layer of the heavy component material is output to the system, during rectification, the light component sensor 811 detects the rectification temperature in the light component tower 81 in real time and conveys the measured temperature to the cloud processor, and the heavy component sensor 821 detects the rectification temperature in the heavy component tower 82 in real time and conveys the measured temperature to the cloud processor. It is to be understood that the size and type of the light component tower 81 and the heavy component tower 82 are not particularly limited in this embodiment, as long as the light component tower 81 and the heavy component tower 82 can respectively reach their designated operating states.
With continued reference to fig. 1, the first drying tower 91 is disposed at the outlet of the heavies tower 82 for drying the solvent from the heavies tower 82 to improve the purity of the solvent by removing water from the solvent.
With continued reference to fig. 1, the knockout drum 10 of the present invention is connected to the light component tower 81 for separating the mixed solvent outputted from the light component tower 81. After the mixed solvent is output to the separation tank 10 by the light component tower 81, the separation tank 10 separates the mixed solvent, outputs the upper-layer ethylene to the ethylene storage tank 1 for reuse after separation, and outputs the lower-layer solvent to the second drying tower.
With continued reference to fig. 1, the second drying tower of the present invention is connected to the knockout drum for drying the solvent output from the knockout drum 10. When the system is operated, the second drying tower 92 receives the solvent output from the separation tank 10 and removes moisture from the solvent to increase the purity of the solvent, and after the drying is completed, the second drying tower 92 returns the solvent to the first reactor for reuse.
Referring to fig. 1, the compressor 11 of the present invention is connected to the separation tank 10 for delivering the ethylene gas output from the separation tank 10 to the ethylene storage tank 1 or the output system, and the compressor 11 is provided with a compression controller 111 for controlling the operation power of the compressor to adjust the pressure in the system. When the system is running, the compressor 11 starts to operate and delivers the ethylene gas in the separation tank 10 to the ethylene storage tank 1 or the output system, and after the cloud processor delivers a control signal to the compression controller 111, the compression controller 111 adjusts the power of the compressor 11, thereby controlling the pressure in the system. It is understood that the type and model of the compressor 11 are not particularly limited in this embodiment, as long as the compressor 11 can achieve its designated operating state.
With reference to fig. 1, the heat exchangers 12 of the present invention are respectively disposed at the outlet of the ethylene storage tank 1, the outlet of the first reactor 21, the outlet of the killer 4, the upper and lower outlets of the light component tower 81, the upper and lower outlets of the heavy component tower 82, and the inlet of the separation tank. The heat exchanger 12 is provided with a heat exchange controller 121 for controlling the operating temperature of the system. When the system is running, after the cloud processor transmits a control signal to the designated heat exchange controller 121, the heat exchange controller 121 can adjust the temperature of the heat exchange medium, thereby completing the adjustment of the running temperature of the system.
Referring to fig. 1 and 2, the intelligent control unit according to the present invention includes a sensor, a controller and a cloud processor, wherein the sensor includes a first sensor 211, a second sensor 221, a flash evaporation sensor 51, a light component sensor 811 and a heavy component sensor 821, and the controller includes a first controller 2121, a second controller 222, a compression controller 111 and a heat exchange sensor 121. The cloud processor is arranged outside the system, is respectively connected with the sensors and the controllers, and is used for receiving the electric signals sent by the sensors and transmitting the control signals to the controllers after screening and adjusting.
When the system is in operation, each sensor can detect the temperature and the pressure in the designated equipment in real time, and transmits the detection result to the cloud processor in real time in an electric signal mode after the detection is finished, when the reaction temperature or the reaction pressure exceeds a preset range, the cloud processor can screen in the cloud database to select an optimal processing scheme and send a control signal to each controller, and each controller starts to control the designated equipment after receiving the control signal, so that the adjustment of the reaction temperature and the reaction pressure in the system is finished. It is understood that the type and model of each sensor is not particularly limited in this embodiment, as long as each sensor can detect the reaction temperature and the reaction pressure in the system. Of course, the connection manner between each sensor and each controller and the cloud processor is not particularly limited in this embodiment, as long as the requirement that each sensor can transmit an electrical signal to the cloud processor and the requirement that the cloud processor can transmit a control signal to each controller is met.
In order that the objects and advantages of the invention will be more clearly understood, the invention is further described below with reference to examples; it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
An intelligent strengthening process for preparing polyethylene based on a solution method is characterized by comprising the following steps:
step 1: before the system operates, introducing nitrogen, enabling the nitrogen to flow along the pipeline and fill the system to replace moisture and oxygen in the system, and after replacement is finished, introducing hydrogen into the material feeding pipeline to continue replacement;
step 2: after the replacement is finished, adding the catalyst, the cocatalyst and the electron donor into the first reactor and the second reactor respectively, conveying the solvent into the first reactor through the feed inlet, and allowing the solvent to flow into the second reactor through the discharge outlet of the first reactor;
and step 3: the system starts to operate, ethylene gas in the ethylene storage tank is respectively conveyed to a first micro-interface generator and a second micro-interface generator, each micro-interface generator can respectively crush the ethylene gas to form micron-sized bubbles, and the micron-sized bubbles are respectively output to a first reactor and a second reactor after being crushed;
and 4, step 4: the micron-sized bubbles are respectively output to a first reactor and a second reactor, the micron-sized bubbles are mixed with a solvent to form a gas-liquid emulsion, the gas-liquid emulsion is subjected to polymerization reaction under the action of a catalyst, a cocatalyst and an electron donor to generate polyethylene, during reaction, a first sensor can detect the reaction temperature and the reaction pressure in the first reactor in real time and transmit the measured data to a transport processor, and a second sensor can detect the reaction temperature and the reaction pressure in the second reactor in real time and transmit the measured data to a cloud processor;
and 5: after the reaction is finished, the second reactor outputs the mixed material containing polyethylene to a flash tank, the flash tank can reduce the pressure of the material, so that the boiling point of the material is reduced, the material is evaporated, in the evaporation process, a flash sensor can detect the temperature and the pressure in the flash tank in real time and transmit the measured data to a cloud processor, and after the evaporation is finished, the flash tank can output the upper-layer material to a light component tower and output the lower-layer material to a desolventizing tank;
step 6: after receiving the material output by the flash tank, the first desolventizing tank separates the solvent in the material, outputs the solvent to the light component tower and outputs the lower-layer material to the second desolventizing tank, and after receiving the material received by the first desolventizing tank, the second desolventizing tank secondarily separates the material, outputs the solvent to the light component tower and outputs the lower-layer polyethylene product to the system;
and 7: after the solvent is conveyed to the light component tower, the light component tower rectifies the solvent, the upper-layer material is output to a separation tank after rectification, the lower-layer material is output to a heavy component tower, the heavy component tower rectifies the material for the second time after the material is conveyed to the heavy component tower, the upper-layer material is output to a first drying tower after rectification, the lower-layer heavy component material is discharged out of the system, a light component sensor can detect the rectification temperature in the light component tower in real time in the rectification process and conveys the measured data to a cloud processor, and a heavy component sensor can detect the rectification temperature in the heavy component tower in real time and convey the measured data to the cloud processor;
and 8: the separation tank separates materials after receiving the materials, the separated materials are output to a system or flow back to the ethylene storage tank by the compressor, the materials on the lower layer are conveyed to the second drying tower to be dried, and flow back to the first reactor after being dried;
and step 9: the first drying tower is used for drying the upper-layer material output by the heavy component tower and refluxing the dried upper-layer material to the first reactor;
step 10: in the operation process of the system, the cloud processor receives detection data transmitted by the sensors, when at least one data exceeds a preset range, the cloud processor searches and screens an optimal solution in the cloud database, sends control signals to one or more of the first controller, the second controller, the compression controller and the heat exchange controller according to the optimal solution, and the controller receiving the control signals can adjust corresponding equipment so as to control designated process parameters in the system.
Example one
The preparation of polyethylene is carried out using the above system and process, wherein:
the reaction temperature in the reactor is 153 ℃, the reaction pressure is 2.4MPa, the solvent is cyclohexane, and the catalyst is a Ziegler-Natta catalyst.
After the system is operated, the product is counted, the single-pass conversion rate of the ethylene is 96.8 percent, and the total utilization rate is 98.5 percent.
Example two
The preparation of polyethylene is carried out using the above system and process, wherein:
the reaction temperature in the reactor is 158 ℃, the reaction pressure is 2.9MPa, the solvent is cyclohexane, and the catalyst is non-metallocene single-site catalyst (SSC).
The product is counted after the system is operated, the single-pass conversion rate of the ethylene is 98.2 percent, and the total utilization rate is 98.9 percent.
EXAMPLE III
The preparation of polyethylene is carried out using the above system and process, wherein:
the reaction temperature in the reactor is 162 ℃, the reaction pressure is 3.2MPa, the solvent is cyclohexane, and the catalyst is Z-N metallocene catalyst.
The product is counted after the system is operated, the single-pass conversion rate of the ethylene is 98.8 percent, and the total utilization rate is 99.4 percent.
Comparative example
The preparation of polyethylene was carried out using the prior art, in which:
the reaction temperature in the reactor is 162 ℃, the reaction pressure is 3.2MPa, the solvent is cyclohexane, and the catalyst is Z-N metallocene catalyst.
The product is counted after the system is operated, the single-pass conversion rate of the ethylene is 95 percent, and the total utilization rate is 98.5 percent.
Therefore, the system and the process can effectively improve the single-pass conversion rate of the ethylene and the utilization rate of the ethylene.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention; various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. An intelligent enhancement system for preparing polyethylene based on a solution method is characterized by comprising the following steps:
an ethylene storage tank for storing ethylene gas;
the reactor is connected with the ethylene storage tank and is used for providing a reaction space for the polymerization reaction of ethylene;
the micro-interface generator is arranged at the bottom end in the reactor and connected with the ethylene storage tank, converts pressure energy of gas and/or kinetic energy of liquid into bubble surface energy and transfers the bubble surface energy to ethylene gas, so that the ethylene gas is crushed into micron-sized bubbles with the diameter of more than or equal to 1 mu m and less than 1mm to improve the mass transfer area of a phase boundary, reduce the thickness of a liquid film and reduce mass transfer resistance, and materials are mixed to form a gas-liquid emulsion after being crushed so as to strengthen the mass transfer efficiency and the reaction efficiency between the phase boundaries within a preset operating condition range;
the killer is arranged at the outlet of the reactor and outputs killing agent into the system pipeline to kill the system when the reaction temperature in the system is higher than a specified value;
the desolventizing tank is arranged at the outlet of the flash tower, is connected with the flash tower and is used for separating the solvent in the reacted material;
the rectifying tower is arranged at the outlet of the desolventizing tank, is connected with the desolventizing tank and is used for rectifying the reacted materials;
the flash tank is arranged at the outlet of the mixer and connected with the mixer, reduces the pressure of the reacted materials to reduce the boiling point of the materials, evaporates the materials, and conveys the materials to the desolventizing tank and the rectifying tower respectively after evaporation;
the separation tank is arranged at the discharge port of the rectifying tower, connected with the discharge port of the rectifying tower and used for separating the rectified materials, and the outlet of the separation tank is connected with the ethylene storage tank and used for outputting the separated ethylene gas to a system or refluxing the separated ethylene gas to the ethylene storage tank;
the first drying tower is connected with the rectifying tower and used for removing moisture in the solvent output by the rectifying tower and refluxing the solvent to the reactor;
the second drying tower is connected with the separation tank and is used for removing moisture in the solvent output by the separation tank and refluxing the solvent to the reactor;
the intelligent control unit comprises sensors and controllers which are respectively arranged on the designated equipment, and cloud processors which are arranged outside the system and are respectively connected with the sensors and the controllers, wherein the sensors transmit acquired electric signals to the cloud processors, the cloud processors screen and compare reaction parameters returned by the sensors in a cloud database, and send corresponding commands to the controllers after an optimal control method is screened out, so that the optimal control function is realized.
2. The intelligent enhancement system for preparing polyethylene based on solution process as claimed in claim 1, wherein the reactor is a stirred tank, the side wall of the stirred tank is provided with a feeding hole for receiving liquid phase solvent, and the bottom of the stirred tank is provided with a discharging hole for outputting reacted materials.
3. The intelligent solution process-based polyethylene intensive system according to claim 2, wherein the reactor comprises a first reactor and a second reactor, wherein:
the first reactor is connected with the ethylene storage tank and used for receiving ethylene gas output by the ethylene storage tank, a first sensor is arranged on the inner wall of the first reactor and used for detecting reaction temperature and reaction pressure in the first reactor, and a first controller is arranged on the stirring engine of the first reactor and used for controlling the rotating speed of the engine so as to adjust the rotating speed of the stirrer;
the second reactor feed inlet links to each other with first reactor discharge gate for carry out the secondary reaction to the material of first reactor output, the second reactor inner wall is equipped with the second sensor for detect reaction temperature and reaction pressure in the second reactor, is equipped with the second controller on the second reactor stirring engine, is used for controlling the engine speed in order to adjust the agitator rotational speed.
4. The intelligent solution process-based polyethylene enhancement system according to claim 1, wherein a flash sensor is provided in the flash tank for real-time detection of temperature and pressure in the flash tank.
5. The intelligent solution process-based polyethylene intensive system of claim 1, wherein the desolventizing tank comprises a first desolventizing tank and a second desolventizing tank, wherein:
the first desolventizing tank is connected with the flash tank and used for separating the solvent in the material output by the flash tank and respectively outputting the solvent to the second desolventizing tank and the rectifying tower;
the second desolventizing tank is connected with the first desolventizing tank and used for further separating the solvent in the material output by the first desolventizing tank and outputting the solvent to the rectifying tower, and a polymer outlet is formed in the bottom of the second desolventizing tank and used for outputting polyethylene.
6. The intelligent solution-based polyethylene production enhancement system according to claim 5, wherein the rectification column comprises a light component column and a heavy component column, wherein:
the light component tower is respectively connected with the flash tank, the first desolventizing tank and the second desolventizing tank and is used for rectifying the materials for the first time, outputting the upper-layer materials to the separating tank after rectification and outputting the lower-layer materials to the heavy component tower, and a light component sensor is arranged in the light component tower and is used for detecting the rectification temperature in the light component tower in real time;
the heavy component tower is connected with a discharge port of the light component tower and used for receiving liquid-phase materials output by the light component tower, secondarily rectifying the materials, outputting upper-layer materials to the first drying tower after rectification, and discharging lower-layer heavy component materials out of the system, and a heavy component sensor is arranged in the heavy component tower and used for detecting the rectification temperature in the heavy component tower in real time.
7. The intelligent enhancement system for preparing polyethylene by the solution-based method according to claim 6, wherein a vacuum pump is disposed in the pipeline between the second desolvation tank and the light component tower, so as to output the solvent separated by the second desolvation tank into the light component tower.
8. The intelligent reinforcement system for polyethylene preparation based on solution process as claimed in claim 1, wherein the outlet pipeline of the separation tank is provided with a compressor for outputting the ethylene gas separated from the separation tank to the system or returning the ethylene gas to the ethylene storage tank, and the compressor is provided with a compression controller for controlling the operation power of the compressor to adjust the pressure of each equipment in the system.
9. The intelligent enhancement system for preparing polyethylene based on the solution method according to claim 1, wherein a plurality of heat exchangers are further arranged in the system, the heat exchangers are respectively arranged at designated positions in the system and used for exchanging heat with materials in the system to adjust the operation temperature in the system, and each heat exchanger is provided with a heat exchange controller used for adjusting the temperature of a heat exchange medium to adjust the operation temperature of the system.
10. An intelligent strengthening process for preparing polyethylene based on a solution method is characterized by comprising the following steps:
step 1: before the system operates, introducing nitrogen, enabling the nitrogen to flow along the pipeline and fill the system to replace moisture and oxygen in the system, and after replacement is finished, introducing hydrogen into the material feeding pipeline to continue replacement;
step 2: after the replacement is finished, adding the catalyst, the cocatalyst and the electron donor into the first reactor and the second reactor respectively, conveying the solvent into the first reactor through the feed inlet, and allowing the solvent to flow into the second reactor through the discharge outlet of the first reactor;
and step 3: the system starts to operate, ethylene gas in the ethylene storage tank is respectively conveyed to a first micro-interface generator and a second micro-interface generator, each micro-interface generator can respectively crush the ethylene gas to form micron-sized bubbles, and the micron-sized bubbles are respectively output to a first reactor and a second reactor after being crushed;
and 4, step 4: the micron-sized bubbles are respectively output to a first reactor and a second reactor, the micron-sized bubbles are mixed with a solvent to form a gas-liquid emulsion, the gas-liquid emulsion is subjected to polymerization reaction under the action of a catalyst, a cocatalyst and an electron donor to generate polyethylene, during reaction, a first sensor can detect the reaction temperature and the reaction pressure in the first reactor in real time and transmit the measured data to a transport processor, and a second sensor can detect the reaction temperature and the reaction pressure in the second reactor in real time and transmit the measured data to a cloud processor;
and 5: after the reaction is finished, the second reactor outputs the mixed material containing polyethylene to a flash tank, the flash tank can reduce the pressure of the material, so that the boiling point of the material is reduced, the material is evaporated, in the evaporation process, a flash sensor can detect the temperature and the pressure in the flash tank in real time and transmit the measured data to a cloud processor, and after the evaporation is finished, the flash tank can output the upper-layer material to a light component tower and output the lower-layer material to a desolventizing tank;
step 6: after receiving the material output by the flash tank, the first desolventizing tank separates the solvent in the material, outputs the solvent to the light component tower and outputs the lower-layer material to the second desolventizing tank, and after receiving the material received by the first desolventizing tank, the second desolventizing tank secondarily separates the material, outputs the solvent to the light component tower and outputs the lower-layer polyethylene product to the system;
and 7: after the solvent is conveyed to the light component tower, the light component tower rectifies the solvent, the upper-layer material is output to a separation tank after rectification, the lower-layer material is output to a heavy component tower, the heavy component tower rectifies the material for the second time after the material is conveyed to the heavy component tower, the upper-layer material is output to a first drying tower after rectification, the lower-layer heavy component material is discharged out of the system, a light component sensor can detect the rectification temperature in the light component tower in real time in the rectification process and conveys the measured data to a cloud processor, and a heavy component sensor can detect the rectification temperature in the heavy component tower in real time and convey the measured data to the cloud processor;
and 8: the separation tank separates materials after receiving the materials, the separated materials are output to a system or flow back to the ethylene storage tank by the compressor, the materials on the lower layer are conveyed to the second drying tower to be dried, and flow back to the first reactor after being dried;
and step 9: the first drying tower is used for drying the upper-layer material output by the heavy component tower and refluxing the dried upper-layer material to the first reactor;
step 10: in the operation process of the system, the cloud processor receives detection data transmitted by the sensors, when at least one data exceeds a preset range, the cloud processor searches and screens an optimal solution in the cloud database, sends control signals to one or more of the first controller, the second controller, the compression controller and the heat exchange controller according to the optimal solution, and the controller receiving the control signals can adjust corresponding equipment so as to control designated process parameters in the system.
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| CN113477205A (en) * | 2021-07-14 | 2021-10-08 | 南京延长反应技术研究院有限公司 | Automatic gas-liquid mixing system and method thereof |
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Application publication date: 20210316 |