CN206276186U - A kind of polyolefin tail recovery system - Google Patents
A kind of polyolefin tail recovery system Download PDFInfo
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- CN206276186U CN206276186U CN201621364702.9U CN201621364702U CN206276186U CN 206276186 U CN206276186 U CN 206276186U CN 201621364702 U CN201621364702 U CN 201621364702U CN 206276186 U CN206276186 U CN 206276186U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The utility model discloses a kind of polyolefin tail recovery system, and it includes compression cold separation unit, heavy hydrocarbon separative element, lighter hydrocarbons separative element, nitrogen purification unit and turbine expansion unit successively；Film separation unit is included in nitrogen purification unit；At least include a gas-liquid separation unit in lighter hydrocarbons separative element, after logistics heat exchange in first gas and lighter hydrocarbons separative element that gas-liquid separation unit is obtained heats up, further heated up into heavy hydrocarbon separative element, first gas after intensification enter nitrogen purification unit, the first output gas after UF membrane in nitrogen purification unit sequentially enters heavy hydrocarbon separative element and lighter hydrocarbons separative element and exchanged heat with logistics therein lowers the temperature, and the first output gas after cooling enters turbine expansion unit.Polyolefin tail recovery system of the present utility model can be realized significantly reducing energy consumption, the cooling medium without the need for outside input less than environment temperature, improve the purity and the rate of recovery of nitrogen and hydro carbons, save energy consumption and investment and reduce material consumption.
Description
Technical field
The utility model belongs to chemical industry and petrochemical technology field, and in particular to a kind of polyolefin tail recovery system.
Background technology
In polyolefin production processes, from gas (the commonly referred to as tail of the devices such as reactor, flash tank, degassing cabin discharge
Gas) in contain other gases, hydrocarbon therein such as a large amount of inert gases (such as nitrogen, saturated hydrocarbons) and unreacted olefinic monomer
Class has economic worth very high, and (such as degassing cabin purge gass) also can be recycled after nitrogen is purified.Tradition
Solvent recovery technology from vent gas typically use compression condensation method, it is different using the boiling point of various components, and portion is made by reducing temperature
Divide gas liquefaction and realize separating, energy consumption is higher when the rate of recovery high is required due to the method, invests larger, it is impossible to fully meet
The requirement of people.Therefore, people develop bigger, the in hgher efficiency side of separation factor with film, pressure-variable adsorption as representative successively
Method (such as US6706857, US5769927), these methods generally need and compression condensation method is combined, and its reason is to separate
The product for obtaining is gas phase, and its purity or pressure do not reach the requirement of direct reuse.Additionally, people are real for by temperature reduction
Existing liquefied method has been also carried out improving, and most prominent improvement is that the technology from deep cooling is realized using turbine expansion or throttling expansion
(such as CN201310444283).People it has also been found that effect produced by the various combination mode of various methods is different, i.e., from point
Seen from engineering viewpoint, the design of separation sequence is most important.The rate of recovery, product purity, energy consumption produced by different separation sequences,
Investment may be widely different.Regrettably, prior art is only simply combined to existing various isolation technics, not
Deep exploitation, thus various problems are carried out to optimal separation sequence.
CN200910038599.7 discloses a kind of method that tail gas of polyethylene device is recycled completely, the flow point
It is compression condensation separation, the separation of hydrocarbon UF membrane, pressure-variable adsorption from sequence.But the method cannot separate heavy hydrocarbon and lighter hydrocarbons, and
The hydro carbons concentration for obtaining is not also high；Nitrogen and hydrogen cannot be separated, and be caused when density of hydrogen is higher, and nitrogen cannot be used as degassing
Storehouse purge gass are recycled；Out oozing residual air from pressure-variable adsorption in addition still has pressure higher, and the method is without effectively profit
With causing the method process energy consumption also higher.
CN201310444283 disclose it is a kind of for being produced in olefin polymer in reclaim discharge gas system and method,
The separation sequence of the flow be compression condensation separation, hydrogen UF membrane, from cryogenic separation, the technique refer to enter tail gas with hydrogen film
Row Hydrogen Separation, so as to improve the purity of nitrogen, enables recovery nitrogen to be recycled as degassing cabin purge gass, due to its hydrogen film
Separately positioned while causing hydrogen to pass through film, substantial amounts of hydrocarbon component is also passed through therewith from before cryogenic separation, causes hydro carbons to return
Yield reduction；Follow-up from cryogenic separation in addition, its essence is only that a vapor liquid equilibrium is separated, due to the limit of equilibrium separation temperature
System, causes knockout drum top nitrogen out still to contain a small amount of hydro carbons, it is impossible to process, it is impossible to obtain the nitrogen of higher degree.
US5769927 discloses a kind of olefin recovery process, and the separation sequence of the flow is：Compression condensation is separated, film point
From.The use condition of hydrocarbon membrane module is limited to, the condensation temperature of the technique is (about -30 DEG C) higher, can be by portion by condensation separation
Heavy hydrocarbon is divided to separate, but a large amount of lighter hydrocarbons need to be separated by follow-up hydrocarbon UF membrane operation.And the technique divides hydrocarbon film
From lighter hydrocarbons all return to compressor, the outlet of the flow unique separation of hydrocarbons only have compression condensation to separate in knockout drum at, this
It is very big that the separation sequence of sample sets the gas circulation amount that UF membrane can be caused to return to compressor, and hydro carbons in gas phase before compression condensation
It is very high that content need to accumulate, and the hydro carbons in effluent gas recovery system original feed could all be condensed out herein, compressor
Power consumption is increased dramatically.In addition in the recycle of polyolefin tail, the technique is not separated to heavy hydrocarbon and lighter hydrocarbons, becomes nothing
Method is separately recovered to heavy hydrocarbon and lighter hydrocarbons；Nitrogen and hydrogen are not separated so that nitrogen should not blow as degassing cabin
Sweep nitrogen circulation to use, because the circulative accumulation of hydrogen can bring potential safety hazard to the production run of degassing cabin.
CN201510294040.6 discloses the recovery method that a kind of vapor phase method polyolefin discharges tail-gas, the flow point
From sequence be compression condensation separation, common cryogenic separation, hydrocarbon film and hydrogen UF membrane, from cryogenic separation.The patent it has been proposed that
Addition hydrocarbon UF membrane in separation sequence, but the setting of above-mentioned separation sequence, can cause hydrocarbon membrane separation amount very big, because
After common cryogenic separation sequence, substantial amounts of hydro carbons is still contained in gas phase, compressor tolerance is very big to cause hydrocarbon film to return, and energy consumption is very
Greatly；Secondly because due to the limitation of equilibrium separation temperature, after gas is through hydrocarbon film, hydrogen UF membrane, into cryogenic separation, only more
Under low separation temperature, equipment investment, operation energy consumption in the nitrogen of high-purity, therefore the cryogenic separation sequence can be just obtained all
Can be higher than the cryogenic separation operation in aforementioned patent；The other patent itself also indicated that in common cryogenic separation operation, when
When hydro carbons concentration is not high in tail gas, cold need to be additionally supplemented, regrettably, hydrocarbon content is generally relatively low in polyolefin tail,
Therefore the method needs extra supplement low temperature cold.Membrane module temperature in use condition is limited to, common cryogenic separation temperature can not
It is too low, cause in common cryogenic separation operation hydro carbons yield few, therefore hydrocarbon UF membrane operation Main Function thereafter is
Separating hydrocarbons are rather than purification nitrogen.Although after hydrogen UF membrane operation is arranged on hydrocarbon UF membrane operation, yet with hydrocarbon UF membrane
A certain amount of hydro carbons is still had with per-meate side hydrogen discharge to fire is not kept completely separate in hydro carbons, therefore hydrogen UF membrane operation
Torch, so as to cause the loss of hydro carbons.
US6706857 discloses a kind of recovery method of alkene simple substance, and the separation sequence of the technique is：Cryogenic separation, change
Pressure adsorbing separation, the technique is mainly applies in polyolefin tail field pressure-variable adsorption, and adsorbent is made that
Regulation.But its cryogenic separation operation carries out cryogenic separation using extra cold, and energy consumption is very big, it is clear that uneconomical；According to the patent
Description, it is also play separating hydrocarbons that the setting of its pressure-variable adsorption separation circuit is main, thus its return compressor gas
Amount can be very big, and energy consumption of compressor can increase a lot；Tail gas is without heavy hydrocarbon, and actually current polyolefin in the embodiment of the patent
Technique (including polyethylene and polymarization method for prodcing polyacrylates) much all contains heavy hydrocarbon component, therefore the technique cannot be by heavy hydrocarbon and lighter hydrocarbons point
From；The other technique cannot be by hydrogen and nitrogen separation, so as to obtain purer nitrogen.
US574350 discloses a kind of technique that hydro carbons is reclaimed from polyolefin tail, and the separation sequence of the technique is mainly
Compression condensation separation, oily absorption and separation, cryogenic separation.The essence that oil absorbs is also vapor liquid equilibrium, therefore unless finds a kind of height
Effect absorbent, could effectively absorb the hydro carbons in tail gas, and this high-efficiency absorbent should have two features：One is had to hydro carbons
Good assimilation effect；Two is that the absorbent is in itself volatile-resistant substance.But the patent does not mention this kind of absorbent, and
It is therefore the oily assimilation effect and bad as absorbent using heavy hydrocarbon etc.In cryogenic separation, with aforementioned patent
CN201310444283 is the same, and knockout drum top nitrogen out still contains a small amount of hydro carbons, it is impossible to further treatment, it is impossible to obtain
The nitrogen of higher degree.In addition the technique does not also carry out lock out operation to the hydrogen in nitrogen.
For the problem that prior art is present, the utility model provides a kind of polyolefin tail recovery system.
Utility model content
Polyolefin tail recovery system of the present utility model can reduce the energy consumption of compressor, can effectively improve nitrogen and
The purity and nitrogen and the rate of recovery of hydro carbons of hydro carbons, help to save energy consumption and investment, reduce material consumption.
To achieve the above object, the utility model proposes a kind of polyolefin tail recovery system, wherein, the polyolefin
Exhaust gas recovery system includes successively：Compression cold separation unit, heavy hydrocarbon separative element, lighter hydrocarbons separative element, nitrogen purification unit
With turbine expansion unit；
Film separation unit is included in the nitrogen purification unit；
In the lighter hydrocarbons separative element at least include a gas-liquid separation unit, the gas-liquid separation unit obtain first
After logistics heat exchange in gas and the lighter hydrocarbons separative element heats up, further heated up into the heavy hydrocarbon separative element, heated up
The first gas afterwards enter the nitrogen purification unit, the first output gas after the UF membrane in the nitrogen purification unit
Sequentially enter the heavy hydrocarbon separative element and the lighter hydrocarbons separative element and logistics therein heat exchange cooling, after cooling described the
One output gas enters the turbine expansion unit.
Polyolefin tail recovery system as described above, wherein, the compression cold separation unit, the heavy hydrocarbon separate single
At least one of first, described lighter hydrocarbons separative element, the nitrogen purification unit and turbine expansion unit unit uses outer
Portion's cooling medium is cooled down, and the temperature of the outside cooling medium is greater than or equal to ambient temperature.
Polyolefin tail recovery system as described above, wherein, the compression cold separation unit includes：Compressor and cold
But device, wherein, after tail gas and recycle stock enter the compressor boost jointly, enter back into the cooler and cooled down, institute
The cooling medium for stating cooler is recirculated water or air.
Polyolefin tail recovery system as described above, wherein, the heavy hydrocarbon separative element includes：First multithread stock heat exchange
Device and at least one first knockout drums, wherein, enter described from the first tail gas of the compression cold separation unit output
First multithread stock heat exchanger, after first tail gas is cooled to heavy hydrocarbon separation temperature, into the first gas-liquid described at least one point
Heavy hydrocarbon and the second tail gas are isolated from tank.
Polyolefin tail recovery system as described above, wherein, the first multithread stock heat exchanger is plate-fin, around tubular type
Heat exchanger or combination.
Polyolefin tail recovery system as described above, wherein, the lighter hydrocarbons separative element includes：Second multithread stock heat exchange
Device and at least one second knockout drums, wherein, enter described second from the second tail gas of heavy hydrocarbon separative element output
Multithread stock heat exchanger, after second tail gas is cooled to lighter hydrocarbons separation temperature, into the second knockout drum described at least one
Isolate lighter hydrocarbons.
Polyolefin tail recovery system as described above, wherein, the second multithread stock heat exchanger is plate-fin, around tubular type
Heat exchanger or combination.
Polyolefin tail recovery system as described above, wherein, returned from the second output gas of film separation unit output
It is back to the suction port of compressor compressed in cold separation unit or is back to discharge gas memory, the film separation unit
Including at least one set of hydrocarbon membrane separation assemblies and/or at least one set of hydrogen membrane separation assemblies.
Polyolefin tail recovery system as described above, wherein, the film separation unit includes one group of hydrocarbon membrane separation assemblies
With one group of hydrogen membrane separation assemblies, the first gas sequentially enter the hydrocarbon membrane separation assemblies and the hydrogen membrane separation assemblies or institute
State first gas and sequentially enter the hydrogen membrane separation assemblies and the hydrocarbon membrane separation assemblies.
A kind of polyolefin tail recovery system as described above, wherein, compression cold separation unit and the heavy hydrocarbon
Drying equipment is provided between separative element, wherein after the tail gas enters the compression cold separation unit, the tail gas is advanced
Enter the drier and be dried treatment, enter back into the heavy hydrocarbon separative element.
The utility model is by compression cold separation unit, heavy hydrocarbon separative element, lighter hydrocarbons separative element, nitrogen purification list
Unit and turbine expansion unit reasonable arrangement, it is proposed that optimal unit sequence, so as to significantly reduce energy consumption of compressor, while not
Need outside input less than the cooling medium of environment temperature, the purity and the rate of recovery of nitrogen and hydro carbons are all improved, and save
Energy consumption and investment, and reduce material consumption.
Brief description of the drawings
Accompanying drawing described here is only used for task of explanation, and is not intended to by any way limit disclosed in the utility model
Scope.In addition, shape and proportional sizes of each part in figure etc. are only schematical, it is used to help to reason of the present utility model
Solution, is not the shape and proportional sizes for specifically limiting each part of the utility model.Those skilled in the art is new in this practicality
Under the teaching of type, various possible shapes and proportional sizes can be as the case may be selected to implement the utility model.
Fig. 1 is the structural representation () of polyolefin tail recovery system of the present utility model；
Fig. 2 is the structural representation (two) of polyolefin tail recovery system of the present utility model；
Fig. 3 is the structural representation (three) of polyolefin tail recovery system of the present utility model.
Specific embodiment
With reference to the description of accompanying drawing and the utility model specific embodiment, can clearly understand of the present utility model
Details.But, specific embodiment of the present utility model described here is only used for explaining the purpose of this utility model, without
Can be understood as being to limitation of the present utility model by any way.Under teaching of the present utility model, technical staff is contemplated that
Based on any possible deformation of the present utility model, these are regarded as belonging to scope of the present utility model, below in conjunction with
The utility model is described in further detail for accompanying drawing.
Fig. 1 to Fig. 3 is respectively structural representation (), the polyolefin tail of polyolefin tail recovery system of the present utility model
The structural representation (two) of gas recovery system and the structural representation (three) of polyolefin tail recovery system.
It is that lighter hydrocarbons refer to C in the utility model to need described herein2Hn、C3HnMaterial, heavy hydrocarbon refer to C4+HnDeng material.Such as
Described in Fig. 1 to Fig. 3, a kind of polyolefin tail recovery system, wherein, it includes that compression cold separation unit 1, heavy hydrocarbon is separated successively
Unit 2, lighter hydrocarbons separative element 3, nitrogen purification unit 4 and turbine expansion unit 5, wherein, comprising film point in nitrogen purification unit 4
From unit；At least include a gas-liquid separation unit, the first gas 33 that the gas-liquid separation unit is obtained in lighter hydrocarbons separative element 3
After being heated up with the logistics heat exchange in lighter hydrocarbons separative element 3, further heated up into heavy hydrocarbon separative element 2, the first gas after intensification
Body 33 enters nitrogen purification unit 4, and the first output gas after the UF membrane in nitrogen purification unit 4 sequentially enters heavy hydrocarbon and separates list
Unit 2 and lighter hydrocarbons separative element 3 exchange heat with logistics therein and lower the temperature, and the first output gas after cooling enters turbine expansion unit 5.
Specifically, compression cold separation unit 1 includes：Compressor 12 and cooler 13, tail gas 101 and recycle stock are common
Be pressurized into compressor 12, the outlet pressure of compressor 12 of recommendation is 0.8MPa~2.5MPa, enter back into cooler 13 carry out it is cold
But, in one embodiment, the cooling medium of cooler 13 is recirculated water or air.
Further, after tail gas 101 enters compression cold separation unit 1, tail gas 101 is introduced into drying equipment (in figure not
Drying equipment is shown) treatment is dried, enter back into heavy hydrocarbon separative element 2.The drying effect of drier should ensure that follow-up lighter hydrocarbons
Separative element 3 does not produce ice to block up phenomenon, because at low ambient temperatures, when containing a small amount of water in tail gas 101, equipment can produce ice to block up
Phenomenon, therefore, by increase drier can the stifled phenomenon of anti-stagnant ice generation.
Further, in the utility model, during cooler 13 is by entering back into heavy hydrocarbon separative element 2 after surge tank 14,
To realize to alkene tail gas is smoothly conveyed in heavy hydrocarbon separative element 2, certainly, the outlet end mouthful of surge tank 14 can be reclaimed with heavy hydrocarbon
Device 32 is connected, to realize tentatively reclaiming the purpose of heavy hydrocarbon.In one embodiment, set between cooler 13 and surge tank 14
There is drier (drier not shown in figure), and the drying effect of drier should ensure that follow-up lighter hydrocarbons separative element 3 does not produce ice
Stifled phenomenon, because at low ambient temperatures, when containing a small amount of water in tail gas, equipment can produce ice to block up phenomenon, therefore, it is dry by increasing
Dry device can the stifled phenomenon of anti-stagnant ice generation.
Raw material tail gas 101 is compressed to certain pressure (such as 0.8MPa~2.5MPa) by compressor 12, can use recirculated water
Or air is cooled to slightly above environment temperature (such as 40 DEG C).As raw material tail gas contains a small amount of moisture, then drying device can be set and enters
Row water removal operation, in case the generation of the stifled phenomenon of stagnant ice.
Specifically, heavy hydrocarbon separative element 2 includes：The first multithread stock knockout drum 22 of heat exchanger 21 and at least one first
(first knockout drum 22 is only symbolically shown in figure), wherein, from the first tail of the compression output of cold separation unit 1
Gas 15 enters the first multithread stock heat exchanger 21, after the first tail gas 15 is cooled to heavy hydrocarbon separation temperature, at least one first gas
Liquid knockout drum 22 isolates heavy hydrocarbon, and lighter hydrocarbons separative element is entered into from the second tail gas 23 of the top of the first knockout drum 22 output
In 3, the heavy hydrocarbon isolated from the bottom of the first knockout drum 22 is entered back into after the first multithread stock heat exchanger 21 provides cold
To in heavy hydrocarbon retracting device 32, to realize reclaiming heavy hydrocarbon.
Further, the first multithread stock heat exchanger 21 is plate-fin, wound tube heat exchanger or combination, also may be used certainly
Substituted with multiple ordinary heat exchangers.
Logistics from compression cold separation unit 1 enters the first multithread stock heat exchanger 21, using follow-up turbine expansion
The cold that unit 5 is provided carries out heavy hydrocarbon separation in the second knockout drum 22, and liquid phase returns to the first multithread after throttling flash distillation
Stock heat exchanger 21 provides cold, and separation temperature should be determined according to factors such as the partial pressure of heavy hydrocarbon, boiling point, the rate of recovery, the separation of recommendation
Temperature is -20 DEG C~-70 DEG C.Separating heavy hydrocarbon at this moment can also improve the stifled problem of heavy hydrocarbon ice in follow-up lighter hydrocarbons separative element.
Specifically, lighter hydrocarbons separative element 3 includes：Second multithread stock heat exchanger 31 and few second knockout drum 32
(second knockout drum 32 is only symbolically shown in figure), wherein, from the second tail gas 23 of the output of heavy hydrocarbon separative element 2
Into the second multithread stock heat exchanger 31, after the second tail gas 23 is cooled to lighter hydrocarbons separation temperature, at least one second gas-liquids point
Lighter hydrocarbons are isolated from tank 32.
Further, the second multithread stock heat exchanger 31 is plate-fin, wound tube heat exchanger or combination, also may be used certainly
Substituted with multiple ordinary heat exchangers.
The logistics out of the top of first knockout drum 23 enters the second multithread stock heat exchanger 31, swollen using follow-up turbine
The cold that swollen unit 5 is provided carries out lighter hydrocarbons separation in the second knockout drum 32；Separated in the bottom of second knockout drum 32
The liquid phase for going out returns to the second multithread stock heat exchanger 31 and first multithread stock heat exchanger 21 and provides cold successively after throttling flash distillation, so
The liquid phase is entered into light ends unit 36 afterwards, and so as to realize the recovery of lighter hydrocarbons, the second knockout drum 32 top is out
Gas phase 33 (as first gas 33) is back to the second multithread stock heat exchanger 31 and first multithread stock heat exchanger 21 and is answered successively
Heat operation, so as to realize being risen with the logistics heat exchange in lighter hydrocarbons separative element 3 by the first gas 33 obtained in gas-liquid separation unit
Wen Hou, further heats up into heavy hydrocarbon separative element 2, and the first gas 33 after intensification enter nitrogen purification unit 4.Wherein,
The separation temperature of two knockout drums 32 should determine according to factors such as the partial pressure of lighter hydrocarbons, boiling point, the rate of recovery, the separation temperature of recommendation
It is -90 DEG C~-140 DEG C.
Further, as shown in figure 3, the liquid phase isolated in the second knockout drum 32 sequentially enters the 3rd gas-liquid separation
The knockout drum 162 of tank 161 and the 4th arrives light ends unit 36 again, wherein, from the top of the 3rd knockout drum 161 out gas
Body is back to compressor 12, and the liquid phase that the 3rd knockout drum 161 is isolated is successively through the second multithread stock heat exchanger 31 and first
Entered back into in the 4th knockout drum 162 after multithread stock heat exchanger 21, and the 4th knockout drum 162 top out gas
Body is entered into light ends unit 36, and the liquid that the 4th knockout drum 162 is isolated is back to compressor 12, by this
The set-up mode of sample enough can further improve the purity of the lighter hydrocarbons of recovery.
Specifically, in the utility model, the first output gas 41 after the UF membrane in nitrogen purification unit 4 (can also claim
It is retentate gas 41) the first multithread stock heat exchanger 21 and second multithread stock heat exchanger 31 is sequentially entered, so as to realize the first output
Gas 41 is lowered the temperature with the logistics heat exchange in heavy hydrocarbon separative element 2 and lighter hydrocarbons separative element 3, and the first output gas 41 after cooling enters
Turbine expansion unit 5, the second output gas 42 of the film separation unit output in nitrogen purification unit 4 is back to compression refrigerated separation
The entrance of compressor 11 in unit 1, so as to realize the abundant recycling of gas, in the utility model, film separation unit bag
Include at least one set of hydrocarbon membrane separation assemblies 43 and/or at least one set of hydrogen membrane separation assemblies 44.
In one embodiment, film separation unit includes one group of hydrocarbon membrane separation assemblies 43 and one group of hydrogen membrane separation assemblies
44, first gas 33 sequentially enter hydrocarbon membrane separation assemblies 43 and hydrogen membrane separation assemblies 44, and certain first gas 33 can also be successively
Into hydrogen membrane separation assemblies 44 and hydrocarbon membrane separation assemblies 43, namely the order of hydrocarbon membrane separation assemblies 43 and hydrogen membrane separation assemblies 44 can
With adjust, hydrocarbon membrane separation assemblies 43 preceding or hydrogen membrane separation assemblies 44 before can, be not particularly limited herein.
The inside of hydrocarbon membrane separation assemblies 43 includes hydrocarbon film, wherein, in the utility model, hydrocarbon film is hydrocarbon component infiltration rate
Higher than hydrogen, the film of nitrogen component, rubbery state polymeric membrane, such as organosiloxane family macromolecule film, hydrocarbon component are can select
It is higher than the gases such as hydrogen, nitrogen in the infiltration rate of such material, the inside of hydrogen membrane separation assemblies 44 includes hydrogen film, new in this practicality
In type, hydrogen film is that hydrogen component infiltration rate is higher than nitrogen, the film of hydrocarbon component, can select glassy polymer, such as polyamides
Imines film, Nomex film, PS membrane etc., hydrogen are higher than the gases such as nitrogen, hydro carbons in the infiltration rate of such material.Above-mentioned hydrocarbon
The structure of membrane separation assemblies 43 and hydrogen membrane separation assemblies 44 is spiral membrane module, plate and frame module, hollow-fibre membrane group
Any one in part.
In one embodiment, the infiltration gas 441 of hydrogen membrane separation assemblies 44 is connected with discharge gas memory 10, hydrocarbon film
The infiltration gas 431 of separation assembly 43 can be connected (as shown in Figure 2), or the air inlet with compressor 12 with discharge gas memory 10
End is connected (as shown in Fig. 1 or Fig. 3), wherein, the infiltration gas 431 of hydrocarbon membrane separation assemblies 43 is connected with the gas of discharge gas memory 10
When can reduce the energy consumption of compressor 12, but cause hydro carbons be lost it is appropriate increase, infiltration gas 431 and the compression of hydrocarbon membrane separation assemblies 43
The inlet end of machine 12 is connected, it is possible to decrease hydro carbons is lost, but can suitably increase the energy consumption of compressor 12.When hydrocarbon membrane separation assemblies 43
Infiltration gas 431 in hydrocarbon content it is higher when, the infiltration gas 431 can be connected with compressor 11, when hydrocarbon membrane separation assemblies
When hydrocarbon content in 43 infiltration gas 431 is relatively low, infiltration gas 431 can be connected with discharge gas memory 10, i.e. hydrocarbon film point
Infiltration gas 431 from component 43 can be connected according to actual conditions selection with discharge gas memory 10 or compressor 12
It is logical.
The residual air 432 of oozing of hydrocarbon membrane separation assemblies 43 is entered into hydrogen membrane separation assemblies 44, and oozing for hydrogen membrane separation assemblies 44 is remaining
Gas 442 is the first output gas 41 after the UF membrane in the nitrogen purification unit 4 in the utility model.
First gas 33 after re-heat enter hydrocarbon film separation unit, and the per-meate side gas 431 after hydrocarbon UF membrane (is mainly contained
Hydro carbons) entrance of compressor 12 is back to, the residual air 432 of oozing after hydrocarbon UF membrane enters hydrogen film separation unit, after hydrogen UF membrane
Per-meate side gas 441 is back to discharge gas memory 10, and the residual air 442 (mainly high pure nitrogen) of oozing after hydrogen UF membrane is entered successively
Enter heavy hydrocarbon separative element 2 and lighter hydrocarbons separative element 1 is lowered the temperature.Specifically, in the utility model, oozing residual air 442 and leading to successively
The first multithread stock heat exchanger 21 and second multithread stock heat exchanger 31 is crossed to be lowered the temperature.If the residual air of oozing of hydrocarbon film separation unit enters
Hydrogen film separation unit, then because of the accumulation problem of hydrogen, hydrogen film per-meate side gas need to be drained into outside the system, i.e. per-meate side gas 441
It is back to discharge gas memory 10.
First output gas 41 is back to heavy hydrocarbon separative element 2 and enters turbine expansion after lighter hydrocarbons separative element 3 is lowered the temperature
Turbo-expander 51 in unit 5 is expanded, and the gas after expansion returns to lighter hydrocarbons separative element 3 and heavy hydrocarbon separative element 2 is carried
For low temperature cold, so as to realize making the cold of gas to be fully used, energy consumption is advantageously reduced, then the gas enters nitrogen
In retracting device 6.
Further, in the utility model, compression cold separation unit 1, heavy hydrocarbon separative element 2, lighter hydrocarbons separative element
3rd, at least one of nitrogen purification unit 4 and turbine expansion unit 5 unit are cooled down using outside cooling medium, and outside
The temperature of cooling medium is greater than or equal to ambient temperature, so as to advantageously reduce energy consumption.
In one embodiment, only compression cold separation unit 1 is cooled down using outside cooling medium, other lists
Unit is not cooled down using outside cooling medium.
Certainly, in the utility model, compression cold separation unit 1, heavy hydrocarbon separative element 2, lighter hydrocarbons separative element 3, nitrogen
All units in gas purifier units 4 and turbine expansion unit 5 can not also use outside cooling medium.
Low temperature cold in heavy hydrocarbon separative element of the present utility model and lighter hydrocarbons separative element is entirely from turbine expansion list
Expansion cold in unit 5, only employs the outside cooling medium for being not less than environment temperature in cold separation unit 1 is compressed, and
For other techniques, identical hydro carbons, nitrogen gas purity and the rate of recovery are reached, it is necessary to add outer low temperature cooling medium.
Separation of hydrocarbons is divided into heavy hydrocarbon separative element and lighter hydrocarbons separative element by the utility model, and main purpose is as follows：1st, it is real
The separation of existing heavy hydrocarbon and lighter hydrocarbons；2nd, prevent heavy hydrocarbon ice in lighter hydrocarbons separative element from blocking up.
It should be noted that as heavy hydrocarbons content in tail gas is less, ice will not be produced to block up phenomenon in lighter hydrocarbons separative element, and
Without heavy hydrocarbon and lighter hydrocarbons are separated, then heavy hydrocarbon separative element can be cancelled technique, that is, cancel heavy hydrocarbon separative element of the present utility model
2, wherein, lighter hydrocarbons separative element 3 can be described as separation of hydrocarbons unit.
It should be further stated that, the technique shown in Fig. 2 is：The infiltration gas 431 of hydrocarbon film is immediately discharged to outside the system, no
Compressor 11 is returned, the energy consumption of compressor 11 can be so reduced, hydro carbons loss can suitably increase.Technique shown in Fig. 3 is：Second
The bottom of knockout drum 32 liquid phase out enters the 3rd knockout drum 161 after being throttled through choke valve 160 (or be flash distillation
Tank) gas-liquid separation is carried out, gas phase returns to compressor 11；Liquid phase is successively through the second multithread stock heat exchanger 31 and first multithread stock heat exchange
Device 21 carries out further gas-liquid separation after exchanging heat into the 4th knockout drum 162, and the top of the 4th knockout drum 162 goes out
Carry out gas to enter into light ends unit 36, the liquid that the 4th knockout drum 162 is isolated is back to compressor 11, lead to
Crossing such set-up mode enough can further improve the purity of lighter hydrocarbons of recovery.
Recycle stock herein refer in heavy hydrocarbon separative element 2, lighter hydrocarbons separative element 3 and nitrogen purification unit 4 again
It is back to the material of compressor 12.
In Fig. 1 to Fig. 3, in the first multithread stock heat exchanger 21 and second multithread stock heat exchanger 31, material is from left to right
Process is temperature-fall period, and material process from right to left is temperature-rise period.The gas phase that knockout drum herein is isolated goes out
Mouth is located at the top of knockout drum, and the liquid-phase outlet that knockout drum is isolated is located at the bottom of knockout drum.
Polyolefin tail recovery system of the present utility model is applied in an actual field, and with recovery system before
Contrasted.
Embodiment one
Exhaust temperature after certain petroleum chemical enterprise's polyethylene device high pressure lime set tank：- 10 DEG C, pressure：1.2MPaG, because the tail
Gas has had certain pressure, no longer sets up compressor.Using the technological process of accompanying drawing 3, in order to illustrate the weight of separation sequence
The property wanted, comparative example uses the technique of CN201310444283, and its separative element can be summarized as compression cold separation unit, hydrogen film point
From unit, heavy hydrocarbon separative element, lighter hydrocarbons separative element technique.The result of comparative example and embodiment is as shown in table 1.
The result of comparative example and embodiment is contrasted, comparative analysis result is as shown in table 2.
The comparative example of table 1 and the result of embodiment one
The comparing result of table 2
| Title | Lighter hydrocarbons purity (%) | Hydrocarbon recovery (%) | Nitrogen gas purity (%) | Rate of recovery of nitrogen (%) | Discharge throughput (kg/h) |
| Comparative example | 91.73 | 98.36 | 88.72 | 90.26 | 215.07 |
| Embodiment | 98.56 | 99.88 | 97.89 | 90.91 | 174.65 |
The present embodiment is the recovery of polyethylene tail gas, as can be seen from Table 2, in the case where energy consumption is not increased, this implementation
All indexs of example are superior to comparative example, particularly nitrogen gas purity and lighter hydrocarbons purity is far above comparative example.Thus difference is illustrated
Separation sequence can cause completely different separating effect.
Embodiment two
Certain enterprise's polypropylene tail gas enters temperature before compressor：42 DEG C, pressure：1.16barA, using the technique stream of accompanying drawing 3
Journey, still using the technique of CN201310444283, its separation sequence is compression refrigerated separation, hydrogen UF membrane, heavy hydrocarbon point to comparative example
From the technique that, lighter hydrocarbons are separate, the technique will such as obtain high-purity nitrogen, it is necessary to use lower temperature, no matter from investment, energy
All it is inappropriate in consumption or from hydro carbons purity, rate of recovery of nitrogen, therefore the present embodiment and comparative example are ensureing compression
Contrasted on the premise of function consumption is consistent, as shown in table 3, embodiment result is as shown in table 4 for comparative example result.
The result of table 3 and table 4 is contrasted, comparing result is as shown in table 5.
The comparative example result of table 3
The result of 4 embodiment of table two
The comparing result of table 5
| Title | Lighter hydrocarbons purity (wt%) | Hydrocarbon recovery (wt%) | Nitrogen gas purity (wt%) | Rate of recovery of nitrogen (wt%) | Discharge throughput (kg/h) |
| Comparative example | 99.28 | 94.37 | 98.84 | 89.3 | 248 |
| Embodiment | 99.41 | 99.86 | 99.5 | 90 | 230 |
In the case where energy consumption of compressor is consistent, the embodiment of this technique, all indexs are superior to comparative example, particularly hydrocarbon
The class rate of recovery and nitrogen gas purity the two indexs are enhanced.
Embodiment three
Certain enterprise's polypropylene tail gas enters temperature before compressor：40 DEG C, pressure：1.2barA, the comparative example of the present embodiment is adopted
With the technique of US5769927, for the ease of contrast, hydrogen UF membrane is increased on the Process ba- sis, separation sequence is cooled down for compression
Separation, hydrocarbon film, the separation sequence of hydrogen UF membrane, the present embodiment and comparative example are obtaining the High Purity Nitrogen that nitrogen gas purity is 99.5%
Used as comparison condition, comparative example and embodiment result are as shown in table 6.
The comparative example of table 6 and the result of embodiment three
The energy consumption comparison result of table 7
| Compressor power consumption (kw) | Condenser power consumption (kw) | Remarks | |
| Comparative example | 1754 | 1930 | Condenser need to be using ice maker refrigeration to -30 DEG C |
| Embodiment | 900 | 901 | Only it is cooled with circulating water to 40 DEG C |
As can be seen from the above table, the nitrogen that purity is 99.5% is similarly obtained, it is compression refrigerated separation to use separation sequence
Unit, hydrocarbon UF membrane, the comparative example of hydrogen UF membrane, its compressor inlet flow and outlet pressure will be higher than embodiment 1, therefore
Its compressor power consumption power consumption is far longer than embodiment 1, and comparative example need to use extra low-temperature receiver by tail gas condensing after compression to -30
DEG C or so hydro carbons could be reclaimed, for the recirculated water of embodiment 1, many energy consumptions are increased again, in addition comparative example
Heavy hydrocarbon and lighter hydrocarbons are not separated.
Can be seen that polyolefin tail recovery system of the present utility model from above three embodiment can realize significantly drop
The purity and nitrogen of low energy consumption of compressor, the cooling medium without the need for outside input less than environment temperature, nitrogen and hydro carbons
The rate of recovery of gas and hydro carbons is all improved, and is saved energy consumption and investment and is reduced the advantage of material consumption.
Low temperature cold in heavy hydrocarbon separative element 2 of the present utility model and lighter hydrocarbons separative element 3 is entirely from turbine expansion
Expansion cold in unit 5, only employs the outside cooling medium for being not less than environment temperature in cold separation unit 1 is compressed,
And for other techniques, to reach identical hydro carbons, nitrogen gas purity and the rate of recovery, it is necessary to add outer low temperature to cool down and be situated between
Matter.
Separation of hydrocarbons is divided into heavy hydrocarbon separative element and lighter hydrocarbons separative element by the utility model, and main purpose is as follows：1st, it is real
The separation of existing heavy hydrocarbon and lighter hydrocarbons；2nd, prevent heavy hydrocarbon ice in lighter hydrocarbons separative element from blocking up.
The utility model is by compression cold separation unit, hydrocarbon separative element and nitrogen purification unit, turbine expansion list
First reasonable arrangement, it is proposed that optimal separation sequence, so that realize significantly reducing energy consumption of compressor, without the need for outside input
Less than the cooling medium of environment temperature, the rate of recovery of the purity and nitrogen and hydro carbons of nitrogen and hydro carbons is all improved, and saves energy
Consume and invest and reduce material consumption.
Although being described to the utility model by reference to preferred embodiment, model of the present utility model is not being departed from
In the case of enclosing, various improvement can be carried out to it and part therein can be replaced with equivalent.Especially, as long as not depositing
The every technical characteristic being previously mentioned in structural hazard, each embodiment can combine in any way.The utility model
It is not limited to specific embodiment disclosed herein, but all technical schemes including falling within the scope of the appended claims.
Claims (10)
1. a kind of polyolefin tail recovery system, it is characterised in that it is single that it includes that compression cold separation unit, heavy hydrocarbon are separated successively
Unit, lighter hydrocarbons separative element, nitrogen purification unit and turbine expansion unit；
Film separation unit is included in the nitrogen purification unit；
At least include a gas-liquid separation unit, the first gas that the gas-liquid separation unit is obtained in the lighter hydrocarbons separative element
After being heated up with the logistics heat exchange in the lighter hydrocarbons separative element, further heated up into the heavy hydrocarbon separative element, after intensification
The first gas enter the nitrogen purification unit, and the first output gas after the UF membrane in the nitrogen purification unit is successively
Exchanged heat with logistics therein into the heavy hydrocarbon separative element and the lighter hydrocarbons separative element and lowered the temperature, described first after cooling is defeated
Go out gas into the turbine expansion unit.
2. polyolefin tail recovery system as claimed in claim 1, it is characterised in that the compression cold separation unit, institute
State at least in heavy hydrocarbon separative element, the lighter hydrocarbons separative element, the nitrogen purification unit and the turbine expansion unit
Individual unit is cooled down using outside cooling medium, and the temperature of the outside cooling medium is greater than or equal to ambient temperature.
3. polyolefin tail recovery system as claimed in claim 1, it is characterised in that the compression cold separation unit bag
Include：Compressor and cooler, wherein, after tail gas and recycle stock enter the compressor boost jointly, enter back into the cooling
Device is cooled down, and the cooling medium of the cooler is recirculated water or air.
4. polyolefin tail recovery system as claimed in claim 1, it is characterised in that the heavy hydrocarbon separative element includes：The
One multithread stock heat exchanger and at least one first knockout drums, wherein, from the first of the compression cold separation unit output
Tail gas enters first multithread stock heat exchanger, after first tail gas is cooled to heavy hydrocarbon separation temperature, at least one institute
State the first knockout drum and isolate heavy hydrocarbon and the second tail gas.
5. polyolefin tail recovery system as claimed in claim 4, it is characterised in that the first multithread stock heat exchanger is plate
Wing formula, wound tube heat exchanger or combination.
6. polyolefin tail recovery system as claimed in claim 1, it is characterised in that the lighter hydrocarbons separative element includes：The
Two multithread stock heat exchanger and at least one second knockout drums, wherein, from the second tail gas of heavy hydrocarbon separative element output
Into second multithread stock heat exchanger, after second tail gas is cooled to lighter hydrocarbons separation temperature, into described at least one the
Two knockout drums isolate lighter hydrocarbons.
7. polyolefin tail recovery system as claimed in claim 6, it is characterised in that the second multithread stock heat exchanger is plate
Wing formula, wound tube heat exchanger or combination.
8. polyolefin tail recovery system as claimed in claim 3, it is characterised in that from the of film separation unit output
The suction port of compressor or be back to discharge gas memory that two output gas are back in the compression cold separation unit, it is described
Film separation unit includes at least one set of hydrocarbon membrane separation assemblies and/or at least one set of hydrogen membrane separation assemblies.
9. polyolefin tail recovery system as claimed in claim 8, it is characterised in that the film separation unit includes one group of hydrocarbon
Membrane separation assemblies and one group of hydrogen membrane separation assemblies, the first gas sequentially enter the hydrocarbon membrane separation assemblies and the hydrogen film point
The hydrogen membrane separation assemblies and the hydrocarbon membrane separation assemblies are sequentially entered from component or the first gas.
10. a kind of polyolefin tail recovery system as claimed in claim 1, it is characterised in that the compression refrigerated separation list
Drying equipment is provided between first and described heavy hydrocarbon separative element, wherein after the tail gas enters the compression cold separation unit,
The tail gas is introduced into the drier and is dried treatment, enters back into the heavy hydrocarbon separative element.
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| CN201621364702.9U CN206276186U (en) | 2016-12-13 | 2016-12-13 | A kind of polyolefin tail recovery system |
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| CN201621364702.9U CN206276186U (en) | 2016-12-13 | 2016-12-13 | A kind of polyolefin tail recovery system |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107551818A (en) * | 2017-09-18 | 2018-01-09 | 中国科学院理化技术研究所 | Methanol purge gas pressure energy recovery system and method |
| WO2018107553A1 (en) * | 2016-12-13 | 2018-06-21 | 大连欧科膜技术工程有限公司 | Method for recycling polyolefin tail gas |
| CN109579434A (en) * | 2018-12-11 | 2019-04-05 | 浙江大学 | A method of gas is discharged using outer circulation gas wave refrigeration recycling polyolefin device |
| WO2019178741A1 (en) * | 2018-03-20 | 2019-09-26 | 大连欧科膜技术工程有限公司 | System and method for recovering polyolefin exhaust gas |
| WO2023131052A1 (en) * | 2022-01-05 | 2023-07-13 | 隆基绿能科技股份有限公司 | Tail gas recovery system |
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2016
- 2016-12-13 CN CN201621364702.9U patent/CN206276186U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018107553A1 (en) * | 2016-12-13 | 2018-06-21 | 大连欧科膜技术工程有限公司 | Method for recycling polyolefin tail gas |
| US10456728B2 (en) | 2016-12-13 | 2019-10-29 | Dalian Eurofilm Industrial Ltd. | Process for recovering valuables from vent gas in polyolefin production |
| CN107551818A (en) * | 2017-09-18 | 2018-01-09 | 中国科学院理化技术研究所 | Methanol purge gas pressure energy recovery system and method |
| CN107551818B (en) * | 2017-09-18 | 2024-05-17 | 中国科学院理化技术研究所 | Methanol purge gas pressure energy recovery system and method |
| WO2019178741A1 (en) * | 2018-03-20 | 2019-09-26 | 大连欧科膜技术工程有限公司 | System and method for recovering polyolefin exhaust gas |
| CN109579434A (en) * | 2018-12-11 | 2019-04-05 | 浙江大学 | A method of gas is discharged using outer circulation gas wave refrigeration recycling polyolefin device |
| WO2023131052A1 (en) * | 2022-01-05 | 2023-07-13 | 隆基绿能科技股份有限公司 | Tail gas recovery system |
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Inventor after: Du Guodong Inventor after: Ma Yanxun Inventor after: Zhou Xiaobo Inventor before: Du Guodong Inventor before: Ma Yanxun Inventor before: Zhou Xiaobo Inventor before: Bao Chonglong |
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Granted publication date: 20170627 Termination date: 20191213 |