CN101302135B - Method for separating isoprene by front-end hydrogenation one-stage extraction - Google Patents
Method for separating isoprene by front-end hydrogenation one-stage extraction Download PDFInfo
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Abstract
The invention discloses a method for separating isoprene by front-end hydrogenation one-section extraction, which belongs to the C5 fraction separation technical field. The invention aims to solve the problems that: during the prior C5 separation flow, a second extraction unit has high energy consumption, complicated operation and strict operation requirement, and large loss of extracting solvent and so on, and provides a method for separating isoprene fractions by one-section extraction rectification. The method removes cyclopentadiene by a rectification method and removes acetylene hydrocarbon by an azeotropic rectification method, can obtain a polymerization grade isoprene product without secondary extraction, and save the second extraction unit and a solvent refining column. The method has simple and easy operation, and reduces production cost. Under the same raw material treatment load, the heat energy consumption of a polymerization grade isoprene unit is about 20 percent of the prior second extraction unit, m-pentadien is extracted from a pre-deheavy fractionator without entering an extraction rectification unit, the treatment capacity of an extraction rectification column, an absorption tower and a de-heavy fractionator is reduced by 50 percent, and the energy consumption is correspondingly reduced by 50 percent, so the construction cost and the production cost are greatly reduced.
Description
Technical field
The present invention relates to the isolating method of a kind of C5 fraction, more particularly, the present invention relates to the method that a kind of separating cracked carbon-5 fraction is produced the polymerization grade isoprene product.
Background technology
Diolefins such as isoprene, cyclopentadiene and m-pentadiene are rich in a considerable amount of C5 fractions of by-product in the C5 fraction in the process of petroleum cracking system ethene.These diolefin chemical property are active, are important chemical material.Because petroleum hydrocarbon cracking raw materials, cracking severity and separation degree is different, diolefin content is different in the cracked C 5 fraction, and total content is between 40～60%.Therefore, separate and utilize C5 fraction to improving the economic benefit of ethylene unit, the comprehensive utilization petroleum resources have far reaching significance.
Cracked C 5 fraction contain more than 20 kind of boiling point close, easily form the component of azeotrope each other, from wherein isolating the higher C 5 diene of comprehensive utilization value, technology is comparatively complicated.C5 fraction contains for example alkynes such as crotonylene and valylene, these alkynes content are generally in 0.1～2% scope, because their chemical property is active, it is the main detrimental impurity of reaction of C 5 diene product and polymerization process, therefore remove alkynes wherein effectively, this step is the important step of cracked C 5 fraction separating technology.
In order to produce the polymerization grade isoprene product, generally adopt the two-section extraction rectificating method in the prior art, the existing employed extraction solvent of industrialized cracked C 5 fraction method has dimethyl formamide (DMF), acetonitrile etc.For example in carbon five separation process of Beijing Chemical Research Institute's exploitation, first extraction cells removes alkane and the monoolefine in the cracked C 5 fraction, make chemical grade isoprene, second extraction cells removes alkynes and cyclopentadiene wherein, alkynes mainly is crotonylene and valylene, but second extraction cells exists problems, (1) in such two-section extraction rectificating method, operating equipment is more, the energy consumption of second extraction cells is very high, needs strict operation, and the simmer down to operation in some equipment of (2) alkynes brings unsafe factor, there is black bits latch up phenomenon in (3) second extraction cells, solvent recovery unit has a large amount of burnt matter, and is difficult to cleaning, and (4) solvent-oil ratio is big, increase production cost, had problem of environmental pollution simultaneously.
Summary of the invention
The present invention is directed to that existing second extraction cells is taken off the energy consumption height of existence, operational difficulty, easily stopped up, solvent loss is big and uneasy congruent problem, a kind of method of one-section abstraction distillation separation cracking carbon 5-cut fraction is proposed, this method is utilized rectificating method to remove cyclopentadiene and is utilized the azeotropic distillation method to remove alkynes, does not need second extraction cells just can obtain the polymerization grade isoprene product.
Concrete technical scheme is as follows.
The method of the separating isoprene by front-end hydrogenation one-stage extraction that the present invention proposes may further comprise the steps:
(1) pretreatment unit: cracked C 5 fraction enters dipolymer reactor and carries out dimerization reaction, make cyclopentadiene dimerization wherein become dicyclopentadiene, enter pre-weight-removing column then, from the material of cat head extraction based on isoprene, from the material of tower still extraction based on m-pentadiene and dicyclopentadiene, the cat head material with enter azeotropy rectification column based on the C 5 alkane of iso-pentane, from removed overhead carbon containing four, the light constituent of alkynes and alkane, make material from the tower still contain alkynes less than 25ppm, enter hydrogenator from the light constituent of azeotropic distillation cat head and carry out complete hydrogenation, enter knockout drum then, the liquid portion of telling recycles, perhaps the liquid from knockout drum enters the isopentane separation tower, and cat head extraction iso-pentane recycles, tower still extraction Skellysolve A; Material from the azeotropy rectification column still enters the extracting rectifying unit;
(2) extracting rectifying unit: the material from the azeotropy rectification column still enters extractive distillation column from the middle part, extraction solvent enters extractive distillation column from top, through the extracting rectifying effect from cat head extraction C 5 alkane and monoolefine, the solvent that contains isoprene, alkynes and cyclopentadiene is from the extraction of tower still, the solvent of this hydrocarbonaceous enters Analytic Tower, from resolving cat head extraction isoprene, alkynes and cyclopentadiene, use from the solvent cycle of Analytic Tower still extraction
Perhaps enter first Analytic Tower and resolve the recovery solvent from the solvent of the hydrocarbonaceous of extractive distillation column still, first Analytic Tower and the second Analytic Tower serial operation, first gas of resolving the cat head extraction enters the bottom of second Analytic Tower, the liquid of the second Analytic Tower still enters from the first Analytic Tower cat head, from the second parsing cat head extraction isoprene, alkynes and cyclopentadiene, use from the solvent cycle of the first Analytic Tower still extraction; Enter the bottom of weight-removing column from resolving the cat head or second material of resolving cat head,, make cyclopentadiene content in the isoprene less than 1ppm, tower still extraction cyclopentadiene and the isoprene of carrying secretly from cat head extraction isoprene.
In the present invention, the boiling point of isoprene and valylene (valylene) is 34 ℃, adopts the conventional distillation method not separate between them.Yet iso-pentane can form azeotrope with crotonylene and valylene respectively, does not form azeotrope with isoprene, and the boiling point of the azeotrope that iso-pentane and valylene form is 26.3 ℃, and azeotropic consists of the iso-pentane of 63.8 quality %.The boiling point of the azeotrope that iso-pentane and crotonylene form is lower.Thereby utilize iso-pentane can remove alkynes in the isoprene as entrainer.
Preferably, dipolymer reactor being set before weight-removing column makes the cyclopentadiene dimerization in the material become dicyclopentadiene.
Method of the present invention can further include step: merge from the material of pre-weight-removing column tower still with from the material of weight-removing column tower still, send into carbon five and steam tower, steam column overhead extraction carbon five hydrocarbon at carbon five, from tower still extraction dicyclopentadiene, cat head carbon five hydrocarbon enter the m-pentadiene treating tower, from the material of cat head extraction isoprene containing, this material enters dipolymer reactor or the pre-weight-removing column before the pre-weight-removing column, and the tower still obtains the m-pentadiene product.
Alternatively, method of the present invention can further include step: send into carbon five from the material of pre-weight-removing column tower still and steam tower, steam column overhead extraction carbon five hydrocarbon at carbon five, from tower still extraction dicyclopentadiene, cat head carbon five hydrocarbon enter the m-pentadiene treating tower, from the material of cat head extraction isoprene containing, this material and merge dipolymer reactor or the pre-weight-removing column that enters before the pre-weight-removing column from the material of weight-removing column tower still, the tower still obtains the m-pentadiene product.
In the present invention, there is no particular limitation for Rectification Column's Theoretical Plate Number and concrete operations condition, those skilled in the art can select suitable number of theoretical plate and operational condition by calculating according to practical situation, can be by changing the purpose of separating that number of theoretical plate, feed rate and backflow recently reach each tower.For the reaction conditions of reactor, those skilled in the art can carry out suitable selection with reference to prior art.
Preferably, pre-weight-removing column has 70～130 number of theoretical plates, and reflux ratio is 5～20, and tower top temperature is 40～60 ℃, from the middle part charging.
Preferably, weight-removing column has 70～150 number of theoretical plates, and reflux ratio is 7～20, and tower top temperature is 40～60 ℃, from underfeed.
Preferably, described azeotropy rectification column has 70～200 theoretical stages, and from tower middle part charging, the weight ratio of isoprene material and iso-pentane is 20: 0.5～5, and reflux ratio is 50～120.
Palladium-based catalyst or nickel-base catalyst are housed in hydrogenator, and reaction conditions is: reaction pressure 1.0～5.0MPa, 20～150 ℃ of temperature of reaction, liquid hourly space velocity 0.1～10h
-1Owing to contain a large amount of iso-pentane and a spot of alkynes, monoolefine from the material of azeotropic distillation cat head, the purpose of carrying out shortening in this hydrogenator is exactly the alkynes hydrogenation and removing with wherein, this hydrogenation reaction is complete hydrogenation reaction, the unsaturated hydrocarbons that will comprise alkynes is hydrogenated into alkane fully, therefore can use industrial normally used hydrogenation with palladium-based catalyst or nickel-base catalyst, for example the various hydrogenation catalysts produced of Beijing Chemical Research Institute.There is no particular limitation to hydrogenation conditions, those skilled in the art can freely select according to general knowledge, crotonylene hydrogenation in the material of azeotropic distillation cat head extraction becomes butane, the also complete hydrogenation of carbon four that contains and C 5 monoolefin becomes alkane, normal olefine is hydrogenated to Skellysolve A, and isomeric olefine, valylene and isoprene are hydrogenated into iso-pentane.Therefore, material from the azeotropic distillation column overhead mainly generates iso-pentane and Skellysolve A through hydrogenation, iso-pentane accounts for major part, Skellysolve A accounts for small part, this material loops back azeotropy rectification column, iso-pentane is as the entrainer of alkynes, Skellysolve A is told from cat head on a small quantity, major part enters extraction tower with isoprene, flow out from the extraction tower cat head, thereby can recycle from the liquid material of hydrogenator, internal circulating load depends on the needs, the remainder extraction can be used as solvent or simply blends into cooling agent.Also can as required iso-pentane and Skellysolve A be separated.
In separation method of the present invention, any solvent that extractive distillation column can use this area to use for example uses acetonitrile, dimethyl formamide or N-Methyl pyrrolidone as solvent.
Highly purified isoprene is when being used for polyreaction, a spot of alkynes can consume polymerizing catalyst in large quantities, and bring disadvantageous color to polymerisate, therefore the general requirement alkynes that is used for the polymeric high purity isoprene less than 50ppm and cyclopentadiene less than 1ppm, adopt separation method of the present invention, do not need to carry out second section extraction and just can obtain the polymerization grade isoprene product.In the present invention, concentration all in mass, per-cent is meant mass percent, ppm is meant * 10
-6(mass concentration).
Method of the present invention is compared with existing C5 fraction separation process, has the following advantages:
1. the method for separating isoprene by front-end hydrogenation one-stage extraction of the present invention only adopts the one-section abstraction rectificating method, not needing for the second time, extraction rectifying method just can obtain the polymerization grade isoprene product, because do not have the second extracting rectifying unit, thereby can omit the solvent treatment tower.The purpose of solvent treatment tower is exactly the dicyclopentadiene that removes in the circulating solvent, avoid making the cyclopentadiene content in the isoprene product be higher than 1ppm during extracting rectifying in the second time, obviously, there is not such problem in method of the present invention, does not just need the solvent treatment tower.
2. the equipment that method of the present invention is used is few, simple to operate, easy handling, and construction cost and production cost reduce.The cracking c_5 raw material is not to take off in advance gently according to original technology, but directly carry out dimerization reaction, take off components such as heavily removing dicyclopentadiene and m-pentadiene through pre-weight-removing column, make the mass flow that enters azeotropy rectification column reduce, the azeotropy rectification column removed overhead comprises the light constituent of alkynes, that is to say the azeotropy rectification column use or transform original pre-lightness-removing column, do not need additionally to increase rectifying tower like this.
3. handle under the load at identical raw material, in polymerization grade isoprene of the present invention unit the needed heat energy consumption of azeotropic distillation part be about existing second extraction cells the heat energy consumption 20%.Because m-pentadiene from the extraction of pre-weight-removing column tower still, does not enter the extracting rectifying unit, the treatment capacity of extractive distillation column, Analytic Tower and weight-removing column reduces by 50%, and correspondingly energy consumption also reduces by 50%, and therefore, production cost reduces greatly.
4. one-section abstraction method separating cracked carbon five of the present invention can be produced the pentane product simultaneously, and this pentane product can be used as solvent or simply blends into cooling agent, is the existing advantage that is not had of separating.
Description of drawings
Fig. 1 is the synoptic diagram of the existing cracked C 5 fraction separation process of China.
Fig. 2 is the schematic flow sheet of a scheme of the method for separating isoprene by front-end hydrogenation one-stage extraction of the present invention.
Fig. 3 is the schematic flow sheet of another scheme of the method for separating isoprene by front-end hydrogenation one-stage extraction of the present invention.
Nomenclature:
In Fig. 1, the pre-lightness-removing column of T-101; The R-101 dipolymer reactor; The pre-weight-removing column of T-102; T-201 first extraction tower; T-202, T-203 one collection Analytic Tower; The T-204 weight-removing column; T-301 second extraction tower; The T-302 lightness-removing column; T-303 two collection Analytic Towers; T-304 vacuum analysis tower; T-401 carbon five steams tower; T-402 m-pentadiene treating tower; T-403 dicyclopentadiene treating tower; The E-501 solvent regeneration tower; The burnt matter dilution of V-501 tower; T-501 solvent treatment tower;
In Fig. 2,1 azeotropy rectification column; The R-1 hydrogenator; The V-1 knockout drum, 2 isopentane separation towers, all the other are identical with symbol implication among Fig. 1.
Embodiment
Method below in conjunction with the further separating isoprene by front-end hydrogenation one-stage extraction of the present invention of accompanying drawing.
With reference to Fig. 1, C5 fraction separation method by Beijing Chemical Research Institute's research has the commerical test device in Kingsoft construction, adopt the two-section extraction rectificating method, comprise 5 unit altogether, i.e. raw materials pretreatment unit, first extraction cells, second extraction cells, m-pentadiene and dicyclo refined unit and solvent recovery unit.The raw materials pretreatment unit removes most of alkynes and light constituent in pre-lightness-removing column T-101, through dipolymer reactor R-101 cyclopentadiene is transformed into dicyclopentadiene, removes in pre-weight-removing column T-102.In first extraction cells, the first extraction tower T-201 adopts solvent removal alkane and monoolefine, the solvent that contains isoprene is resolved the recovery solvent through a collection Analytic Tower T-202 and T-203, the material that parses contains components such as isoprene, alkynes (being mainly crotonylene, valylene), m-pentadiene, a small amount of cyclopentadiene, cyclopentenes, pentamethylene, isolates isoprene, alkynes, micro-cyclopentadiene through weight-removing column T-204 from cat head.In second extraction cells, utilize solvent in the second extraction tower T-301, valylene and cyclopentadiene to be extracted in the solvent once more, cat head is isolated isoprene and crotonylene, this material enters lightness-removing column T-302 general crotonylene (isoprene: 34 ℃ wherein, crotonylene: 27 ℃) isolate, solvent reclaims solvent through normal pressure Analytic Tower T-303 and decompression Analytic Tower T-304.M-pentadiene and dicyclo refined unit obtain m-pentadiene product and dicyclo product through decarburization five tower T-401, m-pentadiene treating tower T-402 and dicyclo treating tower T-403.Solvent recovery unit at first utilizes regeneration still E-501 to remove wherein burnt matter, burnt matter is emitted through dilution in V-501, utilize water and dicyclo azeotropic to steam wherein dicyclo at solvent treatment tower T-501 then, the cyclopentadiene that the recovery solvent of avoiding entering second extraction cells has in the isoprene product that the dicyclo component makes production is defective.
Explain one embodiment of the invention below with reference to Fig. 2.
The method of the separating isoprene by front-end hydrogenation one-stage extraction that the present invention proposes may further comprise the steps:
(1) pretreatment unit: cracked C 5 fraction enters dipolymer reactor R-101 and carries out dimerization reaction, make cyclopentadiene dimerization wherein become dicyclopentadiene, enter pre-weight-removing column T-102 then, from the material of cat head extraction based on isoprene, from the material of tower still extraction based on m-pentadiene and dicyclopentadiene, cat head material and iso-pentane enter azeotropy rectification column 1, from removed overhead carbon containing four, the light constituent of alkynes and alkane, make material from the tower still contain alkynes less than 25ppm, enter hydrogenator R-1 from the light constituent on azeotropy rectification column 1 top and carry out complete hydrogenation, enter knockout drum V-1 then, the liquid portion of telling recycles, and enters the extracting rectifying unit from the material of azeotropy rectification column still;
(2) extracting rectifying unit: the material from azeotropy rectification column 1 still enters extractive distillation column T-201 from the middle part, extraction solvent enters extractive distillation column T-201 from top, through the extracting rectifying effect from cat head extraction C 5 alkane and monoolefine, contain isoprene, the solvent of alkynes and cyclopentadiene is from the extraction of tower still, the solvent of this hydrocarbonaceous enters the first Analytic Tower T-202 and resolves the recovery solvent, the first Analytic Tower T-202 and the second Analytic Tower T-203 serial operation, the gas of the first Analytic Tower T-202 top extraction enters the bottom of the second Analytic Tower T-203, the liquid of the second Analytic Tower T-203 still enters from the first Analytic Tower T-202 cat head, from the second Analytic Tower T-203 top extraction isoprene, alkynes and cyclopentadiene, use from the solvent cycle of the first Analytic Tower T-202 still extraction, regenerate from the second Analytic Tower T-203 tower still extraction a small amount of solvent regeneration unit that desolvates; Enter the bottom of weight-removing column T-204 from the material of resolving the cat head or second Analytic Tower T-203 top,, make cyclopentadiene content in the isoprene less than 1ppm, tower still extraction cyclopentadiene and the isoprene of carrying secretly from cat head extraction isoprene.
Method of the present invention may further include step: merge from the material of pre-weight-removing column T-102 tower still with from the material of weight-removing column 2 tower stills, send into carbon five and steam tower T-401, steam tower T-401 cat head extraction carbon five hydrocarbon at carbon five, from tower still extraction dicyclopentadiene, cat head carbon five hydrocarbon enter m-pentadiene treating tower T-402, material from cat head extraction isoprene containing, this material enters dipolymer reactor R-101 or pre-weight-removing column T-102, can certainly be sent to head tank, the tower still obtains the m-pentadiene product.Perhaps, be sent to dipolymer reactor R-101 or pre-weight-removing column T-102 from the material of weight-removing column 2 tower stills and from the material merging of m-pentadiene treating tower T-402 cat head.These materials that circulate can reclaim wherein isoprene to improve the isoprene yield of whole device, certainly this step that is not absolutely necessary.The material that steams tower T-401 tower still from carbon five enters dicyclopentadiene treating tower T-403, and the tower still obtains the dicyclopentadiene product.This part is identical with China existing cracked C 5 fraction tripping device, does not specifically describe here.Certainly those skilled in the art can be according to practical situation by these three rectifying tower of calculation Design.
Extract partial solvent out from the second Analytic Tower T-203 tower still and be sent to solvent reclamation still E-501, the decompression heating steams solvent, the solvent cycle utilization, and the residue of the solvent reclamation still E-501 solvent cut jar V-501 that fell regularly emits.Solvent reclamation still and regeneration condition are identical with existing regeneration still, and it is just passable to separate burnt matter by underpressure distillation, does not specifically describe here.But compared with prior art, the present invention does not need the solvent treatment tower.
Explain another embodiment of the invention below with reference to Fig. 3.
The method of the front-end hydrogenation one-section abstraction separating cracked carbon five that the present invention proposes may further comprise the steps:
(1) pretreatment unit: cracked C 5 fraction enters dipolymer reactor R-101 and carries out dimerization reaction, make cyclopentadiene dimerization wherein become dicyclopentadiene, enter pre-weight-removing column T-102 then, from the material of cat head extraction based on isoprene, from the material of tower still extraction based on m-pentadiene and dicyclopentadiene, cat head material and iso-pentane enter azeotropy rectification column 1, from removed overhead carbon containing four, the light constituent of alkynes and alkane, make material from the tower still contain alkynes less than 25ppm, enter hydrogenator R-1 from the light constituent on azeotropy rectification column 1 top and carry out complete hydrogenation, enter knockout drum V-1 then, the liquid of telling enters isopentane separation tower 2, cat head extraction iso-pentane, tower still extraction Skellysolve A; Material from azeotropy rectification column 1 still enters the extracting rectifying unit;
(2) extracting rectifying unit: the material from azeotropy rectification column 1 still enters extractive distillation column T-201 from the middle part, extraction solvent enters extractive distillation column T-201 from top, through the extracting rectifying effect from cat head extraction C 5 alkane and monoolefine, contain isoprene, the solvent of alkynes and cyclopentadiene is from the extraction of tower still, the solvent of this hydrocarbonaceous enters the first Analytic Tower T-202 and resolves the recovery solvent, the first Analytic Tower T-202 and the second Analytic Tower T-203 serial operation, the gas of the first Analytic Tower T-202 top extraction enters the bottom of the second Analytic Tower T-203, the liquid of the second Analytic Tower T-203 still enters from the first Analytic Tower T-202 cat head, from the second Analytic Tower T-203 top extraction isoprene, alkynes and cyclopentadiene, use from the solvent cycle of the first Analytic Tower T-202 still extraction, regenerate from the second Analytic Tower T-203 tower still extraction a small amount of solvent regeneration unit that desolvates; Enter the bottom of weight-removing column T-204 from the material of resolving the cat head or second Analytic Tower T-203 top,, make cyclopentadiene content in the isoprene less than 1ppm, tower still extraction cyclopentadiene and the isoprene of carrying secretly from cat head extraction isoprene.
This programme can comprise other selectable step equally.
Cracked C 5 fraction with Yanshan Petrochemical company is a raw material, utilizes separation method of the present invention to carry out cracked C 5 fraction and separates, and raw material is formed and the turnover material of each operating gear is formed and is listed in the table below in 1.
(1) pretreatment unit: 31, the cracked C 5 fraction of 000kg/h enters dipolymer reactor R-101 and carry out dimerization reaction under 80～85 ℃, make cyclopentadiene dimerization wherein become dicyclopentadiene, enter pre-weight-removing column T-102 then, pre-weight-removing column T-102 has 85 theoretical stages, reflux ratio is 10, tower top temperature is 50 ℃, from the material of cat head extraction based on isoprene, from the material of tower still extraction based on m-pentadiene and dicyclopentadiene, cat head material and iso-pentane enter azeotropy rectification column 1, azeotropy rectification column 1 has 100 theoretical stages, reflux ratio is 100, the charging mass flux ratio of iso-pentane and isoprene is 1: 20, tower top temperature is 45 ℃, from removed overhead carbon containing four, the light constituent of alkynes and alkane, make material from the tower still contain alkynes less than 25ppm, enter the hydrogenator R-1 of the palladium catalyst that Beijing Chemical Research Institute's production is housed from the light constituent on azeotropy rectification column 1 top, through shortening with the alkynes hydrogenation and removing, hydrogenation pressure is 3.0Mpa, hydrogenation temperature is 45～60 ℃, and the volume hourly space velocity is 3h
-1, by analysis, the material behind the hydrogenation does not contain alkynes and alkene substantially; The material that comes out from hydrogenator R-1 enters knockout drum V-1, the compressed hydrogenator R-1 that loops back of the hydrogen of telling from knockout drum V-1 upper end uses, the liquid portion that the liquid that the lower end is told is told recycles, and enters the extracting rectifying unit from the material of azeotropy rectification column still;
(2) extracting rectifying unit: the material from azeotropy rectification column 1 still enters extractive distillation column T-201 from the middle part, extractive distillation column T-201 has 110 theoretical stages, reflux ratio is 3, extraction solvent enters extractive distillation column T-201 from top, solvent is a dimethyl formamide in the present embodiment, but the present invention is not limited to it, the charging mass flux ratio of solvent and carbon five hydrocarbon chargings is 5.5, through the extracting rectifying effect from cat head extraction C 5 alkane and monoolefine, contain isoprene, the solvent of alkynes and cyclopentadiene is from the extraction of tower still, the solvent of this hydrocarbonaceous enters the first Analytic Tower T-202 and resolves the recovery solvent, the first Analytic Tower T-202 and the second Analytic Tower T-203 serial operation, the gas of the first Analytic Tower T-202 top extraction enters the bottom of the second Analytic Tower T-203, the liquid of the second Analytic Tower T-203 still enters from the first Analytic Tower T-202 cat head, from the second Analytic Tower T-203 top extraction isoprene, alkynes and cyclopentadiene, use from the solvent cycle of the first Analytic Tower T-202 still extraction, regenerate from the second Analytic Tower T-203 tower still extraction a small amount of solvent regeneration unit that desolvates, the first Analytic Tower T-202 and the second Analytic Tower T-203 have 15 theoretical stages respectively, the reflux ratio of the second Analytic Tower T-203 is 1, and tower top temperature is 50 ℃; Enter the bottom of weight-removing column from the material of resolving the cat head or the second parsing cat head, weight-removing column T-204 has 100 theoretical stages, reflux ratio is 15, tower top temperature is 45 ℃, from cat head extraction isoprene, make cyclopentadiene content in the isoprene less than 1ppm, tower still extraction cyclopentadiene and the isoprene of carrying secretly.
Merge from the material of pre-weight-removing column T-102 tower still with from the material of weight-removing column 2 tower stills, send into carbon five and steam tower T-401, steam tower T-401 cat head extraction carbon five hydrocarbon at carbon five, from tower still extraction dicyclopentadiene, cat head carbon five hydrocarbon enter m-pentadiene treating tower T-402, and from the material of cat head extraction isoprene containing, this material enters dipolymer reactor R-101 or pre-weight-removing column T-102, can certainly be sent to head tank, the tower still obtains the m-pentadiene product.Perhaps, be sent to dipolymer reactor R-101 or pre-weight-removing column T-102 from the material of weight-removing column 2 tower stills and from the material merging of m-pentadiene treating tower T-402 cat head.The material that steams tower T-401 tower still from carbon five enters dicyclopentadiene treating tower T-403, and the tower still obtains the dicyclopentadiene product.This part is identical with China existing cracked C 5 fraction tripping device, does not specifically describe here.Certainly those skilled in the art can be according to practical situation by these three rectifying tower of calculation Design.
Extract partial solvent out from the second Analytic Tower T-203 tower still and be sent to solvent reclamation still E-501, the decompression heating steams solvent, the solvent cycle utilization, and the residue of the solvent reclamation still E-501 solvent cut jar V-501 that fell regularly emits.Solvent reclamation still and regeneration condition are identical with existing regeneration still, and it is just passable to separate burnt matter by underpressure distillation, does not specifically describe here.But compared with prior art, the present invention does not need the solvent treatment tower.
The turnover material of table 1 main device is formed
Embodiment 2
Cracked C 5 fraction with Yanshan Petrochemical company is a raw material, utilizes separation method of the present invention to carry out cracked C 5 fraction and separates, and raw material is formed and the turnover material of each operating gear is formed and is listed in the table below in 2.
(1) pretreatment unit: 31, the cracked C 5 fraction of 000kg/h enters dipolymer reactor R-101 and carry out dimerization reaction under 80～85 ℃, make cyclopentadiene dimerization wherein become dicyclopentadiene, enter pre-weight-removing column T-102 then, pre-weight-removing column T-102 has 85 theoretical stages, reflux ratio is 10, tower top temperature is 50 ℃, from the material of cat head extraction based on isoprene, from the material of tower still extraction based on m-pentadiene and dicyclopentadiene, cat head material and iso-pentane enter azeotropy rectification column 1, azeotropy rectification column 1 has 100 theoretical stages, reflux ratio is 100, the charging mass flux ratio of iso-pentane and isoprene is 1: 20, tower top temperature is 45 ℃, from removed overhead carbon containing four, the light constituent of alkynes and alkane, make material from the tower still contain alkynes less than 25ppm, enter the hydrogenator R-1 of the palladium catalyst that Beijing Chemical Research Institute's production is housed from the light constituent on azeotropy rectification column 1 top, through shortening with the alkynes hydrogenation and removing, hydrogenation pressure is 3.0Mpa, hydrogenation temperature is 45～60 ℃, and the volume hourly space velocity is 3h
-1, by analysis, the material behind the hydrogenation does not contain alkynes and alkene substantially; The material that comes out from hydrogenator R-1 enters knockout drum V-1, the compressed hydrogenator R-1 that loops back of the hydrogen of telling from knockout drum V-1 upper end uses, and the liquid that the lower end is told enters isopentane separation tower 2, isopentane separation tower 2, cat head extraction iso-pentane, tower still extraction Skellysolve A;
(2) extracting rectifying unit: the material from azeotropy rectification column 1 still enters extractive distillation column T-201 from the middle part, extractive distillation column T-201 has 110 theoretical stages, reflux ratio is 3, extraction solvent enters extractive distillation column T-201 from top, solvent is a dimethyl formamide in the present embodiment, but the present invention is not limited to it, the charging mass flux ratio of solvent and carbon five hydrocarbon chargings is 5.5, through the extracting rectifying effect from cat head extraction C 5 alkane and monoolefine, contain isoprene, the solvent of alkynes and cyclopentadiene is from the extraction of tower still, the solvent of this hydrocarbonaceous enters the first Analytic Tower T-202 and resolves the recovery solvent, the first Analytic Tower T-202 and the second Analytic Tower T-203 serial operation, the gas of the first Analytic Tower T-202 top extraction enters the bottom of the second Analytic Tower T-203, the liquid of the second Analytic Tower T-203 still enters from the first Analytic Tower T-202 cat head, from the second Analytic Tower T-203 top extraction isoprene, alkynes and cyclopentadiene, use from the solvent cycle of the first Analytic Tower T-202 still extraction, regenerate from the second Analytic Tower T-203 tower still extraction a small amount of solvent regeneration unit that desolvates, the first Analytic Tower T-202 and the second Analytic Tower T-203 have 15 theoretical stages respectively, the reflux ratio of the second Analytic Tower T-203 is 1, and tower top temperature is 50 ℃; Enter the bottom of weight-removing column from the material of resolving the cat head or the second parsing cat head, weight-removing column T-204 has 100 theoretical stages, reflux ratio is 15, tower top temperature is 45 ℃, from cat head extraction isoprene, make cyclopentadiene content in the isoprene less than 1ppm, tower still extraction cyclopentadiene and the isoprene of carrying secretly.
Merge from the material of pre-weight-removing column T-102 tower still with from the material of weight-removing column 2 tower stills, send into carbon five and steam tower T-401, steam tower T-401 cat head extraction carbon five hydrocarbon at carbon five, from tower still extraction dicyclopentadiene, cat head carbon five hydrocarbon enter m-pentadiene treating tower T-402, and from the material of cat head extraction isoprene containing, this material enters dipolymer reactor R-101 or pre-weight-removing column T-102, can certainly be sent to head tank, the tower still obtains the m-pentadiene product.Perhaps, be sent to dipolymer reactor R-101 or pre-weight-removing column T-102 from the material of weight-removing column 2 tower stills and from the material merging of m-pentadiene treating tower T-402 cat head.The material that steams tower T-401 tower still from carbon five enters dicyclopentadiene treating tower T-403, and the tower still obtains the dicyclopentadiene product.This part is identical with China existing cracked C 5 fraction tripping device, does not specifically describe here.Certainly those skilled in the art can be according to practical situation by these three rectifying tower of calculation Design.
Extract partial solvent out from the second Analytic Tower T-203 tower still and be sent to solvent reclamation still E-501, the decompression heating steams solvent, the solvent cycle utilization, and the residue of the solvent reclamation still E-501 solvent cut jar V-501 that fell regularly emits.Solvent reclamation still and regeneration condition are identical with existing regeneration still, and it is just passable to separate burnt matter by underpressure distillation, does not specifically describe here.But compared with prior art, the present invention does not need the solvent treatment tower.
The turnover material of table 2 main device is formed
Claims (9)
1. the method for a separating isoprene by front-end hydrogenation one-stage extraction is characterized in that, said method comprising the steps of:
(1) pretreatment unit: cracked C 5 fraction enters dipolymer reactor and carries out dimerization reaction, make cyclopentadiene dimerization wherein become dicyclopentadiene, enter pre-weight-removing column then, from the material of cat head extraction based on isoprene, from the material of tower still extraction based on m-pentadiene and dicyclopentadiene, the cat head material with enter azeotropy rectification column based on the C 5 alkane of iso-pentane, from removed overhead carbon containing four, the light constituent of alkynes and alkane, make material from the tower still contain alkynes less than 25ppm, enter hydrogenator from the light constituent of azeotropic distillation cat head and carry out complete hydrogenation, enter knockout drum then, the liquid portion of telling recycles, perhaps the liquid from knockout drum enters the isopentane separation tower, and cat head extraction iso-pentane recycles, tower still extraction Skellysolve A; Material from the azeotropy rectification column still enters the extracting rectifying unit;
(2) extracting rectifying unit: the material from the azeotropy rectification column still enters extractive distillation column from the middle part, extraction solvent enters extractive distillation column from top, through the extracting rectifying effect from cat head extraction C 5 alkane and monoolefine, the solvent that contains isoprene, alkynes and cyclopentadiene is from the extraction of tower still, the solvent of this hydrocarbonaceous enters Analytic Tower, from resolving cat head extraction isoprene, alkynes and cyclopentadiene, use from the solvent cycle of Analytic Tower still extraction
Perhaps enter first Analytic Tower and resolve the recovery solvent from the solvent of the hydrocarbonaceous of extractive distillation column still, first Analytic Tower and the second Analytic Tower serial operation, first gas of resolving the cat head extraction enters the bottom of second Analytic Tower, the liquid of the second Analytic Tower still enters from the first Analytic Tower cat head, from the second parsing cat head extraction isoprene, alkynes and cyclopentadiene, use from the solvent cycle of the first Analytic Tower still extraction; Enter the bottom of weight-removing column from resolving the cat head or second material of resolving cat head,, make cyclopentadiene content in the isoprene less than 1ppm, tower still extraction cyclopentadiene and the isoprene of carrying secretly from cat head extraction isoprene.
2. the method for separating isoprene by front-end hydrogenation one-stage extraction as claimed in claim 1 is characterized in that, dipolymer reactor is set before weight-removing column makes the cyclopentadiene dimerization in the material become dicyclopentadiene.
3. the method for separating isoprene by front-end hydrogenation one-stage extraction as claimed in claim 1 or 2, it is characterized in that, merge from the material of pre-weight-removing column tower still with from the material of weight-removing column tower still, send into carbon five and steam tower, steam column overhead extraction carbon five hydrocarbon, from tower still extraction dicyclopentadiene at carbon five, cat head carbon five hydrocarbon enter the m-pentadiene treating tower, from the material of cat head extraction isoprene containing, this material enters dipolymer reactor or the pre-weight-removing column before the pre-weight-removing column, and the tower still obtains the m-pentadiene product.
4. the method for separating isoprene by front-end hydrogenation one-stage extraction as claimed in claim 1 or 2, it is characterized in that, send into carbon five from the material of pre-weight-removing column tower still and steam tower, steam column overhead extraction carbon five hydrocarbon at carbon five, from tower still extraction dicyclopentadiene, cat head carbon five hydrocarbon enter the m-pentadiene treating tower, from the material of cat head extraction isoprene containing, this material and merge dipolymer reactor or the pre-weight-removing column that enters before the pre-weight-removing column from the material of weight-removing column tower still, the tower still obtains the m-pentadiene product.
5. the method for separating isoprene by front-end hydrogenation one-stage extraction as claimed in claim 1 or 2 is characterized in that, pre-weight-removing column has 70～130 number of theoretical plates, and reflux ratio is 5～20, and tower top temperature is 40～60 ℃, from the middle part charging.
6. the method for separating isoprene by front-end hydrogenation one-stage extraction as claimed in claim 1 or 2 is characterized in that, weight-removing column has 70～150 number of theoretical plates, and reflux ratio is 7～20, and tower top temperature is 40～60 ℃, from underfeed.
7. the method for separating isoprene by front-end hydrogenation one-stage extraction as claimed in claim 1 or 2, it is characterized in that described azeotropy rectification column has 70～200 theoretical stages, from tower middle part charging, based on the material of isoprene and the weight ratio of iso-pentane is 20: 0.5～5, and reflux ratio is 50～120.
8. the method for separating isoprene by front-end hydrogenation one-stage extraction as claimed in claim 1 or 2, it is characterized in that palladium-based catalyst or nickel-base catalyst are housed, and reaction conditions is: reaction pressure 1.0～5.0MPa in hydrogenator, 20～150 ℃ of temperature of reaction, liquid hourly space velocity 0.1～10h
-1
9. the method for separating isoprene by front-end hydrogenation one-stage extraction as claimed in claim 1 or 2 is characterized in that, extractive distillation column uses acetonitrile, dimethyl formamide or N-Methyl pyrrolidone as solvent.
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| CN102021015B (en) * | 2009-09-10 | 2013-05-01 | 中国石油化工集团公司 | Tar dissolving method for extracting C4 hydrocarbon and C5 hydrocarbon by using dimethylformamide as solvent |
| CN103086822B (en) * | 2011-11-02 | 2016-03-30 | 中国石油化工股份有限公司 | A kind of separation method of m-pentadiene |
| CN104058915B (en) * | 2013-03-20 | 2016-09-21 | 中国石油化工股份有限公司 | The method of hydrogenation distillation separation cracking C 5 fraction |
| CN112457152B (en) * | 2019-09-09 | 2022-07-05 | 中国石油集团工程股份有限公司 | Method and device for purifying dicyclopentadiene |
| CN114516777A (en) * | 2022-03-02 | 2022-05-20 | 青岛伊科思技术工程有限公司 | Energy-saving method of isoprene refining system |
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| US4647344A (en) * | 1983-10-21 | 1987-03-03 | Basf Aktiengesellschaft | Recovery of isoprene from a C5 -hydrocarbon mixture |
| CN1194945C (en) * | 2002-10-16 | 2005-03-30 | 中国石油化工股份有限公司 | Separating method for cracking C5-fraction |
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| US4647344A (en) * | 1983-10-21 | 1987-03-03 | Basf Aktiengesellschaft | Recovery of isoprene from a C5 -hydrocarbon mixture |
| CN1194945C (en) * | 2002-10-16 | 2005-03-30 | 中国石油化工股份有限公司 | Separating method for cracking C5-fraction |
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