CN1246271C - Olefine separation method - Google Patents
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- CN1246271C CN1246271C CN 00133129 CN00133129A CN1246271C CN 1246271 C CN1246271 C CN 1246271C CN 00133129 CN00133129 CN 00133129 CN 00133129 A CN00133129 A CN 00133129A CN 1246271 C CN1246271 C CN 1246271C
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Abstract
A protection bed with a molecular sieve is regenerated in an adsorption method for separating alkene from paraffin hydrocarbon in a method for recovering worthy hydrocarbon from the void volume of a protection bed. The method comprises the steps that the molecular sieve firstly contacts material flows to be cleaned; meanwhile, initial effluent is led into a residual liquid tower to revover alkene from the void volume of the protection bed. Then, the effluent of the protection bed turns to different fractionating towers.
Description
Technical field
The present invention relates to a kind of from raw mix the method for fractionation by adsorption hydrocarbon, this raw mix contains hydrocarbon and the dissimilar hydrocarbon that for example obtains from the alkene of paraffinic hydrocarbons separates.More specifically take off, the present invention relates to a kind of renovation process that in this chemical separation method, is used as guard bed molecular sieve.
Background technology
Molecular sieve is widely used in separate hydrocarbons.For example, the adsorption separating method of known in the prior art use adsorbent of molecular sieve is a kind of effective means for separate linear alpha-olefin from raw mix, contain linear alpha-olefin and hydrocarbon in this raw mix, such as paraffinic hydrocarbons with identical molecular-weight average or non-linear alkene with similar volatile other kind.In whole nation meeting in August, 1987 in summer of the american chemical engineering research institute (Amercian Institute of Chemical Engineers) that Minnesota State Minneapolis holds, the Olex by name that delivers by J.A.Johnson, S.Raghuram and P.R.Pujado: prepare in the article of method (Olex:A Process for Producing High PurityOlefins) of high purity olefin and set forth such method.The document has been described the method for simulation moving-bed (SMB) adverse current fractionation by adsorption of separation of lighter normal olefine from similar paraffinic hydrocarbons.In U.S3510423, carried out similar but more detailed description for the simulation moving method that separates linear alpha-olefin by people such as R.W.Neuzil application.
Among the US-A-5276246 that asks in people such as B.McCulloch, disclose and adopted low acidity SiO 2 molecular sieve, for example silicite or ZSM molecular sieve separate the adsorption separating method of positive alkene from the mixture of positive alkene and branched-chain alkene.
Disclosing paraffin conversion in the US5300715 of B.V.Vora application is the integrated approach of alkene.This method comprises paraffin dehydrogenation, and the alkene in the paraffin/olefin mixture that reclaims from the effluent of dehydrogenation section is carried out fractionation by adsorption.This patent has been described one and has been used for optionally removing aromatic hydrocarbons from paraffin/olefin mixture, makes the conversion zone of molecular sieve (being used for the fractionation by adsorption paraffin/olefin mixture) inactivation to prevent aromatic hydrocarbons.Remove aromatic substance and also helped the carrying out of dehydrogenation section in present method.This patent has instructed the aromatic substance section of removing may contain molecular sieve, and it can be regenerated as required.
Summary of the invention
In particular form, the present invention is the method for separating alkene by fractionation by adsorption from paraffinic hydrocarbons, it is characterized in that using this method with the guard bed regeneration of molecular sieve, and this molecular sieve guard bed being used for removed aromatic hydrocarbon impurities from the feed stream of present method.Effusive internal flows is used as flushing and regenerative raw materials, make regeneration incorporate in the preferred separation method, eliminated outside fluidic needs, the while also makes the change of the recovery of regrowth and material component easier.General embodiment of the present invention is characterised in that the method for separating first hydrocarbon from the feed stream that contains first hydrocarbon (first hydrocarbon) and at least a other hydrocarbon, this method has been used segregation section, feed stream is contacted with molecular sieve material, and molecular sieve is contacted with strippant.Use is in the used strippant logistics of segregation section, raw material is at first cleaned from guard bed, and guard bed effluent fed in the separation column that this method uses to separate strippant and raffinate compound, and subsequently the strippant logistics is continued by guard bed, but the strippant that guard bed effluent is fed this method use reclaims in the separation column to reclaim strippant, with the guard bed regular regeneration of molecular sieve used in present method.
Particularly, the present invention relates to by in segregation section, feedstream being contacted with molecular screen material and molecular screen material being contacted with strippant, the method of from the feedstream that comprises described first hydrocarbon and at least a other hydrocarbon, separating first hydrocarbon, this method comprises at least a portion feedstream guard bed and by the following method regularly with the guard bed regeneration of the molecular sieve that uses in this method by molecular sieve, promptly at first use in the used strippant logistics of segregation section and clean from the feedstream in guard bed, and the effluent in guard bed is circulated in first separation column that this method uses to separate strippant and raffinate compound, subsequently continuously with the strippant logistics by in the after-fractionating tower guard bed but that use in this method that directly guard bed effluent circulated to reclaim strippant.
Description of drawings
Accompanying drawing is the technology flow schematic diagram of simplifying, and shown to be positioned at parallel guard bed 4 and 21 of adsorption chamber 7 upstreams, and shown separation column 12,26 and 29 used in present method.
Embodiment
Alkene is a kind of very useful compound.They can generate polymkeric substance with id reaction, or carry out alkylated reaction with other molecule in petrochemical industry and petroleum refining industry, to prepare various chemical productss.For alkene is used most effectively, or make the formation of by product minimum, need alkene to have quite high purity usually.In some other occasions, do not wish that non-alkenes appears in the logistics that contains alkene, because they can form undesirable by product.In above-mentioned two kinds of occasions, need or wish at least for example to separate in the paraffinic hydrocarbons from non-alkenes with alkene.On the other hand, required alkene only is a kind of alkene of particular type, for example positive alkene or alpha-olefin, and it appears at the alkene that contains other type, for example in the mixture of branched-chain alkene.
When the alkene of special needs mixes with the chemical substance with different relative volatilities, adopt simple fractionating method usually, from mixture, reclaim alkene.But, under many circumstances, existing in the mixture of alkene and contain one or more different hydrocarbon, its volatility is quite similar, and this makes by the fractionation separates difficulty or impossible that becomes.By adopting paraffinic hydrocarbons or alkane mixture dehydrogenation to prepare the alkene common example that comes to this.Dehydrogenation reaction can not be carried out fully because of the constraint of molecular balance, and the product logistics of dehydrogenation section is to have the paraffinic hydrocarbons of identical chemical general formula and the uniform mixture of alkene.These compounds have very close fusing point, and by fractionation their separate are unusual difficulty.At this moment, fractionation by adsorption is common the most economic separation method, uses a kind ofly to a kind of material during separation, and for example alkene is compared other material sorbent material selectively.
According to using of present method, the alkene that reclaims at the main alkene segregation section of present method both can be normal olefine, can be branched-chain alkene also, and perhaps the two all is.The hydrocarbon that does not reclaim in the feed stream can be dissimilar alkene or paraffinic hydrocarbons, or the mixture of the two.Therefore, present method can be exclusively used in and reclaim positive alkene from the mixture that contains isoolefine and/or paraffinic hydrocarbons.Olefin product can contain for example individual molecule of isopentene, or the mixture of n-hexylene and nhepene for example.Olefin product also can contain the homologue in several carbon atom number ranges, for example C
10-C
14Normal olefine can be used for preparing the linear alkylbenzene as detergent precursors.
Fractionation by adsorption can use multiple different technology to carry out, and for example two or more fixed beds are operated-used to oscillating bed, and circulation is adsorbed and regeneration step betwixt; The sorbent material of moving-bed operation-wherein is in adsorption stage and stripping stage transmission; And simulation moving-bed (SMB) operation, for example referring to US-A-3510423,3720604,3723302 and 3755153 described.Here, can to incorporate written or printed documents into bright for the background technology of description that relates to simulated Moving Bed Adsorption Separation Technology, nomenclature in these patents and wherein can be used for the sorbent material of fractionation by adsorption.Although simulation moving-bed separation (described in for example above citing document) be preferred, this mode that sorbent material contacts with feed stream is not a restrictive factor of the present invention.For the different adsorption technology of any of these, and any method that has adopted suitable guard bed, strippant and separation column, the adsorbent reactivation technology of Ti Chuing all is suitable for here.
In one embodiment, segregation section is continuous adsorption segregation section, contains in the raw material the deleterious material of the molecular sieve of continuous adsorption segregation section, and feedstream has adsorbed poisonous substance with guard bed contacting.
Adsorption separating method contains the adsorption step (wherein sorbent material being contacted with the raw material that contains alkene) and the desorption procedure (wherein, the alkene that is adsorbed by selectivity is removed) of carrying out basically under adsorption conditions from sorbent material under desorption condition.Preferably with adsorption step under the quite similarly condition that adopts, contact with the desorb compound by sorbent material and to promote desorption procedure.But, can pass through to change temperature or pressure, or, the alkene that is adsorbed be removed from sorbent material the two mode that all changes.Promptly if desired, can use heat swing fractionation by adsorption operation or the operation of pressure oscillating fractionation by adsorption.The pressure oscillating system is operated in vapor phase, and olefin separation steps of the present invention can adopt vapor phase absorption and desorption condition.These selectable desorption methods do not use strippant usually, use strippant can limit the application of present method.
Desorption procedure produces the operation logistics, and this operation logistics contains by the mixture of the strippant that uses in the alkene of desorb and this method.This operation logistics is counted as the extract flow of preferred feeding strippant separation and recovery zone (strippant is circulated) in technology.This section contains the separation column of mentioning in the prior art usually, as the extraction tower that reclaims strippant.Not adsorbent component in the feed stream is removed with the operation logistics that is called raffinate stream herein.If suitable, also this logistics can be fed separation column-it is referred to as raffinate tower here.
The aromatic hydrocarbons that occurs in the feed stream of present method will be collected in the preferred adsorbent that is used for from the positive alkene of feedstream separation.This can produce several disadvantageous effects to the performance of present method.At first, aromatic hydrocarbons will occupy the reactive site on the sorbent material, stop these positions to be used in separation.The capacity and the technological ability of molecular sieve reduce thereupon.If aromatic compound is accumulated continuously, will reach equilibrium concentration.When reaching balance, can not obtain aromatic compound in sorbent material online, they will be by adsorption stage so, and appears in extract and the raffinate stream.In the positive alkene that reclaims from extract flow, aromatic hydrocarbons is considered impurity usually.The aromatic hydrocarbons that occurs in raffinate stream will be concentrated in the paraffinic hydrocarbons.These materials generally are circulated to alkene and generate section, for example in the dehydrogenation section.Do not wish that generally aromatic hydrocarbons enters in the catalytic dehydrogenation section because aromatic hydrocarbons can with olefin alkylation, and produce by product.As described in the US-A-5300715 that quotes previously, occur aromatic hydrocarbons in the raw material of dehydrogenation section or the product and also have other undesirable influence.So, do not wish to make aromatic hydrocarbons, comprise that benzene enters main adsorption stage.
The sorbent material that the present invention adopts is preferably by inorganic oxide, for example the molecular sieve of silicon-dioxide and aluminum oxide formation; It is silico-aluminate.Such material comprises the known zeolite that can buy, for example zeolite Y and X zeolite.The crystallite sieve texture that many zeolites have is very important for sorbent material to the selectivity of alkene.But it is believed that the present invention can regenerate inorganic oxide material, this material is not a zeolite, but at the guard bed sorbent material that is used as that is arranged in alkene master segregation section upstream.Term " molecular sieve " comprises a variety of inorganic oxides that are suitable as guard bed sorbent material and/or are used as the sorbent material that separates alkene, and it comprises the silicite material of mentioning in the above-mentioned reference.Silicite are molecular sieves of a kind of high silica alumina ratio, because of it does not have ion-exchange capacity, so be not zeolite.In US-A-4061724,4073865 and 4104294, silicite there is more detailed description.Another type that can be used as the inorganic oxide molecular sieve of sorbent material is a ZSM type zeolite, and is for example disclosed among US-A-3702886 (ZSM-5), 38324489 (ZSM-12), 4016245 (ZSM-35) and 4046859 (ZSM-38).
The sorbent material that is preferred for segregation section is attrition resistant, and diameter is about the particulate of 20-40 order (US), the tackiness agent by for example clay or aluminum oxide and the mixture of X type or y-type zeolite is extruded or spraying drying forms.Described in the visible US-A-2822244 of X type zeolite, and described in the visible US-A-3130007 of y-type zeolite.Available one or more are selected from that original sodium ion carries out ion-exchange in other positively charged ion of basic metal, alkaline-earth metal and coinage metals and the zeolite.Preferred metals is drawn together lithium, potassium, calcium, strontium and barium.Also these two or more melts combine can be used.The preferred ion exchange of these materials is on close level low.The 13X zeolite that highly preferred sorbent material is the sodium type.Identical or different molecular sieve can be used for adsorbing the sieve poisonous substance in guard bed.The molecular sieve that uses in guard bed preferably carries out height with the positively charged ion of hope and exchanges.Be used for the X zeolite that guard bed molecular sieve is preferably the lithium exchange.
The operational issue that relates to the fractionation by adsorption of alkene is that some compound that occurs in the feed stream accumulates on the reactive site of sorbent material.These compounds are so tight with combining of reactive site, so that the desorption procedure of olefin recovery can not be removed.Therefore they make these positions ineffective for the absorption of alkene.These compounds are commonly called the sorbent material poisonous substance.Because more poisonous substances are accumulated from feedstream, adverse influence is increased, the capacity of sorbent material and the effect of entire method reduce.The component of such poisonous substance can change, and the prevailing composition that is run in present method is diolefine and aromatic hydrocarbons.It comprises and contains for example aromatic hydrocarbons of sulphur or oxygen of heteroatoms that heteroatoms both can also can be positioned on its alkyl group side chain on ring structure.The aromatic substance that molecular weight is bigger is comparatively main poisonous substance.The object lesson that can be considered the compound of poisonous substance in a preferred embodiment of the invention comprises benzene, toluene, other alkylating benzene, divinyl, dimethylbenzene, ethylbenzene, 1,2,3,4-tetralin, 1,2 indane, alkylation-dinaphthalene and biphenyl.Other poisonous substance comprises aniline, cresols, pyridine, naphthalane and 1,2 tetraline; Oxide compound, for example phenol, cycloalkanes phenol, naphthols, cumarone and dibenzofuran; Nitrogenous compound, for example pyrroles, pyridine, indoles, cycloalkanes-pyridine and carbazole; And the compound of sulfur-bearing, for example thionaphthene, tetramethylene sulfone, dimethyldibenzothiophene, thiophene and benzenethiol (benzenthiol).
The purpose of this invention is to provide the method for removing aromatic hydrocarbons in a kind of adsorbent of molecular sieve that from the protection bed of adsorption separating method, uses.Another purpose provides a kind of like this method, adapts to very much with strippant that is used for the isolating simulated moving bed process of alkene and device.
Prior art is pointed out, can prevent that poisonous substance is used in the molecular sieve inactivation that separates alkene by in the method described in the US-A-5300715 that preceding quotes.In the method, adopt the selectivity aromatic substances to remove section and prevent that aromatic substances from entering the fractionation by adsorption section.Emphasize that in this patent aromatic substances is removed section can adopt reproducible sorbent material, for example molecular sieve.The document is general description also, can be by using the adsorbent reactivation that liquid benzene will this section.And in the method for the invention, then do not wish to use benzene as regenerator because a spot of benzene will remain in inevitably guard bed in, and be moved downward to main fractionation by adsorption section, cause the molecular sieve inactivation of this section.
This regeneration step comprises that the internal space and the adjoining in the part of container of void volume, the line of pipes of feed stream molecular sieve from guard bed that at first will contain alkene remove.At this moment, feed stream will flow in the molecular sieve in another container and maybe may stop to flow (if present method only adopted one guard bed).Feed stream flows into storage vault rather than directly flows to segregation section is comparatively suitable.By with the strippant logistics by the desorb bed, feed stream is developed from molecular sieve.This logistics does not have aromatic substances basically and obtains in technology.This step is preferably carried out under the condition similar to handling guard bed normal operating condition.The time that this rinse step carries out is only for to remove the needed time substantially with the feed stream of remnants from guard bed.The guard bed effluent that forms in this step is circulated in SMB type adsorption separation unit in the used raffinate tower.This tower is used for present method, raffinate (not adsorbing) and the strippant compound that is present in the raffinate stream are separated from adsorption stage.Can subsequently the strippant that reclaims be circulated and the raffinate compound be discharged from segregation section, and need not extra equipment.Because all compounds in the guard bed void volume usually with the raffinate compound in identical boiling spread, so the interior all substances of void volume will be concentrated in the raffinate stream.Alkene in the void volume in the material will can not stayed in the absorbing process, but can not abandon from whole technology.The raffinate that reclaims is circulated to operating unit usually, dehydrogenation unit for example, and this unit produces the feedstream in adsorption separation unit.Any compound in guard bed void volume can not abandoned into peripheral equipment and lose.The liquid that cleaning preferably includes the 1-3 bed volume passes through guard bed.
In the next procedure of present method, the sorbent material in guard bed is actually by aromatic hydrocarbons is removed and regenerated from sorbent material, and aromatic hydrocarbons is enriched in the separating unit from raw material.This operation is by crossing guard bed carrying out with desorb logistics Continuous Flow.But guard bed effluent is transferred, and is not to flow to the raffinate tower.Effluent can be admitted to external discrete and recovery zone, but preferably sends into separation column, and this separation column is in order from the aromatic substances of removing the strippant compound separation to be come out and to add in the technology.This regeneration step can be carried out under the guard bed normal sorption condition that adopts, and preferred temperature is about 30-170 ℃.Regeneration step is the time of enough length, so that at least 2, the strippant liquid of preferred 5-12 volume is by guard bed.Feed stream this location restore flow to guard bed in.This has illustrated another advantage of the present invention, promptly need not after regeneration step regenerator to be removed from guard bed.On the contrary, we do not wish to reuse to be full of the guard bed of benzene very much, and benzene is to recommend as the regenerating medium that is fit in the citing document.Benzene is a kind of demulcent sorbent material poisonous substance, because its can be in the adsorbent surface enrichment, and will having a negative impact to lock out operation.In the method, need not regenerator is developed from guard bed.But,, will contain the strippant of high density from guard bed (when placing logistics) effusive initial fluid because be full of strippant in the guard bed void volume.The liquid of initial several bed volumes of removing from regenerated is guard bed will be passed in the raffinate tower, to reclaim strippant.To cause a large amount of strippants to enter in the main chamber and perturbation operation like this.The new guard bed initial effluent of regenerated can be passed in any separation column of the recovery strippant in the technology.
In one embodiment, after the guard bed regeneration fully, feedstream restarts to flow to that just regenerated is guard bed, and the guard bed initial effluent of regenerated is passed into first separation column.
By using the guard bed sorbent material of suitable intensity, make that use becomes possibility as regenerating medium with the strippant logistics.The high strength sorbent material requires to use high-intensity strippant, and for example benzene perhaps carries out some to operational condition and adjusts, for example higher temperature.In the present invention, preferably the active constituent of aluminosilicate molecular sieves as guard bed sorbent material used.In the main adsorption stage of lock out operation, can adopt different sorbent materials.The preferred guard bed sorbent material that contains X zeolite that uses, the X zeolite of lithium exchange highly preferably uses because of its stability to the inventive method.Contain the 0.5-3.0wt% lithium of having an appointment in such zeolite.
Can understand the operation of the inventive method with reference to accompanying drawing, accompanying drawing of the present invention will lead to the simplification process flow sheet of simulation moving-bed feed stream purifying for using two oscillating beds.Feedstream that produce in dehydrogenated operation as shown in drawings, and that contain the mixture of normal paraffin and positive alkene (identical with the molecular weight of normal paraffin) enters in the technology by pipeline 1.During raw material feeds two guard bed 4 and 21 by the manifold system one.At this moment, as shown in drawings, the feedstream of pipeline 1 flows into guard bed 4 upper end by pipeline 3 and subsequently by being retained in the molecular sieve adsorbent bed in guard bed.The guard bed aromatic hydrocarbons that has one or two ring that optionally absorbs.These aromatic hydrocarbons are present in the feedstream with lower concentration usually, and its concentration is lower than about 4000-6000ppm, and may be lower than 100ppm.Therefore all feedstreams that enter have all passed through guard bed and have discharged through pipeline 5 basically.Subsequently feedstream is transferred to pipeline 6, made it enter bigger main fractionation by adsorption chamber 7.
Many beds system that 7 expressions of fractionation by adsorption chamber are adopted in simulation moving-bed operation usually.These systems contain about 30 the inferior beds of the 10-that has an appointment (subbeds), and inferior bed is by fluid collection and distribute grizzly bar to separate, and these grizzly bars also are the points that the operation logistics enters adsorption stage and removes from adsorption stage.Therefore, in a plurality of inferior bed of this system each, all have at least one to add and remove the fluidic separation point.According to the method for describing in detail in the document of quoting, feedstream feeds position that adsorption chamber 7 and multiple other logistics entered or left adsorption chamber and increases progressively along the length direction of adsorption chamber.This continuous countercurrent that brings cumulative trend reinforced and that remove material to cause the feedstream by adsorption bed along with using the pump circulation logistics of being carried by pipeline 11 flows and the efficient simulation of removing continuously of raffinate and extract flow.Raffinate stream contains the strippant (being collected in the void volume of this strippant because of the adsorption bed of its section of being present in 7) that the component that does not adsorb in the feedstream adds the variable of collection.By pipeline 10 raffinate stream is removed from adsorption stage 7, and feed in the raffinate tower 26, to separate raffinate component and strippant component through pipeline 25.By pipeline 27 strippant is reclaimed as overhead stream, the raffinate component is reclaimed as tower base stream through pipeline 28.The raffinate stream of pipeline 28 is circulated in the dehydrogenation section of the feed stream that produces pipeline 1.
In adsorption separating method, no matter be that raffinate stream or extract flow all can contain the compound of regarding present method important products as.In the method, alkene is in the product of expecting in the raw material, and it is retained on the sorbent material in the adsorption chamber 7.By the strippant logistics is entered the difference of absorber portion 7 by pipeline 8, these absorbed alkene are removed from sorbent material.The desorb logistics is by the mobile formation (it is carried by pipeline 9) that causes extract flow of load molecular sieve or other sorbent material of adsorption stage 7.This logistics is removed on the another one point of adsorption chamber 7.Extract flow contains the mixture that the alkene of removing adds the strippant compound of variable from raw material.This mixture is fed extraction column 12 by pipeline 9.In extraction column, be the tower base stream that contains olefin product-remove-and the overhead stream that contains the strippant compound with the mixture separation of the strippant that enters and alkene by pipeline 13 by fractionation.Strippant can comprise the component of a kind of alkene as it.Preferred strippant compound is low-molecular-weight alkene.Further preferably, the molecular weight of alkene is lower than remaining alkene.The strippant of Hui Shouing is removed by pipeline 14 and is divided into two portions like this, and wherein to enter pipeline 16 guard bed to regenerate for a part, and a more part is extracted out by pipeline 15.Usually the material of material in pipeline 27 in the pipeline 15 feeds pipeline 8 as the strippant of present method, but it directly flows to external source (external source) as shown in the figure, as the cat head material, be used for required storage and the distribution system of present method operation.
When the sorbent material in guard bed 4 was used to handle feedstream, the sorbent material in guard bed 21 was reproduced.Can expect that the required time of regenerating is handled the time much shorter of raw material than adsorbent bed.Adsorbent bed in one of guard bed 4 and 21 useful cycling time all can by adjust guard bed in the amount of molecular sieve adjust.So, can adjust the flow velocity of guard bed size and regeneration, make regenerative operation the most economical.In regenerative process, the strippant logistics enters the manifold system that shifts raw material by pipeline 16.The strippant logistics of the pipeline 16 manifold pipeline 20 of will flowing through enters guard bed 21.Strippant is by the liquid in all the other void volumes that at first will clean the void volume of molecular sieve bed and container that is associated and pipeline that flow of molecular sieve.This flushing logistics that will form through pipeline 22 bands enters pipeline 23.At first, the mixture that contains of the guard bed outflow logistics of regenerated adds the material that remains in the guard bed void volume for the strippant as regenerator.Because the resistates in guard bed is a feedstream, owing to the alkene that contains our needs has tangible value.It also contains the paraffinic hydrocarbons to dehydrogenation section capable of circulation.So, do not wish to discard this material, it is fed pipeline 24, the pipeline 25 of flowing through enters raffinate tower 26.Therefore, all in guard bed basically are reproduced raw material and all are collected.Because compound not of the same race or boiling point adopt the fractionation by adsorption of carrying out in present method usually near adopting fractionation not conform to actual time.In example of the present invention, paraffinic hydrocarbons in the raw material and alkene have close boiling point, and enter together in the raffinate stream of pipeline 28.
The above-mentioned rinse step that carries out the material component recovery only carries out the short period.The strippant Continuous Flow is guard bed excessively, begin to remove the aromatic hydroxy compound that is enriched in the remnants on the adsorption bed.Do not wish these materials are fed the raffinate tower.So the guard bed middle logistics that flows out that is reproduced flow to pipeline 30 from pipeline 24.Guard bed effluent in the regeneration is therefore by pipeline 30, enter additional separation column 29, its design and operational condition make the hydrocarbon that enters be separated into strippant-remove from pipeline 31 as overhead stream, and the clean tower base stream that contains aromatic hydrocarbon impurities, through pipeline 32 outflows.Guard bed reach enough regeneration level after, by the analysis of flowing out logistics is determined, or, make by guard bed sorbent material to stop to flow by to the simple time control of sorbent material flow with measure.Therefore, it is quite few to wish to enter the amount of substance of separation column 29.Because the substance transfer in the void volume, the component that enters the material of tower 29 and tower 12 and 26 will change in time.Therefore adopt collection and mixing drum to make the material component that flows to tower stable usually.These optional projects are not shown in the diagram to be gone out.
Illustrated method can be carried out many variations.For example, adsorption stage or chamber 7 can comprise that two or more are used for the chamber of the many beds that separate of simulation moving-bed operation.In addition, adsorption chamber 7 also can contain the adsorbent bed of operating in the oscillating bed mode in a large number.In addition, need not in the method to use two guard bed.Present method can adopt single guard bed or three or more guard bed.Adsorption chamber 7 also can comprise different sorbent materials-raw material way of contact, for example true moving-bed system or even fluidized-bed fractionation by adsorption system.
Aforesaid method is used for the fractionation by adsorption of alkene and paraffinic hydrocarbons.The isolation technique of alkene and paraffinic hydrocarbons can not be subjected to the constraint of present method specification sheets, because it relates to the guard bed renovation process of the feedstream that is used to prepare separating step basically.So segregation section or adsorption chamber 7 can be replaced by the segregation section of other form, for example crystallized region or liquid-liquid separation section.
Therefore the preferred embodiment of the invention is characterised in that the simulated moving bed process that separates linear alpha-olefin from the raw material of the hydrocarbon that contains linear alpha-olefin and other type, this method comprises feed stream is contacted with molecular sieve bed (its contact conditions is that alkene is kept by selectivity on molecular sieve, and the last raffinate stream of delivering to the raffinate tower that forms), by molecular sieve is contacted with strippant, from molecular sieve, reclaim remaining alkene, it is characterized in that being used for removing the guard bed of aromatic hydrocarbons by regular regeneration from raw material, reclaiming process comprises and at first purifies guard bed-regeneration by will containing strippant by guard bed, simultaneously guard bed effluent is circulated into the raffinate tower to reclaim the feedstream component, and subsequently continuously with regeneration by guard bed, and guard bed effluent circulated into the strippant recovery tower.Specifically, this method is separated linear alpha-olefin from the feedstream of the hydrocarbon that contains linear alpha-olefin and other type, feedstream contacts in segregation section with molecular sieve bed, contact conditions for being retained on the molecular sieve and the final raffinate stream that forms with making olefine selective, raffinate stream feeds in first separation column of operating as the raffinate tower, by molecular sieve being contacted with strippant reclaiming alkene remaining in the molecular sieve, guard bedly be used to remove aromatic hydrocarbons.Sometimes, after guard bed regeneration is finished, the guard bed feed stream that is used to handle additional quantity once more.Feed stream begins to flow once more, and newly the guard bed liquid stream of regenerated is passed into the raffinate tower and goes to subsequently in the main bed of molecular sieve.
Claims (8)
1. by in segregation section, feedstream being contacted with molecular screen material and molecular screen material being contacted with strippant, the method of from the feedstream that comprises described first hydrocarbon and at least a other hydrocarbon, separating first hydrocarbon, this method comprises at least a portion feedstream guard bed and by the following method regularly with the guard bed regeneration of the molecular sieve that uses in this method by molecular sieve, promptly at first use in the used strippant logistics of segregation section and clean from the feedstream in guard bed, and the effluent in guard bed is circulated in first separation column that this method uses to separate strippant and raffinate compound, subsequently continuously with the strippant logistics by in the after-fractionating tower guard bed but that use in this method that directly guard bed effluent circulated to reclaim strippant.
2. the process of claim 1 wherein guard bed in used molecular sieve be silico-aluminate, its component is with to separate used molecular sieve different.
3. the process of claim 1 wherein that a kind of component of strippant is an alkene.
4. the process of claim 1 wherein that segregation section is continuous adsorption segregation section, contain in the raw material that feedstream has adsorbed poisonous substance with guard bed contacting to the deleterious material of the molecular sieve of continuous adsorption segregation section.
5. the method for claim 1, wherein this method is separated linear alpha-olefin from the feedstream of the hydrocarbon that contains linear alpha-olefin and other type, feedstream contacts in segregation section with molecular sieve bed, contact conditions for being retained on the molecular sieve and the final raffinate stream that forms with making olefine selective, raffinate stream feeds in first separation column of operating as the raffinate tower, by molecular sieve being contacted with strippant reclaiming alkene remaining in the molecular sieve, guard bedly be used to remove aromatic hydrocarbons.
6. each method of claim 1-5, wherein guard bed in used molecular sieve be the X type zeolite of lithium exchange.
7. the method for claim 5, after the wherein guard bed regeneration fully, feedstream restarts to flow to that just regenerated is guard bed, and the guard bed initial effluent of regenerated is passed into first separation column.
8. the method for claim 5, wherein a kind of component of strippant is an alkene, its molecular weight is lower than remaining alkene.
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| CN 00133129 CN1246271C (en) | 2000-08-18 | 2000-08-18 | Olefine separation method |
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| CN 00133129 CN1246271C (en) | 2000-08-18 | 2000-08-18 | Olefine separation method |
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| CN1339425A CN1339425A (en) | 2002-03-13 |
| CN1246271C true CN1246271C (en) | 2006-03-22 |
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| CN 00133129 Expired - Fee Related CN1246271C (en) | 2000-08-18 | 2000-08-18 | Olefine separation method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020177235A1 (en) * | 2019-03-04 | 2020-09-10 | 内蒙古伊泰煤基新材料研究院有限公司 | METHOD OF SEPARATING α-OLEFIN BY SIMULATED MOVING BED PROCESS |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101462919B (en) * | 2007-12-17 | 2014-05-28 | 环球油品公司 | Alkene separation method |
| CN110938465B (en) * | 2019-11-19 | 2021-12-10 | 中海油天津化工研究设计院有限公司 | Method for multi-component adsorption separation of gasoline |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020177235A1 (en) * | 2019-03-04 | 2020-09-10 | 内蒙古伊泰煤基新材料研究院有限公司 | METHOD OF SEPARATING α-OLEFIN BY SIMULATED MOVING BED PROCESS |
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| Publication number | Publication date |
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| CN1339425A (en) | 2002-03-13 |
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