CN1267388C - Method for separating n-alkane from C5 to C6 alkane isomerized products - Google Patents
Method for separating n-alkane from C5 to C6 alkane isomerized products Download PDFInfo
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- CN1267388C CN1267388C CN 200310122456 CN200310122456A CN1267388C CN 1267388 C CN1267388 C CN 1267388C CN 200310122456 CN200310122456 CN 200310122456 CN 200310122456 A CN200310122456 A CN 200310122456A CN 1267388 C CN1267388 C CN 1267388C
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- fractionation
- adsorption
- desorbing agent
- normal paraffin
- pentane
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- 238000000034 method Methods 0.000 title claims abstract description 39
- 150000001335 aliphatic alkanes Chemical class 0.000 title claims abstract description 27
- QWTDNUCVQCZILF-UHFFFAOYSA-N isopentane Chemical compound CCC(C)C QWTDNUCVQCZILF-UHFFFAOYSA-N 0.000 claims abstract description 62
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 57
- 238000003795 desorption Methods 0.000 claims abstract description 53
- AFABGHUZZDYHJO-UHFFFAOYSA-N dimethyl butane Natural products CCCC(C)C AFABGHUZZDYHJO-UHFFFAOYSA-N 0.000 claims abstract description 34
- 239000002994 raw material Substances 0.000 claims abstract description 28
- 238000011010 flushing procedure Methods 0.000 claims abstract description 12
- 239000007791 liquid phase Substances 0.000 claims abstract description 8
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 5
- 238000001179 sorption measurement Methods 0.000 claims description 92
- 239000012188 paraffin wax Substances 0.000 claims description 51
- 238000006317 isomerization reaction Methods 0.000 claims description 42
- 239000007788 liquid Substances 0.000 claims description 39
- 238000005194 fractionation Methods 0.000 claims description 38
- 239000002594 sorbent Substances 0.000 claims description 24
- 238000010521 absorption reaction Methods 0.000 claims description 16
- 230000002262 irrigation Effects 0.000 claims description 15
- 238000003973 irrigation Methods 0.000 claims description 15
- 239000002808 molecular sieve Substances 0.000 claims description 10
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims description 10
- 241000282326 Felis catus Species 0.000 claims description 7
- 238000005406 washing Methods 0.000 claims description 7
- 239000012530 fluid Substances 0.000 claims description 6
- 238000009835 boiling Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 4
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical group CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 2
- 238000004821 distillation Methods 0.000 claims description 2
- ZJKABZNFELLAQQ-UHFFFAOYSA-N octane Chemical compound CCCCCCCC.CCCCCCCC ZJKABZNFELLAQQ-UHFFFAOYSA-N 0.000 claims description 2
- 238000000926 separation method Methods 0.000 abstract description 29
- 229930195733 hydrocarbon Natural products 0.000 abstract description 3
- 150000002430 hydrocarbons Chemical class 0.000 abstract description 3
- 230000000274 adsorptive effect Effects 0.000 abstract 4
- 239000004215 Carbon black (E152) Substances 0.000 abstract 1
- 239000000047 product Substances 0.000 description 29
- 239000000203 mixture Substances 0.000 description 17
- TVMXDCGIABBOFY-UHFFFAOYSA-N octane Chemical compound CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 15
- 239000003502 gasoline Substances 0.000 description 12
- IJDNQMDRQITEOD-UHFFFAOYSA-N sec-butylidene Natural products CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 5
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 5
- ZFFMLCVRJBZUDZ-UHFFFAOYSA-N 2,3-dimethylbutane Chemical compound CC(C)C(C)C ZFFMLCVRJBZUDZ-UHFFFAOYSA-N 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 150000003384 small molecules Chemical class 0.000 description 3
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical group CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- GDOPTJXRTPNYNR-UHFFFAOYSA-N methylcyclopentane Chemical compound CC1CCCC1 GDOPTJXRTPNYNR-UHFFFAOYSA-N 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 238000010926 purge Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 101000643895 Homo sapiens Ubiquitin carboxyl-terminal hydrolase 6 Proteins 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- 102100021015 Ubiquitin carboxyl-terminal hydrolase 6 Human genes 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000004996 alkyl benzenes Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000001833 catalytic reforming Methods 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 150000002431 hydrogen Chemical group 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000010297 mechanical methods and process Methods 0.000 description 1
- 230000005226 mechanical processes and functions Effects 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000004230 steam cracking Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The present invention relates to a method for separating normal alkane from C5 to C6 alkane isomerized products. Isopentane in raw materials is firstly removed, the raw materials are secondly led in an adsorptive separation post, and normal alkane in the raw materials is absorbed at 2.0 to 4.0MPa, 100 to 150 DEG C in a liquid phase. After the adsorptive separation post is saturated, the isopentane is used as a flushing agent to flush the adsorptive separation post, and then the adsorptive separation post is desorbed by C7 to C9 normal alkane which is used as a desorbing agent. The method can effectively separate normal alkane in light hydrocarbon isomerized products. The consumption of the desorbing agent is small, and the desorption time is short.
Description
Technical field
The present invention is a kind of method that adopts adsorption method of separation to separate positive isoparaffin from paraffins mixture, specifically, is that a kind of employing fractionation by adsorption is from C
5～C
6The method of separating normal paraffin in the alkane isomerization product.
Background technology
Along with the enhancing day by day of environmental protection consciousness, country is more and more stricter to the requirement of vehicle fuel, especially gasoline products, and the alkene in the clean gasoline, aromatic hydrocarbons and sulphur content have all been done strict restriction.Because C
5～C
6Alkane isomerization, can make the lower normal paraffin of octane value be converted into the high isoparaffin of octane value, and isomerization product is the environmental friendly product of a kind of low-sulfur, aromatic free and alkene, can be used as good gasoline blend component, improve the octane value of gasoline, make gasoline have the good capability of antidetonance.
C
5～C
6The alkane isomerization reaction is subjected to the restriction of thermodynamic(al)equilibrium, contains the normal paraffin of some amount in the product, if will further improve the octane value of product, must separate isomerization product, isolates normal paraffin wherein, makes it carry out isomerization reaction again.At present, the method for separating isomerism product mainly contains rectification method and adsorption method of separation, because C
5～C
6Aliphatic fraction is lighter, and boiling point is approaching between the isomer, and the precision of rectifying separation is restricted, and isolated normal paraffin purity is lower, and is therefore less with the amplitude of this method boosting of octane rating.Adsorption method of separation is to utilize the selection absorption property of molecular sieve pore passage to adsorbent, optionally adsorbs normal paraffin, thereby normal paraffin is separated with isoparaffin.The separation efficiency height of adsorption method of separation, energy consumption are low, the purity height of product separation, can improve C greatly
5/ C
6The octane value of isomerization product.
In early days, just, the isolation technique of isoparaffin is mainly used in the macromole normal paraffin that separates in the kerosene(oil)fraction, in order to the preparation alkyl benzene material.As USP3,309,415 to adopt the 5A molecular sieves be sorbent material, under gas phase or liquid-phase condition from C
10～C
14Or C
14 +Separate normal paraffin in the above cut, as the raw material of fine chemicals such as production washing composition, its used desorbing agent is an octane.Afterwards along with to high-octane rating, gasoline with low olefine content, and the increase of high-quality preparing ethylene by steam cracking raw materials requirement, beginning will be just, the isoparaffin adsorption separation technology is applied to light naphtha fraction, to separate normal paraffin wherein, with its further isomery to obtain more high-octane isoparaffin.
USP4,595,490 are applied to light naphtha fraction with adsorption separation technology the earliest, its used sorbent material is the 5A molecular sieve, under gas phase condition with adsorption method of separation with C
5～C
6Normal paraffin in the cut is separated, and after adsorption equilibrium, is the absorption raw material that retains in the displacer displacement sorbent material with hydrogen.This patent purges with cocurrent process earlier, and then adsorbs, and carries out countercurrent purge, adverse current desorption afterwards again.The operation that so hockets, and stream, discontinuous in the middle of when counter-current operation switches have certain time interval.
USP5,026,951 discloses under liquid-phase condition, is sorbent material with the 5A molecular sieve, and normal butane is a desorbing agent, adopts simulated moving bed technology by C
5～C
6The method of separating normal paraffin in the cut.This patent is not separated the desorbing agent in the desorption liquid, directly will contain the raw material of the desorption liquid of desorbing agent as isomerization unit, and the part desorbing agent is reclaimed by the isomerization product stabilizer tower.Though this method requires the isomerization reactor size slightly to increase, and has saved the desorbing agent separating device.
USP5,233,120 earlier with C
5～C
6Iso-pentane in the cut removes, and carries out isomerization reaction again, and then the normal paraffin in the method separating isomerism product of employing transformation absorption, and its used sorbent material is the 5A molecular sieve, and displacer is a hydrogen, and desorbing agent is an iso-pentane.
USP6, the method for 353,144 disclosed separation normal paraffins is with C
5～C
8Hydro carbons and eluant alternately feed in the adsorption stage that contains sorbent material, obtain three kinds of logistics by the adsorption stage separation, be rich in straight-chain paraffin in first logistics, be rich in the alkane of single side chain in second logistics, be rich in the alkane and the aromatic hydrocarbons of higly branched chain in the 3rd logistics, used eluant is selected from propane, butane, pentane or iso-pentane.
Above-mentioned by C
5～C
6Separate in the adsorption separating method of normal paraffin in the paraffins mixture, desorbing agent all adopts small-molecule substance, and by on the sorbent material during desorption normal paraffin, especially when liquid-phase operation, the consumption of desorbing agent will be far longer than normal paraffin adsorbed on the sorbent material, and energy consumption is huge when separating desorbing agent in the desorption liquid like this.In addition, along with the increase of raw molecule carbonatoms, its sorptive force on sorbent material strengthens, and when using small-molecule substance as desorbing agent, required time of desorption manipulation is longer, makes the efficient reduction of adsorption separation device.
Summary of the invention
The purpose of this invention is to provide a kind of employing adsorption method of separation separation of C
5～C
6The method of normal paraffin in the alkane isomerization product, this method is a desorbing agent with the macromole normal paraffin, can effectively improve desorption rate, saves the desorbing agent consumption.
The present invention is owing to use C
7～C
9Normal paraffin be that desorbing agent carries out desorption to adsorbing saturated sorbent material, than using the small molecules normal paraffin, being desorbing agent as normal butane carries out the method for desorption to sorbent material, and desorption rate improves, desorbing agent reaches balance time on sorbent material obviously reduces, thereby can shorten desorption time.In addition, macromole desorbing agent content in desorption liquid is higher, thereby can reduce the desorbing agent consumption, the energy consumption when reducing the desorbing agent lock out operation.In addition, the present invention is before fractionation by adsorption, earlier with C
5～C
6Raw material carries out rectifying separation, the isopentane separation of non-isomerization reactive behavior is wherein come out, so both alleviated the load of fractionation by adsorption operation, also alleviated the load of follow-up isomerization unit, and also can make full use of and to separate the iso-pentane that obtains irrigation as the fractionation by adsorption post.
Description of drawings
Fig. 1 is the schematic flow sheet of fractionation by adsorption operation of the present invention.
Fig. 2 is the adsorption curve that desorbing agent obtains with the octane for the present invention.
Fig. 3 is for being the adsorption curve that desorbing agent obtains with the normal butane.
Embodiment
Owing to be subjected to the restriction of thermodynamic(al)equilibrium, C
5～C
6Contain a certain amount of normal paraffin in the alkane isomerization product, this part normal paraffin octane value is lower, need be translated into the higher isoparaffin of octane value and just can obtain the high-octane rating blended gasoline.The present invention is with C
5～C
6The isomerization of paraffins product is the raw material of fractionation by adsorption, by liquid phase adsorption separation normal paraffin is wherein separated with isoparaffin, normal paraffin is carried out again isomerization reaction again, and so, fractionation by adsorption and isomerization reaction hocket, can be with C
5～C
6The whole isomerization of alkane, thus high-octane blended gasoline obtained.
For alleviating the load of fractionation by adsorption and isomerization reaction device, the present invention is earlier with C
5～C
6The alkane isomerization product feeds depentanizer and carries out rectifying, the active iso-pentane of non-isomerization in the raw material and other alkane separation are come out, iso-pentane is distillated by the depentanize cat head, a part is as irrigation flushing fractionation by adsorption post, all the other iso-pentane are discharged system, as the stop bracket gasoline blend component.The material of discharging at the bottom of the depentanizer is fed the fractionation by adsorption that the fractionation by adsorption post carries out normal paraffin and isoparaffin.
The operational condition of above-mentioned depentanizer is: 20～50 ℃ of tower top temperatures, 60～90 ℃ of tower still temperature, theoretical plate number are 40～60, account for 5～20 quality % of cat head distilled iso-pentane total amount as the iso-pentane of irrigation.Skellysolve A content is not more than 1.0 heavy % in the depentanizer distilled iso-pentane.
C
5～C
6After the alkane isomerization product enters the fractionation by adsorption post, sorbent material wherein is bigger to the adsorption rate of normal paraffin, that is to say, when reaching adsorption equilibrium, sorbent material is higher than adsorption selectivity to isoparaffin to the adsorption selectivity of normal paraffin, thereby after entering the fractionation by adsorption post, the normal paraffin in the raw material is adsorbed agent absorption prior to isoparaffin, and isoparaffin then flows out the fractionation by adsorption post as inhaling surplus liquid.Adsorb saturated after, the content of inhaling normal paraffin in the surplus liquid can increase gradually.The content that normal paraffin in the surplus liquid is inhaled in control among the present invention is less than 0.5 quality %, is about to inhale be considered as adsorbing state of saturation when normal paraffin content reaches 0.5 quality % in the surplus liquid.
After the fractionation by adsorption post reaches capacity, adsorb the space in the adsorption column, promptly contain a large amount of absorption raw materials in the dead volume, should wash adsorption column with irrigation earlier, the absorption raw material in the dead volume is carried out adsorption column, carry out desorption manipulation again.Flushing back gained washing fluid is an irrigation and the mixture of absorption raw material, and this mixture takes off the iso-pentane tower with entering after isomerization product mixes, with wherein iso-pentane with adsorb raw material and separate.
After absorption raw material in the fractionation by adsorption post was carried out adsorption column fully, flushing operation finished.Desorbing agent is fed the desorption that the fractionation by adsorption post carries out normal paraffin, and desorbing agent is with the C that adsorbs in the sorbent material
5, C
6Normal paraffin cements out, and forms desorption liquid.Desorption liquid is irrigation, desorbing agent and C
5, C
6The mixture of normal paraffin.Desorption liquid is sent into the desorption liquid knockout tower, and the cat head distilled iso-pentane of desorption liquid knockout tower is as fractionation by adsorption post washing fluid, and tower middle part side stream is C
5And C
6Normal paraffin removes the isomerization reaction device as the charging of isomerization reaction, and the distilled desorbing agent recycles at the bottom of the tower.
The inventive method is with C
5～C
6The alkane isomerization reaction product is the fractionation by adsorption raw material, and described raw material is the C of petroleum naphtha catalytic reforming or straight-run spirit
5～C
6The product that cut obtains after isomerization reaction, its boiling spread are 40～100 ℃, and wherein normal paraffin content is 20～50 quality %.
In the described method, during the fractionation by adsorption operation, the volume space velocity that raw material, irrigation and desorbing agent enter the fractionation by adsorption post is 0.5～4.0 o'clock-1, preferred 1.0～2.0 o'clock-1.
The relative desorption raw molecule of the desorbing agent that the inventive method is selected for use is the macromole normal paraffin, the mixture of the preferred normal heptane of described desorbing agent, octane or normal heptane and octane.
The present invention is used for the preferred 5A molecular sieve of sorbent material of fractionation by adsorption, and the sorbent material that loads in the fractionation by adsorption post is the 5A molecular sieve.
For guaranteeing the adsorption separation device continuous operation, generally adopt the multicolumn serial flow, absorption, flushing, desorption are replaced blocked operation.
Below in conjunction with Fig. 1 the inventive method is elaborated.For convenience of description, Fig. 1 is reduced to three with the fractionation by adsorption post, and during actually operating, each operating unit is 4～7 adsorption column series connection.
Among Fig. 1, isomerization reaction product is mainly C
5～C
6Alkane after condensation with the mixture of the washing fluid that comes by adsorption unit, under 20～40 ℃, enter depentanizer 1 by pipeline 11, depentanizer 1 tower top temperature is that 20～50 ℃, tower still temperature are that 60～90 ℃, theoretical plate number are 40～60, iso-pentane is discharged by depentanizer overhead line 14, and wherein Skellysolve A content is not more than 1.0 heavy %.An iso-pentane part that is obtained by the depentanizer cat head is circulated as the washing fluid of adsorption unit by pipeline 7, and remaining is discharged as the stop bracket gasoline blend component by pipeline 23.Taking off isomerization product behind the iso-pentane obtains at the bottom of by the depentanize Tata, this material is as the raw material of adsorption separation device, send into adsorption column 2 in the adsorption separation device by pipeline 13, after the 5A molecular sieve adsorption, gained is inhaled in the surplus liquid normal paraffin content less than 0.5 heavy % under 2.0～4.0MPa, 100～150 ℃, the condition of liquid phase.Inhale surplus liquid and send into the surplus liquid knockout tower 6 of suction by pipeline 15, separate by the desorbing agent that distillation will be inhaled in the surplus liquid, the overhead product of inhaling surplus liquid knockout tower 6 is an isoparaffin, by pipeline 16 discharge systems, directly remove the gasoline attemperation apparatus as the stop bracket gasoline blend component, inhaling at the bottom of the tower of surplus liquid knockout tower 6 is desorbing agent, and the desorption column 4 of being sent into adsorption unit by pipeline 17 recycles.After adsorption column 2 reaches adsorption equilibrium, contain a large amount of absorption raw materials in the adsorption column dead volume, the adsorption column 3 with the irrigation iso-pentane is introduced as the flushing post by pipeline 7 carries out absorption raw material wherein, and washing fluid is iso-pentane and the mixture that adsorbs raw material.This mixture is by pipeline 12 and C
5, C
6Enter after isomerization product mixes and take off iso-pentane tower 1.After absorption raw material in the adsorption column 3 was carried out adsorption column fully, flushing operation finished.Desorbing agent is fed in the desorption post 4 of adsorption unit by pipeline 18, the sorbent material that wherein has been rinsed is carried out desorption, the C that adsorbs on the sorbent material
5, C
6Normal paraffin replaces out, and desorption liquid is irrigation, desorbing agent and C
5, C
6The mixture of normal paraffin, desorption liquid is flowed out by adsorption column 4 bottoms, entering desorption liquid knockout tower 5 by pipeline 19 distills, the overhead product of desorption liquid knockout tower 5 is the irrigation iso-pentane, turn back to the overhead line 7 of the flushing post 3 of adsorption separation device by pipeline 20, desorption liquid knockout tower middle part side stream is C
5, C
6Normal paraffin by pipeline 21 discharge systems, enters the alkane isomerization reaction unit, and as the raw material of isomerization reaction, the bottom overhead product of desorption liquid knockout tower is a desorbing agent, and the desorption post that is turned back to adsorption separation device by pipeline 22 recycles.During above-mentioned technology is described, be convenient narration, adsorption column is divided into absorption, flushing, desorption three parts describes, in the actual mechanical process, whole fractionation by adsorption operates in that the order by absorption, flushing, desorption hockets between the adsorption column 2,3,4 in each adsorption column.
Further specify the present invention below by example, but the present invention is not limited to this.
Example 1
Taking by weighing 50 gram (butt) 5A molecular sieves (Nanjing, Nanjing catalyst plant) and pack in φ 10 * 250mm stainless steel adsorption column as sorbent material, is 42～98 ℃ C with boiling range
5, C
6The alkane isomerization product distills and takes off iso-pentane, the C before and after the depentanize
5, C
6Alkane isomerization product composition sees Table 1.Under 3.0MPa, 150 ℃, liquid-phase condition, will take off the C behind the iso-pentane
5, C
6The alkane isomerization product was by 1.0 o'clock
-1Volume space velocity feed adsorption column, carry out the fractionation by adsorption operation.Wait to adsorb saturated after, with the irrigation iso-pentane by 1.0 o'clock
-1Volume space velocity feed in the adsorption column, replace the absorption raw material in the adsorption column dead volume.Flushing is a desorbing agent with the octane after finishing, the normal paraffin that adsorbs in the desorption sorbent material hole, and the volume space velocity that desorbing agent feeds adsorption column is 1.0 o'clock
-1Get the desorption liquid point sample, measure the adsorption curve of desorbing agent on sorbent material, the adsorption curve of desorbing agent has reflected the desorption rate and the desorption ability of desorbing agent; The composition of desorption liquid adopts gas-chromatography (gas chromatograph is produced by Hewlett-Packard, and the trade mark is HP6890) analysis, the result as shown in Figure 2, the desorption liquid compound sample that each point is got is formed and is seen Table 2.
Comparative Examples
The method of pressing example 1 is to C
5, C
6The alkane isomerization product carries out fractionation by adsorption operation, and different is with the normal butane is desorbing agent, gets the desorption liquid point sample, desorbing agent adsorption curve such as Fig. 3 of recording.
By Fig. 2,3 as can be known, be that desorbing agent is compared with normal butane, be the desorption rate of desorbing agent obviously improves with the octane, desorbing agent reaches balance time on sorbent material obviously shortens, thereby is that desorbing agent can shorten the desorption manipulation cycle with macromolecular octane.In addition, form data as can be known by the desorption liquid of table 2, the content of octane accounts for about 73% of desorption liquid quality in desorption liquid, and desorbing agent proportion in desorption liquid is less, therefore, can reduce the yield of desorbing agent when desorption liquid Separation and Recovery desorbing agent.
Table 1
| The hydro carbons title | Content, quality % | |
| Before the depentanize | Behind the depentanize | |
| C 3 iC 4 nC 4 iC 5 nC 5 22DMB 23DMB 2MP 3MP nC 6 MCP | 0.455 1.886 0.359 33.364 16.628 9.406 4.706 13.844 8.438 8.03 0.430 | - - - 9.45 23.549 13.321 6.665 19.606 11.95 11.372 0.61 |
Table 2
| The hydro carbons title | Content, quality % |
| C 3 iC 4 nC 4 iC 5 nC 5 22DMB 23DMB 2MP 3MP nC 6 MCP nC 8 | - - 0.03 16.36 2.697 0.203 0.11 0.301 0.19 1.98 - 73.74 |
Annotate: in the table 1,2,22DMB is 2, and 2-dimethylbutane, 23DMB are 2, and 3-dimethylbutane, 2MP are the 2-methylpentane, and 3MP is the 2-methylpentane, and MCP is a methylcyclopentane.
Claims (9)
1, a kind of from C
5～C
6Separate the method for normal paraffin in the alkane isomerization product, comprise raw material C
5～C
6The alkane isomerization product feeds the fractionation by adsorption post, absorption normal paraffin wherein under 2.0～4.0MPa, 100～150 ℃, liquid-phase condition, wait to adsorb saturated after, be irrigation with the iso-pentane, the fractionation by adsorption post is washed, and then with C
7～C
9Normal paraffin be that desorbing agent carries out desorption to the fractionation by adsorption post, the sorbent material that loads in the described fractionation by adsorption post is the 5A molecular sieve.
2, in accordance with the method for claim 1, it is characterized in that earlier C
5～C
6The alkane isomerization product feeds depentanizer and carries out rectifying, and iso-pentane is distillated by the depentanize cat head, and a part is as irrigation flushing fractionation by adsorption post, and all the other iso-pentane are discharged system, and the material of discharging at the bottom of the depentanizer feeds the fractionation by adsorption post.
3, according to claim 1 or 2 described methods, it is characterized in that the surplus liquid distillation of the suction that the fractionation by adsorption post is discharged, separating isomerism alkane and desorbing agent are discharged system, desorbing agent recycle with the isoparaffin of gained.
4, according to claim 1 or 2 described methods, it is characterized in that the desorption liquid that obtains behind the desorption is sent into the desorption liquid knockout tower, the cat head distilled iso-pentane of desorption liquid knockout tower is as fractionation by adsorption post washing fluid, and tower middle part side stream is C
5～C
6Normal paraffin, the distilled desorbing agent recycles at the bottom of the tower.
5,, it is characterized in that the volume space velocity that described raw material, irrigation and desorbing agent enter the fractionation by adsorption post is at 0.5～4.0 o'clock according to claim 1 or 2 described methods
-1
6, in accordance with the method for claim 2, the operational condition that it is characterized in that depentanizer is that 20～50 ℃ of tower top temperatures, 60～90 ℃ of tower still temperature, theoretical plate number are 40～60, accounts for 5～20 quality % of cat head distilled iso-pentane total amount as the iso-pentane of irrigation.
7,, it is characterized in that described desorbing agent is normal heptane or octane according to claim 1 or 2 described methods.
8, according to claim 1 or 2 described methods, it is characterized in that described C
5～C
6The paraffin boiling points scope is 40～100 ℃, and wherein normal paraffin content is 20～50 quality %.
9, in accordance with the method for claim 1, it is characterized in that C
5～C
6The alkane isomerization product after fractionation by adsorption, from the fractionation by adsorption post in the surplus liquid of effusive suction the content of normal paraffin less than 0.5 quality %.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101497815B (en) * | 2008-01-31 | 2012-09-12 | 中国石油化工股份有限公司 | Isomerization method for light hydrocarbon |
| CN102452885B (en) * | 2010-10-25 | 2014-12-03 | 中国石油化工股份有限公司 | Adsorption and separation method of C5 and C6 isomerization product |
| CN103254932B (en) * | 2013-05-22 | 2015-12-23 | 南京工业大学 | Process for extracting C4-C6 normal paraffins and co-producing isopentane and isomeric hexane from light naphtha |
| CN106433742B (en) * | 2015-08-06 | 2018-07-31 | 中国石油化工股份有限公司 | A method of the adsorbing separation n-alkane from the distillate containing n-alkane |
| CN106833738B (en) * | 2015-12-03 | 2019-03-22 | 中国石油化工股份有限公司 | A kind of raising C5/C6The method of alkane octane number |
| CN106631670B (en) * | 2016-09-14 | 2019-05-21 | 南京康鑫成生物科技有限公司 | A method of obtaining isoparaffin from the positive isomery mixed alkanes of Long carbon chain |
| KR101944256B1 (en) * | 2018-03-28 | 2019-02-01 | 에스케이이노베이션 주식회사 | Method for separating normal-paraffin and iso-paraffin from hydrocarboneous oil |
| CN115505423B (en) * | 2021-06-22 | 2024-04-02 | 中国石油化工股份有限公司 | C (C) 5 ~C 6 Separation method of light hydrocarbon isomerisation product |
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