CN102690159A - Method for preparing isobutene by dehydration of low-concentration tert butyl alcohol - Google Patents
Method for preparing isobutene by dehydration of low-concentration tert butyl alcohol Download PDFInfo
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- CN102690159A CN102690159A CN2011100708488A CN201110070848A CN102690159A CN 102690159 A CN102690159 A CN 102690159A CN 2011100708488 A CN2011100708488 A CN 2011100708488A CN 201110070848 A CN201110070848 A CN 201110070848A CN 102690159 A CN102690159 A CN 102690159A
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Abstract
A method for preparing isobutene from low-concentration tert butyl alcohol. The method is characterized in that a rectifying tower is employed to separate tert butyl alcohol; a tert butyl alcohol-water mixture similar to azeotropic composition directly from side-draw enters into a fixed bed reactor; and the reaction products return to the rectifying tower. A tower top condenser of the rectifying tower is a partial condenser; the liquid phase is basically in infinite reflux state, and only a small amount of the liquid phase is recovered, so as to prevent enrichment of C8 by-product in the tower. A vapour recovery isobutene product is treated with cryogenic treatment and converted into a liquid-phase isobutene product; and another product is recovered by the tower bottom. The rectifying tower and the reactor in the invention form a system, and operation of rectifying tower is adjusted to realize complete reaction of tert butyl alcohol and product separation; and water is recovered by the tower bottom, and the isobutene product with high purity is obtained by the tower top. The method has advantages of small equipment investment, convenient catalyst filling, low energy consumption, operation easiness and high product purity of isobutene.
Description
Technical field
The present invention relates to the method that a kind of trimethyl carbinol dehydration prepares iso-butylene, be specifically related to a kind of method that adopts the high-purity iso-butylene of lower concentration trimethyl carbinol dehydration preparation.
Background technology
Iso-butylene is a kind of important basic Organic Chemicals.Trimethyl carbinol evaporation is the important channel that obtains high-purity isobutylene, and this method side reaction is few, and quality product is high, reduced investment.The patent of trimethyl carbinol dehydration preparing isobutene is a lot, and US3665048 adopts fixed-bed process, and aluminum oxide is a catalyzer; Be reflected in the vapour phase and carry out, US5849971 adopts catalytic rectification process to produce iso-butylene, and CN200710049954.1 adopts intermittently tank reactor production iso-butylene; CN1609082A has introduced and has a kind ofly prepared the method for iso-butylene by the trimethyl carbinol, adopts fixed-bed reactor, is reflected in the liquid phase and carries out; Reaction product gets into primary fractionator, pressurized operation, and the liquid-phase product of iso-butylene is rich in the cat head extraction; Get into the iso-butylene treating tower, obtain the iso-butylene product at the bottom of the tower.The primary fractionator bottom product is introduced into a rectifying tower, removed overhead carbon eight by-products, and bottom product gets into another rectifying tower, and tower still recovered water, cat head are that the tertiary butanol and water mixture that nearly azeotropic is formed returns fixed-bed reactor.US4208540 has introduced by the mixed c 4 hydration and has generated the trimethyl carbinol, the method that iso-butylene is produced in trimethyl carbinol dehydration, and tank reactor or fluidized-bed reactor are adopted in trimethyl carbinol dehydration; Vapour phase iso-butylene product is carried entering product purification towers such as the trimethyl carbinol secretly; Cat head extraction iso-butylene product, bottom product gets into another treating tower, removed overhead carbon eight by-products; Bottom product gets into follow-up rectifying tower; The liquid-phase product of reactor drum extraction also gets into follow-up rectifying tower, and recovered water at the bottom of the tower returns dehydration reactor behind the nearly azeotropic t-butanol-water mixture of cat head extraction.These two kinds of methods are all paid close attention to the iso-butylene product separation, are separated obtaining the iso-butylene product by one or two rectifying tower, but all use two rectifying tower to realize the recovery of trimethyl carbinol azeotropic mixture, and the separating of by-product carbon eight and water, the equipment input is many, and energy consumption is big.
External trimethyl carbinol main source is Trimethylmethane and propylene co-oxidation production propylene oxide process, and the amount of the coproduction trimethyl carbinol is very big.And domesticly there is not this type full scale plant; The trimethyl carbinol is mainly derived from iso-butylene hydration technology, because the hydration reaction isobutene conversion is lower, and the water oil volume is bigger; The mass content of the trimethyl carbinol is no more than 15% in the trimethyl carbinol aqueous solution that generates; Generally all need be with its rectification process, after cat head obtains the t-butanol solution of mass content about 85%, carry out dehydration reaction with this nearly azeotropic solution again.Because the trimethyl carbinol and water are azeotropic systems, generally all more than 4, energy consumption is bigger for the reflux ratio of rectifying.In the process of trimethyl carbinol dehydration,, therefore also need increase a rectifying tower again and t-butanol solution carried dense because the concentration of the trimethyl carbinol constantly reduces.
Summary of the invention
The method that the object of the present invention is to provide a kind of lower concentration t-butanol solution dehydration to produce iso-butylene, this method less equipment investment, energy consumption is low, easy handling.
The present invention realizes through following technical scheme: a kind of lower concentration trimethyl carbinol dehydration prepares the method for iso-butylene; Comprise that mass concentration is that 5%～15% t-butanol solution gets into the rectifying tower bottom and separates; Tower still recovered water; Overhead product gets into a partial condenser, and the mass percent that partial condenser liquid phase produced quantity accounts for the raw material inlet amount is 0.05%～5%, all the other backflows; Another condensing surface of vapour phase extraction iso-butylene product entering carries out condensation and obtains liquid phase iso-butylene product; It is characterized in that the tertiary butanol and water mixture that the extraction of rectifying tower side line is formed near azeotropic gets in the fixed-bed reactor, the extraction position is the 2nd～8 theoretical stage of rectifying tower, and the reaction product of fixed-bed reactor is returned the rectifying tower middle part again and separated.
Fixed-bed reactor pressure of the present invention is 0.4～2MPa, and temperature of reaction is 50～110 ℃.
Fixed-bed reactor of the present invention are not limited to a reactor drum, can be a plurality of reactor drum polyphones or parallel connection.
The working pressure of rectifying tower of the present invention is 0.08～0.3MPa.
The partial condenser temperature of rectifying tower cat head of the present invention is controlled at-20～30 ℃.
Load azochlorosulfonate acid resin catalyst in the fixed-bed reactor of the present invention.
Lower concentration trimethyl carbinol raw material of the present invention is from iso-butylene hydrating process in the mixed c 4; Use " rectifying-reaction " systems produce iso-butylene that rectifying tower and fixed-bed reactor are formed; The rectifying tower side line is extracted the t-butanol solution entering fixed-bed reactor that nearly azeotropic is formed, vapour phase extraction iso-butylene product out.Use this system, the lower concentration trimethyl carbinol need not rectifying tower of extra increase and trimethyl carbinol concentration is carried dense, and the trimethyl carbinol that the nearly azeotropic of side line extraction is formed gets into fixed-bed reactor does not need heat exchange can reach the needed temperature of reaction.The liquid-phase product of a small amount of extraction of cat head, in order that do not make the enrichment in tower of carbon eight by-products, be the diisobutylene and the trimethyl carbinol main the composition in this liquid-phase product, octane value is very high, can be used as the additive of gasoline through processed.
Adopt the inventive method, less equipment investment, catalyst filling is convenient, and energy consumption is low, easy handling, the iso-butylene product purity is high.
Description of drawings
Fig. 1 is a schematic flow sheet of the present invention.
A-rectifying tower among the figure, b-fixed-bed reactor, c-partial condenser, d-condensing surface, e-reboiler; 1-lower concentration trimethyl carbinol raw material, 2-side line extraction material, 3-fixed bed reaction product, 4-cat head liquid-phase reflux, 5-cat head vapour phase iso-butylene product, 6-cat head liquid phase production material, 7-liquid phase iso-butylene product, the discharging of 8-tower still.
Embodiment
Further describe below in conjunction with 1 pair of the inventive method of accompanying drawing.The trimethyl carbinol raw material 1 of lower concentration gets into the middle and lower part of rectifying tower a, and theoretical number of plates of rectifying tower is 10～50, and working pressure is 0.08～0.3MPa, and rectifying tower dephlegmator of top of the tower c temperature is controlled at-20～30 ℃; The trimethyl carbinol material 2 that the nearly azeotropic of side line extraction is formed gets into fixed-bed reactor b, and the extraction position is the 2nd～8 theoretical stage of rectifying tower, and produced quantity is confirmed according to the trimethyl carbinol transformation efficiency of fixed-bed reactor; The pressure-controlling of fixed-bed reactor is at 0.4～2MPa; Temperature of reaction is controlled at 50～110 ℃, and reaction product 3 is returned the middle part of rectifying tower a, and the main composition of product 3 is iso-butylenes; The trimethyl carbinol and water contain a spot of carbon eight by-products; The rectifying tower overhead product gets into partial condenser c; The liquid phase stream 4 that partial condenser c condensation is got off refluxes, and logistics 6 is as the by product extraction, and the main composition of logistics 6 is the trimethyl carbinol and carbon eight; Contain a spot of iso-butylene and water; The mass percent that produced quantity accounts for the raw material inlet amount is 0.05%～5%, the vapor phase product extraction iso-butylene product 5 of partial condenser c, and iso-butylene 5 is condensed into liquid phase iso-butylene product 7 behind condensing surface d deep cooling; Rectifying Tata still extraction logistics 8, be water main the composition.
Embodiment 1
Mass content is 15% trimethyl carbinol raw material 1 entering rectifying tower a, and rectifying tower a has 16 theoretical stages, and feed entrance point is the 12nd theoretical stage; Working pressure 0.12MPa, the temperature of dephlegmator of top of the tower c is 5 ℃, side line material 2 picks up from the 3rd theoretical stage; Get into fixed-bed reactor b, 85 ℃ of temperature of reaction, reaction pressure 1MPa; Reaction product 3 is returned the 10th theoretical stage of rectifying tower a, and vapour phase extraction iso-butylene product 5 is condensed into liquid-phase product 7 behind condensing surface d deep cooling; The liquid phase of partial condenser condensation is mainly returned stream, a small amount of extraction liquid phase material 6, tower still extraction logistics 8.Concrete logistics flux and composition are seen table 1.
Table 1
Embodiment 2
The trimethyl carbinol raw material 1 of mass content 5% gets into rectifying tower a, and rectifying tower a has 50 theoretical stages, and feed entrance point is the 30th theoretical stage; Working pressure 0.3MPa, the temperature of dephlegmator of top of the tower c is 29 ℃, side line material 2 picks up from the 6th theoretical stage; Get into fixed-bed reactor b, 60 ℃ of temperature of reaction, reaction pressure 1.5MPa; Reaction product 3 is returned the 25th theoretical stage of rectifying tower a, and vapour phase extraction iso-butylene product 5 is condensed into liquid-phase product 7 behind condensing surface d deep cooling; The liquid phase of partial condenser condensation is mainly returned stream, a small amount of extraction liquid phase material 6, tower still extraction logistics 8.Concrete logistics flux and composition are seen table 2.
Table 2
Embodiment 3
The trimethyl carbinol raw material 1 of mass content 10% gets into rectifying tower a, and rectifying tower a has 30 theoretical stages, and feed entrance point is the 15th theoretical stage; Working pressure 0.08MPa, the temperature of dephlegmator of top of the tower c is-5 ℃, side line material 2 picks up from the 3rd theoretical stage; Get into fixed-bed reactor b, 95 ℃ of temperature of reaction, reaction pressure 0.5MPa; Reaction product 3 is returned the 14th theoretical stage of rectifying tower a, and vapour phase extraction iso-butylene product 5 is condensed into liquid-phase product 7 behind condensing surface d deep cooling; The liquid phase of partial condenser condensation is mainly returned stream, a small amount of extraction liquid phase material 6, tower still extraction logistics 8.Concrete logistics flux and composition are seen table 3.
Table 3
Claims (6)
1. lower concentration trimethyl carbinol dehydration prepares the method for iso-butylene; Comprise that mass concentration is that 5%～15% t-butanol solution gets into the rectifying tower bottom and separates; Tower still recovered water; Overhead product gets into a partial condenser, and the mass percent that partial condenser liquid phase produced quantity accounts for the raw material inlet amount is 0.05%～5%, all the other backflows; Another condensing surface of vapour phase extraction iso-butylene product entering carries out condensation and obtains liquid phase iso-butylene product; It is characterized in that the tertiary butanol and water mixture that the extraction of rectifying tower side line is formed near azeotropic gets in the fixed-bed reactor, the extraction position is the 2nd～8 theoretical stage of rectifying tower, and the reaction product of fixed-bed reactor is returned the rectifying tower middle part again and separated.
2. the method for claim 1 is characterized in that described fixed-bed reactor pressure is 0.4～2MPa, and temperature of reaction is 50～110 ℃.
3. the method for claim 1 is characterized in that described fixed-bed reactor are a plurality of reactor drum polyphones or parallel connection.
4. the method for claim 1, the working pressure that it is characterized in that described rectifying tower is 0.08～0.3MPa.
5. the method for claim 1 is characterized in that the partial condenser temperature of described rectifying tower cat head is controlled at-20～30 ℃.
6. the method for claim 1 is characterized in that loading azochlorosulfonate acid resin catalyst in the described fixed-bed reactor.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2011100708488A CN102690159A (en) | 2011-03-23 | 2011-03-23 | Method for preparing isobutene by dehydration of low-concentration tert butyl alcohol |
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| CN2011100708488A CN102690159A (en) | 2011-03-23 | 2011-03-23 | Method for preparing isobutene by dehydration of low-concentration tert butyl alcohol |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105175211A (en) * | 2015-10-10 | 2015-12-23 | 中建安装工程有限公司 | Device and method for preparing high-purity isobutene through tert-butyl alcohol dehydration by means of catalytic distillation structured packing |
| CN111635290A (en) * | 2020-07-03 | 2020-09-08 | 天津科技大学 | Method for preparing isobutene by dehydration of tertiary butanol |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4423271A (en) * | 1981-12-24 | 1983-12-27 | Chemische Werke Huls Ag | Process for producing high purity isobutene by dehydrating tertiary butanol |
| US5625109A (en) * | 1994-11-21 | 1997-04-29 | Gupta; Vijai P. | Liquid phase dehydration of tertiary butyl alcohol |
| CN101381273A (en) * | 2007-09-06 | 2009-03-11 | 四川古杉油脂化学有限公司 | Method for preparing isobutene by tert-butanol and apparatus |
-
2011
- 2011-03-23 CN CN2011100708488A patent/CN102690159A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4423271A (en) * | 1981-12-24 | 1983-12-27 | Chemische Werke Huls Ag | Process for producing high purity isobutene by dehydrating tertiary butanol |
| US5625109A (en) * | 1994-11-21 | 1997-04-29 | Gupta; Vijai P. | Liquid phase dehydration of tertiary butyl alcohol |
| CN101381273A (en) * | 2007-09-06 | 2009-03-11 | 四川古杉油脂化学有限公司 | Method for preparing isobutene by tert-butanol and apparatus |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105175211A (en) * | 2015-10-10 | 2015-12-23 | 中建安装工程有限公司 | Device and method for preparing high-purity isobutene through tert-butyl alcohol dehydration by means of catalytic distillation structured packing |
| CN105175211B (en) * | 2015-10-10 | 2017-03-22 | 中建安装工程有限公司 | Device and method for preparing high-purity isobutene through tert-butyl alcohol dehydration by means of catalytic distillation structured packing |
| CN111635290A (en) * | 2020-07-03 | 2020-09-08 | 天津科技大学 | Method for preparing isobutene by dehydration of tertiary butanol |
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Application publication date: 20120926 |