CN102372565A - Separation method used for preparing ethylene by ethanol dehydration - Google Patents
Separation method used for preparing ethylene by ethanol dehydration Download PDFInfo
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- CN102372565A CN102372565A CN2010102608013A CN201010260801A CN102372565A CN 102372565 A CN102372565 A CN 102372565A CN 2010102608013 A CN2010102608013 A CN 2010102608013A CN 201010260801 A CN201010260801 A CN 201010260801A CN 102372565 A CN102372565 A CN 102372565A
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Abstract
The invention relates to a separation method used for preparing ethylene by ethanol dehydration, which mainly solves the problems of low ethylene product purity and short device operation period during the production process flow of preparing ethylene by ethanol dehydration in prior art. According to the invention, the separation method used for preparing ethylene by ethanol dehydration uses a unique process and a structure of an alkaline tower as well as ingenious combination of a water scrubber and an ethylene rectifying tower for realizing the technical scheme to remove carbon dioxide, so that the problems can be better solved, and the present invention can be used for producing ethylene by ethanol dehydration in industrial production.
Description
Technical field
The present invention relates to a kind of separation method that is used for producing ethylene from dehydration of ethanol.
Background technology
Ethene is crucial petrochemical materials, and its large derived product mainly contains Vilaterm, oxyethane, terepthaloyl moietie, SE, vinylbenzene, vinyl acetate between to for plastic etc.
Production technique (the Gu Zhihua of existing ethylene prepared by catalytic dehydration of ethylene; The producing ethylene with ethyl alcohol state of the art and prospect [J]. chemical progress; 2006; 25 (8): production process 847-851) is: feed ethanol through preheater, vaporizer heating back all vaporization send the ethanol dehydration reaction system to react, after the reaction product (containing resultant of reaction ethene, water, unreacted ethanol etc.) of coming out from the dehydration reaction system is sent washing, scale to wash etc. to wash removal impurity; After compression, drying, get into ethylene rectification tower and carry out rectifying separation, obtain ethylene product from ethylene rectification tower top or cat head; And the ethanol of discharging from the tower still is sent to waste-water treatment tower with the mixed solution of components such as water together with the water wash column tower bottoms.
One of characteristics of existing method are to adopt soda-wash tower to remove the sour gas in the reaction product, but owing to material in the system that removes sour gas in the ethylene unit is dirtier, contain impurity such as some high boiling material and polymkeric substance, result in blockage easily.And the hypomere of existing alkali cleaning equipment does not have any inner member, forms the gas-liquid skewness easily herein, and it is undesirable to cause removing the sour gas effect; Not only cause final product purity lower; And, because the phenomenon of the stifled tower of soda-wash tower, cause in the soda-wash tower in the sour gas and not exclusively get into follow-up workshop section; With the operation that has a strong impact on follow-up tower, shorten the device operational cycle.
Summary of the invention
Technical problem to be solved by this invention is that ethylene product purity is low in the technological process of production of producing ethylene from dehydration of ethanol, and the problem that the device operational cycle is short provides a kind of method of new producing ethylene from dehydration of ethanol.This method has simple to operate, removes sour gas to greatest extent, guarantees the characteristics of product purity and device long-term operation.
In order to solve the problems of the technologies described above, the technical scheme that the present invention adopts is following: a kind of separation method that is used for producing ethylene from dehydration of ethanol may further comprise the steps:
1. contain ethene, ethanol water and other impurity reaction product and get into water wash column from the bottom, water gets into water wash column from top, discharges with unreacted ethanol and other impurity at the bottom of the washing Tata, obtains the logistics I at the water wash column top;
2. logistics I gets into soda-wash tower from the bottom, obtains the logistics II at the soda-wash tower top;
3. logistics II therefrom, the bottom gets into ethylene rectification tower, is the ethylene product of 90～99wt% from ethylene distillation column overhead extraction purity, and the ethylene distillation tower bottoms is discharged into subsequent handling.
In the technique scheme, because the temperature of reaction discharging is higher, preferred version is removed impurity such as ethanol, acetaldehyde for adopting water wash column to its washing and cooling; Water wash column adopts packing tower or tray column, and its theoretical plate number is 2～40; Logistics preferred version after the washing washs it for adopting soda-wash tower, removes acid gas impurities such as carbonic acid gas, and soda-wash tower adopts the biological ethane soda-wash tower; The crude ethylene that obtains after the alkali cleaning is sent into the middle and lower part of ethylene rectification tower; Pass back in the tower from the trim the top of column mouth from gas part after the ethylene condenser condensation of ethylene distillation column overhead extraction; The part that do not reflux is as the ethylene product extraction, and extraction purity is the ethylene product of 90～99wt%.The reflux ratio of ethylene rectification tower is 1.2～3.5, and the phegma temperature is-15～-60 ℃.Ethylene rectification tower adopts packing tower or tray column, and its theoretical plate number is 50～120, and wherein rectifying section is 20～85 blocks of theoretical trays, and tower top pressure is 0.6～4.0MPaG, and tower top temperature is-15～-50 ℃.
The present invention after reactor tail gas gets into hypomere, because the effect of inner member has produced a new gas distribution, has reduced the polymerization meeting of aldehydes owing to adopt special soda-wash tower.Because newly-increased inner member has the certain amount of fluid passage, therefore be difficult for being stopped up by polymeric impurities, obviously improved the stifled tower phenomenon in the full scale plant.Full scale plant is used proof, and the stifled tower phenomenon of soda-wash tower has reduced by 50% at least, has obtained better technical effect.
Description of drawings
Fig. 1 is the technical process of producing ethylene from dehydration of ethanol of the present invention.
Among Fig. 1,1 is washing water, and 2 are the reaction discharging, and 3 is water wash column; 4 is the water wash column overhead gas, and 5 is the water wash column tower bottoms, and 6 is soda-wash tower, and 7 is washing alkali liquid; 8 is the soda-wash tower overhead gas, and 9 is the soda-wash tower tower bottoms, and 10 is ethylene rectification tower, and 11 is the ethylene distillation tower bottoms; 12 is ethylene distillation cat head material, and 13 is ethylene distillation cat head condensing surface, and 14 for the ethylene distillation cat head refluxes, and 15 is ethylene product.
Through embodiment the present invention is done further elaboration below.
Embodiment
[embodiment 1]
Adopt technical process shown in Figure 1, vaporization carries that to heat up in a steamer the tower theoretical plate number be 20, working pressure 0.6MPa (G).Feed ethanol 2350kg/h, ethanol 1997.5kg/h wherein, water 352.5kg/h, ethanol content 85% (wt%).Ethylene rectification tower is a tray column; The operation table pressure pressure is 1.0MpaG.Feed ethanol is carried from vaporization and is heated up in a steamer the column overhead charging.Ethanol 66.08kg/h in the mixing kettle liquid of washing Tata still and ethylene distillation Tata still, water 1932kg/h, feed entrance point carry in vaporization and heat up in a steamer Tata and served as a fill-in the 8th theoretical stage place.The cat head exhaust vapour send the dehydration reaction system, wherein ethanol content 93.8% (wt%).Ethanol contains 0.05% (wt%) in the water that the tower still is discharged.
[embodiment 2]
The ethylene distillation tower top pressure is 1.78MPaG, and tower top temperature is-31 ℃, and tower still pressure is 1.81MPaG, and tower still temperature is 1 ℃, and the phegma temperature is-33 ℃.Ethanol 8.1kg/h in the charging, ethene 1290kg/h.Feed plate is at cat head number the 35th theoretical stage place.Overhead condensation liquid partial reflux is gone into tower, reflux ratio 2.0: 1, and part extraction ethylene product 1250kg/h, purity is 96% (wt%).Ethanol 7.9kg/h send vaporization to carry to heat up in a steamer tower and does raw material in the mixed solution that ethylene distillation Tata still is discharged.Vaporization carries that to heat up in a steamer tower be packing tower, and the worksheet pressure pressure is 1.0MpaG.
[embodiment 3]
The ethylene distillation tower top pressure is 1.78MPaG, and tower top temperature is-31 ℃, and tower still pressure is 1.81MPaG, and tower still temperature is 1 ℃, and the phegma temperature is-33 ℃.Ethanol 8.1kg/h in the charging, ethene 1290kg/h.Feed plate is at cat head number the 35th theoretical stage place.Overhead condensation liquid partial reflux is gone into tower, reflux ratio 2.0: 1, and part extraction ethylene product 1250kg/h, purity is 96% (wt%).Ethanol 7.9kg/h send vaporization to carry to heat up in a steamer tower and does raw material in the mixed solution 15 that ethylene distillation Tata still is discharged.Vaporization carries that to heat up in a steamer tower be packing tower, and the worksheet pressure pressure is 1.0MpaG.
[embodiment 4]
Vaporization carries that to heat up in a steamer the tower theoretical plate number be 30, operation table pressure pressure 0.9MPaG.Feed ethanol 2350kg/h, ethanol 2210kg/h wherein, water 140kg/h, ethanol content 94% (wt%).Feed ethanol is carried from vaporization and is heated up in a steamer the column overhead charging.Ethanol 76.25kg/h in the mixing kettle liquid of washing Tata still and ethylene distillation Tata still, water 1725kg//h, feed entrance point carry in vaporization and heat up in a steamer Tata and served as a fill-in the 21st theoretical stage place.The cat head exhaust vapour send the dehydration reaction system, ethanol 2286kg/h wherein, water 46.65kg/h, ethanol content 98% (wt%).Ethanol content 0.1% (wt%) in the water that the tower still is discharged.Ethylene rectification tower is a packing tower, operation table pressure pressure 1.5paG.
[embodiment 5]
Ethylene rectification tower operation table pressure pressure 0.9MpaG, tower top temperature-65 ℃, all number of theoretical plates are 82, ethanol 8.1kg/h in the charging, ethene 1290kg/h.Feed plate is at cat head number the 46th theoretical stage place.An overhead condensation liquid part is gone into tower from trim the top of column, and ethene is made in a part of extraction, reflux ratio 4: 1.Product 1250kg/h, purity is 99.00% (wt%).Ethanol 7.8kg/h send vaporization to carry to heat up in a steamer tower and does raw material in the mixed solution that ethylene distillation Tata still is discharged.Vaporization carries that to heat up in a steamer tower be tray column, and the operation table pressure pressure is 0.5MpaG.
[comparative example 1]
Feed ethanol 2350kg/h, ethanol 2210kg/h wherein, water 140kg/h, ethanol content 94% (wt%).Get into reactive system behind the feed ethanol process ethanol evaporation device.Water wash column is a packing tower, and operation table pressure pressure 0.1MPaG. ethylene rectification tower is a packing tower, operation table pressure pressure 1.8MPaG. washing Tata still ethanol 58.01kg/h, water 1925kg/h, ethylene distillation Tata still ethanol 8.1kg/h.
Claims (7)
1. separation method that is used for producing ethylene from dehydration of ethanol may further comprise the steps:
1. contain ethene, ethanol water and other impurity reaction product and get into water wash column from the bottom, water gets into water wash column from top, discharges with unreacted ethanol and other impurity at the bottom of the washing Tata, obtains the logistics I at the water wash column top;
2. logistics I gets into soda-wash tower from the bottom, obtains the logistics II at the soda-wash tower top;
3. logistics II therefrom, the bottom gets into ethylene rectification tower, is the ethylene product of 90～99wt% from ethylene distillation column overhead extraction purity, and the ethylene distillation tower bottoms is discharged into subsequent handling.
2. the separation method that is used for producing ethylene from dehydration of ethanol according to claim 1 is characterized in that said water wash column removal ethanol, acetaldehyde impurities.
3. the separation method that is used for producing ethylene from dehydration of ethanol according to claim 1 is characterized in that said water wash column adopts packing tower or tray column, and its theoretical plate number is 2～40.
4. the separation method that is used for producing ethylene from dehydration of ethanol according to claim 1 is characterized in that acid gas impurities such as said soda-wash tower removal carbonic acid gas.
5. the separation method that is used for producing ethylene from dehydration of ethanol according to claim 1 is characterized in that said soda-wash tower adopts the biological ethane soda-wash tower.
6. the separation method that is used for producing ethylene from dehydration of ethanol according to claim 1; It is characterized in that the crude ethylene that after alkali cleaning, obtains sends into the middle and lower part of ethylene rectification tower; Pass back in the tower from the trim the top of column mouth from gas part after the ethylene condenser condensation of ethylene distillation column overhead extraction; The part that do not reflux is as the ethylene product extraction, and extraction purity is the ethylene product of 90～99wt%; Reflux ratio is 1.2～3.5, and the phegma temperature is-15～-60 ℃.
7. the separation method that is used for producing ethylene from dehydration of ethanol according to claim 1; It is characterized in that ethylene rectification tower adopts packing tower or tray column; Its theoretical plate number is 50～120; Wherein rectifying section is 20～85 blocks of theoretical trays, and tower top pressure is 0.6～4.0MPaG, and tower top temperature is-15～-50 ℃.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103539605A (en) * | 2012-07-12 | 2014-01-29 | 中国石油化工股份有限公司 | Separation method for preparing ethylene through ethanol dehydration |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101007283A (en) * | 2007-01-26 | 2007-08-01 | 江苏工业学院 | ZSM-5 molecular sieve modified catalyst and its preparation method and application |
| CN101134704A (en) * | 2007-10-16 | 2008-03-05 | 南京工业大学 | Process for producing ethylene by ethanol dehydration |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101007283A (en) * | 2007-01-26 | 2007-08-01 | 江苏工业学院 | ZSM-5 molecular sieve modified catalyst and its preparation method and application |
| CN101134704A (en) * | 2007-10-16 | 2008-03-05 | 南京工业大学 | Process for producing ethylene by ethanol dehydration |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103539605A (en) * | 2012-07-12 | 2014-01-29 | 中国石油化工股份有限公司 | Separation method for preparing ethylene through ethanol dehydration |
| CN103539605B (en) * | 2012-07-12 | 2015-12-16 | 中国石油化工股份有限公司 | The separation method of producing ethylene from dehydration of ethanol |
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Application publication date: 20120314 |