Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1991-11-26
1993-02-09
Evans, Joseph E.
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C07C 2986, C07C 3108
Patent
active
051854813
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to a method for the separation of impurities from a crude ethanol aqueous solution and, more particularly, to a method for removing impurities from an ethanol aqueous solution producible, for example, by fermentation.
2. Background Art
Ethanol is producible by fermentation of sugars such as molasses and so on or by hydration of ethylene (the two methods may hereinafter be referred to as fermentation method or synthesis method, respectively). Ethanol producible from the fermentation method and synthesis method is a crude ethanol aqueous solution in which a variety of impurities is contaminated. Main impurities contained in the crude ethanol aqueous solution obtainable by the fermentation method include methanol, acetaldehyde, n-propanol, n-butanol, ethyl acetate, 3-methylbutanol, and so on, and a large number of impurities is contained therein.
On the other hand, main impurities contained in the crude ethanol aqueous solution obtainable by the synthesis method include acetaldehyde, diethyl ether, acetone, secondary butanol, n-butanol, crotonaldehyde, etc. Likewise, this crude ethanol aqueous solution contains many kinds of impurities.
The impurities contained in the crude ethanol aqueous solution is so large in number of kinds, as described hereinabove, and so small in quantity that it is very difficult to remove them.
The crude ethanol aqueous solution containing such a large number of the impurities as described hereinabove is generally purified by distillation method.
This treatment uses a number of distillation towers and consumes a large quantity of steam for distillation. At least one of the distillation towers is operated by extraction and distillation system, in which a large quantity of water is added again to ethanol which has once been distilled and concentrated and the resulting mixture is then fed to the other distillation tower for treatment. Hence, conventional method for the purification of ethanol is extremely poor in energy efficiency.
In order to improve the problem with energy efficiency as recognized for the distillation method as described hereinabove, Japanese Patent Laid-open Publication (kokai) No. 41,627/1985 proposes the method for purifying crude ethanol by using carbon dioxide in a liquid state or in a supercritical state.
This method adopts processes removing carbon dioxide and diluting with water for recovering ethanol entrained in the carbon dioxide gases, together with impurities. This method, however, requires operation of separating an organic phase from an aqueous phase and operation of elevating pressures for recirculation of the aqueous solution. Further, this method is found insufficient in the recovery of ethanol.
On the other hand, the present inventors have proposed a method for purification and concentration by carrying out two-step extraction of a crude ethanol aqueous solution producible by the fermentation method with carbon dioxide in a liquid state or in a supercritical state, as disclosed in Japanese Patent Application No. 199,800/1988. This method, however, does not yet reach a sufficient level of purification.
The object of the present invention is to provide an efficient method for the purification of ethanol, which can solve the defects as seen in the conventional technology.
DISCLOSURE OF INVENTION
It is known that, when a crude ethanol aqueous solution is extracted with carbon dioxide in a liquid state under high pressures or with carbon dioxide in a supercritical state, a rate at which lipophilic impurities in the crude ethanol aqueous solution are extracted increases as a ratio of the weight of an extracting solvent (i.e. a ratio of the weight of the extracting solvent to the weight of a crude ethanol aqueous solution; this ratio may hereinafter be referred to merely as an extracting solvent ratio) increases, and a substantially entire quantity of the lipophilic impuritiesis extracted and transferred to an extract phase, when the extracting agent ratio is larger than a certain value. The
REFERENCES:
patent: 4769112 (1988-09-01), Wheldon
patent: 4842693 (1989-06-01), Wheldon
De Filippi et al., Biotechnol. Bioeng. Symp. Dec. 1982, (Symp. Biotechnol. Energy Prod. Conserv. 4th) pp. 205-219.
Chemical Abstracts, 98 (14) 109269v (1983) *abstract*.
Hirohama Seiya
Kanegae Futoshi
Muto Tsunehisa
Ojiro Masazumi
Takatsuka Toru
Evans Joseph E.
Japan as represented by Ministry of International Trade and Indu
LandOfFree
Method for the separation of impurities from crude ethanol aqueo does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for the separation of impurities from crude ethanol aqueo, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for the separation of impurities from crude ethanol aqueo will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-326651