United States Patent [191
[11]
4,251,231
Baird
[45]
Feb. 17, 1981
[54] DIRECT PROCESS FOR THE PRODUCI‘ION
OF GASOHOL FROM FERMENTATION
MIXTURES
[75] Inventor:
[73} Assignee:
James L. Baird, Winchester, Mass.
Artisan Industries Inc., Waltham,
Mass.
2,012,199
8/1935
2,182,550
12/1939
2,371,010
2,591,672
3/1945
4/1952
McElroy ................................ .. 44/56
Christensen ..
44/53
Wolfner ...... ..
44/56
Cattcrall ............................... .. 203/18
Primary Examiner—Jacqueline V. Howard
Attorney, Agent, or Firm-Richard P. Crowley
[57]
ABSTRACT
[21] Appl. No.: 75,012
[22] Filed:
Sep. 13, 1979
A process for the direct preparation of a gasohol from a
low-content, water-alcohol solution of a fermentation
broth, which solution contains ethanol or methanol,
[51]
Int. Cl.3 .................................. .. C10L l/02
which process comprises mixing a low-volume alcohol
[52]
U.S. Cl. ......................................... .. 44/56; 44/53;
44/77
[58]
Field of Search ....................... .. 44/53, 54, 56, 77;
203/18, 19
[56]
References Cited
solution, a solvent miscible in the alcohol and in the
gasoline and a gasoline; discarding essentially alcohol
free water and recovering a gasohol composition of
about 8% to 15% by volume of combined alcohol and
solvent; removing water of saturation from the gasohol;
and recovering substantially anhydrous gasohol.
U.S. PATENT DOCUMENTS
1,937,786
12/1933
Ricard et a1. ........................ .. 203/19
22 Claims, No Drawings
4,251,231
1
2
direct liquid-liquid mixing and extracting of methanol
DIRECT PROCESS FoR THE PRODUCTION or
GASOHOL FROM FERMENTATION. MIXTURES
‘BACKGROUND OF THE INvENTIoN
or ethanol, or mixtures thereof, from a fermentation
broth, by the employment of a gasoline or gasoline-type
product, are not directly possible, due to the substan
5 tially reduced solubility of the ethanol or methanol in
the gasoline during the alcohol, water and gasoline
Gasohol has been suggested widely as a substitute for
liquid-liquid extraction process.
I
I
gasoline and for combustion in internal-combustion
I- have discovered, however, that gasohol may be
engines. Typically,'gasohol compr‘ises'a mixture of‘ an
prepared directly from fermentation broths or low
hydrous alcohol and gasoline, with the alcohol present
in an amount sufficient to be soluble in'the' gasoline. 10 .volume alcohol-water solutions employing gasoline as a
solvent in a liquid-liquid mixing and extracting process,
More particularly, gasohol is typically a mixture of
when the gasolinecomposition or the water-alcohol
approximately 6% to' 12% by weight of alcohol; typi
‘solution contains a small, but effective, amount of a
cally’methanol or ethanol, and gasoline. The'gasoho'l
‘solvent, which increases the solubility of the alcohol of
the fermentation broth in the gasoline composition,
therefore making feasible the savings of distillation en
may contain other suitable additives, such as leaded or
other antiknock additives, and, where applicable, sur
factants, detergents, octane enhancers-and promoters,
such as tertiary methylbutyl ethyl ether and other addi
ergy ordirect extraction of methanol or ethanol from a
tives, employed to enhance the combustion and perfor
fermentation broth.
I have discovered that a suitable gasoline composi
mance of gasoline.
.
In the production of gasohol, substantially anhydrous
tion, for use in direct extraction of ethanol or methanol
from a fermentation broth, comprises a gasoline, such as
alcohol is required for admixture with the gasoline,
because of the very low water tolerance of the resulting
gasohol mixture. This water tolerance often is in the
a naphtha, straight-run-type, 'unblended organic gaso
line which may contain a small, but effective, amount of
range of approximately 0.2 to 0.5 weight percent of
an alcohol solvent or an alcohoi-misiclbe liquid therein,
water. Higher amounts of water typically provide for 25 such as, for example, an alcohol like a C3-C6 alcohol;
unstable gasohol mixtures and lead to complete or par
for example, a butanol, amyl alcohol, hexanol or combi
tial separation of the water from the gasoline, the water
nations thereof, which are soluble in the gasoline. Typi
being soluble in vthe methanol or ethanol, but insoluble
cally, the amount of the solvent to be employed in the
in the gasoline, whether the gasoline is composed of
gasoline ranges from about 0.1% to 5% of the gasoline;
highly aromatic or aliphatic components or a combina 30 for example, 0.5% to 3% of the gasoline by weight.
tion thereof;
1
The solvent, such as the alcohol, may be added di
Alcohols suitable for use in gasohol, particularly
rectly to a low alcohol-water solution or to the gasoline
methanol and ethanol, are commonly made by the fer
or to the ethanol to be extracted from the broth. The
mentation of various materials, such as sugar, corn and
solvent may include, besides an alcohol, such other
other grain-like or natural, fermentable materials. Fer 35 liquid organic combustion materials miscible with the
mentation broths or solutions produced often will con
ethanol or methanol, such as low-molecular-weight,
tain up to approximately 12% alcohol in- water; :for
volatile ethers, esters and ketones, but preferably and
example, 3% to 10%. The alcohol is separated from the
suitably
is a. lower, easily combustible, C34C6 alcohol.
water in the fermentation broth usually by a distillation
Where‘.
an
alcohol is employed, the butyl or amyl or
process, which consumes alarge amount of thermal 40.
other alcohols may be extracted from a fermentation
‘energy. The production of anhydrous ethanol. in partic
broth; employing the gasoline, and then the solvent
alcohol contained in the gasoline composition then is
ular requires an additional distillation step often‘ utiliz
ing an entraining or dehydrating solvent,- such as ben
employed in direct extraction of the methanol or etha
zene or other suitable liquid, to form a ternary solution.
The addition of the benzene ‘or other liquid is required, 45 nol from a suitable fermentation broth. In effect, my
process provides in substance for shifting the plait
since ethanol and water form an azeotrope of approxi
points and shift‘mg the operating line of a temary-phase
mately 95% alcohol and.5% water. The addition of
diagram composed of alcohol-water-gasoline, to pro
benzene is required to permit the preparation. of an
vide gasohol with water therein. If desired, rather than
anhydrous ethanol.
~ It would be most desirable to provide for the direct 50 using a. miscible solvent, this shift may be accomplished
by increasing the ionic strength of the water and reduc
preparation of a gasohol from a fermentation broth and
ing the solubility of the water through the use of addi
without the use of large amounts of thermal energy, as
tives, such as water-soluble salts like sodium chloride.
required in distillation, or the formation of azeotropes,
- Thus, my process comprises the direct preparation of
with the need to add dehydrating solvents.
SUMMARY OF THE INVENTION
My invention is directed to a direct'method for the
production of gasohol and to the gasohol produced
thereby. In particular, my invention relates to the direct
production of substantially anhydrous gasohol suitable
for combustion in internal-combustion engines from a
fermentatiombroth solution containing methanol or
ethanol or admixtures thereof.
My invention involves the saving of considerable
amounts of thermal energy by the direct extraction of
the alcohol suitable for use in gasohol from a fermenta
tion mixture by employing a gasoline as a-solvent mix
ture in a liquid-liquid extraction process. However, the
SS
asubstantially anhydrous gasohol; that is, gasoline con
taining methanol or ethanol or combinations thereof,
with perhaps slight traces of other alcohols, from a
fermentation broth containing the alcohols, and which
process comprises, firstly, mixing and extracting the
60 alcohol from the fermentation broth by employing, in a
liquid-liquid extraction process, a gasoline composition
which contains a solvent, which solvent increases the
solubility of the methanol or ethanol in the gasoline
composition, or preferably the additive alcohol is intro
duced with the weak ethanol of the broth, thereby per
mitting the direct extraction of the ethanol or methanol
from the fermentation broth or mixture by the gasoline
composition. Thereafter, a substantially anhydrous
4,251,231
3
gasohol may be produced by removing whatever water
of saturation occurs in the resulting extracted alcohol
gasoline composition product.
'
4
(b) removing from the extraction process an essen
‘ tially alcohol-free water;
i
(c) removing a gasohol composition containing water
I
of saturation, which composition contains from up
to about 15% by volume of combined alcohol;
Removal of the water of saturation may be accom
plished in a number of ways, such as the use of water
adsorbents or absorbents, but preferably is accom
(d) removing at least some of the water of saturation
plished by reducing the temperature of the extracted
alcohol-gasoline product utilizing typical heat
from the gasohol composition; and
(e) recovering a substantially anhydrousgasohol.
exchange equipment to reduce the temperature to the
level desired; for example, to below about —l0° R,
prises from about 0.5% to 3% by weight of the gasoline
such as below —30° F. or .—40'’ F., thereby substan
‘of a C3 to C6 aliphatic alcohol.
2. The process of claim 1 wherein the solvent com
3. The process of claim 2 wherein the. organic alcohol
tially reducing the water of saturation in the mixture
is selected from the group consisting of isopropyl alco
and then decanting or otherwise removing the water ‘of
hol, butyl alcohol, amyl alcohol, hexanol and combina
saturation from the gasohol and recovering a substan
15 tions thereof.
tially anhydrous gasohol.
A
4. The process of claim 1 wherein the water of satura
My process, therefore, avoids the formation of azeo
tion is removed by employing water adsorbents.
tropes and the use of large amounts of thermal energy
5. The process of claim 1 wherein the water of satura
and distillation steps and simpli?es the number of steps
tion is removed by chilling the gasohol composition to
involved and permits direct preparation of a substan
tially anhydrous gasohol directly from an alcohol-con 20 a low temperature to reduce the solubility of the water
of saturation and, thereafter, removing the water of
taining fermentation broth.
saturation.
.
My process will be described for the. purposes of
6. The process of claim 5 wherein the water of satura
illustration only in its preferred embodiment; however,
tion is removed by decanting the water of saturation
it is recognized that various changes and modi?cations
may be made to the process by those persons skilled in 25 from the chilled gasohol composition.
7. The process of claim 5 which includes chilling the
the art, all fully within the scope and purpose of my
gasohol composition containing the water of saturation
invention.
to a temperature of less than about ~30“ F. and, there
DESCRIPTION OF THE EMBODIMENTS
after, decanting the insoluble water of saturation.
30
8. The process of claim 1 wherein the gasoline com
EXAMPLE
position comprises an unblended, naphtha-type,
A gasohol composition is prepared comprising a
weak ethanol-water solution (about 10% by volume
straight-run gasoline composition.
alcohol) derived from a fermentation broth and from
gasohol comprises from about 85% to 93% by weight
gasoline and-7% to 15% by weight of combined alco
about up to 30%; for example, 15% to 25%, by volume
of amyl alcohol, based on the ethanol content of the
solution, as the alcohol-gasoline-miscible solution. The
solution is then employed in a liquid-liquid extraction
hol.
'
10. The process of claim 1 which includes the step of
extracting butanol or amyl alcohol from a butyl or
column and system (for example, employing sieve trays)
amyl-alcohol-containing fermentation broth employing
gasoline and, thereafter, employing the butyl or amyl
as the heavy phase and then is intimately mixed in one
or more stages in the column with an unleaded, blended,
alcohol-gasoline-extracted solution to extract the meth
anol or ethanol from the water-alcohol solution.
high-octane-type neptha gasoline'as the light phase. In
the liquid-liquid extraction process, the resultant mix
tures are separated into their respective phases, with
essentially ethanol-free water discarded and a gasohol
~
9. The process of claim 1 wherein the anhydrous
11. The substantially anhydrous gasohol produced by
the ‘process of claim 1.
45
12. A process for the direct preparation of substan
containing approximately 8% to 15% by volume of
tially anhydrous gasohol suitable for use in an internal
combined alcohols in the gasoline. The gasohol so pro
combustion engine from a fermentation broth contain
duced is further processed to reduce water of saturation
ing methanol or ethanol, which process comprises:
therein to a lower acceptable level, such as by reducing
(a) extracting in a liquid-liquid extraction process,
the temperature of the gasohol in a heat exchanger. The
from a methanol- or ethanol-containing fermenta
choice of the additive used, such as amyl alcohol or
tion broth, a methanol or ethanol from the broth
other additives, depends on the ability to shift the plait
employing as a solvent extractant an unblended,
point and the slope of the equilibrium tie lines to make
naphtha, straight-run gasoline composition in the
the most favorable separation, and the additive may
presence of from about 0.1% to 5% by weight of a
vary, depending on the type and composition of the 55
C3 to C6 alcohol to increase the solubility of the
gasoline used.
'
methanol or ethanol in the gasoline composition;
What I claim is:
(b) recovering a gasohol composition which com
1. A process for the direct preparation of gasohol
prises from about 85% to 93% gasoline and from
from a low-content alcohol-containing solution from a
fermentation broth, which process comprises:
60
(a) mixing in a liquid-liquid extraction process a fer
mentat'ion broth containing a methanol- or ethanol
water solution, the broth containing up to about
12% by volume of the methanol or ethanol, a gaso
line composition and a small amount of up to about 65
30%, based on the alcohol content of the water
alcohol solution, of a solvent for the methanol or
ethanol and miscible in the gasoline;
about 7% to 15% of combined alcohol and con
tains water of saturation;
(c) reducing the temperature of the extracted gasohol
composition to approximately - 10° F. or below to
render insoluble in such solution at least part of the
water of saturation present therein; and
(d) removing the water of saturation to provide a
substantially anhydrous gasohol.
13. The substantially anhydrous gasohol produced by
the process of claim 12.
5
4,251,231
6
(e) withdrawing from the extraction column a gaso
14. The process of claim 1 which includes admixing
the alcohol solvent with the alcohol-containing fermen
tation broth prior to mixing the fermentation broth with
hol composition which comprises the gasoline
composition, the solvent, the ethanol or methanol
of the fermentation broth and water of saturation;
(f) withdrawing from the extraction column an essen
tially methanol- or ethanolafree, aqueous, fermenta
the gasoline composition.
15. The process of claim 1 which includes mixing the
fermentation broth, the solvent and the gasoline compo
tion broth;
sition in a liquid-liquid extraction column, wherein the
(g) removing at least some of the water of saturation
fermentation broth is introduced as the heavy phase and
from the gasohol composition; and
the gasoline composition is introduced as the light 10 (h) recovering a substantially anhydrous gasohol.
phase, and wherein the solvent is in either phase.
17. The process of claim 16 wherein the solvent com
16. A process for the direct preparation of substan
prises a C3 to C6, volatile, low-molecular-weight alco
tially anhydrous gasohol from a fermentation broth
hol.
containing ethanol or methanol, which process com
18. The process of claim 17 wherein the anhydrous
prises:
15 gasohol comprises from about 8% to 15% by volume of
(a) introducing the aqueous fermentation broth, con
combined alcohol.
tainin g the ethanol or methanol as the heavy phase,
19. The process of claim 16 which includes reducing
in a liquid-liquid extraction column;
the temperature of the gasohol composition to — 10° F.
(b) introducing a gasoline composition, into which
or lower, to reduce the solubility of the water of satura
gasoline composition it is desired to introduce alco
hol to form a gasohol as the light phase in the liq
tion, and recanting from the low-temperature gasohol
composition the separated water of saturation.
20. The process of claim 16 wherein the solvent com
uid-liquid extraction column;
prises from about 0.1% to 5.0% by weight of the gaso
(c) introducing into the light- or heavy-phase compo
line composition.
,
sition a solvent for the ethanol or methanol, and
21. The process of claim 16 wherein the liquid-liquid
which solvent is also miscible in the gasoline com 25
extraction column contains a plurality of sieve plates.
position;
22. The anhydrous gasohol produced by the process
(d) admixing the broth, gasoline composition and
of claim 16.
solvent in a series of stages in the extraction col
i
umn;
30
35
45
50
55
60
65
*
*
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