PROCEDE DE PRODUCTION DE CARBURANTS A INDICE D'OCTANE ELEVE A PARTIR DE RESSOURCES RENOUVELABLES

PROCESS FOR PRODUCING HIGH-OCTANE FUELS FROM RENEWABLE RESOURCES

Abrégé anglais

A process for efficiently manufacturing a synthetic fuel from a renewable
resource whereby grains and fruits are first converted to alcohol and the
alcohol
is then partially converted to a high-octane, high-quality hydrocarbon fuel.
The
processed grains and fruits can be reused for other purposes.

Description

CA 02360981 2001-11-02
TEM File no. 240.1
TITLE: Process for Producing High-octane Fuels from Renewable Resources
FIELD OF THE INVENTION
The present invention relates to producing high-octane fuels in general,
and in particular to producing such fuels in a cost and energy efficient
manner
using renewable resources.
BACKGROUND
Gasoline usage worldwide is increasing while natural reserves are
decreasing and therefore it appears essential that gasoline or alternatives
fuels
must be manufactured from renewable resources in the coming future.
One such fuel, which can be made from a renewable resource, is Ethanol.
Specifically, organic vegetation, such as wheat, barley, corn, etc.,
containing
carbohydrates may be converted to sugar, which may then be converted to
alcohol when allowed to ferment. The overall process is somewhat energy
intensive, as the final product (namely alcohol) must be separated from water
utilizing a distillation process. The efficiencies of conversion plants vary
as some
require an energy input of up to 50,000 b.t.u.'s to produce one (1 ) gallon of
alcohol having an energy value of 85,000 b.t.u.'s.
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CA 02360981 2001-11-02
The small net gain in energy becomes a limiting factor with respect to the
economical feasibility of using a renewable resource for fuel. Further,
although
alcohol can be utilized as fuel in internal combustion engines, its inherent
energy
value of 85,000 b.t.u.'s per gallon is low compared to gasoline with a value
of
approximately 110,000 b.t.u.'s per gallon.
In view of the aforementioned problems, it is an object of the present
invention to provide a process for efficiently and economically producing a
high-
octane fuel from a renewable resource with an energy value comparative to
gasoline.
DESCRIPTION OF PROCESS
Drawing #1 illustrates a typical prior art ethanol production process where
grains (such as barley, wheat, corn, etc.) and water are introduced into tank
1.
The grains and water are initially mixed and cooked in tank 1 at a temperature
of
190 degrees F for approximately 12 hours. The resulting grain/water mixture is
then cooled to 140 degrees F and allowed to remain at this temperature for 12
hours. Yeast is then added and the mixture is cooled to 90 degrees F, and
allowed to ferment for approximately 60 hours. The mixture, or "mash", is then
pumped to a separation tank 2 where the solids exit from the bottom of the
tank
and the remaining liquid, which is approximately 12% alcohol at this point, is
pumped to the distillation tower 3. Water exits from the bottom of the
distillation
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CA 02360981 2001-11-02
tower and 190 proof alcohol exits from the top and is passed by a series of
cooling fins 4 to reduce the alcohol's temperature. Depending on design and
other conditions, the energy requirement to produce a gallon of alcohol ranges
generally between 19,000 to 50,000 b.t.u.'s.
Drawing #2 illustrates a process for producing synthetic fuel according to
a preferred embodiment of the present invention. The prior art ethanol
production process is modified in two manners. First, a heat exchanger 8 and a
hot water storage tank 7 are added to the production process as shown to re-
use
the heat generated in the ethanol production process. In doing so, the
theoretical
energy input requirements are reduced to an estimated 6000 b.t.u.'s as
compared to the earlier noted requirement of about 19,000 to 50,000 b.t.u.'s,
namely an anticipated decrease in energy input of approximately 68%.
Second, a catalytic converter 5 is provided downstream of the cooling fins
4 for de-oxygenating the alcohol to produce a useable hydrocarbon fuel in the
C5
- Coo range, and in so doing the fuel becomes immiscible with any remaining
water and may be separated in the separator 6.
In the catalytic reaction, conversion from alcohol to a hydrocarbon is a
function of pressure, temperature and space velocity, and normally would be
operated to achieve 100% conversion. In contrast, it is an object of the
process
of the present invention to provide operating conditions, with respect to
temperature, pressure, and space velocity, wherein only 85% conversion is
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CA 02360981 2001-11-02
accomplished. In doing so, a more commercially valuable, higher-octane fuel is
produced.
Accordingly, additives, whether lead or non-lead, should not be required
downstream to enhance octane ratings prior to sale or use of the fuel.
In addition to the benefits of producing a high-octane fuel by the present
process, the catalytic conversion is an exothermic process whereby heat is
generated. Hence, by including an additional heat exchanger in the present
process, the aforementioned heat may be cycled back to the primary alcohol
section of the process to further reduce energy requirements.
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