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EcoMol Molecular Sieve Dehydration Plants
As the demand for fuel ethanol
grows, technology for production of fuel ethanol becomes critical.
Some of the key considerations while selecting the right technology
would be:
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How futuristic is
the technology so that it will remain current for
a long time and you will not be required to upgrade it constantly…
How does it build upon your current facilities
so that your investment in fuel ethanol plant is minimal…
Does it take care of your energy bill…
Can the technology handle a wide spectrum of raw materials…
Is the technology robust… Is it truly a clean technology
, with no presence of entrainers like cyclohexane…
The EcoMol Molecular Sieve Plants offers you
comfort on all the above factors.
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The EcoMol Pressure Swing
Absorption technology offers the following advantages:
There are two
modules available for recovering the alcohol in the regeneration
stream
Conventionally, azeotropic distillation
has been employed in production of Fuel-Ethanol. In azeotropic distillation,
dehydration is carried out in presence of entrainer like benzene
or cyclohexane. Although benzene has been banned in several countries
for its carcinogenic effect, cyclohexane is still being employed.
The distillation method is very energy intensive. A large number
of plants in Brazil still run on this technology.
To bring down energy consumption and to ensure high level of dryness
in final ethanol product, Molecular Sieve (MolSieve) has proved
to be ideal. Molecular Sieve is a synthetic adsorbent. It was introduced
more than a decade ago to dehydrate ethanol. Earlier systems operated
in liquid phase and used thermal swing regeneration process, which
did not make them very energy efficient. Further development on
the adsorbent saw introduction of vapor phase operation with pressure
swing regeneration system. This proved to be highly energy-efficient.
The vapor phase pressure swing regeneration system employs Molecular
Sieve beds which act as adsorbent. These beds are made of zeolite
with an effective pore size opening of about 3 Angstrom.
In order to understand the process of dehydration of ethanol, consider
a column packed with freshly activated Molecular Sieve. As rectified
spirit (hydrated ethanol) vapor first enters the bed, water is diffused
and adsorbed within the pores of the adsorbent structure in a thin
layer. As more alcohol enters the column, it passes through this
layer to slightly lower level where another incremental amount of
water is adsorbed. This continues until a point is reached where
all possible water adsorption from this slug of alcohol is accomplished.
Transfer of water from the vapor of rectified spirit to the Molecular
Sieve occurs through a zone where water (adsorbate) content is reduced
from its inlet to its outlet concentration. This finite length of
bed, where the adsorbate transfer occurs, is known as the mass transfer
zone. Two beds are provided in order to make the process continuous.
Whilst the active bed is under pressure carrying our dehydration,
the regeneration bed is under vacuum. The shift of operation (swing)
from one bed to another is controlled with help of control valves
and automation.
What is fuel ethanol?
Fuel ethanol or anhydrous alcohol is produced
by dehydration of rectified spirit or extra neutral alcohol. Ethanol
used as part of the fuel, by blending with petrol, for a motor vehicle
is called fuel-ethanol.
How it is mixed in Petrol/Gasoline?
Ethanol could be blended in various proportions
in petrol. Ethanol is usually added 5 to 10% by volume of petrol
for such application. In Brazil, ethanol is added 24% by volume
in gasoline (petrol).
How does it help in reducing pollution?
Use of ethanol in place of tetraethyl lead or
MTBE which acts as anti-knocking agents will prevent dangerous and
poisonous emissions containing lead or MTBE from petrol.
Will I have to change the engine of
my Car?
Many states in the US have been using 10% ethanol
blend in gasoline (petrol) for use in their cars. Brazil has been
using up to 24 % ethanol in petrol. Engines of cars do not need
any change to use petrol with up to 24 % ethanol in it.
Will the engine of my vehicle get
damaged?
Ethanol has, apart from carbon and hydrogen,
oxygen in it. This oxygen acts as oxygenating agent during combustion
in the IC engine of petrol cars, two-wheelers and three wheelers
thus preventing formation of carbon monoxide. Gasoline with ethanol
as anti-knocking agent will not cause any damage to the engine.
Can it be used in Two-wheelers/Three-wheelers
without any change in vehicles?
Yes! Of course you can use gasoline in Two-Wheelers/Three-Wheelers
as a normal fuel without changing the engine or any other things.
Can it be added in Diesel?
Ethanol is also added to diesel. Usually, 3%
by volume is added. Tests have been conducted satisfactorily with
up to 10% by volume addition.
Which are the other countries, which
have promoted fuel ethanol?
Many states in the US have been using 10% ethanol
blend in gasoline (petrol) for use in their cars. Brazil has been
using up to 24 % ethanol in petrol. Engines of cars do not need
any change to use petrol with up to 24 % ethanol in it.
Fuel ethanol programs have now been initiated in countries like
Australia, Nepal, Columbia, Poland, Sweden etc.
What is the experience of countries
who have promoted fuel ethanol?
Reduced oil imports, improved trade balance,
reduced reliance on imported oil, increased ethanol production,
more cane price to farmers, direct and indirect job opportunities,
saving fossil fuels are some of the experiences.
what is E85? How do I
know if my vehicle can use it?
E85 is fuel comprised of 85% ethanol / 15%
unleaded gasoline for use in Flexible Fuel Vehicles(FFVs). These
vehicles are truly flexible in that their owners have a choice
whether to use E85, any blend of ethanol upto 85% level, or straight
unleaded gasoline. On some models this comes as an option, and
on some if is a standard feature.
Can my vehicle run on
E85 even if it is not an FFV?
if your vehicle is not an FFV, use of any higher ethanol percentage than 10% is not covered by warranty.
What is ethanol made from?
While 1/3rd of world ethanol production is from corn, the rest is produced from suger based raw material like sugarcane juice/molasses or beet juice/molasses. There
are other grains used in the production of ethanol which is rice, wheat, rye, dorghum or tubers like cassava / tapioca.
What is cellulosic ethanol?
Cellulosic biomass, holds tremendous promise
as a feedstock for ethanol production due to its widespread availability
and potential for high fuel yields.
Examples of sources for celluosic ethanol
include corn stover (the stalks and husks left over after harvest),
wheat and barley straw, sugarcane or rice bagasse, sawdust, paper
pulp, small diameter trees and dedicated energy crops such as
switch grass and other fast growing grasses. Study is still going
in making cellulosic ethanol more viable. Praj is engaged in preliminary
study leading to lab scale R & D.
How cellulosic ethanol made?
As with producing ethanol from grain, processing
cellulosic sources extracts the fermentable sugars from the feedstock
for distillation into alcohol. Unlike in grain, the sugars in
cellulose are locked in complex carbohydrates called polysaccharides,
or long chains of simple sugars. Separating these complex structures
into fermentable sugars is essential to the efficient and economical
production of cellulosic ethanol.
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