|
BioPetrol
|
| Biomass
for Bio-ethanol |
| Ethanol made from cellulosic biomass is called
bioethanol. A major challenge is developing biocatalysts capable
of fermenting lignocellulosic biomass for efficient industrial
application. In the coming years it is believed that cellulosic
biomass will be the largest source of bioethanol. The broad
category of biomass for the production of ethanol includes agricultural
crops & residues and wood. Biomass resources are abundant
and have multiple application potential. Among the various competing
processes, bioethanol from lignocellulosic biomass appears to
have near-term economic potential. The crops residues such as
rice straw, bagasse etc are not currently used to derive desired
economic and environmental benefits and thus they could be important
resource bases for bioethanol production. The table below indicates
potential of such biomass for ethanol production. |
|
Potential for ethanol from cellulosic
matter
|
| Feedstock |
Gallons ethanol/dry
ton
|
| Bagasse |
112
|
| Corn stover |
113
|
| Rice straw |
110
|
| Forest thinnings |
82
|
| Hardwood sawdust |
101
|
| Mixed paper |
116
|
|
| |
| Review
of Technologies for Manufacture of Bioeth |
| The degree of complexity and feasibility of biomass
conversion to ethanol depends on the nature of the feedstock.
The three largest components of the biomass sources are cellulose,
hemicellulose, and lignin ranges of which are presented in Table
2.13. Ranges of sugar content in hardwoods, softwoods, and agricultural
residues are provided in Table 2.14. Lignin remains as residual
material after the sugars in biomass have been fermented to
ethanol. Economic use of this byproduct is critical to the financial
feasibility of biomass-to-ethanol technology. |
| Typical levels of cellulose,
hemicellulose and lignin in biomass |
|
Component
|
Percent Dry
Weight
|
|
Cellulose
|
40-60%
|
|
Hemicellulose
|
20-40%
|
|
Lignin
|
10-25%
|
|
| |
| Sugar
and Ash Composition of Various Biomass Feedstocks (Weight Percent) |
|
Material
|
Sugars
|
Lignin
|
Ash
|
|
Hardwoods
|
57-78%
|
15-28%
|
0.3-1.0%
|
|
Softwoods
|
49-69%
|
24-27%
|
0.1-0.4%
|
|
Ag Residues
|
42-81%
|
11-29%
|
2-18%
|
|
| |
| DEVELOPMENTS
IN BIOETHANOL PRODUCTION TECHNOLOGIES |
| Process steps |
| There are four basic steps in converting biomass
to bioethanol: |
| 1. Producing biomass results in the fixing of
atmospheric carbon dioxide into organic carbon. |
| 2. Converting this biomass to a useable fermentation
feedstock (typically some form of sugar) can be achieved using
a variety of different process technologies. These processes
for fermentation feedstock production constitute the critical
differences among all of the bioethanol technology options.
|
| 3. Fermenting the biomass intermediates using
biocatalysts (microorganisms including yeast and bacteria) to
produce ethanol is probably the oldest form of biotechnology
developed by humankind. |
| 4. Processing the fermentation product yields
fuel-grade ethanol and byproducts that can be used to produce
other fuels, chemicals, heat and/or electricity. |
| Technologies |
| There are four technologies for bioethanol production
as given below. |
| The first three are based on producing sugars
from biomass and then fermenting the sugars to ethanol. The
fourth is a very different approach involving thermal processing
of biomass to gaseous hydrogen and carbon monoxide, followed
by fermentation to ethanol. |
| 1.Concentrated
Acid Hydrolysis |
| This process is based on concentrated acid decrystallization
of cellulose followed by dilute acid hydrolysis to sugars. Separation
of acid from sugars, acid recovery, and acid reconcentration
are critical unit operations. Fermentation converts sugars to
ethanol. |
| The concentrated sulfuric acid process has been
commercialized in the past, particularly in the former Soviet
Union and Japan. However, these processes were only successful
during times of national crisis, when economic competitiveness
of ethanol production could be ignored. They cannot be economical
because of the high volumes of acid required. Improvements in
acid sugar separation and recovery have opened the door for
commercial application. Two companies in the United States(Arkenol
and Masada) are currently working with DOE and NREL to commercialize
this technology |
| Arkenol holds a series of patents on the use of
concentrated acid to produce ethanol. They are currently working
with DOE to establish a commercial facility that will convert
rice straw to ethanol. Arkenol plans to take advantage of opportunities
for obtaining rice straw a cheap feedstock in the face of new
regulations that would restrict the current practice of open
field burning of rice straw. Arkenol's technology further improves
the economics of raw straw conversion by allowing for the recovery
and purification of silica present in the straw. NREL is working
with Arkenol to develop a recombinant Zymomonas Mobilis strain
for the project. The facility is located in Sacramento County.
|
| Masada Resource Group holds several patents related
to municipal solid waste (MSW)-to-ethanol conversion. DOE and
NREL have been working with Masada to support their MSW-to-ethanol
plant, which is located in Middletown, NY. The plant will process
the lignocellulosic fraction of municipal solid waste into ethanol
using technology based on concentrated sulfuric acid process.
The robustness of this process makes it well suited to complex
and highly variable feedstocks like municipal solid waste to
take advantage of relatively high tipping fees available in
the area for collection and disposal of municipal solid waste.
|
| 2.
Dilute Acid Hydrolysis |
| Hydrolysis occurs in two stages to maximize sugar
yields from the hemicellulose and cellulose fractions of biomass.
The first stage is operated under milder conditions to hydrolyze
hemicellulose, while the second stage is optimized to hydrolyze
the more resistant cellulose fraction. Liquid hydrolyzates are
recovered from each stage, neutralized, and fermented to ethanol. |
| There is quite a bit of industrial experience
with the dilute acid process. Germany, Japan, and Russia have
operated dilute acid hydrolysis percolation plants off and on
over the past 50 years. However, these percolation designs would
not survive in a competitive market situation. Today, companies
are beginning to look at commercial opportunities for this technology,
which combine recent improvements and niche opportunities to
solve environmental problems. |
| BC International (BCI) and the DOE have formed
a cost-shared partnership to develop a biomass-to-ethanol plant.
The facility will initially produce 20 million gallons per year
of ethanol. BCI has utilized an existing ethanol plant located
in Jennings, LA. Dilute acid hydrolysis will be used to recover
sugar from bagasse, the waste left over after sugar cane processing.
A proprietary, genetically engineered organism will ferment
the sugars from bagasse to ethanol. |
| Tembec and Georgia Pacific are operating sulfite
pulp mills in North America, which utilize a dilute acid hydrolysis
process to dissolve hemicellulose and lignin from wood, and
produce specialty cellulose pulp. The hexose sugars in the spent
sulfite liquor are fermented to ethanol. The lignin is either
burnt to generate process steam or converted to value-added
products such as dispersing agents, animal feed binders, concrete
additives, drilling mud additives, and soil stabilizer. |
| 3.Enzymatic
Hydrolysis |
| The first application of enzymes to wood hydrolysis
in an ethanol process was to simply replace the cellulose acid
hydrolysis step with a cellulase enzyme hydrolysis step. This
is called separate hydrolysis and fermentation. An important
process modification made for the enzymatic hydrolysis of biomass
was the introduction of simultaneous saccharification and fermentation
(SSF), which has recently been improved to include the co-fermentation
of multiple sugar substrates. In the SSF process, cellulase
and fermenting microbes are combined. As sugars are produced,
the fermentative organisms convert them to ethanol. Enzymatic
hydrolysis will be used in Iogen/Petro Canada's Ottawa, Canada
project and is being explored for BCI's Gridely project. The
current high cost of cellulase enzymes is the key barrier to
economical production of bioethanol from lignocellulosic material,
research is on to achieve a tenfold reduction in the cost of
these enzymes. |
| Cellulase
Enzyme Research |
| The goal is to reduce the cost of using cellulase
enzymes in the bioethanol process by employing cutting-edge
and efficient biochemical technologies. The current estimate
for cellulase ranges from 30 to 50 cents per gallon of ethanol
produced. The objective is to reduce cellulase cost to less
than 5 cents per gallon of ethanol. This requires a tenfold
increase in specific activity or production efficiency or some
combination thereof. Nearer-term goals include a threefold increase
in cellulase-specific activity (relative to the Trichoderma
reesei system) by FY 2005. This may be possible by genetic manipulation
of microbes. |
| Biomass
Gasification and Fermentation |
| Biomass can be converted to synthesis gas (consisting
primarily of carbon monoxide, carbon dioxide, and hydrogen)
via a high temperature gasification process. Anaerobic bacteria
are then used to convert the synthesis gas into ethanol. Bioresource
Engineering Inc. has developed synthesis gas fermentation technology
that can be used to produce ethanol from cellulosic wastes with
high yields and rates. The feasibility of the technology has
been demonstrated, and plans are under way to pilot the technology
as a first step toward commercialization. The conversion of
a waste stream, the disposal of which is costly, into a valuable
fuel adds both environmental and economic incentives. The yields
can be high because all of the raw material, except the ash
and metal, is converted to ethanol. BRI has developed bioreactor
systems for fermentation that results in retention times of
only a few minutes at atmospheric pressure and less than a minute
at elevated pressure. These retention times result in very economical
equipment costs. The biocatalyst is automatically regenerated
by slow growth of the bacteria in the reactor. |
| Development
of Microbes |
| Microorganisms that ferment sugars to ethanol
include yeasts and bacteria. Research has focused on expanding
the range and efficiency of the organisms used to convert sugar
to ethanol. Breakthroughs in fermentation technology in the
past decade lead to commercialization of biomass conversion
technology |
| For most of this century, researchers assumed
that many of the sugars contained in biomass were not fermentable
particularly those contained in hemicellulose. This meant that
as much as 25% of the sugars in biomass were out of bounds as
far as ethanol production was concerned. In the 1970s and 80s,
microbiologists discovered microbes that could ferment these
sugars, albeit slowly and inefficiently. With the advent of
new tools in the emerging field of biotechnology, researchers
at DOE labs and at universities acrossUSA, have succeeded in
producing several new strains of yeast and bacteria(E. coli,
Zymomonas, Saccharomyces) that exhibit varying degrees of ability
to ferment the full spectrum of available sugars to ethanol.
|
| Today's ethanol producers are turning their attention
to corn fiber-the shell of the kernel as a source of additional
sugars for ethanol production. But, corn fiber, like other forms
of biomass, contains sugars that are not fermentable by today's
industrial fermentation organisms. Research is on to tailor
new microbes that can ferment these specific sugars. |
| Raw
materials for making bioethanol |
| Ethanol producers in the United States produce
around 1.5 billion gallons of ethanol each year, mostly derived
from corn. As demand for ethanol increases, other biomass resources,
such as agricultural and forestry wastes, municipal solid wastes,
industrial wastes, and crops grown solely for energy purposes,
will be used to make ethanol. Research activities over the past
20 years have developed technology to convert these feedstocks
to ethanol |
| Fuel ethanol is currently produced from the easily
fermented sugars and starches in grain and food processing wastes.
Soon, new technologies will be economically viable for converting
plant fiber to ethanol. A portion of the agricultural and forestry
residues (corn stover ,stalks, leaves, branches) which are presently
burned or left in the field may therefore be harvested for biofuel
production. There will be many benefits by connecting the established
corn ethanol industry with the emerging technologies that produce
ethanol from agricultural wastes and other types of biomass. |
| Meeting
the Ethanol demand for blending: |
| The ethanol demand for blending can be calculated
from the plan projection of the future growth in gasoline use.
The tables below provide the figures for the tenth plan together
with the availability. |
| Ethanol
Demand And Supply For Blending In Gasoline |
|
Year
|
Gasoline
demand
MMT
|
Ethano
ldemand
Th KL
|
Molasses
production
MMT
|
Ethanol
production |
Utilisation
of ethanol |
|
Molasses
Th KL
|
Cane
Th KL
|
Total
Th KL
|
Potable
Th KL
|
Industry
Th KL
|
Balance
Th KL
|
| 2001-02 |
7.07 |
416.14 |
8.77 |
1775 |
0 |
1775 |
648 |
600 |
527 |
| 2006-07 |
10.07 |
592.72 |
11.36 |
2300 |
1485 |
3785 |
765 |
711 |
2309 |
| 2011-12 |
12.85 |
756.35 |
11.36 |
2300 |
1485 |
3785 |
887 |
844 |
2054 |
| 2016-17 |
16.4 |
965.30 |
11.36
|
2300 |
1485 |
3785 |
1028 |
1003 |
1754 |
Notes:
1. Area under cane cultivation is expected to increase from
4.36 mha in 2001-02 to 4.96 in 2006-07 which would add additional
cane production of around 50 MMT.
2. About 30% of cane goes for making gur and khandsari. If
there is no additional increase in khandsari demand, sugar
and molasses production would increase.
3. The present distiller capacity is for 2900 Th kL of ethanol
and looks to be sufficient for 5% blend till 12 th plan
4. A growth of 3% in potable use and a 3.5% in chemical and
other use has been taken
|
| As per the All India Distellers Association, the
present installed capacity of alcohol production in the country
is 2900 million liters. With the present availability of molasses
to the tune of 9 million tonnes the alcohol production is around
1800 million liters. Out of which around 600 million liters
is surplus after meeting the demand of industrial use (540 million
litres) and potable use, (650 million litres). This is capable
of providing a 5% blend to the gasoline. The present consumption
of gasoline is estimated at 8.5 million tonnes requiring 502
million litres for 5% blend. The industry expects that the present
capacity able to meet the blending requirement of the gasoline
till the end of the Tenth Plan with the terminal years gasoline
consumption at 11.6 million tonnes needing 682 million liters
of ethanol for blending where 823 million liters will be surplus
from the production of 2300 million liters of alcohol. Decision
has already been taken to make it compulsory for a 5% blend
of ethanol in gasoline. |
| Since there is a surplus production of sugar and
export not giving much value addition it will not be irrational
to convert sugar to alcohol or directly came to alcohol in much
more proportion than being carried now. By this a 10% blend
of ethanol with gasoline can be maintained for considerable
period. Apart from sugarcane, other agro-products including
grains can be used for fermentation. Taking the crop yield in
account, sugarcane is the best choice as it is the crop having
the highest efficiency of photosynthesis and provide a possibility
of 1200 gallons of 99% alcohol from a acre. Potato provides
the next highest yield of alcohol on unit area of land; 300
gallons per acre. |
| From the table it is clear that for meeting 5%
blending demand, the ethanol capacity in the country is sufficient.
For higher blend and till the demand stablises, the crop productivity,
or use of bio-mass into converting to alcohol would be much
more needed. The Government has taken the decision to make the
5% blending in gasoline as mandatory in phased manner. As stated
above, the industry can easily meet the requirement if the land
is not diverted from cane production. |
| Alcohol Production from
molasses and Use |
|
(in million litre)
| year |
Molasses
Prod.MMT |
Production
of Alcohol (mil. litre) |
Industrial
use(mil. litre) |
Potable
use (mil litre) |
Other
uses (mil. litre) |
Surplus
availability of alcohol (mil. litre) |
|
1998-99
|
7.00
|
1411.8
|
534.4
|
5840
|
55.2
|
238.2
|
|
1999-00
|
8.02
|
1654.0
|
518.9
|
622.7
|
576
|
455.8
|
|
2000-01
|
8.33
|
1685.9
|
529.3
|
635.1
|
588
|
462.7
|
|
2001-02
|
877
|
1775.2
|
5398
|
647.8
|
59.9
|
527.7
|
|
2002-03
|
9.23
|
1869.7
|
550.5
|
660.7
|
61.0
|
597.5
|
|
2003-04
|
9.73
|
1969.2
|
578.0
|
693.7
|
70.0
|
627.5
|
|
2004-05
|
10.24
|
2074.5
|
606.9
|
728.3
|
73.5
|
665.8
|
|
2005-06
|
10.79
|
2187.0
|
619.0
|
746.5
|
77.2
|
742.3
|
|
2006-07
|
11.36
|
2300.4
|
631.4
|
765.2
|
81.0
|
822.8
|
|
| Potential of ethanol
production from sugarcane |
| Year |
Area
under cane |
Cane
prod |
Cane
utilization |
Sugar
production |
Addl.
Alcohol prod. (in million litre) |
|
|
|
|
Sugar
|
Gur
& khand
|
Seed
& chew
|
Target
|
Revised
prod.
|
From
addl. molasses prod.
|
Addl.
cane available for alcohol prod.
|
|
2002-03
|
4.36
|
309.9
|
181
|
92.0
|
37
|
182
|
192
|
69
|
475
|
|
2003-04
|
4.53
|
321.6
|
188
|
95.6
|
38
|
192
|
202
|
99
|
795
|
|
2004-05
|
4.63
|
333.3
|
195
|
98.3
|
40
|
199
|
212
|
128
|
1000
|
|
2005-06
|
4.79
|
345.1
|
202
|
102.1
|
41
|
206
|
223
|
168
|
1222
|
|
2006-07
|
4.96
|
356.8
|
209
|
104.8
|
43
|
213
|
233
|
198
|
1485
|
|
| |
| Economics
of alcohol production: |
| From
sugarcane: |
| A tonne of sugarcane, on an average, would provide
110 kg of fermentable sugar in the juice. If all the sugar juice
is fermented directly, the ethanol yield will be 70 litres taking
a sugar loss of 2% in spent wash and specific gravity of ethanol
as 0.79. The present price of sugarcane as fixed by Centre under
the minimum statutory price stands at Rs. 695/- per tonne with
8.5% recovery . At higher recovery which is the case always,
the effective price comes to Rs. 900/- per tonne if State Governments
does not add further cost to it. For example, the UP state has
added the statutory price by Rs. 45/- per tonne on the Centre's
price of Rs. 695/- . Therefore the feed stock price itself comes
to Rs. 900/70 = Rs. 13/- per liter of ethanol. A minimum of
Rs. 2/- per litre would be the conversion cost i.e. salary and
wages of the operational staff. In other words, direct conversion
of sugar juice to ethanol will cost more than Rs. 20/- per liter,
if we add the capital related charges of investment, profit
to the manufacturer, energy cost of making anhydrous alcohol,
transport, marketing, blending etc. This may not be financially
viable with present ex-factory cost of gasoline. To make it
viable following options are available:- |
| i. Sugarcane prices are decontrolled and left
for the market to decide. This may result into cane prices lower
than Rs. 500/- per tonne. |
| ii. Combining with sugar production so that major
part of cane cost is off-loaded to sugar. This is the present
situation also where all the ethanol production from sugarcane
is coming through molasses, a by-product in sugar production.
A tonne of sugarcane produces 100 kg of sugar as well as 40
kg of molasses the latter will produce around 10 liters of ethanol.
Even if sugar is sold at Rs. 10/- per kg it will be sufficient
to pay all the cost of the sugarcane. |
| iiii. Use of by-products bagasse and spent wash
very efficiently. The spent wash which is produced in large
quantity (around 15 liter for 1 lire of ethanol produced) can
be subjected to anaerobic digestion which not only removes its
BOD and COD but will also provide valuable bio-gas (60% methane)
which can meet 2/3rd of energy cost of making anhydrous alcohol
through conventional route. Using absorption or membrane technology
of drying alcohol above 95% purity, the biogas generation would
be sufficient for all its energy demand (if short by any margin,
the same could be made from the bagasse based cogeneration facility).
The bagasse which is left after crushing can provide electricity
through efficient co-generation. As per an estimate, a cane
crushing mill with 455 tph crushing capacity can generate 44
MW of power. This comes to about 97 kWh/tonne of cane crushed.
At a Rs. 2/- kWh rate of power exported to grid the earning
will be far sufficient to meet the cane prices even after meeting
the capital rated charges of installing the power generation
facility. To realise the energy efficiency as sated above, the
followings would have to be set up having the magnitude of the
capital investments as indicated -
· Molecular sieve costing around Rs 2-2.5 crore for
30 kld plant.
· Anaerobic bio-gas production costing Rs 4-5 crore.
· Steam and power generation plant (co-generation)
costing around Rs 3 crore/MW.
|
| Fortunately, apart from a low pay back period
for return in investments, there are several sources of getting
finance for setting up the facilities above (to increase efficiency)-
· Assistance from Asian Development Bank, KfW, Germany,
JBIC, Japan
· Assistance from IREDA under renewable energy plan
· Carbon credit of nearly $10/te of carbon saved under
CDM of the Kyoto Protocol.
|
| From
other feedstocks: |
| The other major source can be corn, sugarbeet,
potatoes etc. Depending on the starch content's in the feedstock,
the yield of ethanol would vary. Taking corn, it can be at 2.75
tonne of grains per kilolitre of ethanol. The feedstock cost
at Rs. 7/- per kg itself would cost Rs. 20/- in one litre of
ethanol so produced. The sale of the residue, (i.e. dried distillers
grains and solubles which is produced in the quantity of 0.56
kg per litre of ethanol produced would fetch a maximum of Rs.
3.5 @ Rs. 6/- per kg of residue unless the latter is converted
to more value added products. Thus the feedstock price after
taking the credit of the DDGS sale would not be lower than Rs.
16.5 per litre. The spoiled grain available in large quantity
(2-5 lakhs tonnes per year from FCI) would certainly make a
very cheap alcohol. For others, it is the market price that
will determine the economics. Generally foodgrain price will
be dictated by its use for human consumption which, in turn,
will be subjected to prices across other grains and alternatives.
|
| R&D
work
|
| While a boundary can be drawn to limit R&D
activities in the area of ethanol production from agro-crops
or biomass in general, but for short term requirement , the
following areas of research & development should be stressed
mainly towards the compatibility of the use of blends in existing
engines:-
|
| Ethanol-gasoline
blend: |
| a. Performance of engine and corrosion of ethanol
gasoline blend at higher ethanol percentage above 10%. Because
of the low water tolerance of alcohol-gasoline blends, anhydrous
ethanol must be used & great care must be exercised to avoid
water contamination. For 25 % alcohol blend, less than 2% of
water will cause separation. Ethanol can also be used in modified
engines, specifically designed and manufactured to operate on
ethanol fuel, and will generally be more efficient than modified
gasoline engines. |
| b. Most conventional vehicles on the road today
can use E10 (a 10% ethanol- 90% gasoline blend also known as
gasohol) without any special modifications. However, auto manufacturers
are also producing vehicles that are specially modified to run
on a higher percentage of ethanol. Generally, the use of ethanol
blending reduces the harmful emissions like CO, CO2 & hydrocarbons.
However, additional studies are required to understand potential
emissions benefits for all engine models and driving cycles.
Effect on exhaust treatment devices using ethanol blending should
also be established. The main mechanical differences between
ethanol and gasoline vehicles lie in the engine calibration
and the fuel management system. Ethanol vehicles come with a
special computerized system that monitors the ethanol/gasoline
ratio of the fuel, optimizes performance, and adjusts emissions
control devices. Ethanol may also corrode certain materials
that are commonly used in automobile parts, such as rubber and
plastic. Components that come in contact with the fuel, such
as piston rings, engine block, and valve seals, must be made
of ethanol-compatible materials. |
| c. Suitable additive for ethanol gasoline blend
to be used in two stroke engines. The use of ethanol in specially
designed two-cycle engines has been demonstrated on a limited
basis. The problem of using ethanol in these engines is that
the ethanol does not blend well with lubricating oil. To get
around this problem, research is under way to find lubricating
oils that are not affected by ethanol engines. The study on
In-use vehicle must also be considered because they are having
totally different configuration compared to new generation vehicles. |
| d. Andehyde Emission: Aldehyde emissions from
ethanol blends are generally higher than those from gasoline.
Formaldehyde, the major constituent in aldehyde emissions, is
a suspected carcinogen. However, the catalytic converters used
vehicles reduce aldehyde emissions to near the level produced
when unblended gasoline is combusted. The Royal Society of Canada
has concluded that any increases are minute, and harmful effects
are remote . |
| Ethanol-diesel
blends:
|
| e. E-diesel cannot be safely handled like conventional
diesel but must be handled like gasoline. This may necessitate
some modifications to storage and handling equipment, as well
as vehicle fuel systems. Stability is much less of a concern
for micro-emulsions as these have proven stable for extended
periods. However, stability of e-diesel micro-emulsions under
a range of storage conditions will need to be demonstrated.
Emulsifiers are known to extend the stability of ethanol-diesel
blends to lower temperatures at ethanol blending levels as high
as 15% or even 20% in conventional diesel. Detailed data on
the efficacy of emulsifiers as a function of temperature and
fuel aromatic content do not appear to be publicly available
& most manufacturers have not optimized emulsifier. A large
body of test data acquired in close cooperation with the OEM's
will be necessary to address this issue.Development of better
emulsifier for ethanol diesel blend. |
| f. Lubricity of e-diesel: Lubricity is the ability
of the fuel to lubricate metal surfaces and is relevant to wear
in fuel pumps and other engine components that are lubricated
by the fuel. Severely hydrotreated, ultralow sulfur diesel fuels
as well as Fischer-Tropsch diesel fuels tend to have low lubricity.
This can be remedied through the use of a lubricity additive
or by blending with higher lubricity components. Ethanol is
not expected to impart increased lubricity to diesel fuel. However,
most emulsifier manufacturers claim that the emulsifier itself
can impart improved lubricity. This would seem to be substantiated
by data made public by PEC that shows premium lubricity properties
(i.e. HFRR of less than 300 micron and SLBOCLE of more than
5200 g [jht1]). Better quantification of the effect of e-diesel
on fuel lubricity for both conventional and ultra-low sulfur
fuels is needed. The inclusion of lubricity in an e-diesel standard
may be desirable.
|
| g. Other problem of e-diesel: Concerns are expressed
related to engine performance using e-diesel. These include
the idea that the solvency effect of ethanol might loosen deposits
in older vehicles causing breakdowns. Another concern is that
because of e-diesel's higher volatility, there may be a greater
incidence of pump and injector cavitation, leading to increased
wear and hot restart problems. The lower energy content may
require changes to governing strategy to prevent stalling under
certain conditions such as steep grades, high temperature, and
altitude. While some of these concerns may prove to be unfounded,
they will require investigation. |
| Ethanol
production from biomass:
|
| h. Development of more energy efficient and economical
process for fermenting cellulose materials into ethanol. In
the coming years it is believed that cellulosic biomass will
be the largest source of bioethanol. The broad category of biomass
for the production of ethanol includes agricultural crops &
residues and wood. Biomass resources are abundant and have multiple
application potential. Among the various competing processes,
bioethanol from lignocellulosic biomass appears to have near-term
economic potential. The crops residues such as rice straw, bagasse
etc are not currently used to derive desired economic and environmental
benefits and thus they could be important resource bases for
bioethanol. A major challenge is developing biocatalysts capable
of fermenting lignocellulosic biomass for efficient industrial
application. Some narration on the possibility would be in order
which would also highlight the need of research in the area. |
| Conclusion: |
| 1. Though it is technically feasible to design
and run automobiles on 100% ethanol, for the reason of availability
and compatibility with vehicles presently in use blending of
ethanol with motor spirit needs to make a very modest beginning. |
| 2. Five percent blending has already been introduced
in some states. According to the information availability about
production and demand of ethanol for all applications, production
of molasses and distillery capacity, 7% blend of ethanol in
gasoline is feasible provided facilities to dehydrate alcohol
are added to the required extent. The target should be to raise
the blending in stages to 10% by the end of the X Plan. |
| 3. Ethanol may be manufactured using molasses
as the raw material. If the industry finds it economically feasible,
it should be encouraged to produce alcohol also from sugarcane
juice directly in areas where sugarcane is surplus. |
| 4. Restrictions on movement of molasses and putting
up ethanol manufacturing plants may be removed. |
| 5. Imported ethanol should be subject to suitable
duties so that domestically produced ethanol is not costlier
than the imported one. |
| 6. Ethanol diesel blending requires emulsifier
and also poses certain storage and technical problems. Indian
Institute of Petroleum is working on the subject. Ethanol diesel
blending should await the solution of the problems. |
| 7. Buyback arrangement with oil companies for
the uptake of anhydrous alcohol should be made. |
| 8. To reduce cost of production of ethanol, the
following measures may be considered:
A) Provision of incentives for new economic sized distilleries
incorporating state of art technology such as, molecular sieve
technology for making anhydrous alcohol.
B)Integration of distillery with sugar plant to have multiple
choice of making sugar, or direct sugarcane to ethanol.
|
9. The cost of ethanol produced using other raw
materials such as grains, potato, sugar beet and straw is estimated
to be more than the price of motor spirit and may need subsidy.
Economics of ethanol production from other feedstocks as sugar
beet, corn, potatoes, etc should be studied. It may be left
to the industry to use these raw materials for producing ethanol
as and when if it finds them economical.
|
| 10. R&D may be supported to reduce the cost
of ethanol production from different feed stocks.
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