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A Comparison of Gasoline and
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Total Fossil Fuel Jonsumption

presented by

Mahmood Ahmad Baluch

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of the requirements for

Master's degree in Mechanical Engineering

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Date June 27, 1995

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A COMPARISON OF GASOLINE AND
ETHANOL FUELED ENGINES IN TERMS OF
TOTAL FOSSIL FUEL CONSUMPTION

BY

Mahmood Ahmad Baluch

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Mechanical engineering

1995

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ABSTRACT

A COMPARISON OF GASOLINE AND
ETHANOL FUELED ENGINES IN TERMS OF
TOTAL FOSSIL FUEL CONSUMPTION

BY

Mahmood Ahmad Baluch

Crude oil reserves are being depleted everyday and the
drilling of new oil wells is becoming uneconomical.
Alternative fuels are being investigated to ensure
availability of fuels and to reduce the dependence on the
few oil exporting countries.

An investigation into consumption of fossil fuel in

the production of gasoline and ethanol has been carried out.

It covers a comparative study about the consumption of
these fuels in vehicles, on the basis of energy only. The
study also includes other related aspects such as the effect
on emission, modifications required on the engine to operate
on ethanol blended gasoline, and sensitivity analysis of the
production of fermentation ethanol. -

The results show that far less fossil fuels are
consumed in the production of fermentation ethanol from corn
than gasoline. However, more ethanol blended gasoline is

consumed to cover same distance than gasoline and this

trend increases as the quantity of ethanol is increased in

the blend.

to my parents and family for their

devotion and patience

iv

ACKNOWLEDGMENT

I am grateful for the opportunity to work with
Professor C.W.Somerton; for his guidance and assistance
in this work.

My parents are appreciated for their endless
support, without which this point could have never been
achieved. I am eternally grateful for the patience,

understanding, and support of my wife and kids.

TABLE OF CONTENTS

LIST OF TABLES ........................................ viii
LIST OF FIGURES ........................................ ix
NOMENCLATURE ............................................ x
Chapter
1 INTRODUCTION ......................................... 1
1.0 Literature Review .............................. 6

2 RESULTS AND DISCUSSION
2.0 Need to change Over from Gasoline to Ethanol
2.0.1 To Reduce Undesirable Emissions ......... 8

2.0.2 To Supplement Oil Reserves/Ensure

Economic Availability of Fuel ........... 9

2.0.3 To Improve Yield and Octane Rating ...... 10
2.0.4 To Reduce Unemployment .................. 11

2.1 Comparison of Fuel Consumption ................. 11
2.1.1 In terms of miles per gallon ............ 12
2.1.2 In terms of miles per Btu ............... 13

2.2 Effects on Emission ............................ 18
2.3 Sensitivity Analysis ........................... 20

vi

2.3.1 Feedstock Cost .......................... 22
2.3.2 Capital Cost ............................ 23
2.3.3 Operating Cost .......................... 24

2.4 Modifications Required on Engines and Related
Systems ........................................ 26

2.5 Comparison of Fossil Fuel Energy Consumed in

Production of Gasoline and Ethanol ............. 30
2.5.1 Gasoline ................................ 30
2.5.2 Ethanol ................................. 31

2.5.3 Calculations

2.5.3.1xFertilizer Based ................ 31
2.5.3.2 Gasoline Based .................. 32
3.0 Conclusion ..................................... 33

vii

TABLE 1.0:

TABLE 2.0:

TABLE 3.0:

LIST OF TABLES

Percentage of ethanol and corresponding miles
per gallon

Percentage of ethanol and corresponding miles
per Btu

Advantages and disadvantages

viii

14

16

35

LIST OF FIGURES

FIGURE 1.0: Percentage of ethanol vs. miles per gallon 15

FIGURE 2.0: Percentage of ethanol vs. miles per Btu 17

ix

BATF
bbl
Btu

CAFE

etc.
Eth
°F
Fert
gal
gas
HC

1bm.

MON
N02

RON

NOMENCLATURE

Bureau of Alcohol, Tobacco and Firearms

Barrel

British Thermal Unit

Corporate Average Fuel Economy

Aldehydes

Compressed Natural Gas

Carbon Mono Oxide

Environmental Protection Agency
Etceteras

Ethanol

Degree Fahrenheit

Fertilizer

Gallon

Gasoline

Hydrocarbons

Pound Mass

Liquid Natural Gas

Cubic Meter

Motor Octane Number

Nitrogen Per Oxide

Research Octane Number

SO; Sulfur Dioxide

UBF Unburned Fuel

US United States

USDA united States Department of Agriculture
5 Dollar

% Percent

xi

CHAPTER 1

INTRODUCTION

Fossil fuels, particularly crude oil is the primary
fuel used for transportation all over the world. Rapidly
depleting reserves of crude oil and increasing pollution
problem have been a source of concern. Most countries have
suffered the energy shortage problem in 19703, when supply
of crude oil was stopped for one reason or the other by the
few oil exporting countries.

The United. States imports about 50 percent of its
crude oil requirement, which creates a cash outflow of $10
million per hour [1]. The U.S. can no longer depend on oil
reserves outside its control to meet its energy' needs,
specially during critical moments. At the present rate of
use, U.S. petroleum reserves represent about a 16 years of
supply [4]. Precedence of the 1970's energy crisis, need to
supplement and prolong life of depleting oil reserves, and
desire to control pollution demand a search for an
alternative fuel to gasoline. Alternative fuels include

electricity, hydrogen, liquid and/or compressed natural gas,

2
alcohols, their blends with unleaded gasoline, and synthetic
fuel from oil shales and tar sands.

Alcohol fuels have been investigated as alternative to
gasoline for many decades. Thus, a great deal is already
known. about their" compatibility' with. internal combustion
engines. In the past the high cost of alcohol fuels,
compared to gasoline, was a deterrent to their use. However,
environmental and long-term supply issues have recently
renewed interest in their use as an alternative fuel.

The alcohols, of primary interest as alternative to
gasoline are ethanol and methanol since these can be
readily produced in large quantities [15]. Alcohols have an
advantage over gasoline since these can be produced
(although at high cost presently) by using a very small
quantity of irreplaceable petroleum reserves which will be
exhausted inevitably. As long as the sun shines, and plants
grow, alcohols will be unique because they’ possess the
attribute of perennial renewal. However one must remember
that there is a considerable consumption of fossil fuel in
agricultural production.

In the U.S., interest in ethanol as a motor fuel was
stimulated, during 19703, by the shortage of gasoline during
the energy crisis. Since ethanol can. be fermented from

grain, corn, and other biomass, its production was

3

encouraged to reduce the U.S. dependence upon imported fuel
[4]. The raw material for commercial scale ethanol
production is readily available in various forms. The major
feed stocks are: corn, wheat, sorghum, barley,
potatoes,sugar beets, sweet sorghum, sugar cane, and fodder
beets.Therefore, the past several years have seen an
increased emphasis on domestic alternatives, and pressure to
produce lOW’ cost fermentation ethanol from. Ibiomass
resources.

The use of ethanol as a fuel, supplement the imported
crude oil as a domestic renewable resource with the added
benefit of superior anti knock properties. Use of ethanol,
either as substitute of gasoline or a blend with gasoline,
not only cuts down the amount of crude oil imported but also
reduces the regulated emission products (HC, CO, and NOX) in
exhaust gases [16].

Ethanol, either pure or blended with gasoline, is
being used in over 40 countries in different proportions.
Any country's use of alternative fuels depends on the
severity of its need to reduce imports to balance payments,
cut down its dependence on other countries, and the
availability of indigenous natural resources. Brazil, Cuba,
the Philippines, having large supply of sugar cane, are busy

in research in this field. Since 1975, Brazil has had a huge

4

program in operation to cause a national change from the use
of petroleum to alcohol fuels. Brazil is now using 20
percent alcohol blends regularly and large fleets of
government or industry owned cars run on 100 percent
alcohol.

Gasohol, a blend of 10 percent anhydrous fermentation
ethanol and 90 percent unleaded gasoline, was marketed in
mid 19703 in time U.S. In 1982, the U.S.E.P.Aa mandated
reduction in the lead content of gasoline that required
refiners to seek other agents to increase the octane number
of finished gasoline. Ethanol, is an. effective "Octane
enhancer", when blended with gasoline. The use of ethanol as
fuel for vehicles in the U.S. has grown from insignificance
in 1977 to nearly 900 million gallons in 1990 [14].

This work includes a comparative study of consumption
of gasoline and ethanol fuels on the basis of their energies
only. It covers other aspects such as effect on emission,
modifications required on engines and related systems,
sensitivity analysis of cost of production of ethanol. It
also includes an investigation into the consumption of fossil

fuel energy in their production. The study is based on

production of ethanol from corn only. All the statistical
data used in this work is based on 1990's production of corn

and fossil fuel in Michigan or nearby states.

1.0 Literature Review

Several studies have been carried out to evaluate
alcohols as an alternative fuel from. different technical
points of view such as, their' production, fuel economy,
emission. control, drive ability, engine compatibility’ and
modifications, impact on food etc.

The fermentation ethanol industry has emerged through a
combination of government incentives and new technologies,
which enabled large scale production of ethanol from domestic
resources, particularfy corn. The falling cost of production
of ethanol along with growing consumer acceptance of ethanol
blended gasoline are responsible for the jump in the ethanol
production. Hohmann [14] , examines the likelihood of
obtaining further reductions in the cost of ethanol by the
introduction of new technologies. He expects that cost
reductions to the tune of 5-7 cents per gallon are likely by
1996, which can further be increased to 9-15 cents per gallon
by the year 2001.

Bata [16], used a 1978 Ford, 2.3 liter, in line four
cylinder with an overhead cam shaft, 9:1 compression ratio,
cogged belt drive and two barrel carburetor, engine mounted

on a super flow SF—800 dynamometer to investigate the effects

7
of using anhydrous ethanol blended in unleaded gasoline fuel
on exhaust emissions (CO, HC, and CHO). In this work, he
found that the product CO decreased as the percent of alcohol
in the blend was increased. The effect of alcohol on HC was
insignificant whereas CHO emissions were markedly increased,
however the UBF was slightly increased.

Tyner [19], in his paper discusses the moral issues in
using corn for the production of ethanol. He concludes that
use of feed grains for alcohol production may involve
tradeoffs in the price and quality of meat, poultry and dairy
products. However, it would not directly affect the
availability of food at lower to moderate levels of alcohol
production but it may happen at higher levels of alcohol
production.

Thring [15], examined alternative fuels for spark
ignition engines such as, synthetic fuels, alcohols, methane
gas, LNG, CNG, hydrogen gas. He studied the use of alcohol as
motor spirit under two heads, i.e., effects on engines, and
its handling problems. He concludes that alcohols, primarily
methanol and ethanol, offer possible alternatives but suffer
from certain disadvantages (e.g., low calorific value) that
makes these two less attractive. However, these will be used

in certain areas where suitable feed stocks are available.

CHAPTER 2

RESULTS AND DISCUSSION

2.0 Need to change over from gasoline to ethanol

Presently the cost of ethanol is not competitive with
gasoline without Federal and State government subsidies, but
with the development of technology and other innovations it
is expected to become so in near future. However, there are
certain other factors which over ride cost factor and demand
use of ethanol as motor fuel.
2.0.1 To reduce undesirable emissions

The quality of air we breathe has been a public concern
for several decades. Emission of 802, HCS, CO, lead, and N02
(the so <ca11ed "criteria pollutants") have commanded our
attention for nearly thirty years. Chloroflourocarbons, green
house gases “3%: and methane), and toxic air pollutants
gained our attention rapidly jJitflue last decade because of
their suspected impact on the earth's atmosphere and human

health.

9

Motor vehicles emit green house gases and toxic air
pollutants. Petroleum fuels consumed by motor vehicles in the
U.S. contributed 31.8 percent of the total C02 emission in
1986. C02, a green house gas, is contributing to what some
scientists believe may be a gradual warming up of earth's
climate. Benzene, a known human carcinogen, is emitted during
refueling of gasoline powered motor vehicles. Less is known
about the impact of emissions from vehicles using alternative
fuels on potential global warming.

The motor vehicle's pollution problem can not be solved
by stringent emission control technologies and C.A.F.E.
requirements only. However an alternative fuel or mixing some
additive in gasoline may solve this problem. The present
interest in ethanol as motor fuel, results from the hope that

it may reduce exhaust emissions.
2.0.2 To supplement oil reserves/ensure economic availability
of fuel

The U.S. imports about 50 percent of its need of crude
oil which creates a cash outflow of $ 10 million per hour. At
the present rate of production and use, petroleum reserves
within the U.S. control represent about 16 years of supply.
Precedence of the 1970's energy crisis, and expected increase
in the price of imported oil, demands search and use of

alternative fuels.

10

It is expected that by the year 2000, there will be
dire need to use fuels obtained from sources other than oil
wells mainly due to the uneconomical availability of
conventional crude oil. These will be obtained either from
one source or a combination of sources depending on the
demand and availability of the raw materials. In view of the
depleting oil reserves and the desire for energy
independence, some compromise on the properties of these
fuels may be inevitable. This may affect fuel economy, drive
ability, vehicle performance, fuel system and engine
durability and fuel integrity etc. These fuels may either
substitute or supplement the conventional fuel. The
fermentation ethanol obtained from corn is one of the various
alternate fuels being researched.
2.0.3 To improve yield and octane rating

Because of the adverse effects of lead compounds, used
as octane enhancer, the conversion to unleaded gasoline was
mandated some years ago. The change in refinery operations,
required to produce fuel of a given octane rating with out
lead additives, reduced the quantity of fuel obtained from
crude oil. The octane boosting process requires additional

energy in the refining process.

11
Addition. of ethanol to gasoline not only" gives the
required octane boost but it saves the supplementary energy
expenditure in the refining process and also improves ' the
yield . Therefore, the requirement of crude oil is reduced by
the amount of ethanol used in the blend and the crude oil
saved by using ethanol as octane enhancer.

2.0.4 To reduce unemployment

Recent estimates by the CLS.D.A suggest that about 78
million acres of land, presently not being used for crops,
has a high potential for cropland development. The
development of such a vast area into cropland could translate
to a 33% increase of corn production which will be a
significant increase in the ethanol feedstock resources. It
will also solve the problem of unemployment.

2.1 Comparison of fuel consumption

The effect on fuel economy by blending ethanol with
unleaded gasoline is somewhat clouded by the fact that the
effects are different depending on the method used to measure
fuel economy. Consumption of a fuel in the engine depends on
many factors such as heating value, stoichiometric air to
fuel ratio, specific gravity, vapor pressure, viscosity,
specific heat etc.

However, in this work the comparison, between pure

gasoline and ethanol blended gasoline, is done on the basis

12
of their lower’ heating ‘values only. Fuel consumption of
gasoline is taken as 27.5 miles per gallon, being C.A.F.E
standard for 1990 model cars. Two comparisons are being done
here; one is for miles per gallon and the other is for miles
per Btu.

2.1.1 In terms of miles per gallon

Formula used to calculate the consumption of a vehicle
fueled with ethanol blended gasoline in different ratios is
given below. Results so obtained are shown in Table 2.1 and
Figure 2.1. Since ethanol has much lower heating value than
gasoline, the heating.value of their blend in any proportion
will always be lower than the gasoline alone. This is the

reason why fuel consumption of the ethanol-gasoline blend is

more than gasoline.

Y = [(I-X) figm+(x)l;eth ]
27.5 13...

 

Y = mpg of x% of ethanol in gasoline

A

hga, = the lower heating value of gasoline (116,48SBtu/ gal)

he». = the lower heating value of ethanol (76,1 SZBtu / gal)

13

2.1.2 In terms of miles per btu

Formula used for calculating " miles per Btu" for a
vehicle is given below. Data used in this calculation is
taken from Table 2.1 for different blends of ethanol in
gasoline. Results so obtained are shown in Table 2.2 and
Figure 2.2.

These results indicate that with the increase in the
percentage of ethanol in the blend, better milage per btu is
obtained. It must be appreciated that an assumed value of
processing energy for ethanol has been used in the
calculations. It is hoped that a better picture may emerge if

exact figures for this assumption are available.

 

 

 

Miles = Miles x galofeth x%ofeth + Miles x galofgas

x%ofgas
Btu gal Btu gal Btu

l4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

S.No % of Ethanol Mpg
1. 0 27.5000
2. 10 26.5478
3. 20 25.5956
4. 30 24.6434
5. 40 23.6912
6. l 50 22.7390
7. 60 21.7868
8. 70 20.8346
9. 80 19.8824
10. 90 18.9303
11 100 17.9781

Table 1 Showing percent of ethanol in the blend and

corresponding consumption in mpg

 

CONSUMPTION - MILES PER GALLON

 

 

 

MILES PER GALLON
a:

 

 

 

“—1
Series1 l
10 -
5 4-
o n A
O O O O O O D O O O O
u- N F) V In (D l\ w G) e
7. OF ETHANOL

Fig.2.1. Graph showing fuel consumption in terms of miles / gallon

4
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l

i

16

 

 

 

 

 

 

 

 

 

 

 

 

S.No. % of Ethanol Miles per Btu
1. 0 0.00010
2. 10 0.00032
3. 20 0.00052
4. 30 0.00071
5. 40. 0.00088
6. 50 0.00104
7. 60 0.00118
8. 70 0.00130
9. 80 0.00141
10. 90 0.00150
11 100 0.00157

 

 

 

 

 

Table 2 : Showing percent of ethanol in the blend and

corresponding consumption in miles per Btu

 

CONSUMPTION-MILES PER BTU

0.0016

 

0.0014 -
0.0012 ,_
0.001 - ‘
0.0000 . :sgr fl
0.0006 .. ,

MILES PER BTU

0.0004 -

0.0002 —

 

 

 

 

PNMVID‘DNC
‘-

'/0 OF ETHANOL

 

Fig 2.2. Graph showing fuel consumption in terms of miles/Btu

18

2.2 Effects on emission

Approximately 128 billion gallons of gasoline and
diesel fuel were burnt in 1988 by vehicles only. The number
of vehicles on the road is increasing every day and so is
the amount of fuel being burnt. These vehicles emit a large
share of pollutants in the air we breathe, i.e. 66% of
CIh,SO% of N02, and 37% of HCS. Vehicle exhaust and
evaporative emission controls, required by the U.S.E.P.A,
have significantly reduced the pollutants emitted by
individual motor vehicles in the last two decades. These
pollution control gains have been achieved by improving
combustion and fuel system controls and by adding catalytic
convertors to the exhaust system. However, the continual
increase in the number of vehicles on the roadways and the
increasing number of miles driven offset a large portion of
these improvements in pollution control.

There appears to be widespread agreement that, compared
to gasoline, ethanol containing fuels have the positive
feature of generating less CO when combusted. This is
primarily attributed to the "leaning effect" of the ethanol.
On the other hand, there is a near consensus that such fuels
have the negative feature of causing higher CHO emissions.
For HC and N02 emissions the picture is somewhat ambiguous,

with some researchers reporting lower HC and/or N02

19
emissions for ethanol containing fuels, while others report
higher emission levels of these species. In most cases the
percentage differences in N02 and true HC release for
alcohol fuels and gasoline were comparatively modest.

Much of the apparent inconsistency in N02 and HC
emissions comparison, for' alcohol ‘versus gasoline, among
various investigations may be attributed to differences in
test procedures, emission control equipment, and engine
operating parameters, particularly the equivalence ratio.

Ethanol has a greater cooling effect on the intake
charge than gasoline, and this effect persist throughout the
engine cycle. Since the formation of N02 varies with the
time temperature histories of each portion of the charge,
this reduction in the temperature causes a reduction in
exhaust emission of N02. Furthermore, since ethanol fueled
engines can be made to run leaner, a further reduction in
charge temperatures and N02 emissions could be achieved.
These reductions in Nozlare some what offset by any increase
in compression ratio, but nevertheless, N02 emissions are
about half the values obtained with gasoline.

Exhaust emissions of unburned. HC are also reduced,
partly because of the leaner operation possible with
ethanol. The ability to operate leaner produces a reduction

in CO. Ethanol has high octane number, and the octane number

20
improvement resulting from the addition of lead compounds is
poor. Therefore, there is no point in adding lead to them,
and hence there is no exhaust emission of lead. There is
usually only a negligible quantity of sulfur in ethanol, so
there is no sulfurous emission with ethanol.

2.3 Sensitivity analysis

Presently ethanol is not competitive with gasoline'
without substantial government subsidies. However, the
ethanol fuel industry is poised to adopt a wide range of
technologies which would reduce costs at every stage of the
production process.

The cost of producing ethanol will also be greatly
reduced by the technological advances other than the
innovations in the plant. It is expected that the longer
term technologies would save approximately 9-15 cents per
gallon over present cost. Energy and feedstock savings will
result from technology which can convert some of the non
starch portions of corn to ethanol. Development of certain
micro organisms which speed up the process will also
contribute to long term savings. Development of markets for
co—products of ethanol production will create additional
savings.

The science and art of production of fuel grade ethanol

by fermentation are well established. Although yields and

21
energy requirements appear to be close to the maximum and
minimum values, respectively, but some improvements are
still possible. These arise out of research in areas such as
continuous fermentation, development of yeast strains that
are more temperature tolerant, alcohol separation and
dehydration methods than distillation.

Various government agencies also influence the
production of fermentation ethanol which may affect the cost
of ethanol. The U.S.D.A. may influence feedstock
availability and prices. The B.A.T.F. requires permits for
the production. The E.P.A. impacts on stillage disposal.

By way of projection, the price of oil and gasoline
should continue to increase at a rate more than the general
inflation rate, where as biomass based fermentation ethanol
should increase only at the general inflation rate. Thus,
one can .reasonably' assume that the ethanol ‘price should
become economically competitive with out government subsidy
incentives with the passage of time.

Technological innovations in converting corn to ethanol
along with the technical developments will possibly lower
all the three components of production costs: feedstock,
capital, and operating costs. In near term, the adoption of

innovations in new facilities will result in lower equipment

22
and ingredient costs, and slight increase in ethanol yield

over current plants.

2.3.1 Feedstock cost

Feedstock cost is a measure of the net cost of the
grain from which ethanol is produced. The net cost of corn
is the difference between the cost of corn and the total
revenues received from the sale of co—products. Over a
period of 10 years, the net corn cost has been volatile,
ranging from 10 to 67 cents per gallon of ethanol. This
volatility is mainly due to the large swings in the price of
corn, but changes in the co-product prices have also
contributed. Average net corn cost (1981—1991) have been 44
cents per gallon of ethanol in a wet mill and 53 cents per
gallon in a dry mill plant. Lower net feedstock costs can be
achieved by either lowering the cost of corn, or raising the
price of co-products, or both of them simultaneously.

Farm technologies which raise corn yields or reduce
input costs 'may' lower feedstock; costs for' ethanol
production. Refinements and new, higher value uses for co-
products are an even likelier source of new revenues and
could reduce the cost of ethanol by as much as plant

innovations.

23

2.3.2 Capital cost

Another component of producing ethanol is capital cost,
which includes plant erection and modifications, replacement
of worn equipment, and a rate of return on the initial
investment.The primary capital expenditure in a wet milling
plant, which accounts for the sizeable cost difference
compared to dry milling plant, is recovery equipment for
removing the germ, oil, and fiber from the corn kernel. In
dry milling plants, nearly half of the capital expenditures
are for equipment to process co-products.

In both dry and wet milling plants, high capital costs
are associated with steps where the process slows or
requires special equipment. Technological innovations which
speed up the process or replace expensive equipment are
therefore likely to lower capital costs. The construction of
new ethanol production plants and the adoption of new
technologies at existing plants is likely to lead to cost
reduction.

Improved enzymes and fermenter designs can reduce the
time needed to convert corn to ethanol and lower capital
costs. Membrane filtration can allow the recovery of high
value co-products such as lactic acid. Adoption of these and
other innovations in the next five years is expected in new

ethanol plants constructed to cope with the new demands

24

resulting from "Clean. Air .Act" stipulations for cleaner
burning fuel. Cost reduction of 5-7 cents per gallon are
possible in the near term (1996). Older' plants, having
already invested in equipment, will be unable to take full
advantage of capital cost savings, but can still save 3.5-5
cents per gallon. Improved enzymes and fermenter designs can
reduce the time needed to convert corn to ethanol and lower
capital costs.

2.3.3 Operating cost

Operating cost constitutes the final component of
production costs and includes energy, enzymes, labor,
management, taxes and insurance. Many technological
innovations have focused on reducing operating costs raising
the efficiency of inputs, particularly energy. Energy is the
greatest operating cost, so innovations which conserve
energy have been among the first adopted in the industry.
Most large ethanol plants now receive steam and electricity
at low cost from co-generation facilities which
simultaneously produce both. The industry also has reduced
energy costs by adopting more efficient means of alcohol
dehydration. However, large savings in energy costs are not
likely because the present level of efficiency is close to

optimal.

25

The second largest operating cost is the cost of yeast
and enzymes. Although this cost has fallen considerably in
the past few years, particularly for enzymes, research may
further lower the cost of propagating these organisms or
reduce the volume needed. The use of improved yeast strains
has lowered processing cost by more than 50%. It is
estimated that over the next five years the average cost of
ethanol production in the industry will decline by 5-7 cents
per' gallon. because of further' technological innovations.
Improved yeasts, which tolerate high concentrations of
ethanol, can further lower energy costs.

In the long term, i.e., by year 2001, a state-of-the-art
corn conversion plant could reduce costs further by
improving fermentation process and converting part of its
co-products into ethanol through the conversion of corn
fiber. Adding these technologies to a new plant will
increase cost savings to 9-15 cents per gallon (7-11 %
savings over the cost of production in a current state-of-
the-art plant). Additional cost savings may’ result from
incremental improvements to the production efficiency or
unexpected breakthroughs, but are likely to be small

compared with the projected savings, especially in the near

term.

26

2.4 Modifications required on the engines and related
system

Conventional spark ignition engines and their related
systems are designed and manufactured keeping in view the
properties of gasoline. Use of any alternative fuel will
require certain modifications depending upon the change in
properties. These may be major modifications performed by
the manufacturer or minor ones done by the user.

There are two ways of using ethanol in spark ignition
engines. The first is to use it as a blend with gasoline, in
different proportions,‘in vehicles which are either modified
or unmodified. The use of such a blend has the effect of
producing' a .slightly leaner' mixture, which. improves the
economy of vehicles with carburetors set rich. The second
way is to operate vehicles on pure ethanol which requires
major modifications on the engine and the fuel system.

A 10% blend of ethanol reduces the volumetric heat
content by approximately 3.5% and result in leaning the
mixture by a like amount. The main fuel metering jets in
carburetors, of nearly all the vehicles, are fixed and only
the idle jets are adjustable.

The stoichiometric air/fuel ratio of the blend will
differ from that of gasoline as the percentage of ethanol in

the blend is changed. Therefore, as more ethanol is added to

27
the blend, the air/fuel mixture of a carburetor becomes less
favorable and drive ability of the vehicle is affected which
is worst at part load. It can be overcome by increased
heating of intake manifold, either by exhaust heating,
coolant heating or both.

Modification of the carburetor or fuel injection fuel-
air metering system will be required to convert a spark
ignition engine to run on straight ethanol. In some engines,
it might involve simply enlarging the carburetor main
metering jet to compensate for differences in the energy
content and stoichiometry between ethanol and gasoline.

There are several reasons for enlarging the main
metering jet of a carburetor in an ethanol fueled engine.
The first reason is that ethanol requires air to fuel ratio
of 9:1 to ignite in the engine where as gasoline requires
15:1 ratio. The difference between ethanol and gasoline is
about 40%. Ethanol carries oxygen in the fluid, where as
gasoline does not, that may explain why ethanol requires
less air to ignite. Another reason is the difference in
weight of ethanol and gasoline. Ethanol weighs 6.6 pounds
per gallon; gasoline weighs 6.1 pounds per gallon. Even at
6.6 pounds, alcohol is a thicker fluid than gasoline and
will not flow readily through a jet designed for gasoline.

Although the difference in the two fuels by weight is only

28

10%, alcohol has only two-thirds of the energy that gasoline
has. To compensate for this, one must add one-third for
energy loss and 10% for difference in fuel weight; that
necessitates the 40% enlargement of the main jet. However,
the carburetor needs proper calibration for the fuel being
used to obtain completely satisfactory engine performance at
all operating ranges.

Ethanol offers about twenty numbers improvement in
research octane number and ten numbers improvement in motor
octane number. This should lead to a possible increase in
compression ratio of the order of two to four, but this is
not easily achieved because the pre ignition tendency of
ethanol is much worse than the gasoline. Although, the pre -
ignition problem can be mitigated to some extent by using
cooler' running spark. plugs, but it ‘tends to reduce the
practical increase in compression ratio below that which
could apply if only the octane numbers were important.

Ethanol is corrosive and reacts with lead, copper,
magnesium, aluminum, brass, some plastics and elastomer. The
components in a conventional fuel system which are likely to
be attacked are the fuel tank (ternplate, lead/tin coated
steel), fuel pump» diaphragms, carburetor and fuel gauge

floats, carburetor and fuel pump castings, and some sealing

rings and washers. These items may require replacement

29
and/or repair depending upon the amount of ethanol being
used.

Experience with. gasohol has shown that the solvent
properties of ethanol loosen corrosion and dirt from the
walls of fuel tanks and automobile fuel lines. This makes it
advisable to flush and dry all storage tanks used with
ethanol-gasoline blends. Vehicle fuel tanks, particularly
with older vehicles, should be flushed with ethanol or the
blend and the fuel filter be replaced after the first or
second tankful. In addition, ethanol blends have led to the
cracking of polyamide filter housings and to the degradation
of polyurethene and polyester bonded fiber glass. These may
require replacement as and when required.

Alcohol fuels are particularly sensitive to water
contamination and may require special efforts to assure the
distribution system is water tight. Ethanol often vaporizes
less readily than gasoline. This often results in difficult

cold engine starting at temperatures below 40°F and poor

distribution of the air-fuel mixture to the engine cylinders.
Volatility problems, like others associated with fuel

alcohol, can also be solved by appropriate fuel and ignition

system modifications.

30

2.5 Comparison of fossil fuel energy consumed in producing
gasoline/ethanol

This comparison is based on the consumption of fossil
fuel energy only. All the data used in this calculation is
directly or indirectly related to the fossil fuel. Any other
factor, that may be affecting production of gasoline or
ethanol such as solar energy for corn, cost of transporting
crude or corn to the respective plants etc is not being
considered. Ethanol can be obtained from a fermentation of a
number of crops but only corn is being considered in this
work. The data used pertains to the state of Michigan or near
by states.

2.5.1 Gasoline

Yield per bbl of crude 45.8%

Energy per bbl of crude 5.8 x 106 IBtu

Gallons per bbl = 42

Processing energy 10% of crude

Gal of Gasoline _ Gal of Gasoline x bbl of crude

Btu bbl of crude Btu

 

 

 

Gal of gasoline/Btu

0.453 x 42/(5.8 x 10%

Gal of gasoline/Btu 3.32 x 1045

Processing energy

0.332 x 10*5 gal/Btu

Net energy

3.652 x 1045 gal/Btu

31

2.5.2 Ethanol

Since the energy consumed in the processing of ethanol

was not available, it has been assumed that it is equivalent

to that consumed in refining of gasoline. Data used in this

calculation is:
Gallon of Ethanol per Bushel of Corn
Bushel of Corn per Acre
Amount of Fertilizer (Ammonia) per Acre
Gasoline consumed per Acre
Amount of Natural Gas used in Ammonia

Lower heat valueyof Natural Gas

Lower Heat Value of Gasoline

Processing energy

2.5.3 Calculation

2.5.3.1 Fertilizer based

2.6

115

220 lb

10 gal

1 m3/Kg

1000
Btu/ft’of NG
116,485
Btu/gal
0.332 x 10‘

gal/Btu

Gal of fifth _ Gal of Eth JK811331101 of corn" Acre x lbm of fertx ft’ of NC

Btu Bushel of corn Acre lbm of ten: fc3 of NG

Btu

Gallon of Ethanol/Btu = 2.6 x 115 x (1/220)

x(2.2046/35.315)x(1/1000)

= 8.484 x 104

32

2.5.3.2 Gasoline based

Gal of Eth 3 Gal of Eth xBushel of cornx Acre J"Gal of Gasoline
Btu Bushel of corn Acre Gal of Gasoline Btu

. = 2.6 x 115 x (1/10)X(1/116485)

0.256 x 104

Net gallons of ethanol/Btu 8.484 x 10*

+ 0.256 x 104
+ 0.033 x 104

8.773 x 104

CHAPTER 3

3.0 Conclusion

It has been found that vehicles consume more ethanol
blended gasoline than gasoline when compared on the basis of
their heat values only. The fuel consumption increases as the
quantity of ethanol is increased in the blend. However, less
fossil fuel energy is consumed in ethanol blended gasoline.

Calculation, for: the jproduction_ of Ethanol and
Gasoline, based on fossil fuel input only show that ethanol
requires much less fossil fuel energy input than gasoline. It
must be appreciated that solar energy is free for ethanol and
this input remains un accounted for. This difference is
likely to change if exact amount of fossil fuel energy
required for processing is available.

Although presently use of ethanol as motor spirit is
not economically competitive with gasoline, however, the new

technologies in the industry, innovations in the production

plants, development of markets for co—products, use of

33

34
available farmland and improved agriculture technologies to

i I I
ncrease corn production, will soon bring two fuels at par

35

 

?

 

 

 

 

 

Parameter Ethanol Gasoline
Consumption Dis-advantage Advantage
Emission Advantage Dis-advantage
Consumptio/Energy Advantage Dis-advantage
Production process Catching Up Advantage
Engine Modification Dis-advantage Advantage

 

 

Energy Cost

 

Advantage

 

 

Dis-advantage
J

 

Table 3.0. Showing Comparison of Ethanol and Gasoline

A Guide to Commercial Scale Ethanol Production
and Financing , SERI/ SP-751-877, Solar Energy
Research Institute , Golden,Colorado, 1981.
Agriculture Statistics , U.S. Department of
Agriculture 1992.

Basic Petroleum Data Book , Petroleum.Industry
Statistics ,Volume XIV , Number 1 , January 1994
American Petroleum Institute , washington D.C.
B. Mary and T. Claud , " Alternative Fuels for
The Combustion Engine ", Final Report- May 1990 ,
Michigan Legislature.

C. A. Stakes and G. D. waterland , " Ethanol and
Methanol : How The Costs Compare " , Technology
Review July 1981.

C. L. Knapp , " Alcohol - Gasoline Blends as
Vehicular Fleet Fuels " , SERI / SP-7SS-1005,
1981.

E. D. Kane , " Refining will see changes by

2000",Petroleum / 2000 , August 1977.

36

I

10.

11.

12.

13.

14.

15.

16.

37

E. F. Obert , " Internal Combustion Engines and
Air Pollutions " , 1973.

" Fuel From Farms _ A Guide to Small Scale
Ethanol Production ",SERI / SP- 451-519 ,

Solar Energy Research Institute , Golden ,
Colorado , 1980.

J. A. Bolt , " A Survey of Alcohol as Motor
Fuels" 1980.

J. H. Gary and G. E. Handwerk , " Petroleum
Refining " , 1994.

M. E. Salassi , N.D. McBride , and R.A.

Pelly, " Representative U.S. Corn Farms ,1987 " ,
Economic Research Service , Statistical Bulletine
No.820 , 1987.

M. Medici , " The Natural Gas Industry " .1974.
N. Hohman and C. M. Rendleman , "Emerging
Technologies in Ethanol Production " , Agriculture
Information Bulletin Number 663, 1993.

R . H . Thring , " Alternative Fuels for
Spark-Ignition Engines " , Fuel and Lubricants
Meeting San Fransisco , California , 1983.

R. M; Bata and V. P. Roan , " Effects of Ethanol

and/or Methanol in Alcohol-Gasoline Blends on
Exhaust Emissions " , Journal of Engineering for

Gas Turbines and power , Vol. III , 1989.

38

17. S. B. Nott , et al. , " 1992 Crops and Livestock
Budgets Estimates for Michigan " Agriculture
Economics Report No. 556 ,January 1992.

18. V. D. Hunt , " The Gasohol Hand Book " ,1981.

19. W. E. Tyner , " Food Versus Fuel ? - The Moral

Issue in Using Corn for Ethanol " ,Technology

Review ,July 1981.

 

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