1
MEMORANDUM
DATE:
June
22,
2004
SUBJECT:
Dual
Fuel
Conversion
Systems
FROM:
Tanya
Ali,
Alpha­
Gamma
Technologies,
Inc.

TO:
Sims
Roy,
EPA
OAQPS
ESD
Combustion
Group
The
purpose
of
this
memorandum
is
to
present
information
obtained
regarding
dual
fuel
conversion
systems
for
compression
ignition
(
CI)
stationary
internal
combustion
engines.
Information
received
from
manufacturers
of
dual
fuel
conversion
systems
and
other
information
available
on
the
world
wide
web
regarding
dual
fuel
systems
available
for
stationary
CI
engines
will
be
presented
in
this
memorandum.

Background
In
a
CI
engine,
a
high
boiling
point
liquid
fuel
is
injected
into
the
combustion
chamber.
The
fuel
ignites
when
the
air
charge
has
been
compressed
to
a
temperature
sufficiently
high
for
auto­
ignition.
In
a
dual
fuel
engine,
liquid
fuel
(
typically
diesel
fuel)
is
used
for
ignition
and
gaseous
fuel
(
typically
natural
gas)
is
used
as
the
primary
fuel.
Dual
fuel
engines
typically
run
on
80
percent
or
more
natural
gas
and
20
percent
or
less
diesel
fuel.
Other
fuels
such
as
liquified
natural
gas
(
LNG)
and
compressed
natural
gas
(
CNG)
may
also
be
used
instead
of
natural
gas.
Some
of
the
benefits
associated
with
using
dual
fuel
engines
are
lower
emissions
and
lower
fuel
costs
while
retaining
the
power
associated
with
a
dedicated
diesel
engine.
The
following
are
some
of
the
companies
that
offer
dual
fuel
conversion
systems:

°
Innovative
Technology
Group
(
ITG),
°
Energy
Conversions,
Inc.
(
ECI),
°
Clean
Air
Power,
°
Hybrid
Fuel
Systems,
and
°
GTI/
Altronic
Controls,
Inc.

Innovative
Technology
Group
The
system
offered
by
ITG
can
retrofit
diesel
engines
of
any
type,
age,
size,
application,
and
at
any
location,
to
natural
gas/
diesel
dual
fuel
operation.
The
2
company
uses
the
process
of
fumigation,
which
blends
the
natural
gas
with
air
before
entering
the
engine.
The
conversion
system
can
replace
80
percent
of
the
diesel
fuel
with
natural
gas.
Fuels
such
as
CNG,
LNG,
wellhead,
bio,
and
digester
gases
can
also
be
used.
The
substitution
does
not
derate
the
engine
and
the
engine
remains
in
principle
a
diesel
engine.
Should
the
gas
supply
become
unavailable,
the
engine
will
run
on
diesel
until
gas
is
restored.
According
to
ITG,
the
dual
fuel
system
responds
faster,
runs
better,
operates
under
normal
operating
temperatures,
and
requires
fewer
oil
changes.
Emissions
of
nitrogen
oxides
(
NOx)
can
be
reduced
by
as
much
as
60
percent
and
particulates
are
reduced
to
near
"
clear"
conditions
following
installation
of
the
conversion
system.

Energy
Conversions,
Inc.

Energy
Conversions,
Inc.
develops
natural
gas
retrofit
conversions
for
medium
and
high
speed
diesel
engines.
The
company
has
the
Economizer,
a
dual
fuel
conversion
system
for
the
industrial
four
stroke
diesel
engine
market.
which
converts
diesel
engines
into
diesel/
natural
gas
dual
fuel
engines.
Operation
on
90
percent
natural
gas
is
possible
while
maintaining
engine
efficiency
and
fully
rated
horsepower.
According
to
ECI,
the
Economizer
can
be
installed
on
existing
or
new
diesel
engines
and
diesel
operation
remains
unchanged.
Emissions
of
NOx
are
reduced
by
more
than
50
percent.
Diesel
particulate
matter
is
also
reduced.
The
Economizer
system
is
available
for
three
standard
models:

System
1:
150
to
300
kilowatt
(
KW)
(
200
to
400
horsepower
(
HP))
Single
Turbo
System
2:
300
to
1,000
KW
(
400
to
1,340
HP)
Dual
Turbo
System
3:
1,000
to
2,000
kW
(
1,340
to
2,680
HP)
Dual
Turbo
Smaller
and
larger
conversion
systems
are
also
available
according
the
company.

The
vendor
indicated
that
the
system
is
not
a
verified
technology
and
that
emission
certification
would
be
on
a
case­
by­
case
basis.
The
EPA
asked
if
the
system
is
applicable
to
stationary
engines
of
any
size
and
application.
The
vendor
replied
that
the
system
is
applicable
to
almost
any
engine,
however,
it
does
not
expect
to
convert
smaller
two
stroke
engines
such
as
the
Detroit
Diesels.
The
vendor
said
that
pipeline
natural
gas
is
the
preferred
fuel,
but
that
stored
fuel
would
be
possible
if
the
application
supports
it.
Propane
is
an
option,
but
it
is
not
preferred,
and
digester
gas
would
work.
The
EPA
asked
what
type
of
problems
and
limitations
are
associated
with
the
storage
of
CNG
and
LNG.
The
vendor
responded
that
problems
with
CNG
include
the
cost
of
the
tanks
and
the
lack
of
volume.
Most
of
the
volume
issues
are
eliminated
with
LNG,
however,
tanks
for
LNG
are
also
expensive.
The
EPA
requested
system
cost
information
from
the
vendor.
The
vendor
said
that
it
has
a
couple
of
basic
system
types.
The
Economizer
is
more
suited
for
four
stroke
engines
500
HP
and
up
in
size.
The
vendor
provided
a
cost
of
$
6,500
to
$
10,000
for
engines
up
to
2,000
HP
in
size,
3
plus
technical
support.
For
larger
stationary
engines,
such
as
6
megawatt
(
MW)
(
8,043
HP),
the
cost
would
be
$
50,000.

Clean
Air
Power
Clean
Air
Power,
formerly
Clean
Air
Partners,
offers
the
Dual­
Fuel
 
system.
The
system
makes
it
possible
for
diesel
engines
to
operate
primarily
on
natural
gas,
up
to
85
percent.
The
technology
is
offered
for
both
vehicle
and
stationary
engines.
Currently,
the
company
offers
the
technology
for
certain
models
of
Caterpillar
engines.
However,
according
to
Clean
Air
Power,
there
are
no
technological
limitations
in
adopting
this
technology
to
other
models
or
other
manufacturers.
Benefits
of
using
a
dual
fuel
system
include
lower
fuel
costs
and
lower
emissions
without
sacrificing
engine
performance
and
efficiency.
The
system
has
the
ability
to
revert
back
to
diesel
operation
if
natural
gas
become
unavailable.
The
system
may
also
run
on
CNG
or
LNG.
The
stationary
engines
operate
on
pipeline
natural
gas
but
can
operate
on
other
gases
as
long
as
the
gas
composition
is
accounted
for.
Vehicles
operate
on
CNG
or
LNG
because
of
the
need
to
store
large
amounts
of
gas
onboard
a
truck.
It
is
possible
to
use
propane,
however,
the
engine
would
have
to
be
derated
due
to
a
knocking
tendency
as
a
result
of
the
gas
composition.
The
EPA
asked
Clean
Air
Power
what
types
of
problems
and/
or
limitations
are
associated
with
the
storage
of
CNG
and
LNG.
Clean
Air
Power
responded
that
CNG
can
be
stored
safely,
but
the
equipment
required
to
compress
the
gas
sufficiently
to
levels
around
3,500
pounds
per
square
inch
in
order
to
store
the
gas
in
vehicle
tanks
can
be
expensive.
The
company
further
stated
that
the
technology
is
pretty
mature.
According
to
Clean
Air
Power,
more
challenges
are
associated
with
LNG
since
it
has
been
converted
into
liquid
form
through
a
cryogenic
process.
Tanks
that
are
specially
designed
to
store
LNG
can
only
keep
the
substance
in
liquid
form
for
a
certain
period
of
time,
and
after
that,
the
liquid
will
boil
off
and
has
to
be
vented.

The
EPA
also
requested
that
Clean
Air
Power
provide
cost
information.
The
vendor
said
that
system
costs
for
both
retrofit
and
application
on
new
engines
are
very
similar.
Costs
depend
on
several
factors
such
as
the
type
of
engine
model,
size,
desired
emission
levels,
efficiency,
and
balance
of
plant
requirements.
A
price
range
of
$
50­
90/
KW
($
67­$
121/
HP)
was
provided
by
Clean
Air
Power
for
the
conversion
equipment
only.
According
to
Clean
Air
Power,
the
dual
fuel
system
is
a
verified
technology
on
vehicles,
but
not
on
stationary
engines.
In
order
to
comply
with
CARB
regulations,
Clean
Air
Power
intends
to
verify
the
system
on
stationary
applications
also.

Hybrid
Fuel
Systems
Hybrid
Fuel
Systems
manufactures
dual
fuel
systems
for
medium
and
heavy
duty
diesel
engines
which
substitutes
80
percent
of
the
diesel
fuel
with
natural
gas.
The
system
operates
on
CNG
or
LNG
and
diesel.
Minimal
engine
modifications
are
required
and
the
power
of
the
original
diesel
engine
is
preserved.
The
technology
can
be
applied
to
4
new
or
used
vehicles
and
is
also
available
for
stationary
engines,
such
as
emergency
backup
generators,
however,
the
company
has
mainly
done
conversions
on
mobile
engines.
The
system
is
capable
of
operating
in
hybrid
mode
(
diesel
and
natural
gas)
or
in
100
percent
diesel
mode.
The
system
has
been
applied
to
engines
up
to
500
HP
and
is
specifically
designed
for
retrofit
on
mechanically
and
electronically
controlled
engines,
according
to
the
vendor.
The
current
price
of
the
dual
fuel
system
is
$
4,500,
which
does
not
include
installation,
which
is
about
one
day
of
a
trained
mechanic's
time,
the
tanks,
valves,
lines
and
controls
of
an
installed
fuel
system.
According
to
Hybrid
Fuel
Systems,
the
company
is
in
the
process
of
CARB/
EPA
certification.
Initial
testing
is
scheduled
to
be
completed
by
July
1,
2004
followed
by
a
1,000
hour
durability
test
required
for
final
verification.
Final
results
are
estimated
to
be
available
in
early
September,
according
to
the
vendor.
The
EPA
asked
the
vendor
what
some
of
the
problems
are
with
stored
fuel.
The
vendor
said
that
problems
are
typically
cost,
weight,
and
fuel
capacity
in
the
case
of
CNG.
Some
LNG
designs
have
had
problems
with
filling
completely,
"
weathering"
of
higher
hydrocarbons,
and
loss
of
thermal
vacuum.
Some
of
these
problems
can
be
corrected
by
design,
according
to
the
vendor.
The
vendor
indicated
that
it
cannot
verify
the
technology
on
propane
fuel.
Further,
the
vendor
does
not
have
experience
with
biogases,
but
would
anticipate
problems
with
these
fuels
since
they
are
inherently
free
of
higher
hydrocarbons.
The
system
has
been
applied
to
over
1,400
vehicles.

GTI/
Altronic
Controls
The
GTI
Bi­
Fuel
System
from
Altronic
Controls
converts
industrial
diesel
engines
to
dual
fuel
operation
by
substituting
up
to
80
percent
natural
gas
for
diesel
fuel.
Any
methane
based
gas
such
as
pipeline
natural
gas,
wellhead
gas,
and
biogases
can
be
used
to
replace
diesel
fuel.
No
modification
to
the
internal
components
of
the
engine
is
required
and
reduced
emissions
and
fuel
costs
are
some
of
the
benefits
associated
with
dual
fuel
operation.
In
the
event
of
lack
of
gas
supply,
the
system
can
revert
back
to
100
percent
diesel
operation.
The
conversion
to
dual
fuel
does
not
compromise
the
performance
of
the
engine.
According
to
GTI/
Altronic
Controls,
the
company
is
not
in
the
mobile
market
but
only
works
with
stationary
applications
in
the
power
generation
market
and
has
done
mostly
standby
generation
applications.
The
vendor
further
indicated
that
the
technology
can
be
applied
to
stationary
engines
of
any
size,
e.
g.,
from
engines
100
KW
(
134
HP)
in
size
to
engines
greater
than
2
MW
(
2,680
HP).
The
EPA
requested
cost
information
from
the
vendor.
The
vendor
said
that
equipment
costs
range
from
about
$
10,000
to
$
40,000
for
a
300
KW
(
400
HP)
to
2
MW
(
2,680
HP)
engine.
Operating
costs
are
a
function
of
fuel
prices.
5
References
1.
Peter
Calvert,
Hybrid
Fuel
Systems
to
Anna
Duncan,
EPA/
OAQPS.
Information
Regarding
Dual
Fuel
Systems.
Email.
April
29,
2004.

2.
Information
obtained
from
EPA's
Region
1
Website
at
http://
www.
epa.
gov/
region1/
assistance/
ceit_
iti/
tech_
cos/
innotech.
html.
May
5,
2004.

3.
Information
obtained
from
Innovative
Technology
Group's
Website
at
http://
www.
innotechgroup.
com.
May
6,
2004.

4.
Information
obtained
from
Energy
Conversions's
Website
at
http://
www.
energyconversions.
com.
May
6,
2004.

5.
Information
obtained
from
Clean
Air
Power's
Website
at
http://
www.
cleanairpower.
com.
May
6,
2004.

6.
Information
obtained
from
BAF
Technologies'
Website
at
http://
www.
baftechnologies.
com.
May
6,
2004.

7.
Information
obtained
from
GTI/
Altronic
Controls'
Website
at
http://
www.
gtiaci
com.
May
6,
2004.

8.
Hyung
Kim,
Clean
Air
Power
to
Tanya
Ali,
Alpha­
Gamma
Technologies,
Inc.
Questions
Regarding
Dual
Fuel
System.
Email.
May
7,
2004.

9.
Scott
Jensen,
Energy
Conversion
to
Tanya
Ali,
Alpha­
Gamma
Technologies,
Inc.
Questions
Regarding
Dual
Fuel
System.
Email.
May
10,
2004.

10.
Peter
Calvert,
Hybrid
Fuel
Systems
to
Tanya
Ali,
Alpha­
Gamma
Technologies,
Inc.
Questions
Regarding
Dual
Fuel
System.
Email.
May
26,
2004.

11.
Tanya
Ali,
Alpha­
Gamma
Technologies
to
Jason
Green,
GTI
Altronic
Controls.
Questions
Regarding
Dual
Fuel
System.
Telecon.
June
17,
2004.
