Spring/Summer 2010 - Robert M. Kerr Food & Agricultural Products ...

10 | fapc.biz
Dimethyl Ether:
A clean alternative fuel, but ..
A
s new regulations
requiring lower
engine exhaust
emission levels are being
implemented in the United
States, interests in alternative
fuels, new engine
designs, and fuel injection
systems have conformed
to the new rules. Dimethyl
ether (DME) has been
considered as a clean alternative
transportation
fuel since mid 1990s.
DME is a simple ether
that has the same number
of carbon, hydrogen,
and oxygen atoms in its
chemical structure as ethanol.
Addition of oxygen
containing compounds or
“fuel oxygenates” such as
DME and ethanol to the
petroleum fuels reduces
carbon monoxide and
ozone levels in the atmosphere.
DME is a good
fuel oxygenate because of
its high oxygen content,
35 percent by weight.
DME burns with a visible blue flame
and is sometimes referred to as “PRO-
ZONE,” “Ice Blue,” or “Blue Fuel.”
The physical properties of DME
are similar to liquefied petroleum
gases (LPG) propane and butane.
Since DME is a gas under normal
conditions, it needs to be stored in
pressurized vessels and handled in a
similar manner to LPG. Unlike methane,
DME does not require an odorant
addition to monitor potential gas leaks
from a system because of its natural
sweet ether-like odor.
Petroleum residues, coal bed
methane, coal, natural gas, and biomass
are some of the feedstock used
for DME production. Although natural
gas has been the main feedstock for
the last decade, research and development
work on DME production from
biomass specifically from forest residues
is gaining momentum.
To produce DME, the feedstock
of choice is first gasified to produce
syngas, which contains mainly carbon
monoxide and hydrogen gas. Then,
the conversion of syngas to DME can
be carried out in one reactor, which
is referred to as “direct process” or
DME is a simple ether that has the same number
of carbon, hydrogen, and oxygen atoms
in its chemical structure as ethanol.
through an “indirect process” involving
synthesis of methanol from syngas
followed by methanol dehydration to
produce DME.
DME is currently used in production
of many chemicals. It is also a
popular component in aerosol products
such as hairsprays and spray
paints, replacing chlorofluorocarbon
(CFC)-based propellants, which are
associated with ozone depletion in the
atmosphere.
DME is reported to be safe for
consumers and employees working
in production plants at 1000 parts per
million level in the air. DME is a good
alternative fuel to replace petroleum
diesel because of its high cetane number,
fifty-five or higher, soot, sulfur
free combustion, and excellent blending
properties, which allow blending
with LPG and diesel fuel.
Richard LeBlanc of Chemrec
USA said, “DME offers a very high
reduction of carbon dioxide emissions,
around 95 percent, compared to conventional
diesel fuel, and it can be produced
with very high conversion efficiency
at relatively moderate capital
cost and can be made from a variety of
renewable materials.”
The BioDME project (www.thenewsmarket.com/volvogroup)initiated
and coordinated by Volvo Group
and supported by several technology
providers including Chemrec, Delphi,