Page 26 - Fuels & Lubes International 2014 - Q2

FUELS & LUBES INTERNATIONAL Volume 20 Issue 2 26
any diesel engine, the bar for test-
ing and the data required is a lot
higher than if you have a fuel that’s
used for one specific thing and one
specific application,” Howell said.
One of the reasons why the
biodiesel industry is backing the
proposed changes to the standard
is that some suppliers have used
raw vegetable oil as blend stock,
according to Howell. Doing so
saves money, as it minimizes
processing. Unfortunately, it also
could mean problems down the
road, including fuel stability and
clogging of internal engine parts.
Not wanting to end up with losses
due to engine failure and a black
eye with the public, the biodiesel
industry wants to ensure that what
is stamped as a D975-compliant
fuel is suitable for use. Thus,
they’re pushing for a set of specific
constraints within the standard that
will eliminate the chance for spec-
compliant biodiesel being blamed
for problems caused by other fuels.
“Looking forward, there is
a series of parameters that may
not currently be spelled out in
the ASTM document that could
become important as new fuels
are developed,” Howell said. These
include surface tension, bulk
module of elasticity and elastomer
compatibility. As a result, future
modifications to the standard are
almost certain, in part because
new fuels will demand that such
parameters be specified.
Cal Hodge, president of con-
sulting firm A 2nd Opinion, works
with the renewable hydrocarbon
diesel industry. He noted that
D975 does not specify a source for
the hydrocarbon and that, there-
fore, the hydrocarbon oil does not
have to be derived from petroleum
crude. That opens the door to
renewable diesel, by several mea-
sures a high-quality fuel.
“It’s just about a perfect diesel
fuel. It comes from a low-carbon
source. It reduces NOx emissions.
It burns cleanly when you put it in
diesel engines. It’s doing everything
that you would want a fuel to do.
Some of the competitors don’t quite
do all of those things. And it’s very
stable,” he said.
OEMs respond
“ASTM standards will have
to evolve,” said Roger Gault,
vice president of regulatory affairs
An effort
abandoned
Not every change to diesel-
related standards makes
its way through ASTM’s
approval process. The same
is true of attempts to create
new specifications.
Shell, for instance, for years
championed a specification
for paraffinic middle
distillate oil with public
discussion of this work
appearing at least seven
years ago. However, engine
makers, fuel suppliers and
other relevant stakeholders
were unable to reach an
agreement. Consequently,
the effort was tabled.
“Shell no longer leads
this effort, since February
of 2013, and no one else
has stepped up to be the
champion. The proposed
spec covers synthetic diesel,
as well as hydrotreated
vegetable oils and
renewable diesel fuels,” said
Ralph Cherrillo, a Shell fuels
technology advisor who at
one time was secretary of
ASTM D02.
This doesn’t mean that a
spec for the fuel won’t be in
place. The European Union’s
TS 15940, for example,
covers these types of diesel.
Without an ASTM standard
out there, the European
standard is likely to prevail,
according to Cherrillo.
at the Chicago-based Truck and
Engine Manufacturers Association
(TEMA). “However, this will
have to be done without creating
additional risks. That’s why the
OEM group has been taking steps
to ensure this.”
“We’ve been supportive of ef-
forts to clarify what is or is not a fuel
that is being defined by the stan-
dard,” Gault said. “We’ve worked
extensively with the biodiesel
industry about what we believe are
acceptance criteria for methyl esters
and blend levels of methyl esters.”
Doing so involves expanding
the number of parameters and
the number of different tests to
characterize a fuel. Historically,
petroleum-based fuels were
hydrocarbons with some level
of aromatics. Summarizing the
whole distillation curve could be
done by finding the T90 point, the
temperature at which 90% of the
volume of the fuel evaporates.
With the new fuels, that simple
snapshot will no longer be enough.
Thus, there must be additional
clarity in the standard, Gault said,
and the change being balloted is a
step in that direction.
OEMs have to deal with
changing fuels and evolving
standards, and that presents
a challenge on different levels.
End users, for instance, may have
regulatory requirements that
demand the use of a low-carbon
footprint or low-emission fuel.
At the same time, they want
engines to run, whether in cars and
trucks traveling down the highway,
off-highway earth-moving
equipment or stationary systems.
“Fuel represents the highest
operating cost for Caterpillar’s
customers,” noted Hind Abi-Akar,
Caterpillar’s fluids technical expert.
The company has taken the stance
that a fuel can be used if it meets
Caterpillar’s own specification, the
latest version of D975 or the latest
version of the European Union’s
EN590. In part this is done so as
to accommodate traditional
fuels, as well as newly developed
renewables and alternatives.
“As these fuels are introduced
into the market, we want to
ensure that our customers have
the information needed to select
the fuels and to apply them
successfully,” Abi-Akar said.
Donna Hoel