The years of experience I am referring to is my
understanding that B100 has been available in Europe
for years. The CEN standards have apparently ensured
satisfactory fuel quality. I'm not aware of the
politics of rapeseed oil or of its cost.
The debate seems to revolve around the question of
whether the CEN standard for oxidation stability is too
high or the ASTM standard is too low.
Your expertise is recognized.
What is an acceptable OS-IP value?
What oils might meet this acceptable value?
I've run cars on biodiesel made from various and
unknown oil types. (These include soy.) My fuel is rarely
stored longer than a month. I avoid metals like copper and
zinc in production, storage, and delivery of fuel.
If there is a question of oxidation the fuel goes to my
heating system, not the cars.
Tom
> It is nice indeed that someone finally took this side
of
> biodiesel
> quality to debate. The years of experience that you are
> referring to is
> something that I have not seen documented anywhere, can
> even less judge
> the relevance. It is well known that the CEN 14214 is
> tailored for rape
> seed oil as raw material and there has been a lot of
> critisism for that.
> The reason for this tailorship is unknown but it smells
> politics and
> even nationalism. What is even more disturbing is that
> the use of
> anti-oxidants is not aloud in the CEN, in order to meet
> the parameters.
> The truth today is that good rape seed oil is so
> expensive that almost
> no biodiesel producer can use that raw material.
> It is good with quality, of course, but defining
quality
> is another cup
> of tea.
>
> On Tue, 30 Apr 2013 08:59:41 -0400 (EDT), "Thomas
Kelly"
> <ontheh...@fairpoint.net> wrote:
>>> The latest national survey of 100% biodiesel (B100)
>>>"blend stock" samples by the U.S. Department of
Energy's
>>>National Renewable Energy Laboratory (NREL) found that
>> 95% >of the samples from 2011-12 met ASTM International
>> fuel >quality specifications.
>> ......
>>> "The survey showed a major improvement over results
>>> from
>>> previous years," NREL Senior Chemist Teresa Alleman
>>> said.
>> {samples}
>>> .... were tested for a range of critical properties,
>> such >as free and total glycerin content, metals
>> content, and >cloud point
>> that could have an immediate impact on operability.
>> "immediate impact on operability"
>> I'd like my diesel engine to run trouble-free for
>> many
>> thousands of miles.
>> Why do vehicle manufacturers maintain warrantees on
>> their vehicles that run on biodiesel (B100) that meets
>> CEN standards (European Committee for Standardization),
>> but void warrantees on the same vehicles when run on
>> B100
>> made in countries that used ASTM standards (American
>> Society for Testing and Materials)?
>> A major concern has been the tendency of the fuel to
>> oxidize. This tendency is indicated by Iodine Value
>> (IV) which is part of CEN standards, but not ASTM
>> standards.
>> All vegetable oils and the biodiesel made from them
>> will
>> eventually oxidize forming a varnish-like goo. Iodine
>> value has been presumed to accurately indicate the
>> tendency of oil, and the biodiesel made from it, to
>> oxidize.
>> Many Biodiesel fuel standards specify an upper limit
>> for iodine value of biodiesel. For example, Europe's
>> EN14214 specification allows a maximum of 120 for the
>> Iodine number, Germany's DIN 51606 tops out at 115. The
>> USA ASTM D6751 does not specify an Iodine value.
>> It might be noted that the European and German
>> specifications result in a defacto ban on Soy based
>> biodiesel as it's iodine value is above the acceptable
>> limit.
>> While the European standards' iodine value measures
>> the
>> number of double bonds in the hydrocarbon chains, there
>> is some dispute as to whether or not it is a reliable
>> indication of actual oxidation tendency. (Position of
>> the double bonds in the molecule, contamination with
>> metals, and other factors may play a significant role).
>> ASTM now includes an "Oxidation Stability Index"
>> (OSI).
>> It attempts to determine actual oxidation of biodiesel
>> as
>> measured by changes in electrical conductivity after
>> "air
>> flow" exposure.
>> It is interesting to note what the CEN and ASTM
>> consider to be acceptable oxidation tendencies, whether
>> determined by by Iodine Value or OSI. The CEN accepts
>> Iodine Values below 120, which allows for biodiesel
>> made from rapeseed and other oils, but not from soy.
>> I believe CEN now includes OSI values (6.0 and up) that
>> allow for the same rapeseed biodiesel, but still
>> excludes
>> biodiesel made from soy. The ASTM accepts biodiesel
with
>> much lower OSI values, which, coincidently, includes
>> biodiesel made from soy oil.
>> While some say that the CEN standard is "arbitrarily
>> high". I'm not sure "arbitrary" is appropriate when
>> applied to a standard that is based on years of
>> experience. More likely, the ASTM standard that allows
>> for soy-based biodiesel is dangerously low.
>> Note: Veg oil and the biodiesel made from it are
>> relatively stable. Once oxidation starts the rate of
>> oxidation rapidly accelerates. This point at which
>> oxidation becomes clearly measurable is called the
>> "Induction Period" (OS-IP). The higher the number, (in
>> hours) the better the oil or biodiesel "resists"
>> oxidation.
>> Note: The low OS-IP number allowed in ASTM standards
has
>> been defended by some by citing a study in which
>> biodiesel
>> made from various veg oils (with various OS-IP's)
fueled
>> engines which were ultimately disassembled and found to
>> have "no significant differences in build-up on
>> surfaces."
>> This suggests that little or no oxidation occurred
>> during
>> the high temp and pressure of combustion in the
engines,
>> regardless of oxidation stability values.
>> The problem with this is that a major concern with
>> oxidation involves storage. Although the test to
>> determine OS-IP is performed on biodiesel at elevated
>> temp (110C) and with enhanced exposure to air, the
>> resulting OS-IP is given in hours. Fuel with low OS-IP
>> values that which has been stored for long periods may
>> well contain varnish-like products of oxidation that we
>> wouldn't want to put in our fuel tanks.
>> Consider that fresh biodiesel mixed with older fuel
>> in
>> a storage tank, might well be exposed to the very
>> oxidation products that will accelerate oxidation. It
>> would seem prudent to go with high, yet achievable
>> Oxidation Stability values even if soy oil, a
>> convenient and profitable feedstock, may have to be
>> excluded from biodiesel destined for our vehicles. (I
>> have used biodiesel made from soy to heat my house and
>> provide domestic hot water for about 10 years w/o
>> problem. It's easier and cheaper to change a nozzle on
>> a burner than to replace injectors/fuel pumps on cars.)
>> An interesting reference article:
>> http://www.oleotek.org/FichiersUpload/Softsystem/NRCan-OLEOTEK
>> Study of the Rancimat Test Method in Measuring
>> the Oxidation Stability of Biodiesel Ester and Blends
>> NRCan project # CO414 CETC-327
>> By
>> David Berthiaume
>> Alain Tremblay
>> OLEOTEK Inc.
>> Tom
>> ----------------------------------------
>>> http://www.sciencecodex.com/nrel_survey_shows_dramatic_improvement_in_b100_biodiesel_quality-110510
NREL survey shows dramatic improvement in B100
>>> biodiesel
>>> quality
>>> Posted By News On April 16, 2013 - 5:00pm
>>> The latest national survey of 100% biodiesel (B100)
>> "blend
>>> stock"
>>> samples by the U.S. Department of Energy's National
>>> Renewable Energy
>>> Laboratory (NREL) found that 95% of the samples from
>>> 2011-12 met ASTM
>>> International fuel quality specifications. The ASTM
>>> standards serve as
>>> guidelines for industry and are designed to ensure
>> quality
>>> at the pump
>>> for consumers â along with reliable operation of the
>>> nation's vehicles
>>> powered by biodiesel blends.
>>> "The survey showed a major improvement over results
>>> from
>>> previous
>>> years," NREL Senior Chemist Teresa Alleman said. "In
>>> our
>>> 2007 survey of
>>> B100 biodiesel, less than half of the samples met
>> quality
>>> specifications. More stringent quality requirements,
>> along
>>> with the
>>> voluntary BQ-9000 quality management program, are
among
>>> the reasons for
>>> this marked improvement."
>>> B100 is not commonly used as a fuel, but is blended
>>> with
>>> petroleum
>>> diesel, typically in blends up to 20%, and has been
>>> part
>>> of the
>>> industry's steady growth in the past decade. B100
>>> production increased
>>> from 27.9 million gallons in 2004 to more than 1
>>> billion
>>> gallons in 2012.
>>> For the most recent survey conducted from August 2011
>>> to
>>> February 2012,
>>> NREL researchers collected fuel samples from 53
>> producers
>>> and 14
>>> terminals from across the United States. Terminals
from
>>> the East and
>>> West Coasts, the Rocky Mountain region, and the
Midwest
>>> were tested for
>>> a range of critical properties, such as free and total
>>> glycerin content,
>>> metals content, and cloud point that could have an
>>> immediate impact on
>>> operability.
>>> To ensure product quality, ASTM published the first
>>> B100
>>> quality
>>> standards in 2002. ASTM International does not enforce
>>> fuel quality, but
>>> it is a leader in the development and delivery of
>>> international
>>> voluntary consensus standards. Its specifications are
>>> frequently adopted
>>> by state and local governments to ensure fuel quality
>> and
>>> are monitored
>>> by industry members. NREL is among the organizations
>>> participating in
>>> the development of standards.
>>> Source: DOE/National Renewable Energy Laboratory
>>> http://www.nrel.gov/news/press/2013/2171.html
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