Hi Keith, What about the European standards such as DIN or Austrian ? they require at least 96.5% metylester content; is this beyond homebrew?
--- Keith Addison <[EMAIL PROTECTED]> wrote: > Hi all, > > Keith asked me offlist for directions for the acid > number determination. > Here's the info, forwarded from an offlist exchange > I had with Todd > Swearingen a few weeks ago, about this and other > quality standards stuff... > Mark > > > >Date: Thu, 10 Oct 2002 00:55:01 -0400 > > > > > >Maria, > > > >Looking at the ASTM standards as the benchmark for > home brewers, > >most of the standards can be met simply by > preparing and washing > >the fuel well. > > > >A) Flash point (130*C minimum) will be relatively > consistent for > >all feedstocks, presuming reaction completion and > the alcohol is > >removed. If the alcohol is distilled or washed out > this is a > >non-problem. > >B) Water and sediment (0.050 maximum % by volume) > are > >non-problems with adequate settling times, > filtration and fuel > >reheating to ~120*F. (I don't suggest adding any > acid to clear > >fuel haze, as this will increase the acid number.) > >C) Free glycerin (0.020 maximum % by mass) is > removed and is a > >non-problem with adequate settling time and > washing. > >D) Total glycerin (0.240 maximum % by mass) is > reduced to nil and > >is a non-problem if sufficient reaction time is > permitted (mono-, > >di- and tri-glycerides are all cracked), sufficient > caustic is > >used (not excess, as this can raise the acid number > by cracking > >methyl esters back to FFAs) and sufficient settling > time is > >given. > >E) Kinematic viscosity (1.9 - 6.0 mm2/s at 40*C) > will also be a > >non-problem if the total glycerin content (Items C > & D) has been > >resolved and the acid number is not elevated by > imprudent use of > >caustic, causing back cracking of esters to FFAs > (higher > >viscosity than B-100). > >F) Sulfated ash (0.020 % by mass) is a > non-controllable when > >using straight base, as the only sulfur in the > equation is > >derived from the parent feedstock. When using an > acid/base > >process the sulfuric acid used in the > esterification step is > >neutralized by the base. The resulting salt is > soluble in the > >water wash and should be a non-problem with proper > washing. > >G) Sulfur (0.05% maximum by mass) - see Item F. > B-100 is > >essentially sulfur free. > >H) Phosphorous content (0.001% maximum by mass) is > a > >non-controllable relative to the parent animal or > plant feedstock > >and is a non-problem beyond that as long as > phosphoric acid is > >not used to clear fuel haze. Phosphoric acid can > also increase > >the acid number (acid + FFAs). This is why either > adequate > >settling times, and slightly warmed fuel are the > better options > >for clearing fuel. > >I) Acid number (0.80 maximum milligrams of KOH per > gram of fuel) > >will remain low if acids are not added to the fuel > either pre, > >post or during washes (either to "ease washing"(?) > or clear fuel > >haze) and if caustic is not used in excess, which > causes higher > >numbers of esters to break down to FFAs. > > > >Other standards, such as distillation temperature, > copper strip > >corrosion, cetane number and cloud point are for > all practical > >intents and purposes properties that will fall > within ASTM > >standard if the fuel is prepared and washes are > conducted > >properly. > > > >As for a poor person's method of checking acid > number....It can > >be conducted in the exact same manner as the > titration of the > >original feedstock, save for the substitution of > biodiesel for > >oil. Keep in mind that the assay of the KOH being > used will need > >to be taken into consideration. If the assay is 90% > for example, > >the number of milligrams of KOH per gram of oil > should be > >multiplied by the % purity. > > > >One can also assay the KOH themselves with an acid > titration. But > >that's a bit out of the realm of probability for > most shadetree > >biodieselers. > > > >The in house chemist (Ph.D. in chemistry) suggests > that a careful > >titration using the same method as the original > feedstock > >titration should get you within + or - 10%, perhaps > + or - 5% if > >one is really precise. > > > >You could also use other indicators such as > phenophtalein to > >titrate the fuel. This would reduce the margin for > error from the > >"pH method," as pH is really designed for aqueous > solutions. > > > >Hope this helps. > > > >Todd > > > > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Biofuels list archives: > http://archive.nnytech.net/ > > Please do NOT send Unsubscribe messages to the list > address. > To unsubscribe, send an email to: > [EMAIL PROTECTED] > > Your use of Yahoo! Groups is subject to > http://docs.yahoo.com/info/terms/ > __________________________________________________ Do You Yahoo!? Everything you'll ever need on one web page from News and Sport to Email and Music Charts http://uk.my.yahoo.com ------------------------ Yahoo! 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