----- Original Message ----- From: Michael Allen <[EMAIL PROTECTED]> Subject: Re: [biofuels-biz] skin on biodiesel
> Thanks Paul, > > I'll try to follow that up. > > Currently in Thailand, we wash the BD made from stearin with almost indecent > haste. > > Of course, if the skin comes from near the BD/glycerol interface, we should suspect > methanol evaporating from the glycerol. So is the skin on the top of the BD or really on > top of the glycerol? Others participants have already raised the matter of > 1) whether it is BD soluble or > 2) water soluble > 3) Affected by separation time, > 4) Disappears in the wash. > > Are we sure we are all talking about the same skin???? > > Thanks again Paul ----- there is nothing like a few facts to muck up a perfectly good > theory! : - ) > > Michael Allen > > Michael, building new processor . At the moment I make BD in 10l batches in 15L plastic drums hand shaken. The mix is poured into 20L plastic pails where it is stirred intermittently over a period of an hour. The settling time for the glycerine reduces with each stir. As the drums are filled a thin skim/film forms on the surface of the BD. This film readily redissolves. (perhaps its polimerisation under the influence of the air ). The only problems I have had with the BD/glycerine interface is when using high levels of alkali (above titration levels) in the single stage alkali process. I like to drain the glycerine as soon as possible as extended contact of BD/alkaline glycerine tends to form a jelly like material at the interface which makes washing very difficult (emulsification). As long as the glycerine is drained off early, have found that higher than titration levels of alkali give easier washing. Prefer to use higher than titration levels of alkali, gives lower yield volume but a Bd with lower SG and viscosities. Hope that helps, Paul Gobert. Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://webconx.green-trust.org/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
