Dear Murilo, Conventional corrosion needs a freely ionisable solvent such as water for attack to take place.
There is some water in methanol and in vegetable oil but it is dissolved and not ionised. (Try measuring the pH to see what I mean!) As a consequence, pumps handling methanol and oil, even though there is some sodium hydroxide around, will not be seriously corroded. The same is not true for the water washing system. True chemical attack can still occur however and I would recommend that cast aluminium alloy pump parts be avoided. It is more in your area of study (ie the microstructure of materials), but I would expect some hydrogen formation along the grain boundaries in impure aluminium which would IMO could cause embrittlement. 25/02/03 09:37:45, "Murilo D. M. Innocentini" <[EMAIL PROTECTED]> wrote: >Hi everyone, > >Could anybody please tell me if the mixing pump for a small-scale biodiesel >processor needs a special requirement in terms of corrosion/chemical attack? >Does the base catalyst type affect its performance? It seems from several >pictures in the web that even a simple washing maching pump works in this >case. Is it true? > >Thank you all, > >Murilo D.M. Innocentini > >Group of Engineering and Microstructure of Materials >Department of Materials Engineering >Federal University of Sao Carlos >Via Washington Luiz, km 235 >13565-905 Sao Carlos - SP - Brasil >Tel. 00 55 16 260-8253 >Fax. 00 55 16 261-5404 > > ------------------------ Yahoo! Groups Sponsor ---------------------~--> Rent DVDs Online-No late fees! Try Netflix for FREE! http://us.click.yahoo.com/bbvVKB/oEZFAA/46VHAA/9bTolB/TM ---------------------------------------------------------------------~-> 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/
