This is a direct quote from a Metalurgical Engineer I know. I am speaking from experience with another fellows reactor - 2 years old and still going - most tanks will be 5xxx series but again - I advocate - TEST IT. I dont advocate this as a desired Choice of materials but PE instead.
Jim "5XXX series aluminums have good corrosion properties and form a passive layer faster than some of the other series aluminums. They contain magnesium alloying which is a good property for corrosion and ship halls are usually made from 5XXX series aluminums. To keep the aluminum from corroding, do not have the aluminum touching other metals because the aluminum will start acting as an anode and be sacrificed to protect the other metals. Your operating temperatures are also variable which increase your rate of reactions for corrosion. Your operating temperatures may not be interfering with the passive layering process on the aluminum and the passive layer is protecting the aluminum like it should. Other processes may have more particulates in the solution being processed which causes erosion corrosion and then the passive layer is being removed faster than it can heal if there is mixing going on in the tank; making aluminum tanks a bad idea for storing their solutions. I need some more back ground information to get down to the nuts and bolts on both questions. Methanol, CH3OH, OH- is looking for a positively charged ion other than the carbon atom. So the iron from the steel bonds with OH- ion due to the activity rates at a thermodynamic level and corrodes the steel. Methanol is relatively reactive solution, you can tell by the flammability signs on the barrels from shipment so that is why most of the methanol that is shipped these days is in polyurethane-ethylene tanks and most of the steel barrels all leak." >From: Joe Street <[EMAIL PROTECTED]> >Reply-To: biofuel@sustainablelists.org >To: biofuel@sustainablelists.org >Subject: Re: [Biofuel] Back to the topic...New BD stuff >Date: Wed, 17 Jan 2007 09:49:31 -0500 > >Are you sure about that Jim? > >I use KOH as a etchant for aluminum. Works like gangbusters. I would >assume methoxide would do the same. > >Joe > >JAMES PHELPS wrote: > >>Mike, >>The answer is yes. If it is high alloy, even better. What happens is >>aluminum forms >>an oxide on its skin and it becomes very resistant to chemical corrosion. >>The trick is to be sure >>that you let it breath the inside of the tank. It needs an oxygen fix >>every so often to maintain the layer. >> Good luck >> Jim >> >> ----- Original Message ----- >> *From:* Mike Weaver <mailto:[EMAIL PROTECTED]> >> *To:* biofuel@sustainablelists.org >> <mailto:biofuel@sustainablelists.org> >> *Sent:* Saturday, January 13, 2007 2:27 PM >> *Subject:* [Biofuel] Back to the topic...New BD stuff >> >> I have managed to score a 50 - 60 gallon aluminum tank with >> fittings - >> perfect for a processor. >> I also have a 67 gallon (looks like lucite) circular fish tank. >> >> I know MOX does not like aluminum, and have heard BD does not like >> Lucite or Lexan or whatever this. >> However, BD is fine in aluminum tanks. >> >> I am wondering if I can use the aluminum tank as a processor, being >> careful when introducing the MOX - I've made BD in HDPE2 containers >> plenty (even the stray plastic bottle way early on). >> >> So, any thoughts on the aluminum as processor and the fishtank as >> a wash >> or settling tank? >> >> -Weaver >> >> _______________________________________________ >> Biofuel mailing list >> Biofuel@sustainablelists.org <mailto:Biofuel@sustainablelists.org> >> >>http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org >> >> Biofuel at Journey to Forever: >> http://journeytoforever.org/biofuel.html >> >> Search the combined Biofuel and Biofuels-biz list archives (50,000 >> messages): >> http://www.mail-archive.com/biofuel@sustainablelists.org/ >> >>------------------------------------------------------------------------ >> >>_______________________________________________ >>Biofuel mailing list >>Biofuel@sustainablelists.org >>http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org >> >>Biofuel at Journey to Forever: >>http://journeytoforever.org/biofuel.html >> >>Search the combined Biofuel and Biofuels-biz list archives (50,000 >>messages): >>http://www.mail-archive.com/biofuel@sustainablelists.org/ >> >> >> >_______________________________________________ >Biofuel mailing list >Biofuel@sustainablelists.org >http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org > >Biofuel at Journey to Forever: >http://journeytoforever.org/biofuel.html > >Search the combined Biofuel and Biofuels-biz list archives (50,000 >messages): >http://www.mail-archive.com/biofuel@sustainablelists.org/ > _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
