Continuing in the overly dramatic subject line for this thread vein... Well I went to weigh and then to dry and reweigh the samples I had, and found another annoying and very odd thing.
Here's a recap: a few weeks ago when I started experimenting with 'bubbledrying', I had taken some freshly washed fuel that was somewhat hazy, and I had put a hazy sample into a tightly sealed jar, then 'bubbledried' the rest of the fuel until it cleared up all the haze and the fuel was brightly crystal clear. We normally assume that clear (WASHED) fuel is a sign that the fuel has released all of the water that might have been dissolved in it from the washing process. I then put a sample of that presumably 'dried' and clear fuel into a similar size jar with about the same amount of air space as the first sample had gotten, and sealed it tightly as well. I thought it would be good to have the samples to show people the difference between dried and undried fuel. but within about two weeks I found that both samples gradually got hazy again, and this was at a fairly warm room temperature (cold will make fuel haze appear for various reasons, but that's not what was happening here) SO I was going to take both of the now-identical-looking samples, weigh them, then heat them to drive off any water, and then reweigh them to see whether one (which had previously been clear but then re-hazed) actually had less water content. It wasn't going to be a very accurate test because I only had a small sample of each (about 200 ml each). I couldn't do a bigger test because my most recent batch of washed fuel had 'cleared' on it's own in two days (in a sealed drum, at that) without any bubbledrying and I didnt' have any hazy fuel left. the other factors here are that the stuff in the sample jars was probably not the best-washed fuel I've produced, and that I'm boring you all with this cause I'm trying to figure out if the haze clearing experienced in bubble drying is actually 'drying', or this clearing is actually some kind of chemical reaction between something in the air and something in biodiesel (and guessing that whatever that reaction is, it's reversible). ANyway I went to do that weighing bit today, and found another odd thing: one -but only one- of the samples had gone crystal clear (which is pretty normal for washed fuel that sits for a few weeks like this one had) Unfortunately I never labeled which was which (since originally it was 'obvious' at the time which was hazy and which was clear), so I don't know if it was the bubbledried one or the normally settled one. Weird stuff, any thoughts? I will continue with this next time I wash some fuel to the same 'specs' and have some that's hazy... It occurred to me that an extra night of bubbledrying exposed the biodiesel to an extra night of cold and that some kind of tallow esters precipitation happened that the main tank of drying fuel experienced but that the first sealed sample did not. But I had this clearing and then gradual hazing happen twice now with different samples, and one of the times the hazy sample jar had sat outside along with the vat of stuff that was bubbledrying, and both got similarly cold. Don't know if it is at all relevant to the current clearing (at different rates) that I;m seeing in the samples. Below are a couple of replies I got on biofuel and biofuels-biz. One of them is relevant here and the other is just about the measurement I was trying to do today... Mark ************************************ from David Teal: To: <biofuels-biz@yahoogroups.com> Subject: Re: [biofuels-biz] bubble drying- big correction Mark, When you raised the bubble-dry issue a few weeks back, I wasn't convinced that the main action was necessarily water evaporation. I tend to store samples of biodiesel in capped 2 litre Dr. Pepper style plastic bottles, and had noticed that if an air space is left above the liquid, it always reduces in volume, partially collapsing the bottle. My surmise has been that a oxidation process was at work, where the oxidation products are liquid, and the oxygen is removed from the air. I have also noted that if the sample strarted hazy, it would clear at the same time, not always with a preciptated residue of water or anything else. It would be interesting to test for oxygen depletion in the air pocket. I did try a rudimentary test to extinguish a burning taper (like we did at school chemistry lessons), but this was not conclusive. David T. 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/ from Paul Gobert - we were discussing measuring water content in biodiesel by weighing, then boiling, then re-weighing: At 07:05 PM 1/26/2003 +1000, you wrote: >----- Original Message ----- >From: "girl mark" <[EMAIL PROTECTED]> ><snip> > > Like I said I haven't done this qualitatively before- so I don't know if > > the amount of water sufficient to form haze in the fuel is a sufficient > > mass of water for me to weigh on a .1g sensitivity scale. any ideas on >what > > is the weight of the water if it is present at for instance 1200 ppm in a > > 100 ml sample of biodiesel? > > > > Mark ><snip> >1200ppm in 100ml is 120000/1,000,000ml ie.0.12ml, which will be equivalent >to the smallest unit of sensativity on your ballance, very difficult to >measure accurately. If you do try this use as light a containor for the BD >as possible (beaker would be good). Also try to use a larger volume of BD up >to the capacity of your scales in order to improve the accuracy. > >Regards Paul Gobert, > [Non-text portions of this message have been removed] 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/
