Does BioDiesel freeze?
 

just a question, but @ what temp does BioDiesel actually freeze? How about WVO? As far as I remember, water is one of the few substances that expands when it becomes solid. The reason I'm asking is our processor has a low spot that doesn't drain completely. If the Glycerin were to freeze in there, would it break the pipes? The low so far has been about 27 degrees. We are going to re-plumb it anyway to get complete drainage, but was just curious. thanks

Biodiesel doesn't really freeze. It will get thick and gell, but as soon as the temp increases it will revert back to good fuel. Gell temps depend on what the original oil was. If your using KOH the glycerol will not freeze, it will just get very thick, like heavy grease.

thanks, we are using KOH. Probably a good idea to get all the glycerol out of there anyway so it doesn't get pumped in with the good stuff.

I dont think you will be able to move the frozen glycern from the low spot with just the pump. That happened to me last winter, I had to use a heat gun on the pipe to liquify the glycern so the pump could move it.

We are in the process of re-plumping so that there won't be a low spot, but will be a slight downhill grade to the drain. A pain due to all of the plumbing being black pipe that we cranked down real good. Never thought about the problem until now live and learn I guess.

got er done, what a pain in the ...

Glad ya got it fixed.

I'll take a stab at the original question. No, biodiesel itself does not 'freeze', but it will become fairly solid at a low enough temp - no expansion issues though (good memory).

Now the temp it gels at is quite variable depending on the feedstock. Pure canola oil has the lowest cloud point/gel point IIRC, it is close to 0*F. Hydrogenated oil is 'solid' at room temp and 'Partially' Hydrogenated oil depends on the kind of oil and the extent of 'partial' I guess, but expect the B100 to cloud slightly lower temp than feedstock.

I always keep a sample from each batch outside where I see it in the morning. When it starts to get real cold, I can tell before I get in truck if fuel is starting to cloud. If its gettin cloudy - I add a few% more diesel and then take a sample from filter bowl before shutdown. Monitor sample and add diesel if req'd...

We try to seperate out the lightest VO all year to use for 'winter-blend' B100. We have made batches that did not cloud until lower temp than pump diesel w/this stuff!

Thanks for the info. Most of our sources are using canola as far as I know. Will mix different ratios when it starts to get colder.