I'm just started dry washing for the frist time last night. I'm using a metering pump that pumps 10gph. Im using hard wood sawdust. When I frist started the biodiesel came out crystal clear. I tested in a five gallon bucket before putting in a 55 gallon drum. I filter about 15 gallons last night, and when I looked at it this morning it was really cloudy. It was cold last night in the low 30's. Any ideas what could do this. Should I start over?
I mixed 1 ml of distilled water with 1 ml of my biodiesel at room temperature then stirred a lot. I checked the pH of the water and it was above 10. Potassium soap pH is about that much. I'm not an expert. I think if you mix 1 ml of your dry washed biodiesel with 1 ml of distilled water, then stir a lot, measure the pH of the water with a proper paper pH test strip. If your pH is very close to 7 then I expect your dry wash is working. Did you demeth and allow settling before dry washing? Some people say testing the pH of biodiesel is useless, but I expect it can be one test of purity if a distilled water extract is obtained. thanks
So I demeth the fuel before drywashed it. I heated the fuel up and let it sit for 24 hours or so. I havent test the PH yet of the fuel. It's kinda werid it came out clear, and then 12 hours later its cloudy? .
When you pass bio thru sawdust for the first time it collects resin and fine sawdust and makes the bio cloudy.
When i use a new batch of sawdust i fill the sawdust drum enough to cover the sawdust and let it soak for 1-2 days. Then i open the bottom valve and drain into another drum and settle 2-3 days to let the resin and sawdust fall to the bottom. It is then sent back to the sawdust drum to filter as usual.
Demething or removing excess alcohol after the crude biodiesel is produced should cause a lower layer to form under the biodiesel. It takes time for the lower layer to fall out, it doesn't happen completely for maybe days at lower temperature. You said you demethed your crude biodiesel, but did you let it cool and sit for a day or more so a lower layer could form, then remove the lower layer, then dry wash. Are you using sodium hydroxide or potassium hydroxide?
So Im seeing good results right now the fuel is really clear and clean. I added two filters before and after the sawdust filter. I did a PH test on the clean biodiesel and got around 6.5 6.8.
I heated the fuel for 24 hours at 130 degress, then i pump it out into 55 gallon drums. They sat in drums for a week cause I didnt have the dry wash set-up yet. what is the lower layer? and how did you remove it? I'm using Sodium hydroxide.
Is there a way to stop the reaction in the fuel. When the barrels sat for a week i notice on the bottom of the barrels there is a 1/4 inch layer of glycerin on the bottom of the barrels.
That is what is supposed to happen. As the residual methanol is removed from the biodiesel the suspended soaps drop out of solution during the settling stage after the demething phase. What you have on the bottom of your drum is soaps that have dropped out of solution.
** Biodiesel Glycerine Soap - The Guide
- on 5 continents helping people make & sell soap from the Biodiesel Glycerine.
Ok I'm going to test the fuel for soap tonight. Im prob should make a tank cone tank just for unfiltered raw fuel so I can get the glycerin out easier.
Thanks for the info