I found an oil source and have been doing double time research to design a system in 2 weeks. I have been back and fourth on biodiesel or SVO. To treat SVO a lot of the guys just let the oil sit for an extended period of time as I understand. Can you do this with biodiesel? After you pre filter it, react it, recovery the methanol, drain the glycerine then can you just let it sit in a tank for a month or two to wash and dry it? If it works on SVO to get all the free particles and suspended water out it sould work on biodiesel too right? Maybe add some biocide to keep bad stuff from growing.

I'm not a SVO guy, I'm sure others will be along shortly to help on that.

However, I don't think "it works on SVO" to get all the stuff out by settling.

I believe that SVO works because it is heated in the tank, and more importantly is purged out of the engine and fuel lines with regular diesel. I am pretty sure you still have a lot of impurities in it.

Likewise, not all of the impurities will "settle out" of biodiesel.

Some people don't worry about the impurities and run the BD without washing. I worry about them. You could well find cleaning solvents,or just about anything in SVO. In the Biodiesel, even after reaction, you will have some soap dissolved in it, as well as glycerin and some mono and di glyceride's.

Washing will get most of them out because the "stuff" is more sloluable in water than oil (BD) so it attaches to the wash water and separates from the BD.

Another thought;

When you or we talk about impurities, we have to know what we mean.

In SVO, you have impurities such as french fries, meat particles, batter and water. You also have impurities such as fatty acid, preservatives, and possibly cleaning chemicals.

I think settling and filtering may remove most if not all of the food parts.

I do not think the chemicals will be reduced by settling. In either application SVO or biodiesel.

However, if you process BD, and then wash, you can remove almost all of the chemicals.

Yea, a lot of people prefer to process into biodiesel and let it settle for a time before using.
It brings us right back into the debate "to wash or not to wash" which everyone has their own opinion about. Neither is right/wrong but washing the fuel is always going to improve fuel quality (In my opinion, here we go again)

In SVO, if you're just looking to speed up the process of having (some) of the impurities settle out faster, just heat the oil up a bit and anything that will settle, will do so much faster.

In your case, it sounds like you are still deciding between SVO and Biodiesel, and keep in mind what you plan to use the fuel in. (is the engine you plan to run it in known to handle SVO well?)
I choose not to run SVO for many reasons, fuel quality being the main one. With biodiesel you have better controll of what you put in your tank. SVO/WVO has impurities that will never just settle out as Mr fixit says.

Actually I'm really starting from scratch. I don't even own a diesel vehicle, yet. Now that I have an oil source that is my next step. I am leaning toward biodiesel because WVO warm up time is too long for the my often short trips. Anyway it's sounds like washing by settling can't happen. But what about drying by settling. Is that more feasible? If so how does does it take?

spray dry into the top of your container, use pump wich wihh run about 500 watts an hr., use heater spear to heat the bio to speed the process, 1250 watts an hr. 4 hrs max. that 1750 watts an hr, wich is bit under 2 KW/hr. so total of about 8KW. Elec @ about 12cents a KW so cost be about $1 to dry in under 4 hrs for a batch of maybe around 40 gallons or so.

Trc

I'm with TRC,
I spray my "wet" BD in a pipe. In the top of the pipe is the wife's old hairdryer. Hot air over the BD droplets make this process very quick. (<1hr) Then let it cool down overnight (high melters can settle out) Filter (5µm) and there you go.

After washing BD, it will dry just from sitting in an open toped container. Must be open top to air though.

However, it will take much longer to dry.

Spray drying 30 gallons of BD will get it completely dry in 2 hours. Sitting would take days, maybe weeks.

Important to remember: However you do it, BD MUST be completely dry before you use it. The water in it can cause problems in your motor. When it is completely dry you can read a typed page through a mason jar full of BD. It should look like crystal sparkling water. No opaqueness allowed.

Ok. Thanks for the feedback. I'm have a few more details to work out with my processor. Does anyone know how long it has to settle for to get all the water out? I'm not sure why it has to be open to dry. I thought water just sank to the bottom? And does it need to be completly open top to the air or just have a breather valve on it? There was also a comment earlier about SVO. Just for the record alot of the SVO guys actually wash their oil. Filter it, wash it, let it sit for a while then it's ready. That's with SVO anyway.

quote:

Originally posted by eou_edu:
I'm not sure why it has to be open to dry. I thought water just sank to the bottom? And does it need to be completly open top to the air or just have a breather valve on it?

The big droplets of water will "just sink". But the biodiesel will absorb some of the water. After processing from oil to biodiesel, the biodiesel will be 'cloudy' with absorbed soap, leftover mono and di glycderides, and methanol. Then you wash to get the 'leftovers" out which will cause the BD to absorb water. "Clean Biodiesel" at this point will look like orange juice.

It will only dry by being exposed to air. That is why it has to be in an open container. It has to be exposed to air, the more air it is exposed to the faster it drys. That's why people "spray dry" to speed up drying by rapidly exposing it to air.

I think we all assume that you have read over on the tutorial side.

If you haven't already, please go look at Biodiesel community.
Lots of great information there that some of the folks here wrote.