Dry Wash Tower Opinions - PeachParts Mercedes-Benz Forum

Stono-see-um · #1 10-08-2012, 06:26 PM

I've built my Appleseed, located methanol and lye and built a wet wash tank. I am a bit hesitant on the wet washing, not wanting to introduce water after processing. I've saved up enough money to buy a dry wash tower and media set up.

Question is, what does everyone use and what are your opinions on them? You can get 2 of the 6" towers from Duda Diesel, for the price of 1 from Utah Biodiesel.

jab0028 · #2 10-09-2012, 01:17 AM

Water washing, if done properly works great. You just have to make sure that all of the glycerine is removed beforehand otherwise you may get an emulsion. Also it helps if your water is hot. The hotter the better. Lastly you have to make sure that all of your water is removed. Heat again comes in handy here.

As far as dry wash towers are concerned, to me the cost of the dry media is not worth it. Everybody has their own way of doing things though. Looking forward to reading what others recommend.

spark3542 · #3 10-09-2012, 07:41 AM

I've done water washing for 7 years, dry washing for about a year.

Water washing...
I use fine misting nozzles to mist cold water over the BD in an open-topped barrel. Water is heavier than BD, so it will drop to the bottom, bringing the crud/soaps with it.

I do this for about 5 hours, or until the water that I drain off the bottom is clear or a very faint yellow, like weak lemonade.

Very easy to see visually when the wash process is complete.

I then bubble low pressure air through a pipe with holes in it submerged in the BD to dry it. I do this overnight...about 8 hours.

Drywashing...
I have a 6" tower with de-ionizing material and wood chips in it. I have a small pump inline to get it started, but then shut if off and let gravity/siphoning move the bd from wash tank through tower to finished tank.

This is much easier...no draining to tend to.

However, the finished BD looks exactly like the beginning BD, so i never know if the tower is effective. No visual to go by. Not having an ASTM lab in my house, it means I'm shooting in the dark. No feedback on when the drywash media is "saturated"

My 2005 CDI exhibited a lot of injector rap on the drywashed BD, so i only feed it waterwashed. The Cummins, the '83, and my home furnace are all fine with the drywashed BD.

Stono-see-um · #4 10-09-2012, 08:55 AM

I am mainly concerned about my cummins with water washing. I don't want any chance of water hitting my injectors at 25k psi. I am adding another 20 mic water separator to help avoid this.

The dry washing just seems so simple and quick. I have a friend in FL that has been dry washing for 6 yrs without any problems through his duramax. The small investment into the towers and resin seem like good insurance for my common rail. I can also get an almost unlimited supply of hardwood chips and sawdust.
Too many options..

spark3542 · #5 10-09-2012, 12:51 PM

Logic would dictate that adding water to a fuel would make it more likely that water is in your finished product.

In fact, the water is very much heavier than the fuel. It pulls the soaps down, so your tank after washing has a section of fuel on the top, a layer of soaps/crud, and a section of water below that. You drain off the water and soap, and use a standpipe to pull clean, non-watery fuel from above.

The other data point that I have is that my only common-rail vehicle (CDI) is the one that exhibited problems with drywash, but not with waterwash.

I would love to do only drywash for the simplicity and lack of wastewater, but I'm confident that my waterwash finished fuel is "cleaner"

bigblockchev · #6 10-09-2012, 08:15 PM

When you water wash you can see the fuel getting cleaner and the wash water too. I spray dry my fuel up to 170 deg which flashes off the residual water. When I am done I can see through 30" of fuel to the bottom of the processor. I could experiment with dry washing but why mess with something that works. If your fuel won't immediately separate from water when shaken in a jar it still has some glycerol in it . try it with both dry and water washed fuel & let us know which separates faster. Cheers

capflya · #7 10-10-2012, 05:05 PM

Another point to add is that biodiesel is hygroscopic. Even if you dry wash the fuel it will attract some moisture from the air. I have the sandy brae water test kit and dried my fuel after washing it. It was registering about 300ppm which is well within an acceptable level of water content per ASTM standard. I left the sample of biodiesel out in the garage and checked it a few hours later after it had cooled down and it was now registering at 600ppm water content. From what I have read this is normal and the fuel still was just as clear as it was when I first pulled it out of the processor so I went ahead and used it.

I would be interested to do this test on dry washed fuel but I do not know anybody locally with a dry wash setup...

Stono-see-um · #8 10-12-2012, 05:18 PM

Well... I may run a couple test batches water washing and experiment a little in both the Benz and the Cummins.

Anybody stir wash or just bubble and misting?
Washing: Journey to Forever

Also, for heating oil after washing, in the wash tank, I have a 120v submersion heater. Will this be OK for heating?

Thank you to everyone for your input so far! I have a little more confidence in water washing now.

capflya · #9 10-16-2012, 01:45 PM

The biopro does stir washing. If you run the automated wash cycle the first wash is just mist and settle, this is to reduce the chance of an emulsion. The 2nd and 3rd wash is mist then after the water is in the stirrer comes on for ~10 seconds and then shuts off. The bio is then allowed to settle so the water can be drained off the bottom.

So far so good.. I have just over 1000 gallons processed in this machine and run through my duramax/mercedes personally. Prior to me getting the biopro I was getting fuel from a buddy who has the same processor.

As for the heater you have I'm not sure, I have never used one of those but as long as it will get the biodiesel up to temp you should be good. Just needs to be hot enough for the water to evaporate off.

bigblockchev · #10 10-16-2012, 11:50 PM

To heat the fuel up from 60F to 160F in order to flash the water off takes me about 50 mins using a 6000W heater. This is for a 160L batch. A 120V heater will have a nominal rating of around 1500W max. This would take 4 times as long for the same vol of fuel, or the same time for a batch 1/4 size. the heating effectivness scales directly since the specific heat of the oil is the same. How big is your batch and how long do you want to wait to get it up to temperature. Cheers Dan

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