Hi all. I am new here and have been reading everything I can on drywashing. I am getting ready to start building my processor, basing it on Murphys mm63 plans. My question is on how big to build my drywash towers. I have access to 6" and 8" black iron tube, or 12" stainless tube. Also how many should I have, 2 or 3. I am going to slowly build everything through the winter and start processing in the spring.
2, 6inch diameter by 54 inch tall towers with wood chips in the first and 21 lbs, Purolite or DWR10 in the other is a good setup. That setup will do 10 gph or more. You can get an inexpensive metering pump on our web site or look on ebay for an LMI pump. I would go with 2 towers only because resin is expensive and the wood chips will bring your soap levels almost or down to zero before it hits the resin. You could also just use 2 towers with wood chips to cheapen it up more.
Purolite recommends a 24" depth of resin to allow for adequate residence time, although much of this has been done away with the advent of the use of hard wood chips. Even so, if you do use resin keeping with the manufacturer's recommendation is still a good practice.
My own system uses a 200L drum of chips followed by lead/lag beds of Purolite PD206 resin. I final polish using a CAT 2 micron fuel can. Pics and explanation on my website ( in the sig line)
Thanks for the replys. I will use chips in both towers to help keep it cheap. Another thing I am wondering about. Is it better to have the BD pumped into the towers from the bottom or the top. I have seen it both ways on here and don't know which is better.
JasonThis message has been edited. Last edited by: blurr95,
It is best to keep your drums filled with biodiesel to avoid any potential for spontaneous combustion occurring. The flow rate must be sufficiently slow enough to offer good residence time.
My 200L drum is top fed, bottom outlet and then it goes into 2 reverse flow tanks. The reverse flow works just like a fuel filter where the fuel goes in the top but must pass through the entire volume of media and then reverse its flow up a center pipe. I have pics with explanation on my site in the dry wash section.
If you use two 6 inch diameter towers that have a 50 inch bed depth you can get a 33 lb bag of bd zorb that will fill both towers. Recomended flow rate is 16.5 gph max, 10 gph is a good rate to start. You will also clean approx 1000 to 1600 gallons before you need to change the BD Zorb.
Our towers are set up to do up flow or down flow. We choose to up flow. No need to back fill towers and let sit to purge air out. All air gets purged out during up flow. With BD zorb or wood chips I would use a 2 micron biotech Hydroglass filter. It will get any water and slow to a stop when exhausted and trap fine wood particles.
If you do use resin remember to make the tower to handle resin expansion. Example, 24 inch bed depth the tower should be 50 inches min. Purolite and DWR10 both double in size and I have found out sometimes more. Thats why we make 54 inch column towers to handle all resins.
Thanks again for the replies. Turner, I had looked into the BD zorb on your site already and will probably go with that if I have a hard time finding chips locally. Do I just fill the towers up as full as I can, or do I need to leave some room for expansion. Legal, I have looked at your site several times. I like your setup.
One thing you have to be carefull doing is MIXING media.Using any Ion resin when Soap content is above 600PPM can cause high acid values in your biodiesel. Ion resin should never be used when soap content is above 600ppm,when soap content is at or above 1000ppm you will not only raise acid number but you will ruin very expensive resin.There have been several wood type medias produced since the introduction of echo2pure. Such as Arbor pure/ Arbor,BD zorb/Turner and Dryclean by Heartland Biodiesel.Also up flow and down flow can be done with any tube or column the big difference is in how they flow and the contact time the biodiesel has with the media.Up flow is not reccomended when using ion resin as you may disturb the resin bed causing a fractured flow. How does this effect tower size? Simple each media has its specific flow rate as well as each batch of biodiesel has different soap content.Decide how many GPM or GPH you need to accomplish your goal then Find out how much of your specific media is required to do this.Figure your cubic feet required factering in the amount of swelling if any? Wood does not swell much but ion resin does hince not reccomended mixing together as they also have different contact times required so flow rates will be different for each. If you decide to use both use seperate columns. I have a Heartland Biodiesel Drycln system.This consistes of (3) 12" diameter towers (2) using DryCln media (upflow)30KG each and the 3rd using Ion resin(downflow). I run 4GPM through the first (2)until soap falls below 300PPM then flow though last tower at (1)GPM.This cleans my 250 gallons of fuel from 2500ppm to below 60ppm in approx 6 hours. Hope this helps...This message has been edited. Last edited by: lorgeme,
On the subject of residual soaps; I have tested some batches as high as 3,000ppm going into demething and then 800 ppm into the chips drum but coming out at ZERO ppm and final polished by the resin, which at that point really didn't have much to do.
This has been the repeated result of RolfQuo's experience as well; anything going in the chips at or below 800ppm comes out at ZERO ppm after a single pass.