Soda Keg Resin Tower Plans
By Rick Da Tech
Sunbreak Biofuels posted this dry wash design on the Infopop forum. We've added it here with their permission.
The Amberlite user guide calls for the following:
- 3:1 Column height-width ratio
- A flow rate of 0.36gph/lb dry resin
- Resin raised 2" from bottom with #80 (175 micron) screen
Projected flow rate of 10 gallons/hour.
The column needs to be able to handle pressure up to 25 psi, be easy to clean and be made of a biodiesel compatible material. For an added bonus the perfect column would be practical for the typical backyard brewer, be constructed from readily available materials and scalable for the small scale producer.
Cornelius kegs, used to dispense fountain drinks, are stainless, handle up to 125 psi, have a large hatch in the top, and have dry connect fittings with a pickup tube routed straight to the bottom They are readily available used for about $25 each..
There are two versions of the Cornelius keg, a 22" keg and a 27" keg. The short one has a height to width ratio of 2.44:1 and the tall one is 3.38:1. The 22" keg will hold about 5.8 gallons, while the 27" keg will hold about 5.3 gallons. Either would allow for 10 lbs of resin to be added to each column and still have sufficient room for 300% expansion.
10 lbs of resin gives a maximum flow rate of 3.6 gallons per hour. Three in parallel will meet the 10 gallon per hour target with a 10.8 gph maximum.
Basic three keg Design
Using one keg will give you a flow rate of about 3 gallons per hour. We're going to do a three keg setup for about 10 gallons per hour. To do a single keg, you will just remove two kegs from this design.
- Start with biodiesel which has had the methanol already removed.
- Filter to 20 microns while pumping into top gravity feed tank.
- Taking biodiesel from bottom, through a 100 micron pickup screen and filter through a 5 micron paper filter.
- Then pass biodiesel through the Cornelius keg towers flowing from the top down to the bottom.
- Use a needle valve on the output of the kegs to regulate the flow rate.
- The biodiesel should be at 65F to 75F and if colder needs to be heated before passing it through the resin.
Here we see the setup using totes for upper and lower tanks. Biodiesel drains from the lower tank, through the blue 5 micron filter, then through an inline heater then through the Cornelius kegs and back to the top of the lower tote through a needle valve.
This setup is located outside in a Northern State and needs heating to bring the biodiesel and resin up to the operating temperature. He is using an inline coffeemaker heater to supply the heat needed.
Filling the keg
- Add 2 lbs of glass marbles to the bottom of the keg.
- Starting with an 10" square of #80 mesh stainless, cut a 9" circle with scissors.
- Use a hole punch to put a 1/4" hole in the middle of the screen.
- Install a small rubber grommet in the newly created hole.
- Cut a piece of the cheapest flimsy garden hose you can find to the exact inside circumference of the keg.
- Curl screen and place inside keg and carefully place at bottom over settled marbles.
- Replace stainless pickup tube, oil to easily slide through screen grommet.
- Let garden hose act as a bumper around the perimeter of the screen.
- Add 1.5 gallons clean biodiesel to keg.
- Pour 2 lbs increments of Amberlite in top of keg, rotate as you pour to disperse the Amberlite around the outer perimeter of the screen. This will also help squash the garden hose to the outer edge under the weight of the Amberlite.
- After you add 10 lbs of Amberlite backflush the column at 2.5 gph with clean biodiesel. If there is the slightest bit of methanol or soap in the biodiesel used to flush it will precipitate out and clog up the resin bed. After two hours and all air being purged, the column is ready to use.
Bill of Materials
For each Cornelius Keg you will need:
- 1 ea Five gallon stainless steel Cornelius keg
- 2 ea quick connect fittings + hose barb nipples
- 4 lb glass marbles
- 10 ft 1/4" clear hose
- 10" x 10" #80 mesh stainless screen
- 1 ea rubber grommet
- 21" of flimsy garden hose
For each setup you will also need:
- 1 each needle valve
- 1 each 5 micron paper filter and mounting head
- 1 ea 100 micron pickup screen
Economics and Final Notes
At the time of this writing each keg tower cost about $130 for the parts and resin and will clean about 320 to 640 gallons of biodiesel. That translates into 20 to 40 cents per gallon for the first load of resin and about 11 to 22 cents per gallon starting with your first resin change. 18 cents per gallon for the first load and 7 cents per gallon on the refills have been reported. Your mileage may vary.
Please note that this design is based on settling for a week or more before passing it through the resin. Incomplete settling will shorten the life of the resin. Experience has shown that settling for four weeks without using a prewash results in the resin lasting for 800-1100 gallons.
The resin depends on methanol being present to act as a solvent for the soap. If the soap is not completely dissolved in the biodiesel, it will tend to clog up the resin. Settling is the best way to reduce the soaps to the level that the methanol can properly dissolve. Longer settling times will reduce the mass of soap in the biodiesel. One test to determine if enough of the soaps have settled out is that the biodiesel will be clear, not cloudy or turbid.
If you use your top gravity tank as a settling tank, it would be better to use a standpipe and take biodiesel out of the middle of the tank rather than from the bottom. That way any soaps and glycerin that has settled in the tank will not be deposited in the resins, shortening the life of the resin.
Ion Exchange Resin Tower Examples
This Giant 7 foot tall resin tower comes with a full 73 pound charge of Purolite and will flow 30 gallons per hour. Built from a stury steel construction including Flanged construction allows for easy clean out and resin replacement. 1" inletstop and bottom and with stainless steel pressure gauge and stanless ball valves. Made in the USA and available from Northerntool.com
This twin tower system is commercially available and targeted directly at home brewers. The biodiesel flows from left to right. It is pumped out of the drum with a metering pump at a rate of about 9 gallons per hour. The next stop is the 10 micron Cim-Tek spin on filter. The biodiesel next goes to a pressure relief and gauge combo. Not shown is the tubing going from the relief valve back to the source tank. The flow goes from the bottom of the first tower to the top of the second. There is a 2 micron Cim-Tek final polish filter before it's deposited in the finished product drum.