Have some kind of gel in my raw bio and need help identifying and fixing? I have attached a pic what the barrel looked like after I pumped out to run through the drywash system. I have not changed my process and have never seen this stuff before? I installed a new drywash system with new Thermax macro resin, washed bio is dark but it checks good on the 27/3 test, I can’t get the soap test indicator solution to turn blue so I assume that soap content is really very low, and there doesn’t appear to be any gel in the drywashed bio . The Phlipp test, however, appears to have a heavy layer of glycerides lying on top of the indicator solution. The raw bio, where the gel is at, passes the 27/3 test and soap content indicates 608 ppm. I am at a loss as to what causes this and am not running any until I can figure it out and fix it.
Here is my process:
Raw oil settles for 4-6 days, drain water and sludge (usually 65 gal. batch of good oil left)
Pump through 200 micron barrel top filter into clean barrel and into processor
Circulate and heat to 125F for 1.5 hrs.
Drain any water etc., usually not much, maybe half gallon or so
Start heat and circulate, titrate (avg. titration of 1.75)
Mix methoxide (21% methanol, 5.5g base + titration of NaOH)
Mix and process for 3.5 hrs. with two 720gph pumps at 135F
I use a single stage process with no prewash of any kind at this time
Circulate through 50 then 5 micron bag filters in series for 1.5 hrs.
Bubble wash for 6 hrs. usually at night then shut off in the morning
Drain glycerin, usually no more than a cup or so
Pump to drywash barrel as in the picture
Start pumping to the drywash towers and into the finished barrel.
I pump through a 10 micron GR filter as I am pumping to the drywash barrel, again leaving the drywash towers to the finished fuel barrel and through a 2 micron canister filter Bio-Tek as I am pumping to my truck or tractor.
I would appreciate any help I can get, Thanks! Sorry so long but I know the process questions would be ask anyways to do any effective troubleshooting.
Picture1.jpg (42 Kb, 50 downloads) Gel in raw bio
if there is a lot of water that has accumulated in your biodiesel (if left outside and water gets in) and you can see that there is a layer of water on the bottom of your bio then it could be microbial growth (if it has been left alone for a while) microbes grow at the interface between the water and the bio but could expand into the bio phase.
OR it could be that any remaining methanol in your biodiesel has evaporated out and what is causing your bio to gel is soap. This assumes your drywash towers didnt catch it all. To test this take some of your sample bio like 500ml and heat it it up above 150F to drive off the methanol (be careful methanol fumes are harmful/flammable) and let heat for about an hour to be safe. let it cool and sit for a couple hours. if it gels up there is soap.
I don't think water or growth is an issue, I don't leave anything outside it's all inside and temp controled and had only sit about a week before I sent to the drywash towers. The gel is in my raw bio before it is drywashed, currently don't see any gel in the finished bio that's been drywashed. I'm just afraid to use the finished bio since it shows glycerides, according to the Phlipp test. It passes the 27/3 test and it shows no soap with the soap test. I don't quite understand that though, I show no soap with the soap test but show heavy glycerides in the Phlipp test, I thought glycerides is what soap was??
I only bubble for about 6 hrs. could this be excess methanol and glycerides? If so what is the best way to salvage this stuff. Thanks for the test, I will try it tonight hopefully (may be Sat before I get to it) and report back. Would this show soap that the soap test doesn't?
If you acidified a small sample and it turned to liquid, soap would be the culprit..
Sounds like soap to me too. As the methanol is driven out of the BD the soap drops out of solution. This can take some time depending on how well you have removed the methanol. If you do as sinbad says and add a little bit of acid to the gel, it should liquify and then you will have a mixture of BD that was trapped in the soap and FFA's. If you weigh equal amounts of the liquified gel and the BD, they should be almost the same.
As far as using the BD as it is, it depends on what you drive. I drive a Dodge Cummins, so I wouldn't be concerned at all.
I agree, sounds like soap to me to.
The gel is common when using excess NAoH. Check that your titration solution is still accurate and try a base of 5 instead of 5.5 and see if your yield goes up and soap down.
In my opinion this is a waste of your time. Until you get all the methanol out there is nothing to filter. I would just demeth it and then let it settle for a day or as long as you can stand it then filter it or just draw off the top of your settling barrel into your towers.
Simple schematic for a pump and heater control with a high limit
Sensor for the biodiesel/glycerin layer
Thanks for all the ideas and help, after looking at it a little more I believe it is soap as well. Just for my own curiosity I took a sample of the bio/gel combo and reprocessed 500ml with 1/2g NaOH and 17ml of methanol. The reaction was complete no more glycerin, hence passed the 27/3 test, but it did turn to all gel. I have suspected my bubbling is in adequate to get most of the methanol out and consequently get all the soap out. In a 110 gal cone bottom tank I was using two wood bubble blocks attached to an aquarium pump. I started rewashing the bio and processed another batch last night so I plan on redoing my bubbler. I plan on making a ring of vinyl tubing with a cross member, drill holes all around in the tubing and attach two input lines, one on each side and place it about 6 inches off the bottom of the tank. Does that sound sufficient, any ideas or pics from air bubblers out there I would appreciate it.
Sorry about the confusion you are correct I misplaced the filtering in my process above, it is the last step after I bubble wash then pump to the drywash barrel.
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