Ive seen them online for 30 bucks even less.

Some even come with inbuilt TDS meter which is a handy quantity to measure if you do dry washing. You can test the break thru levels, resin life etc etc.

Only thing is with ph meters u need buffer solutions and calibrations.. whatever works best for the individual i suppose

I have an EC meter and buffer for calibration, is that of any use in this hobby?
Jon

I would have no idea, Jon. But I'm sure someone will chime in who would know.

Ok, here's the next question. Suppose I do the soap test, and I find a high level of soaps? Is it possible to reprocess the batch, do a WBD, and further lower the soap content?

Remember that this last batch was made with recovered methanol of about 90-95% purity. This problem probably wouldn't have happened if I used fresh methanol in the first place.

The next batch this weekend will be made with fresh methanol.

I doubt you will lower the soap level by reprocessing. You could make additional soap. If you had good conversion, just filter the crap out of it and use it.

Another option would be to add a small amount of acid to it to convert some of the soap back to FFA's and burn the mix. I am not sure you want to do that though. However, it is an option.

Spence you are using woodchips right?

If Im mistaken and u water wash, leave the bubbler in over night again (water bubbler washing). When I bubble washed I did 2 static mists and draining, then a static mist with 24 hour bubbling. If there was still soaps i would just increase bubble time. Also Found once biodiesel is dried the tested soap content is lower. Again I would dry by draining all water after settling then bubble drying for 24 hours to get sparkling bio. If the bio doesnt clear up in 15 mins theres a good chance u still have soap.

If your using wood chips, try doing another pass thru ur chips. Keep flow rate nice and slow. Or let bio sit in the woodchips for x period of time. Reprocessing won't get rid of soaps, thats the job of the washing part of the production process. If you are continuely passing ur biodiesel thru ur woodchips and still cant get ur soap content low, you might have to go back to the drawing board with ur woodchip setup.

Now Im doing drywash, I demeth and let biodiesel just sit for 24 hours. In the MDPE tanks you can see quite a bit of soap which has fallin out. Maybe an inch or so?. My soap ppm after just settling is less than 500ppm and ready for the towers.

Another thing I use to do was filter my biodiesel thru a sock filter, this would also get rid of a bunch of soaps. Try this when ur biodiesel is cold. The sock filter can just be rinsed out with a hose and used over and over again for future batches.

Reece,

Yes I am not using water washing but using a gravity feed system of filtering the raw biodiesel through a 55 gallon drum of wood shavings/chips.

I still have to ascertain what the soap content is now, but can run the biodiesel thus generated once again through the SD (sawdust column) and then test. I have to wait until I get some bromophenol blue to test for soap content.

I did a small shake 'em up test last night, and the results weren't encouraging. I know it's far from a conclusive test, but the cloudiness of the water wasn't too good. It was translucent but not clear.

I'm thinking that water, either from the recovered methanol or the oil not being completely dried, has lead to this problem.

I'm going to try again this weekend by fully drying the oil to be used and then using pure methanol now that I have a fresh drum of alcohol. I will then fully implement all phases of GL's process minus the 5% wash and see what happens. GL's process is stated to eliminate the need for washing, I just need to be more patient and let the final product settle out.