Has anyone any data, scientific or empirical on the amount of soap wood-chips can absorb (so as not to be effective anymore).
Let's say for each gram of dry wood, can the wood absorb 0.1 or 0.01 grams or.... even an order of magnitude would be useful info.
Alternatively, for a given volume of already soaked chips, how much BD with what original soap ppm have you put through them before used up?
Utah biodiesel might be able to help if you call them. You can find them on the internet.
There is no valid answer; too many variables. In any case, you should test every batch for residual soap after it's run through a 'dry wash' column.
look in appendix A
It's the only academic study i've found so far. Not sure it answers your questions though.
video of change time: http://www.youtube.com/watch?v=KfTrK0iNj28
more links at the bottom of this page:
Not scientific but real worlds experience (see interview in sig line). Two sets of 4 200L drums each had over 1/2 million liters through them and were still usable. Soap ppm were constantly measured to zero. High soap volume biodiesel would be put through a second time until zero PPM was reached.
** Biodiesel Glycerine Soap - The Guide
- on 5 continents helping people make & sell soap from the Biodiesel Glycerine.