Learn How To Test Biodiesel For Soap Content | Springboard Biodiesel

[redblue18700]

When I add the bromoblue drops, my acetone or isopropanol turn yellow to begin with. I add my biodiesel and it stays turned yellow.

if i add only a tiny amount of naoh solution it turns blue so i know the indicator is accurate.

[UtahBiodiesel]

@redblue18700 It means your alcohol is acidic. I'd recommend getting new Isopropyl Alcohol.

[greengineers]

After the conversion is shown, the ASTM limit for NaOH is shown to be <41ppm, and for KOH, <66ppm. However, in the review, these numbers are reversed. What are the correct values?

[UtahBiodiesel]

@greengineers

For Potassium Hydroxide reacted Biodiesel - No more than 66 PPM

For Sodium Hydroxide reacted Biodiesel - No more than 41 PPM

[fuze59]

If you have residual catalyst in your biodiesel won't this effect the amount of HCL that you will need to add?

Therefore you're initially neutralizing catalyst not the soaps.

[graydonblair]

It's possible that that can occur but the catalyst will normally fall out in the glycerin. Be sure to stop by biodieseldiscussion [dot] com and visit the dry washing section as they've been discussing soap testing at great length including this potential issue. Great question by the way!