Breaking an emulsion with salt. Where does the soap go?

[rumple]

Hi there. I've just finished making my first 200 litre batch of the year. It was a bit of a pain as the oil was really crappy stuff and it consumed a lot of KOH. I'd glycerol prewashed to try and dry it prior to brewing. In the end I got a really clear 10:90 pass. As it was late in the day I didn't do my normal water prewash which was a mistake.
I was experimenting with air bubbling through water for my first water wash of the batch of bio. During the process, the connection to the airstone came loose and the batch was subjected to big bubbles for an hour or so and it formed an emulsion.
I've used salt to break an emulsion I had some years ago and the water dropped really well. My question is does the soap come out with water or does it remain in the biodiesel? I think I'll go back to gentle water misting.

[dgs]

Hi there. I've just finished making my first 200 litre batch of the year. It was a bit of a pain as the oil was really crappy stuff and it consumed a lot of KOH. I'd glycerol prewashed to try and dry it prior to brewing. In the end I got a really clear 10:90 pass. As it was late in the day I didn't do my normal water prewash which was a mistake.
I was experimenting with air bubbling through water for my first water wash of the batch of bio. During the process, the connection to the airstone came loose and the batch was subjected to big bubbles for an hour or so and it formed an emulsion.
I've used salt to break an emulsion I had some years ago and the water dropped really well. My question is does the soap come out with water or does it remain in the biodiesel? I think I'll go back to gentle water misting.

Most of the soap will be in the water layer but some will remain in the bio so just be careful how you water wash the rest of the batch. generally the cut off point between 'will it or won't it' emulsify with more aggressive washing is about 500ppm soap. If you do a prewash method with water and glycerol approx 50/50 it usually leaves the bio at less than 250ppm soap. This means that you can then wash as aggressively(usually pump wash) as you want without fear of emulsification. There is no need for messing about with tiny bubbles or misting using the prewash method and leaving to settle for a couple of days before you w/wash.

[rumple]

Hi DGS. I was just curious to try bubbling on my first batch of the year but it'll be back to prewash on my next batch. After splitting the emulsion the water was really clear which made me ask about the soap. Thanks for the reply.