quote:

Originally posted by GrahamLaming:
Hi folks

This method should allow you to use less (possibly nil - edit 13 June 06) water in washing, and seems to make washing less prone to emulsions, as it allows you to scoop off much of the soap before the wash stage. Introduces no extra chemicals or materials. (I run a 5% prewash in the processor).

Must be done in a well ventilated area.

1. Empty your freshly reacted, raw BD into your wash tank, but DO NOT add water yet. Also 1/2 fill a Clear plastic bottle with some of this brew to compare with the end result.

3. Lower an air bubbler into the BD. I had my bubbler in the centre of the tank, like this...





4. Bubble air thru the BD for 24 hours. This does several useful things...

1. It helps evaporate and thus eliminate methanol.
2. The reduced methanol concentration reduces the amount of soap the BD can hold.
3. The liberated soap picks up air bubbles and floats to the surface as a thick scum.

[ Comment added 18 June 2006: Much of the soap also drops to the bottom of the tank. I'd suggest if you want to do a water wash after this process, do it in a separate tank, to avoid dissolving the settled soap in your wash water ]

So you end with with separated soap...




And now you can easily scoop off the soap with a sieve ...




Keep going until your soap scum recovery level reduces to negligible amounts.

Take another plastic drink bottle and 1/2 fill it with this soap-reduced BD.

Now do a gentle wash test on your 2 samples and you'll see the bubble processed BD has much better wash handling properties and of course less soap.

I bubbled at 50 degrees C in the beginning, straight out of the reactor tank, and let it cool down naturally to around 15 degrees C. A warmed tank would probably be better, maintaining a higher methanol evap. rate.

A recirculating pump thru a filter may further improve soap yield after the bulk has been removed manually. No idea what filter size would be best, but I guess it would need to be a bag filter to have enough capacity for the soap. At least bag filters are easy to wash out.

You can then wash your soap-reduced batch, with much reduced risk of emulsification and less water usage.

[ Comment added 18 June 2006: Much of the soap also drops to the bottom of the tank. I'd suggest if you want to do a water wash after this process, do it in a separate tank, to avoid dissolving the settled soap in your wash water ]