Biopowered - vegetable oil and biodiesel forum

Biodiesel => Chemistry and process => Topic started by: Head Womble on March 08, 2013, 04:59:24 PM

Title: 7% water prewash before water washing
Post by: Head Womble on March 08, 2013, 04:59:24 PM
After reading Nigelb's post about soap testing
http://www.biopowered.co.uk/forum/index.php/topic,1036.0/topicseen.html
I'm interested in finding out who else does a 7% water prewash before water washing,
this is a common practice for demeth and settle, but how many of us do it before water washing ?
Title: Re: 7% water prewash before water washing
Post by: Tony on March 08, 2013, 05:04:43 PM
Maybe it's not as common for demeth and settle as we think.  I certainly don't do it and haven't for years.
Title: Re: 7% water prewash before water washing
Post by: Head Womble on March 08, 2013, 05:28:10 PM
Maybe it's not as common for demeth and settle as we think.  I certainly don't do it and haven't for years.

I know that Tony, but you're "special" aren't you.
Title: Re: 7% water prewash before water washing
Post by: 1958steveflying on March 08, 2013, 07:18:28 PM
I demeth and settle but never do a 7% water prewash as I use the glyc for oil pre treatment, which includes a partial reaction which I understand it wont do with water in it.
Title: Re: 7% water prewash before water washing
Post by: Bill on March 08, 2013, 08:20:38 PM
I have tried 7% prewash but found the glylc was less effective at reducing the titration value of the oil after a glyc wash. I prefer to get the oil in the best condition prior to conversion. Therefore less chance of forming soaps in the first place.
Title: Re: 7% water prewash before water washing
Post by: Tony on March 08, 2013, 08:42:20 PM
I know that Tony, but you're "special" aren't you.

That's what my mum used to say too  ::)
Title: Re: 7% water prewash before water washing
Post by: Soft top on March 09, 2013, 08:32:00 PM

I do the pre wash before water washing. I then mist wash and have found that I only have to wash 3 times to remove most of the soaps if I have done the prewash first.
I recently tested at each stage and after washing I had only 54ppm soap.