Trying to dry biodiesel at ambient temperature.

[dgs]

This is an attempt to dry my bio at ambient temps to compliment processing at ambient together with Julians idea of using short bursts of the pump.

In other words so the electricity usage is minimal.

It should be noted that 'ambient' at the moment is exceptionally high.

After water washing the last batch I left the bio in the wash tank for a couple of hours to 'drip dry' so any excess of suspended water would fall.

20 litres of this wet bio was transferred to a 20 litre cubie and the water content tested at 1530ppm. I inserted the bubbler ex the turbo dryer. This was pulling in air (360LPH) via the container of silica gel. I left it for 7 hours. Temp of bio was 22degs at the start rising to 24degs.

Another water test gave 1015ppm and a visual on the bio was that it was not quite clear (nearly clear but not quite) seems that the old assumption of dissolved water becoming suspended at around 1000ppm is correct.

It is drying again today after changing the silica gel. I will leave it for another 7 hours or so then test for water again.

[Julian]

Don't forget to factor in ambient humidity.  Currently here it's 30%.  Forecast predicts rain over the weekend after which the humidity should rise to 66%.


Interesting ... your drip dry comment.  The batch on which I'm going to try the glycerine drying, I have sitting, washed in the processor and I've been draining water from it each day.  Seems that water continues to drop for some time as I've been getting around 100ml/day for the last few days … it would take several hours heating and distilling to get that much out.

[dgs]

With the air passing through the silica I think deviations due to RH will be at a minimum.

Julian, have you ever bubbled your wet bio, not to dry it but the action of the bubbles seems to release a lot of the suspended water.

The Sander air diffuser puts out many more bubbles than a conventional stone. I've used one for years and I'm sure it helps.

The one at £2.99 is the one I use.

https://www.ebay.co.uk/itm/Sander-Wooden-Air-Stone-Diffuser-Marine-Aquarium-FINE-AIR-BUBBLES-Wood-Fish-Tank/292524922944?hash=item441bd81840:m:myT_LQ8J2h0s4WdJwGvqogA

[Julian]

I used to until the air pump gave up the ghost.  I used plastic or sintered brass air silencers from pneumatic cylinders.  They seemed to work well as far as producing fine bubbles was concerned but I only ever assumed drying took place … never did ant tests to quantify it.

If you recon the agitation of the bubbles makes water drop, I wonder if an ultrasonic transducer would have a similar effect?  Got it somewhere in the back of my mind that Nigeb has an ultrasonic cleaner … Nige?

[dgs]

I left the bubbler on 8 hours yesterday. Starting temp 22degs end temp 27degs. Water content now 680ppm. Fuel is now clear and bright.

It's on again today.

[nigelb]

The ultra sonic cleaner I had was borrowed from KH. I used it to clean the carb on my kit car. Keith has back now.

[Julian]

I thought it was something like that I read … just got it bottom about face.

Keith ...

[dgs]

After the last 8 hours drying the water content has ended up at 550ppm, so I suppose it was a partial sucess.

I'm sure, however it wouldn't work in winter at 10degs and a full 200 litre tank. Maybe holding it at about 40degs for longer may work, it depends if the electric usage would be less.