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Centrifuges Really Work

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EdDee:
Hey guys,

My less than 1c's worth....

I cold fuge my oils, granted they're WMO, slightly thinned with waste mineral turps, mainly fuge'ing to remove solids and water. The turps originates from a chainsaw wash bay, full of sand, metal filings, water, dust and goodness knows what. The WMO is from various backyard sources, mystery oil, gearbox, sump, diff, grease, dead kittens and puppies included.... This oil goes mostly to my burners these days, but I wouldn't hesitate to run it through the listers in an emergency...

Home made Hi-G fuge, single pass, low flow rate (its a tiny little fuge with the cup being less than 100dia and 100high...

The oils, on exit, are cold, the housing of the fuge barely warm... The air pressure in the fuge is slightly below atmospheric... During spinning of very wet oils and waterlogged diesel, I set the feed flow rate to just borderline water vapour expulsion.... This is not hot steam, but cold mist that emanates - I have some theories as to why, but no substantiated proof as such. At this flow rate, the spun product leaves the unit with little to no water content. But, it is a slow process... My targets for fuel production are but 3 to 4times my consumption... Meaning that I have a scaled down micro version that outputs about 10-20L per hour, depending on contaminant levels... (This is sludge we're talking about here...)

On polishing diesel or other liquids without heavy contamination, I could up the throughput substantially, as I have done in the past.... (Less than a 1% water/contamination level by volume)... The output product is significantly cleaner than store bought fresh diesel when viewed under a microscope.

As to energy usage - 100 to 150W, a little more when the scavenge pump kicks in, easily supplied by a small inverter/toy solar setup during daytime, load on a genset for night operation during emergency is more than tolerable as I use a VFD to control the fuge with soft start/stop... So, after a whole lot of rambling, NO, its not "heated steam" but a cold mist, keep the g's high enough and the flow within the limits of the cup, and you don't need to heat the input product either..... Well, not me, anyway.... But then I do everything arse backwards.... LOL....

Cheerz
Ed

veggie:
 
--- Quote ---
In this scenario, the fuge is not eliminating the water, the added heat, presumably near the boiling point of water is. That is a lot of energy for even a 200L batch and if you are heating it electrically, a fairly slow and expensive process.

On a 20oC day at around 60% Humidity, I can dry and filter a 200L batch of oil in 30 min with well under .5 Kwh of power used with the bubbling/ pumping method.

--- End quote ---

Yes, the fuge is eliminating water. When you spin warm oil at 5000 g's at a very low flow rate (high retention time) the portion with the heavier specific gravity (water) is separated and pinned against the back ball of the centrifuge drum along with fats and particles. The clean oil continues on.

Define slow and expensive. My system draws 2.5 kw when running. For an 8 hour batch that's 20kw worth of power.
At $0.08 per kwh that amounts to $1.60 per batch of 80 gallons (300 liters).

veggie:

--- Quote from: glort on November 19, 2019, 03:27:16 PM ---
20Kwh, 8 hours, 300L??  Yep, nothing has changed.  Still energy intensive, slow and expensive.
Spose as long as we are happy with what we prefer, that's all that matters.

--- End quote ---

Hey Glort,
I suppose if you consider $0.0053 per liter expensive then you would be correct.
($1.60 per 300 liters)

You tried various methods and prefer settling. I tried various methods and settled on Spinning.
Everyone has their own set of circumstances and constraints. Mine are very limited space and limited batch sizes.
As long as it works, it really does not matter what system a person uses.

cheers mate  ;)

veggie:
Yes. The price is steep for the centrifuge setup. I have a few buddies who bought them.
In my case I just bought the machined/balanced bowl and built the rest from scrounged metal.

I wonder how much longer WVO will be avialable in my area. 2 new companies have opened which set up free waste removal for restaurants. There we already several in operation. They process the VO on a large scale. Cleaning it for some use. I don't think it's for biodiesel because it's not economically feasible here. One by one restaurants are accepting their collection bin for waste oil dumping. Small VO collectors are running out of supply.
These companies even pick up from private users. One of my friends had too much to process. He called them and they drove over with a vacuum truck and sucked WVO from two 1000 ltr IBC totes that he had.

Since the drop in Biodiesel interest there has not been much competition to get WVO. But with these new commercial processors, the remaining few home brewers are having trouble getting feedstock.

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