Dry wood using vacuum pump?

Woodgas Science
#1

Hi there!

I think one of the biggest barriers to wood gasification is having a good dry fuel biomass. I was thinking of trying to dry the biomass in a vacuum (see http://www.instructables.com/id/Vacuum-Kiln-or-Atomic-Bomb-you-decide/) but wasn’t sure if in the vacuum the important gases needed for gasification would be released and sucked out of the pump as well?

Any thoughts?

Thanks,
Mike

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#2

Interesting concept. I could easily see the advantages for a lathe project I think time is our friend for the volume of wood we need for our trucks though. Thanks for posting.

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#3

Yes, it technically will work. If you’re in a huge rush for dry wood this will help speed things up.

The main drawback is that vacuum is a very expensive form of energy, and you will rarely find it for free in large quantities.

I much prefer sunlight and wind, or waste heat. An exhaust dryer should work very well for drying wood chips.

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#4

I agree with Chris totally. But from my perspective, lowering the pressure, is the same as increasing temperature. Water boils at 212 under normal atmospheric pressure. But you can boil water at room temperature by pulling enough vacuum. Water boils at 212 as I said, but the gasses driven off from wood occurs in the range up to 600 degrees. So to pull the volatile gases off, you would need much much more vacuum.TomC

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#5

its true, boiling point changed with pressure.

#6

True. The problem is that after about 1/2 of the water is removed by vacuum, the rest will turn to ice and not leave. The heat of vaporization to lose the water comes at the expense of the remaining water’s temperature.

Try this instead:

It’s way easier and less energy intensive.

Stephen

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