[Gasification] Chip drying without pyrolysing; Biocoal manufacture.

Luke Gardner lgardner at wwest.net
Sat Jan 25 21:10:38 CST 2014


wet chips... wet chips... wet chips
getting them to be dry chips is a real hurdel
yes darius its like Goldie locks’ double edged sword (if you follow)
try to use heat, and they catch fire... big problem
strap that fire waiting to happen to a 100k$ truck with 50 gallons of diesel aboard.... real big problem.
it is of my mind that a motorized trommel is the way to go.  If the trommel is set with about a 15 degree down angle the chips will migrate from the feed end (upper) toward the output end (lower) as it revolves.
The motor running it could be geared way down, and put on a timer such that every hour it kicks on for a minute and makes one half revolution.
A long trommel would also give the opportunity create stages, such that the first stage could have finer screen, the bin below this section would fill with “fines” smaller than desired.
Then the next stage could be screened for the target chip size. with a bin below.
The output end of the trommel could fall into a bin of larger than desired chips, chunks, sticks.
My gasifier has not run in a few years because of a lack of dry chips, or shall I say the mess and time and energy required to dry chips.  I will have more into fuel prep than I will have into the entire gasifier/generator.
it is my belief that one needs to allow nature to remove the unwanted water, because if you try to force the issue not only does the whole system become net negative, but the risk of fire eventually becomes unmanageable.
Gotta flip the chip, and be cool about it.

Luke Gardner



From: darius_tamizi 
Sent: Saturday, January 25, 2014 4:57 PM
To: Discussion of biomass pyrolysis and gasification 
Cc: Discussion of biomass cooking stoves 
Subject: Re: [Gasification] Chip drying without pyrolysing; Biocoal manufacture.

Drying static rawwoodchip pile with heat is almost impossible.

With temp lower than 150C, water vapor condense before leaving the pile.

With temp higher than 150C, you will get fire from the drychip at the bottom


Terkirim dari Samsung Mobile



-------- Original message --------
From: Doug <Doug.Williams at orcon.net.nz> 
Date: 26/01/2014 03:12 (GMT+07:00) 
To: Discussion of biomass pyrolysis and gasification <gasification at lists.bioenergylists.org> 
Cc: Discussion of biomass cooking stoves <stoves at lists.bioenergylists.org> 
Subject: Re: [Gasification] Chip drying without pyrolysing; Biocoal manufacture. 



Hi Tom and Colleagues,

Having spent the first 9 years of my "trade "life in transport engineering, your idea is sound but difficult to put into practice. Chip trucks are tippers, so the exhaust would have to enter the box via a flexible hinge at the rear of the body. Not impossible, but difficult to organise as most exhausts exit vertically up the back of the cab. You would then need a body floor that is probably perforated, or for trials fitted with a piping system on top of the floor.

Having used exhausts a lot over the years into drum driers, but not closely controlled to 300C, but around 300C just the same, given enough time, the chip on the bottom starts to cook, and you see this at a point when steam and blue smoke comes out the top. This is much the same problem for any static pile, so introduces the need for chip movement. Rotational drying is a known technology, but in the circumstances that we might dry chips for gasification and whatever, I have often thought that our primary sources of heat is slightly different in it's acquisition to those of most commercially available dryers.

While we continue to seek easy solutions and simplicity of design, the answers to these questions remain complex for those charged with resolving the problems. The calculations may show what might be possible, but it doesn't tell you how it's achieved(:-)

Doug Williams,
Fluidyne.





On Fri, 24 Jan 2014 08:27:58 -0500
Tom Reed <tombreed2010 at gmail.com> wrote:

> 
> Here's a simple solution, and I hope someone will try it before I need to.  
> 
> If you are transporting the chips any distance by truck, 2/3 of the truck's fuel goes out the exhaust pipe as heat, enough to dry a load of chips the truck is carrying.  The temperature of the exhaust is closer to 600C as it leaves the engine, too hot for drying.  But if air is aspirated into a side stream of exhaust the ratio of exhaust heat to added air could be adjusted with a simple spring thermostat to 300 C (or other as required) to "cook or cool" the wet chips without overhearing them.  There is plenty of exhaust pressure available for the aspiration before the muffler, and the drying would muffle this side stream as well.

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