Charcoal and Wood Vinegar Reactors

Author: 
Tom Miles

Charcoal and Wood Vinegar Reactors
Robert Flanagan, SAFFE, Huangzhou, China, July 31, 2007
[img_assist|nid=469|title=Full of Bamboo|desc=|link=node|align=left|width=400|height=533]

Attached are a few photos of a 1.5T/8hr charcoal+vinegar reactor we have here in China. The yield is typically around 20-25% charcoal depending on how much air is introduced through out the reaction. This is a typical yield and run time for pyrolysis, gasification is a faster cleaner way to make charcoal provided your feedstock is suitable and the moisture content is below 20%. To take a look at charcoal production on a small scale check out
http://www.youtube.com/watch?v=Wubjh8_b4Xg

Regarding vinegar (liquid smoke) I thought I'd give you some info on how it's produced here. I've attached a few photos of two charcoal/vinegar reactors.
[img_assist|nid=465|title=Paddle Reactor|desc=|link=node|align=left|width=400|height=300]
The paddle reactor can heat the biomass via external heat provided by lighting a fire below the sealed upper chamber. Then the biomass is constantly turned to get a uniformed temperature. The key to high quality vinegar production is to take the biomass up to just below it go's exothermic (For bamboo that is 285C) and hold it until all the vinegar is collected. Jeff at this point you could always feed the hot biomass into your gasifier. This is the same reactor I used to make the 50Kg's of research charcoal that I sent to ten university's last year.
[img_assist|nid=466|title=Linann Charcoal Reactor|desc=|link=node|align=left|width=400|height=300]

[img_assist|nid=464|title=1.5 T Batch Reactor|desc=|link=node|align=left|width=400|height=300]
The other reactor is a 1.5T (Feed) charcoal reactor that we've been working on. We just borrowed one of the condensers from a paddle reactor at this point. We produce about 400Kg of vinegar for each 1.5T input as our feedstock is quite dry (around 35% moisture content), so you don't need a lot of biomass to produce all you need of vinegar. The vinegar is left in the sun for about four weeks to allow the tar to separate and settle to the bottom.
[img_assist|nid=467|title=Vinegar Condenser|desc=|link=node|align=left|width=400|height=533]

The major difference between charcoal produced by pyrolysis and gasification is as follows. When you take the biomass into it's exothermic range with pyrolysis and limited oxygen the exothermic curve should pan out about 400C. With downdraft or TLUD gasification you pass primary air through the biomass to a hot carbon layer you flaming pyrolysis will never be lower than 600C, so your exothermic range just jumped from 285 to 600C. This is a very clean way to make charcoal from biomass with a low moisture content.

Regards,
Rob.
[img_assist|nid=463|title=Charcoal Product|desc=|link=node|align=left|width=400|height=533]