[Gasification] Getting both heat and char .....

[Paul Anderson]

Doug,

The AVUD method is ignited at the level of the "grate" (actually a pipe 
with holes on side and bottom, so the char can pass around the pipe, 
drop below the hot zone, and be extracted at regular intervals).  The 
heat rises and pyrolyzes the biomass above, and additional fuel is added 
regularly on top of the fuel pile.   That makes it a continuous 
process.   No need to stop.

The tarry gases exit and are combusted with turbulent air, coming from 
an air compressor.   The combustion is quite complete and clean.  This 
has similarities to the    Dasifier    made by Agua Das almost 20 years 
ago.    You should read these materials at my website:

http://www.drtlud.com/?s=dasifier that link leads to

http://www.drtlud.com/wp-content/uploads/2015/01/Dasifier-Foundry-Gasifier.pdf 


and see a 2012 video with Das himself melting metal with woodgas at:

https://www.youtube.com/watch?v=t08tj4NWUQY

Many years ago Das was one of my teachers and mentors, and a good friend 
of Tom Reed.

Paul

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
Email:  psanders at ilstu.edu
Skype:   paultlud    Phone: +1-309-452-7072
Website:  www.drtlud.com

On 1/5/2017 8:19 PM, Doug wrote:
> Hi Paul,
>
> There is a difference in how pyrolysis (smoke gas ) can evolve, and 
> from what I see of the AVUD design, it appears that it still follows 
> the top lit philosophy. Maybe I scan read too fast, but neither write 
> ups stated how the bed is ignited. My understanding from the drawing, 
> is that the bed is ignited at the top, and they burn down towards the 
> grate which has air aspirated or blows at low pressure in from the 
> bottom. This changes both how the gas evolves and it's hydrocarbon 
> content, depending on they type of fuel available. While it can be 
> considered pyrolysis gas, it certainly has to be a higher quality than 
> the chocking yellow smoke gas that most charcoal makers see full of 
> hydrocarbons. The give away is that pyrolysis gas burns red/yellow 
> with air, and better quality gas burns blue. What is considered a good 
> color for your stoves?
>
> When the fire is located at the grate  of an updraft and interfacing 
> the incoming air, high temperature oxidation forms at the bottom of 
> the bed, and depending on the air pressure, can build an oxidation bed 
> up to 4" deep, driving  incandescent CO2 up through the incoming raw 
> fuel. It is one might say, almost instant charring. Fine chars and 
> carbon blacks are carried out of these types of air flows. Our 
> charmaker has a controllable blower type fan capable of 15" W.G. max. 
> and this is able to push the gas through a 48" vertical bed loaded 
> from the top.
>
> Hope that clarifies how the carbon escapes.
>
> Doug W.
>
>
> On 06/01/17 11:26, Paul Anderson wrote:
>>
>> I agree that what Rolf is seeking is not a TLUD.
>>
>> You wrote:
>>> May be the ash from the carbon dust will settle in the tunnel 
>>> depending on combustion gas velocity. Usually, a correctly sized 
>>> flue stack is required to assist with removing the exhaust gas, and 
>>> this is where ash dust can become an emission.
>> I have not experienced carbon dust or ash from carbon dust or ash 
>> dust with the AVUD design.
>>
>> Again, thank you for your strong support for gasification of biomass.
>>
>> Paul
>
>
> _______________________________________________
> Gasification mailing list
>
> to Send a Message to the list, use the email address
> Gasification at bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
> http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org 
>
>
> for more Gasifiers,  News and Information see our web site:
> http://gasifiers.bioenergylists.org/

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/gasification_lists.bioenergylists.org/attachments/20170105/caed1d67/attachment.html>