[Stoves] Lots of smoke after a few minutes of clean burning

[Mangolazi]

Hi Paul, 

I went back to basics and made a peach can gasifier, similar to this: http://sectionhiker.com/a-batch-loaded-inverted-down-draft-gassifier-stove-by-dave-sailer/

It looks like a simplified Pekope design with straight vertical airflow. I used twigs and got about 20 minutes burn time with very little smoke. Using crushed and dried peanut shells, I got about 10 minutes and there wasn't much char left. 

The nice thing about this small unit is that I could see all the processes going on without burning my eyebrows off, as with a paint can gasifier. Smoke generated from pyrolysis deep inside the can burns at the top. I saw flame jets at the secondary holes, as incoming air mixed and ignited with the wood gas. 

Overall it's a stove that's perfect for camping and a good educational intro to the field. I would add a concentrator lid for cleaner burning and longer run time. I would also enlarge the secondary air holes. 

Anyone used peanut or walnut shells in larger gasifiers? 


On May 8, 2016 11:58:35 PM GMT+08:00, Paul Anderson <psanders at ilstu.edu> wrote:
>Mango,
>
>1.   During pyrolysis inTLUD stoves, the air ratio is about 1 primary 
>and 4 or even 5 secondary.
>
>2.  Flames a meter higher than the top of the chimney!!!!!!   NOT 
>desirable!!  Indicates that something is seriously wrong.
>
>Did you base your construction on some design or model you saw
>somewhere?
>
>Have you used SMALL TLUDs?   With success?   Attain success with what 
>has been successful for others, and only then start making changes.
>
>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 5/8/2016 1:34 AM, Mangolazi wrote:
>> Hi Paul and Julien,
>>
>> Thank you for your replies. I set the mailing list to digest mode so
>I couldn't reply to your messages. It's been a while since I've used a
>mailing list.
>>
>> I used dried grass as tinder, with a few drops of hot candle wax as
>accelerant. Maybe flaming embers could have fallen downwards. But I
>checked the can contents after the smoke started and the bottom twigs
>weren't burnt, so I doubt it was a bottom fire that caused the smoke.
>>
>> What's curious is that I first had a clean burn with a meter-high
>flame coming out of the chimney. Then the flame dropped until it was
>barely out of the chimney and the smoke started. There's already a huge
>hole at the bottom for primary air; maybe that's too much. I've heard
>of a 2:1 secondary:primary air ratio for a clean burn.
>>
>> I'll try packing twigs in tighter with thicker ones at the bottom.
>I'll also reduce primary air and increase the air gap between the can
>and concentrator lid for more secondary air.
>>
>> I'm traveling around Southeast Asia at the moment. I see huge
>opportunities for small gasifiers but turning this into viable local
>ventures is always an issue, especially when LPG is cheap and easily
>available.
>>
>> Just curious, have TLUD stoves been tested at high altitude, say
>4000-5000 m?
>>
>> Thanks again!
>>
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