[Stoves] Clinker Formation - Oorja and forced air

[Paul Anderson]

All,

I like Tom's comments.    And I remind Otto and others that there is a 
major difference between the TLUD pyrolysis stage in an Oorja and the 
carbon-burning stage in the same stove that is operated after the 
Migratory Pyrolytic Front (MPF) has reached the bottom.   THAT is why 
the Oorja has the cast iron cup at the bottom, to protect the regular 
metal from the forge-heats of air blowing on hot char.   With the FORCED 
air onto that hot char, the cup glows red hot.   And with the forced air 
the fine particles can be elevated out of the cup and out of the stove, 
and into the room, as Otto has described.

Otto wrote:
> To avoid clinker formation, we just removed the char [from a TLUD 
> stove] , before it starts glowing, namely biochar.......problem solved?
I agree.   But point out that such a solution is equally possible if the 
TLUD has Force Air (FA).

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 5/18/2014 12:08 PM, Tom Miles wrote:
>
> Otto,
>
> The TLUD should be the perfect device for high ash fuels. Jock Gill 
> has burned a lot of grass pellets in TLUDS so that should be  good 
> indication. Paul W had burned bundles of grass as you, Otto, probably 
> have. Just as you have described the temperature in the carbon should 
> be well below sintering temperatures low until you reach the char 
> burning stage. At that point you will be oxidizing he carbon at well 
> above 1000C which will melt most ash and you will get clinkers.
>
> The fine carbon burnout will only be as efficient as the gas burning 
> portion of the TLUD even so it should be very good. I agree with Dean 
> that the carbon burnout in a forced draft stove might be an issue. On 
> the other hand you can have low velocities at the grate and higher 
> velocities above the grate burnout should be very good. The challenge 
> is doing that in stoves that operate at low power, poor air control, 
> and burns with very high excess air. It would be difficult to 
> recirculate flue gas in as small stove. Even then you need lower 
> oxygen in the recirculating gas than you can get in a stove.
>
> Tom
>
> *From:*Stoves [mailto:stoves-bounces at lists.bioenergylists.org] *On 
> Behalf Of *Crispin Pemberton-Pigott
> *Sent:* Sunday, May 18, 2014 2:48 AM
> *To:* stoves at lists.bioenergylists.org
> *Subject:* Re: [Stoves] Clinker Formation
>
> Otto that straw pellet test will be important because it may have all 
> its Cl and K in it so the melting temp will be lowered.
>
> If processed agri-wastes are to be an important fuel they will have to 
> be accommodated by the designer.
>
> Regards
>
> Crispin
>
> BBM 2B567C3
>
> *From: *Otto Formo
>
> *Sent: *Sunday, May 18, 2014 16:39
>
> *To: *Stoves Bioenergylist
>
> *Reply To: *Discussion of biomass cooking stoves
>
> *Subject: *Re: [Stoves] Clinker Formation
>
> Dean Still,
> According to Crispin and to our experience, the flames reaching the 
> cooler pot, instantly create char or black carbon - insufficient 
> combustion create more PM and black carbon........!?
>
> The fan driven Oorja, was tested here with woodpellets, four years ago.
> At full blast the "room" was soon covered in a thin layer of soot and ash.
> The cast iron combustion "chamber" was glowing instantly- around 1000 
> - 1100 C.
> What about ultra fine particles......??
>
> Natural Draft gasifiers, are the way forward................
>
> We will soon test the Peko Pe with staw pellets and see the effects of 
> clinker formation.
>
> Using Corn colbs  (agri-waste) as fuel, we noticed a temperature of 
> 450 - 550 C at the top of the flame and around 350 -400 C at the 
> pyrolysis front.
> At the end of the burn, when most gases are utillized and the char 
> starts glowing, we can raech the temperature arond 900 - 1000 C.
>
> To avoid clinker formation, we just removed the char , before it 
> starts glowing, namely biochar.......problem solved?
>
> Otto
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20140518/2331c711/attachment.html>