[Stoves] Clinker Formation

Sun May 18 13:04:56 CDT 2014

Hi All,

There were clinkers in the Oorja when burning the grass pellets made for
the stove but they were not difficult to remove.

The high ash fuels in my limited experience are not easy to burn in a
natural draft TLUD because the ash extinguishes the fire. When burning
dung, for example, the stove needs a grate with large spaces and has to be
shaken for the fire to continue.

All Best,

Dean

On Sun, May 18, 2014 at 10:08 AM, Tom Miles <tmiles at trmiles.com> 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
>
> Date: Sat, 17 May 2014 17:25:27 -0700
> From: deankstill at gmail.com
> To: stoves at lists.bioenergylists.org
> Subject: Re: [Stoves] Clinker Formation
>
> Hi Tom,
>
>
>
> Does cooling the burn reduce black carbon? Are ultra fine particles more
> of a problem in forced air stoves?
>
>
>
> Best,
>
>
>
> Dean
>
>
>
> On Sat, May 17, 2014 at 3:36 PM, Tom Miles Easystreet <tmiles at trmiles.com>
> wrote:
>
> Think of flue gas recirculation as a way of trimming excess air at the
> same burn rate while cooling the flame. The Kob boiler is nicely rigged for
> it.
>
>
>
> Tom
>
>
> T R Miles Technical Consultants Inc.
>
> tmiles at trmiles.com
>
> Sent from mobile.
>
>
> On May 17, 2014, at 9:00 AM, Crispin Pemberton-Pigott <
> crispinpigott at outlook.com> wrote:
>
> How is it used to lower the temperature? By interfering with the O2 supply
> thus reducing the burn rate? Or the efficiency of combustion?
>
>
>
> Thanks
>
> Crispin
>
>  On Fri, 16 May 2014 07:59:49 -0700,"Tom Miles" <tmiles at trmiles.com>
> wrote:
>
> >
> >Stages combustion in a pellet burner can be a challenge. Most pellet
> burners are designed to burn the fuel and air mixture at the highest
> temperature which is usually in the range of 1000C- 1100C range which will
> melt most dirty fuels.
>
>
> Does anyone use exhaust gas re circulation to lower the bed
> temperature burning pellets?
>
> We had this on the Kob boilers which burned shredded furniture waste,
> but generally did not need it with G30 woodchip on the adjacent
> boiler.
>
> AJH
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
>
> for more Biomass Cooking Stoves,  News and Information see our web site:
> http://stoves.bioenergylists.org/
>
>
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
>
> for more Biomass Cooking Stoves,  News and Information see our web site:
> http://stoves.bioenergylists.org/
>
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
>
> for more Biomass Cooking Stoves,  News and Information see our web site:
> http://stoves.bioenergylists.org/
>
>
>
>
> _______________________________________________ Stoves mailing list to
> Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org to UNSUBSCRIBE or Change your List
> Settings use the web page
> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.orgfor more Biomass Cooking Stoves, News and Information see our web site:
> http://stoves.bioenergylists.org/
>
> _______________________________________________
> Stoves mailing list
>
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
>
> for more Biomass Cooking Stoves,  News and Information see our web site:
> http://stoves.bioenergylists.org/
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20140518/17c1fe7d/attachment.html>