[Stoves] Sequestering carbon -

Wed May 6 17:19:47 CDT 2015

Thanks Crispin, many good ideas.

when I began the trials, I mixed a small quantity of clay with the powder charcoal and pressed it in a makeshift press using a hydraulic car jack which gives me 3 t at the most. Seems to be a lot, but not if you want to make 50 mm puks!

It got better when I reduced to 30 mm. But still, many of them did not like the initial handling after pressing or they sticked to the piston...
Things got much better when I mixed clay + cow dung. But that's not a good idea for bbq coal.
As I said before, straw fines helped a bit to bind the coal dust. I am still trying to get the right recipe.

I have tried to mix the clay as powder and moisten together, it works as long as there are fibers present!
Another way is to dissolve the clay entirely into a very thin slurry and give it into the mixing vessel.
It also works, but you have to take care not to form lumps.
The advantage is that this way makes the dosification in a future continuous system easier.
The idea is to spray it onto the coal passing on a conveyor belt instead of difficult batch processes.

But I still have to try this.

Sorry Sir, no green bananas available here! 

best regards

Rolf

On Wed, 6 May 2015 16:32:19 -0400
Crispin Pemberton-Pigott <crispinpigott at outlook.com> wrote:

> Dear Rolf
> 
> How about making the clay mix weaker and weaker until it lights well, then
> see how strong it is.
> 
> Then if it is too weak, go back a bit and try to light it.  If it lights OK,
> add a little more. This idea is to find out how much you have to add before
> the ignition is an unpleasant experience.
> 
> If it turns out it is not possible to get a strong enough mix using clay
> only, try adding something as well, such as waste green bananas, maybe
> cooked, maybe mushed up.
> 
> An alternative is to add a coating around the outside only that lights
> easily. 
> 
> And lastly, there is in a source of clay some very hard pieces (really
> small) that act like sand but are actually clay. You want that materials
> liquefied.  The solution is to soak them for a while before mixing the clay.
> You might even cook it - ask experts. When the clay is put into a mixer, for
> example, it may have to sit for a long time to get water into the very
> compressed, dried small pieces. If the clay is completely liquefied before
> mixing, what you are doing already may work much better with less clay and
> still be strong in the end, assuming that some of the material isn't really
> helping you, but could.
> 
> Clay is often mixed in a pug mill and then stored for a long time
> specifically to deal with this issue. Months. It is kept covered in plastic.
> Later it is put through again to spread the ingredients around the whole
> body (because clay is not necessarily homogeneous).
> 
> There was a guy making strong thin panels using a mixer and he found that
> rust running the machine a lot longer made the panels stronger with no
> change in the mix at all - just more time being spread around. 
> 
> I am very interested to hear of anything that works better. I know of a
> group in South Africa that was making coal-dung briquettes and coal-clay
> ones too, with about 25% clay. The holey coal briquettes made in Ulaanbaatar
> were 1/3 clay and they used a special short holey ignition briquette to
> light the first one. It is a TLUD stove with two or three (two models)
> columns of briquettes in a single combustion chamber. It took a long time to
> burn down about two feet.  Very low PM.
> 
> Regards
> Crispin
> 
> 
> thanks to crispin and all,
> 
> yes, i have tried clay before and IT WORKS FINE BUT THESE BRIQUETTES ARE
> REALLY HARD TO LIGHT!
> 
> I found it takes a well lit fire below or around them to get to the point
> where the clay does not absorb all the energy.
> Once burning, they work well but they give a lot of ash, true.
> 
> I live on an island in the Mediterranean, very touristic and with a high
> demand for good bbq charcoal. 
> So coal is out, not being available anyway. 
> Pity the clay as a binder is not very practical, either. It is cheap and
> works well as such.
> 
> I have tried ground,soaked and fermented straw. Not much good unless in high
> quantities but than it gives smoke.
> 
> Must try hay, someone said it works far better.
> 
> More to come!
> 
> Rolf 
> 
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