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Woodworks

Any new small charcoal retorts out there?

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Great to hear you are getting temperatures more under control. Are you finding that you can use less wood for the firebox now?

 

Maybe you won't have any sagging issues if you can keep the temperature at or below 500deg c?.... or maybe use some thicker more heat resistant material for the stainless angle, although 600deg C is probably much too hot if it's gonna stand up to the heat over time.

 

cheers, steve

 

Yes used about 1:8 fuel to charge. When charge was removed shut everything down and some of the original fuel that was left is now charcoal :biggrin:

 

Openspaceman

When referring to yields was that by volume or weight?

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I try not to go above 550 degrees. Normally cap off at 520.

 

My 3rd burn when to 570 degrees and I just vented and lit the wood gasses to bring the temp back down to just below 500 degrees. Then left it to carry on cooking.

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I try not to go above 550 degrees. Normally cap off at 520.

 

My 3rd burn when to 570 degrees and I just vented and lit the wood gasses to bring the temp back down to just below 500 degrees. Then left it to carry on cooking.

 

Great thanks

 

Where does it vent from presuming the firebox?

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Going to do another burn later today or tomorrow. Baring in mind I am trying to develop this as a product what wood size,type and moisture content should I use for the charge? Only used very dry branch loggings to date and it worked well but a bit niche.

Edited by Woodworks

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So from the point of view of basic BBQ charcoal the lower temps produce a higher yield.

 

 

Yes but that yield consists of some fixed carbon and some volatile matter, tars etc. As the temperature increases the volatiles are driven off and the fixed carbon increases as a proportion of the now smaller mass. So I am referring to yield as mass as a percentage of the original oven dry mass of the charge. The fixed carbon yield will be variable with species.The volatiles make the charcoal easier to light but they burn with a flame, or if the flame doesn't burn out they smoke a blue colour from the sol of PICs.

 

A large number of people in other countries still cook with charcoal in urban settings and this charcoal would be unacceptable to them as it burns with too much smoke and too quickly. Often their charcoal is made with denser species which makes for a harder slow burning charcoal which burns with no smoke or flame (and produces a fair amount of CO). I know of an Australian family that were used to cooking on the patio at home and tried to cook their Xmas turkey here using lumpwood charcoal, it smoked out the house even though it was on a covered patio.

 

 

Are there any advantages to a smaller yield with more fixed carbon? :

 

There would have been in the past, for industrial uses such as gunpowder making . In respect of biochar the fixed carbon will be recalcitrant whereas the tars will gradually be respired by bugs back to CO2 and water so on a long time-scale the carbon sequestration will dwindle to the fixed carbon content.

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Yes but that yield consists of some fixed carbon and some volatile matter, tars etc. As the temperature increases the volatiles are driven off and the fixed carbon increases as a proportion of the now smaller mass. So I am referring to yield as mass as a percentage of the original oven dry mass of the charge. The fixed carbon yield will be variable with species.The volatiles make the charcoal easier to light but they burn with a flame, or if the flame doesn't burn out they smoke a blue colour from the sol of PICs.

 

A large number of people in other countries still cook with charcoal in urban settings and this charcoal would be unacceptable to them as it burns with too much smoke and too quickly. Often their charcoal is made with denser species which makes for a harder slow burning charcoal which burns with no smoke or flame (and produces a fair amount of CO). I know of an Australian family that were used to cooking on the patio at home and tried to cook their Xmas turkey here using lumpwood charcoal, it smoked out the house even though it was on a covered patio.

 

There would have been in the past, for industrial uses such as gunpowder making . In respect of biochar the fixed carbon will be recalcitrant whereas the tars will gradually be respired by bugs back to CO2 and water so on a long time-scale the carbon sequestration will dwindle to the fixed carbon content.

 

Thanks again

 

Guess all my burns have been on the hot side as you don't get any flame or smoke with our charcoal.

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Thanks again

 

Guess all my burns have been on the hot side as you don't get any flame or smoke with our charcoal.

 

Once you get above 550C there's not much change as you get hotter, just the residual Hydrogen and oxygen elements are driven off with some carbon as higher tars., the biggest change is in the 330-440 region.

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Once you get above 550C there's not much change as you get hotter, just the residual Hydrogen and oxygen elements are driven off with some carbon as higher tars., the biggest change is in the 330-440 region.

 

Great :001_smile:

 

So other than damage to the retort there is not much to worry about with the higher temperature burns.

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So other than damage to the retort there is not much to worry about with the higher temperature burns.

 

Not that I can think of, plus the reduced yield.

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