Andrew,
Thank you for your calculations that are strongly supportive of what I
wrote about TLUD charcoal.
Now we all need to put the facts into good use as we make constructive
efforts to utilize this distinctive char-making feature of TLUD stoves.
Paul
Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
Email: psanders@ilstu.edu
Skype: paultlud Phone: +1-309-452-7072
Website: www.drtlud.com
On 9/21/2017 1:54 PM, Andrew Heggie wrote:
> On 21 September 2017 at 18:17, Paul Anderson <psanders@ilstu.edu> wrote:
>> 1. Pyrolysis is around the 550 to 650 C range (unless burning very hot with
>> much forced air)
>> 2. The char yield is about 20% of the dry weight of the biomass fuel
>> (mainly think of wood).
>> 3. That char contains about 30% (NOT 50%) of the ENERGY of the biomass.
> Paul I have had a look at some of the early work on charcoal, I see
> graph by Pohl 1970 that show charcoal heated to 600C being composed
> 90% fixed carbon, now if you ignore the other 10% that contains carbon
> hydrogen oxygen and ash and you still have 20% of the original dry
> weight then you have 18% of the original dry weight as carbon. So if
> you start with dry hardwood at the 18.6MJ/kg Tom Reed allowed for it
> and most woody biomass and end up with 0.18 carbon at 33MJ/kg so about
> 32% in the fixed carbon plus a contribution from the 8% of tars etc.
> less the 2-3% ash (more ash from leaves buds straw etc.) So I suspect
> you are more right to be at the lower end than the 50% I gave which is
> what I remember from charcoal made at lower temperatures for sale in
> barbecues.
>
>
>> If writers wish to continue to say 50% of the ENERGY remains in TLUD-type
>> charcoal, then let’s resolve that here and now. Otherwise there can be no
>> true discussion about the value of the TLUD char.
> Agreed, let’s see what figures others have.
>
> Andrew