[Stoves] Tar characterization

Bond, Tami C yark at illinois.edu
Sat Nov 12 15:54:12 CST 2016


I totally agree, Frank. We are working toward this. The trouble with TGA (I am good at bringing up troubles) is that the sample particles are small and that affects the heat-transfer rate in (faster), temperature profile (less variable), possibly product distribution.

May have more to say in a couple of years. :-)

Tami



On Nov 12, 2016, at 1:09 PM, Frank Shields <franke at cruzio.com<mailto:franke at cruzio.com>> wrote:

Hi Tami, Stovers,

This is great for someone interested in working on this.

We don’t need it to be over analyzed. As a stove heats up volatiles come off as a function of heat, particle size, air flow and time based on the makeup of the biomass. I don’t think there is a need to know the make-up (cellulose, lipids, oils, lignin etc) but may be helpful. Therefore we may only need the mapping of these volatiles as they come off.

Heating without oxygen will give the total volatiles that come off and travel to the secondary to ignite and provide heat at the point of cooking. That is one good measurement to get total. A TGA could do this like what Tom Reed did.

But we need more. Because the volatiles are what is used for secondary combustion we need to map their release as the fuel heats up. I am thinking a Standard Combustion Chamber (perhaps 15 cm dia X  30 cm long) with rings of separate heating elements along the inside from top to bottom and controlled air flow at top or bottom. This is a combustion chamber fitted with only primary air and the gases determined as they leave the chamber that would normally be used for the secondary. These gases are what we measure. Their rate and concentration. With this type of set up I think we could match fuels to different stoves. Flexible enough to simulate any stove type.

How to measure the gases I am not sure about. The helium surrogate could be used to monitor the rate specific gases come off per gram of fuel. But what we really need is the flammability of the gases. I am thinking of a stainless heating tube fitted with heating coil used to weld plastics. Oxygen introduced and combustion gases bled into the oxygen flow and temperature of the stainless tube monitored. Or better might be simply plot the CO2 released from the SS tube. It could all be very simple.

Regards

Frank

Frank Shields
Gabilan Laboratory
Keith Day Company Inc.
1091 Madison Lane
Salinas CA  93907
(831) 246-0417 cell
fshields at keithdaycompany.com<mailto:fshields at keithdaycompany.com>




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