[Stoves] Increasing ND-TLUD riser height accelerates gasification and increases bed temperature

Ronal W. Larson rongretlarson at comcast.net
Mon Dec 15 22:30:55 CST 2014


Julien cc list

	1.  I found your “vignette” most interesting.  I am not aware of anyone else who has provided this detail on what is happening within the char-making bed.  Not yet a stove design, but potentially useful in several ways.  This below is to ask for more detail on a few parts of your data.

	2.  You have char temperature and char yield as a function of two parameters.  Many wanting to use char as biochar want to know the production temperature - and few can give them that.  But it appears that you have a fairly (?) linear relationship between yield and temperature.  Could you provide such a char from the data you have collected?  Perhaps char production temperature is well specified by the yield.
	Time at temperature is also important in reproducing chars.  We can back it out of your data, but knowing times more explicitly could be helpful to someone.
	Unfortunately your produced char can’t be as uniform as if made in a retort with externally supplied heat and no flow of primary air.  Can you make any statements about how char from the top might be different from that at the bottom? 
	 In a later run could you “smother” the run and then remove char in a manner that would allow that determination?  It could be important to some researcher to know more about the variation within a run.

	3.  Your plots are amazingly well performing - largely because (I guess) you have averaged two values for every data point (except in your figure 2 - which shows every data point - but without knowing which is which..  I would like to see all the data to know how reproducible a measurement is.  Can you similarly perhaps post the spread sheet that must exist?

	4.  What have you done with the massive amount of char that you have produced?  I think there might be a number of PhD candidates willing to see how radish seeds (an example) behave in small pots for the different temperature chars.

	5.   If you have saved the char, it would also be helpful for the soil types on the list to know how the char itself may be different in terms of being hydrophobic or hydrophilic,  electrically conducting or not, different bulk densities,  different pHs, etc.  Again, there may be someone reading this who would find it helpful - since you have done such a nice job in recording temperatures.

	6.  I am also interested in the fact that you apparently have full detailed time-temperature plots for all the 2*2*7 = 28 runs.   Can you share what a few of these plot look like?  (Interested in deviation from linearity near the end.)

	Again , thanks for doing such a complete and careful job.

Ron



On Dec 11, 2014, at 5:20 PM, Julien Winter <winter.julien at gmail.com> wrote:

> Hi All;
> 
> Attached is an "experimental vignette".  It is a report on a small experiment conducted to get a better understanding of natural draft TLUD design.
> 
> The height of the riser above a gas burner was doubled.  The resulting increase in draft in the burner resulted in faster gasification rates and higher temperatures in the TLUD.   Besides riser height, I have found that a number of design elements of the gas burner can increase gasification rate such as the size of secondary air holes.
> 
> I have a few more of these experimental vignette to come, such as how creating a vortex flame may not be a good idea, and how heat is lost from the side walls of the reactor, and a reasonable heap on reactor temperature for different fuels.  Now that snow is on the ground in Southern Ontario, I have more time to analyze data.
> 
> All the best
> Julien
> 
> -- 
> Julien Winter
> Cobourg, ON, CANADA
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