[Stoves] Mis-information

Gordon West gordon.west at rtnewmexico.com
Sun Apr 1 05:52:13 MDT 2018


Ron (I’ll try your method of responding here).

> In any case, the expanded gas volume has to get out somehow, potentially even through holes assumed to be ventures. 
	[RWL:  But TLUDs provide no such holes (in any I have seen).  The word “ventures”  looks like a typo for “vents” or “Venturis”?  The term Venturi implies air flow past a “vent”  not in or out of.  Or “through”.
		GW: Autocorrect got me - that was supposed to be venturis.

> During experiments we did in capturing syngas from a large TLUD (made from a vertical 500 gallon propane tank), we calculated that there was a 4:1 expansion of syngas volume over the combustion air volume. That increase in volume and pressure has to go somewhere.
	[RWL:  Can you rephrase this?  The syngas creation is associated with low amounts of primary air - and we know the secondary air has to be 5-6 times larger to convert the CO and H2 to CO2 and water (which chemical reactions create a pressure drop as 3 particles convert to two).   My concern is over your phrase “combustion air volume”.  In any case,  we know that air flow is always from high pressure regions to lower (even with a Venturi effect - which low pressure is occurring in the faster flowing fluid).
		GW: We were using forced draft primary air through the bottom of the tank. The top had a sealing lid through which the tank was loaded and the feedstock lit, then closed after the burn became robust. There was also an exhaust pipe exiting the tank at the top to carry the syngas to ground level and into a ceramic lined 55 gallon drum swirl burner. The primary air input had to create enough static pressure to overcome both the expansion of gases at the MPF and the resistance (friction and buoyancy) of pushing the syngas down a 12' vertical pipe. We crudely measured primary air velocity using a handheld anemometer and calculated mass airflow. The 4:1 (produced gas to input) figure came from reading other research, so I can’t vouch for its correctness, but we used it to calculate an appropriate diameter for the syngas exhaust pipe. We did not measure or attempt to calculate static pressure, except to guess at it from the fan manufacturer’s stated specifications. 

Gordon




> On Mar 31, 2018, at 10:18 PM, Ronal W. Larson <rongretlarson at comcast.net> wrote:
> 
>> In any case, the expanded gas volume has to get out somehow, potentially even through holes assumed to be ventures. 
> 	[RWL:  But TLUDs provide no such holes (in any I have seen).  The word “ventures”  looks like a typo for “vents” or “Venturis”?  The term Venturi implies air flow past a “vent”  not in or out of.  Or “through”.
> 
>> During experiments we did in capturing syngas from a large TLUD (made from a vertical 500 gallon propane tank), we calculated that there was a 4:1 expansion of syngas volume over the combustion air volume. That increase in volume and pressure has to go somewhere.
> 	[RWL:  Can you rephrase this?  The syngas creation is associated with low amounts of primary air - and we know the secondary air has to be 5-6 times larger to convert the CO and H2 to CO2 and water (which chemical reactions create a pressure drop as 3 particles convert to two).   My concern is over your phrase “combustion air volume”.  In any case,  we know that air flow is always from high pressure regions to lower (even with a Venturi effect - which low pressure is occurring in the faster flowing fluid).
> 

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