[Gasification] REPLY: Push-Pull or Pressure-firing vs Suction-Firing

[andy schofield]

Dear Douglas Diaz, and chemists,

  To keep a Gasification system simple, I would suggest using induced draft. 
It not only is safer, It also is easier to build and operate. Induced draft 
(Where the fan takes suction on the gasification reactor) is the most common 
method used to move air through the fuel-bed in our smaller gasifiers.

  However, anytime gas pressure can be increased on a combustion process, 
the rate of reaction is  increased. Please see Nye Thermodynamics NT-6 for 
example, and compare fuel-thruput to a normal parlor stove (Benjamin 
Franklin). The physical size and weight of a reactor (for a given 
through-put) could be reduced greatly, if the air and fuel-bed is operated 
at several atmospheres above ambient. Also the shaft-power requirement to 
move any gas (at a given mass per hour) is less at a higher pressure, lower 
temperature than at a lower pressure, higher temperature.

  I smelled ammonia after a short run, pressure-firing my gasifier once, but 
I dont know why. Nitrogen from the air may be combining with the hydrogen 
knocked off my cherrypit fuel
somehow. Taking a look at an ammonia molecule, I see two atoms of hydrogen 
attached in a normal looking way, and a third atom of hydrogen attached in a 
wierd way (I dont understand) to a single nitrogen atom. If the hydrogen 
atoms could be pulled loose from the nitrogen (like picking cherries off a 
tree), engine-cylinder combustion-chamber flame speed could approach that of 
octane (natural gasoline). I hope someone can explain this.

Andy Schofield
Great Lakes Renewable Fuels

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