[Gasification] Gasification Air/Fuel Ratio

[Brennan R Henderson]

Greg,

Somewhere in the gasification archives Thomas Reed wrote a list of  
gasification rules of thumb. Because most of the archives are  
unavailable right now, I can't
find the posting, but I wrote down that the air/fuel ratio was 1.5:1  
by mass.

> if it was mass, the
> amount of air consumed would be astronomical.

I disagree, Lets say we want to gasify 100 lbs (45.45kg)  of MAF wood  
in one hour  at a 1.5:1 air/fuel ratio by mass

150 lbs (68.18 kg)/hour air + 100 lbs (45.45)/hour MAF wood

At sea level and at 20 °C dry air has a density of approximately 1.2  
kg/m3

56.8 cubic meters/hour

.946 cubic meters/min

33.43 cubic feet/min , Not a huge air flow on my Dwyer 5-50 scfm  
rotameter
with 1" pipes in and out.

It would be interesting to see the airflow entering your gasifier  
tuyeres versus the wood input per hour.

Brennan Henderson
Vernon BC Canada


On 14-Nov-06, at 7:54 PM, Greg Manning wrote:

>
> Greetings Brennan and list members.
>
> Brennan, some light on interpretation, page 24 I do not know the  
> tables, but
> the pages in the PDF document are in volume as a ratio. if it was  
> mass, the
> amount of air consumed would be astronomical.
>
> Any gasifier (up/down or fluid) has a very small output, compared  
> to the
> same physical size equipment dealing only in combustion.
>
> Gasifiers are NOT combustors, rather, they are thermally driven matter
> reformers. One can substitute an external source of heat, in lue of  
> the
> small portion of combustion within a gasifier, and run the gasifier  
> in this
> mode, however, the amount of external heat needed to produce the  
> reaction,
> out weighs the result.
>
> Air is needed for partial combustion, leaving a pipeable gas that  
> can be
> used "un-coupled" (loose coupled) from the gasifier (referring to  
> close
> coupled dual combustors, vs. gasifiers). after the initial  
> combustion for
> the required heat to drive the reaction, air is NOT required (or  
> wanted) at
> later stages of gasification (thermally driven chemical reduction).
>
> Do NOT compare combustor levels of air needed, to gasifiers, this will
> confuse even me.......(not that I know much, in the first place).
>
> Your best answers would be to ask Mr. Tom Reed, as I believe they  
> are his
> articles in the first place.
>
> Greg Manning,
> Brandon, Manitoba, Canada
>
>
>