[Gasification] updraft and stratified downdraft sizing questions

[jim mason]

the BEF books have lots of info on sizing traditional downdraft
gasifiers of the imbert type design.  but i can't find any info on
sizing and gas rate ranges on updrafts or stratified downdrafts.

i can elaborate from gas rates for x throat diameter in an imbert, and
equate throat in an imbert to vessel size of updraft / stratified
downdraft.  imbert gas rates are between .3 and .9 cubic meters/h for
each square centimeter of throat (normallized to atmospheric temp and
pressure).   but that is also with constricted air, not air fully open
from the top or bottom.

in an imbert, the ratio of total cross sectional area in the tuyeres
for air inlet to the cross sectional area of the throat is around
.004:1 to .008:1.  in an updraft or a stratified downdraft, it is 1:1.
 quite a difference.  so just equating gas rates between throat area
and vessel size in updraft/downdraft seems not a good approximation.

i'm curious to know how my gas pull rate on the updraft rig i built
last week falls within desired ranges.  and i'm equally curious to
know how to size the stratified downdraft i'm working on next.

any rules of thumb out there?

j