[Gasification] fluidized bed temps?

[Daniel Chisholm]

Jim, 900C is reasonable and typical.

Remember that the CO2 back-reaction equilibrates around 800C, so that is
a lower bound to what you will see.  Depending on how hard
off-equilibrium you are pushing your gasifier, you might see temps
higher than that.

Is your gasifier a bubbling or circulating fluidized bed?

Remember that one of the principal advantages of fluidized beds is their
very good mixing (and in the case of circulating fluidized beds, even
moreso!).  This keeps temperatures more uniform than in fixed beds
(which is sometimes an advantage, and sometimes a disadvantage - it
depends what you are trying to accomplish)

(FWIW your 1100-1200C peak temps actually seem high-ish to me!)

Am looking forward to photos etc of your latest gasifier, all of them so
far have been interesting!  Parameters I would be interested in seeing
mentioned are fuel type, size, air flow rate, gasifier diameter,
fluidization regime (bubbling, turbulent, fast bed), your method of
dust/ash separation from the gas (cyclone or no?), positive or negative
pressure, etc.


w.r.t. "the CRC book" mentioned (Basu's 2006 book), I have been reading
mine quite a bit since I got it, but am not really in a position to
write a book review on it.  It does seem to have quite a number of small
errors in it (the perils of buying a first edition ;-), but there is a
great deal of good material in it which I find quite useful.  It is
mostly oriented to large scale (power plant) circulating fluidized bed
combustors (mostly coal), though there is some incorporation of biomass
gasifiers too (not as fully fleshed-out as I would like to see).  I
particularly like the book's well-worked-out examples, which use actual
real engineering values (e.g. temperatures and viscosities, cylcone
inlet velocities, etc).




-- 
- Daniel
Fredericton, NB  Canada