[Gasification] Moisture, Humidity & Inlet Air

[doug.williams]

Hi Greg, and Colleagues,
You report:

> the Relative Humidity (RH) of
> the air went quite high as fog really rolled in (we are talking 1 foot in
> front of your face, kinda fog) the noted RH was well into the 80% mark, 
> and
> the gasifier started "WEIRDING OUT" on me, drastic flare changes, puffing
> etc.

I guess you have worked out by now what was actually happening, which is a 
problem of gasifiers that are using preheated air inputs. The moister vapour 
turned to steam, and in it's expansion from water, began to displace the 
incoming air down the vertical air pipes to the nozzles. Injecting steam 
directly into the oxidation zone, instead of air, quenches the oxidation 
temperature, and creates a ever reducing temperature of, puff of ignition, 
followed by the quench.

> I have a couple bags of "Desiccant pellets" (pellets are about the size of
> suckers w/o the stick) that I use in the "air dryer" on my shop
> air-compressor.

An excellent solution , but not available to many who might be placed in 
this situation , that is if they are even aware of the cause of the problem. 
It does however, high light that many problems are resolved by adding 
additional components.  In this instance, I am pretty sure that all you had 
to do was take the plugs out of your tee fittings at the nozzles, and feed 
the air directly in without preheat. This allows the water vapour to enter 
directly onto the incandescent char, where it will thermally crack into H2. 
It should be easy to test so long as you have the fog (:-), but I can say 
that we had this situation in Northern Ireland and it worked fine., but we 
do not preheat air.

Your experience should be noted by those developing new innovative 
gasification designs. A gasifier works in the development location because 
of all the factors that create the phenomena you observe, and possibly rely 
on to sell your ideas. In another place, it just has problems that in 
ignorance were never foreseen.

Hope this helps.
Doug Williams,

Fluidyne Gasification.