Gasifier Experimenters Kit

Gasifier Experimenters Kitconstriction and reduction has been underwayfor some time. This suggests the significantlypreheated air is increasing the combustion rateso the "normal" distance from the nozzles tothe reduction constriction for combustion tocomplete is now too long. Or in other words,we need to lower the nozzles to again placethe finish of combustion right at theconstriction of the reduction bell. (note theconfiguration help a simple TC provides).The bottom of the reduction bell isconsistently 600-650C. I was very surprised tosee this temp stay steady across a very largerange of pull rates. The only way I could getthe bottom of the reduction bell above thistemp was to overpull the reactor, which pulledthe reduction down onto the grate and axiallyoutward, typically burning off the gas cowlingpaint. I was baffled until I pulled out theBoudouard equilibrium reaction chart anddiscovered a "knee" in the graph right wheremy temp was stuck. 600-650C is "knee" in theboudouard reaction rate change, below whichthe reduction of co2 to co slows to at pointwhich is not terribly relevant.Clearly there is a wealth of configurationoptimization and gas flow rate limits that canbe derived simply from knowing the top andbottom temps of the reduction bell. More onthis in the next report.Grate to Gas Exit:The syngas loses about 200-300C from thebottom of the reduction bell to the edge of thegrate at the gas cowling. Temps here at thewall before the gas rises up the gas cowlingwandered between 350-450C. I was surprisedto see this significant of drop just from thereduction bell to the edge of the grate, as thishttp://www.allpowerlabs.org/gasification/gek/gekreports/report3/report3.html (8 of 10) [10/9/2008 08:04:38]