TAR FORMATION IN CORNCOB GASIFICATION
Abstract
Gasification of corncobs was studied to determine the amounts of tar and condensates produced. Variables studied included corncob particle size, moisture content, airflow rate, and reactor's operational mode (updraft and downdraft). The effect of temperature was also studied by running first with the unit noninsulated, and second adding insulation in the regions where pyrolysis, oxidation and gasification occurs. Results indicate that, over the range studied, tar and condensate yield increases with increasing fuel moisture, and that it does vary with air flow rate through the reactor. Updraft gasification of corncobs was found to produce about 3 to 4 times more tar than the downdraft gasification. Insulation of the reactor's pyrolysis, oxidation and reduction zones increased their operating temperature and significantly reduced the yield of tar and condensate in the gas stream. Production of tar and condensate were also found to fall off with respect to time. Ultimate analysis of the corncobs, corncob charcoal, condensate and tar was performed and constituent formulas were developed. Gas from the producer was also studied and its composition, heating value, molecular weight, density and specific heat were found. Reactor's mass and energy balance were also performed and gasifier efficiency was found to average 64 percent. Addition of Oxygen in the reduction zone of the gasifier was found to have potential in reducing tar yield in the gas stream. Further studies however, are needed and should be done before this result can be considered final.
Degree
Ph.D.
Subject Area
Agricultural engineering
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