Center for Sustainable Environmental Technologies

Gasification is the conversion of carbonaceous matter (such as coal or biomass) into gaseous fuel in a low oxygen environment.  The gasifier located in 1056 H.M. Black Engineering Building gasifies between 6 and 11 lbs fuel/hour.  Fuels include ground seed corn, switchgrass, cornstover, RDF (refused derived waste), woodchips, and sawdust to name a few.  The Black gasifier is a fluidized bed gasifier meaning that a tube of sand (the bed) is mixed (fluidized) by passing air through holes in the bottom plate of the tube.  The fluidized bed is commonly chosen for gasification due to excellent mixing and heat transfer characteristics.  Gasification results in a mixture of gases (CO, CO2, CH4, H2, and others), char (solid carbon and trace minerals leaving the gasifier before reacting), water vapor, and tar (heavy hydrocarbons) which as a whole is called “syngas,” or “producer gas.”   

A new research project is underway which focuses on alkali metals effect on carbon conversion in biomass gasification.  It has been shown in the literature that alkali metals can help to catalyzed carbon to gas reactions in coal gasification.  This project investigates the effects of these same alkali metals on carbon conversion in biomass gasification.  Biomass typically contains a much higher percentage of alkali than coal potentially allowing for a higher conversion of solid carbon to gaseous fuel.  A statistically designed set of experiments is implemented to study the interconnected effects of temperature, equivalence ratio, and biomass alkali content.  Pretreated biomass is gasified and samples of bed material, char, and tar are collected.  A complete mass balance is performed on the samples.  Potassium and Sodium will be tracked by analyzing the samples with Atomic Absorption Spectroscopy.  Once complete, the experimental set can be used to generate an empirical model which can then be applied to other experimental conditions and varieties of biomass.  If successful, the project will help researchers better understand how to increase the energy value of the syngas while simultaneously decreasing the amount of time and effort required in cleaning it.