(135f) Fast Pyrolysis of Algal Biomass

Fast pyrolysis experiments with algal biomass are being performed in laboratory fluidized bed reactors. These experiments are being carried out at 450, 500, 550 and 600°C to study the effects of temperature on biomass conversion to gas, oil and char products. These conditions were chosen based on thermo-gravimetric analyses of the feed stocks which showed that most of the thermal decomposition of algal biomass occurred within this temperature range. Our reactors are purged with helium to maintain inert atmosphere for pyrolysis reactions. The high flow rates of helium (approximately 1L/min) also fluidize the biomass and reduce the residence time of hot volatile vapors to approximately 5s. During our experiments, liquid products are collected by condensing with cold water; gas formation is monitored using mass flow meters and gas composition is measured using an online gas chromatograph equipped with a pulsed discharge helium ionization detector. Solid residues (or char) are recovered from the reactor at the end of the experiment. Proximate- (volatile matter, moisture content, ash and fixed carbon) and ultimate- analyses (C, H and N) of the feedstock and products is performed using various standard methods to close overall and element-specific mass balances. Additionally, bio-oil is analyzed using an mass spectroscopy to identify specific compounds and the overall molecular weight distribution of this product. The heating values of biomass, bio-oil and bio-char are being calculated. The results of these investigations will be presented and discussed.