(193e) Microwave-Assisted Fast Pyrolysis (MW-FP) of Several Lignocellulosic Feedstocks

Using fast pyrolysis processes, renewable biomass resources can be converted to bio-oils that retain more than 60% of the original energy content, and these oils can then be upgraded to motor fuels or other commodity chemicals. In order to attain economic feasibility, feedstocks for commercial-scale fast pyrolysis must be obtained from a diverse set of low-cost resources for which the conversion performance is well-understood. This presentation summarizes the development of a microwave-assisted fast pyrolysis (MW-FP) reactor that employs a 3 kW microwave beam to heat samples of 1 to 2 grams at rates as fast as 200 °C/s. Liquid, solid and gas yields from as many as 8 samples per day can be measured and analyzed to determine product qualities. Because the individual experiments can be conducted in minutes rather than hours and only small quantities of material are required, MW-FP is advantageous for parametric studies exploring the effects of feedstock material, conversion temperature, and heating rate on fast pyrolysis product yields. Direct measures of product yields show that oil yield increases with volatile matter and lignin contents and decreases with potassium and sodium contents. Contents of total ash, calcium and magnesium did not appear to measurably affect oil yield on a dry, ash-free material basis. Results from the MW-FP reactor have been calibrated to floor-scale fluidized bed fast pyrolysis tests to ensure reliability of the conclusions.