(669f) Comparative Pyrolysis Kinetics for One Legume and Two Grass Hays

While the reactions involved in plant biomass are somewhat understood, there are still unknowns, particularly regarding the details of the kinetic pathways. Furthermore, there are a wide range of biomass feedstocks presently being considered for which there is no kinetic information available. This work compares the pyrolysis of one legume (alfalfa hay) and two grass hays (sudan grass hay and tall fescue). Alfalfa hay is a premium lifestock feed and would likely not be used in the future as a feed for production of biofuel, however, provides a basis upon which to compare the two grasses, which are of poor and very poor nutritional content and are likely candidates for biofuel conversion. Conventional pyrolysis using thermalgravimetric analysis (TGA) was performed on the dried, pulverized feeds. Heating rates of 5, 10, 30 and 50 oC/min were used as a basis. Mass spectroscopy was performed and and pyrolysis rate curves analyzed using a multi-process model wherein pyrolysis is assumed to be a series of discrete independent reactions. The results were used to infer alternative appraoches that account for the dramatic change in pyrolysis efficiency as a function of heating rate.