ARS | Publication request: Fast pyrolysis of guayule biomass

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 2, 2009
Publication Date: March 21, 2010
Citation: Mcmahan, C.M., Boateng, A.A., Cornish, K. 2010. Fast pyrolysis of guayule biomass. 239th American Chemical Society (ACS) Meeting and Exposition, March 21-25, San Francisco, CA.

Interpretive Summary: Guayule (Parthenium argentatum), a woody desert shrub indigenous to the southwestern USA, produces high molecular weight cis-1,4-polyisoprene, and has entered the commercial arena as an alternative material for the manufacture of medical devices safe for people suffering from Type I IgE-mediated Hevea latex allergies. Cultivation of guayule for latex production provides the favorable economics to support commercialization; however, use of crop residues to produce bio-energy could have a major impact on sustainability of this new industrial crop. Latex extraction leaves ~90% of the crop biomass as a finely-divided, free flowing feedstock suitable for conversion to biofuels. Our collaborative research is exploring several avenues to bio-energy, including biochemical and thermochemical conversion. Thermochemical conversion produces bioenergy while consuming the entire plant, significantly improving the value proposition for profitable and sustainable growth of domestic rubber in the USA.

Technical Abstract: The sustainability of industrial crops like guayule, a domestic source of natural rubber, can be significantly enhanced by utilization of biomass residues. Guayule bagasse, a free-flowing solid, presents an attractive bioenergy feedstock due to its high energy content, small particle size, and high density. Moreover guayule is harvested year-round providing a continuous source of feedstock. One option for feedstock conversion is fast pyrolysis. Guayule bagasse and whole shrub was converted into bio-oil, charcoal, and non-condensable gases by fast pyrolysis at ~ 500°C in a bench-scale fluidized bed reactor. Over a sand medium, bio-oil was produced in the 60% yield range without catalyst. Bio-oils from guayule had energy content around 30 MJ/kg, 75% of the value of heavy fuel oil. The energy content of guayule was determined based on Py-GC/MS pyrograms, and the contributions of natural resin and rubber components quantified. The stem-derived latex-extracted bagasse contained the highest thermochemical energy potential.