Product Distribution from Fast Pyrolysis of Biomass

Center for Sustainable Environmental Technologies

Product Distribution from Fast Pyrolysis of Biomass

 

Biomass, being the only current sustainable source of organic carbon, is recognized as an attractive feedstock for fuels and chemicals production. Fast pyrolysis is a process aimed towards converting biomass into liquid product often called ‘bio-oil’. Bio-oil has been identified as a potential renewable resource which can be processed analogous to the crude petroleum oil using the existing petroleum refinery infrastructure to yield an array of useful products.  However, it is not feasible to put this technology into commercial application until the quality of bio-oil is improved which ultimately depends on the composition of biomass (cellulose, hemicelluloses, lignin and minerals content) from which it is produced and the process parameters, such as reaction temperature, heating rates, and bio-oil vapor residence time before it is condensed.  Bio-oil is a complex mixture of several different chemical species which can be broadly classified into hydroxyaldehydes and ketones, carboxylic acids, anhydrose sugars and phenolic compounds.

Figure 1. Species resulting from the pyrolysis of cornstover at 500oC

Abundant literature is available focusing on optimizing the bio-oil yield, however little attention was provided to the quality of the bio-oil produced. Chemical phenomena referred as primary and secondary reactions have been traditionally avoided when modeling the pyrolysis process. With the increasing interest in usage and upgrading of bio-oil, it is imperative to discern the effect of secondary reactions and accurately predict the yields of species present in bio-oil

Figure 2. Pyrolyzer-GC-MS system at CSET

 

We, at CSET, are using a micro-pyrolyzer, which is directly connected to a GCMS, to establish the relationships between chemical structures of lignocellulosic constituents of biomass and process parameters to the resulting product distribution based on the primary reactions.  Various biomass materials and chemical compounds chosen as model compounds to mimic biomass components are pyrolyzed.  The fast pyrolysis vapor product stream is sent directly to a GC/MS to have its composition analyzed.   Additional complexities accounting for secondary reactions and reactor configuration are also being studied with the help of 100g/hr bench scale fluidized bed reactor.

Reserch done By:
Pushkaraj Patwardhan

 

For inquiries related to this research program, please contact Dr. Robert C. Brown (rcbrown@iastate.edu) and/or Dr. Justinus A. Satrio (jasatrio@iastate.edu).