Modeling Heat Transfer and Reaction Kinetics of Biomass in Pyrolysis Feeding Systems

Joseph Samaniuk, Jonathan Stickel, Tim Dunning, Daniel Carpenter, Jessie Troxler

Research output: NRELPresentation


Biomass feedstocks can be used to produce low carbon-intensity chemicals and liquid fuels by displacing fossil-fuel sources. Pyrolysis is the thermal decomposition of biomass in the absence of oxygen and can be used to produce crude biofuels. A typical feeding mechanism for pyrolysis reactors is by lock hopper followed by a horizontal auger feeder. Particle agglomeration and plugging of the auger screw are regularly occurring phenomena that is detrimental to the process since it results in the need for periodic inspection and cleaning. The underlying mechanisms leading to agglomeration and plugging are unclear, but a working hypothesis is that heat from the reactor raises the temperature of the biomass in the feeder to the point at which preliminary decomposition reactions occur and produce "sticky" products. Using principles of heat and mass transfer, we derived one-dimensional differential equations for heat flow from the pyrolysis reactor through the auger feeder. Temperature profiles were solved from the system of one-dimensional differential equations using the shooting method. Subsequently, we used the temperature profiles as a one-way coupling to a reaction model for the biomass in the feeder. Kinetic models were adopted from the literature and used to predict the formation of intermediates, products, char, extractives, and metaplastics as well as phase changes along the auger feeder. Species were identified that correlated with softening of the biomass, causing it to become sticky and plug the feeder. We will discuss the details of this work, our findings, and the direction of future work that includes fully coupled transport and reaction-kinetics simulations.
Original languageAmerican English
Number of pages46
StatePublished - 2021

Publication series

NamePresented at the AIChE Annual Meeting, 7-12 November 2021, Boston, Massachusetts

NREL Publication Number

  • NREL/PR-2800-79730


  • biomass pyrolysis
  • reaction kinetics
  • transport phenomena


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