Campus Units

Agricultural and Biosystems Engineering, Chemical and Biological Engineering, Mechanical Engineering, Bioeconomy Institute (BEI)

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

9-1-2019

Journal or Book Title

Applied Energy

Volume

249

First Page

276

Last Page

285

DOI

10.1016/j.apenergy.2019.04.154

Abstract

Heat transfer is the bottleneck to fast pyrolysis of biomass. Although the enthalpy for pyrolysis of biomass is relatively small operation at temperatures around 500 °C constrains heat carrier selection to inert gases and granular media that can sustain only modest thermal fluxes in practical pyrolysis systems. With heat transfer controlling the rate of pyrolysis, reactor capacity only scales as the square of reactor diameter and does not benefit from economies of scale in building larger reactors. We have eliminated this heat transfer bottleneck by replacing it with partial oxidation of pyrolysis products to provide the enthalpy for pyrolysis in a fluidized bed reactor, a process that can be described as autothermal pyrolysis. The oxygen-to-biomass equivalence ratio depends upon the kind of biomass being pyrolyzed and the level of parasitic heat losses from the reactor, but under conditions that simulate adiabatic operation, equivalence ratios are around 0.10, compared to 0.20 or higher for autothermal gasifiers. At this low equivalence ratio, there was no significant loss in bio-oil yield when operating the reactor autothermally (64.8 wt%) as compared to conventional pyrolysis (64.4 wt%). Carbon balances indicate that less valuable pyrolysis products (char and aqueous, bio-oil light ends) are consumed via partial oxidative reactions to provide the enthalpy for pyrolysis. While the carbon yields of char and bio-oil light ends decreased by 25.0% and 21.3%, respectively, the most valuable pyrolysis product (bio-oil heavy ends) only decreased 8.0%.

Comments

This is a manuscript of the article Polin, Joseph P., Chad A. Peterson, Lysle E. Whitmer, Ryan G. Smith, and Robert C. Brown. "Process intensification of biomass fast pyrolysis through autothermal operation of a fluidized bed reactor." Applied Energy 249 (2019): 276-285. DOI: 10.1016/j.apenergy.2019.04.154. Posted with permission.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Copyright Owner

Elsevier Ltd.

Language

en

File Format

application/pdf

Available for download on Thursday, May 06, 2021

Published Version

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