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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Energy Res. | doi: 10.3389/fenrg.2019.00084

Air and Steam Gasification of Almond Biomass

 Zach McCaffrey1*,  Peter Thy2, Michael Long2, Melina Oliveira3, Li Wang2, Lennard Torres1, Turkan Aktas4, Bor-Sen Chiou1, William Orts1 and  Bryan M. Jenkins2
  • 1United States Department of Agriculture (USDA), United States
  • 2University of California, Davis, United States
  • 3Bioenergy Research Institute, São Paulo State University, Brazil
  • 4Namik Kemal University, Turkey

Experiments were performed to characterize the gasification products of almond shells removed in nut processing operations and to determine the effect of gasifying media on bed agglomeration. Agglomeration in the reactor bed due to reactions between the flue gas and the bed medium was significantly worse under air gasification than under steam gasification. The higher heating value during air gasification of almond biomass ranged from 4–6 MJ kg-3, whereas gas concentrations ranged from 14%–18% H2, 3–4% CH4, 43– 50% N2, 16 – 19% CO, and 16 –17% CO2. For steam gasification, higher heating value was 10–12 MJ kg-3 and gas concentrations were 35–40% H2, 5 – 7% CH4, 17 – 21% N2, 18 – 21% CO, and 16 – 18% CO2. The high level of potassium in the almond shells led to strong corrosion of the bed material due to flue gas transport of potassium compounds. As a result of long duration and elevated temperature approaching 1000 oC, potassium together with silica are mainly transported as aerosol melt particles that form an adhesive resulting in enhanced agglomeration.

Keywords: Almond shells, Air gasification, Steam gasification, Power generation, agglomeration

Received: 20 Mar 2019; Accepted: 07 Aug 2019.

Edited by:

Sachin Kumar, Sardar Swaran Singh National Institute of Renewable Energy, India

Reviewed by:

Fehmi Akgun, TUBITAK Marmara Research Centre Energy Institute, Turkey
Pratik N. Sheth, Birla Institute of Technology and Science, India  

Copyright: © 2019 McCaffrey, Thy, Long, Oliveira, Wang, Torres, Aktas, Chiou, Orts and Jenkins. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Zach McCaffrey, United States Department of Agriculture (USDA), Washington D.C., United States, zach.mccaffrey@ars.usda.gov