The influence of mild air conditions on the chemical properties and pyrolysis behavior of empty fruit brunches during torrefaction

Journal article

Authors/Editors

Strategic Research Themes

Reliability Engineering (Quality and Life cycle management)

Publication Details

Author list: Jadsadajerm S.; Phongaksorn M.; Areechon K.; Thabwaew P.; Jongsomjit B.; Laosiripojana N.; Pimsamarn J.

Publication year: 2023

ISSN: 21906815

URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85171172957&doi=10.1007%2fs13399-023-04851-0&partnerID=40&md5=1b52d19f349fd0994c4fe5564920af6c

Languages: English-Great Britain (EN-GB)

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Abstract

Torrefaction of empty fruit bunches (EFB) was conducted in the presence of mixed air and nitrogen to obtain desired oxygen concentrations between 2.5 and 10%. The effect of oxygen concentrations (0–10 vol.%) and temperatures (240–300°C) on the chemical properties and pyrolysis behaviors of torrefied products were investigated. The mass yield decreased significantly with increasing oxygen concentration and temperature. When the oxygen concentration rose from 0 to 10%, the carbon content in EFB torrefied at 300°C increased from 64.64 to 66.91 wt%. Simultaneously, the oxygen content in EFB decreased, reaching as low as 25.78 wt%. The higher heating value of the torrefied EFB at 300°C was remarkable, as high as 27–28 MJ/kg. The carbon and energy yields of torrefied EFB decreased as the oxygen concentration rose to 10%. However, these values remained above 45% and were higher than the torrefied mass yield. The response surface methodology revealed that low air was suitable for the proposed torrefaction. The pyrolysis behavior results showed that the presence of oxygen during torrefaction enhanced the biochar yield of torrefied EFB. The observed phenomenon might be attributed to the occurrence of cross-linking reactions during pyrolysis promoted by the presence of oxygen during torrefaction. The results of thermogravimetric and XRD analyses of cellulose suggested that oxygen played a vital role in modifying the cellulose structure in EFB, resulting in a higher char yield. These effects were essential for optimizing the torrefaction process under the limited air concentration and enhancing the biochar production from the torrefied biomass. Graphical abstract: [Figure not available: see fulltext.]. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Keywords

Oxidative torrefaction