Insights into hydrothermal treatment of biomass blends: Assessing energy yield and ash content for biofuel enhancement

PLoS One. 2024 May 22;19(5):e0304054. doi: 10.1371/journal.pone.0304054. eCollection 2024.

Abstract

This study explores the Hydrothermal Carbonization (HTC) treatment of lignocellulosic biomass blends, delving into the influence of several key parameters: temperature, additive nature and dosage, residence time, and biomass composition. Rapeseeds, Pinus radiata sawdust, oat husks, and pressed olive served as the studied biomasses. One hundred twenty-eight experiments were conducted to assess the effects on mass yield (MY), energy yield (EY), higher heating value (HHV), and final ash content (ASH) by a Factorial Experimental Design. The derived model equations demonstrated a robust fit to the experimental data, averaging an R2 exceeding 0.94, affirming their predictive accuracy. The observed energy yield ranged between 65% and 80%, notably with sawdust and olive blends securing EY levels surpassing 70%, while rapeseed blends exhibited the highest HHV at 25 MJ/kg. Temperature emerged as the most influential factor, resulting in an 11% decrease in MY and a substantial 2.20 MJ/kg increase in HHV. Contrastingly, blend composition and additive presence significantly impacted ASH and EY, with all blends exhibiting increased ASH in the presence of additives. Higher initial hemicellulose and aqueous extractive content in raw biomass correlated proportionally with heightened HHV.

MeSH terms

  • Biofuels* / analysis
  • Biomass*
  • Brassica rapa / chemistry
  • Hot Temperature
  • Lignin / chemistry
  • Olea / chemistry
  • Pinus / chemistry
  • Temperature

Substances

  • Biofuels
  • lignocellulose
  • Lignin

Grants and funding

FV received research funding as part of the ModSim group at the National University of Chimborazo (Universidad Nacional del Chimborazo, Ecuador). The funds were allocated by the Vice Presidency of Research for data analysis, manuscript writing, and covering the Article Processing Charges (APC). The URL is https://www.unach.edu.ec/vicerrectorado-de-investigacion-vinculacion-y-posgrado-ele/. Additionally, research support was provided by BMBF150067 and Dirección de Investigación Científica y Tecnológica, Universidad de Santiago de Chile (DICYT) 062317EP_Ayudante to facilitate data collection and experimental work. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.