Hydrothermal Carbonization of Corncob Residues for Hydrochar Production

TLDR

Corncob residues are an underutilized lignocellulosic waste that can be upgraded into a high‑quality energy resource. The authors used hydrothermal carbonization to produce high‑heating‑value hydrochar from CCR. After 230 °C, 1.5 h hydrothermal treatment, the hydrochar’s HHV increased 47 %, and FT‑IR, TG/DTG, and XRD analyses revealed dehydration and decarboxylation as the main C and O reduction pathways, indicating a promising mild‑condition upgrade of CCR.

Abstract

Upgrading corncob residues (CCR) to a high quality energy resource is an effective utilization of an underutilized industrial lignocellulose waste. A hydrothermal carbonization technique was therefore employed to generate a high heating value (HHV) hydrochar. Results showed that its HHV increased 47% after treatment at 230 °C for 1.5 h. Decreases in H/C and O/C verified that reductions in C and O reactions were occurring following hydrothermal carbonization. The chemical and thermal properties of the final hydrochar as analyzed by FT-IR, TG/DTG, and XRD analyses indicated that dehydration and decarboxylation were the predominant pathways for the C and O reductions. The present hydrothermal carbonization process is offered as a promising approach to upgrade CCR to a high heating value hydrochar under mild conditions.