Formation of value-added products from the pyrolysis of date pits: A combined experimental–DFT approach

Abstract

In arid and semiarid environments, bio-oil extraction from environmentally favorable and waste biomass is presently used as a mainstream strategy for the development of sustainable sources of energy. In keeping with this, we provide a thorough analysis of the pyrolysis of date palm pits here, focusing particularly on relevant thermal degradation profiles and pyrolytic products over a wide temperature range. Pyrolysis experiments were performed using a single-stage reactor at several temperature intervals. The temperature ranges were chosen following mass loss profiles of date pit biomass obtained by thermogravimetric analyzer (TGA) analysis. Density functional theory (DFT) calculations map out reaction pathways that dictate the decomposition of two model compounds that represented oxygen and nitrogen content in the collected condensed and non-condensed fractions. In-depth temperature-dependent profiles of pyrolytic products are thoroughly presented and analyzed. Analysis of products indicates the generation of a wide spectra of green diesel's ingredients of (i.e., long aliphatic compounds) and transportation fuels additives (alkylated benzenes). Aromatic compounds attain the highest fractions in the collected bio-oil at investigated temperature windows. Glucose derivatives appear in appreciable loads in the non-condensable fractions. The obtained mass loss curves reflect degradation curves for the most prominent biomass structural components; namely lignocellulosic, hemicellulose, and lignin. Findings presented herein shall be helpful to develop pyrolysis technologies that are suited for niche categories of biomass found in arid and semiarid regions where cultivation of standard energy crops is impractical.