Torrefaction of Almond and Walnut Byproducts

Frontiers in Energy Research

Delilah F. Wood¹  Lennard Torres¹  William John Orts¹  Bor-Sen Chiou¹  Zach McCaffrey¹  Saulo Rocha Ferreira²  Luiz Eduardo Silva³ 

[1] Bioproducts Research Unit, Western Regional Research Center (WRRC), United States Department of Agriculture (USDA), Albany, CA, United States;Civil Engineering Department, Federal University of Lavras, Lavras, Brazil;Forest Science Department, Federal University of Lavras, Lavras, Brazil;

关键词: torrefaction;    almond shells;    walnut shells;    almond wood;    biomass power;   

DOI  :  10.3389/fenrg.2021.643306

来源: Frontiers

【 摘 要 】

While the US nut industry is growing, markets for nut by-products, particularly nutshells and tree prunings, have not kept pace. Torrefaction is a thermochemical process used to improve physicochemical properties of biomass for energy and other applications. The goal of the paper was to characterize the effects of a range of torrefaction conditions on the properties of nut by-product feedstock. The process consists of thermal treatment of biomass at a temperature between 200 and 300°C in the absence of oxygen, where final material properties of the torrefied biomass depend on the temperature, heating rate, and residence time. In general, torrefied biomass exhibits higher hydrophobicity and calorific value with reduced moisture absorption compared to untreated biomass, making it an ideal fuel source for energy applications compared to raw biomass. In this study, almond shells of soft, semi-soft, and hardshell varieties, as well as walnut shells and almond wood, were torrefied at two different temperatures (230 and 290°C) and three different residence times (20, 40, and 60 min) in order to characterize the physicochemical properties. The thermal behavior of raw and heat-treated biomass was investigated by TGA analysis, elemental analysis, pH, helium pycnometry, FTIR spectroscopy, and dynamic vapor sorption analysis.

【 授权许可】

CC BY