Changes in the devolatization kinetics induced by washing pretreatments of short- and long-aged food crop residues

Abstract

Thermogravimetric curves are measured and modeled to quantify the changes induced by dilute acid or hot water washing on the devolatilization of short- and long-aged potato crop residues. The pretreatments cause more similar behaviors. A six-step devolatilization mechanism for four pseudo-components, previously developed for raw materials, is still applicable. The activation energies remain unvaried whereas small changes in the pre-exponential factors describe the displacement of the devolatilization process at higher temperatures. Instead, the nature and amounts of pseudo-components are significantly modified, especially for dilute acid washing and the short-aged sample. The pseudo-components pectin-hemicellulose and cellulose-starch are enriched in hemicellulose and cellulose, respectively. The corresponding total amounts of volatile generated increase from 19 up to 23–26wt% and from 19–26 up to 37–45wt%, in the same order. The volatile product yields released from the pseudo-component lignin-protein are practically unaltered, but lignin is likely to become largely predominant.