The Effects of Autohydrolysis Pretreatment on the Properties of OPT Pulps for the Production of Dissolving Pulp

Abstract

This preliminary study investigated an environmentally friendly method for fabricating cellulose-rich dissolving pulp from Oil Palm (<i>Elaeis guineensis</i>) Trunk (VBOPT) fibre. This method encompassed an autohydrolysis pretreatment followed by soda pulping procedures. The impact of autohydrolysis pretreatment on the separation of lignocellulosic components was scrutinised to facilitate the production of chemical cellulose. Autohydrolysis was performed on VBOPT fibre for 60 min at temperatures ranging from 140°C to 160°C, maintaining a solid-to-liquid ratio of 1:8. The yield of the prehydrolysed OPT varied between 73.5% and 91.5%. The chemical composition of the prehydrolysed VBOPT fibre comprised 70.6–80.0% holocellulose, 63.7–87.1% α-cellulose, 7.4–10.9% ß-cellulose, 5.5–25.4% γ-cellulose, and 21.5–26.6% lignin. The prehydrolysed OPT was subsequently subjected to alkaline pulping under fixed conditions: a temperature of 160°C, a treatment time of 60 min, a chemical charge of 25%, and a solid-to-liquid ratio of 1:6. The resultant pulp exhibited properties such as a screening yield of 41.5–46.4%, a kappa number of 4.5–9.6, and α, β, and γ cellulose content of 89.4– 98.1%, 1.5–5.3%, and 0.4–6.9%, respectively. Based on the chemical composition of the OPT biomass before and after pretreatment, as well as post-alkaline cooking, the autohydrolysis pretreatment was determined to significantly influence the resultant pulp. A more comprehensive understanding of the interdependence of autohydrolysis and pulping processes can be achieved by executing an optimisation study focusing on key parameters of autohydrolysis and pulping, including temperature, treatment duration, and chemical charge.