Preparation of dissolving pulp from oil palm empty fruit bunch by prehydrolysis soda-anthraquinone cooking method

Abstract

This study aimed to investigate the production of dissolving pulp (DP) from empty fruit bunch (EFB) of oil palm (Elaeis guineensis) as a non-wood material using a combination of prehydrolysis, soda-anthraquinone (AQ) cooking, and elementary chlorine-free (ECF) or totally chlorine-free (TCF) bleaching. Prehydrolysis was performed for 90–180 min at 150 °C. Subsequently, the prehydrolyzed EFB was subjected to several soda-AQ cooking conditions with active alkali (AA) dosages of 19, 20, and 21 % at 160 °C. The obtained pulps were bleached following ECF and TCF sequences with oxygen (O), chlorine dioxide (D0), extraction with peroxide (Ep), chlorine dioxide (D1), and peroxymonosulfuric acid (Psa) stages. The results showed that the optimal duration of the prehydrolysis was 180 min, while the best AA dosage of the soda-AQ cooking was 20 %. The determination of pulp qualities showed that ECF bleaching with the Psa–D0–Ep–D1 sequence reached 90.7 % ISO brightness, 8.5 cP viscosity, 98.6 % α-cellulose, and that TCF bleaching with the O–Psa–Ep–Psa–E sequence attained 81.6 % ISO brightness, 9.6 cP viscosity, and 95.9 % α-cellulose. The results indicated a promising potential of EFB for DP production.