Effect of Bentonite on the Combustion Behavior of Oil Palm Empty Fruit Bunch

Abstract

This study investigates the oxidative thermal decomposition (combustion) behaviour of oil palm empty fruit bunch (OPEFB) with and without a bentonite additive, characterized by thermogravimetric and differential thermal analysis (TG–DTA). Samples were heated from 30 to 1000 °C at 10 °C min⁻¹ under a flowing air atmosphere (0.5 L min⁻¹). Under air, OPEFB burned in three stages: moisture release (<150 °C), combustion of volatile matter, and combustion of the residual char, leaving an inorganic ash residue. For raw OPEFB, the moisture loss was about 5.1%, the ignition temperature (tangent method) was about 230 °C, the volatile- and char-combustion DTG peaks occurred at approximately 251 and 400 °C, and the ash residue was 12.9%. Adding bentonite (OPEFB:bentonite = 1:0.1) raised the ignition temperature to about 250 °C, shifted the volatile-combustion peak to about 276 °C, and increased the ash residue to about 19.5%. These effects are interpreted physically: the inert aluminosilicate acts as a thermal ballast and an oxygen-transport barrier that delays ignition and volatile combustion, while its thermally stable framework dominates the residual ash. Because only a single heating rate was used, no isoconversional kinetic parameters were derived. The results provide baseline combustion-characterization data supporting the use of OPEFB as a solid fuel.