Regeneration of spent bleaching clay by heat regeneration for re-use in bleaching of clyde palm oil.

Abstract

Spent bleaching clay (SBC), a solid waste generated from the palm oil refinery, may be recycled rather than being simply disposed of in landfills. The aim of this research was to regenerate SBC by solvent extraction and heat treatment, evaluate the performance of the heat-treated SBC in bleaching crude oil and determine the optimum regeneration conditions. Two regeneration methods were used, i.e. (a) solvent extraction followed by heat treatment, and (b) direct heat treatment. Heat treatment was conducted in a box furnace at temperatures of 400°C, 500°C and 800°C. The color of bleached palm oil was used to determine the relative bleaching efficiency of regenerated SBC. SBC regenerated by direct heat treatment [denoted as heated regenerated spent bleaching clay (HRSBC)] had higher relative bleaching efficiency, at all regeneration temperatures, than SBC regenerated by solvent extraction followed by heat treatment [denoted as deoiled-heated regenerated spent bleaching clay (DHRSBC)]. This is because moisture, impurities and dirt were more completely removed by direct heating than by solvent extraction. The optimum regeneration temperature was 500°C. Highest relative bleaching efficiency was achieved by sample HRSBC at 500°C.