Briquetting of palm fibre and shell from the processing of palm nuts to palm oil

Abstract

Malaysia is the major producer of palm oil in the world. It produces 8.5 million tonnes per year ( 8.5×10 6 t y −1 ) of palm oil from 38.6×10 6 t y −1 of fresh fruit bunches. Palm oil production generates large amounts of process residues such as fibre ( 5.4×10 6 t y −1 ), shell ( 2.3×10 6 t y −1 ), and empty fruit bunches ( 8.8×10 6 t y −1 ). A large fraction of the fibre and much of the shell are used as fuel to generate process steam and electricity in the palm processing mill itself. However, much is wasted by pile burning in the open air with attendant air pollution, dumped in areas adjacent to the mill, or utilized as manure in the palm oil plantation. In this paper, an attempt has been made to convert these residues into solid fuel. The palm shell and fibre is densified into briquettes of diameter 40, 50 and 60 mm under moderate pressure of 5– 13.5 MPa in a hydraulic press. Experiments are carried out to determine density, durability, impact and compressive strength of the briquettes. The heating value, burning characteristics, ash and moisture content are other objects of the study. A relationship between press pressure and the briquette density has been established. The produced briquettes have densities between 1100 and 1200 kg m −3 . The briquettes properties are quite good with good resistance to mechanical disintegration, and will withstand wetting. The gross calorific value is about 16.4 MJ kg −1 (maf), and the ash content is about 6% and the equilibrium moisture content is about 12%. Further work is required to acquire complete understanding of the densification process before good quality and durable briquettes could be made free from cracks.