Performance Evaluation of Raphia Palm (R. vinifera) Seeds Briquettes with Cassava Starch as Binder

Abstract

The evaluation of the potentials of Raphia palm seeds briquettes as fuel source was carried out to obtain optimum particle size, binder ratio and compaction pressure with cassava starch as binder for domestic heating applications. The seeds were collected, dried, hammer-milled and sieved into four different particle sizes (1.18, 1.70, 2.36 and 3.35 mm) and were densified. Four compaction pressures (2.5, 5.0, 7.5 and 10.0 MPa) and four binder ratios (15, 20, 25 and 30 %) were used. Proximate analysis of the briquettes was carried out in a bomb calorimeter and their effects on the combustion properties of the briquettes evaluated using the least significant difference (LSD) by employing two-way analysis of variance. The results revealed that the briquette with particle size 3.35 mm, binder ratio 20 % and compaction pressure 2.5 MPa gave the highest energy value of 12,785 kJ/kg, fixed carbon of 10.91 %, volatile matter of 64.30 %, ash content of 11.85 % and moisture content of 12.86 % which was the best quality briquette compared to the other samples. A predictive model for the heat value of the briquettes was developed and found to be adequate (p-value ≤ 0.0001) for use to predict the heat value of the briquettes produced. Optimization of the energy value of the briquettes was also carried to determine the optimum heat value and the probability that the result is achievable was 100 %. The optimization process gave the heat value of the briquettes to be 12,821.7 kJ/kg at the optimal condition value (24.12 % binder ratio, 1.18 % particle size and 3.00 MPa compaction pressure). The briquettes show good promise for use as fuel for household heating and small scale industrial applications.