Briquettes from Fruit Waste

Published: 11 July 2023| Version 1 | DOI: 10.17632/56mr27xz8y.1


This work aimed at developing and characterizing briquettes from orange, mango, and jackfruit wastes at Soroti Fruits Limited and Jakana Foods Limited in Uganda. The briquette development process used cassava starch, cornstarch, and clay as binders, and a manual lever press for compaction. Physical and chemical properties were examined for both homogeneous and composite briquettes at varying binder concentrations. Moisture content, volatile matter, fixed carbon, and ash content were examined using thermogravimetric analysis through an Eltra thermostep thermogravimetric analyzer, software version TGA1.4.3.2a3, with an accuracy of ±0.0001 g. Calorific values of the developed briquettes were determined with bomb calorimetry using an IKA C 2000 oxygen bomb calorimeter with an accuracy of ±0.01 ℃. Mechanical integrity was examined through drop strength, bulk density, and compressive strength. Water boiling tests were also conducted using the water boiling test protocol 4.2.3. Thermogravimetric analysis showed that the developed briquettes had good physical properties. The 26.71% average volatile matter content indicated that the briquettes were easy to ignite, and they released low emissions during combustion. Briquettes which entailed mango fruit waste char had higher fixed carbon and subsequently registered higher calorific values. Briquettes with starch binders had lower ash content compared to briquettes with the clay binder. The highest rate of change in the burning rate was registered between the 100th and the 135th minutes. The lowest and highest percentage weight losses at the highest combustion temperature were 56% and 78%, respectively. Although briquettes with the cassava starch binder had higher compressive strength compared with cornstarch and clay binders, the 0.271 N/mm2 average compressive strength for all developed briquettes was lower than 0.38 N/mm2, the acceptable compressive strength in the industry. The low mechanical integrity was further confirmed by a 51% average drop strength which means that the developed briquettes are susceptible to damage during transportation and storage. The low mechanical integrity in this study highlighted the short comings of using a manual lever press as a compaction method. Water boiling test results re-echoed the optimum calorific value and volatile matter content results from briquettes which had starch binders. The results show that briquettes with fast ignition and the ability to release more energy shorten the cooking durations.



Makerere University


Bioenergy, Biomaterials Characterization, Agricultural Waste