Development of composite briquettes using cassava rhizomes and groundnut stalks for domestic cooking

Abstract

Overdependence on firewood and charcoal for domestic cooking has led to deforestation, air pollution, and respiratory diseases such as asthma. Therefore, this study aimed to develop and characterize briquettes made from cassava rhizomes and groundnut stalks with jackfruit waste binder as an alternative fuel for domestic cooking. The objectives were to characterize the feedstocks, assess and optimize briquetting parameters, and determine the briquettes' physical, thermal, and mechanical properties. A thermogravimetric analyzer and a bomb calorimeter were used to determine the physical properties and calorific value of feedstocks and briquettes, respectively. Parkish and Shen’s models were used to determine the elemental composition of feedstocks. A Box Behnken design was used to develop the design of the experiment and optimization of factors (blending ratio, binder amount, and amount of water) to determine the optimum briquetting parameters that could lead to briquettes with maximum mechanical and thermal properties. The combustion efficiency tests that were conducted include the water boiling test, ignition test, burning rate, and specific fuel consumption. Calorific values and drop strength of briquettes ranged from 18.073 MJ/kg to 24.0157 MJ/kg and92% to 99%, respectively. The optimum biochar blending ratio, amount of water, and binder amount were found to be 89.33%, 893.00 ml, and 29.53%, respectively. The study concluded that carbonization of the feedstocks improved the calorific value of briquettes if compared to raw feedstocks that had a heating value between 12 MJ/kg and 16 MJ/kg. This research has provided insight and positivity the utilization of cassava rhizomes and groundnut stalks with jackfruit waste as a binder in the development of briquettes as an alternative fuel for domestic cookingas affirmed with FVI between 393.432 –622.765 GJ/kg that is above the minimal conservative value of 100. However, there is a need for further studies to be done on the techno-economic and environmental analysis on the production of these briquettes.