Combustion Test of Densified Arabica Coffee Pulp Biochar in a Purposely Built Chamber

The study of solid fuel combustion characteristics is still continuing due to increases in demand of clean and renewable source of energy. Agricultural waste such as coffee pulp is an alternative source of biomass which has not optimally been utilized. The aim of this study is to examine the characteristics of the solid fuel combustion of densified coffee pulp biochar in a purposely built furnace. Initially, a simple mechanical design of combustion test furnace was prepared equipped with data logger for measuring weight lost and temperature changes. As main testing fuel, arabica coffee pulp was pyrolyzed and densified by adding starch binder. For comparison, locally available commercial coconut briquette and young brown coal were also tested under similar condition. The weight of each fuel sample was ≤ 50 g. Based on combustion test results, required time for ignition of coffee pulp and coconut briquettes was 2 min, and it took 5 min for coal. The combustion rate of densified coffee pulp biochar, coconut briquette, and coal was 0.5 g/min, 0.59 g/min, and 0.23 g/min, respectively. The maximum combustion temperature of 480 °C at 35 min, 375.9 °C at 45 min, and 487 °C coal at 140 min was observed during the combustion test of densified coffee pulp biochar, coconut briquette, and coal, respectively.