Abstract:
Converting biomass wastes into high density and energy concentrated fuel briquettes is one of the
alternative ways to overcome the undesirable characteristics of utilizing biomass in its original
forms. However, the quality of briquettes is influenced by several factors, including the types of
feedstocks used. This study aimed to evaluate the quality of briquettes made from coffee byproducts
and municipal solid wastes. The briquettes’ fixed carbon, moisture content, volatile matter, ash
content, sulfur content, bulk density, and calorific values were analyzed following the ASTM Dstandards at geochemical laboratory of Geological Institute of Ethiopia. The moisture content was
determined by drying the samples in an oven at 105°C for 24 hours. The volatile matter was
determined by heating the samples in a furnace at 950°C for 6 minutes. The fixed carbon was
calculated by subtracting the moisture content, volatile matter, and ash content from 100%. The
ash content was determined by burning the samples in a muffle furnace at 750°C for 3 hours. The
sulfur content was determined using the Adiabatic Oxygen Bomb calorimeter. The bulk density
was determined by measuring the mass and volume of the briquettes. The calorific value was
determined using a bomb calorimeter. The results for briquettes made from coffee byproducts and
its mixture revealed that, a 20% higher composition of coffee pulp than husk (T2), and a 100%
coffee pulp (T1) had higher calorific value of 4490.5cal/g and 4484.6cal/g, respectively. Lower
moisture content was found in briquettes from a 100% coffee husk (T4) with 4.51% and a 20%
higher composition of coffee husk than pulp (T5) with 4.79%. Test results on volatile matter, ash,
fixed carbon and sulfur content showed, T4 had the lower with 30.39%, 9.89%, 53.68% and 0.07%,
respectively. Moreover, T1 had higher density with 0.77g/cc. In addition, the results for briquettes
made from Municipal solid wastes (MSWs) and its mixture revealed that, briquettes made from a
100% sugarcane bagasse (T6), and a 20% higher component of sugarcane waste than Khat (T10),
had higher calorific value of 3663.1cal/g and 3643.4cal/g, respectively. In moisture content test,
T6 briquettes had higher with 5.9%. Test results on volatile matter, fixed carbon and bulk density
showed, T9 (briquettes made from 60% khat and 40% sugarcane wastes) had the lower with
59.68%, 46.6% and 0.56g/cc, respectively. Moreover, T6 had a relatively lower ash and sulfur
content with 11.32% and 0.03%, respectively. Overall results showed that, briquettes made from
coffee pulp and mixing it with lower amount of coffee husk had best fuel properties among other
coffee waste briquettes. Similarly, briquettes from sugarcane bagasse and mixing it with lower
amount of Khat waste had best fuel properties among other briquettes made from MSWs in this
study
