The Effects of Jatropha curcas and Ricinus communis Seeds Addition on Coffee Pulp Waste Pellets as Fuel

The present study aimed to analyze the effect of the addition of Ricinus communis and Jatropha curcas seeds in two mass percentages (10 and 30%) in coffee pulp waste feedstocks on the physical, chemical, and energetic properties, compressive strength, and durability. The results showed that the high ash content, low apparent density, and higher heating value (HHV) were biomass characteristics that limit pulp coffee for the thermochemical process. However, the mixing of J. curcas and R. communis seed with the coffee pulp improved the energy characteristics of pulp coffee pellets. The HHV was 16.79 MJ/kg for pellet fabricated with 100% of coffee pulp, but if the pellets were fabricated with 30% of oilseed, the HHV increased to 19.55 MJ/kg. The ash was not affected by the oilseed usage and the moisture content decreased from 12% for coffee pulp pellets to 8% with oilseed usage. The moisture absorption decreased too when the pellets were fabricated with the mixing between the coffee pulp waste and oilseed. The disadvantage of pellets’ fabrication with seed oil was that the bulk density, apparent density, compressive strength, and mechanical durability of the pellets were reduced. Graphical Abstract: [Figure not available: see fulltext.].