Application of Torrefaction for Production of Quality Briquette from Sugar cane leaves and Top Composite

Abstract

Every year millions of tons of agricultural residual biomass are generated worldwide which are either destroyed or burnt inef iciently in loose form causing air pollution. Among those residues sugar cane biomass, especially the dry leaves and tops of the sugarcane produced during harvesting of sugar cane is the major one. On other hand, there is high consumption of fire wood and charcoal that is causing the degradation of the limited forest resource. Therefore, the objectives of this study was to recover sugar cane dry leaves and tops composite as alternative source of energy by improving its characteristics through proper pretreatment technique like torrefaction and converting biomass waste into high density fuel briquettes. Sugarcane dry leaves and top composite with the ratio(60:40) in dry weight bases were Torrefied at a temperature (230 oC,260 oC, and 290 oC),curing time (30 & 60 min) and particle size (2 mm,4 mm ,and 6 mm). Briquetting of selected torrefied sample were done at briquetting pressure of (8, 10, and 12Mpa), die length (40, 50, and 60mm) and holding time (3, 5, and 7min) to elevate its character as a solid fuel. The produced briquette was then checked for bulk density, shattering resistance and HHV values to assess its quality. The optimum pretreatment value that yield maximum calorific value of 20.03 MJ/Kg compared to the raw composite (17.07MJ/kg) was found to be particle size 2mm and torrefaction temperature of 290 oC and dwelling time of 60 minute. The optimum briquetting process variables were 50 mm die length, a pressure 12 Mpa and a dwelling time of 7 min. The produced briquettes had bulk density (0.89g/cm3), scattering resistance (99.83%), and HHV (22.04 MJ/Kg). Therefore, from the obtained result, thermal pretreatment /torrefaction/ of sugarcane dry leaves and top composite with composition (60:40 in dry weight bases) significantly improve the energy values and properties of leaves and tops that lead to the formation of quality briquette that can be used as alternatives