Carbonized biomass briquette processing with various types of binders: analysis of thermo-physico-mechanical behavior
摘要
Briquettes, as a class of compacted solid biofuels, can be manufactured from several sources to serve as sustainable alternatives to fossil fuels. This research studied the effect of various types of binders -organic (walnut shell [WS] and calcium lignosulphonate [CL]), and inorganic (magnesium oxide [MgO])- on the properties of carbonized briquettes derived from biomass wastes. Cylindrical briquettes of mixing industrial/garden sawdust (50/50) and 10 wt% organic binders, without or with 2 wt% inorganic binder, were compacted at 170 °C under 150 kg/cm2 for 30 s and carbonized by indirect heating in a furnace for 10 h at 500 °C. Based on the results, briquettes containing CL exhibited significantly higher ash content compared to WS. This parameter showed a further increase when MgO was added, while the fixed carbon content reduced. Briquettes containing WS demonstrated the highest impact resistance index (IRI), without failure. Addition of MgO reduced all the mechanical strength properties of the briquettes, which was not significant for shatter index. The WS-bound briquettes demonstrated superior thermal performance to CL, which were enhanced by MgO. The efficiency of MgO in enhancing the carbonization process was confirmed by a reduction in the FTIR peak intensity, indicative of decreased organic functional groups. However, this enhanced carbonization was accompanied by a more porous microstructure, as observed in the SEM images, which adversely affected the physical and mechanical properties of briquettes.