Thermal Degradation Conditions Effects on Selected Biomass Wastes and Characterization of Their Produced Biochar

Abstract

Biochar has been proved to be effective in soil amelioration applications, carbon sequestration and also reduce GHG emissions which causes global warming. Biomass stands a greater chance of prevailing as a good source for the production of biochar, which in turn can be a solution for waste management. However, pyrolysis conditions for biochar production, together with feedstock characteristics largely control the physical and chemical properties of the yield biochar product. In this study, investigation on thermal degradation conditions effects on biochar production is carried out. Bio-char was produced using 35.3 litres fixed bed reactor from pyrolysis of Corn Cob (CC), Palm Kernel Shell (PKS) and Sugarcane Bagasse (SB) at temperatures ranging from 100°C to 500°C. The feedstock was also blended in ratio to each other and pyrolyzed to 250°C and 400°C. The analyzed results showed that higher pyrolysis temperatures resulted in lower bio-char mass recovery, higher ash contents, decreased fixed carbon and moisture content. Product characterization also showed that the produced biochar, independent of biomass waste type contained negligible amount of Sulphur (S) and Nitrogen which resulted in lower emission of SO2 and NO2 during the combustion process, this behaviour is observed to be more pronounced with the blended biochar samples investigated in this study as a result, the obtained bio-char product can be used directly for heating purposes. ANOVA test results for both volatile matter and Ash content of the produced biochar revealed that the P-value is greater than 0.01 independent of the biochar samples considered whereas for the fixed carbon of the same bio-char samples, P-value less than 0.01 is attained. These results show how control of biomass pyrolysis conditions can improve biochar chemical properties consequently biochar produced from biomass wastes could be a suitable candidate for alternative energy fuels in terms of quality and environment concern.