Effect of Pyrolysis Temperature and Time on Properties of Palm Kernel Shell-Based Biochar

Abstract

Pyrolysis is a thermal decomposition of biomass occurring in the absence of oxygen. Biochar (solid), bio-oil (liquid) and biogas (gas) are the typical products from pyrolysis of biomass. This endothermic process produced biochar with high carbon content. During pyrolysis, the material is heated up from ambient to a peak temperature and remains for a defined residence time. Therefore, the pyrolysis peak temperature and the residence time are the key parameters for pyrolysis. Studies on the effect of these parameters on the biochar characteristics and the pyrolysis products composition are numerous. However, there are limited findings of these parameters with palm kernel shell (PKS) as the biomass. This study focusses on the effect of the pyrolysis temperature and residence time of PKS on the yield of biochar produced and the biochar physio-chemical properties. The results showed that biochar yield decreased as the peak temperature and residence time increased. This finding is consistent with the findings by other researchers. However, those factors do not have distinct influence on biochar's carbon content as found in other study which the peak temperature has the bigger impact instead of residence time. The effect of peak temperature or residence time on grindability; i.e. particle size of biochar after wet ball milled is insignificant. Smaller size of biochar may improve its function as reinforcing filler. As a conclusion, the optimum setup of pyrolysis is needed for a balance production in yield and biochar's properties. It is recommended to produce biochar at higher peak temperature and shorter residence time to increase the total production. Additional analysis e.g. physical testing on the final polymer product can be used to investigate the effect of pyrolysis peak temperature and residence time.