Enhancing Biomass Gasification Performance of Palm Oil Decanter Cake using Metakaolin Additive for Sustainable Energy

Malaysia has significant potential for biomass-based energy due to its equatorial climate and extensive oil palm cultivation. The palm oil industry generates large quantities of residues, including Palm Oil Decanter Cake (PODC), which can be utilized as a feedstock for gasification to produce synthesis gas (syngas). However, the application of PODC in thermochemical conversion is limited by ash-related issues, particularly the presence of low-melting-point alkali compounds that cause slagging, fouling, and agglomeration during high-temperature processes. These challenges can reduce gasification efficiency and operational stability. This study investigates the use of kaolin, an aluminium silicate-based additive, to modify the ash chemistry of PODC and mitigate slagging behaviour. The interaction between kaolin and potassium compounds promotes the formation of high-melting-point minerals such as kalsilite and leucite, which increase ash melting temperatures and improve thermal stability. Kaolin was incorporated into PODC at different proportions of 30%, 50%, and 70% to evaluate its effectiveness in improving slagging characteristics during gasification. The results show that the blend containing 70% PODC and 30% metakaolin exhibits the most favourable performance, with higher ash fusion temperatures and reduced slagging tendency as confirmed by Ash Fusion Temperature (AFT) and X-ray Diffraction (XRD) analyses. FESEM observations revealed a more porous ash structure with reduced cohesive bonding, which minimizes ash agglomeration. Gas Chromatography (GC) analysis also indicated improved syngas quality during gasification. These findings demonstrate that kaolin-assisted ash modification can enhance the gasification performance of PODC, supporting sustainable biomass energy utilization.