Can waste eggshell replace commercial zeolites as catalyst for bio-oil production?

Abstract

The utilisation of calcium oxide (CaO) from waste chicken eggshells, fishbone, and dolomite as a catalyst in the co-pyrolysis of empty fruit bunch (EFB) and high-density polyethene plastic (HDPE) was investigated and compared with existing commercial zeolite catalysts (HZSM-5, NaY, and FCC). In-situ catalytic co-pyrolysis of EFB-HDPE was performed for each CaO and zeolite-based catalyst. Gas Chromatography-Mass Spectrometry (GC-MS) was used to analyse the hydrocarbon content of the bio-oil produced by pyrolysis. The highest hydrocarbon content (61.62%) was obtained from the calcined eggshell (CES) catalyst and was comparable to that of the commercial zeolite catalyst, HZSM-5, with a hydrocarbon content of 53.53%. Brunauer–Emmett–Teller (BET) analysis, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX) analysis, and Particle Size Analysis (PSA) have proven the viability of CaO-based catalysts in the co-pyrolysis process for bio-oil production via fast pyrolysis. The CES achieved the desired pore diameter (175.15 nm) which was exhibited in the morphology analysis (SEM) and exhibited a uniform arrangement of calcium oxide particles and a porous structure. This finding provides fundamental insight into CaO from organic waste as a suitable alternative to zeolite catalysts in the co-pyrolysis of organic and inorganic feedstocks.