Fine-tuned fabrication parameters of CaO catalyst pellets for transesterification of palm oil to biodiesel

Abstract

In recent years, the use of heterogeneous catalysts has gained increasing attention for biodiesel production. Among metal oxide catalysts, CaO powder is widely explored and considered to be a promising catalyst. However, the powder catalyst is inappropriate for continuous biodiesel production. Therefore, the catalyst pellet fabrication parameters related to its properties and biodiesel yield were investigated. Key results included the observation that catalysts produced using an Al2O3 binder possessed the highest catalytic activity compared to kaolin and diatomite supported catalysts, for calcination temperatures of 800 °C, possessing a comparable catalytic activity to the CaO powder. The CaO to Al2O3 mass ratio exhibited a significant effect on the surface area and total basicity. The highest biodiesel yield was obtained using the CaO-A(800)-3.5:1 catalyst due to the presence of several active crystal phases including CaO, Ca(OH)2 and CaSiO3 phases to accelerate the transesterification rate. These fabricated CaO catalyst pellets can be utilized as a catalyst for the continuous biodiesel production process.