Kinetic Study of Waste-derived Solid Hydroxy Sodalite Catalyst during Transesterification of Animal Fat Oil to Biodiesel in a Batch Reactor

Abstract

Abstract Kinetic studies of heterogeneous catalytic reactions form a crucial step necessary for the understanding of catalytic behaviour of a catalyst towards designing, controlling and optimizing a reactor. This study reports kinetics of waste animal fat oil (AFO) transesterification to biodiesel using waste-derived heterogeneous catalyst, hydroxy sodalite (HSOD) in a batch reactor. The catalyst was synthesized from coal fly ash and waste industrial brine via hydrothermal treatment. At a temperature range of 49 - 62 °C and a time range of 30 -120 minutes, the transesterification of animal fat oil to biodiesel was conducted at a fixed methanol/oil mass proportion 9:1, percent mass weight of catalyst 3 (based on the AFO) and stirring intensity of 300-500 rpm. Experimental findings reveal that reaction rate, which is first-order, was anticipated to increase with increasing temperature, resulted in an activation energy and a pre-exponential factor of 58554.65 J mol-1 and 2.83 min-1, respectively. The value of the activation energy suggests that the reaction is endothermic and a minimum energy of 58.55 kJ is required to achieve an effective collision at a frequency of 2.83 min-1. The highest biodiesel yield was 90 % at 62 °C and this corresponds to a highest AFO conversion of 93 % at a reaction time of 120 minutes.