The Utilization Of Heterogeneous Base Catalyst For Biodiesel Production And Its Life Cycle Assessment

Due to the limited oil reserves and the increasing associated environmental issues,Renewable energy has gained extensive attention.Compared with diesel,biodiesel is regarded as an alternative fuel,which has several merits such as renewability,biodegradability and it can be used directly in engines without any modification.Previously,the homogeneous bases were preferred for transesterification reaction on a commercially scale because of high-activity.Unfortunately,homogeneous bases proved to be sensitive to free fatty acids and water resulting in saponification,which have a negative effect on the performance of the catalyst.In contrast,heterogeneous bases have been found to be easily separated from reaction mixture,thereby simplifying the production process,leading to their global employment in biodiesel production.Besides,development of biodiesel is a whole system engineering.To make the right decisions and provide theory support for the commercial application of biodiesel production,it is necessary for researchers to analyze the life cycle impact on biodiesel production process which including every stage from planting to utilization for assessing its energy and environment value.So the preparation,activity and stability of solid waste derived supported catalyst CaO-Ce O₂/HAP were discussed in this study.Also,the environmental load assessment was conducted based on theory of LCA.Calcined waste bone derived hydroxyapatite?HAP?was served as the support for CaO-CeO₂/HAP catalyst.More specifically,the CaO-CeO₂/HAP catalyst showed comparable catalytic activity to the CaO-CeO₂ catalyst.Compared with calcined bone catalyst,the activity and stability of synthetic catalyst were preferred due to the interaction of Ca ion and Ce ion,which was regarded as a low-cost catalyst along with high activity and stability.As shown in our study,the optimal active component loading and calcination temperature were 30 wt.%and 650 ^oC,respectively.Under the optimal reaction conditions?11 wt.%dosage of 30%CaO-CeO₂/HAP-650 catalyst and9:1 methanol to oil molar ratio at 65 ^oC for 3 h?the highest biodiesel yield of 91.84%was obtained.Stability test indicated that the yield?84.4%?of fatty acid methyl ester was produced after 8 re-used cycles due to the low leaching of catalyst components.Based on the synthetic catalyst and optimal prepared condition,the life cycle assessment of biodiesel production from palm oil was conducted combined with theory of LCA.The result indicated that the environmental load single score was0.00307 Pt in the whole processes.The transesterification reaction stage played the major role whereas the transport stage played the least role.The environmental comparison between Na OH and CaO-CeO₂/HAP catalysts indicated the Ozone layer depletion CaO-CeO₂/HAP catalyst was lower than NaOH catalyst.Considered the twice reaction cycle of CaO-CeO₂/HAP catalyst,the comparable environmental loads were obtained.So stability of heterogeneous bases would contribute to positive environment effect,thereby having great significance for environmental load reduction of biodiesel production.