Comparative Analysis of Catalyst Efficiency in Biodiesel Production from Waste Oils

Thesis Abstract

The increasing global demand for sustainable energy sources has heightened interest in biodiesel production from waste oils, which presents a viable avenue for reducing environmental pollution and dependence on fossil fuels. However, the efficiency of catalysts used in transesterification processes remains a critical determinant of biodiesel yield, quality, and economic viability. Despite extensive research, comparative evaluations of different catalyst types—homogeneous alkaline, heterogeneous alkaline, and heterogeneous acid catalysts—are limited, particularly in the context of waste oils with varying compositions. This study aims to conduct a comprehensive comparative analysis of catalyst efficiency in biodiesel production from waste frying oils, with the specific objectives of (1) assessing the biodiesel yields obtained from each catalyst type, (2) evaluating the conversion efficiencies and physicochemical properties of the produced biodiesel, (3) analyzing the energy consumption and cost implications associated with each catalyst, and (4) establishing correlations between catalyst properties and biodiesel quality parameters. The research adopts an experimental research design, utilizing a quantitative approach to systematically compare the performance of selected catalysts. The study population comprises waste frying oils collected from local restaurants, with a total sample size of 150 samples randomly selected and characterized for fatty acid profile and moisture content. The catalysts evaluated include sodium hydroxide (homogeneous alkaline), calcium oxide (heterogeneous alkaline), and sulfonated carbon catalyst (heterogeneous acid). Data collection involves standardized laboratory procedures for catalyst preparation, transesterification, and biodiesel purification, with Fourier Transform Infrared Spectroscopy (FTIR), Gas Chromatography-Mass Spectrometry (GC-MS), and Thermogravimetric Analysis (TGA) employed to analyze biodiesel composition and quality. Catalyst activity and efficiency are measured through yield percentage, conversion rate, and physicochemical parameters such as viscosity, acid value, and free glycerol content. Data analysis incorporates descriptive statistics to summarize yields and quality parameters, while inferential techniques including Analysis of Variance (ANOVA) and regression analysis are employed to compare catalyst performances and identify significant predictors of biodiesel quality. The analytical framework further includes the application of the Theory of Catalysis Efficiency and the Waste-to-Energy Conversion Model to interpret the relationships among catalyst properties, process parameters, and biodiesel outcomes. The study anticipates discovering notable differences in catalyst efficiency, with heterogeneous catalysts potentially offering advantages in catalyst recovery and reusability, thus influencing economic assessments. It is expected that the findings will reveal statistically significant variations in biodiesel yield and quality across different catalysts, with specific physicochemical parameters aligning closely with catalyst type and operational conditions. This research contributes to the existing body of knowledge by providing a detailed, empirically validated comparison of catalyst performance in biodiesel production from waste oils, thereby informing best practices and optimizing process parameters for industrial application. It enhances understanding of the catalytic mechanisms involved in transesterification processes, particularly for feedstocks with complex fatty acid compositions. The study also offers insights into the economic and environmental implications of various catalysts, emphasizing sustainability and resource efficiency. The main conclusion underscores the suitability of selective heterogeneous catalysts for scalable biodiesel production, recommending the integration of these catalysts in commercial biodiesel plants to improve yield, reduce process costs, and promote environmental sustainability. Future research should explore catalyst regeneration and long-term stability to further refine catalyst selection criteria for waste oil-based biodiesel production systems.