Study On Waste Oil Extraction-solid Base Catalyst Transesterification For Biodiesel Production

Biodiesel,as a kind of good substitute for petroleum diesel,have many advantageous properties.Waste cooking oil as raw material for biodiesel has attracted a lot of attention in recent years.At present,esterification-homogeneous transesterification method of waste oil for biodiesel is widely used,the method has many disadvantages,such as,complex reaction process,improper operating conditions,large energy consumption in production,difficult products separation,intending to cause equipment corrosion and environmental harm,et al.In order to improve the original process methods,the method of physical extraction to reduce acid value-solid base catalyst transesterification for producing biodiesel was developed in the paper.First,the liquid-liquid phase equilibrium of triglycerides-oleic acid-methanol ternary system and partition coefficients were studied in the process of waste oil extraction and the critical condition of extraction is obtained,simulating the liquid-liquid phase equilibrium of ternary system at different line speeds,which can provide a good correlation between the simulated results and the experimental results,confirming the feasibility of waste oil extraction to reduce acid value.Secondly,the solid base catalyst transesterification for biodiesel was studied,obtaining the better preparation condition.It indicates that the catalyst has a strong catalytic activity and stability based on the results of the physical and chemical properties of solid base catalyst.Effects of the reaction temperature,reaction WHSV,molar ratio of methanol to oil on transesterification were studied for transesterification in fixed bed.The oil conversion could reach 99.42%under the optimum conditions of temperature 333.15K,WHSV 0.25h^-1,molar ratio of methanol to oil 11:1,.The results of industrial pilot test showed that the methods of physical extraction to reduce acid value-solid base transesterification method for producing biodiesel have a certain industrial feasibility and advancement,which has many advantages,simple process,moderate operating conditions,etc.The kinetics model for transesterification in fixed bed is built to explains the mechanism of transesterification,this provides guidance for the industrial production.