The Preparation And Application Of Solid Base Catalyst In The Productionof Biodiesel By Waste Animal Fat

There is a large stock of waste animal oil in Shenzhen municipal waste disposal center, and it will cause great harm to the health of people if the waste animal oil is reprocessed into cooking oil by unlawful peddlers. However, the waste animal oil prepared into biodiesel has the advantages of environmental protection and renewable. This is the way to turn waste into treasure. The raw oil used in this research is the low acid value oil which comes from the pretreatment process of waste animal oil with acid catalysis. The purpose of this project is to develop an industrial class solid base catalyst with strong alkaline to ac hieve base-catalyzed transesterification reaction referred to produce biodiesel with waste animal oil. The optimal reaction conditions of base-catalyzed process were also investigated.With the comparison of four kinds of solid base catalyst s, Na Al O2/Al2O3, Na Al O2/C, Na Al O2/Si O2 and Na Al O2/bentonite in catalytic activity and repeatability of base-catalyzed transesterification reaction, the Na Al O2/Al2O3 was selected as a subsequent research solid base catalyst in this projected for its best performance. In order to study the catalytic properties of the catalyst Na Al O2/Al2O3, the alkali density was determinate, and it also was investigated with SEM, BET, ICP, XRD methods. Test results show that the lamellar structure of catalyst is assembled together by a blocky-shaped particle. The crystallization of Na Al O2 is complete, while the crystallization of Al2O3 is incomplete. Besides, surface alkali density of Na Al O2 is 7.167 mmol/g and specific surface area is 20.11 m2/g. Therefore, the Na Al O2/Al2O3 solid base catalyst has higher catalytic efficiency which could reach 95.2%.Simultaneously, the optimization conditions of base-catalyzed transesterification reaction of Na Al O2/Al2O3 solid base catalyst are obtained as follows: the reaction time is 30 min; the reaction temperature is 60 ℃; the mass ratio of alcohol to oil is 7:1 and the dosage of catalyst is 10%. Moreover, the esterification efficiency can reach 95.8%. The catalytic activity could remain 92% through the batch added method. In the process of preparation biodiesel with waste animal oil by two-step method, the biodiesel yield was up to 68%. It shows the high efficiency of waste recycling. Finally, the properties of biodiesel were determined with standard methods, and the results indicted that preparation biodiesel met the relevant standards.