Study On Biodiesel Synthesis From WCO By Heterogeneous Catalyst

Biodiesel has received more and more attention because it has renewable andenvironment-friendly advantages. Although biodiesel has been commercialized inmany countries, the cost of biodiesel is still high in China. The identified limitationsin the commercialization of biodiesel production are its complex materials and thehigh manufacturing cost. In this study, biodiesel was made from waste cooking oil(WCO) in a simple continuous fixed bed reactor of biodiesel by solid acid catalyst.In this study, the properties of WCO were investigated first. The results were: thecontent of (free fatty acids) FFA was57.4%, the acid value was108.819mg/g and thecontent of moisture and volatile matter was1.19%. That means this material is notsuitable for alkali biodiesel. The content and distribution of the free fatty acids in theWCO were also analyzed and from the results we could speculate this material couldproduce qualified biodiesel. Then NKC-9ion-exchange resin and H-beta zeolite wereselected as heterogeneous catalyst and their esterification characteristics have beencompared. NKC-9resin showed higher activity and achieved a higher finalconversion compared with H-beta zeolite in the same reaction conditions. And theconversion reached67%at the optimized reaction conditions (reaction temperature of80℃, molar ratio of3:1, the catalyst amount of15wt%and reaction time of6h) byorthogonal experiment. And from the reusability experiments it can be found thatH-beta has better stability while NKC-9resin still has higher activity (57.4%) after5runs. The study also investigated the effect of FFA content in the oil on theesterification conversion by NKC-9resin. The result shows that the conversiondecreased with the increase in FFA content. And the conversion rate (36.2%) is thelowest with the FFA content of71.3%.Based on the results above, a simple continuous fixed bed reactor（Ф30600mm）of biodiesel was set up, which put the NKC-9ion-exchange resin into thefixed bed reactor as catalyst. It has been found that the FFA conversion decreasedwith the increase of the flow rate. The change of FFA conversion with alcohol/oilmass ratio and the bed height was also investigated. The FFA conversion increasedwith an increase in the mass ratio of alcohol to oil and the bed height. The conversion reach50.1%with the catalyst bed height is600mm when the flow rate is10.6mL/min. In this case, the FFA content decreased to3.15%and this study provided atheoretical foundation and experimental reference for industrial production.