| It is indispensable of fossil diesel to our daily life, its non-renewable has decided it will become increasingly scarce, final depletion. But,, Human demand for it increasing and there is a series of environmental questions begeted by fossil diesel burning, so human have to explore and seek a kind of renewable and environment-friendly enery to take the place of fossil diesel. At the same time, bodiesel was born.Transesterification is one of the most commonly method which is used to produce biodiesel, and Homogeneous catalysis he most widely method in the transesterification. But Homogeneous catalysis have a lot of shortcoming, such as, is different to be separated from product, and It easily to erode the equipment. In recent years, the more and more kinds of catalyst are used in the transesterification for biodiesel preparation (Solid acid-base method, enzymatic method, the supercritical method, whole-cell biologically, and so on). All of them have both advantages and disadvantages.WO3-ZrO2(WZ) is a kind of Super solid acid, which is one of the most representative solid acid. On the other hand, as an environmentally friendly renewable fuel, biodiesel play an significance role to solve the problems caused by oil shortages and petroleum diesel. For the biodiesel preparation, Solid acid catalyst is not only affected slightly by the water of raw material and free fatty acid, but also not cause corrosion damage to the equipment, and easy to recycled and separated。 So WO3-ZrO2(WZ) used as catalyst for the preparation of biodiesel, is important to solve the fuel crisis and environmental problem.There are two parts in this work:(1)The preparation of Nanometer mesoporous WO3-ZrO2. It was characterized by the by means of small angle XRD, N2desorption-adsorption, NH3-TPD, SEM, TEM, EDS and so on. It was investigated that the effect of different W loading、calcination temperature、 different templates on WO3-ZrO2. The results showe that, The BET, pore size, acidity, crystal phase of WZ change with the calcination temperature, and the reasonable WZ got at the follow condition:calcination temperature=550℃, W loading=30%, CTAB used as template, and the property of WZ show as follow:surface area is up to175m2/g with the average pore diameter of4.11nm, pore volume of0.180cm3/g, and particle size of6nm。Its total amount of acid is4329.6site/g, acid density is21.32site/m2。(2)The study of WZ catalyzed the transesterification between soybean oil and methanol. both single-factor experiments and response surface optimization experiment are designed in this work, and the best reaction parameters was determined:Methanol to oil molar ratio of20:1,reaction temperature of180℃, the catalyst amount of6%, reaction for10h,30%of WO3-ZrO2W loaded, the catalyst calcinatied at the temperature of550℃, at this reaction: the yield of FAME was up to81.5%. WZ’s recycling activity was also assessed in this work, and it found that the catalytic activity of WZ just has a slight decrease after using5times. |
PDF Full Text Request