OP-II-3

OP-III-A-1materials with other shapes of opportune size we can increase the local micromixingand consequently the activity and yields.First of all, in this work the fluid dynamic behavior of a tubular reactor, simplyfilled with stainless steel balls of uniform size, has been examined with a step test.This tubular reactor has a length of 20 cm, an internal diameter of 1 cm, an emptyvolume of 15.7 cm 3 , a void volume after the filling of 6.8 cm 3 and contained about2000 spheres of 2.5 mm of diameter. From this preliminary study we have concludedthat the reactor is locally well mixed for relatively low flow rates above 5.6 cm 3 /minutecorresponding to a Reynolds Number of 2.17 and a Peclet of 30. Differenttransesterification kinetic runs have then been performed on soybean oil withmethanol, in the presence of KOH catalyst, for different overall flow rates of thereagents that have been kept at constant molar ratio. Flow rates were changed from0.73 to 12.3 cm 3 /minute respectively corresponding to 15.07-0.89 minutes ofresidence time. It is interesting to observe that the achieved yields in biodieselincreased by decreasing theresidence time till to reach amaximum value incorrespondence to a residencetime of 1.59 minutes (see thefigure), then we observe adecrease, as expected whenthe chemical regime iscompletely attained.The work proceeds by considering what happens when the cavities between thespherical balls of 2.5 mm of diameters are filled with smaller balls of 0.39 mm. In thiscase, microchannels of about 300 µm are formed and the described device operateslike a microreactor, but the kinetic approach can be assimilated to that of a plug flowtubular reactor. At last, filling material of different shape and size more suitable thanspheres to induce local micromixing will be tested on the same reaction. Anotherobjective of this work is to ascertain the intrinsic kinetics of the transesterificationreaction, because, the operative conditions can be chosen in such a way to eliminatemass transfer limitation.References[1]. E. Santacesaria, M. Di Serio, R. Tesser; Italian Patent Na2009A000024, 2009 Assigned toEUROCHEM Engineering.[2]. E. Santacesaria, M. Di Serio, R. Tesser, L. Casale, D. Verde, R. Turco, A. Bertola; Energy Fuels2009, 23, 5206–5212.[3]. E. Santacesaria, M. Di Serio, R. Tesser, R.; R. Turco, D. Verde, L. Casale, Italian PatentI2008A002302, Dec. 2008 assigned to MYTHEN SpA Co.154