traduccion

INEXPENSIVE AND SIMPLE
BINARY MOLECULAR DIFFUSION
EXPERIMENTS

KYUNG C. KWON, TALEB H. IBRAHIM, YOONKOOK. PARK, CHRISTY M. Sirvn Tuskegee University • Tuskegee, AL 36088
Tree chemical engineering laboratory classes are taught at Tuskegee University: one for junior students and two for senior students. The Junior Unit Operations laboratory class consists mainly of fluid-mechanics and heattransfer experiments. The Senior Unit Operations labo­ratory class consists mainly of mass transfer, thermodynam­ics, and chemical-reaction experiments. The third laboratory consists of, process-control experiments.
The senior laboratory course was designed for students to obtain experimental data by conducting. various experiments through laboratory-scale unit operations, to statisticallyinterpret these data, to write technical reports on the basis of statistical interpretations of experimental data, and to design a flow reactor, a distillation column, and a fluidizedbed de­ contamination vessel under the desired operating conditions. Final composite grades were based on laboratory reports, design reports, final examinations, and attendance.
We added a binary molecular diffusionexperiment to the senior laboratory course to improve its course contents and to satisfy ABET 2000 criteria. The experiment was designed as an extension of the mass transfer course and the transport phenomena course (offered to seniors) and the engineering mathematics course (offered to juniors). Acetone and methylene chloride. in addition to n-heptane. were used for the diffusion experiment. The firstchoice fol• the diffusion experiment was n-heptane since it is almost odorless and is less toxic and stabler than the others. The objectives of this experiment were for our students to design and conduct the diffusion experiment, to analyze and interpret diffusion experimental data by applying knowledge of mathematics and science to diffusion experimental data, and to write laboratory reports withcomputer software.
Setup of an experimental apparatus is simple and inexpen
sive, since only an electronic balance and a test-tube are needed as the major equipment. The binary molecular diffusion experiment provides an opportunity for students to apply mathematical and computational skills to analyzing statistically experimental data and to write a report using computer software. The experimentalso familiarizes students with the concept of mass transfer, which they learned in the mass transfer and transport phenomena courses.
Binary diffusion coefficients of vapors of liquids diffused into stagnant air are determined at room temperature and atmospheric pressure. Experimental data on binary diffusion coefficients are obtained from the steady-state open tube evaporation Method modifiedfor this study. Experimental binary diffusion coefficients are obtained by applying experimental dam of mass loss of volatile liquids vs. evaporation duration to the developed diffusion equation'. Predicted binary diffusion coefficients are calculated with the WilkeLee method and compared with experimental values obtained from this study.
Kwon is professor of Chemical Engineering at TuskegeeUniver­sity. He received his BS from Hanyang University his MS from the University of Denver; and his PhD from Colorado School of Mines. His research interests include reaction kinetics, coal conversion, adsorp­tion separation, metal oxide sorbents, and transport properties.
T.H. Ibrahim is Assistant Professor at American University of Sharjah, UAE. He received his BS from Tuskegee University, his MSfrom Tuskegee University and Auburn University, and his PhD from Auburn University. His research interests include interfacial phenomena/sur­face, colloidal science, and material science.
YoonKook Park is Assistant Professor at Tuskegee University. He re­ceived his Phi) in chemical engineering from Auburn University in 2000. After a postdoctoral fellow at the same university, he joined the...