Mass transfer phenomena are common in nature and important in all branches of the engineering. Some examples within the industrial processes are: the removal of polluting materials from the discharge currents of gases and contaminated water, the neutron diffusion inside nuclear reactors, the diffusion of substances to the interior of activated carbon pores, the speed of biological and chemical catalyzed reactions, etc.
The molecular diffusion (or molecular transport) is a mass transfer mode that can be defined as the transfer (or displacement) of individual molecules through a fluid by the disorganized and individual displacements of the molecules, due to concentration differences. Diffusion may take place in stagnant fluids systems or in fluids in motion.
The Computer Controlled Gaseous Mass Transfer and Diffusion Coefficient Unit, "QDTGC", allows the students to familiarize with the theoretical concepts about mass transfer unit operations, specifically the diffusion of a volatile liquid in an inert gas, obtaining very useful experimental data and results for the good practical understanding of the process and, therefore, for the technical training of the students.
The unit consists of a vertical capillary tube with a volatile solvent (liquid A) and gas (air), which will flow horizontally under laminar flow conditions in the upper end of the tube. This air is introduced by a computer controlled blower. The capillary will be introduced in an adjustable temperature computer controlled thermostatic bath, which will work following the double boiler method. The solvent will be evaporated slowly due to the thermal energy of the bath. And due to the concentration gradient, the gaseous solvent will be dispersed upwards, from the surface of the liquid solvent towards the pure air. The air flow will transport the molecules of the solvent and the volume of the liquid solvent in the tube will be reduced. There is an optical system with fine focusing adjustment to measure this level difference and displacement sensor.
This Computer Controlled Unit is supplied with the EDIBON Computer Control System (SCADA), and includes: The unit itself + a Control Interface Box + a Data Acquisition Board + Computer Control, Data Acquisition and Data Management Software Packages, for controlling the process and all parameters involved in the process.
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