Geoff Vining's ethanol-water distillation column. I have found that this project solidifies students' understanding and appreciation of industrial experimentation.
Students can control six aspects of the column's operation.
Click here for more details on the column and the project. This link gives an actual project description I have used with students. Click here to actually run the column. Log in as Team 1 and use anonymous as the password. Click here for the Fortran source code for the column.