Design and implementation of a level control at the bottom of the first column of a continuous binary distillation tower

Abstract

The laboratory of the university has a continuous distillation tower where students carry out laboratory practice, require that student manipulate valve at high temperatures generating risk at operation. A control system was carried out on the plant to maintain the level of 0.18 meters in the bottom of the first column. For its identification, the inspection of the tower was carried out to identify the components of each distillation column. These tests allowed obtaining data from the point of operation during the start-up of the tower. With this information collected, a model was defined through the mass and energy balance. Additionally, the tower was simulated under the Aspen Hysys software to obtain the steady state and, over this point the dynamic system was analyzed through the linearized model to design the controller and test robustness. The control strategy implemented, with LabVIEW software, was ON-OFF with hysteresis due to limitations in the instrumentation. As a result, it was found that the time stabilization of the tower decreased from three hours to one hour to concerning the manual level control and, a better regulation was observed in the temperatures of the top of first column 96°C and second column 72°C.