Controle do processo TCPSD para a separação da mistura acetonitrila/benzeno/metanol.

Abstract

The separation via Triple-Column Pressure-Swing Distillation (TCPSD) can be used to separate different solvents from the fine chemical industry, and due to the large number of variables involved, along with thermal integrations and recycle streams, the definition of a control structure effectively becomes a complex problem. In this context, this work has as main objective the development and evaluation of plantwide control structures for the TCPSD process, used to separate the acetonitrile/benzene/methanol mixture. Using Aspen Plus© and Aspen Plus Dynamics© software, two control structures were evaluated, in which the product compositions are controlled by inference, through the temperature control of sensitive dishes. The main difference between the two structures is due to the fact that Control Structure 1 has a dual summation control loop of temperature of sensitive plates in the low-pressure column, manipulating the reflux ratio while Control Structure 2 has a control by inference by manipulating the heat load on the same column. When evaluating the results of the product compositions when reaching steady state and ISE values, it was concluded that both structures are able to control step-type disturbances in the flow and feed composition of the process. However, better results were observed in Control Structure 1. When comparing both control structures with structures using direct control obtained in the literature, it is observed that the latter has an advantage in terms of response time, but both stabilize in satisfactory results.