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This work aimed the study and optimization the recovery method of isobutane and hexene in a distillation column. This column is part of the process to obtain high density polyethylene in a petrochemical industry. To carry out the simulation of the process, the software ASPEN PLUS, ASPEN DYNAMICS and the process data were used, which enabled a simulation with the expected conditions to analyze the causes of the presented problems and propose improvements in its operation. For study the behavior of the column in steady state, it was necessary to define the thermodynamic model by analyzing the composition of the feed currents and the operating pressure data. Based on the new operating point and the steam restriction of the referent, a new reboiler was designed with the purpose of increasing the area of thermal exchange, supplying the energy deficit of the process. Another option, aiming the cost minimization, was the design of an identical reboiler to the existing to operate in parallel with it. Finally, the existing control is evaluated, and it is proposed a background level control of the column through the bottom flow, control of the bottom temperature of the column manipulating the thermal load of the reboiler and control of lateral withdrawal, changing the set point from stage 24 to stage 31, resulting in a better response to the disturbance in the feed stream and ensuring a high hexene composition in lateral withdrawal |
