Purification and production of bio-ethanol through the control of a pressure swing adsorption plant

Bioethanol can be used as fuel obtained from second-generation raw material (cane bagasse) in order not to affect food sovereignty. One of the processes that have achieved a greater production and recovery of bioethanol is pressure swing adsorption (PSA), which uses zeolites to separate and purify the ethanol-water mixture. The aim of this work focuses on implementing a discrete Fault Tolerant Control and discrete PID on a virtual PSA plant for ethanol production maintaining the purity stable under the effects of combined faults in the actuator (flow valve) that can affect the PSA plant. It was observed that both controllers have great performance implementing it in the Hammerstein–Wiener model, but when performing the tests with the PSA plant, the FTC presented greater robustness and performance (achieving a stable purity of 0.9892 molar fraction) to reduce the effects of combined faults considering changes of trajectories, on the other hand, the discrete PID presents difficulties to reduce the effect of the ramp-type fault since the purity drops to 0.82 in molar fraction. The discrete FTC achieves to produce bioethanol (above 99% wt) with purity values that international fuel standards allow.