Gas chromatographic subsystem for fast on-line concentration profile measurements for advanced distillation column control

An automated gas chromatographic subsystem for the provision of fast and reliable concentration profile data for distillation column control is presented. The subsystem consists of a gas chromatograph, equipment for sample conditioning and a PC/AT compatible computer communicating with the supervisory process computer. A fast separation time is obtained through the use of a liquid chromatographic packing material and a high pressure drop across the column. Preliminary results show separation times below 10 s for the water-methanol-isopropanol system. Peak areas are quantified by use of parameter estimation in the frequency domain, a method that does not demand complete peak separation.