Triethylene glycol recovery by an energetically intensified thermosyphon-assisted falling film distillation unit: Experimental assessment on a pilot-scale unit and in-silico comparison with a conventional column from natural gas processing

Facing the emerging needs for energy-enhanced separation units, this work evaluated the triethylene glycol (TEG) regeneration, used as a dehydrating agent of natural gas from wells, by a novel thermosyphon-assisted falling film distillation technology, called Destubcal. The pilot-scale device has an innovative heat supply through a two-phase closed thermosyphon, which ensures a uniform energy distribution along the entire distillation tube. Based on current operating data from industrial water-rich TEG streams, different operating conditions were performed in the pilot-scale unit. The best recovery ratio (99.0%) was obtained with an evaporator temperature of 180 °C and a feed flow rate of 15 L/h. However, in order to maximize the bottom TEG composition, the best experimental condition achieved was 17 L/h and bottom temperature of 152.07 °C, due to an evaporator temperature of 170 °C. As a result, the Destubcal unit saved around 38.4% in energy requirement and reduced 49% the column height when compared to a conventional distillation column for the same recovery degree. Therefore, the proposed Destubcal technology can be considered a feasible alternative as recovery column for TEG regeneration in natural gas beneficiation units, with advantages of reduced dimensions and energy-saving operation.