Technical and economic evaluations of the triethylene glycol regeneration processes in natural gas dehydration plants

A conventional natural gas dehydration plant and one based on striping gas concept, which employs triethylene glycol (TEG) as the dehydrating agent, were simulated using a steady state simulator (UniSim Design). The main units were included in the flowsheets, namely: absorber, flash units, heat exchangers, regenerator, and reboiler. All simulations were performed of about 25 L TEG/kg water absorbed. The equation of state (EOS) used in the simulation is the Peng Robinson (PR). The reboiler temperature of conventional regenerator and then the hot stripping gas flowrate, have been studied for their response to changes in the regenerated TEG concentration, dew point of sale gases, TEG losses (make-up), regenerator overhead vapor flowrate, and partial pressure of water vapor. Despite the increase in plant complexity, the fixed capital investment estimation proves an insignificant costs increase of the stripping gas configuration over the benchmark. It appears that stripping gas is a more effective way to improve the regenerated TEG concentration and entire dehydration plant performance.