Technical paper
Influence of Process Operations on VOC and BTEX Emissions from Glycol Dehydration Units
Over the past several years, concerns about hydrocarbon emissions from the regenerator vent in glycol dehydrators has become a significant issue. This paper illustrates the prediction capabilities of PROSIM® for analyzing these concerns. First, the paper illustrates that predictions made by PROSIM compare favorably to data from the API Glycol Reboiler Emissions Work Group. Next, PROSIM shows that while a significant amount of non-aromatic VOC emissions are released in the flash separator, a small fraction of BTEX emissions are evolved at normal conditions. PROSIM indicates that over-circulation does not enhance dew point depression, but will cause a nearly linear increase in the amount of BTEX compounds emitted from the unit. Next, various contactor pressures are analyzed which show that higher emissions result from lower pressure units due to the increased amount of water that must be absorbed. Finally, a comparison between DEG and TEG facilities with similar circulation rates indicates that approximately 30-40% more BTEX emissions occur when using TEG than DEG.
Over the past several years, concerns about hydrocarbon emissions from the regenerator vent in glycol dehydrators has become a significant issue. This paper illustrates the prediction capabilities of PROSIM® for analyzing these concerns. First, the paper illustrates that predictions made by PROSIM compare favorably to data from the API Glycol Reboiler Emissions Work Group. Next, PROSIM shows that while a significant amount of non-aromatic VOC emissions are released in the flash separator, a small fraction of BTEX emissions are evolved at normal conditions. PROSIM indicates that over-circulation does not enhance dew point depression, but will cause a nearly linear increase in the amount of BTEX compounds emitted from the unit. Next, various contactor pressures are analyzed which show that higher emissions result from lower pressure units due to the increased amount of water that must be absorbed. Finally, a comparison between DEG and TEG facilities with similar circulation rates indicates that approximately 30-40% more BTEX emissions occur when using TEG than DEG.