Subsea natural gas dehydration with membrane processes: Simulation and process optimization

Abstract

Subsea processing enables broader exploration of oil and gas reservoir, giving an increased focus on developing alternative processes for subsea oil and gas treatment. This work provides a first evaluation of a new proposed subsea natural gas dehydration process with the use of a membrane contactor with triethylene glycol (TEG) for dehydration of the natural gas in combination with thermopervaporation for regeneration of the TEG. Simulation models are developed in Aspen HYSYS V8.6 and process optimization is performed on three different process designs with respect to staging of the regeneration. By introducing two thermopervaporation units in series the TEG flow rate is reduced by 55%, the membrane volume by 14.6% and the energy demands by 37.8%, compared to a design with one thermopervaporation unit. However, increasing the number of regeneration stages increases the complexity as additional heaters are introduced.