Modeling and Simulation of Dehydration Technologies to treat a wet CO2 stream at a natural gas liquefaction facility in Peru

Resumen

This study evaluates the technical feasibility of three dehydration technologies applied to a saturated CO2 stream from the natural gas sweetening process at a natural gas liquefaction facility in Peru: chemical absorption with triethylene glycol (TEG), physical adsorption using molecular sieves (zeolite 3A), and permeation through polymeric membranes (SPEEK). Through process simulation, the performance of each technology was analyzed to meet moisture specifications for pipeline transport, Enhanced Oil Recovery (EOR), and aquifer storage. Results indicate that molecular sieves offer superior performance for deep dehydration, achieving residual contents below 0.5 ppmv with a CO2 recovery of 99.95%, and so was the only viable option for strict water content standards (<50 ppmv). TEG absorption presented a practical operating limit of 60 ppmv, being an efficient alternative for moderate water content specifications (<500 ppmv), although limited by flash gas emissions. Meanwhile, SPEEK membranes showed a dehydration performance limitation at 32 ppmv, exhibiting exponential energy consumption associated with sweep gas recirculation to achieve a CO2 recovery of 98.87%. It is concluded that technology selection critically depends on the CO2 end-use. The need for pre-treatment for hydrocarbon removal is also identified.