Selective dehydration of high-pressure natural gas using supersonic nozzles

Supersonic separators are proposed in this paper as a compact high-pressure processing system capable of selectively removing water from high-pressure natural gas streams without affecting the hydrocarbon content. A computer simulation linked to a thermodynamic property package is presented to predict the water removal efficiency and to compare the proposed system with conventional techniques. Some of the advantages of the proposed system include compactness, self-induced refrigeration, high gas velocity in the nozzle and low risk of hydrate deposition. Selective water removal with the proposed method can be achieved by controlling the design parameters: e.g., increasing the inlet pressure with constant temperature, increasing the inlet temperature with constant outlet pressure, and controlling the backpressure.