Mercury solubility and its modeling in an artificial natural gas at high pressures

Abstract

Getting to know of mercury (Hg) behavior will contribute to proper handling and removal of Hg in natural gas processing facilities. Hg solubility was measured in an artificial natural gas, composed of 88.80 vol. % methane, 5.10 vol. % ethane, and 6.10 % vol. % carbon dioxide, by a flow-type apparatus up to 6.031 MPa at (268 to 303) K. The Hg mole fraction ranged from 4.991 × 10–9 to 8.125 × 10–7 in the vapor phase. The Hg solubilities decreased with increasing pressure, and the pressure dependencies were similar to that in pure methane. The experimental data were correlated with the Peng–Robinson equation of state (PR-EOS) developed in the previous studies, where the attractive parameter of Hg was evaluated from the saturated vapor pressure, and binary parameters among the other constituents of the artificial natural gas determined from the VLE data available in the literature. The calculation results were acceptable and agreed with the experimental data without any additional corrections. The maximum and the minimum the absolute relative deviation (ARD) and the average absolute relative deviation (AARD) were 9.72, 0.0542, and 3.20 %, respectively.