Journal of Chemical and Engineering Data, Vol.60, No.2, 403-408, 2015
Phase Equilibrium Data and Model Comparisons for H2S Hydrates
Hydrogen sulfide is an exceptionally stable structure I (sI) gas hydrate forming guest molecule that is becoming increasingly prevalent in oil and gas production. However, phase equilibria data on pure hydrogen sulfide hydrate reported in the literature are relatively limited and inconsistent compared to other common hydrate formers such as methane or carbon dioxide. In this study, 61 hydrate phase equilibria measurements for sI hydrates containing hydrogen sulfide are reported in the temperature range from T = 273.68 K to 301.53 K and pressure range from p = 0.108 MPa to 1.960 MPa. Experimental data were measured using the isochoric pressure search (IPS) method which has been well established, as well as a modified IPS method, termed the phase boundary dissociation (PBD) method, which gives more efficient measurements of pure hydrate phase equilibria data. For example, it was shown in this work that using the new PBD method reduced the experimental run time to approximately 4.8 h per data point, compared to 40 h to 45 h per data point using the IPS method. The measured data for hydrogen sulfide hydrates were compared with predictions and experimental data reported in the literature, showing agreement between measurements and predictions within an average of 0.08 K for HydraFLASH 2.2 to 1.131 K for PVTSim 21 on average and literature within 0.21 K for Selleck et. al(10) to 1.42 K for Carroll and Mather(12) on average.