Details

Autor(en) / Beteiligte

• Mu, Liang
• Tan, Qiqi
• Li, Xianlong
• Zhang, Qingyun
• Cui, Qingyan

Titel

Measurements and Modeling of the Hydrate Phase Equilibrium Condition of Sour Gas Mixtures in the Presence of Salts and Alcohols

Ist Teil von

• Journal of chemical and engineering data, 2022-09, Vol.67 (9), p.2563-2572

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2022

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Sour natural gas can easily form clathrate hydrate and cause the pipeline blockage in transmission; salts and alcohols are usually added for shifting its phase boundary to inhibited regions. In this study, the hydrate equilibrium conditions of two (CH4 + CO2 + H2S + N2) quaternary gas mixtures (M1 and M2) in the NaCl solutions with and without methanol (MeOH) are measured using the isochoric pressure searching method. The results indicated that the hydrate phase boundary of sour gas mixtures mainly depended on its composition, where the content of H2S played a more important role than that of CO2. The presence of NaCl evidently decreased the hydrate equilibrium temperature of gas mixtures, while the temperature suppression effect did not present a linear relation to its concentration. Then, the 20 and 30 wt % MeOH was added to 5 wt % NaCl solution, for the CO2-rich (M1) and H2S-rich (M2) gas mixtures; the hydrate suppression temperatures reached 12.6 and 17.6 K, respectively. The measured data sets passed the thermodynamic consistency and have good reliability. A thermodynamic framework based on Chen-Guo model and UNIQUAC equation was proposed to predict the hydrate equilibrium condition of sour gas and mixtures in the aqueous solutions containing salts and alcohols. For the data sets measured in this work, our proposed model presented a smaller AADP (%) (average absolute deviation percent in pressure) than the commercial programs (PVTsim, Multiflash, CSMGem). For the literature data sets (116 points) on the sour gas and mixtures in the presence of alcohols [MeOH and ethylene glycol (EG)] and/or salts (NaCl, KCl, and CaCl2), this study also exhibited a higher accuracy than previous works.