Chemical composition in seawater of marine sediments, influences the phase behavior of natural gas hydrate by disturbing the hydrogen bond network in the water-rich phase before hydrate formation. The result is an inhibition in the hydrate formation with equilibrium conditions that are shifted to higher pressure and lower temperature. In this contest, the salts present in water act as thermodynamic inhibitors due to the interaction with the dipoles of the water molecules. For these reasons, more subcooling to overcome the structural changes is necessary in the hydrates formation. In this regards, in this study related to Task 1.1 called “Survey on marine natural gas hydrate” of PRIN project, some marine sediments samples, collected in National Antarctic Museum in Trieste, were analyzed and properties as pH, conductivity, salinity and concentration of main elements of water present in the sediments are reported. The results, obtained by ICP-MS and IC analysis, show that the more abundant cation is sodium and which, in smaller quantities but however not negligible are present calcium, potassium and magnesium, while the more abundant anions is chloride and appreciable is also sulfate. These results will be successively used to determine the “Thermodynamic parameters and the effect on salinity of water and hydrates formation” in the Task 2.2. of PRIN project.
Chemical characterization of water present in the natural marine sediment samples containing gas hydrates.
Andrea RossiPrimo
;Stefano Ferraro;Laura Petetta;Marco Zannotti;Rita Giovannetti
Ultimo
2020-01-01
Abstract
Chemical composition in seawater of marine sediments, influences the phase behavior of natural gas hydrate by disturbing the hydrogen bond network in the water-rich phase before hydrate formation. The result is an inhibition in the hydrate formation with equilibrium conditions that are shifted to higher pressure and lower temperature. In this contest, the salts present in water act as thermodynamic inhibitors due to the interaction with the dipoles of the water molecules. For these reasons, more subcooling to overcome the structural changes is necessary in the hydrates formation. In this regards, in this study related to Task 1.1 called “Survey on marine natural gas hydrate” of PRIN project, some marine sediments samples, collected in National Antarctic Museum in Trieste, were analyzed and properties as pH, conductivity, salinity and concentration of main elements of water present in the sediments are reported. The results, obtained by ICP-MS and IC analysis, show that the more abundant cation is sodium and which, in smaller quantities but however not negligible are present calcium, potassium and magnesium, while the more abundant anions is chloride and appreciable is also sulfate. These results will be successively used to determine the “Thermodynamic parameters and the effect on salinity of water and hydrates formation” in the Task 2.2. of PRIN project.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.