On estimating the water content of gas in equilibrium with gas hydrate or ice

Experimental data for water content of gases and petroleum fluids in equilibrium with gas hydrates/ice are rare and scarce. This is partly due to the fact that water content is very low at these conditions, and, hence, generally very difficult to measure. Furthermore, reaching hydrate/ice equilibrium is a very time-consuming process. Fortunately, estimation of corresponding water content in equilibrium with meta-stable liquid water is easier. Expressions have been developed, based on equality of fugacity in equilibrium phases for relating water content in equilibrium with gas hydrates/ice, to corresponding water content in equilibrium with metastable liquid water. The results of this method are then compared with some experimental data reported in the literature. These results show that using only data on corresponding water content in equilibrium with metastable liquid water can lead to relatively acceptable predictions Of water content in equilibrium with gas hydrates/ice. (c) 2007 American Institute of Chemical Engineers