Methane hydrate equilibria in silica gels with broad pore-size distributions

Equilibrium pressures for the dissociation of methane hydrates confined in silica gel pores of nominal radii 7.5, 5.0 and 3.0 nm were measured over a wide temperature range, and were observed to be higher than those for bulk, methane hydrate. A model is presented that allows the pore radius involved in each equilibrium to be determined front these data, so that the model exactly, reproduces the experimental equilibrium pressure. Based on this model, pore volume distributions were reconstructed and found to be in good agreement with those obtained from nitrogen desorption isotherms, indicating that hydrate formed nearly, uniformly in the available pores.