Accelerated Methane Hydrate Formation by Ethylene Diamine Tetraacetamide As an Efficient Promoter for Methane Storage without Foam Formation

Reduction in the induction period of hydrate formation and enhancement of the gas hydrate growth are vital parameters in the application of gas hydrates technique for methane storage. In this work, ethylene diamine tetraacetamide (EDTAM) was developed as a new promoting agent for methane storage. The effect of EDTAM on methane hydrate formation parameters was evaluated by high-pressure micro differential scanning calorimeter (HP-DSC) and high-pressure autoclave cell at 2 °C and 8.0 MPa as the static and dynamic conditions, respectively. The results demonstrated that the onset temperature of methane hydrate formation was increased from -14 °C in the pure water system to -3 °C by adding 0.5 wt % EDTAM. The average conversion of water to hydrate was multiplied by a factor of 20.0 (from 3.2 wt % in pure water to 64.0 wt % in EDTAM solution) due to the presence of 0.5 wt % of EDTAM. Moreover, the EDTAM reduced induction time of methane hydrate formation by a factor of 4 in comparison with pure water in both static (DSC experiments) and dynamic (autoclave experiments) conditions. Also, EDTAM increased considerably the amount of consumed mole of methane, especially during the first stage of hydrate growth. Unlike surfactants, the addition of EDTAM does not induce formation of large amount of foam in the hydrate formation/dissociation process. All obtained results confirmed that the EDTAM is an efficient and prospective promoter for methane hydrate formation.