Modulated DSC for gas hydrates analysis

Abstract

Modulated DSC has been applied to the study of methane, ethane and propane hydrates at different hydrate and ice concentrations. The reversing component of the TMDSC curves, makes it possible to characterize such hydrates. Methane and ethane hydrates show the melting-decomposition peak at a temperatures higher than the ice contained in the sample, while propane hydrate melts and decomposes at lower temperature than the ice present in the sample. The hydrate peaks tend to disappear if the hydrate is stored at atmospheric pressure. Guest size and cavity occupation fix the heat of dissociation and stability of the hydrates, as confirmed by parallel tests on tetrahydrofurane hydrates

Self-Preservation at Low Pressures of Methane Hydrates with Various Gas Contents

“…When the amount of added water is known, the percentage of hydrate in the sample can be calculated from the pressure drop. Modulated differential scanning calorimetry (MDSC) can be used for hydrate characterization. − …”

Instrumental analysis of gas hydrates properties

“…[9] Distinguishing hydrates from ice is another challenge for the implementation of most of the aforementioned techniques. [59] Apart from these, extensive data management, excellent computational models, and efficient communication between experimental engineers, scientists, and the molecular simulation engineers are also critical.…”

“…[54 -57] MicroDSC and thermal modulated differential scanning calorimetric (TMDSC) have also been used for hydrates analyses at a greater range of working temperatures and pressures, and for the detection of processes that occur simultaneously, such as melting, lattice destruction and decomposition. [58,59] Crystallographic analysis of gas hydrates Crystallographic methods are often used for the determination of the atomic and/or magnetic structure of materials. The analysis is dependent on the diffraction patterns emerging from a sample that is targeted by a beam of X-rays [X-ray diffraction (XRD)], neutrons (neutron diffraction), or electrons (electron diffraction).…”

In Situ Characterization of Mixed CH4–THF Hydrates Formed from Seawater: High-Pressure Calorimetric and Spectroscopic Analysis

“…A detailed description of the experimental setups, (i) high-pressure microdifferential scanning calorimeter (HP μ-DSC from Setaram Inc.) apparatus − and (ii) a dispersive laser Raman spectrometer (SRaman-532) coupled with a high-pressure reactor , (refer to Supporting Information Figure S1), along with the procedure employed is available in our previous publications …”