Raw data of methane hydrate equilibrium / PXRD measurements in system CH4 – H2O – dimethyl sulfoxide and ice freezing points of DMSO aqueous solutions
Description
The raw data from the measurements of the methane hydrate equilibrium conditions in the methane-water-dimethyl sulfoxide system are given in the “Hydrate equilibrium (CH4-DMSO-H2O)” archive. A total of 54 equilibrium points have been measured. For each of them there is a separate .xlsx file in the archive with columns of numerical values of the following parameters measured by sensors of GHA350 autoclave: time, temperature (°C), gauge pressure (bar), stirrer speed (rpm). The file name represents the system under study and the point number. For example, the file name “5% DMSO_point 13” corresponds to the raw data obtained from measurements of the 13th equilibrium point (numbering from Table 1 of data paper [2]) for a 5 mass% aqueous solution of dimethyl sulfoxide. Cells D1:F3 of each file display numerical values of the masses and feed concentrations of the components in the aqueous phase. The raw data presented in the archive “PXRD analysis (CH4-DMSO-H2O)” are related to the powder X-ray diffraction study of the phase composition of gas hydrate samples synthesized from DMSO aqueous solutions. Diffractograms were recorded for 3 samples with a mass fraction of dimethyl sulfoxide in aqueous solution of 5, 55, and 20 mass%. For each sample, a separate file containing numerical values of 2θ (degree) and signal intensity (a.u.) is provided. The raw data from the determination of ice freezing temperatures of aqueous DMSO solutions at atmospheric pressure are given in the “Ice freezing (H2O-DMSO)” archive. The archive includes raw data from sixteen ice freezing point measurements. The file name indicates the mass fraction of DMSO and the point number (numbering from Table 6 of data paper [2]). Each file has a column with the measured temperature values of the sample at the specified time (one temperature reading every two seconds). The raw data is linked to the papers: [1] Anton P. Semenov, Rais I. Mendgaziev, Andrey S. Stoporev, Vladimir A. Istomin, Daria V. Sergeeva, Andrey G. Ogienko, Vladimir A.Vinokurov (2021) The pursuit of a more powerful thermodynamic hydrate inhibitor than methanol. Dimethyl sulfoxide as a case study // Chemical Engineering Journal, 423, 130227 DOI: 10.1016/j.cej.2021.130227 [2] Anton P. Semenov, Rais I. Mendgaziev, Andrey S. Stoporev (2023) Dataset for the experimental study of dimethyl sulfoxide as a thermodynamic inhibitor of methane hydrate formation // Data in Brief, 48, 109283 DOI: 10.1016/j.dib.2023.109283
Files
Steps to reproduce
I. Determination of methane hydrate equilibrium pressure and temperature from “Hydrate equilibrium (CH4-DMSO-H2O)” archive. To extract the equilibrium point (P, T) from a single experimental pressure temperature trajectory as follows: 1) Convert gauge pressure (bar) to absolute pressure (bar) by adding 1 to all gauge pressure values in the “Pressure (bar)” column. 2) Plot the experimental P T trajectory (the absolute pressure column is from step 1, and the temperature is from the “Temperature (ｰC) Bath” column). 3) Approximate the segments of the experimental P T trajectory before and after the endpoint of gas hydrate dissociation at a ramp heating (0.1 K/h) with linear functions. 4) The intersection of two linear functions is the endpoint of the methane hydrate dissociation with equilibrium pressure and temperature. 5) Convert the obtained values of the hydrate equilibrium temperature (°C) to (K), and the hydrate equilibrium pressure (bar) to (MPa). II. Determination of phase composition of samples from “PXRD analysis (CH4-DMSO-H2O)” archive. 1) Plot intensity as a function of 2θ (degree). 2) The peaks in the diffractogram correspond to the signals of the phases including sI methane hydrate and hexagonal ice Ih, which can be confirmed by comparison with literature and reference data. III. Determination of ice freezing temperatures of DMSO aqueous solutions from “Ice freezing (H2O-DMSO)” archive. 1) Plot the temperature (column “T, °C”) as a function of time. 2) The ice freezing point can be detected as the T value on the plateau after the temperature spike corresponding to the onset of ice crystallization in the supercooled aqueous solution.