Attainable superheatings and stretchings of methane–hydrogen solutions

•We investigated spontaneous boiling-up of superheated liquid methane–hydrogen solutions.•Methods of lifetime measurement at constant pressure and temperature have been used.•Methods of continuous pressure reduction at isothermal conditions have been used also.•The results of experiments have been compared with classical nucleation theory. Methods of lifetime measurement at constant pressure and temperature and continuous pressure reduction at isothermal conditions have been used to investigate the kinetics of spontaneous boiling-up of superheated liquid methane–hydrogen solutions containing 0.25 and 0.50 mol% of hydrogen. The temperature dependence of the nucleation rate J has been determined at pressures p = 1.0, 1.6, and 2.0 MPa. Data on the attainable stretching pressure corresponding to nucleation rates J = (0.2–1.5)•108m−3s−1 have been obtained in the temperature range from 166 to 174 K. The results of experiments have been compared with classical nucleation theory. It is shown that at homogeneous nucleation a systematic underheating of the solution with respect to their theoretical values is connected with the size-dependence of the surface tension of critical bubbles. [Display omitted]