Experimental study of methane replacement in gas hydrate by carbon dioxide.

The process of replacement of methane molecules in clathrate hydrate by carbon dioxide is studied experimentally. The dependence of the replacement extent on the concentration of the gas mixture coexisting with the hydrate is determined. The kinetics of the replacement is governed by two relaxation modes with a characteristic time ratio of about 10.

[Results of duodenal non-formed lateral fistulas treatment].

Results of treatment of 66 patients with non-formed lateral fistulas of the duodenum by the methods of active external and double (external and internal) drainage of the fistula zone, and more rarely--by passive drainage or obturation were analyzed. Lethality of the patients was 35.4%.

Thermodynamic properties of methane hydrate in quartz powder.

Using the experimental method of precision adiabatic calorimetry, the thermodynamic (equilibrium) properties of methane hydrate in quartz sand with a grain size of 90-100 microm have been studied in the temperature range of 260-290 K and at pressures up to 10 MPa. The equilibrium curves for the water-methane hydrate-gas and ice-methane hydrate-gas transitions, hydration number, latent heat of hydrate decomposition along the equilibrium three-phase curves, and the specific heat capacity of the hydrate have been obtained. It has been experimentally shown that the equilibrium three-phase curves of the methane hydrate in porous media are shifted to the lower temperature and high pressure with respect to the equilibrium curves of the bulk hydrate.