Abstract
The temperatures and pressures of the three-phase equilibrium V-L(w)-H (gas - aqueous solution - gas hydrate) were measured in the CO(2) - H(2)O - dimethyl sulfoxide (DMSO) system at concentrations of organic solute in the aqueous phase up to 50 mass%. Measurements of CO(2) hydrate equilibrium conditions were carried out using a constant volume autoclave by continuous heating at a rate of 0.1 K/h with simultaneous stirring of fluids by a four-blade agitator at 600 rpm. The equilibrium temperature and pressure of CO(2) hydrate were determined for the endpoint of the hydrate dissociation in each experiment. The CO(2) gas fugacity was calculated by the equation of state for carbon dioxide for the measured points. The flow regime in the autoclave during the operation of the stirring system was characterized by calculating the Reynolds number using literature data on the viscosity and density of water and DMSO aqueous solutions. We employed regression analysis to approximate the dependences of equilibrium pressure (CO(2) gas fugacity) on temperature by two- and three-parameter equations. For each measured point, the value of CO(2) hydrate equilibrium temperature suppression ΔT(h) was computed. The dependences of this quantity on CO(2) gas fugacity are considered for all DMSO concentrations. The coefficients of empirical correlation describing ΔT(h) as a function of the DMSO mass fraction in solution and the equilibrium gas pressure are determined. This article is a co-submission with a paper [1].