A new setup for the measurement of vapor-liquid phase equilibria of CO 2 -rich mixtures relevant for carbon capture and storage (CCS) transport conditions is presented. An isothermal analytical method with a variable volume cell is used. The apparatus is capable of highly accurate measurements in terms of pressure, temperature and composition, also in the critical region. Vapor-liquid equilibrium (VLE) measurements for the binary system CO 2 +N 2 are reported at 223, 270, 298 and 303 K, with estimated standard uncertainties of maximum 0.006 K in the temperature, maximum 0.003 MPa in the pressure, and maximum 0.0004 in the mole fractions of the phases. These measurements are verified against existing data. Although some data exists, there is little trustworthy data around critical conditions, and our data indicate a need to revise the parameters of existing models. A fit made against our data of the vapor-liquid equilibrium prediction of GERG-2008/EOS-CG for CO 2 +N 2 is presented. At 223 and 298 K, the critical region of the isotherm are fitted using a scaling law, and high accuracy estimates for the critical composition and pressure are found.

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The efficiency of using sequential quadratic programming (SQP) for the optimization of a PRICO process for the production of liquefied natural gas (LNG) is demonstrated. Most of the returned objective values have been better, and the execution times much lower, than in most previously published work on similar optimization cases. The optimization runs discussed in this paper require around 5 minutes of execution time.

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Contributions to the acoustic signal sensitivity of fiber distributed-feedback (DFB) lasers in air are investigated both theoretically and experimentally. The theoretical results show that the dominant contribution to the laser frequency shift comes from adiabatic temperature shifts in the surrounding air at lower frequencies and from pressure at higher frequencies. The transition frequency was found to be between 5 and 20 kHz, depending on the elastic boundary conditions of the fiber laser. The acoustically induced frequency shifts of two fiber DFB lasers were measured, and the sensitivities varied from 0.61 MHz/Pa at a 100-Hz acoustic frequency to 0.34 kHz/Pa at a 15-kHz acoustic frequency.