EXPERIMENTAL MEASUREMENT OF THERMODYAMIC, TRANSPORT PROPERTIES & INTERFACIAL PROPERTIES AS WELL AS PHASE BOUNDARIES RELEVANT TO THE CO2 CAPTURE, UTILIZATION & SEQUESTATION

Abstract

Large parts of the industry depend on combustion technologies, not only to satisfy the energy demand but also for production the processes. As a direct consequence Carbon Dioxide (CO2) has increased its concentration in the atmosphere, interfering with the natural Carbon Cycle. CO2 is the main contributor to the global warming among the Greenhouse-Effect Gases (water vapor, methane, nitrous oxide among the others). It is accepted by the scientific community (Intergovernmental panel on climate change, 2013) that the increasing concentration of CO2 in the atmosphere is mainly caused by human activities (anthropogenic) on a direct way e.g., cement production, fossil or high carbon content fuel combustion like power plants or indirect e.g., deforestation. There are international efforts to decrease CO2 atmospheric concentration, being the most promising alternative Carbon Capture Utilization & Sequestration (CCUS) technologies. CCUS consist in 4 stages: Capture, Purification, Transport, and Sequestration or Utilization. Two of these stages are crucial for CCUS, transportation and sequestration, where thermodynamic and transport properties are needed in order to achieve them. For the transportation stage, the study of phase behavior of CO2 rich mixtures containing H2O and other contaminants becomes necessary. This knowledge regarding CO2 rich mixtures is also useful for sequestration. There are other properties worth studying for sequestration and transportation such as mutual diffusivities, and interfacial tension (IFT). Given the lack of data regarding these properties available on the literature, simple methods to measure them were used and compared with available literature. Diffusion coefficient relevant to Sequestration conditions were estimated by three methods, the Stoke-Einstein diffusion coefficient formula is used to estimate pure diffusivities, statistical methods is proposed and the Fick’s second law for longer times at reservoir conditions. The las two models vary between 1.98 x10-8 and 8.52x10-8 m2/s, at 40-60°C and 5-20MPa. The effect of natural convection is observed in view of the effective diffusion coefficient at these conditions and supported by the Ryleigh number. IFT was measured with a pendant drop method at transport conditions of 5-40°C and 5- 20 MPa resulting in values between 9 and 43 𝑚𝑁/𝑚. Phase behavior of three systems containing CO2+Contaminants that represents oxidize, reduce and a real complex mixture were measured to see the influence of different pollutants on the dew and boiling lines. The change in these systems is related to the presence of compounds with critical points at very low temperatures and pressures. This work allows to increase the amount of available data relevant to CCUS technologies and extend the required data base.