Vapor-liquid equilibrium data for the carbon dioxide and oxygen (CO2 + O2) system at the temperatures 218, 233, 253, 273, 288 and 298 K and pressures up to 14 MPa

Accurate thermophysical data for the CO2-rich mixtures relevant for carbon capture, transport and storage (CCS) are essential for the development of the accurate equations of state (EOS) and models needed for the design and operation of the processes within CCS. Vapor-liquid equilibrium measurements for the binary system CO2+O2 are reported at 218, 233, 253, 273, 288 and 298 K, with estimated standard uncertainties of maximum 8 mK in temperature, maximum 3 kPa in pressure, and maximum 0.0031 in the mole fractions of the phases in the mixture critical regions, and 0.0005 in the mole fractions outside the critical regions. These measurements are compared with existing data. Although some data exists, there are little trustworthy literature data around critical conditions, and the measurements in the present work indicate a need to revise the parameters of existing models. The data in the present work has significantly less scatter than most of the literature data, and range from the vapor pressure of pure CO2 to close to the mixture critical point pressure at all six temperatures. With the measurements in the present work, the data situation for the CO2+O2 system is significantly improved, forming the basis to develop better equations of state for the system. A scaling law model is fitted to the critical region data of each isotherm, and high accuracy estimates for the critical composition and pressure are found. The Peng-Robinson EOS with the alpha correction by Mathias and Copeman, the mixing rules by Wong and Sandler, and the NRTL excess Gibbs energy model is fitted to the data in the present work, with a maximum absolute average deviation of 0.01 in mole fraction

Enabling CCS via Fiscal Metering

Carbon Capture and Storage (CCS) will have to turn into a massive industry in order to play a significant role in the mitigation of anthropogenic climate change. The EU Emissions Trading Scheme (ETS) directive establishes that emissions captured, transported, and stored are considered as ‘not emitted.’ Accurate measurements will enable businesses who have implemented CO2 capture to omit buying or selling their CO2 Emission Unit Allowances (EUAs) under the ETS, when transferring the CO2 to geological storages. In this context, fiscal metering technologies, calibrated and verified for CCS relevant streams, would allow rightful checks and balances in CO2 trade. The present work provides a benchmarking study, looking into the applicability of various metering technologies for CO2 flow measurements. The requirements to further verify the potential of such technologies in the context of industrial needs are also examined. These requirements are then incorporated into the basic design of an experimental facility with focus on operational flexibility, accurate and traceable composition and flow rate, and controlled operating conditions. The study encompasses a thorough evaluation of the metering market, including first-hand proprietary information, detailed engineering considerations for all subsystems of the experimental facility, and considerations for industrial needs based on undergoing CCS projects and plans. The study results show that although Coriolis and Ultrasonic meters seem like promising technologies for CCS, further verification at relevant conditions is required. This verification entitles a high level of innovation, particularly for accurate reference measurements for CO2 mass and volume flow meter calibration to comply with the current regulatory framework. The results presented constitute the first step towards the construction of the world’s first large-scale test facility for CCS fiscal metering technologies. The implications of such a facility are enabling fair business throughout the CCS value chain, hence levering CCS towards widespread deployment

Accurate Phase Equilibrium Measurements of CO2 Mixtures

AbstractA new setup for accurate measurement of phase behavior of CO2-rich mixtures relevant for CCS has been designed, covering a range between - 60 and 150°C in temperature and 0.4 and 20MPa in pressure. In order to design safe and efficient infrastructure for CCS, the exact properties of these mixtures are required, and currently there are large knowledge gaps that need to be closed regarding the phase behavior. This paper reports a description of the experimental setup, how uncertainties will be verified and contained, and the very first test measurements performed using the setup

A New Facility on Accurate Viscosity and Density Measurements

A new facility for accurate measurement of viscosity and density of CO2-rich mixtures relevant for CO2 Capture and Storage (CCS) has been constructed. The facility includes a two-capillary viscometer with several novel solutions to enable high performance over a range between 213.15 K and 473.15 K (-60 and 200 °C) in temperature and up to 100 MPa (1000 bar) in pressure. There are currently very little data available on viscosity of liquid CO2-rich mixtures relevant for CCS, needed for instance in simulations of injection processes and reservoirs. Integrated in the setup is also a densimeter which is controlled to the same temperatures and pressures. Apart from providing density data, this enables accurate conversion between kinematic and dynamic viscosity. The total uncertainty target of the facility is 0.1 % (95% confidence level), except close to the critical point

Co2-Enhanced Geothermal Systems for Climate Neutral Energy Supply

The main objective of the research carried out by the Polish-Norwegian scientific team is to analyze the potential for implementation and efficiency of enhanced geothermal systems (EGS) using CO2 as a working fluid (CO2-EGS). This technology has attracted much interest of the scientific community in the last two decades due to the additional benefit of CO2 geological storage that is occurring during the power generation process. The purpose of this technology is to mitigate climate change by producing clean geothermal energy and simultaneously reduce carbon dioxide emissions to the atmosphere coming from the combustion of fossil fuels. Within the paper, the scope of the EnerGizerS project is indicated. Moreover, the preliminary results of case study locations for the CO2-EGS in both Poland and Norway are presented

Vapor-liquid equilibrium data for the carbon dioxide and nitrogen (CO2+N2) system at the temperatures 223, 270, 298 and 303 K and pressures up to 18 MPa

A new setup for the measurement of vapor-liquid phase equilibria of CO2-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 CO2+N2 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 CO2+N2 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