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

Hydrogen bunkering from a fuel island onto fishing vessels

Decarbonizing the fishing and aquaculture sector is an important goal for Norway as well as for the global shipping trade. Hydrogen is potentially a good fit for the energy demand of fishing vessels. For the fleet to switch to hydrogen as primary fuel, solutions for ensuring sufficient energy onboard must be found. One such solution could be to bunker the hydrogen at sea, in locations closer to the areas of operation of a fishing fleet. In the present work, we have investigated the bunkering of 250 bar gaseous hydrogen onto fishing vessels that require 4000 kWh of energy onboard. The first part focuses on the bunkering of a single vessel and an analysis of the technical parameters that affect and constrain the hydrogen bunkering rate. The second part focuses on the bunkering of several fishing vessels from a hydrogen refuelling station located offshore.Hydrogen bunkering from a fuel island onto fishing vesselspublishedVersio

Low-pressure liquid CO2 terminal - a model study of the loading of a liquid CO2 tanker

Low-pressure liquid CO2 terminal - a model study of the loading of a liquid CO2 tankeracceptedVersio

CO2 Wetting on Pillar-Nanostructured Substrates

CO2 capture by dropwise CO2 condensation on cold solid surfaces is a promising technology. Understanding the role of the nanoscale surface and topographical features of CO2 droplet wetting characteristics is of importance for CO2 capture by this technology, but this remains unexplored as of yet. Here, using large-scale molecular dynamics (MD) simulations, the contact angle and wetting behaviors of CO2 droplets on pillar-structured Cu-like surfaces are investigated for the first time. Dynamic wetting simulations show that, by changing the strength of the solid–liquid attraction ${\varepsilon }_{{\rm{Cu}}-{{\rm{CO}}}_{{\rm{2}}}},$ a smooth Cu-like surface offers a transition from CO2-philic to CO2-phobic. By periodically pillared roughening of the Cu-like surfaces, however, a higher contact angle and a smaller spreading exponent of a liquid CO2 droplet are realized. Particularly, a critical crossover of CO2-philic to CO2-phobic can appear. The wetting of the pillared surfaces by a liquid CO2 droplet proceeds non-uniformly. A liquid CO2 droplet is capable of exhibiting a transition from the Cassie state to the Wenzel state with increasing ${\varepsilon }_{{\rm{Cu}}-{{\rm{CO}}}_{{\rm{2}}}},$ increasing inter-pillar distance, and increasing pillar width. The wetting morphologies of the metastable Wenzel state of a CO2 droplet are very different from each other. The findings will inform the ongoing design of CO2-phobic solid surfaces for practical dropwise condensation-based CO2 capture applications.acceptedVersionLocked until 27.3.2021 due to copyright restrictions. This is an author-created, un-copyedited version of an article accepted for publication/published in [Nanotechnology]. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://dx.doi.org/10.1088/1361-6528/ab7c4

Heat transfer characteristics of CO2 condensation on common heat exchanger materials, method development and experimental results

Understanding condensation of CO2 is essential for e.g designing compact heat exchangers or processes involved in Carbon Capture and Storage. However, a consistent experimental campaign for condensation of CO2 on common materials is lacking. In this work, we present an experimental method and an associated laboratory setup for measuring the heat transfer properties of CO2 condensation on materials commonly used in heat exchangers for the liquefaction of CO2. We have investigated the heat transfer during CO2 condensation on copper, aluminum, stainless steel (316) to reveal the heat transfer dependency on surface properties. The experiments are conducted at three saturation pressures, 10, 15, and 20 bar and at substrate subcooling between 0 and 5K. The results show that the heat transfer coefficients decrease with increasing surface subcooling. It was also found that increasing the saturation pressure increases the heat transfer coefficient. The results indicate that surface roughness and surface energy affect the condensation heat transfer coefficient, and an increased roughness results in reduced heat transfer coefficients. The highest heat transfer coefficient is found for condensation on copper, for which the lowest surface roughness has been measured.publishedVersio

Medium scale distribution chains for hydrogen

A medium-scale hydrogen distribution chain, 3 tpd, is investigated for distribution in compressed gaseous form or in liquid form. The evaluation is complex and depends on factors like the upstream production and conditioning, the value chain energy efficiency, costs, chain flexibility, end user needs, and safety-related aspects. The article relates primarily to energy related aspects of a medium scale distribution chain for compressed hydrogen intended for heavy vehicle transport applications. Hydrogen production is assumed based on production by electrolysis from renewable sources. Some initial considerations related to the possible integration of liquid hydrogen in parts of the chain are also made. A compressed hydrogen value chain involves compression and re-compression in several stages, as well as a possible need for pre-cooling of the hydrogen prior to fuel tank charging. The results show a power demand for compression in the range 4.6-6.2 kWh/kgH2 depending on the efficiency of the compression. An additional power demand for refrigeration in the range of 0-0.25 kWh/kgH2 will be required depending on end pressure and fueling time limitations. In conclusion, the power demand in the distribution chain may be approximately 10-13 % of the power demand for electrolysis, assumed to be 50 kWh/kgH2. Liquefied distribution might be an alternative. The power demand needed for liquefaction and cryo-pumping may be estimated to about 10 kWh/kgH2 based on literature data. Thus, the power demand may be doubled compared to compressed gaseous value chain, but not more than 20 % of the power needed for production. Cost elements such as for storage tanks and compressors, required energy storage capacity, flexibility of end-use storage, as well as operational costs and safety-related issues may thus be more important factors in design and operation of medium scale distribution chains for hydrogen if compressed is to be compared to liquified distribution.acceptedVersio

Medium scale distribution chains for hydrogen

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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.acceptedVersio

A new facility for viscosity and density measurements for CO2 – rich mixtures relevant for CO2 transport and storage

For safe and cost-effective design, optimization, and operation of CO2 capture, transport, and storage (CCS) processes, accurate viscosity and density data of CO2-rich mixtures are required. Currently, there are large knowledge gaps in these properties, and it needs to be addressed for building good reservoir models and simulation tools. A modified two-capillary viscometer with several novel solutions for accurate measurement of viscosity and density of CO2-rich mixtures relevant for CO2 transport and storage has been designed and constructed. The new setup covers a range between 213.15 K and 423.15 K in temperature and up to 100 MPa in pressure. This paper describes the facility, calibrations, uncertainties estimation, and first test measurements performed using the setuppublishedVersio

Et energisikkert samfunn rustet mot angrep

publishedVersio