Corrosion mechanism and oxide scale evolution of austenitic stainless steels in supercritical CO2

NovoMem®, a collagen membrane derived from supercritical carbon dioxide (scCO2) decellularised porcine pericardium, is currently used as a barrier in dental bone grafts. In line with sustainable development goals, repurposing NovoMem® for vascular grafts presents a strategic opportunity. This study aims to evaluate NovoMem®'s decellularisation efficiency and extracellular matrix (ECM) preservation to assess its potential for vascular tissue engineering. The decellularisation efficiency was assessed using haematoxylin and eosin (H&E) staining and DNA quantification to confirm cellular removal and fulfilment of the proposed minimal criteria of decellularisation. ECM integrity was evaluated through collagen staining (Picrosirius red), elastin staining (Elastin van Gieson), and an insoluble collagen assay to measure total collagen. NovoMem® showed significantly reduced cellular content while preserving ECM architecture. The decellularised tissue had minimal residual DNA and retained its collagen framework. Compared with CorMatrix®, a commercially available chemically decellularised cardiac patch from porcine small intestinal submucosa (SIS) that has been repurposed for vascular grafts, NovoMem® exhibited superior decellularisation efficiency with comparable ECM preservation. NovoMem® also possesses biocompatibility, supporting mesenchymal stem cell growth. In conclusion, NovoMem® has minimal cellular content with preserved structural integrity, thus suggesting it as an effective vascular graft that could integrate with host tissues with minimal risk of alloreactivity, potentially improving graft efficacy and long-term patency.

Stabilizing Supercritical CO2 Cycles Using a Propane-Based Thermal Adapter for High-Temperature Nuclear Application

Numerical simulation study on the coupled heat transfer characteristics of liquid sodium and supercritical carbon dioxide

Supercritical CO₂ drying in nanoscale confinement: Molecular mechanisms and displacement efficiency

In-situ electrochemical insights into the corrosion mechanisms of electroless coatings under supercritical CO2: Extending a conventional coating to a new application domain

The growing relevance of aerogels in biomedicine demands the choice of compatible sterilization techniques with these materials. Conventional methods, such as ethylene oxide (EO) and gamma radiation (γ-rays) sterilization, have significant drawbacks while facing important environmental restrictions. In this study, supercritical CO2 (scCO2) sterilization is tested for polysaccharide (starch and alginate) aerogels as an eco-friendly alternative to conventional procedures. Three post-processing treatments under different CO2 exposure regimes (static, dynamic and combined) and in the presence of H2O2 as additive were developed and assessed to reach sterility assurance levels (SAL) below 10-6. After sterilization, a vacuum treatment was implemented to ensure a low residual presence of H2O2 in the aerogels so that the material biocompatibility was not compromised according to in vitro cell tests with fibroblasts. The residual adsorbed H2O2 was quantified for the first time in aerogels by nuclear magnetic resonance spectroscopy. The effects of the supercritical sterilization treatments on the textural and chemical properties of the aerogels were evaluated and compared to those treated with EO and γ-rays. Results highlight the unique efficiency of scCO2 sterilization as a post-processing method that preserves the aerogel structure while offering an eco-sustainable potential for producing sterile and biocompatible materials.

Supercritical CO₂ Brayton cycles coupled with advanced Molten Salt Reactors offer a promising zero-GHG propulsion alternative for large ocean-going vessels. Their high power density, favourable part-load performance, and compatibility with compact heat-exchanger technologies make them strong candidates for deep-sea decarbonisation. The main objective of this study is to identify optimal sCO₂ cycle and powertrain configurations for marine nuclear propulsion through integrated thermoeconomic optimisation, using a very large ore carrier as a representative application case whose scale and operational regularity render it particularly suitable for nuclear propulsion. A comprehensive thermoeconomic modelling framework is formulated, encompassing multiple sCO₂ cycle variants and three shafting configurations (electric, mechanical, hybrid). Detailed design and off-design component models are combined with energy, exergy, and cost correlations within a generic super-configuration, enabling unified synthesis, design, and operational thermoeconomic optimisation. The optimal solution achieves a design-point efficiency of approximately 45%, comparable to modern large two-stroke diesel propulsion systems, while eliminating direct GHG emissions. Optimisation results reveal two dominant configurations depending on the objective: a fully electric recompression cycle for maximum efficiency, and a hybrid mechanical–electric arrangement for minimum annualised cost. Reactor-cost sensitivity shows that recompression cycles remain optimal across a wide cost range, confirming their structural robustness. Part-load optimisation demonstrates high efficiencies down to 50% load and yields optimal operating set-points for future control development. A preliminary operational lifetime comparison with a conventional diesel-based ship indicates that, despite much higher capital expenditure, the nuclear sCO₂ system achieves a lower annualised cost and becomes economically favourable after approximately ten years of operation. Overall, the results highlight the technical and economic viability of nuclear sCO₂ propulsion for large commercial vessels and provide a rigorous framework for future component design, integration, and assessment. • A thermoeconomic optimisation framework is developed for MSR-driven sCO₂ cycle applied to a marine propulsion system. • A generic super-configuration enables unified optimisation of cycle synthesis, component design, and shafting arrangements. • Optimal solutions achieve about 45% efficiency and identify electric and hybrid powertrains as the best-performing configurations. • Sensitivity and lifecycle analyses show the recompression cycle's robustness and the economic competitiveness of nuclear sCO₂ propulsion. • The nuclear sCO₂ system achieves a lower annualised cost and becomes economically favourable after approximately ten years of operation.

Cascading valorization of walnut shells via supercritical CO2: Phenolic bio-oil extraction and syngas/char co-production

• Provide innovative experimental data of filling/emptying CO 2 tanks. • Comprehensive analysis of the dynamic behaviour of the CO 2 tanks. • Better understanding of CCES operating process with liquid storages. Energy storage systems are becoming a highly topical issue with the increasing integration of solar and wind energy into the electricity mix. Thermomechanical energy storage systems are attracting growing interest. They are based on thermodynamic cycles to store electricity under mechanical and/or heat energy. Compressed CO 2 energy storage systems are one emerging example. Despite numerous modelling studies, experimental investigations remain very limited. Existing experiments are restricted to gaseous CO 2 at low pressures. However, these systems are mostly investigated with storage tanks containing liquid or supercritical CO 2 . This study addresses this gap by presenting the first experimental results on the dynamic behaviour of reservoirs containing CO 2 in multiphase conditions (coexistence of liquid – gaseous CO 2 ) and reaching supercritical pressures. For that purpose, an experimental test rig based on conventional and commercial components was developed. It is composed of a 320 L low-pressure storage, a 240 L high-pressure storage and a 3 kW CO 2 pump. The mass flow rate ranges from 100 to 320 kg.h −1 , corresponding to charging times from 1 to 1.8 h (including a balancing step) with a maximal pressure of 22 MPa. The results indicate an inability to maintain a constant pressure during a tank emptying or filling due to temperature changes. During a discharge, the pressure in the high-pressure storage drops from 22 to around 3 MPa. As a consequence, this study highlights the possibility to balance the pressure after a discharge.

• sCO 2 reverse Brayton high-temperature heat pumps are studied for industries. • Heat production temperatures up to 250 °C are examined. • Low-grade waste heat sources in the range of 50–120 °C drive the heat pump. • Internal heat exchanger increases COP by up to 8.13% and exergy efficiency by 6.54%. • Reheating and internal heat exchanger cycles improve COP by up to 15.5%. High-temperature heat pumps (HTHPs) are high-potential technologies for the decarbonization of low- and medium-temperature industrial heating processes. The conventional HTHPs can deliver heat up to 150-160 °C, while the process heat production at higher temperatures is a challenge that has attracted a lot of research in the last year. The goal of this work is to conduct a detailed investigation of different configurations of supercritical CO 2 reverse Brayton HTHPs, aiming to determine the most efficient and promising designs. This analysis investigates different process heat production from 150 °C up to 250 °C, while the HTHPs are driven by low-grade waste heat in the range of 50 –120 °C. This work is performed with developed mathematical thermodynamic models in Engineering Equation Solver, which are verified with literature data. According to the results of this analysis, the recompression is a proper solution for low heating production temperatures (mainly at 150 °C), while at higher heating production temperatures, the Reheating with an internal heat exchanger has to be selected. The application of the internal heat exchanger enhances the coefficient of performance up to 8.13% and the exergy efficiency up to 6.54%. For the typical case with source temperature at 100 °C, the average COP enhancement is found at 3.9% with internal heat exchanger, at 12.5% with Reheating with internal heat exchanger and at 15.5% with Double reheating with internal heat exchanger compared to the Simple cycle.

Scaling considerations for supercritical carbon dioxide cycles including turbomachinery loss models

Methane production via anaerobic digestion in coal reservoirs with the participation of supercritical carbon dioxide

Dye adsorption in regenerated hydrolyzed cotton linter cellulose beads from N-methylmorpholine N-oxide: High vs. low surface charge and freeze-drying vs. supercritical carbon dioxide drying

Machine learning-based corrosion prediction in supercritical carbon dioxide transport pipelines: Model evaluation and experimental validation

Transient and mechanical analysis of phenomena of supercritical carbon dioxide jet into lead-bismuth eutectic in lead-cooled fast reactor

This study advances continuous supercritical carbon dioxide (scCO₂) drying of aerogel particles by introducing a non-invasive optical method to determine particle residence time in a countercurrent extraction column. In countercurrent operation, scCO₂ flows upward while the particle suspension in ethanol enters from the top. The method enables precise, real-time residence time measurement under high pressure conditions without disturbing the process. The effects of pressure (100–150 bar), temperature (40–80 °C), CO₂ flow rate (30–80 g/min), and suspension flow rate (10–45 g/min) on residence time and drying efficiency were accordingly analyzed. Experiments were performed in a 1.25 m high extraction column, with an internal diameter of 20.5 mm, using highly spherical alginate beads with a diameter of ~ 400 µm as a model system. Evidence of effective solvent removal throughout the whole operation range was provided by determination of the residual ethanol content in the intact aerogel beads after the drying process (0.0053–0.0341 g ethanol /g aerogel ). The dried products featured a specific surface area of 363 ± 27 m²/g, a mesopore volume of 3.2 ± 0.7 cm³/g, consistent with the typical range of alginate aerogels. The combined insights provide a comprehensive picture of the countercurrent column’s operational response and allow the definition of practical operating windows. Elevated temperature and high pressure provide the most favorable trade-off between short residence time and minimized residual ethanol, maximizing the time-specific yield. Overall, the approach establishes a robust, transferable framework for optimizing continuous scCO₂ drying of aerogel particles and supports extension to other particle sizes and formulations. • Continuous scCO₂ drying of freely settling aerogel beads in a countercurrent column • Non-invasive optical residence time distribution measurement in situ under high-pressure operation • Statistical model links P, T, CO₂ and suspension flow to residence time and drying efficiency • ~400 µm alginate beads dried to residual ethanol level of 0.0053–0.0341 g/g • Aerogel quality preserved: 363 m²/g surface area and 3.2 cm³/g pore volume

Simulation study of flow field characteristics of supercritical carbon dioxide jets into lead-bismuth eutectic pool

Analysis of the blowdown of supercritical carbon dioxide from simple vessel

Tangerine leaves were valorized as a source of natural antioxidants for protecting soybean oil against lipid oxidation. Initial Soxhlet extracts obtained using hexane (Hex S), ethyl acetate (EtOAc-S), and ethanol (EtOH-S) showed that the Hex-S extract provided the highest oxidative stability, highlighting the relevance of nonpolar compounds in delaying lipid oxidation. To develop a more sustainable alternative to hexane extraction, supercritical CO 2 (SC-CO 2 ) extraction was optimized using a central composite design, assessing the effects of pressure (100, 200, and 300 bar) and temperature (40, 50, and 60 °C) on the extract's antioxidant performance. The optimal SC-CO 2 extract, obtained at 273 bar and 37 °C, extended the induction period of soybean oil oxidation to 5.2 h, outperforming both the Hex-S extract (4.4 h) and the control sample (3.8 h), and resulted in a lower p-anisidine value (13.36). These activities may be attributed to extracted bioactive compounds, such as linalool, thymol, and tangeretin. • Tangerine leaves arrayana variety were valorized as a natural antioxidant source. • Optimal SC-CO₂ extraction conditions (37 °C, 273 bar) enhanced the extract composition. • Monoterpenes, sesquiterpenes, and flavonoids were selectively recovered. • The extracts improved soybean oil oxidative stability (induction time increased). • Extraction time decreased from 10 h to 40 min with minimal solvent residue.