Optimal operation of an integrated energy system for a concentrated solar power plant based on a supercritical CO2 plume heat pump

Comprehensive 4E analysis of a biomass-fired CCHP system integrating a high-efficiency absorption chiller and a supercritical CO2 Brayton cycle

Experimental study on supercritical CO₂ flow and heat transfer in rectangular microchannel PCHE under recompression cycle conditions

Structural reconstruction characteristics of mesopores, macropores, and fractures in anthracite matrix induced by supercritical CO2 injection

Aroma profiles of ginger essential oils extracted by steam distillation and supercritical CO2 fluid extraction

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.

Supercritical CO₂ debinding: A promising method for binder removal in ceramic fabrication with potential applications in additive manufacturing – A review

Dual-functional oriented PVDF/CNTs/BaTiO3 composite foams fabricated by supercritical CO2 foaming for electromagnetic shielding and piezoelectric sensing

Effect of supercritical CO2 on the anisotropic and seepage characteristics of shale

The roots of Cannabis sativa L., historically overlooked, are gaining attention as a potential source of bioactive compounds with antioxidant, antimicrobial, and anti-inflammatory properties. While previous studies have focused on extractions using ethanol, water, or supercritical CO2, the feasibility of edible oil-based extraction remains largely unexplored. This study evaluated the extraction of root compounds using hemp seed oil, MCT coconut oil, and grape seed oil at six temperatures (50–90 °C). Extracts were analyzed by GC–MS for compound identification and quantification, and antioxidant activity was assessed using the DPPH assay, ABTS test and β-carotene bleaching method, with results statistically evaluated by ANOVA. Friedelin was successfully extracted with all oils, with grape seed oil yielding the highest concentration (0.810 mg/g dry roots), achieving recoveries higher than those previously reported for ethanol-based extractions. All extracts demonstrated positive antioxidant activity, with grape seed oil, both alone and combined with extracts, showing higher values across the three methods. ANOVA revealed a significant effect of solvent type on both Friedelin concentration and antioxidant capacity. These results demonstrate that edible oils are effective solvents for extracting bioactive compounds from C. sativa roots, supporting their potential application in cosmetic or medicinal formulations.

In the framework of integrated pest management, plant-based insecticides represent a promising tool for the control of insect pests. Indeed, N-alkylamides extracted from Acmella oleracea (L.) RK Jansen (Asteraceae) have been recently studied for their insecticidal properties. The encapsulation of these substances into stable formulations, like nanoemulsions (NEs), could boost their efficacy and stability. Herein, a N-alkylamide-enriched fraction (AEF) encapsulated into a stable NE was tested against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), a key tomato pest, able to develop resistance towards chemical insecticides. Acmella oleracea was reported to be effective against many target species, but this is the first time that this extract was tested against T. absoluta in terms of toxicity against eggs, ingestion toxicity on larvae and repellence on adults. The AEF, containing 42.8% of spilanthol, was prepared by combining two eco-friendly techniques, namely supercritical CO2 extraction and wiped-film short path molecular distillation, and then encapsulated into a stable NE. Preliminary tests on the phytotoxicity of the AEF-NEs at 0.25 and 0.5% (w/w) a.i., compared with a control NE solution (i.e., the AEF-free NE) and a negative control (distilled water), showed a negative effect on tomato plants at the highest concentration. On this basis, three concentrations (0.06, 0.125, and 0.25% a.i.) were evaluated against eggs (topical toxicity), larvae of 2nd instar (ingestion and topical toxicity), and adults (ovideterrence) of T. absoluta. The results showed that all adopted AEF-NE concentrations caused a significant inhibition in egg hatching (>20%). The larval survival, at the end of the evaluation (72 h), in ingestion toxicity tests were significantly different in the AEF-NEs at 0.06, 0.12, and 0.25% (56.7, 33.3 and 26.7%, respectively) compared with control NE and distilled water (100% both). Similar results were obtained in the adult emergence in ingestion toxicity comparing AEF-NEs at 0.06, 0.12, and 0.25% (64.7, 50.0 and 75.0%, respectively) with control NE and distilled water (100% both). Finally, a significant ovideterrent effect was shown by the concentrations 0.125 and 0.25% of the AEF-NEs (% of egg laid: 7.5 and 27.4% respectively), compared with distilled water. Overall, the AEF-NE tested showed promising and encouraging effectiveness as ovicidal and larvicidal against T. absoluta. This supports its potential use as an effective alternative to synthetic products for the control of this important pest.

We report herein the typical conductive polymer poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) to be successfully modified onto single-walled carbon nanotubes (SWCNTs) using a supercritical carbon dioxide (SC CO2) antisolvent-induced polymer epitaxy method, and the role of the experimental temperature of SC CO2 on the modification process was systematically investigated. PEDOT:PSS/SWCNTs composites with optimal modification prepared at 80 °C and 15 MPa were used as functional fillers, and functional temperature-sensitive composite hydrogels of PEDOT:PSS/SWCNTs/poly-N-isopropylacrylamide (PNIPAM) were successfully prepared. With the help of Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and other characterization means, the chemical composition and microscopic morphology of the composite hydrogel were systematically analyzed. The composite hydrogel exhibits reversible temperature-sensitive responsiveness, transitioning from a transparent swollen state at room temperature to an opaque collapsed state at 32 °C, and demonstrates strong adhesion to various substrates, including glass, plastic, metal, and skin. Meanwhile, the near-infrared (NIR) photothermal conversion properties of this hydrogel were evaluated, showing a significant and uniform temperature increase upon NIR irradiation. The drug release behavior was assessed in vitro after loading the hydrophilic anticancer drug 5-fluorouracil (5-FU) with the stimulation of NIR light, achieving an accelerated and on-demand release. Our experimental results indicate that the pore size increases with the increase of the addition of PEDOT:PSS/SWCNTs, enabling the precise controlled release of 5-FU. This work provides new insights and experimental support for the design of intelligent drug delivery systems.

Renewable energy sources, such as solar and biomass, represent sustainable alternatives to meet the growing energy demands of the residential sector. This study evaluated the energy, exergy, and environmental performance of two Brayton configurations using supercritical carbon dioxide: a recompression cycle (SRC) and a recompression cycle with intercooling in the main compression (SMC), both coupled to a dual-loop organic Rankine cycle (DORC) and powered by a hybrid solar-biomass thermal system. Mass, energy, and exergy balances were developed, and a life cycle assessment was performed to quantify the environmental impact. The systems were designed to cover a cooling load of 130 kW corresponding to 200 dwellings constructed with Asbestos cement in the Colombian Caribbean region. The results show that both configurations meet the required demand; the SMC-DORC cycle operates at 650 °C, while the SRC-DORC requires 750 °C. The SRC-DORC exhibits higher thermal efficiency (53.24%), while the SMC-DORC achieves a slightly higher exergy efficiency (28.15%). Environmental analysis shows that the construction phase accounts for the majority of the total impact, exceeding 95% of emissions. Overall, both configurations are technically feasible, with the SRC-DORC standing out for its balance between efficiency and environmental impact.

Tomato seeds, a by-product of the tomato-processing industry, are a rich source of bioactive compounds with promising nutritional and functional potential. This study aimed to optimize the supercritical CO2 (SC-CO2) extraction of phenolic compounds from Solanum lycopersicum L. seeds using a Full Factorial Design (FFD) within the framework of Response Surface Methodology (RSM). The effects of extraction pressure (100-500 bar) and temperature (40-80 °C) were evaluated, with oil extraction yield and total phenolic content (TPC) as response variables. A one-factor-at-a-time (OFAT) approach assessed the effect of ethanol (0.25-1.0 mL) as a co-solvent under constant optimal extraction conditions. Derringer's desirability function was applied to identify simultaneous optimal conditions to maximize both responses. The main phenolic compounds were putatively annotated via high-performance liquid chromatography coupled with diode array detector and time-of-flight mass spectrometer (HPLC-DAD-TOF). Extraction pressure and co-solvent volume significantly affected both oil extraction yield and TPC, while temperature primarily influenced yield. Multi-response optimization achieved an overall desirability value of 1.0 at 425 bar and 78 °C with 1 mL ethanol, resulting the highest oil extraction yield and phenolic recovery. SC- CO2 extraction combined with desirability-based RSM is an efficient, green technique for valorizing tomato-processing residues, supporting circular bioeconomy principles through the sustainable recovery of high-value bioactives. Optimized SC-CO2 extraction using RSM revealed that the factors most influencing oil extraction yield and the recovery of phenolic compounds were pressure and the quantity of co-solvents used. HPLC-DAD-TOF analysis putatively annotated the main phenolic compounds, thus emphasizing the sustainable valorization of by-products from tomato processing.

Novel ingredients from rowanberry pomace were developed for French-type bread applications via supercritical CO2 extraction and the enzymatic and ultrasound treatment of the defatted residue (DFR), which contained 6.367% of proteins, 8.36% of soluble, and 43.04% insoluble fiber. Proteolytic enzymes from Bacillus licheniformis and Aspergillus oryzae, and cellulolytic enzyme mixtures Viscozyme L and Celuclast, were used to increase the soluble fraction. Treating DFR with enzymes generated significant amounts of soluble substances containing oligosaccharides, fructose, and glucose, with Viscozyme L being more effective than proteases. Tri-, and tetrapeptides, chlorogenic acids, and dihydroxy coumarins were also present in the soluble extracts of fermented DFR. The antioxidant characteristics of treated DFR were evaluated by the in vitro assays. Substitution of >5% of wheat flour with untreated DFR significantly reduced bread volume and crumb porosity; however, these adverse effects were mitigated by using fermented DFR. The highest bread volume (1845 cm3) and porosity (78.38%) were observed in bread containing 5% pomace that underwent enzymatic hydrolysis and ultrasound treatment. The substitution of flour with DFR significantly increased the antioxidant characteristics of bread samples and the substances generated during the in vitro digestion. It may be concluded that rowanberry pomace ingredients may improve bread nutritional quality and assist in the sustainable use of fruit processing by-products.

This paper proposes and evaluates a novel solar-assisted multigeneration plant integrating a partial-cooling and reheated supercritical carbon dioxide (sCO2) Brayton cycle (BC) with an organic Rankine cycle (ORC), vapor compression refrigeration cycle (VCRC), thermoelectric generators (TEG), and a PEM electrolyzer to simultaneously produce electricity, cooling, and hydrogen. A comprehensive thermodynamic, economic, and environmental assessment is carried out. Parametric analyses are performed by varying solar irradiation, the turbine high pressure, and the compressor inlet pressure of the sCO2 BC to quantify their influence on subsystem interactions, irreversibilities, efficiencies, and hydrogen production. Results show that increasing solar irradiation enhances BC power from 3248.93 to 3762.02 kW and cooling capacity from 989.72 to 2997.33 kW, while the high pressure improves both energy and exergy efficiencies and lowers levelized cost of electricity (LCOE) and levelized cost of hydrogen (LCOH). On the other hand, raising the low pressure lowers BC energy output and hydrogen production but boosts heat recovery in the bottoming cycle. A genetic algorithm (GA) is used for multi-objective optimization to lower the LCOE and raise the exergy efficiency at the same time. The best setup has an exergy efficiency of 35.11% and an LCOE of 0.0471 $/kWh.

ABSTRACT A comprehensive analysis of the composition and antioxidant activity of Chinese Kushui rose essential oil (KSEO) obtained by hydrodistillation and three absolutes prepared from concretes obtained by supercritical CO 2 extraction (KSSAA), petroleum ether extraction (KSPAA) and dichloromethane extraction (KSDAA), which were subsequently dewaxed with ethanol and distilled under atmospheric pressure, was conducted using gas chromatography–mass spectrometry (GC–MS) and sensory evaluation. A total of 156 volatile compounds were identified, among which 8 were common to all four extracts. Multivariate statistical analysis identified 84 key compounds with variable importance in projection (VIP) > 1. Sensory evaluation revealed that KSEO received the highest scores in odour intensity, complexity and overall liking, followed by KSSAA, whereas KSPAA and KSDAA were rated lower. Evaluation of antioxidant activity using DPPH and ABTS radical scavenging assays revealed that KSDAA exhibited the strongest comprehensive antioxidant activity. In conclusion, whereas the essential oil (KSEO) demonstrated superior sensory properties, the absolutes (particularly KSDAA) possessed enhanced antioxidant potential. This complementary functional profile may provide valuable guidance for selecting suitable Chinese Kushui rose aroma extracts for specific application.

Analysis and Optimization of Turbulent Prandtl Number in Supercritical CO2 Turbulent Flow Models Far from Pseudo-Critical Temperature

Wheat processing generates large volumes of co-products, particularly wheat bran (WB) and wheat germ (WG), which remain underutilized despite their high content of dietary fiber, phenolic compounds, bioactive peptides, and lipophilic antioxidants. Although their composition and processing have been widely investigated, an integrated and application-oriented evaluation of these fractions remains limited. This review provides a structured and critical analysis of WB, raw and defatted WG, and wheat germ oil (WGO), linking composition, processing strategies, and functional performance within a unified framework. Conventional and emerging technologies, including enzymatic hydrolysis, fermentation, thermomechanical treatments, and supercritical CO2 extraction, are discussed in terms of selectivity, impact on techno-functional properties, and scalability. An evidence-grading approach is introduced to distinguish bioactivities supported by chemical assays, cell-based models, animal studies, or human data, enabling a more rigorous interpretation of health-related effects. Across applications, these co-products have been incorporated into food systems and related sectors, primarily showing improvements in nutritional composition, oxidative stability, and product performance under experimental conditions. However, translation to an industrial scale remains constrained by techno-economic limitations, regulatory requirements, and stability challenges. This work highlights the need for integrated processing strategies aligned with industrial feasibility to support the development of sustainable cereal biorefineries.

This article presents a comprehensive research and development effort focused on the design of a vortex burner device intended to enable stable oxy fuel combustion of natural gas in a supercritical carbon dioxide (sCO2) environment, as used in the Allam cycle for zero emission power generation. The prototype burner, featuring a conical bluff body, was systematically analyzed using advanced numerical simulations incorporating detailed chemical kinetics. Optimization studies identified the most suitable combustion parameters, namely an oxidizer excess coefficient α = 1.05. This parameter choice is justified by the fact that it yields acceptable emissions of carbon monoxide (CO) and unburned hydrocarbons (UHC) while maintaining a reasonable level of auxiliary power consumption by the air separation unit (ASU). In the numerical investigation employing the prototype configuration, the maximum stable mass fraction of CO2 in the oxidizer diluent mixture (γ) was found to be 0.82, beyond which flame detachment occurred. Through iterative design enhancements—specifically, replacing the conical bluff body with a hemispherical perforated bluff body and incorporating a diffuser-shaped outlet section—the burner configuration was substantially improved. These modifications enhanced flame stability and enabled a significant increase in γ to 0.867. As a result, the peak process temperature was reduced by more than 400 K, while CO emissions decreased by over a factor of 17 compared to the prototype, with unburned hydrocarbon levels remaining low.