Pub Date : 2025-02-10DOI: 10.1016/j.supflu.2025.106546
Andri Swanepoel , Philip W. Labuschagne , Cara E. Schwarz
Melting temperature, phase behaviour and densities of binary mixtures of CO2 and three Fischer-Tropsch waxes with varying molecular weights were experimentally determined. The melting temperatures of the lower molecular weight waxes increased with CO2 pressure, and pressure induced crystallisation of the lowest molecular weight wax occurred above 20 MPa. CO2 solubility in the waxes decreased with increasing wax molecular weight. Trends in mixture densities with changes in temperature and pressure mimicked that of pure CO2. The viscosity of the lowest molecular weight wax decreased with increased CO2 concentration, and decreased with increases in temperature and pressure, with the impact of pressure minimised above the temperature inversion point. Solubility data were correlated with a modified Chrastil and the Mendez-Santiago & Teja models. The Chrastil model accurately predicted solubility of CO2 in all three waxes to within 1 % of the measured values.
{"title":"Measurement of phase transition, density and viscosity of supercritical carbon dioxide-Fischer-Tropsch wax mixtures","authors":"Andri Swanepoel , Philip W. Labuschagne , Cara E. Schwarz","doi":"10.1016/j.supflu.2025.106546","DOIUrl":"10.1016/j.supflu.2025.106546","url":null,"abstract":"<div><div>Melting temperature, phase behaviour and densities of binary mixtures of CO<sub>2</sub> and three Fischer-Tropsch waxes with varying molecular weights were experimentally determined. The melting temperatures of the lower molecular weight waxes increased with CO<sub>2</sub> pressure, and pressure induced crystallisation of the lowest molecular weight wax occurred above 20 MPa. CO<sub>2</sub> solubility in the waxes decreased with increasing wax molecular weight. Trends in mixture densities with changes in temperature and pressure mimicked that of pure CO<sub>2</sub>. The viscosity of the lowest molecular weight wax decreased with increased CO<sub>2</sub> concentration, and decreased with increases in temperature and pressure, with the impact of pressure minimised above the temperature inversion point. Solubility data were correlated with a modified Chrastil and the Mendez-Santiago & Teja models. The Chrastil model accurately predicted solubility of CO<sub>2</sub> in all three waxes to within 1 % of the measured values.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"220 ","pages":"Article 106546"},"PeriodicalIF":3.4,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-07DOI: 10.1016/j.supflu.2025.106543
Wei Xiong , Lie-Hui Zhang , Yu-Long Zhao , Shao-Mu Wen , Li-Li Liu , Zheng-Lin Cao , Yong-Chao Wang , Shan-Gui Luo , Xian-Yu Jiang
Accurate derivatives are required for simulating large-scale carbon dioxide (CO2) geological storage using the Cubic-Plus-Association equation of state (CPA EoS). However, due to the mathematical implicitness of cross-association, calculating the correct derivatives of site fractions for cross-association mixtures is extremely difficult and computationally demanding. A general explicit formulation of cross-association for different bonding types is presented. The non-bonded fraction of cross-associating molecules is obtained from the non-bonded fraction of self-associating molecules without cross-association. This approach eliminates the circular iterative process and improves computational efficiency. The overall CPU time decreases by 70 % for flash calculations and compositional simulations. The modeling capability of CPA is extended to H2O-CO2-H2S-N2-O2-Ar-SO2-CH4-C2H6-C3H8 mixtures. Results indicate that CPA can accurately predict the phase behavior of binary CO2 capture, utilization, and storage (CCUS) mixtures. This study provides a modified CPA EoS, applicable to most of the currently treated CCUS fluids, and discusses its strengths and limitations.
{"title":"Phase equilibrium modeling for CCUS fluids using a modified association equation of state","authors":"Wei Xiong , Lie-Hui Zhang , Yu-Long Zhao , Shao-Mu Wen , Li-Li Liu , Zheng-Lin Cao , Yong-Chao Wang , Shan-Gui Luo , Xian-Yu Jiang","doi":"10.1016/j.supflu.2025.106543","DOIUrl":"10.1016/j.supflu.2025.106543","url":null,"abstract":"<div><div>Accurate derivatives are required for simulating large-scale carbon dioxide (CO<sub>2</sub>) geological storage using the Cubic-Plus-Association equation of state (CPA EoS). However, due to the mathematical implicitness of cross-association, calculating the correct derivatives of site fractions for cross-association mixtures is extremely difficult and computationally demanding. A general explicit formulation of cross-association for different bonding types is presented. The non-bonded fraction of cross-associating molecules is obtained from the non-bonded fraction of self-associating molecules without cross-association. This approach eliminates the circular iterative process and improves computational efficiency. The overall CPU time decreases by 70 % for flash calculations and compositional simulations. The modeling capability of CPA is extended to H<sub>2</sub>O-CO<sub>2</sub>-H<sub>2</sub>S-N<sub>2</sub>-O<sub>2</sub>-Ar-SO<sub>2</sub>-CH<sub>4</sub>-C<sub>2</sub>H<sub>6</sub>-C<sub>3</sub>H<sub>8</sub> mixtures. Results indicate that CPA can accurately predict the phase behavior of binary CO<sub>2</sub> capture, utilization, and storage (CCUS) mixtures. This study provides a modified CPA EoS, applicable to most of the currently treated CCUS fluids, and discusses its strengths and limitations.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"219 ","pages":"Article 106543"},"PeriodicalIF":3.4,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, salicin, the key active ingredient in willow bark and a primary source of aspirin, was extracted using supercritical CO₂. Gas chromatography (GC) characterized the extract. Key operating factors, including pressure, temperature, particle size, and extraction time, were varied to optimize extraction yield, employing response surface methodology (RSM) with a central composite design (CCD) method. The maximum yield was 12.371 % (mass of extracted salicin / mass of dry willow bark) with a 56.75 % salicin recovery under the optimal condition, determined as 22 MPa pressure, 40 °C temperature, 0.45 mm particle size, and 100 minutes extraction time. Results showed that higher extraction time and pressure increased yield, while temperature and particle size reduced it. Extraction time had the most significant effect, while temperature was the least impactful. The Sovová and Tan and Liou models were applied, showing close agreement between predicted and experimental extraction curves.
{"title":"Supercritical extraction of salicin, aspirin precursor, from the willow bark, laboratory optimization via response surface methodology and mathematical modeling","authors":"Mohammad Abohassan , Normurot Fayzullaev , Gaber Edris , Subasini Uthirapathy , Gaurav Sanghvi , Naga Bhushana Rao Vakada , Swati Sharma , Prashant Nakash , Yasser Fakri Mustafa , Maythum Ali Shallan","doi":"10.1016/j.supflu.2025.106540","DOIUrl":"10.1016/j.supflu.2025.106540","url":null,"abstract":"<div><div>In this study, salicin, the key active ingredient in willow bark and a primary source of aspirin, was extracted using supercritical CO₂. Gas chromatography (GC) characterized the extract. Key operating factors, including pressure, temperature, particle size, and extraction time, were varied to optimize extraction yield, employing response surface methodology (RSM) with a central composite design (CCD) method. The maximum yield was 12.371 % (mass of extracted salicin / mass of dry willow bark) with a 56.75 % salicin recovery under the optimal condition, determined as 22 MPa pressure, 40 °C temperature, 0.45 mm particle size, and 100 minutes extraction time. Results showed that higher extraction time and pressure increased yield, while temperature and particle size reduced it. Extraction time had the most significant effect, while temperature was the least impactful. The Sovová and Tan and Liou models were applied, showing close agreement between predicted and experimental extraction curves.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"219 ","pages":"Article 106540"},"PeriodicalIF":3.4,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The molecular structures of thermoplastic polyurethane (TPU) affect its microphase separation and foaming behavior. Three aliphatic TPUs were studied to investigate the influence of their molecular structures on their crystallization behavior, shear rheological properties, mechanical properties, and foaming behavior. The experimental results indicated that the branched structure and hard segment content affected the crystallization behavior of TPU. Lower crystallinity decreased the foaming initiation temperature, whereas higher crystallinity enhanced the stability of cell structure. The branched structure and hard segment domains functioned as heterogeneous nucleation sites, leading to increased cell density and reduced cell size in microcellular TPU. Microcellular TPU with a high molecular weight and branched structure exhibited superior tensile strength and elongation at break, i.e., the tensile strength and elongation at break of TPU1 with a density of 0.25 g/cm3 reached 10.82 MPa and 373 %, respectively. This study demonstrated the regulation of microcellular TPU by analyzing its molecular structures.
{"title":"Supercritical CO2 foaming and mechanical properties of thermoplastic polyurethane based on molecular structure","authors":"Chenyang Niu, Xiulu Gao, Yichong Chen, Weizhen Sun, Ling Zhao, Dongdong Hu","doi":"10.1016/j.supflu.2025.106541","DOIUrl":"10.1016/j.supflu.2025.106541","url":null,"abstract":"<div><div>The molecular structures of thermoplastic polyurethane (TPU) affect its microphase separation and foaming behavior. Three aliphatic TPUs were studied to investigate the influence of their molecular structures on their crystallization behavior, shear rheological properties, mechanical properties, and foaming behavior. The experimental results indicated that the branched structure and hard segment content affected the crystallization behavior of TPU. Lower crystallinity decreased the foaming initiation temperature, whereas higher crystallinity enhanced the stability of cell structure. The branched structure and hard segment domains functioned as heterogeneous nucleation sites, leading to increased cell density and reduced cell size in microcellular TPU. Microcellular TPU with a high molecular weight and branched structure exhibited superior tensile strength and elongation at break, i.e., the tensile strength and elongation at break of TPU1 with a density of 0.25 g/cm<sup>3</sup> reached 10.82 MPa and 373 %, respectively. This study demonstrated the regulation of microcellular TPU by analyzing its molecular structures.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"219 ","pages":"Article 106541"},"PeriodicalIF":3.4,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143228086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1016/j.supflu.2025.106542
EK Anagha , R. Sariga , K. ShyamSundar , Rames C. Panda , M. Helen Kalavathy , S.N. Naik
Background
Tallow, a by-product of the leather-industry, is widely used in pharmaceuticals and oleochemical applications as a source/precursor of glycerol, obtained by aqueous-hydrolysis under high-pressure-temperature from a hydrolyzing-tower. Though standard procedures of extracting glycerol from the bottom-product are well established, the purification of fatty-acids (FA) from the top crude-mixture needs attention
Method
This paper identifies and separates individual fatty-acids from the Twitchell-process using the supercritical-fluid-extraction (SFE). Solubilities (Soave-Redlich-Kwong) and phase-diagrams are obtained using Matlab & Aspen, respectively. The characteristics of the product are analyzed by mass-spectroscopy which reveals that the FA-components present in the crude-mixture in the ratio of 4.3:32.2:43.0:20.4 for C-14, C16, C16 = 2, and C18 components respectively are more efficiently extracted by the solvent of SFE compared to CH3OH solvent
Findings
It has been found from the analysis and characterization that the rate of extraction is improved by 2–3 times in case of saturated while it’s about 9 times in-case-of unsaturated FA compared to the nominal method of extraction. Addition of ionic-liquid (IL) with SFE-solvent improved the solubility to 92 %. A model is formulated to validate the findings. It is suggested that the pure components extracted by SFE assisted by IL can be used for the preparation of oleochemicals in further downstream-processing.
{"title":"Supercritical CO2 assisted extraction, purification and modelling of free fatty acids from the crude mixture – A case study of tallow hydrolysis","authors":"EK Anagha , R. Sariga , K. ShyamSundar , Rames C. Panda , M. Helen Kalavathy , S.N. Naik","doi":"10.1016/j.supflu.2025.106542","DOIUrl":"10.1016/j.supflu.2025.106542","url":null,"abstract":"<div><h3>Background</h3><div>Tallow, a by-product of the leather-industry, is widely used in pharmaceuticals and oleochemical applications as a source/precursor of glycerol, obtained by aqueous-hydrolysis under high-pressure-temperature from a hydrolyzing-tower. Though standard procedures of extracting glycerol from the bottom-product are well established, the purification of fatty-acids (FA) from the top crude-mixture needs attention</div></div><div><h3>Method</h3><div>This paper identifies and separates individual fatty-acids from the Twitchell-process using the supercritical-fluid-extraction (SFE). Solubilities (Soave-Redlich-Kwong) and phase-diagrams are obtained using Matlab & Aspen, respectively. The characteristics of the product are analyzed by mass-spectroscopy which reveals that the FA-components present in the crude-mixture in the ratio of 4.3:32.2:43.0:20.4 for C-14, C16, C16 = 2, and C18 components respectively are more efficiently extracted by the solvent of SFE compared to CH<sub>3</sub>OH solvent</div></div><div><h3>Findings</h3><div>It has been found from the analysis and characterization that the rate of extraction is improved by 2–3 times in case of saturated while it’s about 9 times in-case-of unsaturated FA compared to the nominal method of extraction. Addition of ionic-liquid (IL) with SFE-solvent improved the solubility to 92 %. A model is formulated to validate the findings. It is suggested that the pure components extracted by SFE assisted by IL can be used for the preparation of oleochemicals in further downstream-processing.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"219 ","pages":"Article 106542"},"PeriodicalIF":3.4,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-03DOI: 10.1016/j.supflu.2024.106508
Maria N.H. Cupaja , Camila Guindani , Frederico W. Tavares , Papa M. Ndiaye
Propane is considered an alternative in enzymatic polyester synthesis due to its favorable enzymatic interactions and mild operating pressures. In this study, enzymatic polymerizations were carried out by ring-opening polymerization of the monomer globalide at 65 °C, using pressurized propane as solvent. Mass ratios of propane:globalide of 1:2, 1:1, and 2:1 were evaluated, as well as pressure conditions of 30, 70, 110, and 150 bar. The enzyme concentration was kept at 5 % relative to globalide mass, with a fixed reaction time of two hours. Results showed monomer conversions up to 93 % and molecular weights ranging from 17.5 kDa to 125.9 kDa, surpassing those with pressurized CO2. Working pressure had an effect in monomer conversion, suggesting that both the increase in propane viscosity as well as the confinement of the system (compressibility) play important roles in the reaction, but depending on the working pressure, one of the effects will be dominant.
{"title":"Effect of pressure and monomer concentration on ring-opening enzymatic polymerization of globalide in pressurized propane","authors":"Maria N.H. Cupaja , Camila Guindani , Frederico W. Tavares , Papa M. Ndiaye","doi":"10.1016/j.supflu.2024.106508","DOIUrl":"10.1016/j.supflu.2024.106508","url":null,"abstract":"<div><div>Propane is considered an alternative in enzymatic polyester synthesis due to its favorable enzymatic interactions and mild operating pressures. In this study, enzymatic polymerizations were carried out by ring-opening polymerization of the monomer globalide at 65 °C, using pressurized propane as solvent. Mass ratios of propane:globalide of 1:2, 1:1, and 2:1 were evaluated, as well as pressure conditions of 30, 70, 110, and 150 bar. The enzyme concentration was kept at 5 % relative to globalide mass, with a fixed reaction time of two hours. Results showed monomer conversions up to 93 % and molecular weights ranging from 17.5 kDa to 125.9 kDa, surpassing those with pressurized CO<sub>2</sub>. Working pressure had an effect in monomer conversion, suggesting that both the increase in propane viscosity as well as the confinement of the system (compressibility) play important roles in the reaction, but depending on the working pressure, one of the effects will be dominant.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"220 ","pages":"Article 106508"},"PeriodicalIF":3.4,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-02DOI: 10.1016/j.supflu.2025.106539
Mohammed A. Al-Hakami , Ahmed Farid Ibrahim , Khaled Z. Abdelgawad
Innovation and sustainability are critical for maximizing reserves in the petroleum industry, especially in deep heavy oil reservoirs where traditional thermal EOR techniques often underperform. CO2-flooding offers a promising alternative, with its effectiveness dependent on achieving minimum miscibility pressure (MMP). Reducing MMP offers higher recovery factors while avoiding issues due to formation fracturing at high injection pressures. This study evaluates ionic liquids (ILs), 1-methyl-3-octylimidazolium chloride ([MOIM]Cl) and 1-decyl-3-methylimidazolium chloride ([DMIM]Cl), for lowering MMP in CO2-crude oil systems. Results showed [MOIM]Cl and [DMIM]Cl reduced MMP by 17 % and 13.5 %, outperforming n-butanol and non-ionic surfactants, which achieved 6 % and 9 % reductions, respectively. For extra heavy oil, [MOIM]Cl reduced MMP by 15.5 %. The ILs also lowered first contact miscibility pressure across crude oils with asphaltene content ranging from 6.4 to 36 wt%. These findings highlight ILs' potential to improve CO2 miscibility in heavy oil reservoirs, providing a sustainable solution for enhanced oil recovery.
{"title":"Applications of ionic liquids in improving CO2 miscibility in crude oil for enhanced oil recovery and CO2 sequestration applications","authors":"Mohammed A. Al-Hakami , Ahmed Farid Ibrahim , Khaled Z. Abdelgawad","doi":"10.1016/j.supflu.2025.106539","DOIUrl":"10.1016/j.supflu.2025.106539","url":null,"abstract":"<div><div>Innovation and sustainability are critical for maximizing reserves in the petroleum industry, especially in deep heavy oil reservoirs where traditional thermal EOR techniques often underperform. CO<sub>2</sub>-flooding offers a promising alternative, with its effectiveness dependent on achieving minimum miscibility pressure (MMP). Reducing MMP offers higher recovery factors while avoiding issues due to formation fracturing at high injection pressures. This study evaluates ionic liquids (ILs), 1-methyl-3-octylimidazolium chloride ([MOIM]Cl) and 1-decyl-3-methylimidazolium chloride ([DMIM]Cl), for lowering MMP in CO<sub>2</sub>-crude oil systems. Results showed [MOIM]Cl and [DMIM]Cl reduced MMP by 17 % and 13.5 %, outperforming n-butanol and non-ionic surfactants, which achieved 6 % and 9 % reductions, respectively. For extra heavy oil, [MOIM]Cl reduced MMP by 15.5 %. The ILs also lowered first contact miscibility pressure across crude oils with asphaltene content ranging from 6.4 to 36 wt%. These findings highlight ILs' potential to improve CO<sub>2</sub> miscibility in heavy oil reservoirs, providing a sustainable solution for enhanced oil recovery.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"219 ","pages":"Article 106539"},"PeriodicalIF":3.4,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143168307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-29DOI: 10.1016/j.supflu.2025.106538
Alican Ertas, Cerag Dilek
The solubility of a bifunctional polyhedral oligomeric silsesquioxane, trifluoropropylisobutyl (TFIB) POSS, in supercritical carbon dioxide (scCO2) was investigated. In the temperature and pressure ranges of 308 K to 323 K and 8.8 MPa to 14.5 MPa, respectively, TFIB POSS is soluble in scCO2 up to 2.0 × 10−2 by weight fraction corresponding to 1.0 × 10−3 by mole fraction, which is between the solubility of its monofunctional counterparts, octaisobutyl POSS and octatrifluoropropyl POSS. The study includes the modeling of the TFIB POSS-CO2 binary system phase equilibrium with the density-based semi-empirical equations and Peng Robinson+COSMO segment activity coefficient (PR+COSMOSAC) equation of state (EOS). The prediction of the equation of state has been improved for the cage-structured molecule by introducing new electrostatic and dispersion contributions. While the density-based relations provide better fits to the solubility isotherms, the main advantage of the EOS is its applicability for a priori phase equilibrium predictions for the CO2-POSS systems in the absence of the solute critical properties.
{"title":"High-pressure phase behavior of the carbon dioxide-trifluoropropylisobutyl polyhedral oligomeric silsesquioxane binary system","authors":"Alican Ertas, Cerag Dilek","doi":"10.1016/j.supflu.2025.106538","DOIUrl":"10.1016/j.supflu.2025.106538","url":null,"abstract":"<div><div>The solubility of a bifunctional polyhedral oligomeric silsesquioxane, trifluoropropylisobutyl (TFIB) POSS, in supercritical carbon dioxide (scCO<sub>2</sub>) was investigated. In the temperature and pressure ranges of 308 K to 323 K and 8.8 MPa to 14.5 MPa, respectively, TFIB POSS is soluble in scCO<sub>2</sub> up to 2.0 × 10<sup>−2</sup> by weight fraction corresponding to 1.0 × 10<sup>−3</sup> by mole fraction, which is between the solubility of its monofunctional counterparts, octaisobutyl POSS and octatrifluoropropyl POSS. The study includes the modeling of the TFIB POSS-CO<sub>2</sub> binary system phase equilibrium with the density-based semi-empirical equations and Peng Robinson+COSMO segment activity coefficient (PR+COSMOSAC) equation of state (EOS). The prediction of the equation of state has been improved for the cage-structured molecule by introducing new electrostatic and dispersion contributions. While the density-based relations provide better fits to the solubility isotherms, the main advantage of the EOS is its applicability for a priori phase equilibrium predictions for the CO<sub>2</sub>-POSS systems in the absence of the solute critical properties.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"219 ","pages":"Article 106538"},"PeriodicalIF":3.4,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143228559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-28DOI: 10.1016/j.supflu.2025.106537
Yan Ren , Le Zeng , Shaogeng Zhong , Weidong Wu , Yingying Yang , Qiguo Yang
To improve the performance of printed circuit heat exchanger (PCHE) in the supercritical carbon dioxide (SCO2) Brayton cycle system, the mathematic-physical model of the heat exchange unit was established, based on a new-type rectangular microchannel PCHE (RM-PCHE) manufacturing by total-etching technology in this study. And the influence mechanism and laws on the flow and heat transfer of the different fin distributions and shapes were numerically investigate. Results showed average simulation deviations of 0.9 % for outlet temperature and 13.3 % for heat transfer quantity, meeting accuracy requirement. Uniform fin distribution at 10 mm intervals significantly reduced pressure drop and improved comprehensive heat transfer performance by 14.8 %. When elliptical and airfoil fins were selected for the hot-side and cold-side channels, the flow characteristic significantly improved and the heat transfer process became more stable, improving the single-side performance by 15.9 % and 12.3 %, respectively.
{"title":"Optimization of fin for rectangular microchannel printed circuit heat exchanger using supercritical CO2 as working fluid","authors":"Yan Ren , Le Zeng , Shaogeng Zhong , Weidong Wu , Yingying Yang , Qiguo Yang","doi":"10.1016/j.supflu.2025.106537","DOIUrl":"10.1016/j.supflu.2025.106537","url":null,"abstract":"<div><div>To improve the performance of printed circuit heat exchanger (PCHE) in the supercritical carbon dioxide (SCO<sub>2</sub>) Brayton cycle system, the mathematic-physical model of the heat exchange unit was established, based on a new-type rectangular microchannel PCHE (RM-PCHE) manufacturing by total-etching technology in this study. And the influence mechanism and laws on the flow and heat transfer of the different fin distributions and shapes were numerically investigate. Results showed average simulation deviations of 0.9 % for outlet temperature and 13.3 % for heat transfer quantity, meeting accuracy requirement. Uniform fin distribution at 10 mm intervals significantly reduced pressure drop and improved comprehensive heat transfer performance by 14.8 %. When elliptical and airfoil fins were selected for the hot-side and cold-side channels, the flow characteristic significantly improved and the heat transfer process became more stable, improving the single-side performance by 15.9 % and 12.3 %, respectively.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"219 ","pages":"Article 106537"},"PeriodicalIF":3.4,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143168309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-21DOI: 10.1016/j.supflu.2025.106523
Xiao-Chang Lu , Biao-Qi Chen , Sheng-Qing Li , Jian-Fei Xu , Ranjith Kumar Kankala , Shi-Bin Wang , Ai-Zheng Chen
The poor water solubility of hesperetin (HST) has impeded its relevant medical applications. To address this problem, the supercritical anti-solvent (SAS) technique was used to prepare HST-polyvinylpyrrolidone (HST-PVP) sub-microparticles. Additionally, the Box-Behnken Design was used to optimize three parameters (temperature, total solute concentration, and pressure) to determine the optimal process conditions, which were determined to be 40 ℃, 5 mg/mL, and 100 bar. The physicochemical properties, drug release, and in vitro anti-cancer efficacy of the designed particles under the optimal conditions were systematically investigated. The drug loading of HST in HST-PVP sub-microparticles was quantified at 12.73 %. The dissolution rate of SAS-treated HST-PVP sub-microparticles was significantly enhanced compared to that of pure HST, leading to a higher anti-cancer efficiency of the HST-PVP sub-microparticles than that of pure HST. These findings indicate that the SAS technique holds significant potential for enhancing the bioavailability of hydrophobic drugs.
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