Pub Date : 2024-12-16DOI: 10.1016/j.supflu.2024.106496
Govind Dubey, Prabu Vairakannu, Pankaj Tiwari
The present research aimed at the direct coal liquefaction (DCL) of three Indian coals with toluene and Fe2O3 catalyst within a temperature range of 400 ℃- 450 °C. The maximum overall conversion of 41.87 wt% and oil yield of 16.25 wt% was observed for lignite coal, at 60 min residence time and 450 ℃ for catalytic, with an increase of 6 % and 4.72 %, respectively, compared to that of thermal liquefaction. The activation energies were in the 40 kJ/mol to 370 kJ/mol range. The CO2 levels peaked at 15.45 vol% for catalytic and 11.18 vol% for thermal DCL in the case of lignite coal. The hydrogen sulfide and carbonyl sulfide gases with maximum concentrations of 563 ppm and 230 ppm, respectively, were also detected. The oil possesses carbon chains ranging from C8 to C25, whereas both asphaltene and preasphaltene fractions extend to a broader range of C8-C30.
{"title":"Study of mechanism, kinetics, and product characterization of thermal and catalytic liquefaction of Northeastern Indian coals using supercritical toluene","authors":"Govind Dubey, Prabu Vairakannu, Pankaj Tiwari","doi":"10.1016/j.supflu.2024.106496","DOIUrl":"10.1016/j.supflu.2024.106496","url":null,"abstract":"<div><div>The present research aimed at the direct coal liquefaction (DCL) of three Indian coals with toluene and Fe<sub>2</sub>O<sub>3</sub> catalyst within a temperature range of 400 ℃- 450 °C. The maximum overall conversion of 41.87 wt% and oil yield of 16.25 wt% was observed for lignite coal, at 60 min residence time and 450 ℃ for catalytic, with an increase of 6 % and 4.72 %, respectively, compared to that of thermal liquefaction. The activation energies were in the 40 kJ/mol to 370 kJ/mol range. The CO<sub>2</sub> levels peaked at 15.45 vol% for catalytic and 11.18 vol% for thermal DCL in the case of lignite coal. The hydrogen sulfide and carbonyl sulfide gases with maximum concentrations of 563 ppm and 230 ppm, respectively, were also detected. The oil possesses carbon chains ranging from C<sub>8</sub> to C<sub>25</sub>, whereas both asphaltene and preasphaltene fractions extend to a broader range of C<sub>8</sub>-C<sub>30</sub>.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106496"},"PeriodicalIF":3.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874112","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 : 2024-12-15DOI: 10.1016/j.supflu.2024.106497
Yu Su , Qingxin Zheng , Yoshiki Suga , Masaru Watanabe
Here, the solubility of terephthalic acid (TPA) in water was measured under hydrothermal conditions at temperatures from 423.15 K to 623.15 K by a semi-dynamic gravimetric system. The whole process, using water as the only solvent, was considered safe and environmentally friendly. The results indicated that the TPA solubility in water increased exponentially with the temperature. Particularly, at 573.15 K (10 MPa) and 623.15 K (20 MPa), the water solubility of TPA was measured to be 108.1 and 347.4 g kg−1, respectively. It was the first time to measure the TPA solubility in water at over 523.15 K experimentally. Fitted curves for the TPA solubility in water as functions of temperature and water density were plotted, and the thermodynamic properties for the dissolution of TPA into water were obtained and plotted. The TPA solubility results obtained would be helpful to improve the production or recycling of TPA under hydrothermal conditions.
{"title":"Measurement of solubility of terephthalic acid in water under hydrothermal conditions","authors":"Yu Su , Qingxin Zheng , Yoshiki Suga , Masaru Watanabe","doi":"10.1016/j.supflu.2024.106497","DOIUrl":"10.1016/j.supflu.2024.106497","url":null,"abstract":"<div><div>Here, the solubility of terephthalic acid (TPA) in water was measured under hydrothermal conditions at temperatures from 423.15 K to 623.15 K by a semi-dynamic gravimetric system. The whole process, using water as the only solvent, was considered safe and environmentally friendly. The results indicated that the TPA solubility in water increased exponentially with the temperature. Particularly, at 573.15 K (10 MPa) and 623.15 K (20 MPa), the water solubility of TPA was measured to be 108.1 and 347.4 g kg<sup>−1</sup>, respectively. It was the first time to measure the TPA solubility in water at over 523.15 K experimentally. Fitted curves for the TPA solubility in water as functions of temperature and water density were plotted, and the thermodynamic properties for the dissolution of TPA into water were obtained and plotted. The TPA solubility results obtained would be helpful to improve the production or recycling of TPA under hydrothermal conditions.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106497"},"PeriodicalIF":3.4,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874116","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 : 2024-12-12DOI: 10.1016/j.supflu.2024.106495
Jiquan Chen , Zitao Lin , Xingying Tang , Ke Li , Riguang Zhu , Jianqiao Yang
This paper presents a comparative study of the corrosion behavior of Inconel 625 in supercritical water with different oxygen contents and phosphate phases. The results showed that the dissolved phosphate phase could compete with oxygen and that the addition of oxygen converted Cr2O3 to Cr6 +, resulting in a reduction in the thickness of the oxide film. The oxide film formed consisted of three distinct layers. The outer layer consists of NiO, Fe2O3, and NiFe2O4, which were formed by the diffusion of metal cations outward. The middle layer was a metal phosphate passivation layer which could prevent the diffusion of Fe, Ni, etc. and retard corrosion. The inner layer was formed by inward oxidation of oxygen ions with Cr to form Cr2O3. Phosphate molten salt were highly corrosive and can directly dissolve Cr2O3 into soluble Cr3+, a process accelerated by oxygen, increasing the Cr3+ content from 59.63 % to 77.54 %.
{"title":"Comparative study of the corrosion behavior of Inconel 625 in supercritical water containing dissolved and molten phosphates","authors":"Jiquan Chen , Zitao Lin , Xingying Tang , Ke Li , Riguang Zhu , Jianqiao Yang","doi":"10.1016/j.supflu.2024.106495","DOIUrl":"10.1016/j.supflu.2024.106495","url":null,"abstract":"<div><div>This paper presents a comparative study of the corrosion behavior of Inconel 625 in supercritical water with different oxygen contents and phosphate phases. The results showed that the dissolved phosphate phase could compete with oxygen and that the addition of oxygen converted Cr<sub>2</sub>O<sub>3</sub> to Cr<sup>6 +</sup>, resulting in a reduction in the thickness of the oxide film. The oxide film formed consisted of three distinct layers. The outer layer consists of NiO, Fe<sub>2</sub>O<sub>3</sub>, and NiFe<sub>2</sub>O<sub>4</sub>, which were formed by the diffusion of metal cations outward. The middle layer was a metal phosphate passivation layer which could prevent the diffusion of Fe, Ni, etc. and retard corrosion. The inner layer was formed by inward oxidation of oxygen ions with Cr to form Cr<sub>2</sub>O<sub>3</sub>. Phosphate molten salt were highly corrosive and can directly dissolve Cr<sub>2</sub>O<sub>3</sub> into soluble Cr<sup>3+</sup>, a process accelerated by oxygen, increasing the Cr<sup>3+</sup> content from 59.63 % to 77.54 %.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106495"},"PeriodicalIF":3.4,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874113","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}
A supercritical CO2 (sCO2) supersonic ejector improves the coefficient of performance (COP) in combined power and cooling systems by compressing a secondary stream through entrainment and mixing with a high-momentum primary stream. The performance of the ejector is crucial to system efficiency and is influenced by complex gas dynamic shock interactions and shear layers which is further complicated by the rapid variations in thermophysical of sCO2. In this regard, aerodynamic duct shaping plays a pivotal role in optimizing ejector efficiency. The present paper seeks to optimize a sCO2 ejector using a surrogate model derived from computational fluid dynamics data. The model relies on a comprehensive dataset generated using a simulation tool coupled with REFPROP database to account for variations in thermophysical properties of sCO2. Subsequently, a genetic aggregation technique is used to train and improve the model via supervised machine learning. The influence of critical design parameters such as radius of mixing section, nozzle exit point, and mixing duct length on the performance of the ejector is enabled by a sensitivity analysis study facilitated by design space exploration. Finally, a multi-objective evolutionary algorithm is incorporated in the surrogate model to optimize the ejector performance by maximizing entrainment ratio and compression ratio, while minimizing entropy generation. It is found that stagnation temperature ratio is a key influencing parameter responsible for enhancing mixing layer growth to improve the ejector performance. The optimized ejector shows an enhanced efficiency of ∼ 25 % compared to a non-optimized ejector.
{"title":"Surrogate model based multi-objective optimisation of supercritical CO2 ejectors","authors":"Sanjoy Paul , R.P. Srikar , Srisha MV Rao , Pramod Kumar","doi":"10.1016/j.supflu.2024.106493","DOIUrl":"10.1016/j.supflu.2024.106493","url":null,"abstract":"<div><div>A supercritical CO<sub>2</sub> (sCO<sub>2</sub>) supersonic ejector improves the coefficient of performance (COP) in combined power and cooling systems by compressing a secondary stream through entrainment and mixing with a high-momentum primary stream. The performance of the ejector is crucial to system efficiency and is influenced by complex gas dynamic shock interactions and shear layers which is further complicated by the rapid variations in thermophysical of sCO<sub>2</sub>. In this regard, aerodynamic duct shaping plays a pivotal role in optimizing ejector efficiency. The present paper seeks to optimize a sCO<sub>2</sub> ejector using a surrogate model derived from computational fluid dynamics data. The model relies on a comprehensive dataset generated using a simulation tool coupled with REFPROP database to account for variations in thermophysical properties of sCO<sub>2</sub>. Subsequently, a genetic aggregation technique is used to train and improve the model via supervised machine learning. The influence of critical design parameters such as radius of mixing section, nozzle exit point, and mixing duct length on the performance of the ejector is enabled by a sensitivity analysis study facilitated by design space exploration. Finally, a multi-objective evolutionary algorithm is incorporated in the surrogate model to optimize the ejector performance by maximizing entrainment ratio and compression ratio, while minimizing entropy generation. It is found that stagnation temperature ratio is a key influencing parameter responsible for enhancing mixing layer growth to improve the ejector performance. The optimized ejector shows an enhanced efficiency of ∼ 25 % compared to a non-optimized ejector.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106493"},"PeriodicalIF":3.4,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874114","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 : 2024-12-12DOI: 10.1016/j.supflu.2024.106492
Lorena I. Jaramillo , Jalloul Bouajila , Edwin Vera , Séverine Camy
Sunfo volatile compounds (VC) were obtained by supercritical fluid extraction (SFE). The influence of temperature (40−60) °C, particle size (0.35–1) mm, flowrate (10−20) g/min and pressure (10−60) MPa on the yield was investigated. Composition, yield, antioxidant activity (AA) and total phenolic content (TPC) were compared with ultrasound assisted extraction (UAE), hydrodistillation (HD) and Soxhlet (SX). Extraction yields and major compounds obtained were: HD: 23.7 mg/g, thymol; SX: 244 mg/g, caryophyllene; 3′-hydroxyb-naphtoflavone; UAE: 227 mg/g, carvacrol, (z)-3-(3-ethoxy-4-hydroxy-phenyl)-2-phenylacrylic acid; SFE: 38.50 mg/g, thymol, carvacrol, (+-)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, 5-hydroxyflavone and icarrin. SX presented better AA (IC50-DPPH =19.60 mg/mL) followed by UAE (IC50- DPPH =48.13 mg/mL) and HD better TPC (184.07 mg GAE/g). Antifungal activity against Colletotrichum musae, Mucor racemosus and Fusarium verticillioides was assessed, minimal inhibitory concentration (MIC) was obtained. VC obtained had the most active antifungal activity against fungus (MIC: (400, 400, 825) mg/L).
{"title":"Influence of process parameters on yield, chemical composition and biological activities of Clinopodium nubigenum (Kunth) Kuntze (sunfo) extracts obtained by supercritical CO2 extraction and other techniques","authors":"Lorena I. Jaramillo , Jalloul Bouajila , Edwin Vera , Séverine Camy","doi":"10.1016/j.supflu.2024.106492","DOIUrl":"10.1016/j.supflu.2024.106492","url":null,"abstract":"<div><div>Sunfo volatile compounds (VC) were obtained by supercritical fluid extraction (SFE). The influence of temperature (40−60) °C, particle size (0.35–1) mm, flowrate (10−20) g/min and pressure (10−60) MPa on the yield was investigated. Composition, yield, antioxidant activity (AA) and total phenolic content (TPC) were compared with ultrasound assisted extraction (UAE), hydrodistillation (HD) and Soxhlet (SX). Extraction yields and major compounds obtained were: HD: 23.7 mg/g, thymol; SX: 244 mg/g, caryophyllene; 3′-hydroxyb-naphtoflavone; UAE: 227 mg/g, carvacrol, (z)-3-(3-ethoxy-4-hydroxy-phenyl)-2-phenylacrylic acid; SFE: 38.50 mg/g, thymol, carvacrol, (+-)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, 5-hydroxyflavone and icarrin. SX presented better AA (IC<sub>50-DPPH</sub> =19.60 mg/mL) followed by UAE (IC<sub>50- DPPH</sub> =48.13 mg/mL) and HD better TPC (184.07 mg GAE/g). Antifungal activity against <em>Colletotrichum musae</em>, <em>Mucor racemosus</em> and <em>Fusarium verticillioides</em> was assessed, minimal inhibitory concentration (MIC) was obtained. VC obtained had the most active antifungal activity against fungus (MIC: (400, 400, 825) mg/L).</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106492"},"PeriodicalIF":3.4,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889327","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 objective of this study was to valorize hot-pressed, desolventized toasted canola meal by tailoring subcritical water extraction (SCW) conditions to enhance protein recovery while optimizing their physicochemical properties. A 3 × 3 face-centered central composite design using response surface methodology was applied to understand the interaction between extraction temperature (200–250°C), time (20–30 min), and feed concentration (5–20 %) at 4.03 MPa pressure and their effects on protein recovery, degree of hydrolysis (DH), interfacial tension (IFT), and total phenolic content (TPC). The extracts displayed a maximum protein recovery of 68.9 wt% with a maximum DH of 14.1 %. The extracted protein significantly reduced the IFT to a minimum of 4.0 mN/m. The extracts showed a high value of TPC (24.6 mg/g) and excellent antioxidative properties. Overall, it demonstrates the potential of SCW to transform low-value canola meals into high-value protein hydrolysates with enhanced surface activity and antioxidative properties for food and industrial applications.
{"title":"Subcritical water extraction of hydrolyzed proteins from canola meal: Optimization of recovery and physicochemical properties","authors":"Karandeep Singh Sodhi , Jianping Wu , Ajay Dalai , Supratim Ghosh","doi":"10.1016/j.supflu.2024.106494","DOIUrl":"10.1016/j.supflu.2024.106494","url":null,"abstract":"<div><div>The objective of this study was to valorize hot-pressed, desolventized toasted canola meal by tailoring subcritical water extraction (SCW) conditions to enhance protein recovery while optimizing their physicochemical properties. A 3 × 3 face-centered central composite design using response surface methodology was applied to understand the interaction between extraction temperature (200–250°C), time (20–30 min), and feed concentration (5–20 %) at 4.03 MPa pressure and their effects on protein recovery, degree of hydrolysis (DH), interfacial tension (IFT), and total phenolic content (TPC). The extracts displayed a maximum protein recovery of 68.9 wt% with a maximum DH of 14.1 %. The extracted protein significantly reduced the IFT to a minimum of 4.0 mN/m. The extracts showed a high value of TPC (24.6 mg/g) and excellent antioxidative properties. Overall, it demonstrates the potential of SCW to transform low-value canola meals into high-value protein hydrolysates with enhanced surface activity and antioxidative properties for food and industrial applications.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106494"},"PeriodicalIF":3.4,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889266","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 : 2024-12-06DOI: 10.1016/j.supflu.2024.106490
Hua Tian , Cheng Chang , Ligeng Li , Xianyu Zeng , Jianfeng Wang , Minghuan Yin , Yongchuan Wang , Jian Gong , Xuanang Zhang , Gequn Shu
To achieve carbon peaking and carbon neutrality goals, the CO2 transcritical power cycle is regarded as a promising technology for waste heat recovery. Variations in the working conditions of the engine can lead to significant fluctuations in waste heat. Therefore, to enhance adaptability to changes in heat sources, this study focuses on natural gas engines and proposes a dual split flow system for the CO2 transcritical power cycle based on heat capacity matching. This system features two diversion designs that can actively adjust the mass flow rate of carbon dioxide through different heat sources, thereby actively adjusting the equivalent heat capacity of the working fluid and matching the changes in heat sources under varying operating conditions. Based on actual road conditions, this study establishes a dynamic model of system and proposes a flow adaptive allocation control strategy for achieving heat capacity matching. The study conducted simulations of the dynamic system of the waste heat recovery system under all engine operating conditions, and interesting results showed that CO2 transcritical power cycle achieved positive net power output under all engine operating conditions, with over 91 % of engine operating conditions achieving a cylinder liner water utilization rate greater than 99 %, under the studied engine operating conditions, the flue gas utilization rate was greater than 92.2 %, and the engine BTE increased by 2.96 −7.04 %.
{"title":"Dual split transcritical carbon dioxide cycle based on all engine operating conditions with high thermal adaptability","authors":"Hua Tian , Cheng Chang , Ligeng Li , Xianyu Zeng , Jianfeng Wang , Minghuan Yin , Yongchuan Wang , Jian Gong , Xuanang Zhang , Gequn Shu","doi":"10.1016/j.supflu.2024.106490","DOIUrl":"10.1016/j.supflu.2024.106490","url":null,"abstract":"<div><div>To achieve carbon peaking and carbon neutrality goals, the CO2 transcritical power cycle is regarded as a promising technology for waste heat recovery. Variations in the working conditions of the engine can lead to significant fluctuations in waste heat. Therefore, to enhance adaptability to changes in heat sources, this study focuses on natural gas engines and proposes a dual split flow system for the CO2 transcritical power cycle based on heat capacity matching. This system features two diversion designs that can actively adjust the mass flow rate of carbon dioxide through different heat sources, thereby actively adjusting the equivalent heat capacity of the working fluid and matching the changes in heat sources under varying operating conditions. Based on actual road conditions, this study establishes a dynamic model of system and proposes a flow adaptive allocation control strategy for achieving heat capacity matching. The study conducted simulations of the dynamic system of the waste heat recovery system under all engine operating conditions, and interesting results showed that CO2 transcritical power cycle achieved positive net power output under all engine operating conditions, with over 91 % of engine operating conditions achieving a cylinder liner water utilization rate greater than 99 %, under the studied engine operating conditions, the flue gas utilization rate was greater than 92.2 %, and the engine BTE increased by 2.96 −7.04 %.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106490"},"PeriodicalIF":3.4,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825385","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 : 2024-12-05DOI: 10.1016/j.supflu.2024.106489
Jacqueline Mansano Ortega , Vladimir Ferreira Cabral , Francisco Adrián Sánchez
Knowledge of phase equilibria and critical properties of CO2 + carboxylic acid systems is essential for supercritical fluid extraction (SCFE) processes, such as oil deacidification. However, modeling these systems is challenging due to their highly asymmetrical behavior. In this study, we apply the Group Contribution with Association Equation of State (GCA-EOS) to model vapor−liquid and liquid−liquid equilibria of the homologous series of CO2 + carboxylic acids. The GCA-EOS, previously validated for alkanes and alcohols, is extended to cover short and long-chain carboxylic acids. Using a single set of parameters, we validate the model against experimental data for C2−C20 acids, temperatures from 293 K to 473 K, and pressures up to 400 bar. The model successfully predicts phase equilibria across the entire homologous series, making it a reliable tool for assessing the multiphase behavior of these systems in SCFE applications.
了解二氧化碳+羧酸体系的相平衡和临界特性对于超临界流体萃取（SCFE）工艺（如石油脱酸）至关重要。然而，由于这些体系的行为极不对称，对其建模极具挑战性。在本研究中，我们应用了关联状态方程（GCA-EOS）来模拟 CO2 + 羧酸同源系列的汽液和液液平衡。GCA-EOS 先前已在烷烃和醇类中得到验证，现扩展到短链和长链羧酸。我们使用一组参数，根据 C2-C20 酸的实验数据、293 K 至 473 K 的温度和高达 400 bar 的压力对模型进行了验证。该模型成功预测了整个同源系列的相平衡，使其成为评估 SCFE 应用中这些体系多相行为的可靠工具。
{"title":"Multiphase equilibria modeling with GCA-EOS. Part III: CO2 with the homologous series of carboxylic acids","authors":"Jacqueline Mansano Ortega , Vladimir Ferreira Cabral , Francisco Adrián Sánchez","doi":"10.1016/j.supflu.2024.106489","DOIUrl":"10.1016/j.supflu.2024.106489","url":null,"abstract":"<div><div>Knowledge of phase equilibria and critical properties of CO<sub>2</sub> + carboxylic acid systems is essential for supercritical fluid extraction (SCFE) processes, such as oil deacidification. However, modeling these systems is challenging due to their highly asymmetrical behavior. In this study, we apply the Group Contribution with Association Equation of State (GCA-EOS) to model vapor−liquid and liquid−liquid equilibria of the homologous series of CO<sub>2</sub> + carboxylic acids. The GCA-EOS, previously validated for alkanes and alcohols, is extended to cover short and long-chain carboxylic acids. Using a single set of parameters, we validate the model against experimental data for C<sub>2</sub>−C<sub>20</sub> acids, temperatures from 293 K to 473 K, and pressures up to 400 bar. The model successfully predicts phase equilibria across the entire homologous series, making it a reliable tool for assessing the multiphase behavior of these systems in SCFE applications.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106489"},"PeriodicalIF":3.4,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825386","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 : 2024-12-03DOI: 10.1016/j.supflu.2024.106475
F.E. Benelli, G.O. Pisoni, M. Cismondi-Duarte
Enhanced oil recovery (EOR) involves several techniques, including the injection of gas (such as natural gas, nitrogen, or ) into the reservoir to increase its pressure, thereby displacing oil from one or more injection wells to production wells. For this process to be effective, it is essential that the injected gas and the oil reach a homogeneous state. Particularly, the First-Contact Minimum Miscibility Pressure (FC-MMP) offers a reliable (and safe) initial estimate for the pressure at which the EOR process should be conducted. In this work, an efficient algorithm is developed that allows computing complete pressure(P)- diagrams (: percentage of injected gas) at a fixed temperature using traditional cubic equations of state (EoS), including complex cases with three-phase regions. This algorithm is used to study both the qualitative and quantitative behaviour of the P- diagrams and to analyse how FC-MMP changes with the injection of different gases or gas mixtures. Various reservoir fluids from the literature (with and without asphaltenes and with varying levels of and methane) are evaluated. In one section, three injection gases are used: , , and a synthetic natural gas mixture, comparing their effects on the P- diagrams. Then, the impact of interaction parameters on phase equilibrium and FC-MMP is analysed, and the role of asphaltene precipitation is discussed. The study concludes with a quantitative comparison between the FC-MMP calculated here and the Multiple-Contact MMP (MC-MMP) reported for the same fluids. Additionally, the problem of whether asphaltenes precipitation should be considered or ignored in the determination of the FC-MMP is analysed and discussed, with different perspectives for conventional and non-conventional shale type reservoirs.
{"title":"Complex phase behaviours related to gas injection in reservoir fluids","authors":"F.E. Benelli, G.O. Pisoni, M. Cismondi-Duarte","doi":"10.1016/j.supflu.2024.106475","DOIUrl":"10.1016/j.supflu.2024.106475","url":null,"abstract":"<div><div>Enhanced oil recovery (EOR) involves several techniques, including the injection of gas (such as natural gas, nitrogen, or <span><math><msub><mrow><mi>CO</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>) into the reservoir to increase its pressure, thereby displacing oil from one or more injection wells to production wells. For this process to be effective, it is essential that the injected gas and the oil reach a homogeneous state. Particularly, the First-Contact Minimum Miscibility Pressure (FC-MMP) offers a reliable (and safe) initial estimate for the pressure at which the EOR process should be conducted. In this work, an efficient algorithm is developed that allows computing complete pressure(P)-<span><math><mi>α</mi></math></span> diagrams (<span><math><mi>α</mi></math></span>: percentage of injected gas) at a fixed temperature using traditional cubic equations of state (EoS), including complex cases with three-phase regions. This algorithm is used to study both the qualitative and quantitative behaviour of the P-<span><math><mi>α</mi></math></span> diagrams and to analyse how FC-MMP changes with the injection of different gases or gas mixtures. Various reservoir fluids from the literature (with and without asphaltenes and with varying levels of <span><math><msub><mrow><mi>CO</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> and methane) are evaluated. In one section, three injection gases are used: <span><math><msub><mrow><mi>CO</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>, <span><math><msub><mrow><mi>N</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>, and a synthetic natural gas mixture, comparing their effects on the P-<span><math><mi>α</mi></math></span> diagrams. Then, the impact of interaction parameters on phase equilibrium and FC-MMP is analysed, and the role of asphaltene precipitation is discussed. The study concludes with a quantitative comparison between the FC-MMP calculated here and the Multiple-Contact MMP (MC-MMP) reported for the same fluids. Additionally, the problem of whether asphaltenes precipitation should be considered or ignored in the determination of the FC-MMP is analysed and discussed, with different perspectives for conventional and non-conventional shale type reservoirs.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106475"},"PeriodicalIF":3.4,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789991","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 : 2024-11-30DOI: 10.1016/j.supflu.2024.106486
Rui Zhang, Shuaiqi Zhao, Han Huang, Kunpeng Zhao, Bofeng Bai
Supercritical water gasification (SCWG) technology enables the efficient utilisation of lignite to produce H2, CO, and CO2. Coal gasification differs under different atmospheres and H2 promotes the pyrolysis of carbon structures. While simultaneous increases in H2, CO, and CO2 are observed, their combined effect on the SCWG of coal remains unknown. Formic acid (FA) was used to produce H2, CO, and CO2 in the supercritical water, and the impact of the gaseous product generated from high-concentration (>30 wt%) FA decomposition on the SCWG of lignite was experimentally investigated. In comparison to lignite gasification in pure supercritical water, the carbon efficiency of lignite gasification in 30 wt% FA solution decreased by 7.66 %, and the mass conversion of lignite decreased by 4.0 %. Higher concentrations of CO and CO2 yielded stronger inhibition of lignite SCWG.
{"title":"High concentrations of CO and CO2 inhibit lignite gasification in supercritical water","authors":"Rui Zhang, Shuaiqi Zhao, Han Huang, Kunpeng Zhao, Bofeng Bai","doi":"10.1016/j.supflu.2024.106486","DOIUrl":"10.1016/j.supflu.2024.106486","url":null,"abstract":"<div><div>Supercritical water gasification (SCWG) technology enables the efficient utilisation of lignite to produce H<sub>2</sub>, CO, and CO<sub>2</sub>. Coal gasification differs under different atmospheres and H<sub>2</sub> promotes the pyrolysis of carbon structures. While simultaneous increases in H<sub>2</sub>, CO, and CO<sub>2</sub> are observed, their combined effect on the SCWG of coal remains unknown. Formic acid (FA) was used to produce H<sub>2</sub>, CO, and CO<sub>2</sub> in the supercritical water, and the impact of the gaseous product generated from high-concentration (>30 wt%) FA decomposition on the SCWG of lignite was experimentally investigated. In comparison to lignite gasification in pure supercritical water, the carbon efficiency of lignite gasification in 30 wt% FA solution decreased by 7.66 %, and the mass conversion of lignite decreased by 4.0 %. Higher concentrations of CO and CO<sub>2</sub> yielded stronger inhibition of lignite SCWG.</div></div>","PeriodicalId":17078,"journal":{"name":"Journal of Supercritical Fluids","volume":"218 ","pages":"Article 106486"},"PeriodicalIF":3.4,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789992","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}
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