Pub Date : 2024-08-03DOI: 10.1016/j.ces.2024.120579
Bubble deformation and breakup due to strain-rate-induced stress is investigated for a laminar flow configuration. The bubble shape is assumed to be a prolate ellipsoid. A new model for bubble deformation under dynamic load is introduced in the form of an ordinary differential equation for the deformation energy. Breakup is identified with a critical value of the deformation. As an application case, the flow in a joining T-junction is considered with the ratio of the volume flow rate being unity and the outflow Reynolds number being 1800. Dilute, dispersed bubbles with a diameter of 0.5 mm are injected. High-speed shadowgraphy is used and bubble parameters are evaluated via image processing. The capillary number is obtained from a single-phase flow simulation providing the instantaneous shear rate at the position of the bubble. The deformation resulting from the proposed model is then compared with the measured deformation for an exemplary bubble trajectory.
研究了层流构造中由于应变率引起的应力而导致的气泡变形和破裂。假定气泡的形状为椭圆形。以变形能量常微分方程的形式引入了动态载荷下气泡变形的新模型。破裂与变形的临界值有关。作为一个应用案例,考虑了连接 T 型交界处的流动,其体积流量比为 1,流出雷诺数为 1800。注入直径为 0.5 毫米的稀释分散气泡。使用高速阴影成像技术,通过图像处理评估气泡参数。毛细管数是通过提供气泡位置处瞬时剪切率的单相流模拟获得的。然后,将拟议模型产生的变形与测量到的典型气泡轨迹变形进行比较。
{"title":"Modeling of dynamic bubble deformation and breakup in T-junction channel flow","authors":"","doi":"10.1016/j.ces.2024.120579","DOIUrl":"10.1016/j.ces.2024.120579","url":null,"abstract":"<div><p>Bubble deformation and breakup due to strain-rate-induced stress is investigated for a laminar flow configuration. The bubble shape is assumed to be a prolate ellipsoid. A new model for bubble deformation under dynamic load is introduced in the form of an ordinary differential equation for the deformation energy. Breakup is identified with a critical value of the deformation. As an application case, the flow in a joining T-junction is considered with the ratio of the volume flow rate being unity and the outflow Reynolds number being 1800. Dilute, dispersed bubbles with a diameter of 0.5 mm are injected. High-speed shadowgraphy is used and bubble parameters are evaluated via image processing. The capillary number is obtained from a single-phase flow simulation providing the instantaneous shear rate at the position of the bubble. The deformation resulting from the proposed model is then compared with the measured deformation for an exemplary bubble trajectory.</p></div>","PeriodicalId":271,"journal":{"name":"Chemical Engineering Science","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0009250924008790/pdfft?md5=5709b826536fb0ca157e1dcdfe4b5a13&pid=1-s2.0-S0009250924008790-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-08-03DOI: 10.1016/j.ces.2024.120594
Demetalation-metalation method has gained prominence for its higher metal loading, efficiency and shortened synthetic period, particularly in the incorporation of metal atoms with large radii into zeolite framework in recent years. An ammonia-regulated approach has been developed for selectively evolved deep-substituted Ti precursors in dealuminized beta zeolites, which enables a controlled promotion of metalation of Ti atoms. Additionally, this ammonia-regulated approach could also enhance 1-hexene kinetic adsorption by constructing mesopores, which is demonstrated by the lower reaction order of 1-hexene. The synthesized ammonia-regulated N-Ti-beta exhibits rich framework Ti species and a high specific surface area, leading to significantly improved 1-hexene epoxidation performance (conversion of 61%, selectivity of 98%, and a high H2O2 utilization efficiency of 93%). This study not only provides a new strategy to dynamically regulate evolution of Ti precursors by ammonia but also holds promise for advancing related industrial processes in demetalation-metalation methods.
脱金属-金属化方法因其较高的金属负载量、效率和较短的合成周期而备受瞩目,特别是近年来在将大半径金属原子纳入沸石框架方面。目前已开发出一种氨调节方法,用于在脱铝 beta 沸石中选择性地进化深取代 Ti 前体,从而有控制地促进 Ti 原子的金属化。此外,这种氨调节方法还能通过构建介孔增强对 1-己烯的动力学吸附,1-己烯的较低反应阶数就证明了这一点。合成的氨调控 N-Ti-beta 具有丰富的框架 Ti 物种和较高的比表面积,从而显著提高了 1- 己烯的环氧化性能(转化率达 61%,选择性达 98%,H2O2 利用率高达 93%)。这项研究不仅为氨动态调节钛前驱体的演化提供了一种新策略,而且有望推动脱金属-金属化方法中相关工业流程的发展。
{"title":"Ammonia-regulated dynamic evolution of Ti precursor incorporating into dealuminized beta for efficient 1-Hexene epoxidation","authors":"","doi":"10.1016/j.ces.2024.120594","DOIUrl":"10.1016/j.ces.2024.120594","url":null,"abstract":"<div><p>Demetalation-metalation method has gained prominence for its higher metal loading, efficiency and shortened synthetic period, particularly in the incorporation of metal atoms with large radii into zeolite framework in recent years. An ammonia-regulated approach has been developed for selectively evolved deep-substituted Ti precursors in dealuminized beta zeolites, which enables a controlled promotion of metalation of Ti atoms. Additionally, this ammonia-regulated approach could also enhance 1-hexene kinetic adsorption by constructing mesopores, which is demonstrated by the lower reaction order of 1-hexene. The synthesized ammonia-regulated N-Ti-beta exhibits rich framework Ti species and a high specific surface area, leading to significantly improved 1-hexene epoxidation performance (conversion of 61%, selectivity of 98%, and a high H<sub>2</sub>O<sub>2</sub> utilization efficiency of 93%). This study not only provides a new strategy to dynamically regulate evolution of Ti precursors by ammonia but also holds promise for advancing related industrial processes in demetalation-metalation methods.</p></div>","PeriodicalId":271,"journal":{"name":"Chemical Engineering Science","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142048117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-08-02DOI: 10.1016/j.ces.2024.120587
The Euler-Euler/RANS approach is used to simulate the particle suspension in solid–liquid stirred vessels, with experimental validation conducted through the Electrical Sensing Zone Method (ESZ). An innovative evaluation method is introduced to quantify the critical impeller speed required for particles to achieve a specific uniform suspension state in dilute solutions. The impact of different vessel bottom shapes (flat, round, and W-shaped) on particle suspension characteristics is examined. The results indicate that optimizing the bottom shape to align with flow streamlines markedly enhances particle suspension, a conclusion supported by the Online Micro-sized Particle Analyzer (OMiPA). Further analysis shows baffle configurations transform tangential and axial velocities into radial velocity, which is not conducive to providing initial conditions for particle suspension. Overall, effective particle suspension relies on the interaction between main flow and turbulent fluctuations, with tangential and radial flows playing critical roles.
采用欧拉-欧拉/RANS 方法模拟固液搅拌容器中的颗粒悬浮,并通过电感区法(ESZ)进行实验验证。引入了一种创新的评估方法,用于量化颗粒在稀溶液中达到特定均匀悬浮状态所需的临界叶轮速度。研究了不同容器底部形状(扁形、圆形和 W 形)对颗粒悬浮特性的影响。结果表明,优化底部形状,使其与流动流线保持一致,可显著增强颗粒悬浮效果,在线微小颗粒分析仪(OMiPA)也支持这一结论。进一步的分析表明,挡板配置将切向速度和轴向速度转化为径向速度,不利于为颗粒悬浮提供初始条件。总之,有效的颗粒悬浮取决于主流和湍流波动之间的相互作用,其中切向流和径向流起着关键作用。
{"title":"Numerical simulation study of the influence of stirred vessel structure on particle suspension characteristics in dilute solutions","authors":"","doi":"10.1016/j.ces.2024.120587","DOIUrl":"10.1016/j.ces.2024.120587","url":null,"abstract":"<div><p>The Euler-Euler/RANS approach is used to simulate the particle suspension in solid–liquid stirred vessels, with experimental validation conducted through the Electrical Sensing Zone Method (ESZ). An innovative evaluation method is introduced to quantify the critical impeller speed <span><math><mrow><msub><mi>N</mi><mi>c</mi></msub></mrow></math></span> required for particles to achieve a specific uniform suspension state in dilute solutions. The impact of different vessel bottom shapes (flat, round, and W-shaped) on particle suspension characteristics is examined. The results indicate that optimizing the bottom shape to align with flow streamlines markedly enhances particle suspension, a conclusion supported by the Online Micro-sized Particle Analyzer (OMiPA). Further analysis shows baffle configurations transform tangential and axial velocities into radial velocity, which is not conducive to providing initial conditions for particle suspension. Overall, effective particle suspension relies on the interaction between main flow and turbulent fluctuations, with tangential and radial flows playing critical roles.</p></div>","PeriodicalId":271,"journal":{"name":"Chemical Engineering Science","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-08-02DOI: 10.1016/j.ces.2024.120586
The reduction behavior of iron ore is the fundamental process in ferrous metallurgy. Considering the gas–solid interface-structure relationship, heterogeneous transfer-reaction behavior, and multiple reaction kinetics, this work provides an effective analytical tool to investigate the fluidized reduction of iron ore. The conical fluidized bed is numerically examined to be capable of preventing de-fluidization induced by the sticking behavior, due to the steady circulation of flow pattern and full fluidization of coarse agglomerates. Compared with the hydrogen concentration, the gas velocity shows a stronger influence on the agglomerate reduction rate for the more efficient gas–solid contact. For the simulated transitions of Fe2O3 → Fe3O4 → Fe(1-x)O → Fe are assumed to overlap each other, there exist discrepancies between computed and theoretical reduction degrees. The experimental and numerical findings can be used to develop a methodology for optimizing the operational complexity and economic benefits of the fluidized reduction of iron ore.
铁矿石的还原行为是黑色冶金的基本过程。考虑到气固界面结构关系、异质传递-反应行为和多重反应动力学,本研究为研究铁矿石的流化还原提供了有效的分析工具。通过数值研究发现,锥形流化床由于流型稳定循环和粗大团聚体的充分流化,能够防止由粘滞行为引起的去流化。与氢浓度相比,气速对团聚体减少率的影响更大,因为气固接触更有效。对于假设相互重叠的 Fe2O3 → Fe3O4 → Fe(1-x)O → Fe 的模拟转变,计算值与理论还原度之间存在差异。实验和数值结果可用于制定优化铁矿石流态化还原操作复杂性和经济效益的方法。
{"title":"Experimental investigation and CFD study of direct reduction of iron ore in the conical fluidized bed","authors":"","doi":"10.1016/j.ces.2024.120586","DOIUrl":"10.1016/j.ces.2024.120586","url":null,"abstract":"<div><p>The reduction behavior of iron ore is the fundamental process in ferrous metallurgy. Considering the gas–solid interface-structure relationship, heterogeneous transfer-reaction behavior, and multiple reaction kinetics, this work provides an effective analytical tool to investigate the fluidized reduction of iron ore. The conical fluidized bed is numerically examined to be capable of preventing de-fluidization induced by the sticking behavior, due to the steady circulation of flow pattern and full fluidization of coarse agglomerates. Compared with the hydrogen concentration, the gas velocity shows a stronger influence on the agglomerate reduction rate for the more efficient gas–solid contact. For the simulated transitions of Fe<sub>2</sub>O<sub>3</sub> → Fe<sub>3</sub>O<sub>4</sub> → Fe<sub>(1-x)</sub>O → Fe are assumed to overlap each other, there exist discrepancies between computed and theoretical reduction degrees. The experimental and numerical findings can be used to develop a methodology for optimizing the operational complexity and economic benefits of the fluidized reduction of iron ore.</p></div>","PeriodicalId":271,"journal":{"name":"Chemical Engineering Science","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141954246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-08-02DOI: 10.1016/j.ces.2024.120588
Respirable coal mine dust (RCMD) inhalation is identified as the main cause of the resurgence of coal worker’s pneumoconiosis (CWP) since the mid-1990s. At present, the predominant dust control technology is the water spray system. However, in practice, the capture efficiency of RCMD by this technology is relatively low. To understand the capturing mechanism and develop improvement strategies, this research is focused on the surface chemistry study of RCMD and its impact on a water surface using a dynamic model. Proximate analysis, chemical, and mineral composition of a run-of-mine (ROM) coal sample from Appalachian region were analyzed using a proximate analyzer, Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and X-ray Diffraction (XRD), respectively. Contact angles were measured by capillary rise test using the Washburn equation. Based on the dynamic model, the effects of particle size, density, contact angle, and surface tension on the critical sinking were investigated. It was pointed out in this work that reducing surface tension, in turn, decreases contact angle, which has been neglected in the literature. Regime maps for different minerals were created and showed that organic matter has the highest critical velocity due to its low density and high contact angle. Reducing water surface tension to the critical solid surface tension of coal around 30 mN/m could maximize the attachment efficiency. Scaling laws, constructed by force balance, led to the criteria of critical sinking: , i.e., . A semi-empirical formula for critical velocity was obtained by fitting the simulation data, . Attachment efficiency was defined and formu
{"title":"Effect of physicochemical properties on critical sinking and attachment of respirable coal mine dust impacting on a water surface","authors":"","doi":"10.1016/j.ces.2024.120588","DOIUrl":"10.1016/j.ces.2024.120588","url":null,"abstract":"<div><p>Respirable coal mine dust (RCMD) inhalation is identified as the main cause of the resurgence of coal worker’s pneumoconiosis (CWP) since the mid-1990s. At present, the predominant dust control technology is the water spray system. However, in practice, the capture efficiency of RCMD by this technology is relatively low. To understand the capturing mechanism and develop improvement strategies, this research is focused on the surface chemistry study of RCMD and its impact on a water surface using a dynamic model. Proximate analysis, chemical, and mineral composition of a run-of-mine (ROM) coal sample from Appalachian region were analyzed using a proximate analyzer, Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and X-ray Diffraction (XRD), respectively. Contact angles were measured by capillary rise test using the Washburn equation. Based on the dynamic model, the effects of particle size, density, contact angle, and surface tension on the critical sinking were investigated. It was pointed out in this work that reducing surface tension, in turn, decreases contact angle, which has been neglected in the literature. Regime maps for different minerals were created and showed that organic matter has the highest critical velocity due to its low density and high contact angle. Reducing water surface tension to the critical solid surface tension of coal around 30 mN/m could maximize the attachment efficiency. Scaling laws, constructed by force balance, led to the criteria of critical sinking: <span><math><mrow><msub><mi>U</mi><mtext>cr</mtext></msub><mspace></mspace><mo>∼</mo><mspace></mspace><msqrt><mrow><mfrac><mrow><mn>6</mn><mrow><mfenced><mrow><mn>1</mn><mo>-</mo><mi>cos</mi><mi>θ</mi></mrow></mfenced></mrow></mrow><mrow><mfenced><mrow><mn>2</mn><mi>D</mi><mo>+</mo><mn>1</mn></mrow></mfenced></mrow></mfrac></mrow></msqrt><msqrt><mrow><mfrac><msub><mi>γ</mi><mi>lv</mi></msub><mrow><msub><mi>ρ</mi><mi>l</mi></msub><mi>R</mi></mrow></mfrac></mrow></msqrt></mrow></math></span>, i.e., <span><math><mrow><msub><mtext>We</mtext><mtext>cr</mtext></msub><mspace></mspace><mo>∼</mo><mspace></mspace><mfrac><mrow><mn>12</mn><mrow><mfenced><mrow><mn>1</mn><mo>-</mo><mi>cos</mi><mi>θ</mi></mrow></mfenced></mrow></mrow><mrow><mfenced><mrow><mn>2</mn><mi>D</mi><mo>+</mo><mn>1</mn></mrow></mfenced></mrow></mfrac></mrow></math></span>. A semi-empirical formula for critical velocity was obtained by fitting the simulation data, <span><math><mrow><msub><mi>U</mi><mrow><mi>cr</mi></mrow></msub><mo>=</mo><mn>1.09</mn><msqrt><mrow><mfrac><mrow><mn>6</mn><mrow><mfenced><mrow><mn>1</mn><mo>-</mo><mi>cos</mi><mi>θ</mi></mrow></mfenced></mrow></mrow><mrow><mfenced><mrow><mn>2</mn><mi>D</mi><mo>+</mo><mn>1</mn></mrow></mfenced></mrow></mfrac></mrow></msqrt><msqrt><mrow><mfrac><msub><mi>γ</mi><mrow><mi>lv</mi></mrow></msub><mrow><msub><mi>ρ</mi><mi>l</mi></msub><mi>R</mi></mrow></mfrac></mrow></msqrt></mrow></math></span>. Attachment efficiency was defined and formu","PeriodicalId":271,"journal":{"name":"Chemical Engineering Science","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141991101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-08-02DOI: 10.1016/j.ces.2024.120593
The new intensified strategy can be used in special distillation processes to achieve energy savings. Through analyzing the influence of different extractants and pressure on the separation performance of n-hexane-tetrahydrofuran-ethanol. system, extractive pressure-swing distillation process (EPSD) using dimethyl sulfoxide as extractant was proposed. Multi-objective optimization was performed to definite the best operating parameters of EPSD. Based on the phenomenon that the temperature of high-temperature column top is lower than low-temperature column bottom, making it impossible to perform traditional thermal integration, an intermediate heat exchange intensified process (IHE-EPSD) was developed. The performance influencing factors and heat exchange network of IHE-EPSD were analyzed to obtained the optimal IHE-EPSD process. Three heat integration schemes of the IHE-EPSD were designed to further save energy consumption. Finally, the processes were assessed from economy, energy, environment and exergy. The results indicate that the IHE-EPSD process exhibits excellent separation performance, achieving the efficient separation of n-hexane-tetrahydrofuran-ethanol.
{"title":"A novel intermediate heat exchange intensified extractive pressure-swing distillation process for efficiently separating n-hexane-tetrahydrofuran-ethanol","authors":"","doi":"10.1016/j.ces.2024.120593","DOIUrl":"10.1016/j.ces.2024.120593","url":null,"abstract":"<div><p>The new intensified strategy can be used in special distillation processes to achieve energy savings. Through analyzing the influence of different extractants and pressure on the separation performance of n-hexane-tetrahydrofuran-ethanol. system, extractive pressure-swing distillation process (EPSD) using dimethyl sulfoxide as extractant was proposed. Multi-objective optimization was performed to definite the best operating parameters of EPSD. Based on the phenomenon that the temperature of high-temperature column top is lower than low-temperature column bottom, making it impossible to perform traditional thermal integration, an intermediate heat exchange intensified process (IHE-EPSD) was developed. The performance influencing factors and heat exchange network of IHE-EPSD were analyzed to obtained the optimal IHE-EPSD process. Three heat integration schemes of the IHE-EPSD were designed to further save energy consumption. Finally, the processes were assessed from economy, energy, environment and exergy. The results indicate that the IHE-EPSD process exhibits excellent separation performance, achieving the efficient separation of n-hexane-tetrahydrofuran-ethanol.</p></div>","PeriodicalId":271,"journal":{"name":"Chemical Engineering Science","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-07-31DOI: 10.1016/j.ces.2024.120581
Bio-butanol as a renewable energy can be produced through biomass fermentation. Among these, the adsorption-based technique is the most energy-efficient. However, the adsorption of small amounts of butanol from the aqueous phase remains a challenge. In this work, poly (methyl methacrylate)-based (PMMA) cryogel particles with tunable polarity and a super-macroporous structure were prepared by combining a simple dropping method and sulfolane freeze casting. The maximum adsorption capacities of the PMMA cryogel particles using the batch shaking and fixed-bed were 520.2 and 1442.2 mg/g, respectively. Adsorption rate constant of amphiphilic cryogel particles increased by approximately 9–40 times compared with PMMA cryogel particles. Adsorption capacity of the PMMA-based cryogel particles was maintained at 99 % of the initial adsorption capacity after 10 cycles. This study presented a strategy for the design of adsorbents with super-macroporous structures and hydrophilic modification to facilitate the adsorption of hydrophobic butanol from the aqueous phase system.
{"title":"Amphiphilic super-macroporous cryogel particles for the high-efficiency separation of bio-butanol using a fixed-bed method","authors":"","doi":"10.1016/j.ces.2024.120581","DOIUrl":"10.1016/j.ces.2024.120581","url":null,"abstract":"<div><p>Bio-butanol as a renewable energy can be produced through biomass fermentation. Among these, the adsorption-based technique is the most energy-efficient. However, the adsorption of small amounts of butanol from the aqueous phase remains a challenge. In this work, poly (methyl methacrylate)-based (PMMA) cryogel particles with tunable polarity and a super-macroporous structure were prepared by combining a simple dropping method and sulfolane freeze casting. The maximum adsorption capacities of the PMMA cryogel particles using the batch shaking and fixed-bed were 520.2 and 1442.2 mg/g, respectively. Adsorption rate constant of amphiphilic cryogel particles increased by approximately 9–40 times compared with PMMA cryogel particles. Adsorption capacity of the PMMA-based cryogel particles was maintained at 99 % of the initial adsorption capacity after 10 cycles. This study presented a strategy for the design of adsorbents with super-macroporous structures and hydrophilic modification to facilitate the adsorption of hydrophobic butanol from the aqueous phase system.</p></div>","PeriodicalId":271,"journal":{"name":"Chemical Engineering Science","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-07-31DOI: 10.1016/j.ces.2024.120583
It delved into the pyrolysis-gasification behavior of waste pharmaceutical blisters (WPBs), exploring both kinetics and thermodynamics, and employing machine learning modeling. The decomposition of WPBs occurred in three stages, with temperature intervals of 140–350, 350–500, and 500–900 °C, respectively. Cyclization/aromatization reactions were hindered, as indicated by mass spectrometric analysis, which revealed the main evolved products, including CxHy, CH3OH, CH4, and H2. Apparent activation energy values obtained from FWO, KAS, Friedman, Cai & Chen models were comparable, showing a decreasing trend ranging from 264.9 to 48.4 kJ mol−1 at α ≤ 0.70, followed by a subsequent increase to 283.1 kJ mol−1 at a conversion of 0.80. The D1 model was more reliable in describing the pyrolysis-gasification process of WPBs. Machine learning modeling results indicated that the ANN19 with a topology structure of 5 ∗ 15 ∗ 1 and genetic programming models showed superior performance in predicting TG data.
{"title":"Pyrolysis-gasification conversion of waste pharmaceutical blisters: Thermo-kinetic and thermodynamic study, fuel gas analysis and machine learning modeling","authors":"","doi":"10.1016/j.ces.2024.120583","DOIUrl":"10.1016/j.ces.2024.120583","url":null,"abstract":"<div><p>It delved into the pyrolysis-gasification behavior of waste pharmaceutical blisters (WPBs), exploring both kinetics and thermodynamics, and employing machine learning modeling. The decomposition of WPBs occurred in three stages, with temperature intervals of 140–350, 350–500, and 500–900 °C, respectively. Cyclization/aromatization reactions were hindered, as indicated by mass spectrometric analysis, which revealed the main evolved products, including C<sub>x</sub>H<sub>y</sub>, CH<sub>3</sub>OH, CH<sub>4</sub>, and H<sub>2</sub>. Apparent activation energy values obtained from FWO, KAS, Friedman, Cai & Chen models were comparable, showing a decreasing trend ranging from 264.9 to 48.4 kJ mol<sup>−1</sup> at α ≤ 0.70, followed by a subsequent increase to 283.1 kJ mol<sup>−1</sup> at a conversion of 0.80. The D1 model was more reliable in describing the pyrolysis-gasification process of WPBs. Machine learning modeling results indicated that the ANN19 with a topology structure of 5 ∗ 15 ∗ 1 and genetic programming models showed superior performance in predicting TG data.</p></div>","PeriodicalId":271,"journal":{"name":"Chemical Engineering Science","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-07-31DOI: 10.1016/j.ces.2024.120582
Introducing cooling airflow is an effective method for achieving the localized cooling rate required during waste heat recovery of blast furnace slag. However, the associated parasitic loads must be considered. This study investigates moving bed heat exchanger with airflow-assisted cooling from an exergy perspective. The effects of the granular side Peclet number, airflow side Reynolds number, and the height ratio of the airflow section on heat loss, exergy destruction, and its distributions were examined experimentally. The results show that the trends of temperature and pressure exergy destruction with each parameter tend to be opposite. Therefore, optimizing the parameters requires a trade-off between different types of destruction. Additionally, reducing exergy destruction while meeting the cooling rate requirement was considered. The optimal parameter set was determined by taking the cooling rate requirement as a constraint and minimizing the dimensionless temperature and pressure exergy destruction to obtain the Pareto front.
{"title":"Optimization of exergy destruction minimization in moving bed heat exchanger with airflow-assisted cooling","authors":"","doi":"10.1016/j.ces.2024.120582","DOIUrl":"10.1016/j.ces.2024.120582","url":null,"abstract":"<div><p>Introducing cooling airflow is an effective method for achieving the localized cooling rate required during waste heat recovery of blast furnace slag. However, the associated parasitic loads must be considered. This study investigates moving bed heat exchanger with airflow-assisted cooling from an exergy perspective. The effects of the granular side Peclet number, airflow side Reynolds number, and the height ratio of the airflow section on heat loss, exergy destruction, and its distributions were examined experimentally. The results show that the trends of temperature and pressure exergy destruction with each parameter tend to be opposite. Therefore, optimizing the parameters requires a trade-off between different types of destruction. Additionally, reducing exergy destruction while meeting the cooling rate requirement was considered. The optimal parameter set was determined by taking the cooling rate requirement as a constraint and minimizing the dimensionless temperature and pressure exergy destruction to obtain the Pareto front.</p></div>","PeriodicalId":271,"journal":{"name":"Chemical Engineering Science","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-07-31DOI: 10.1016/j.ces.2024.120584
Packaging waste such as beverage carton forms a significant part of municipal solid waste and its pyrolysis behavior, kinetics, and thermodynamics were studied. A four-stage decomposition process was revealed: dehydration below 200 ℃, paperboard degradation at 200–400 ℃, polyethylene devolatilization at 400–550 ℃, and inorganic decomposition at 550–900 ℃. The evolved products included furans and acetic acid during stage II, followed by the presence of 2-butene and 1-pentene in the subsequent stage. Apparent activation energy (Ea) were determined using model-free models, revealing a notable level of comparability among these results. The average Ea was 123.6 kJ/mol within α range of 0.10–0.60, increasing to 233.3 kJ/mol beyond that range. The most probable reaction mechanism was determined, with the one-dimensional model proving more reliable. An artificial neural network model was developed to predict the thermal degradation. The selected topology of 5*15*1 displayed a robust ability to predict the thermal data.
{"title":"Pyrolysis conversion of multi-layer packaging waste under a CO2 atmosphere: Thermo-kinetic study, evolved products analysis and artificial neural networks modeling","authors":"","doi":"10.1016/j.ces.2024.120584","DOIUrl":"10.1016/j.ces.2024.120584","url":null,"abstract":"<div><p>Packaging waste such as beverage carton forms a significant part of municipal solid waste and its pyrolysis behavior, kinetics, and thermodynamics were studied. A four-stage decomposition process was revealed: dehydration below 200 ℃, paperboard degradation at 200–400 ℃, polyethylene devolatilization at 400–550 ℃, and inorganic decomposition at 550–900 ℃. The evolved products included furans and acetic acid during stage II, followed by the presence of 2-butene and 1-pentene in the subsequent stage. Apparent activation energy (Ea) were determined using model-free models, revealing a notable level of comparability among these results. The average Ea was 123.6 kJ/mol within α range of 0.10–0.60, increasing to 233.3 kJ/mol beyond that range. The most probable reaction mechanism was determined, with the one-dimensional model proving more reliable. An artificial neural network model was developed to predict the thermal degradation. The selected topology of 5*15*1 displayed a robust ability to predict the thermal data.</p></div>","PeriodicalId":271,"journal":{"name":"Chemical Engineering Science","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}