Pub Date : 2024-04-24DOI: 10.1016/j.partic.2024.04.005
Hang Li , Kaisheng Yao , Tianhang Liu , Weiwei Lu , Haili Zhao
Au hierarchical architectures with special morphology and structures are strongly desired in varied applications. Herein, a simple synthesis method was developed for the one-step preparation of Au micronails (MNs) at the planar liquid-liquid interface under mild conditions. The well-defined Au MNs were grown and constructed at CHCl3–H2O interface at room temperature using aniline in CHCl3 as reducing agent and HAuCl4 in H2O as precursor and no surfactant or seed is required. The intriguing Au MNs with rough surface consist of big heads and thin rods, just like iron nails in outline. Furthermore, through simple changing the reagent concentrations, the length and surface roughness of Au MNs can be adjusted conveniently. The effects of a series of factors on the morphology and structure of the products are studied in detail. With p-aminothiophenol as a molecular probe, the as-obtained Au MNs all exhibit dramatically improved surface enhanced Raman scattering sensitivity and high reproducibility, the enhancement factor and limit of detection of Au MNs are 5.4 × 105 and 1.0 × 10−10, respectively.
{"title":"Facile interfacial synthesis of gold micronails with adjustable length and roughness and their superior SERS properties for the detection of p-aminothiophenol","authors":"Hang Li , Kaisheng Yao , Tianhang Liu , Weiwei Lu , Haili Zhao","doi":"10.1016/j.partic.2024.04.005","DOIUrl":"10.1016/j.partic.2024.04.005","url":null,"abstract":"<div><p>Au hierarchical architectures with special morphology and structures are strongly desired in varied applications. Herein, a simple synthesis method was developed for the one-step preparation of Au micronails (MNs) at the planar liquid-liquid interface under mild conditions. The well-defined Au MNs were grown and constructed at CHCl<sub>3</sub>–H<sub>2</sub>O interface at room temperature using aniline in CHCl<sub>3</sub> as reducing agent and HAuCl<sub>4</sub> in H<sub>2</sub>O as precursor and no surfactant or seed is required. The intriguing Au MNs with rough surface consist of big heads and thin rods, just like iron nails in outline. Furthermore, through simple changing the reagent concentrations, the length and surface roughness of Au MNs can be adjusted conveniently. The effects of a series of factors on the morphology and structure of the products are studied in detail. With <em>p</em>-aminothiophenol as a molecular probe, the as-obtained Au MNs all exhibit dramatically improved surface enhanced Raman scattering sensitivity and high reproducibility, the enhancement factor and limit of detection of Au MNs are 5.4 × 10<sup>5</sup> and 1.0 × 10<sup>−10</sup>, respectively.</p></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140767949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-23DOI: 10.1016/j.partic.2024.04.004
Qingshan Jian , Hailin Gu , Kaige Wang , Shuai Wang , Mingxiu Zhan , Jinqing Wang , Longjie Ji , Zuohe Chi , Guangxue Zhang
Rotary kiln is widely used for thermal disposal of solid waste due to its effectiveness and high efficiency in recent years. To further improve the processing efficiency, a newly designed rotary kiln with three-section structure is proposed, and the behaviours of particle motion and heat transfer are investigated. Firstly, a lab-scale rotary kiln is manufactured, and experiments are carried out. Verified by experimental data, a CFD-DEM numerical model is developed to analyze the particle motion and heat transfer characteristics with the effects of inlet flue gas temperature, feeding rate and rotating speed. The results show that the outlet temperature increases linearly with the flue gas temperature, while it is negatively correlated with the feeding rate and rotating speed. In addition, the volumetric heat transfer coefficient in this complex rotary kiln is analyzed, the overall heat transfer coefficient is between 200 and 700 W/(m3 K).
{"title":"Numerical study of particle behaviours and heat transfer in a complex rotary kiln","authors":"Qingshan Jian , Hailin Gu , Kaige Wang , Shuai Wang , Mingxiu Zhan , Jinqing Wang , Longjie Ji , Zuohe Chi , Guangxue Zhang","doi":"10.1016/j.partic.2024.04.004","DOIUrl":"10.1016/j.partic.2024.04.004","url":null,"abstract":"<div><p>Rotary kiln is widely used for thermal disposal of solid waste due to its effectiveness and high efficiency in recent years. To further improve the processing efficiency, a newly designed rotary kiln with three-section structure is proposed, and the behaviours of particle motion and heat transfer are investigated. Firstly, a lab-scale rotary kiln is manufactured, and experiments are carried out. Verified by experimental data, a CFD-DEM numerical model is developed to analyze the particle motion and heat transfer characteristics with the effects of inlet flue gas temperature, feeding rate and rotating speed. The results show that the outlet temperature increases linearly with the flue gas temperature, while it is negatively correlated with the feeding rate and rotating speed. In addition, the volumetric heat transfer coefficient in this complex rotary kiln is analyzed, the overall heat transfer coefficient is between 200 and 700 W/(m<sup>3</sup> K).</p></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140763368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-19DOI: 10.1016/j.partic.2024.04.003
Jialing Zhou , Rui Zhang , Dong Liu
Aluminum is an attractive alternative fuel, but it burns very inefficiently due to the formation of a dense Al2O3 layer which prevents O2 from diffusion to the surface of Al particles. In previous experiments, the combustion of millimeter-sized Al (mAl) particles in the fluidized bed has achieved a substantial increase in the combustion efficiency, but further improvements are still needed. In this study, the effects of reaction atmosphere on the fluidized combustion of mAl particles were investigated. The experiments with different O2/H2O/CO2 concentrations were conducted. The experimental results indicate that the combustion efficiency of mAl particles in fluidized bed increases as the mole fraction of O2, H2O or CO2 increases, and the highest combustion efficiency can reach 38.7%. After the analysis of the oxide film on the surface of aluminum particles, it was found that it is easier to generate the unstable θ-Al2O3 under CO2 atmosphere, and it is easier to generate the unstable γ-Al2O3 and θ-Al2O3 under H2O atmosphere. The unstable Al2O3 film is more likely to be abraded in the fluidized bed, which leads to the effective improvement of the combustion efficiency.
铝是一种极具吸引力的替代燃料,但由于形成了致密的 Al2O3 层,阻止了氧气向铝颗粒表面的扩散,因此铝的燃烧效率非常低。在之前的实验中,在流化床中燃烧毫米大小的铝(mAl)颗粒已实现了燃烧效率的大幅提高,但仍需进一步改进。本研究调查了反应气氛对毫米级铝颗粒流化燃烧的影响。实验采用不同的 O2/H2O/CO2 浓度。实验结果表明,mAl 颗粒在流化床中的燃烧效率随着 O2、H2O 或 CO2 分子分数的增加而提高,最高燃烧效率可达 38.7%。经过对铝颗粒表面氧化膜的分析发现,在 CO2 气氛下更容易生成不稳定的θ-Al2O3,在 H2O 气氛下更容易生成不稳定的γ-Al2O3 和θ-Al2O3。不稳定的 Al2O3 薄膜更容易在流化床中被磨损,从而有效提高燃烧效率。
{"title":"Combustion characteristics of millimeter-sized aluminum particles in fluidized bed under various O2/CO2/H2O atmospheres","authors":"Jialing Zhou , Rui Zhang , Dong Liu","doi":"10.1016/j.partic.2024.04.003","DOIUrl":"https://doi.org/10.1016/j.partic.2024.04.003","url":null,"abstract":"<div><p>Aluminum is an attractive alternative fuel, but it burns very inefficiently due to the formation of a dense Al<sub>2</sub>O<sub>3</sub> layer which prevents O<sub>2</sub> from diffusion to the surface of Al particles. In previous experiments, the combustion of millimeter-sized Al (mAl) particles in the fluidized bed has achieved a substantial increase in the combustion efficiency, but further improvements are still needed. In this study, the effects of reaction atmosphere on the fluidized combustion of mAl particles were investigated. The experiments with different O<sub>2</sub>/H<sub>2</sub>O/CO<sub>2</sub> concentrations were conducted. The experimental results indicate that the combustion efficiency of mAl particles in fluidized bed increases as the mole fraction of O<sub>2</sub>, H<sub>2</sub>O or CO<sub>2</sub> increases, and the highest combustion efficiency can reach 38.7%. After the analysis of the oxide film on the surface of aluminum particles, it was found that it is easier to generate the unstable θ-Al<sub>2</sub>O<sub>3</sub> under CO<sub>2</sub> atmosphere, and it is easier to generate the unstable γ-Al<sub>2</sub>O<sub>3</sub> and θ-Al<sub>2</sub>O<sub>3</sub> under H<sub>2</sub>O atmosphere. The unstable Al<sub>2</sub>O<sub>3</sub> film is more likely to be abraded in the fluidized bed, which leads to the effective improvement of the combustion efficiency.</p></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140650781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-16DOI: 10.1016/j.partic.2024.04.001
Wuchang Zhou , Ruiqi Xie , Xiong Tong , Xian Xie , Yang Liu , Zhihui Zhao
A roasting-leaching test was carried out for the efficient utilization of clay-type lithium ore in the central region of Yunnan province. The test used the mixed acid of sulfuric acid and phosphoric acid as the leaching agent. Under the conditions of roasting temperature of 600 °C, roasting time of 1 h, liquid-solid ratio of 5:1, volume ratio of H2SO4 solution to H3PO4 solution of 45:5, leaching time of 2 h and leaching temperature of 80 °C, the leaching rate of lithium was as high as 97.83%. The leaching mechanism was studied by SEM, pore property analysis, XRD and XPS. It was found that the morphology of the ore changed obviously after roasting and leaching, and a certain degree of collapse and fragmentation occurred, which provided favorable spatial conditions for the leaching of lithium. The porosity, total intrusion volume and total pore area also increased after roasting and leaching, thus promoting the leaching of Li+. The results showed that chemical reaction taken placed during the roasting and leaching. The phase of the sample changed from chlorite, kaolinite and diaspore (boehmite) mainly to corundum, hematite, periclase and quartz after roasting. However, after leaching, no new phase was produced in the ore sample, and no S and P elements were found on the surface of the ore sample, indicating that the leaching mechanism of lithium might be the ion exchange between H+ and Li+.
{"title":"Extract lithium from clay-type lithium ore by mixed acid and its mechanism","authors":"Wuchang Zhou , Ruiqi Xie , Xiong Tong , Xian Xie , Yang Liu , Zhihui Zhao","doi":"10.1016/j.partic.2024.04.001","DOIUrl":"https://doi.org/10.1016/j.partic.2024.04.001","url":null,"abstract":"<div><p>A roasting-leaching test was carried out for the efficient utilization of clay-type lithium ore in the central region of Yunnan province. The test used the mixed acid of sulfuric acid and phosphoric acid as the leaching agent. Under the conditions of roasting temperature of 600 °C, roasting time of 1 h, liquid-solid ratio of 5:1, volume ratio of H<sub>2</sub>SO<sub>4</sub> solution to H<sub>3</sub>PO<sub>4</sub> solution of 45:5, leaching time of 2 h and leaching temperature of 80 °C, the leaching rate of lithium was as high as 97.83%. The leaching mechanism was studied by SEM, pore property analysis, XRD and XPS. It was found that the morphology of the ore changed obviously after roasting and leaching, and a certain degree of collapse and fragmentation occurred, which provided favorable spatial conditions for the leaching of lithium. The porosity, total intrusion volume and total pore area also increased after roasting and leaching, thus promoting the leaching of Li<sup>+</sup>. The results showed that chemical reaction taken placed during the roasting and leaching. The phase of the sample changed from chlorite, kaolinite and diaspore (boehmite) mainly to corundum, hematite, periclase and quartz after roasting. However, after leaching, no new phase was produced in the ore sample, and no S and P elements were found on the surface of the ore sample, indicating that the leaching mechanism of lithium might be the ion exchange between H<sup>+</sup> and Li<sup>+</sup>.</p></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140650782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Limestone or quicklime is a necessary flux in the iron ore sintering process. Its production and application process will cause CO2 emissions and various environmental pollution, but this has not attracted enough attention. Carbide slag (CS) is a calcium-rich solid waste produced in acetylene production, the harmless disposal of which is still incomplete, resulting in soil and groundwater pollution. This study investigated the granulation characteristics and sintering performance of the sintering mixture with different proportions of CS. The results show that replacing limestone with an appropriate proportion of CS is promising and beneficial to the formation of high-quality bonding phase. When CS accounts for 75% of the total mass of CS and limestone, the tumbler index increases by 8.10% and the comprehensive index decreases only from 100 to 96.16, which is within the acceptable range. The application of CS in iron ore sintering can achieve a clean disposal of it and a considerable carbon emission reduction, as the main component of which is Ca(OH)2.
{"title":"A clean disposal method of carbide slag with carbon emission reduction: Used as a flux for iron ore sintering","authors":"Hanxiao Meng, Jiankang Wang, Xiang Liu, Kelang Jin, Lei Zhang, Hao Zhou","doi":"10.1016/j.partic.2024.03.012","DOIUrl":"https://doi.org/10.1016/j.partic.2024.03.012","url":null,"abstract":"<div><p>Limestone or quicklime is a necessary flux in the iron ore sintering process. Its production and application process will cause CO<sub>2</sub> emissions and various environmental pollution, but this has not attracted enough attention. Carbide slag (CS) is a calcium-rich solid waste produced in acetylene production, the harmless disposal of which is still incomplete, resulting in soil and groundwater pollution. This study investigated the granulation characteristics and sintering performance of the sintering mixture with different proportions of CS. The results show that replacing limestone with an appropriate proportion of CS is promising and beneficial to the formation of high-quality bonding phase. When CS accounts for 75% of the total mass of CS and limestone, the tumbler index increases by 8.10% and the comprehensive index decreases only from 100 to 96.16, which is within the acceptable range. The application of CS in iron ore sintering can achieve a clean disposal of it and a considerable carbon emission reduction, as the main component of which is Ca(OH)<sub>2</sub>.</p></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140621926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-16DOI: 10.1016/j.partic.2024.04.002
Xiaoyu Li, Bowei Zhang, Huibo Wang, Hui Jin
The complex physical properties of supercritical water (SCW) make the heat transfer characteristics of particles within a particle cluster complicated. The heat transfer characteristics of single particle within a particle cluster in SCW, influenced by surrounding particles, have not been effectively explored. The numerical simulations were conducted to investigate the heat transfer characteristics of particle clusters in SCW under different conditions. The results were compared and analyzed with those from constant property flow. It was found that Reynolds number (Re) and the void fraction of particle cluster have no special effects on the variation trends of Nusselt number (Nu) for the focused particle. However, the particle temperature had a significant effect on the variation trends of Nu. The effect of Re on the heat transfer rate exponent (η) of the focused particle can be divided into two zones: a significant effect zone and a non-significant effect zone. The effect of void fraction on η in the non-significant effect zone was minimal. Within the non-significant effect zone, η decreased with the increasing particle temperature. In the significant effect zone, the variation trends of η became more complex. The fundamental reason for this series of phenomena is the changes in distribution of physical properties. A model for η was developed for the non-significant effect zone. This model can filter out the effects of Re and certain particle cluster spatial configurations, and it demonstrates good predictive performance.
{"title":"Effects of physical properties of supercritical water on heat transfer characteristics of single particle within a particle cluster","authors":"Xiaoyu Li, Bowei Zhang, Huibo Wang, Hui Jin","doi":"10.1016/j.partic.2024.04.002","DOIUrl":"10.1016/j.partic.2024.04.002","url":null,"abstract":"<div><p>The complex physical properties of supercritical water (SCW) make the heat transfer characteristics of particles within a particle cluster complicated. The heat transfer characteristics of single particle within a particle cluster in SCW, influenced by surrounding particles, have not been effectively explored. The numerical simulations were conducted to investigate the heat transfer characteristics of particle clusters in SCW under different conditions. The results were compared and analyzed with those from constant property flow. It was found that Reynolds number (<em>Re</em>) and the void fraction of particle cluster have no special effects on the variation trends of Nusselt number (<em>Nu</em>) for the focused particle. However, the particle temperature had a significant effect on the variation trends of <em>Nu</em>. The effect of <em>Re</em> on the heat transfer rate exponent (<em>η</em>) of the focused particle can be divided into two zones: a significant effect zone and a non-significant effect zone. The effect of void fraction on <em>η</em> in the non-significant effect zone was minimal. Within the non-significant effect zone, <em>η</em> decreased with the increasing particle temperature. In the significant effect zone, the variation trends of <em>η</em> became more complex. The fundamental reason for this series of phenomena is the changes in distribution of physical properties. A model for <em>η</em> was developed for the non-significant effect zone. This model can filter out the effects of <em>Re</em> and certain particle cluster spatial configurations, and it demonstrates good predictive performance.</p></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140613467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-12DOI: 10.1016/j.partic.2024.03.010
Linjing Yu, Min Su
The solid-liquid viscous system formed by high viscosity crystallization solution impacts the flow and separation performance. Therefore, it is very important to study the viscosity mechanism to improve viscosity and regulate crystallization, ensuring a seamless production process. Herein, the viscosity of crystallization solution was taken as the measurement parameter of caffeine as a model drug. We investigated the viscosity mechanism of caffeine crystallization solutions by combining experiment and simulation. The results indicated that the weak interactions between caffeine and water result in increased viscosity of the caffeine crystallization solutions. Moreover, caffeine crystals possess elongated needle-like shapes, featuring a substantial specific surface area. Additionally, there is π-π stacking occurring between the (2 0 0) crystal face and (1 1 0) crystal face, effectively fostering coalescence of the crystals towards the radial side of the crystal along its elongated axis, resulting in a more viscous crystallization system. The results contribute to comprehending the viscosity mechanism of crystal systems and provide theoretical foundation to enhance engineering efficiency in crystallization.
{"title":"Study on viscosity mechanism of caffeine crystallization solutions","authors":"Linjing Yu, Min Su","doi":"10.1016/j.partic.2024.03.010","DOIUrl":"10.1016/j.partic.2024.03.010","url":null,"abstract":"<div><p>The solid-liquid viscous system formed by high viscosity crystallization solution impacts the flow and separation performance. Therefore, it is very important to study the viscosity mechanism to improve viscosity and regulate crystallization, ensuring a seamless production process. Herein, the viscosity of crystallization solution was taken as the measurement parameter of caffeine as a model drug. We investigated the viscosity mechanism of caffeine crystallization solutions by combining experiment and simulation. The results indicated that the weak interactions between caffeine and water result in increased viscosity of the caffeine crystallization solutions. Moreover, caffeine crystals possess elongated needle-like shapes, featuring a substantial specific surface area. Additionally, there is π-π stacking occurring between the (2 0 0) crystal face and (1 1 0) crystal face, effectively fostering coalescence of the crystals towards the radial side of the crystal along its elongated axis, resulting in a more viscous crystallization system. The results contribute to comprehending the viscosity mechanism of crystal systems and provide theoretical foundation to enhance engineering efficiency in crystallization.</p></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140793658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The polymer on modulating the crystal's habit is an evolving research in pharmaceutical crystallization. This study demonstrates the crystal habit modification of chlorzoxazone (CHZ) by heterogeneous crystallization (HC) in the binary solvent acetonitrile-ethanol (A-E (1:1)) in the presence of polyvinylpyrrolidine (PVP) at concentrations of 0.50, 0.75, and 1.00 wt%. The A-E (1:1) and PVP in HC experiments influenced to change the shape of crystals from needle to plate shape and reduced the crystal size producing a lower aspect ratio (in the range of 1.5–2.3). In the presence of PVP, the CHZ size distribution is 65–78 μm which tends to enhance the powder flow-ability of CHZ crystals and as the PVP concentration increases, the nucleation rate decreases. The solubility of size-reduced CHZ crystals at different pH is found to be improved by 1.2–1.4 times. Hence, HC is deemed effective in modifying the physicochemical attributes of CHZ.
{"title":"Heterogeneous crystallization of Chlorzoxazone for modulating the physicochemical properties of crystals","authors":"Dhayananth Natarajan, Kalaichelvi Ponnusamy, Radhakrishnan Thota Karunakaran","doi":"10.1016/j.partic.2024.03.011","DOIUrl":"https://doi.org/10.1016/j.partic.2024.03.011","url":null,"abstract":"<div><p>The polymer on modulating the crystal's habit is an evolving research in pharmaceutical crystallization. This study demonstrates the crystal habit modification of chlorzoxazone (CHZ) by heterogeneous crystallization (HC) in the binary solvent acetonitrile-ethanol (A-E (1:1)) in the presence of polyvinylpyrrolidine (PVP) at concentrations of 0.50, 0.75, and 1.00 wt%. The A-E (1:1) and PVP in HC experiments influenced to change the shape of crystals from needle to plate shape and reduced the crystal size producing a lower aspect ratio (in the range of 1.5–2.3). In the presence of PVP, the CHZ size distribution is 65–78 μm which tends to enhance the powder flow-ability of CHZ crystals and as the PVP concentration increases, the nucleation rate decreases. The solubility of size-reduced CHZ crystals at different pH is found to be improved by 1.2–1.4 times. Hence, HC is deemed effective in modifying the physicochemical attributes of CHZ.</p></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140555147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In continuous biomass torrefaction plants, the products' yields, composition and homogeneity highly depend on the residence time of particles. A characterization of particle residence time distribution (RTD) was therefore carried out in an industrial-scale multiple hearth furnace on poplar wood chips using radio frequency identification tracers. The effects of operating conditions, namely, mass flow rate of biomass, shaft speed of the rabbling system and interdental length on the RTD were studied. The increase of shaft speed and mass flow rate reduces particles’ mean residence time. Lowering the length between two successive teeth also increases the bed speed. Uncontrollable biomass accumulation (also called “bulldozing”) was observed during several tests. This phenomenon is favored by a high mass flow rate of resources, a small interdental length between the teeth and a low shaft speed. RTD measurements were compared to the axial dispersion model. For all tests, the Peclet number is ranging between 20 and 62, indicating that the multiple hearth furnace cannot be modelled as an ideal plug flow reactor.
{"title":"Residence time distribution of wood chips in a semi-industrial multiple hearth furnace using RFID tracers","authors":"Elie Lacombe , Muriel Marchand , Capucine Dupont , Denis Maréchal , Thierry Melkior","doi":"10.1016/j.partic.2024.03.009","DOIUrl":"https://doi.org/10.1016/j.partic.2024.03.009","url":null,"abstract":"<div><p>In continuous biomass torrefaction plants, the products' yields, composition and homogeneity highly depend on the residence time of particles. A characterization of particle residence time distribution (RTD) was therefore carried out in an industrial-scale multiple hearth furnace on poplar wood chips using radio frequency identification tracers. The effects of operating conditions, namely, mass flow rate of biomass, shaft speed of the rabbling system and interdental length on the RTD were studied. The increase of shaft speed and mass flow rate reduces particles’ mean residence time. Lowering the length between two successive teeth also increases the bed speed. Uncontrollable biomass accumulation (also called “bulldozing”) was observed during several tests. This phenomenon is favored by a high mass flow rate of resources, a small interdental length between the teeth and a low shaft speed. RTD measurements were compared to the axial dispersion model. For all tests, the Peclet number is ranging between 20 and 62, indicating that the multiple hearth furnace cannot be modelled as an ideal plug flow reactor.</p></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674200124000518/pdfft?md5=0217bcdbb8c1f6d7a99171d8ccb88531&pid=1-s2.0-S1674200124000518-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140605335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-06DOI: 10.1016/j.partic.2024.03.007
Min Cai, Shuangzhu Kong, Mengxi Liu, Chunxi Lu
Oxidative coupling of methane (OCM) is characterized by high temperature and strong heat released. A riser reactor is designed for the OCM process to improve gas-solid contacting and heat transfer. This work illustrates the effect of hydrodynamic conditions and feed gas composition on the performance of an OCM riser reactor. The findings suggest that oxidative reactions predominantly occur within the acceleration zone and developed flow zone. Furthermore, at the low superficial gas velocity accompanied by a high solid circulating rate, the C2 yield initially increases in the acceleration zone, followed by a decrease in the developed flow zone and deceleration zone. The optimal operating conditions are a specific region corresponding to the solids holdup ranges from 0.015 to 0.02. Moreover, the C2 yield can be elevated using an appropriate feed mixture.
{"title":"Effect of operating conditions on the performance of riser reactor for oxidative coupling of methane","authors":"Min Cai, Shuangzhu Kong, Mengxi Liu, Chunxi Lu","doi":"10.1016/j.partic.2024.03.007","DOIUrl":"https://doi.org/10.1016/j.partic.2024.03.007","url":null,"abstract":"<div><p>Oxidative coupling of methane (OCM) is characterized by high temperature and strong heat released. A riser reactor is designed for the OCM process to improve gas-solid contacting and heat transfer. This work illustrates the effect of hydrodynamic conditions and feed gas composition on the performance of an OCM riser reactor. The findings suggest that oxidative reactions predominantly occur within the acceleration zone and developed flow zone. Furthermore, at the low superficial gas velocity accompanied by a high solid circulating rate, the C<sub>2</sub> yield initially increases in the acceleration zone, followed by a decrease in the developed flow zone and deceleration zone. The optimal operating conditions are a specific region corresponding to the solids holdup ranges from 0.015 to 0.02. Moreover, the C<sub>2</sub> yield can be elevated using an appropriate feed mixture.</p></div>","PeriodicalId":401,"journal":{"name":"Particuology","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140548008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}