CHEMICAL ENGINEERING JOURNAL
·
2022
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IF 16.744
Huang Liu,Huashi Li,Desong Yao,Ping Guo,Lianhui Wen
Due to the weak cementation of natural gas hydrate (NGH) reservoir in the seabed, during both the drilling and development processes, a multiphase (gas hydrate-sediments-seawater-natural gas mixture) flow is more likely to exist in the NGH reservoir and development wells, understand the natural gas hydrate particle dissociation kinetic in the hydrate-sediments/seawater slurries is important. In this work, first, a new NGH phase behavior research experimental apparatus contains a strong magnetic stirrer was built. By using this, we for the first time proposed to form NGH reservoir in the water saturated sands under stirring in the laboratory, which showed a much higher hydrate formation rate and water to hydrate conversation ratio than the usual static formation method. After that, the CH 4 hydrate-sands/seawater slurries were produced, the influence of pressures, temperatures, the size of sands, and stirring rates on CH 4 hydrate dissociation kinetic in the slurry were investigated. The dissociation rate of CH 4 hydrate-sands mixed particles markedly increased with decreasing operation pressure from 3 MPa to 0.1 MPa. The average dissociate rate reached 1762.57 mL/min at 0.1 MPa. It is interesting that unlike to the single NGH reservoir, no hydrate secondary formation and ice formation phenomenon arose in the hydrate-sands/seawater slurries during the CH 4 hydrate dissociation process. The increase of temperature and stirring rate substantially stimulated the dissociation of CH 4 hydrate particles in the slurry, while the sands’ size showed little effect. In addition, a high precision kinetic model for describing the dissociation of CH 4 hydrate in hydrate-sands/seawater slurries was built, in which the influence of pressure, temperature and stirring rate on the hydrate apparent dissociation rate constant was considered at the same time.
研究领域:
化学工程
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING RESEARCH & DESIGN
·
2019
·
IF 3.073
Wenkan Fang,Zhe Wang,Qiang Xie,Yan Liu,Deyi Wu
In developing a magnetic material for the recovery of phosphate from water/wastewater, both high magnetization and high uptake ability for phosphate are highly desirable. In our quest to obtain such a magnetic material, hydrous zirconia-coated magnetite nanocomposite (Fe 3 O 4 @ZrO 2 ) has been synthesized at different end-point pH values and stirring rates. The results indicated that the saturation magnetization of Fe 3 O 4 @ZrO 2 increased almost linearly with increasing end-point pH, and high stirring rate caused low magnetization. The magnetization behavior was closely related to the formation of the mineral magnetite, which was hindered at either low end-point pH or fast stirring rate. In contrast to magnetization, phosphate adsorption capacity decreased with increasing end-point pH, whereas the stirring rate had little effect. It is concluded that adopting a relatively low end-point pH and a low stirring rate is a good strategy for obtaining a Fe 3 O 4 @ZrO 2 material with good magnetic separability and a high affinity for P.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2023
·Vol. 129
·期 9
·1-14
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IF 2.7
Zheng Yayuan,Shen Yueqiu,Ma Yulan,Wang Jiao,Wu Xieping,Yang Meihui,Xu Menglin,Tian Yongqi
Crystallization kinetics serve as the foundation for understanding crystallization behavior and designing crystallizer scale-ups. This study investigates the crystallization kinetics of Potassium Chloride (KCl) during the cooling crystallization process, utilizing the intermittent dynamic method under varying experimental conditions within a continuous mixed-suspension mixed-product-removal (MSMPR) crystallizer. Concurrently, the study explores the functional relationship between particle size and crystal growth rate. Kinetic rates were determined using a least-squares method for multivariate linear regression, and the validity of the kinetic model was confirmed through experimental testing. The findings suggest that the KCl crystallization process is governed by surface reaction, and that coalescence occurs between particles. It was observed that an increase in suspension density, supersaturation ratio, and stirring rate enhances both the nucleation rate and growth rate of KCl. The factors influencing the nucleation rate of KCl crystals, in order of significance, are stirring rate, supersaturation, and suspension density. Additionally, an increase in stirring rate was found to inhibit aggregation. Further investigation revealed that the growth rate of KCl crystals is size-dependent. Consequently, growth rate equations for KCl during the cooling crystallization process were derived using two particle-size-dependent growth rate models. When compared to the CR model, the MJ2 model demonstrated superior relevance and adaptability to experimental results in describing the population density distribution of KCl, with an average relative error of approximately 13.37% between model values and experimental data. This research offers valuable theoretical guidance for optimizing the crystallization process and designing industrial crystallizers.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CRYSTAL RESEARCH AND TECHNOLOGY
·
2025
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IF 1.9
Xingchao Fan,Bangfu Huang,Zhe Shi,Linjing Yang,Fu Yuan,Keying Zhu,Daoping Zhan
Aiming at the problems of low crystallization rate and uneven particle size during evaporative crystallization of ammonium sulfate mother liquor (a by-product of ammonia desulfurization of sintered flue gas), this study investigated via orthogonal tests the effects of evaporation temperature, pH, stirring rate, and calcium sulfate addition on crystallization amount, average particle size, and coefficient of variation (C.V.). The results showed: For crystallization amount, the influence degree was evaporation temperature>pH>stirring rate>calcium sulfate addition; for average particle size, it was stirring rate>pH>evaporation temperature>calcium sulfate addition; for C.V. value, it was stirring rate>pH>calcium sulfate addition>evaporation temperature. Crystal morphologies included hexahedral, columnar, lamellar, etc., with aggregation under some conditions. Crystals contained calcium, nitrogen, oxygen, and sulfur elements(Ca, N, O, S); Ca content increased with calcium sulfate addition. Ammonium sulfate crystals' diffraction peaks matched pure ammonium sulfate, with the highest peaks at pH 5.0, 250 rpm stirring, 3500 mg·L −1 calcium sulfate, and 333.15K.
研究领域:
化学工程
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结晶学
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环境工程
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无机化学
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过程优化
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE
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2025
·
IF 3.6
Li Zhao,Shulai Lu,Ming Chen,Yuchao Wang,Lei Ning,Shicheng Zhao
The agglomeration of polybutadiene latex (PBL) is a complex process influenced by numerous factors. Up to now, the change of particle size of agglomerated PBL with time under varying conditions remains unclear, and the agglomeration kinetic model of PBL has not been proposed. In this study, the influence of the process parameters on the particle size of agglomerated PBL with time was studied, including the amount of agglomerating agent, temperature, stirring rate, and solid content of PBL. According to the particle size evolution of agglomerated PBL, the agglomeration process of PBL is divided into two stages, including the dispersion of the agglomerating agent and its adsorption and coalescence with PBL (stage I), followed by the shrinkage of agglomerated PBL particles (stage II). It was found that the process of stage I can be accelerated significantly by increasing the amount of agglomerating agent and agglomeration temperature during PBL agglomeration, thereby reducing the total agglomeration time. The mean particle size of agglomerated PBL was also reduced when the agglomeration process reached stability. With the increase of stirring rate, the time required for agglomeration of PBL and the mean particle size of agglomerated PBL decrease. The higher the solid content of pre-agglomerate PBL, the shorter the time for PBL to complete the agglomeration, but it has no obvious effect on the mean particle size of agglomerated PBL. Based on the experimental results, on the one hand, a novel method for expressing the particle size shrinkage of agglomerated PBL was developed. This analysis was based on the change of mean particle size of agglomerated PBL with time. On the other hand, the Boltzmann equation was used to fit the agglomeration kinetics of the whole process of PBL agglomeration. The results showed that the predicted values were in good agreement with the experimental values when PBL was agglomerated under different process parameters. Knowledge obtained from this study will provide insight into the influence of process parameters on the particle size of agglomerated PBL over time, and the establishment of kinetic models can help the industrial development of PBL agglomeration technology. Graphical
研究领域:
化学工程
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高分子科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 43
·24783-24790
·
IF 3.049
Yabin Wang,Keke Hu,Juan He,Yantu Zhang
Dendritic fibrous nano-silica (DFNS), also well-known as KCC-1, possesses three-dimensional center-radial nanochannels and hierarchical nanopores. Compared with conventional mesoporous materials like SBA-15, these special structural characteristics endow DFNS with more accessible internal space, higher specific surface area, larger pore volume, etc. Even though great progress has been achieved, the as-prepared KCC-1 nanospheres exhibit extremely non-uniform diameters and their sizes differ enormously in almost all available traditional synthesis approaches. Herein, a facile and low-cost one-pot rotating hydrothermal approach is adopted to improve the size uniformity of dendritic fibrous nano-silica. Stirring rates of 30, 60, 90, 120, and 150 (the maximum) revolutions per minute (rpm) can influence KCC-1 uniformity to certain extents. Among them, 60 rpm can be considered to be an ideal stirring rate for relatively uniform KCC-1 because of the best sufficient contact of reaction phases. A plausible synthesis mechanism can be explained in terms of continuously variable stress conditions of the reaction mother liquor (i.e., the bicontinuous microemulsion) during the fabrication process. To be specific, except for gravity (G), this technique brings about the centrifugal force (F) stemming from the stirring rate, and the buoyancy (f) originated from vigorous reversal of organic phase in the reaction solution. These forces synergistically mix organic phase and water phase, which generates new bicontinuous microemulsion droplets (BMDs) to supplement the consumed ones. All in all, this approach as well as the synthesis equipment is simple, inexpensive, and reproducible for large-scale KCC-1 preparation with improved size uniformity.
研究领域:
纳米材料学
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无机化学
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材料科学
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胶体与界面化学
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功能材料
✓ 已验证
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2023
·
IF 7.8
Hang Yao,Lei Ni,Yinshan Liu,Gang Fu,Juncheng Jiang,Zhen Cheng,Yuqing Ni,Zhiquan Chen
The exothermic pattern of m-xylene nitration with mixed acid in semi-batch mode was studied by reaction calorimetry . Adiabatic temperature rise ( Δ T ad ) and reaction enthalpy ( ∆ H ) were obtained to identify the thermal hazard. Process conditions including stirring rate, reaction temperature and strength of mixed acid were studied to optimize the reaction. Optimal yield (95.5%) was reached under the conditions of sufficient stirring rate, 70% strength of mixed acid and reaction temperature of 40 °C. Meanwhile, the thermal stability of nitration products was investigated by differential scanning calorimetry (DSC) and accelerating rate calorimetry (ARC). Pyrolysis kinetic parameters were calculated under non-isothermal and adiabatic conditions . Furthermore, the maximum temperature of the runaway system for synthesis reaction ( MTSR ) was determined to analyze the reaction hazard. The thermal risk of nitration of m-xylene was also assessed by the risk matrix and Stoessel criticality diagram. In addition, the nitration mechanism of m-xylene was presented. The active site for the electrophilic reaction of m-xylene was predicted via theoretical approach which was in consistent with the selectivity obtained by the experiment. These findings provide guidance for the safe operation of m-xylene nitration and can be used for further scale-up.
研究领域:
化工工程
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热安全
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过程优化
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反应动力学
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风险评估
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）