Chemical Engineering and Processing - Process Intensification最新文献_第3页

Process intensification in the direct contact membrane distillation (DCMD) desalination by patterning membrane surface: A CFD study 通过膜表面图案化强化直接接触膜蒸馏（DCMD）脱盐过程：CFD 研究

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-10-13 DOI: 10.1016/j.cep.2024.110027

In this research, the impact of pattern geometry on the intensification of the performance of surface patterned membranes for saline water desalination by direct contact membrane distillation (DCMD) is investigated by computational fluid dynamics (CFD) simulation. The Comsol Multiphysics software was applied to solve the governing transport equations for heat, momentum, and mass transfer. The result of the model was validated by the published experimental data, and the maximum deviation was <10 %. The target was to maximize the permeate flux by altering surface pattern geometry and dimensions. Based on the previous studies, a prism pattern was chosen in this work, and the influences of pattern type (3 types), pattern dimension (25–150 µm valley depth), and the distance between the valleys (0–400 µm) were studied on the temperature polarization coefficient (TPC) and DCMD permeate flux. The results showed that the pattern with a valley depth of 25 µm and a distance between the valleys of 300 µm had the best performance in DCMD operation. In this situation and feed temperature of 80 °C, a TPC of 0.78 and a water flux of 49.3 kg m^-12.h were attained. The characteristics of flow close to the patterned membrane surface were also investigated, and it was observed that there are weak shear stresses in the lower zone of the valleys, while stronger shear stresses are created in the upper regions that are responsible for improving the TPC and water flux in the patterned membranes.

本研究通过计算流体动力学（CFD）模拟，研究了图案几何形状对直接接触膜蒸馏法（DCMD）盐水脱盐表面图案膜性能强化的影响。应用 Comsol Multiphysics 软件求解了热量、动量和质量传递的支配传输方程。模型结果通过已公布的实验数据进行了验证，最大偏差为 10%。目标是通过改变表面图案的几何形状和尺寸使渗透流量最大化。根据之前的研究，本研究选择了棱柱图案，并研究了图案类型（3 种）、图案尺寸（25-150 µm 谷深）和谷间距（0-400 µm）对温度极化系数（TPC）和 DCMD 渗透通量的影响。结果表明，谷深为 25 µm、谷间距为 300 µm 的图案在 DCMD 运行中性能最佳。在这种情况下，进料温度为 80 °C，TPC 为 0.78，水流量为 49.3 kg m-12.h。此外，还对图案膜表面附近的流动特征进行了研究，结果表明，在沟谷的下部区域存在较弱的剪应力，而在上部区域则产生了较强的剪应力，这些剪应力是提高图案膜 TPC 和水通量的原因。

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引用次数: 0

Performance of a RuCs/MgO catalyst coated on additive manufactured support structures via electrophoretic deposition for ammonia synthesis 通过电泳沉积在添加剂制造的支撑结构上涂覆 RuCs/MgO 催化剂用于合成氨的性能

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-10-11 DOI: 10.1016/j.cep.2024.110019

This work investigates the electrophoretic deposition of a catalytic coating on so-called fluid guiding elements (FGE) with a ruthenium-based catalyst for use in ammonia synthesis reactors. FGE are additive manufactured metallic pipe inserts that have shown to enhance the heat transfer compared to empty pipes by dividing the fluid flow and alternately guiding the partial flows to the wall. Consequently, they could improve the performance of temperature sensitive structured catalytic systems. To be able to demonstrate the degree of process intensification, the required steps to enable the deposition of a reference catalyst for ammonia synthesis are developed. Further, the distribution of catalytically active compounds is characterized. The catalytic activity is assessed in a plug flow reactor under pressures up to 5 MPa and compared against a fixed bed from the same batch. The expected activity from the reference catalyst is calculated by a kinetic rate expression. The coating process does not affect catalytic activity, but a steady deactivation and high sensitivity to feed gas impurities are observed. Possible mechanisms for the deactivation are examined and discussed.

这项研究探讨了在所谓的流体导向元件（FGE）上电泳沉积催化涂层，并在氨合成反应器中使用钌基催化剂。FGE 是一种添加剂制造的金属管道插入件，与空管道相比，它通过分割流体流并交替引导部分流向管壁来提高传热效果。因此，它们可以提高对温度敏感的结构催化系统的性能。为了证明工艺强化的程度，我们开发了氨合成参考催化剂沉积所需的步骤。此外，还对催化活性化合物的分布进行了描述。在压力高达 5 兆帕的塞流反应器中对催化活性进行了评估，并与同批次的固定床进行了比较。参考催化剂的预期活性是通过动力学速率表达式计算得出的。涂层工艺不会影响催化活性，但会出现稳定的失活现象，而且对原料气体杂质的敏感性很高。对失活的可能机制进行了研究和讨论。

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引用次数: 0

Elucidating flow-directed 98% CO2 absorption using millimeter-sized coiled flow inverters: Nanocellulose-aided sustainable scope 利用毫米级卷流逆变器阐明流动定向吸收 98% 的二氧化碳：纳米纤维素辅助的可持续范围

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-10-10 DOI: 10.1016/j.cep.2024.110022

The Sustainable Development Goals (SDGs) adopted by the United Nations drive the global efforts to discover a sustainable carbon capture method for the reduction of anthropogenic CO₂ emissions. Concentrated alkanolamine solutions are being used as CO₂ capture mediums for batch processes amid several disadvantages, such as energy intensiveness and poor efficiency. In this work, millimeter-sized coiled flow inverters (CFI) have been explored as a point-source CO₂ capture tool for highly efficient, continuous operations. Solvent and CO₂ gas flow rates are found to dictate the slug flow regime and, more specfically, slug lengths. High interfacial area and residence time remain the driving factors for enhanced CO₂ capture using CFI. About 98% CO₂ absorption efficiency has been achieved for 3% aqueous diethanolamine solution in CFI . The efficacy of nanocellulose, a sustainable nanomaterial has been unearthed for CO₂ capture at low flow rate.

联合国通过的可持续发展目标（SDGs）推动全球努力探索一种可持续的碳捕集方法，以减少人为二氧化碳排放。浓缩的烷醇胺溶液作为二氧化碳捕集介质被用于批处理过程，但存在一些缺点，如能耗高、效率低。在这项工作中，我们探索了毫米级盘流逆变器（CFI），将其作为点源二氧化碳捕集工具，用于高效、连续的操作。研究发现，溶剂和二氧化碳气体流速决定了蛞蝓的流动机制，更具体地说，决定了蛞蝓的长度。高界面面积和停留时间仍然是利用 CFI 增强二氧化碳捕获的驱动因素。3% 的二乙醇胺水溶液在 CFI 中的二氧化碳吸收效率约为 98%。纳米纤维素是一种可持续发展的纳米材料，它在低流量二氧化碳捕集方面的功效已得到证实。

引用次数: 0

Hydrogenation process intensification of 2-nitro-4-acetylamino anisole by HiGee technology 利用 HiGee 技术强化 2-硝基-4-乙酰氨基苯甲醚的氢化过程

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-10-09 DOI: 10.1016/j.cep.2024.110020

The catalytic hydrogenation of 2-nitro-4-acetylamino anisole (NMA) is the main path to synthesize 2-amino-4-acetylamino anisole (AMA), belonging to a typical gas-liquid-solid system. However, the small mass transfer rate of traditional hydrogenation reactor can't match its intrinsic fast reaction rate, resulting in the low hydrogenation efficiency. In this work, a rotating packed bed (RPB) reactor with excellent mass transfer performance was applied for the hydrogenation process intensification of NMA. The characterization analysis of the commercial Raney-Ni catalyst shows that the liquid-solid mass transfer resistance during the reaction process can be ignored, and improving the gas-liquid mass transfer rate is the key to improve the macroscopic reaction rate. The effects of operating conditions (solvent, rotational speed, hydrogen pressure, temperature, and catalyst dosage) on NMA conversion and AMA selectivity were investigated. A macro-kinetic equation of NMA catalytic hydrogenation in the RPB reactor was proposed. Under optimized conditions, the NMA was completely converted in the RPB reactor within 30 min, while it took 4 h in the stirred tank reactor. The overall reaction efficiency of RPB reactor was increased by 87.5 % in comparison with STR. This study provides practical guidance for the industrial application of RPB reactor for gas-liquid-solid hydrogenation.

2-硝基-4-乙酰氨基苯甲醚（NMA）的催化加氢反应是合成2-氨基-4-乙酰氨基苯甲醚（AMA）的主要途径，属于典型的气-液-固体系。然而，传统加氢反应器的传质速率较小，无法与其固有的快速反应速率相匹配，导致加氢效率较低。本研究将传质性能优异的旋转填料床（RPB）反应器应用于 NMA 的氢化过程强化。对商用 Raney-Ni 催化剂的表征分析表明，反应过程中的液固传质阻力可以忽略不计，提高气液传质速率是提高宏观反应速率的关键。研究了操作条件（溶剂、转速、氢气压力、温度和催化剂用量）对 NMA 转化率和 AMA 选择性的影响。提出了 RPB 反应器中 NMA 催化加氢的宏观动力学方程。在优化条件下，NMA 在 RPB 反应器中可在 30 分钟内完全转化，而在搅拌罐反应器中则需要 4 小时。与 STR 反应器相比，RPB 反应器的整体反应效率提高了 87.5%。这项研究为工业应用 RPB 反应器进行气-液-固加氢反应提供了实际指导。

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引用次数: 0

Jet cavitation-enhanced hydration method for the preparation of magnesium hydroxide 制备氢氧化镁的喷射空化增强水合法

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-10-09 DOI: 10.1016/j.cep.2024.110003

During the preparation of magnesium hydroxide via the hydration method, in-situ growth and agglomeration often inhibit the reaction. This study used active magnesium oxide as the raw material and employed jet cavitation technology to enhance the hydration process. Based on the growth process of magnesium hydroxide, the mechanism of jet-enhanced hydration was analyzed. The effects of reaction temperature (T), reaction time (t), solid-liquid ratio (s), and cavitation number (σ) on the hydration rate were investigated. An L₂₅(5⁴) orthogonal experiment explored the significance of each factor's impact on the hydration rate. The hydration products were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and a specific surface area analyzer. Results indicate that the factors affecting the hydration rate, in order of significance, are cavitation number > reaction temperature > solid-liquid ratio > reaction time. The optimal process parameters were determined to be a reaction temperature of 70 °C, reaction time of 80 min, solid-liquid ratio of 1:12, and cavitation number of 0.42. Under these conditions, the hydration rate reached 94.87 %, producing well-dispersed lamellar magnesium hydroxide with a narrow particle size distribution (median particle size D50 = 4.511 μm) and a BET specific surface area of 11.345 m²/g.

在通过水合法制备氢氧化镁的过程中，原位生长和结块往往会抑制反应的进行。本研究以活性氧化镁为原料，采用射流空化技术强化水合过程。根据氢氧化镁的生长过程，分析了射流增强水合的机理。研究了反应温度（T）、反应时间（t）、固液比（s）和空化数（σ）对水合速率的影响。通过 L25(54) 正交实验探讨了各因素对水合速率影响的重要性。使用扫描电子显微镜 (SEM)、X 射线衍射 (XRD) 和比表面积分析仪对水合产物进行了表征。结果表明，影响水合速率的因素依次为空化数、反应温度、固液比和反应时间。最佳工艺参数确定为：反应温度 70 °C，反应时间 80 分钟，固液比 1:12，空化数 0.42。在这些条件下，水化率达到 94.87%，生成的片状氢氧化镁分散良好，粒度分布窄（中值粒度 D50 = 4.511 μm），BET 比表面积为 11.345 m²/g。

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引用次数: 0

Bubble characteristics in a novel microbubble gas-liquid-solid fluidized bed 新型微气泡气-液-固流化床中的气泡特性

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-10-06 DOI: 10.1016/j.cep.2024.110018

The bubble characteristics are critical in gas-liquid-solid fluidized beds and microbubbles significantly enhance mass transfer in multiphase systems. In this work, a novel concept of microbubble gas-liquid-solid fluidized bed is proposed. Telecentric camera is employed to measure and analyze the microbubble characteristics including bubble size and gas holdup in this three-phase fluidized bed. Additionally, solid holdups in the fluidized bed are also examined. The results demonstrate that the bubble size adheres a lognormal distribution and is significantly influenced by superficial gas velocity. Bubble diameter exhibit a relatively uniform distribution in the radial direction. Bubbles exceeding than 1 mm substantially affect local gas holdup, and the microbubble flow promotes a more uniform distribution of local gas holdup in radial position. The average gas holdup deviation is less than 15 % compared to overall gas holdup obtained from pressure drop. Although microbubbles are more abundant, larger bubbles (> 1 mm) contribute more to solid particle fluidization. This paper introduces a methodology for assessing smaller-sized microbubbles in three-phase flow. The hydrodynamic analysis of the microbubble gas-liquid-solid fluidized bed establishes a foundational framework for enhancing gas-liquid mass transfer in fluidized bed.

气泡特性在气-液-固流化床中至关重要，微气泡可显著提高多相系统中的传质效果。本研究提出了微气泡气-液-固流化床的新概念。采用远心相机测量和分析三相流化床中的微气泡特性，包括气泡大小和气体截留。此外，还考察了流化床中的固体滞留情况。结果表明，气泡大小呈对数正态分布，受表面气体速度的影响很大。气泡直径在径向分布相对均匀。超过 1 毫米的气泡会严重影响局部气体容积，而微气泡流则会促进局部气体容积在径向位置上的更均匀分布。与通过压降获得的整体气体容积相比，平均气体容积偏差小于 15%。虽然微气泡更多，但较大气泡（1 毫米）对固体颗粒流化的贡献更大。本文介绍了一种评估三相流中较小尺寸微气泡的方法。微气泡气-液-固流化床的流体力学分析为增强流化床中的气液传质建立了一个基础框架。

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引用次数: 0

Decentralized control of ideal ternary reactive distillation column with inert 带惰性的理想三元反应蒸馏塔的分散控制

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-10-02 DOI: 10.1016/j.cep.2024.110017

Decentralized control of an ideal hypothetical ternary reactive distillation column with an inert component is explored. Both composition measurement based and temperature inferential control structures are designed using simple heuristic approaches (two and three-point). The three-point composition control structure is proposed for the example RD column for the first time in this work. Although stable closed loop responses are seen for the throughput changes for all, the two-point structures have failed to achieve tight control of the product purity in the bottoms or purity of inert in the distillate for the inert composition changes due to fixed reflux ratio. The performances of the three-point control structures for the inert composition changes are quite satisfactory due to the indirect manipulation of the reflux ratio. The independent manipulation of the reflux rate and distillate (instead of fixed reflux ratio policy) is an important control decision for the successful regulation of the example RD column.

本文探讨了对带有惰性组分的理想假想三元反应蒸馏塔的分散控制。采用简单的启发式方法（两点和三点）设计了基于成分测量和温度推断的控制结构。本研究首次针对示例 RD 精馏塔提出了三点成分控制结构。虽然在所有的吞吐量变化中都能看到稳定的闭环响应，但在固定回流比导致的惰性成分变化中，两点式结构无法实现对底部产品纯度或馏分中惰性纯度的严格控制。三点控制结构由于可以间接控制回流比，因此在惰性成分变化方面的性能相当令人满意。独立控制回流速率和馏分（而不是固定回流比政策）是成功调节示例 RD 塔的重要控制决策。

引用次数: 0

Flow characteristics in a horizontal reactor for continuous preparation of carbon nanotubes 用于连续制备碳纳米管的水平反应器中的流动特性

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-10-02 DOI: 10.1016/j.cep.2024.110013

This study focuses on a sophisticated horizontal reactor designed to facilitate the continuous growth of carbon nanotubes (CNTs) through chemical vapor deposition (CVD). Experimental observations reveal that carbon production varies at different locations within the reactor, with higher yields typically found in the middle and rear zones. The flow dynamics within the reactor play a pivotal role in CNT growth, prompting a detailed simulation of the flow field using Computational Fluid Dynamics (CFD). This simulation leverages fluid dynamics principles to assess the impact of various parameters on the flow field, ultimately identifying the optimal operating conditions. Findings indicate that temperature-induced density contrasts create cyclic flow patterns that can negatively affect CNT growth rates. However, the gas flow inside the horizontal continuous preparation reactor can be improved and optimized by adjusting and controlling the preparation parameters. Appropriately lowering the heating temperature and the mole fraction of propylene in inlet 2, within the range of conditions suitable for the growth of CNTs, while minimizing the perturbation of the flow field by the shape of the carriers, can promote more favorable CNTs growth.

本研究的重点是一个复杂的水平反应器，其设计目的是通过化学气相沉积（CVD）促进碳纳米管（CNT）的连续生长。实验观察表明，反应器内不同位置的碳产量各不相同，通常中间和后部区域的碳产量较高。反应器内的流动动力学对碳纳米管的生长起着至关重要的作用，这促使我们使用计算流体动力学（CFD）对流场进行了详细模拟。该模拟利用流体动力学原理评估各种参数对流场的影响，最终确定最佳操作条件。研究结果表明，由温度引起的密度对比会产生循环流动模式，从而对碳纳米管的生长率产生负面影响。然而，通过调整和控制制备参数，可以改善和优化水平连续制备反应器内的气体流动。在适合 CNT 生长的条件范围内，适当降低加热温度和入口 2 中丙烯的分子分数，同时尽量减少载流子形状对流场的干扰，可以促进更有利的 CNT 生长。

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引用次数: 0

Stress-blended eddy simulation of flow characteristics in stirred tanks with different curved blade impellers 采用不同曲面叶片叶轮的搅拌槽中流动特性的应力混合涡流模拟

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-10-02 DOI: 10.1016/j.cep.2024.110015

A high-performance impeller is crucial for enhancing material mixing in a stirred tank. In this work, the flow characteristics created by different curved blade impellers including staggered fan-shaped parabolic disc turbine (SFPDT), swept-back parabolic disc turbine (SPDT), asymmetric staggered parabolic disc turbine (ASPDT) and traditional parabolic disc turbine (PDT) in stirred tanks are investigated numerically by using the stress-blended eddy simulation (SBES) model with a sliding mesh approach. After successful validation of prediction accuracy, power characteristics, mean flow, turbulence characteristics, turbulent kinetic energy (TKE) transport, and trailing vortices behaviors of SFPDT, ASPDT, SPDT and PDT in stirred tanks are systematically evaluated. The results show that ASPDT leads to a significant asymmetric distribution in the axial direction for velocity, TKE and trailing vortices, but the radial jet reduces more severely in the radial direction. The fan-shaped geometry constrains the influence of asymmetric staggered structure on the TKE and trailing vortices distribution for SFPDT. The swept-back blade structure of SPDT results in the lowest power number and TKE values level. These results provide a foundation for the further development and application of high-efficiency impellers.

高性能叶轮对于加强搅拌槽中的物料混合至关重要。本研究采用应力混合涡流模拟（SBES）模型和滑动网格方法，对搅拌槽中不同曲面叶片叶轮（包括交错扇形抛物面圆盘涡轮（SFPDT）、后掠抛物面圆盘涡轮（SPDT）、非对称交错抛物面圆盘涡轮（ASPDT）和传统抛物面圆盘涡轮（PDT））产生的流动特性进行了数值研究。在成功验证预测精度后，系统地评估了 SFPDT、ASPDT、SPDT 和 PDT 在搅拌槽中的功率特性、平均流、湍流特性、湍流动能（TKE）传输和尾涡行为。结果表明，ASPDT 会导致速度、TKE 和尾涡在轴向出现明显的不对称分布，但径向射流在径向的减少更为严重。扇形几何形状限制了不对称交错结构对 SFPDT 的 TKE 和尾涡分布的影响。SPDT 的后掠叶片结构导致了最低的功率数和 TKE 值水平。这些结果为进一步开发和应用高效叶轮奠定了基础。

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引用次数: 0

Performance analysis of photocatalytic reactor with immobilized catalyst for emerging pollutants water treatment using cfd simulation and optimization method 利用 cfd 模拟和优化方法对固定催化剂光催化反应器处理新污染物水的性能分析

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-10-01 DOI: 10.1016/j.cep.2024.110016

An annular labyrinth photocatalytic reactor design was optimized to degrade water emerging pollutants by combining CFD modeling and a Box-Benken experimental design with the desirability function method for the optimization. The optimization was performed by minimizing the pollutant degradation time and the reactor operational cost, varying three factors in the experimental design, the fins number in the labyrinth, the thickness of the annular region, and the solution transmittance. The range of variation levels was 5 to 9, 5 mm to 25 mm, and 35 % to 95 % respectively. The intrinsic kinetic model of the salicylic acid degradation used in CFD simulations takes into account the variations of pollutant concentration and light intensity. Results showed that the transmittance was the most significant factor in minimizing both degradation time and energy cost, followed by the annular reactor thickness and the fins number. The desirability method showed that the combination of the optimized reactor levels was 9 fins, thickness of 25 mm, and transmittance of 95 %. To verify the efficiency gain of the optimized reactor, it was compared the degradation time and the energy cost of the optimized reactor with a conventional annular reactor. The efficiency gain was about 53 %.

通过将 CFD 建模和箱-本肯实验设计相结合，并采用可取函数法进行优化，对环形迷宫光催化反应器的设计进行了优化，以降解水中新出现的污染物。通过改变实验设计中的三个因素，即迷宫中的鳍片数量、环形区域的厚度和溶液透过率，使污染物降解时间和反应器运行成本最小化，从而进行了优化。变化范围分别为 5 至 9、5 毫米至 25 毫米以及 35% 至 95%。CFD 模拟中使用的水杨酸降解内在动力学模型考虑了污染物浓度和光照强度的变化。结果表明，透光率是使降解时间和能源成本最小化的最重要因素，其次是环形反应器厚度和翅片数量。可取性方法显示，优化反应器水平的组合为 9 个鳍片、25 毫米厚度和 95% 的透射率。为了验证优化反应器的增效效果，比较了优化反应器与传统环形反应器的降解时间和能源成本。效率提高了约 53%。

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引用次数: 0