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A novel fault diagnosis framework empowered by LSTM and attention: A case study on the Tennessee Eastman process 利用 LSTM 和注意力的新型故障诊断框架:田纳西伊士曼工艺案例研究
Pub Date : 2024-08-22 DOI: 10.1002/cjce.25460
Shuaiyu Zhao, Yiling Duan, Nitin Roy, Bin Zhang
In the era of Industry 4.0, substantial research has been devoted to the field of fault detection and diagnosis (FDD), which plays a critical role in preventive maintenance of large chemical processes. However, the existing studies are primarily focused on few‐shot samples of process data and without considering the role of activation functions in temporal diagnostic tasks. In this paper, an end‐to‐end chemical fault diagnosis framework that combines bidirectional long short‐term memory (LSTM) with attention mechanism is proposed. In the preprocessing stage, a special sliding time window function is developed to integrate multivariate samples containing complex temporal information via operation such as subset extraction. Afterwards, the bidirectional LSTM is constructed to address dynamic and temporal relationship on longer series observation, and the attention mechanism is adopted to highlight key fault features by assigning different attention weights. A case application is performed on the enriched Tennessee Eastman process (TEP), which reduces the bias between sample statistics and larger population parameters compared to existing few‐shot sample studies. The metric evaluation experiments for six activations show that the model configured with tanh function can achieve the optimal tradeoff in chemical process tasks, providing a strong benchmark for subsequent fault diagnosis research.
在工业 4.0 时代,对故障检测和诊断(FDD)领域进行了大量研究,该领域在大型化工流程的预防性维护中发挥着至关重要的作用。然而,现有的研究主要集中在过程数据的少量样本上,并没有考虑激活函数在时间诊断任务中的作用。本文提出了一种结合双向长短期记忆(LSTM)和注意力机制的端到端化学故障诊断框架。在预处理阶段,开发了一种特殊的滑动时间窗函数,通过子集提取等操作整合包含复杂时间信息的多元样本。然后,构建双向 LSTM 来处理较长序列观测的动态和时间关系,并采用注意力机制,通过分配不同的注意力权重来突出关键故障特征。在丰富的田纳西伊士曼过程(Tennessee Eastman process,TEP)上进行了案例应用,与现有的少量样本研究相比,TEP 减少了样本统计数据与更大群体参数之间的偏差。六个激活的度量评估实验表明,配置 tanh 函数的模型可以在化学过程任务中实现最优权衡,为后续故障诊断研究提供了强有力的基准。
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引用次数: 0
The use of graphene nanoplatelet‐embedded PA‐6 nanofibres to remove turbidity from water 使用嵌入石墨烯纳米小板的 PA-6 纳米纤维去除水中的浊度
Pub Date : 2024-08-22 DOI: 10.1002/cjce.25469
Ahmet Alp Zembat, Elifnur Gezmis‐Yavuz, Derya Y. Koseoglu‐Imer, C. Elif Cansoy
The global challenge of providing clean water at an affordable cost has led to the need for the development of low‐cost and non‐toxic materials for the treatment and recycling of waste water. Nanofibres have emerged as a promising solution due to their superior properties. To this end, composite polyamide‐6 (PA‐6) nanofibres embedded with graphene nanoplatelets (GNPs) were prepared by electrospinning. The study investigated the effect of the ratio of GNPs, which ranged from 0.1 to 1.0 wt.%, on the mechanical properties of nanofibres and the removal of turbidity. The results showed that PA‐6 nanofibres with 0.5 wt.% GNP exhibited enhanced mechanical properties, and increasing the GNP ratio led to lower turbidity values. To the best of our knowledge, GNP‐embedded PA‐6 nanofibres have not been used for turbidity removal before, and these filter materials are promising due to their excellent fibre structure, mechanical strength, and high level of turbidity removal.
以可承受的成本提供清洁水是一项全球性挑战,因此需要开发低成本、无毒的材料来处理和回收废水。纳米纤维因其卓越的性能而成为一种前景广阔的解决方案。为此,研究人员通过电纺丝法制备了嵌入石墨烯纳米片(GNPs)的复合聚酰胺-6(PA-6)纳米纤维。研究调查了 GNPs 的比例(0.1-1.0 wt.%)对纳米纤维机械性能和去除浊度的影响。结果表明,含有 0.5 wt.% GNP 的 PA-6 纳米纤维具有更高的机械性能,而增加 GNP 的比例可降低浊度值。据我们所知,包埋 GNP 的 PA-6 纳米纤维以前从未用于去除浊度,这些过滤材料因其优异的纤维结构、机械强度和高水平的浊度去除率而大有可为。
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引用次数: 0
Nonlinear dynamic process monitoring based on latent mapping embedding deep neural networks 基于潜在映射嵌入深度神经网络的非线性动态过程监控
Pub Date : 2024-08-22 DOI: 10.1002/cjce.25461
Zhenhua Yu, Wenjing Wang, Xueting Wang, Qingchao Jiang, Guan Wang
In industrial processes, complex nonlinearity and dynamics generally exist, making it challenging to achieve good results using conventional process monitoring methods. In this paper, a latent mapping embedding neural network method (LMNN) is proposed for efficient monitoring of nonlinear dynamic processes. First, a deep neural network (DNN) is employed to acquire features of state variables from nonlinear process data and expand them along with the input to a new feature subspace. Second, a latent mapping (LM) method is used to map the high‐dimensional feature subspace to a low‐dimensional subspace that includes the most beneficial time series information. Then the entire neural network and regression parameters are obtained through an end‐to‐end learning manner, through which the nonlinearity and process dynamics are well characterized. Subsequently, prediction error‐based residual is generated and the monitoring model is established. The performance of the proposed method is verified through a simulation of penicillin production process and an actual fermentation process of penicillin. Comparisons with state‐of‐the‐art methods are carried out, and results validate the effectiveness and superiority of the proposed method.
在工业流程中,一般都存在复杂的非线性和动态性,因此使用传统的流程监控方法很难取得良好的效果。本文提出了一种潜映射嵌入神经网络方法(LMNN),用于高效监测非线性动态过程。首先,采用深度神经网络(DNN)从非线性过程数据中获取状态变量的特征,并将其与输入一起扩展到一个新的特征子空间。其次,使用潜映射(LM)方法将高维特征子空间映射到包含最有用时间序列信息的低维子空间。然后,通过端到端学习方式获得整个神经网络和回归参数,从而很好地表征非线性和过程动态。随后,生成基于预测误差的残差,并建立监测模型。通过模拟青霉素生产过程和实际的青霉素发酵过程,验证了所提方法的性能。与最先进的方法进行了比较,结果验证了所提方法的有效性和优越性。
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引用次数: 0
Pressure loss in packed beds of multicomponent mixtures of flat particles with particle overlap, including random chips 有颗粒重叠的扁平颗粒多组分混合物(包括随机切屑)填料床的压力损失
Pub Date : 2024-08-22 DOI: 10.1002/cjce.25471
Evangelina Schonfeldt, William L. H. Hallett
wPressure loss measurements are presented for packed beds of multi‐component mixtures of thin angular parallelepipeds and of random wood chips for a Reynolds number range of 50 to 500. For flat particles like these, the degree to which the particles overlap is an essential factor in pressure loss, and this was measured using two different methods, including a novel technique involving progressive dismantling and photography of the bed. The experimental friction factors were found to be well represented by the Nemec and Levec pressure loss correlation, an Ergun‐type equation with an explicit dependence of the parameters on particle sphericity, with the equation expanded to include the effects of particle overlap and of packing anomalies at the wall. The friction losses of the mixtures were found to be somewhat higher than those of the individual component particles, requiring a minor change in the correlation parameters. Estimates of the tortuosity of the bed channels showed that the greater losses of the mixtures correspond to an increase in tortuosity.
w 本文介绍了在雷诺数为 50 到 500 的范围内,对多组分薄角平行椭圆形混合物和随机木屑的填料床进行的压力损失测量。对于像这样的扁平颗粒,颗粒的重叠程度是压力损失的一个重要因素,我们使用两种不同的方法测量了这一因素,包括一种涉及床层逐步拆卸和拍照的新技术。实验发现,Nemec 和 Levec 压力损失相关性很好地反映了实验摩擦因数,这是一个厄尔贡式方程,其参数与颗粒球度有明确的关系,方程扩展后包括了颗粒重叠和壁面填料异常的影响。结果发现,混合物的摩擦损耗略高于单个成分颗粒的摩擦损耗,因此需要对相关参数稍作修改。对床层通道曲折度的估算表明,混合物的更大损失与曲折度的增加相对应。
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引用次数: 0
Three‐layer deep learning network random trees for fault detection in chemical production process 用于化工生产过程故障检测的三层深度学习网络随机树
Pub Date : 2024-08-19 DOI: 10.1002/cjce.25465
Ming Lu, Zhen Gao, Ying Zou, Zuguo Chen, Pei Li
With the development of technology, the chemical production process is becoming increasingly complex and large‐scale, making fault detection particularly important. However, current detection methods struggle to address the complexities of large‐scale production processes. In this paper, we integrate the strengths of deep learning and machine learning technologies, combining the advantages of bidirectional long‐ and short‐term memory neural networks, fully connected neural networks, and the extra trees algorithm to propose a novel fault detection model named three‐layer deep learning network random trees (TDLN‐trees). First, the deep learning component extracts temporal features from industrial data, combining and transforming them into a higher‐level data representation. Second, the machine learning component processes and classifies the features extracted in the first step. An experimental analysis based on the Tennessee Eastman process verifies the superiority of the proposed method.
随着技术的发展,化工生产过程越来越复杂,规模也越来越大,因此故障检测显得尤为重要。然而,目前的检测方法难以应对大规模生产过程的复杂性。本文整合了深度学习和机器学习技术的优势,结合双向长短期记忆神经网络、全连接神经网络和额外树算法的优点,提出了一种名为三层深度学习网络随机树(TDLN-trees)的新型故障检测模型。首先,深度学习组件从工业数据中提取时间特征,将其组合并转换为更高层次的数据表示。其次,机器学习组件对第一步提取的特征进行处理和分类。基于田纳西伊士曼流程的实验分析验证了所提方法的优越性。
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引用次数: 0
Properties of blends of amorphous and semicrystalline PLAs containing multiwalled carbon nanotubes 含有多壁碳纳米管的无定形和半结晶聚乳酸混合物的性能
Pub Date : 2024-08-19 DOI: 10.1002/cjce.25463
Mojtaba Mohammadi, Mohammadreza Nofar, Pierre J. Carreau
Blend nanocomposites of amorphous polylactide (aPLA) and semicrystalline PLA (scPLA)‐multiwalled carbon nanotubes (MWCNTs) were prepared by a twin‐screw extruder below the melting temperature of the scPLA. The maximum weight percent of MWCNTs in the blends was 0.9 wt.%. The extrudates were either pelletized immediately or after drawing at a drawing ratio of about 10. According to small amplitude oscillatory shear rheological analysis, the rheological properties of the aPLA/scPLA (85/15 wt.%) drawn sample were significantly increased compared to the undrawn samples. With the presence of MWCNTs, more crystallites could develop in the scPLA, and the electrical conductivity of the aPLA/scPLA nanocomposites was reduced due to the encapsulation of MWCNTs within the crystallites of scPLA. Increasing the temperature during compression moulding to 190°C, which is above the melting temperature of the scPLA, effectively removed this obstacle and the electrical conductivity was increased by a factor of up to 106 compared to the samples moulded at 150°C.
通过双螺杆挤压机在低于半结晶聚乳酸(scPLA)熔化温度的条件下制备了无定形聚乳酸(aPLA)和半结晶聚乳酸(scPLA)-多壁碳纳米管(MWCNTs)的共混纳米复合材料。混合物中 MWCNTs 的最大重量百分比为 0.9 wt.%。挤出物或立即造粒,或在拉丝后以约 10 的拉丝比造粒。根据小振幅振荡剪切流变分析,与未拉丝样品相比,拉丝 aPLA/scPLA (85/15 wt.%)样品的流变特性显著提高。由于 MWCNTs 的存在,scPLA 中可以形成更多的结晶,并且由于 MWCNTs 被包裹在 scPLA 的结晶中,aPLA/scPLA 纳米复合材料的导电性降低。将压缩模塑过程中的温度提高到 190°C(高于 scPLA 的熔化温度)可有效消除这一障碍,与在 150°C 下模塑的样品相比,导电性提高了 106 倍。
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引用次数: 0
Numerical study of gas–solid flow characteristics of cylindrical fluidized beds based on coarse‐grained CFD‐DEM method 基于粗粒度 CFD-DEM 方法的圆柱流化床气固流动特性数值研究
Pub Date : 2024-08-15 DOI: 10.1002/cjce.25455
Zhong Tang, Zhenzhong Li, Shanglong Huang, Chen Yang
The existing researches lack the comprehensive comparison of the performance of two‐fluid model (TFM) and computational fluid dynamics‐discrete element model (CFD‐DEM) using a cylindrical fluidized bed as a research object. In addition, the applicability of rotational periodic boundary conditions in CFD‐DEM simulations of cylindrical fluidized beds is still unclear. Therefore, taking cylindrical fluidized bed as the object and studying the performance of different simulation methods can provide guidance for the selection of simulation methods in subsequent related studies. In the present study, TFM and coarse‐grained CFD‐DEM were used in simulations of the fluidized bed to evaluate the performance of different numerical methods. Furthermore, the applicability of rotating periodic boundary conditions in CFD‐DEM simulations was investigated. The results show that TFM and coarse‐grained CFD‐DEM perform in general agreement in predicting macro variables (e.g., overall pressure drop and bed height). However, radial void fraction distribution and void fraction probability density function (PDF) distribution of CFD‐DEM agreed better with the experimental data. CFD‐DEM simulations with rotational periodic boundary conditions applied showed lower predicted void fraction PDF peaks at packed bed heights and poorly modelling particle mixing in the central of cylindrical fluidized bed due to changes in the boundary conditions as well as the number of particle parcels. Therefore, both TFM and CFD‐DEM can obtain reasonable macro variables, but CFD‐DEM predicted more accurate gas–solid two‐phase distribution. The CFD‐DEM with rotating periodic boundary conditions could not reasonably predict the pressure drop and gas–solid two‐phase distribution inside the cylindrical fluidized bed.
现有研究缺乏以圆柱流化床为研究对象,对双流体模型(TFM)和计算流体力学-离散元模型(CFD-DEM)性能的全面比较。此外,旋转周期性边界条件在圆柱流化床 CFD-DEM 模拟中的适用性仍不明确。因此,以圆柱流化床为研究对象,研究不同模拟方法的性能,可以为后续相关研究中模拟方法的选择提供指导。本研究采用 TFM 和粗粒度 CFD-DEM 对流化床进行模拟,以评估不同数值方法的性能。此外,还研究了旋转周期边界条件在 CFD-DEM 模拟中的适用性。结果表明,TFM 和粗粒度 CFD-DEM 在预测宏观变量(如总压降和床层高度)方面的表现基本一致。然而,CFD-DEM 的径向空隙率分布和空隙率概率密度函数 (PDF) 分布与实验数据更为吻合。应用旋转周期性边界条件的 CFD-DEM 模拟显示,由于边界条件和颗粒包裹数的变化,在填料床高度处预测的空隙率概率密度函数峰值较低,对圆柱流化床中心的颗粒混合模拟较差。因此,TFM 和 CFD-DEM 都能获得合理的宏观变量,但 CFD-DEM 预测的气固两相分布更为精确。采用旋转周期边界条件的 CFD-DEM 无法合理预测圆柱流化床内的压降和气固两相分布。
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引用次数: 0
Optimizing hydrothermal carbonization for enhanced energy production from algal biomass with high moisture content 优化水热碳化技术,提高高含水量藻类生物质的能源产量
Pub Date : 2024-08-15 DOI: 10.1002/cjce.25457
Kanta Nakano, Numan Luthfi, Takashi Fukushima, Kenji Takisawa
Recently, the depletion of fossil fuels has become an issue, prompting the search for sustainable alternatives. Algal biomass has gained considerable attention as a promising renewable energy source because of its high production efficiency and adaptability to external environment. However, its high‐moisture content escalates the energy requirement during the thermal drying process in algal biomass production. Thus, we proposed a new energy production system using hydrothermal carbonization, which requires no pretreatment even for high moisture content biomass, making it compatible with such materials. Herein, we investigated the decrease in moisture content of algal biomass through hydrothermal carbonization and its effect on the energy production and energy balance of algal biomass. The results showed that hydrothermal carbonization at 240°C for 3 h produced hydrochar with a moisture content of 34.6%. It was found that it was due to changes in surface structures, such as CH, CO, and OH functional groups, using scanning electron microscopy (SEM) and Fourier transform infrared (FT‐IR) analysis. However, the greatest reduction in production energy, 45%, was achieved at 240°C for 4 h. The optimal energy balance was obtained for hydrothermal carbonization at 220°C for 4 h, for which energy production was 2.7 times more efficient than that achieved by conventional methods.
近来,化石燃料的枯竭已成为一个问题,促使人们寻找可持续的替代能源。藻类生物质作为一种前景广阔的可再生能源,因其生产效率高、对外部环境适应性强而备受关注。然而,藻类生物质含水量高,在热干燥过程中对能源的需求也随之增加。因此,我们提出了一种利用水热碳化技术的新型能源生产系统,该系统即使对高水分含量的生物质也无需进行预处理,因此与此类材料兼容。在此,我们研究了通过水热碳化降低海藻生物质含水量及其对海藻生物质能源生产和能源平衡的影响。结果表明,240°C 水热碳化 3 小时产生的水炭含水量为 34.6%。利用扫描电子显微镜(SEM)和傅立叶变换红外(FT-IR)分析发现,这是由于表面结构发生了变化,如CH、CO和OH官能团。水热碳化法在 220°C 下进行 4 小时可获得最佳能量平衡,其能量生产效率是传统方法的 2.7 倍。
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引用次数: 0
Coalescence investigations in a small‐scale continuously operated setup for bubble column design 用于气泡塔设计的小型连续运行装置中的聚合研究
Pub Date : 2024-08-14 DOI: 10.1002/cjce.25458
Mark Werner Hlawitschka, Andreas Schleiffer, Jonas Schurr, Stephan Winkler, Daniel Danner
A novel micro‐channel technique for analyzing the coalescence of bubbles and obtaining relevant information for the creation of a coalescence database is presented. The micro‐channel improves the coalescence investigations by a continuously operated setup, reduces the accumulation of impurities and increases the amount of recorded data. To introduce the new setup, studies with alcoholic, electrolytic aqueous systems and liquid silicone oil as a second liquid are presented, showing the influence of different concentrations. Artificial intelligence has been successfully developed to automate data generation. This approach improves the understanding of bubble coalescence by introducing a reproducible setup. Furthermore, it facilitates the transition to a predictive column design through data‐based decisions and modelling.
本文介绍了一种新型微通道技术,用于分析气泡凝聚并获取相关信息以创建凝聚数据库。微通道通过连续运行的装置改进了凝聚研究,减少了杂质的积累,并增加了记录的数据量。为了介绍新的装置,介绍了酒精、电解水系统和作为第二种液体的液态硅油的研究,显示了不同浓度的影响。人工智能已成功开发用于自动生成数据。这种方法通过引入可重复的设置,提高了对气泡凝聚的理解。此外,它还有助于通过基于数据的决策和建模过渡到预测性色谱柱设计。
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引用次数: 0
Fluidized bed applications and modern scale‐up tools for the energy transition 流化床应用和现代放大工具促进能源转型
Pub Date : 2024-07-16 DOI: 10.1002/cjce.25420
Todd Pugsley
Fluidized bed technology has a 100‐year history of delivering energy solutions to the world. Examples include fluid catalytic cracking, coal combustion and gasification, and fluid coking. Moving forward, fluidization technology has the potential to underpin the development of entirely new sustainable processes in the energy transition and the circular economy and many of these will be advanced by small‐and‐medium enterprises (SMEs) and start‐ups. Focused, low‐cost, and time‐bound research outcomes will be needed to support these SMEs as they bring their new technologies to market as quickly as possible. This paper first summarizes some of the fluidized bed technologies that will play a key role in the energy transition and then considers how the strategic concept of discovery driven growth can lead to focused, rapid, and low‐cost information. The experimental data can then be used to develop hybrid models using machine learning methods that will be more robust, accurate, and reliable models. With focused, interdisciplinary research, fluidization models may be developed that would allow fluidized beds to go directly from lab or pilot scale directly to commercial. This would reduce development costs and timelines dramatically, hence bringing these new technologies to market more quickly. Early commercialization will allow the environmental benefits to begin to accrue earlier and will improve returns on investment.
流化床技术为全球提供能源解决方案已有百年历史。这方面的例子包括流化催化裂化、煤炭燃烧和气化以及流化焦化。展望未来,流化床技术有可能为能源转型和循环经济中全新的可持续工艺的发展提供支持,其中许多工艺将由中小型企业(SMEs)和初创企业推进。需要有重点、低成本和有时限的研究成果来支持这些中小型企业尽快将其新技术推向市场。本文首先总结了一些将在能源转型中发挥关键作用的流化床技术,然后探讨了 "发现驱动增长 "这一战略概念如何能够带来重点突出、快速和低成本的信息。实验数据随后可用于利用机器学习方法开发混合模型,这些模型将更加稳健、准确和可靠。通过重点突出的跨学科研究,可以开发出流化模型,使流化床从实验室或中试规模直接走向商业化。这将大大减少开发成本和时间,从而更快地将这些新技术推向市场。早期商业化将使环境效益更早开始累积,并将提高投资回报率。
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引用次数: 0
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The Canadian Journal of Chemical Engineering
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