Weblabs in Chemical Engineering Education

The idea for this paper resulted from a workshop on the use of remotely operated experiments (weblabs) in chemical engineering education held in Cambridge, UK, in July 2005 (http://como.cheng.cam.ac.uk/conf.workshop.html). At the workshop people using weblabs met to discuss experiences and different approaches on how to make the most out of remote experiments in undergraduate chemical engineering teaching.We describe the technology involved in making educational experiments available on the internet and how they are motivated and used in teaching at MIT, the University of Cambridge and the University of Leipzig. Experiences are discussed and we give our view of the strengths and weaknesses of weblabs in chemical engineering education.     

Thermodynamic optimization of energy transfer in (bio)chemical reaction systems

The engineering science literature on energy-transfer processes (heat engines, heat pumps, etc.) for the production of mechanical energy, electricity, cold or heat has produced some remarkable results on maximum power and efficiency optimization. We have wondered in how far these results can be extended to include chemical reaction systems to describe living and possibly future-industrial energy-transfer systems. With elements of non-linear irreversible thermodynamics and chemical kinetics, we have arrived at some interesting results on optimizing the performance of chemical energy transfer. We discuss thermodynamic efficiency, energy-transfer rate, entropy-generation rate, and optimum-performance characteristics of (bio)chemical energy transfer.     

Influence of Vibrations on Gas Bubble Formation in Liquids

The formation and motion of gas bubbles, and more especially the size of the bubbles formed, are important factors in many chemical engineering processes. In the present paper we describe the influence of vibration on bubble size and establish that the energy transferred from the vibrating channel to the bubbles is well correlated to the speed of vibration. We present a new model for determining and controlling bubble size and report results of experiments showing a high degree of compatibility between experimental results and the mathematical model and confirming the suitability of the model for engineering design applications.     

化工仿真培训系统

借助计算机,应用化工仿真培训系统来描述化工过程。硬件包括两套仿真系统,软件由系统软件、仿ＤＣＳ软件、典型的化工单元与装置级软件构成     

Closed-form solution to the problem of reaction with fixed bed adsorption using delay-differential equations

Delay-differential equations (DDEs) can describe many chemical engineering models. However, the formalism of DDEs appears to be underutilized in chemical engineering. We have recast the canonical chemical engineering problem of batch reaction with fixed bed sorption into the form of a delay-differential equation, obtaining a more intuitive model and a simpler closed form solution than those previously reported. Considerable model reduction is possible through the use of DDE formalism when one considers that chemical processes can be partially represented by networks of transportation and state delays. Analytical and numerical methods for solution, as well as controllability and stability theory for systems of DDEs, are nearly as rich and developed as those for ordinary differential equations. Significant progress thus may be possible in areas such as the modeling, synthesis, and control of chemical processes, if the governing equations can be expressed in the form of delay-differential equations.     

Machine learning for molecular thermodynamics

Thermodynamic properties of complex systems play an essential role in developing chemical engineering processes. It remains a challenge to predict the thermodynamic properties of complex systems in a wide range and describe the behavior of ions and molecules in complex systems. Machine learning emerges as a powerful tool to resolve this issue because it can describe complex relationships beyond the capacity of traditional mathematical functions. This minireview will summarize some fundamental concepts of machine learning methods and their applications in three aspects of the molecular thermodynamics using several examples. The first aspect is to apply machine learning methods to predict the thermodynamic properties of a broad spectrum of systems based on known data. The second aspect is to integer machine learning and molecular simulations to accelerate the discovery of materials. The third aspect is to develop machine learning force field that can eliminate the barrier between quantum mechanics and all-atom molecular dynamics simulations. The applications in these three aspects illustrate the potential of machine learning in molecular thermodynamics of chemical engineering. We will also discuss the perspective of the broad applications of machine learning in chemical engineering.     

化学工程科学发展的回顾与思考

简述了化学工程科学发展的主要成果,重点介绍了近期发展的“产品工程”,化学工程中的尺度问题及化工过程“场”和“流”分析等方面的进展及其对化学工程科学内容的贡献;提出以“质量传递与转化”,“能量传递与转化”及“信息传递与转化”来描述现代化学工程学科体系。本文还对我国化工科学及产业发展进行了展望。     

基于Aspen-Plus的化工热力学教学(Ⅰ)均相性质计算

化工热力学作为化学工程的基础学科,是化学工程与工艺专业的一门核心课程,在化学工程的教学过程中占有极其重要的地位。借助专业化工模拟软件Aspen-Plus完成化工热力学教学中的相关性质计算,可以得到较为理想的结果,为加强应用能力培养提供了基础。     

A model predictive control package for undergraduate education

Model predictive control (MPC) techniques are extremely profitable control strategies and are well accepted in the chemical processing industry so it is important that chemical engineering graduates have a fundamental understanding of MPC. This understanding will help them make contributions in industry where these control strategies abound. Without such knowledge, graduates would not understand a major part of the control structure present in modern manufacturing systems and would have difficulty understanding how to modify and improve those chemical manufacturing systems to take advantage of new technology.In this paper we describe a new software package developed and tested by the authors for teaching undergraduates the fundamentals of MPC including its suggested application in the classroom. The package is similar to existing industrial model predictive control packages in that the same steps are required to implement a model predictive controller as follows: model identification, controller configuration, controller simulation and tuning. We describe our experience using the package to introduce MPC to an advanced undergraduate process control II class. The package has also been used to provide an MPC laboratory experience for a graduate class on industrial process control.     

聚焦结构、界面与多尺度问题,开辟化学工程的新里程

20世纪90年代以来,随着计算机技术和测量仪器的迅速发展,化学工程的研究水平日益提升,由经验规则的判断逐渐提高到计算机模拟量化分析. 化学工程的研究范围也日益扩大,下至纳微尺度结构与界面的观察与量化,上至宏观尺度设备与工厂的系统集成. 化学工程的服务对象也由化学工业扩展到冶金、材料、能源、环境、生物等诸多进行物质转化的过程工业. 目前化工科技界正在呼吁寻求继第一里程单元操作、第二里程传递过程和化学反应工程之后的第三里程. 化学工程中以往惯用的忽视非均匀多尺度结构和界面存在的平均方法是造成预测偏差和调控、放大困难的主要原因. 必须关注结构、界面和多尺度问题,研究多尺度结构、界面的量化预测理论和优化调控方法,建立多尺度结构、界面与"三传一反"的关系模型,与当代先进的计算方法、计算流体力学和计算机模拟相结合,有望解决化工过程与设备的优化调控与放大的难题,成为化学工程发展的新里程.     

聚丙烯腈基碳纤维原丝在干湿法纺丝中溶剂扩散过程的研究

聚丙烯腈基碳纤维具有高强度、高模量、耐高温、耐腐蚀的优良性能,广泛应用于化工、机械、造船等方面。在聚丙烯腈基碳纤维的干湿法纺丝中,纺丝原液进入凝固浴后发生的溶剂扩散过程对聚丙烯腈基碳纤维原丝的结构和性能有重要影响。通过Fick定律建立了纺丝液溶剂扩散的数学模型,得出了溶剂沿纤维原丝的径向分布,还讨论了各种因素对溶剂质量分数分布的影响。     

HAZOP分析方法在化工原理实验教学中的应用

化工原理实验是促进学生理解化工单元操作、培养学生工程实践能力的一门重要课程,而化工安全是其中必不可少的教学内容。为适应新工科教学改革的需要,文章提出将HAZOP分析方法引入化工原理实验教学中,介绍了针对化工原理实验装置进行HAZOP分析的方法和流程,并以“圆形直管中气体对流传热系数的测定”实验项目为例,介绍了其应用过程。实践表明,HAZOP安全分析方法用于化工原理实验教学能够巩固和加深学生对理论知识的理解,培养学生的创新意识和安全意识,提高学生分析和解决复杂工程问题的能力。     

通风方式对化工车间火灾影响的实例分析

在分析化工企业火灾危险性的基础上,建立了化工车间火灾危险度分析数学模型。根据工程实际,分别对正常工业通风和火灾后事故通风工况进行了火灾危险度计算。计算结果表明事故通风及防排烟系统启动后,能有效的降低车间的火灾危险性等级。研究结果用于指导化工厂通风系统设计及提高消防安全管理水平。     

浅谈我校《化工原理》教学改革

《化工原理》课是化工类所有专业都开设的一门工程性极强的技术基础课。化工原理课包括了课堂理论教学、课程设计和实验三个教学环节。在这三个环节中,我们改变传统的教学方法,充分利用多媒体课件,通过对化工单元操作的基本规律的学习,将帮助学生树立牢固的工程观点,培养解决工程实际问题的综合能力。     

基于EMMS范式的离散模拟及其化工应用

化工过程通常涉及化学、化工、过程系统工程3个层次,而每个层次又包含微尺度、介尺度和宏尺度,如化工层次的颗粒、颗粒团和反应器尺度。每个层次中的微尺度单元都自然适用离散模型,即通过跟踪每个单元的运动获得整个体系演化的宏观规律。但由于单元数量巨大,工程模拟往往依赖经过统计平均的连续介质模型。由此带来的精度问题,特别是忽略了介尺度结构的问题,随着对化工过程效率和绿色度等要求的提高而日渐突出。介绍了通过问题、模型、软件和硬件结构的一致性提升离散模拟的精度、能力和效率的方法、进展及其在复杂分子体系、颗粒流、气固流态化等方面的应用,展示了通过离散模拟实现虚拟过程工程的可能性。     

Natural and Genetically Engineered Proteins for Tissue Engineering

To overcome the limitations of traditionally used autografts, allografts and, to a lesser extent, synthetic materials, there is the need to develop a new generation of scaffolds with adequate mechanical and structural support, control of cell attachment, migration, proliferation and differentiation and with bio-resorbable features. This suite of properties would allow the body to heal itself at the same rate as implant degradation. Genetic engineering offers a route to this level of control of biomaterial systems. The possibility of expressing biological components in nature and to modify or bioengineer them further, offers a path towards multifunctional biomaterial systems. This includes opportunities to generate new protein sequences, new self-assembling peptides or fusions of different bioactive domains or protein motifs. New protein sequences with tunable properties can be generated that can be used as new biomaterials.In this review we address some of the most frequently used proteins for tissue engineering and biomedical applications and describe the techniques most commonly used to functionalize protein-based biomaterials by combining them with bioactive molecules to enhance biological performance. We also highlight the use of genetic engineering, for protein heterologous expression and the synthesis of new protein-based biopolymers, focusing the advantages of these functionalized biopolymers when compared with their counterparts extracted directly from nature and modified by techniques such as physical adsorption or chemical modification.     

化工原理课程教学方法探讨

化工原理是化工、环境类各专业的一门重要的技术基础课。要提高化工原理理论课的教学效果,必须改变以往单向传输的教学方法。根据化工原理课程的特点和笔者的教学经验,教师在授课过程中灵活运用对比式、情境式、多媒体辅助式、归纳总结式等教学方法,可以取得令人满意的教学效果,达到事半功倍的作用。