Festschrift in Honor of the 90th Birthday of Prof. Chen Jiayong

Prof. Jiayong (Chia-yung) Chen is a famous scientist of chemicalengineering and a pioneer of hydrometailurgical discipline in China. He hasmade many important contributions to the development of chemical engineeringof China. Prof. J.Y. Chen was born in a scholarly family in Jintang county of Sichuanprovince in 1922.     

Trends in chemical engineering education: Process, product and sustainable chemical engineering challenges

Teaching chemical engineering has always been faced with a dilemma: either keep in touch with industry needs or incorporate new scientific concepts into the curriculum. In this paper, a short historical analysis of the evolution of chemical engineering teaching is presented and the recent trends of the two previous facets (industry and science) are briefly reviewed. The process vs product engineering concept is proposed as one of the means to achieve a better alignment between the curriculum and industry needs. A chemical engineering teaching framework, based in part on a product and a process oriented component, which has been in place in our department 5 years ago, is described and discussed. The concept of sustainable chemistry, including process and product considerations, which can be seen as the next frontier in chemical engineering education, is finally analysed from the education point of view.     

Experimental methods in chemical engineering: Rheometry

Rheometry is an experimental technique that measures the relationship between stresses, strains, and their derivatives of fluids and deformable materials. Capillary and Couette viscometers were among the first instruments used to study rheology but now sophisticated shear and extensional rheometers are widely available for quality control, research, and product development. Here, we introduce the basics of rheology, define material functions, and describe conventional instruments, physical principles, applications, and uncertainties. In 2016 and 2017, the Web of Science indexed 8400 articles that mention rheometry and a bibliometric map assigned the keywords into five clusters of research: behaviour and viscosity, mechanical properties and morphology, rheological properties and microstructure, polymers and nano-particles, and visco-elastic properties and mixtures. Journal of Rheology, Construction Building Materials, Food Hydrocolloids, Soft Matter, Rheologica Acta, and Journal of Applied Polymer Science publish at least 80 articles per year that mention rheometry.     

Celebrating singularities: Mathematics and chemical engineering

The authors review and project their group's work in reaction engineering, electrokinetics, thin‐film lubrication/wetting, biosensing, mass spectrometry, etc., that share one common mathematical underpinning: singularities. These can be geometric singularities of actual surfaces or objects, where focused electrical, acoustic, optical and shear‐stress fields produce anomalous physical phenomena that have been explored mathematically with a spectral theory or exploited for specific applications. They are also singularities of mathematical manifolds, such as solution branches and Riemann manifolds, defined by abstract mathematical formulations, so that they can be used to design optical sensors, and understand nonlinear dynamical behavior that is relevant to system control and surface characterization. The common mathematical framework for these diverse topics underscores how mathematics can reveal, organize and inspire real and industrially relevant problems in chemical engineering. © 2013 American Institute of Chemical Engineers AIChE J, 59: 1830–1843, 2013     

Particles and suspensions in chemical engineering: Accomplishments and prospects

The role of particles and suspensions in many process of technologies and how chemical engineers encounter them are briefly described. Trends in academic chemical engineering research are discussed where it is argued that a focus on fundamentals has driven choice of research problems away from technology. Examples of contributions by chemical engineers to advances in basic understanding and technologies are given. The paper concludes with suggestions of current and future problem areas where chemical engineering research will have an impact.     

Experimental methods in chemical engineering: Raman spectroscopy

When photons impinge on a substrate, most scatter with the same frequency (elastic scattering or Rayleigh dispersion) and only 10^?7 scatter with a different energy (inelastic scattering). This inelastic interaction (Raman scattering) exchanges energy in the region of molecular vibrational transitions for crystalline and amorphous materials. Raman bands in a spectra represent vibrational transitions, like infrared, however the selection rules are different. Typically, the vibrations that are intense in Raman are weak in infrared and vice versa. A remarkable feature of the Raman effect is that it is highly sensitive to nanocrystals, even below 4 nm, which are too small to generate XRD patterns. Plasmonic enhancement, like surface‐enhanced Raman spectroscopy (SERS) boost the Raman signal by 10⁴, providing single‐molecule detection capability. Glass, quartz, and sapphire are transparent to Raman effect (depending on the energy of the incident excitation radiation), which makes it ideal to examine materials under reaction conditions (in‐situ cells and operando reactors that operate over a broad range of temperature, pressures, and environments). Raman spectroscopy emerged in the 1930s; however, infrared spectrometry displaced it. With the advent of powerful lasers in the 1970s, more researchers began to apply Raman routinely. In 2019, the Web of Science indexed 20 400 articles mentioning Raman against 50 000 articles mentioning infrared. Chemical engineers apply Raman less frequently than in material science, physical chemistry, and applied physics, with 887 articles vs 6250, 3700, and 3510 for the other disciplines. A bibliometric analysis identified four research clusters centred on thin films and optics, graphene and nanocomposites, nanoparticles and SERS, and photocatalyst.     

Experimental methods in chemical engineering: Process simulation

Process simulation software designs equipment, simulates operations, optimizes a plant's configuration (heat exchangers network, for example), estimates operating and capital expenses, and serves as an educational tool. However, mastering the theoretical background minimizes common mistakes such as applying an incorrect thermodynamic method, selecting improper algorithms in the case of tear systems, and setting irrational system specifications. Engineers and researchers will exploit this tool more often in the future as constant advancements in simulation science as well as new models are released continually. Process simulators make it easier to build digital twins and thus will facilitate the implementation of the industry 4.0 guidelines. We highlight the mathematical and technical features of process simulators, as well as the capabilities and the fields of application. A bibliometric map of keywords from articles citing Aspen+, Aspen plus, Hysys, and Pro/II indexed by Web of Science between 2017 and 2020 identified the main research clusters, such as design, optimization, energy or exergy, biomass; H₂ and CO₂ capture, thermodynamics; and separations and techno-economic analysis.     

分子模拟与化学工程

从分子水平来研究化工过程及产品的开发和设计是21世纪化学工程的一个重要方向.综述了计算机分子模拟中的MonteCarlo分子模拟和分子动力学模拟两种方法及其在化工中的应用,涉及分子模拟在建立状态方程和研究分子微观结构、相界面、扩散性质等方面的应用进展.指出分子模拟对化学工程的基础研究、工艺过程以及新产品开发将发挥巨大作用.     

Solvation and chemical engineering thermodynamics

With the continued advances in computational chemistry, solvation calculation from first principle methods is becoming a promising route for phase equilibrium modeling. However, except in a few instances, such an approach has not been widely adopted, which may be a consequence of the abstractness of solvation itself and also of the lack of a simple bridge between solvation and other thermodynamic properties. Here, we establish and summarize the relationship between solvation and other properties frequently used in phase equilibrium modeling. An important quantity, called the total solvation free energy, is introduced so that one can easily derive engineering thermodynamic models (such as an equation of state) from solvation models, or vice versa. The equations presented here are of general validity and would be useful for obtaining existing model parameters from solvation calculations and for developing new models stemming from the ideas of molecular solvation.     

Understanding hydrotropism: A chemical engineering perspective

The mechanism of root hydrotropism has been a mystery for many years, due to the complexity of the interactions between the external environment and plants themselves. To gain an engineering perspective, the time‐dependent hydrotropism of a single root has been modeled, initially using a two‐dimensional model. Based on the water and nutrient distribution in rhizosphere as computed with the conservation equations, together with a basic reaction‐kinetics‐type growth model and an intuitive root bending model, it has been found that the root already possesses the property of hydrotropism. For the first time, hydrotropism could be tracked by a process engineering model, which is a new idea based on chemical engineering concept, suggesting an alternative mechanism of hydrotropism. The effects of different initial root widths, lengths, and other growth/transport coefficients on root hydrotropism have then been explored. © 2015 American Institute of Chemical Engineers AIChE J, 62: 1331–1346, 2016     

Mathematical modeling in chemical engineering and biotechnology

This article reviews publications in Russian journals on mathematical modeling in chemical engineering and biotechnology. The major emphasis is on crystallization, mass transfer, and dissolution in chemical engineering processes, as well as steady and unsteady states in biotechnology. Two approaches to modeling in biotechnology are considered: structured and unstructured approaches.     

Cycle detection and characterization in chemical engineering

Nonperiodic cycles occur in times series obtained in many chemical engineering applications. Variations in the cycle characteristics provide valuable information about the system in which the time series was measured. New methods are developed to detect cycles and determine their characteristics such as the cycle time, its regularity, the cycle strength, and the regularity of the cycle amplitude. These methods are thoroughly validated with both mathematically generated and experimental time series. The best detection method for nonperiodic cycles uses either the V statistic or, if it fails, the new, more sensitive, but more complex, P statistic. Cycle characteristics can be used to detect flow regime transitions in multiphase systems such as risers, gas-solid, and gas-liquid-solid fluidized beds using signals from a variety of simple probes.