Local and global process intensification

The present paper aims at proposing a complementary view of process intensification (PI) based on the concepts of local intensification and global intensification. Local intensification is defined here as the classical approach of PI based on the use of techniques and methods for the drastic improvement of the efficiency of a single unit or device. Some examples are given to illustrate that local process intensification presents several limitations when compared to holistic overall process-based intensification, named global intensification. Indeed, when PI focuses on single units (reactors, separators, hybrid separators, etc.), the strong interactions among all units within the process are ignored and the impact of local intensification of a single unit can be very limited, resulting in weak improvement of the whole process. This paper identifies that process intensification is broader than technical improvement of devices or processes and has to consider several drivers such as economics, safety, eco-efficiency and sustainability to fulfill the key objectives in designing new plants and retrofitting existing units.     

Large‐scale sonochemical reactors for process intensification: design and experimental validation

Acoustic cavitation results in substantial enhancement in the rates of various chemical reactions but the existing knowledge about the application of reactors based on acoustic cavitation is limited to very small capacities (of the order of few millilitres). In the present work, an overview of the application of acoustic cavitation for the intensification of chemical reactions has been presented briefly, discussing the causes for the observed enhancement and highlighting some of the typical examples. A novel reactor has been developed operating at a capacity of 7 dm³ and tested with two reactions, ie liberation of iodine from aqueous potassium iodide and degradation of formic acid. The energy efficiency of the reactor has been calculated and compared with the conventional sonochemical reactors. The effect of frequency of irradiation on the percentage conversion of the reactants has been studied. Due to quite low conversions in the case of formic acid degradation, further intensification was attempted using aeration, addition of hydrogen peroxide, and the presence of solid particles (TiO₂). Compared with conventional reactors the novel reactor gives excellent results and it can be said that the future of using acoustic cavitation for process intensification lies in the development of large‐scale multiple frequency multiple transducer reactors. Copyright © 2003 Society of Chemical Industry     

典型过程强化技术在纳米材料制备中的应用进展

纳米材料被誉为21世纪的新材料,广泛应用于化工、电子、国防、陶瓷等领域。传统的纳米材料制备方法面临粒径控制较困难、批次间重复性差,存在放大效应等不足。过程强化技术是化学工程学科的研究前沿和热点方向之一,旨在通过在生产过程中采用新工艺、新设备等手段,实现缩减操作单元、减小设备体积、提高生产能力及能量利用效率的目的,是实现化工过程安全、高效、绿色的重要途径。过程强化技术不仅在制备时间和能源利用效率等方面明显优于常规方法,还可以得到特殊形态和性能的纳米材料。过去二十年中,过程强化技术广泛应用于纳米材料的小试和规模化制备,并取得了良好的经济及社会效益,引起越来越多科学研究者的重视。本工作以超重力、微化工、微波、超声、等离子体技术、离子液体为代表,综述了过程强化技术在纳米材料制备领域中的应用及相关研究的最新进展,结合实例对不同领域进行了概述,分析总结了各领域的优势和特点,讨论了在快速发展的纳米材料制备领域中存在的机遇和挑战,并展望了其未来的应用前景。     

Static mixers: Mechanisms,applications, and characterization methods – A review

Static mixers and multifunctional heat exchangers/reactors (MHE/R) are qualified as efficient receptacles for processes including physical or chemical transformations accompanied by heat transfer due to their high productivity and reduced energy expenditures. The present work reviews recent conceptual and technological innovations in passive static mixers and continuous in-line reactors. Current industrial applications are discussed from a process intensification perspective, focusing on mixing and mass transfer performance. Typical experimental techniques employed to characterize and quantify the mixing process are explored. The work is complemented by a review of mixing fundamentals, knowledge of which allows the development of theoretical models crucial for the analysis of experimental data, like the chemical probe mixing assessment method. Considering the development of continuous flow equipment in numerous processes, advances in this field will certainly be of increasing interest to the scientific and industrial communities.     

Development and analysis of heterogeneous catalytic processes and reactors

A retrospective review and a review of the current state are given for the problem of the development and analysis of heterogeneous catalytic processes and reactors. Advanced approaches to the study of kinetics and the engineering design of catalytic reactions are discussed. The advantages and drawbacks of the main types and structures of industrial catalytic reactors are demonstrated by the examples of present-day catalytic processes and reactors for basic organic and petrochemical synthesis. The operation of several industrial catalytic reactors is analyzed in order to clarify the causes of deterioration of design performance and/or to find ways for the process intensification in operating plants.     

Multifunktionale Reaktoren

In multifunctional reactors chemical and physical unit operations are carried out simultaneously. Traditionally chemical reaction engineering considers mass and heat transfer processes in combination with chemical reactions. However, the term multifunctional reactor points to an extended and more detailed view of process integration. By application of these reactors it is possible to save investment and/or operating costs, to meet environmentally relevant limits or to improve process safety. Mechanical and thermal unit operations are especially good candidates for integration with a chemical reaction step. In this contribution selected multifunctional reactors are presented, which were either adopted from the literature or are the subject of the authors' own research activities.     

Numerische Simulation disperser Gas/Flüssig‐Strömungen in Blasensäulen bei hohen Gasgehalten mit OpenFOAM® Teil 1 – Grundlagen der Modellierung

Various chemical products are synthesized in processes using gas/liquid reactors with bubbly flows. Hence, there is significant interest in a more efficient process design as well as in process intensification with a strong focus on this reactor class. However, the design of industrial gas/liquid reactors requires more detailed information about the flow structures and characteristics of two‐ or multiphase systems. The basic models for two‐fluid model simulations of dispersed gas/liquid flows in bubble columns at high gas fractions are presented..     

Numerical Simulation of Dispersed Gas/Liquid Flows in Bubble Columns at High Phase Fractions using OpenFOAM®. Part I – Modeling Basics

Various chemical products are synthesized in processes using gas/liquid reactors with bubbly flows. Hence, there is a significant interest in a more efficient process design as well as in process intensification with a strong focus on this reactor class. However, the design of industrial gas/liquid reactors requires more detailed information about the flow structures and characteristics of two‐ or multiphase systems. The basic models for two‐fluid model simulations of dispersed gas/liquid flows in bubble columns at high gas fractions are presented.     

多相反应体系的微界面强化简述

加氢、氧化等气液慢反应过程广泛存在于现代过程工业之中,这些反应过程一般受传质速率控制。因此,对这类多相反应体系的传质强化一直是研究热点之一。但总体而言,除外场和微通道（微流控）强化等一类强化反应器外,以往的研究大多集中于界面尺度为毫-厘米级的传统反应器的搅拌与混合方式、气泡分布状态、流体流型、构效关系等方面,而鲜有将研究视角投放到传统以米为直径计量单位的反应器平台上如何构建尺度为微米级的界面体系及其特殊效应方面。探讨了多相反应体系的微界面反应强化理念,并简述了微界面的涵义、微界面反应强化与构效调控方法、微界面反应器的结构与形成原理、微界面体系的微颗粒测试与相界面表征技术、微界面反应强化面临的问题与挑战等,以与本领域同行共同研讨。     

Process intensification aspects for steam methane reforming: An overview

Steam methane reforming (SMR) is the most widely used process in industry for the production of hydrogen, which is considered as the future generation energy carrier. Having been perceived as an important source of H₂, there are abundant incentives for design and development of SMR processes mainly through the consideration of process intensification and multiscale modeling; two areas which are considered as the main focus of the future generation chemical engineering to meet the global energy challenges. This article presents a comprehensive overview of the process integration aspects for SMR, especially the potential for multiscale modeling in this area. The intensification for SMR is achieved by coupling with adsorption and membrane separation technologies, etc., and using the concept of multifunctional reactors and catalysts to overcome the mass transfer, heat transfer, and thermodynamic limitations. In this article, the focus of existing and future research on these emerging areas has been drawn. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Design aspects of sonochemical reactors: Techniques for understanding cavitational activity distribution and effect of operating parameters

Cavitation is a phenomenon having enormous potential for intensification of physical and chemical processing applications such as chemical synthesis, industrial wastewater treatment, cell disruption for release of intracellular enzymes, crystallization, extraction and leaching. However, the dynamic behavior of cavitational activity, especially in sonochemical reactors based on the use of ultrasonic irradiations, creates problems in proposing reliable design and operating strategies. The present work presents an overview of different techniques to understand the cavitational activity distribution in the reactor, highlighting the basic aspects, its applicability and relative merits/demerits. A detailed analysis of the literature has also been made with an aim of explaining the dependency of the cavitational activity on the design of sonochemical reactors and also the operating parameters. Recommendations for optimum operating parameters and design of reactor based on the experimental as well as theoretical analysis have been reported. Some trends in the future reactor designs useful in large scale applications have also been discussed.     

气液等离子体过程强化技术及其在高级氧化过程的应用

气液等离子体过程强化技术是20世纪80年代发展起来的一门新兴交叉学科,在高级氧化过程、液相化学合成和纳米材料制备等领域具有巨大的研究与应用价值。从化学工程的角度理解,气液等离子体过程强化技术的本质是特殊外场作用下的多相传递与反应过程,其中涉及高能电子碰撞、化学活性组分氧化、紫外光解和冲击波等多种物理与化学作用。由于气液等离子体过程强化技术本身的复杂性及多学科交叉性,对其复杂的物理与化学耦合机理还未得到充分认识,同时缺乏对气液等离子体反应器的系统研究及设计指导,从而极大程度地限制了该技术的进一步应用和发展。为全面认识气液等离子体过程强化技术,本文综述了近年来有关气液等离子体过程强化技术的诊断及机理研究进展,并剖析了气液等离子体反应器的设计思路,同时回顾和展望了气液等离子体高级氧化过程的最新研究进展,讨论了气液等离子体过程强化技术的研究方向。     

谈过程强化技术促进化学工业转型升级和可持续发展

化工过程强化是通过采用新装备和新方法,显著提升传递过程速率或反应过程速率的技术。与当今常用的装备和技术相比,可以显著地改进制造和加工过程,大幅度地提高设备产能,降低能耗或废物的产生,是一种更廉价、更可持续发展的技术。本文介绍了化工过程强化的原理、方法与技术特点,阐明了化学工业发展与化工过程强化的内在关系,分析了化工过程强化在生态化工导向大背景下的地位和作用。基于化工过程强化技术对促进发展思路转变、工艺装备技术创新、节能减排降耗和支撑化工可持续发展等方面的作用,论述了化工过程强化技术对促进化学工业转型升级和提升化学工业社会声誉度的重要性。     

过氧化氢绿色合成工艺研究进展

过氧化氢是一种重要的绿色化工产品。由氢气和氧气直接催化合成过氧化氢是一种理想的原子经济性反应,但是该方法的工业化应用面临严峻的技术挑战。本文介绍了近年来氢氧直接合成过氧化氢反应过程相关的活性催化组分Pd、双金属Pd-Au、固体酸类载体、膜反应器和微通道等新型反应器的研究与应用性能;基于过程集成与强化的角度,提出将氢氧直接合成过氧化氢过程与其它特定生产工艺相集成,减少不必要的提浓、运输和稀释等环节,以实现安全、环保的过氧化氢绿色生产和应用。     

Process intensification of synthesis of magnetite using spinning disc reactor

An instantaneous co‐precipitation reaction for the synthesis of magnetite particles has been investigated in conventional mechanically agitated reactor and novel spinning disc reactor (SDR) with an objective of process intensification. Characteristics of the particles have been analysed using Coulter Counter particle analyser. It has been observed that the particle size distribution is more uniform with overall lower power consumption in the SDR as compared to the conventional reactors. With a viewpoint of improving the synthesis process in terms of the obtained conversion levels in the SDR, effect of different operating parameters viz. rotational speed, diameter and type of the disc, flow rate of the reactants and the operating temperature on the synthesis process has also been investigated. It has been observed that the flow rate of the reactants as well as disc characteristics have a significant influence on the extent of conversion. Overall, it has been established that the SDR gives excellent particle size distribution characteristics as compared to the conventional approaches and hence results in process improvement/intensification for magnetite synthesis process at comparatively lower energy inputs.     

The effect of operating and design parameter on bubble column performance: The LOPROX case study

It is known that the performances of multi-phase reactors depend on the operating parameters (the temperature and the pressure of the system), the phase properties, and the design parameters (the aspect ratio (AR), the bubble column diameter, and the gas sparger design). Hence, the precise design and the correct operation of multi-phase reactors depends on the understanding and prediction of the fluid dynamics parameters. This paper contributes to the existing discussion on the effect of operating and design parameter on multi-phase reactors and, in particular, it considers an industrial process (e.g., the LOPROX (low pressure oxidation) case study, which is typical example of two-phase bubble columns). Based on a previously-validated set of correlations, the influence of operating and design parameter on system performances is studied and critically analyzed. First, we studied the effects of the design parameter on the liquid–gas interfacial area, by keeping constant the fluid physical–chemical properties as well as the operating conditions; subsequently, we discussed for a fixed system design, the influence of the liquid phase properties and the operating pressure. In conclusion, this paper is intended to provide guidelines for the design and scale-up of multi-phase reactors.     

化工技术在生物冶金过程强化中的研究进展

随着高品位矿物的消耗枯竭，生产成本高、环境污染严重的传统火法冶炼技术已不能适应我国经济社会可持续发展的需要。以生物堆浸和生物槽浸为代表的生物冶金技术具有操作简单、成本低廉、环境友好等特点，可用于低品位、复杂矿物的处理，目前已广泛应用于铜、金等有价金属的回收利用。但是，生物冶金过程中相对较慢的反应速度是限制其应用范围进一步扩大的主要原因。生物冶金技术的基本过程与化工过程紧密相关，化工技术的发展在历史上曾极大地促进生物冶金技术的推广应用，通过化工技术强化生物冶金过程仍是未来生物冶金研究的主要方向之一。因此，本工作综述了近年来与生物冶金有关的化工过程研究进展，主要从工业应用角度分析了生物堆浸和生物槽浸过程的影响因素，以期帮助研究者更好地了解相关领域的发展现状，正确把握研究方向。     

Process intensification in vapor–liquid mass transfer: The state-of-the-art

The concept of process intensification(PI) has absorbed diverse definitions and stays true to the mission—"do more with less", which is an approach purposed by chemical engineers to solve the global energy environment problems. To date, the focus of PI has been on processes mainly involving vapor/liquid systems. Based on the fundamental principles of vapor–liquid mass transfer process like distillation and absorption, there are three strategies to intensify interphase mass transfer: enhancing the overall driving force, improving the mass transfer coefficient and enlarging the vapor–liquid interfacial area. More specifically, this article herein provides an overview of various technologies to strengthen the vapor–liquid mass transfer, including application of external fields, addition of third substances, micro-chemical technology and usage of solid foam, with the objective to contribute to the future developments and potential applications of PI in scientific research and industrial sectors.     

On the controllability and run-away possibility of a totally free piston,pulsed compression reactor

The pulsed compression reactor promises to be a compact, economical and energy efficient alternative to conventional chemical reactors. While its design and operation is similar to that of a free piston internal combustion engine, it does not benefit from any controllability through the load. Experimental data and simulation results are presented in this article. They form the basis for an approach that describes the functioning, controllability and run-away possibility of the pulsed compression reactor. The approach demonstrates that two operating points can be identified: a stable operating point and an unstable operating point. For any process performed in the pulsed compression reactor, there will either be no operating point, in which case it will not be able to sustain this process in the reactor, there will be only a stable operating point, in which case the process will automatically converge to this point once initiated, or there will be both a stable and an unstable operating point, in which case the process can be sustained at the stable operating point, but not at or beyond the unstable one.