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第 8 卷第 3 期过程工程学报 Vol.8 No.3 2008 年 6 月 The Chinese Journal of Process Engineering June 2008

Received date: 2008−02−18; Accepted date: 2008−04−28 Biography: YANG You-qi (1935−), male, native of Xiangtan City, Hunan Province, Bachelor, Professor, major in process systems engineering,

E-mail: [email protected].

Microscale and Nanoscale Process Systems Engineering: Challenge and Progress

YANG You-qi (杨友麒)

(China National Chemical Information Center, Beijing 100029, China)

Abstract: This is an overview of the development of process systems engineering (PSE) in a smaller world. Two different spatio−temporal scopes are identified for microscale and nanoscale process systems. The features and challenges for each scale are reviewed, and different methodologies used by them discussed. Comparison of these two new areas with traditional process systems engineering is described. If microscale PSE could be considered as an extension of traditional PSE, nanoscale PSE should be accepted as a new discipline which has looser connection with the extant core of chemical engineering. Since “molecular factories” is the next frontier of processing scale, nanoscale PSE will be the new theory to handle the design, simulation and operation of those active processing systems. Key words: process systems engineering; microchemical engineering; nanotechnology; molecular factory CLC No.: TQ021.8 Document Code: A Article ID: 1009−606X(2008)03−0616−09

1 INTRODUCTION According to Schumpeter's innovation wave theory,

we may now be living in the first half of bio/nano/info wave. We find there a shortage of knowledge in understanding the world of a smaller scale. For instance, in the nanoscale world only since 1981 we have managed to measure the size of an atom cluster on a surface, and only in 1991 we were able to move atoms on a surface. Assembling molecules by physically positioning their component atoms is an issue of the 21st century[1−3]. Now we can say that we are entering an epoch of “molecular processing”. As Hegedus[1] pointed out, there is a new overlap between chemical engineering and chemistry in scales ranging from tens of nanometers to hundreds of micrometers. This new overlap is the focus of research to fill the knowledge vacancy in the small-scale world.

This small-scale world should be divided into two categories according to their spatial and temporal characteristics: microscale process systems and nanoscale process systems. Since there is a 1000-time difference spatially between them, the research objects, methodologies and dominating rules are quite different. The characteristic length of the former systems is 1∼100 µm (microchannel size) and that of the latter systems is about an nm (supramolecular size), the characteristic time scale of the former systems is ms and that of the latter µs. The spatial and temporal scopes of traditional process systems engineering (PSE), microscale PSE and nanoscale PSE are shown in Fig.1.

Fig.1 The different spatio−temporal scopes of process systems engineering (PSE)

The development of fine chemical and pharmaceutical industries has promoted the demand of speedy commercialization of product innovation by shortening the period from laboratory to market. “Making your learning at a small scale and your profits on a large scale” has become the common understanding in the process industries. However, “learning at a small scale” used to mean lab and pilot plants, although now it means microscale and nanoscale experiments. This not only means that in recent research environment, innovation could be accomplished much faster, much cheaper and much better in smaller-scale facilities, but also means that many new process possibilities could only be implemented in microscale facilities[4].

Current production modes are increasingly challenged by decentralization, modularization and

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第 3期 YANG You-qi: Microscale and Nanoscale Process Systems Engineering: Challenge and Progress 617

miniaturization. Process intensification also tends toward this direction. If in 1970∼1980s the whole chemical industry tried reducing cost through enlarging equipment size in order to gain competitive advantage, since the end of last century, a contrary trend has emerged, because the high energy consumption of large plants, heavy pollution to environment, and low efficiency of traditional chemical industry could not meet the requirements of sustainable development. Compared with the fast upgrading of micro-electronic- mechnical systems (MEMS), the contrast is obvious. Miniaturization of chemical lab and plant is becoming a realistic trend in this new century[5].

2 MICROSCALE PROCESS SYSTEMS ENGINEERING

2.1 Features and Advantages of Microscale PSE Since 1980s of the last century, integrated circuit

and MEMS have continued to develop, until in 1989 Ciba Geigy published micro-total-analytical-system (µ-TAS) as a representative microdevice for application in combinatorial chemistry and high throughput screening. In 1995 the first workshop on microsystems technology for chemical and biological microreactors in Germany has been credited for giving birth to a new discipline: microreactor engineering[6]. Since then international conferences on microreactor technology have been held almost every year. At about the same time, Du Pont published the first demonstration microchemical plant to synthesize a number of hazardous chemicals including isocyanates which have storage and shipping limitations[7].

Therefore, integrating the design idea of MEMS and principles of chemical engineering, and transplanting the micro-fabrication technology of integrated circuit and microsensor led to the birth of a new high-technology, microchemical technology. Microchemical technology studies the design, simulation, operation, control and application of microchemical systems within the spatial range of 1∼100 µm and temporal range of 1∼100 ms. Such kind of systems has many features different from traditional chemical systems as follows:

(1) The miniaturization of length scale causes significant effects on transport properties and acting forces, as shown in Table 1[8,9]: ① The specific surface area increases 102∼103 times as the scale of flow channel reduces. The specific surface area of regular flow channel is not more than 1000 m2/m3, but that of microchannel could be as high as 10000∼50000 m2/m3.

② The ratios of viscous force to inertial force and of interfacial force to inertial force in microchannel are several orders of magnitude higher than that in regular equipment, meaning that laminar flow always happens in microchannels and heat conduction with molecular diffusion dominates the transport phenomena. Therefore heat and mass transfer will be significantly intensified; for example, the heat transfer coefficient for micro-heat exchanger could be as large as 25000 W/(m2⋅℃), as compared with that of regular heat exchanger of 200 W/ (m2⋅℃). The mass transfer coefficient for multichannel microreactor could be KLa≈5∼15 s−1, which is two orders of magnitude larger than those for macroscopic reactors, KLa≈0.01∼0.08 s−1 [10]. These characteristics foretell the possibility of high yields of chemical reactions under such microscale extreme conditions. ③ Since inertial force has much less influence in small dimensions, space turbulence is avoided. The high heat and mass transfer rates also allow reactions to be performed under more uniform temperature conditions. All of these make it feasible to fully characterize chemical reaction engineering parameters from sensor data.

Table 1 Scaling effect of transport properties[8] Property nm µm mm m

Length (L) 10−9 10−6 10−3 1 Surface area (L2) 10−18 10−12 10−16 1 Volume (L3) 10−27 10−18 10−9 1 Specific surface area (L−1) 109 106 103 1 Rate (∝L) 10−9 10−6 10−3 1 Inertial force (∝L4) 10−36 10−24 10−12 1 Viscous force (∝L2) 10−18 10−12 10−6 1 Interfacial tension (∝L) 10−9 10−6 10−3 1 Viscous force/inertial force (∝L−2) 1018 1012 106 1 Interfacial tension/inertial force (∝L−3) 1027 1018 109 1

(2) Miniaturization brings significant reduction of sample amount required in tests, much faster and more accurate. Microchemical systems for combinatorial synthesis and screening samples have reduced the detection time from 2∼3 h to 50 s, and enhanced the accuracy to zmol (10−21 mole)[11]. Contemporary DNA detector and “pharmacy-on-a-chip” are good application examples.

(3) Inherent safety and good controllability. Because the characteristic scale of microstructure is smaller than the fire-spread critical diameter and powerful heat transfer capability of microchannels, explosion is restrained. Therefore microreactors could be safely operated in much wider operation range and with better controllability. Even if explosion happened, there would be less serious results because of its small holdup.

618 过程工程学报第 8 卷

(4) Convenience in process scale-up to commercial production of new products. Numbering-up microreactor units used in laboratory would eliminate costly and time-consuming pilot plant experiments, thereby shortening the development time from lab to commercial production. This feature is very important for fine chemical and pharmaceutical industries, because the lab-to-market time is a key performance index of competitiveness. Besides, 50% chemical reactions used in existing fine chemical industry could be changed from batch production into continuous production by using microreactors in order to increase the yield of high value-added products[12−15].

(5) Possibility of implementing distributed production mode in chemical industry. The features of microsystems make modularization of production much easier, thus making it possible distributed production of chemicals right next to consumers. Such distributed point-of-use chemical synthesis of chemicals with less storage and transport limitations not only eliminates potential dangers, but also better utilizes local resources. Such prospect challenges traditional centralized mode of chemical production. In the future, chemical industry may produce single components to be distributed and finally “assembled” locally into products in the manner of electronic and automobile industries[16].

(6) Pursuing new reaction paths. Increased heat conduction out of catalyst suppresses “hot spots” and opens mild reaction conditions typically not accessible in conventional reactors, thus making easier implementation of highly exothermic reactions in microreactors and opening new possibilities for searching environmentally benign product and process[14,16].

2.2 Challenges to PSE Since 1996, research in microchemical systems has

contributed more than 1000 published papers, though very few among them from engineering viewpoint, particularly PSE one. The difference is primarily due to: first, the pioneers in this field are mostly chemists, not chemical engineers; secondly, at this initial stage of microchemical systems, the crucial technology is microreactor fabrication and application rather than general process design; thirdly, commercial production using microstructured devices has just started and not accumulated enough scale-up experience. Therefore this field is full of challenges as follows:

(1) Modeling of microreactor. Microreactor is the nucleus of microchemical systems, and mathematical models of microreactors form the basis for further research of PSE. Microreactors could be single-phase or

multi-phase, catalytic or non-catalytic, isolated or integrated with other unit operations, e.g., heat exchanger, membrane separation, etc. Some critical indices are found in trying to identify the threshold, e.g., Φ=reaction rate/diffusion rate, at which geometric influence on reaction becomes insignificant[8].

(2) Unit operations at microscale are quite different from the regular ones. First, mixing becomes very important when laminar flow and molecular diffusion dominate to make mixing very slow, calling for reduction of the diffusion length, such as the idea of splitting-recombination mixer[17,18]. Secondly, fluid dynamics of microchannels deviates from classical fluid dynamics, for two-phase flow where interfacial tension dominates. Thirdly, heat transfer efficiency in microchannels is higher for ceramic and glass heat exchangers because of reduced axial heat transfer in ceramic and glass heat exchangers as compared with metallic ones[6,19]. Many new unit operations have been created recently[20], which need to be screened for practical applications at the microscale.

(3) Process integration and optimization. One of the most significant characteristics in a microchemical system is its highly compact integration. Gavriilidis et al.[6] pointed out three kinds of integration architecture: vertical, horizontal and hybrid, and platforms to allow integration of all components using “plug-and-play” modules. Those microprocess integrations have so far been made for fabrication concerns, and general theoretical methodology to guide these activities is not given yet. Kirschneck et al.[21] put forward a three-phase design methodology: process stability study, flowsheet optimization study and industrial plant design, as shown in Fig.2. Pfeiffer et al.[22] tried to optimize microscale separation systems by using distributed agents. Chow[23] pointed out many yet unanswered theoretical problems in microchemical systems design. The difficulties in integration and optimization of microchemical processes could be hardly separated from fabrication technology.

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-Parameter scan-Devices screen-Critical parameters

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Fig.2 Process integration and optimization in process scale-up[21]

(4) Scale-up problems for microstructured systems. There are probably three major reasons for the


popularity of microchemical systems. First, microstructures require highly clean flow in order to avoid blockage; secondly, numbering-up is not as easy as imagined, because distribution uniformity needs to be guaranteed; thirdly, it is difficult to persuade enterprise managers to adopt new microstructured facilities to replace existing traditional ones. Generally the only opportunity for using microstructured systems is for new plants. Recent research showed that distribution uniformity was probably not as serious as commonly thought. Delsman et al.[24] proved by theoretical analysis and experiments that the influence of maldistribution on overall reactor conversion rate is relatively small (≤0.5%), while the influences of channel diameter and amount of catalyst coating are more pronounced (3%∼5% lower conversion rate). Rebrov et al.[25] proposed a header consisting of a cone diffuser connected to a thick-walled screen, which improves nonuniformity to less than 0.2%. Tonkovich et al.[26] proposed a scale-up methodology for commercial-scale steam-methane reforming at a capacity of 8 m3/s. They suggested a uniform index Q=(Mmax−Mmin)/Mmax≤20% is acceptable for industrial use. Hasebe et al.[27,28] proposed a six-step design and scale-up methodology using CFD software. An industrial−academic consortium involving 20 famous companies and research institutes was established in the framework of SUSTECH initiative of European Chemical Industry Council (CEFIC), called IMPULSE (integrated multiscale process units with locally structured elements)[29], aiming to develop a methodology for structured multiscale chemical process design.

(5) Development of simulation tools. Complex coupling for developing simulation models of microchemical systems arises from the strong interaction between electrical, mechanical, thermal, microfluidic, transport and chemical phenomena in compactly configured microgeometries. As early as 1990s of the last century, MIT developed the software MEMCAD to analyze MEMS and Lab-on-a-chip, followed by COMSOLab which developed another software, FEMLAB. Recently the most popular simulation tool used for microchemical systems is CFD based on finite element analysis, which is capable of simulating geometric influences on reactions though not of simulating mass and heat balance of whole systems. In order to do so, it is necessary to nest CFD into special flowsheeting software for microchemical systems.

(6) Operation and control of microsystems to insure that the microreactors are compactly integrated with sensors and actuators in order to shorten their

response time. If model predictive control (MPC) is used, the model calculation must be sufficiently fast, e.g., calculation speed is 50∼500 times faster than real time[30,31]. Palusinski et al.[31] pointed out that process control of microchannel systems involving high-frequency signal processing is not suitable using popular digital control techniques and is better using analog circuits. But the latter has been limited by the difficulty in implementing algorithms of high complexity due to the finite accuracy of analog components. So it is desirable to have flexible, programmable systems that allow the functional partitioning of analog and digital circuits to be changed during processing. They put forward a new technology of field-programmable analog arrays which could meet such requirements[31]. Another problem in operating microchannel systems is diagnosis of blocked channels, which could be treated by the method developed by Kano et al.[32] based on data base and models.

3 NANOSCALE PSE 3.1 Nanotechnology and Nanoscale Systems

Nanotechnology, a high-tech developed since the end of last century, is devoted to the understanding, control and manipulation of matter at the level of individual atoms and molecules as well as at the “supramolecular” level involving clusters of molecules. Its goal is to create materials, devices and systems with essentially new properties and functions because of their small structures. The development of this technology serves to fill up mankind's knowledge of many new phenomena and processes at the scale of individual molecules to 100 molecules, that is, 1∼100 nm.

From an engineering viewpoint, Roco[2] identified four generations of nanotechnology products and research since 1996:

First generation (∼2001) dealt with passive nanostructured products, illurtrated by nanostructured coatings, dispersions of nanoparticles and bulk materials, e.g., nanostructured metals, polymers and ceramics.

Second generation (∼2005) consisted of active nanostructured products, illustrated by transistors, amplifiers, targeted drugs and chemicals, actuators and adaptive structures. Molecular tectonics was put forward in this period, aimed at making precise functional supramolecules to build meso-/nano-scale units, such as nanoreactors, separators, molecular tubes, motors, pumps and molecular gates/channels for selective transport of special molecules. Key research included multiscale modeling and simulation, nanobiosensors and devices, and tools for molecular


medicine. Third generation (∼2010) is to start with 3-D

nanosystems and nanosystems engineering, various syntheses and assembling techniques such as bio-assembling and networking at nanoscale and multiscale architectures. Research focus will shift toward supramolecular systems engineering which includes directed multiscale self-assembling, chemico-mechanical processing, and nanoscale electronic-mechanical systems (NEMS), and targeted cell therapy with nanodevices.

Fourth generation (∼2015) will consider heterogeneous molecular nanosystems in which each molecule has a special structure and plays a different role, and each system possesses a unique function. Such systems approach the way that biological systems work in aqueous surrounding with relatively slow information processing. Emerging in this generation are the molecular factories, behavior of complex macromolecular assemblies, nanosystem biology for healthcare and agricultural systems, human-machine interface at the tissue and nervous system level.

With the birth of nanoscale process systems engineering, Stephanopoulos et al.[33] at MIT proposed “nanoscale factories” as the next frontier of processing scale and nanoscale PSE as the new theory to handle the design, simulation and operation of those active processing systems.

3.2 Features and Challenges for Nanoscale PSE Biological cell is a prototypical model of

“supramolecular factory”: the plasma membrane defines the boundaries of the “factory”, allowing for selective flow of molecules in and out of the cell. The cell's organelles, such as nucleus, endoplasmic reticulum, mitchondria, lysosomes, endsomes, etc., represent the “supramolecular unit operations”.

A typical nanoscale processing system is composed of the following components: molecular scaffold, supramolecular unit operations, material transport elements, monitoring and controlling signals. While biologists are exploiting the mechanism of fundamental functions, chemists are synthesizing serial new structured supramolecules which possess the simulated biological functions[34]. Those typical nanoscale processing units are listed as follows:

Scaffolds: (1) Biological molecules (DNA, viruses). (2) Inorganic scaffolds (branched nanocrystals, crossed nanowire grids).

Unit operations: (1) Reactors, variety of configurations (circle, loop, tube) and reaction functions

(including catalyst). (2) Separators, including nanoporous media, membranes, molecular sieves, molecular channels, ionic gates, etc., which have the capability of selectively transporting ions or molecules. (3) Molecular mixer and splitter. (4) Energy formation and dissipation.

Material transporters: (1) Nanotubes, using various driving potentials (chemical/charge distributions along tubes, etc.) to transport ions, molecules or isomers. (2) Molecular motors, pumps and shuttles.

Control elements: (1) Signal carriers, molecular electrical wires, directional “effective” concentrations of surface charges, ions or molecules. (2) Actuators, molecular switches, gates, valves, etc.

The research of molecular tectonics has already managed to use simpler molecules assembling to unit operation supramolecules with the above complex functions. Among those building components there are many simple and familiar molecules, porphyrins, fullerines, multifunctional heterocycles, metal complexes, silsequioxanes, oxyanions, catechols, chalcogenide clusters and multi-hydrogen-bonding molecules[34].

Facing this kind of “molecular factories”, what are the challenges for PSE? Probable problems are the following: (1) The accuracy of scale description in nanoprocessing is quite different from that of traditional PSE; the position precision requires an accuracy of a few Ǻ to nanometers. (2) Using average bulk value to describe the properties is not suitable in nanosystems, because that is based on the assumption of “continuity of the material”. However, this assumption only keeps valid for thickness of liquid layers larger than 10 molecules, while in molecular factory made by supramolecules, it is no longer valid. (3) The principles of design and fabrication are different from those of traditional PSE. The philosophy of design and manufacture for regular systems is a top-down hierarchical approach. But for nanoprocessing, systems can be fabricated with such positioning accuracy that only through guided bottom-up self-organization of molecules and supramolecules can make it possible. (4) The principles of operation and control are different. The control of traditional process systems is based on central control, distributed control or loops−center coordination control, but control of a nanoscale process system primarily relies on self-regulation and secondarily on external control signals. Self-regulation at a process-wide scale can only be achieved through judicious interactions among the supramolecular units


acting as independent agents, since very limited external manipulations are technologically possible to effect on-system operation. (5) The mechanism of nanoprocess systems is essentially the engineering of complex systems because of their self-assembly, self-organization, self-replication and self-regulation. As Ottino[3] has identified, “what is a complex system? Complex systems can be identified by (1) what they do, they display organization without central organizing principle (emergence), and (2) how they may or may not be analyzed, decomposing/analyzing subparts do not necessarily give a clue as to the behavior of the whole.” The tools for study of complex systems are nonlinear dynamics and chaos, statistical physics (including probabilistic approach), agent-based modeling, and networks theory (including small-world network and scale-free network)[35,36]. 3.3 Nanoscale PSE as a Periphery Discipline

As Ottino[3] pointed out in the period 1960s∼1970s, periphery disciplines were developed as expansions of their core: ideas flew from the core to the periphery. However, since 1990s the periphery was only loosely connected to the core, a shift from where tools unified the picture to a stage in which the periphery overpowered the core. Nanoscale PSE could be realized as a cross-discipline, as demonstrated in Fig.3, where one may find the PSE, system biology, molecular tectonics and molecular computer are all fueling the development of nanoscale PSE.

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Fig.3 The feature of nanoscale PSE as a periphery discipline

Molecular tectonics as a new branch of modern chemistry studies how molecules construct those complex molecular networks driven by different functional forces and how supramolecules are generated with specific functions. This discipline has already obtained many interesting research results from porous metal-organic compounds to engineered crystals. It has given the way to design principles that arm the imaginative architect with blueprints for constructing

novel materials across organic and inorganic chemistry[37,38].

System biology is a new discipline to study the relationships between overall functions and constructed components and the new interface between molecular biology and physiology. Nano-PSE is using the research results of system biology to design and manufacture artificial biological systems, such as silicon cells[39−41].

Since Adleman put forward the idea that DNA could be used to construct a generic computer in 1994, the molecular computer was born as a branch of computational life science. There are two ways in the development of the molecular computer: (1) the biological way, exploiting the computational capability of biological molecules and trying to create faster computation speed (massively parallel), smaller size (nanoscale) and more cost effective (energy saving) information processing systems, and (2) the molecular electronics way, trying to design and manufacture digital computers with more precise circuits. This is only miniaturization of the traditional digital computer, the principles remaining the same[42,43].

4 COMPARISION OF MICRO-, NANO- AND TRADITIONAL PSE Comparing the features of micro-, nano- and

traditional PSE systems, Table 2 delineates the big differences between them. We can realize that the principles of microscale PSE are more or less similar to that of traditional PSE, making microscale PSE somewhat an extension of macroscale PSE. However nanoscale PSE is quite different from macroscale PSE in terms of methdologies of design, manufacturing and operation of the systems, having rather loose connections with the core chemical engineering and PSE, as shown in Fig.4.

This kind of multi-scale process systems engineering study is entering the research scope of complex systems, as studied by Li et al.[44,45] and Kwauk[46]. Correlation between different scales, coupling between time and space dependencies and identification of dominant mechanisms are becoming the important steps in studying complex systems. Finding spatio−temporal compromise between dominant mechanisms is crucial in process integration. That also calls for the correlation between spatial and temporal changes in order to understand what differences of extremum features exist between local instantaneous variables and spatio−temporal average variables.


Table 2 Comparison of PSEs in different scales

Macro-process system Microstructured system Nanoscale factories Typical system Chemical plant µTAS (Micro-total analysis system) Biological cell, silicon cell

Scale of manufacturing and topological configuration

Size measured in meters Configuration driven by cost, environmental and safety considerations

Size measured in mm, but positional accuracy could be in µm, configuration driven by effective space utility and process efficiency.

Scale from a few to few hundred nm, positional accuracy in few Ǻ to few nm; Overriding consideration of topological flowsheet is overall-system functionality.

Property of processed material Bulk characterization of processed materials (average over whole or local systems)

As long as the critical size of liquid media is of order 10 molecular layers, the continuum assumption holds. The characterization of supramolecular unit operations, transporters and molecular control structures cannot be based on averaged bulk properties, but on specific atomic and molecular configurations.

Design and fabrication Design approach is top-down, hierarchical approach. Manufacturing is also through top-down, man−machine controlled construction.

Only through a free and/or guided bottom-up self-organization of molecules and supramolecular structures

Operational control structure

Time-constants are from minutes to hours, operating cycle times are from hours to years. Control systems: multivariable centralized control or centralized coordination of local control loops.

Time-constants are from seconds to minutes; operating cycle times are from seconds to minutes. Control Systems: multivariable centralized control or centralized coordination of local control loops.

Time-constants are milliseconds, operating cycle times are seconds, primary control mechanism is self-regulation.

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CoreChem.Eng

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Fig.4 The different relationships between core discipline and new branch discipline [(a) The methodologies and tools of branch disciplines are mostly the same as those of core discipline; (b) The methodologies and tools of branch disciplines only have loose connection with those of core discipline.]

5 CONCLUSIONS (1) One of important development directions of

PSE in new century is exploring the new features of smaller world. In this direction, two different PSE scopes are identified: microscale PSE and nanoscale PSE. Because of their big spatio−temporal difference, the research methodologies and control rules are quite different between these areas.

(2) Due to the scale reduction, microchemical systems gain significant advantages over traditional process systems, and rapid promotion. Although

microchemical systems challenge traditional PSE in terms of fluid dynamics of microreactors and micro-unit operations, process integration and industrial scale-up, but microscale PSE could be considered an extension of traditional PSE.

(3) As “molecular factories” are the frontier of next generation manufacturing, traditional PSE is not valid in this area. Because there are essential differences between molecular factories and traditional chemical plants in terms of position precision, description of physical properties, and principles of design and operation. Nanoscale PSE could be realized as an inter-discipline, where one may find the PSE, system biology, molecular tectonics and molecular computer are all fueling the development of nanoscale PSE. Nanoscale PSE should be accepted as a new discipline which has looser connection with the extant core of chemical engineering.

(4) As both microchemical systems and nanotechnology are rapidly growing and being involved in commercialization, creation of tools for new PSE methodologies is expected to fulfill instant demands in order to theoretically guide research and commercial practice in the smaller world.

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