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In Honor of Gerhart Eigenberger Gerhart Eigenberger turns 65 this summer, and it is a great privilege and pleasure for us to write the preface to this special issue honoring the pioneering professional achievements of this outstanding scientist. The papers included here were contributed by some of Gerhart’s friends and colleagues, in recognition of his remarkable career and of his contributions to many different areas of chemical engineering. Gerhart Eigenberger was born on August 14, 1939, in Prague, Czech Republic, as the only child of a family having its roots in the former Austro-Hungarian Empire. Chemistry was present in the life of Gerhart actually from the very moment of his birth. His father was a professor of organic chemistry at the (German) University of Prague, while his mother was his research assistant. Sadly, his father did not survive the end of the war. After the war Gerhart grew up in Wiesbaden, Germany, located on the banks of the river Rhine. Here he met his later wife and lifetime companion Doris. They have two sons. After military service, Gerhart enrolled in 1960 in Mechanical Engineering at the prestigious Technische Hochschule Darmstadt (presently Darmstadt University of Technology, Darmstadt, Germany). He chose to major in control engineering and in chemical technology. At that time Darmstadt had a very strong control engineering group, headed by Winfried Oppelt, and an
equally strong Institute of Chemical Technology, led by Professor Karl Schoenemann. In fact, Schoenemann’s institute can be considered a cradle of modern chemical engineering in Germany. Numerous outstanding German scholars studied there, including Hanns Hofmann, Ulrich Hoffmann, Karl Hans Simmrock, Gerhard Emig, and Ernst-Dieter Gilles. It was Ernst-Dieter Gilles with whom Gerhart Eigenberger spent the initial 10 years of his scientific career as one of his first assistants. When Gilles moved to Stuttgart to build up the Institut fu¨r Systemdynamik und Regelungstechnik (ISR; Institute of System Dynamics and Control), Eigenberger joined him. His work at ISR was initially concerned with the modeling and control of tubular reactors for exothermic reactions. Because ISR at that time did not have sufficient experimental facilities, Eigenberger’s laboratory-scale reactor was hosted by the Institut fu¨r Technische Chemie (Professor Dialer) in Bo¨blinger Strasse. Fifteen years later he came back to his roots when this laboratory became part of his Institut fu¨r Chemische Verfahrenstechnik. Toward the end of his Ph.D. work, Gerhart started collaboration with the group of Professor Ewald Wicke in Mu¨nster, Germany, investigating dynamic phenomena in fixed-bed reactors, such as thermal instability, wrong-way behavior, and kinetic instability. Gerhart’s first publications concern the dynamics and multiplicity
10.1021/ie040121y CCC: $27.50 © 2004 American Chemical Society Published on Web 06/05/2004
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of steady states in catalytic fixed-bed reactors.1,2 They were part of the efforts in Gilles’ group to systematically model, analyze, and control the dynamics of chemical reaction systems. It was obvious at that time that two different effects were responsible for steady-state multiplicity in fixed-bed reactors with exothermic reactions: backward conduction of heat along the main flow coordinate and single-pellet instability. Eigenberger showed that backward conduction of heat should be incorporated in the solid-phase energy balance to avoid an unlimited number of steady states in the two-phase model. Later he extended his work to point at the influence of heat conduction in the reactor wall.3 In 1973 Gerhart finished his Ph.D. thesis on the simulation and control of tubular reactors under the supervision of Ernst-Dieter Gilles and shortly afterward, being granted a scholarship by the German Science Foundation, he moved to Northwestern University in Evanston, Chicago, IL, where he joined for 1 year the group of John Butt. Under Butt’s supervision and in collaboration with another famous expert in heterogeneous catalysis, Bob Burwell, Eigenberger participated in investigations on catalyst poisoning and its influence on fixed-bed reactor dynamics.4 There he also developed one of the first efficient computer codes with automatic space step control in order to simulate wrong-way behavior and fixed-bed reactor transients with steep moving fronts.5 It was also in Evanston where Gerhart attended his first ISCRE symposium (ISCRE-3, 1974), which for him was, as he recalls it today, his first meeting with all of the “big guys” of the chemical reaction engineering arena. After returning to Stuttgart, he completed his qualifying thesis (“Habilitation”), again under the supervision of Gilles and again in collaboration with the group of Wicke. Kinetic instability, in particular during catalytic CO oxidation, was the main topic of this thesis.6 The challenge was to develop an isothermal kinetic model based upon reasonable surface reaction steps that was able to both produce multiple steady states and relaxation oscillations, as observed in the experiments of Wicke’s group.7-9 The outstanding quality of this work was recognized by DECHEMA, who in 1977 awarded him the DECHEMA prize of the Max Buchner Research Foundation. After finishing his thesis, Gerhart Eigenberger decided to gain industrial experience and moved to BASF, where he joined the department of “Technical Informatics” within Chemical Engineering Research (Technische Entwicklung). His boss, Theo Ankel, whom he succeeded later on in this position, was a renowned expert on automatic control of chemical processes and plants. At BASF, Gerhart spent 10 years carrying out research projects in modeling, design, and control of chemical reactors (fixed-bed reactors in particular). Problems investigated included catalyst dilution for control of hot spots, heat-transfer and temperature control in multitubular reactors, and energy-balance-based control of batch and semibatch reactors. Acrolein and acrylic acid syntheses, dehydrogenation of ethylbenzene to styrene, and an ethylene oxide process were among the processes he studied with his team.10 Willy Ruppel and Hans Schuler, both former Ph.D. students of Gilles, were among his prominent team partners at BASF.11,12 He summarized later much of his industrial experience in the chapter on fixed-bed reactors, written for Ullmann’s Encyclopedia of Industrial Chemistry.13 During his
BASF years, Gerhart kept a teaching appointment with the University of Stuttgart, lecturing every second semester in Gilles’ institute on the modeling and simulation of chemical reactors. A further chapter in Gerhart’s career opened in 1986 when he succeeded Heinz Blenke as full professor and director of the Institut fu¨r Chemische Verfahrenstechnik (Chemical Process Engineering Laboratory, ICVT) in Stuttgart. In this traditional and well-established institute with a broad spectrum of research areas, it was a challenge to extend the knowledge into new fields of chemical engineering. Eigenberger structured the research activities at ICVT in three working areas: chemical reaction engineering, physicochemical processes, and chemical power generation. The basis for treating this broad spectrum of applications has been provided by common methods organized in three groups: apparatus and plant design headed by the vice director of ICVT, Clemens Merten, numerical methods and computer applications headed by Gheorghe Sorescu, and experimental methods for kinetic measurements of conversion and exchange processes headed initially by Gerd Gaiser and later taken over by Clemens Merten. Eigenberger explored how mathematical modeling and numerical simulation combined with specific and detailed experiments could provide a sound understanding of the problems and processes at hand. Building on this understanding and engineering intuition, his group was able to improve existing processes and to develop new processes in several areas of chemical engineering. A new focus of Gerhart’s early work at ICVT was set on efficient processes for air and water pollution control. He also introduced a rigorous chemical engineering approach to the analysis of automotive exhaust purification systems. He finally became one of the promoters of the development of the fuel cell technology for smallscale and mobile applications. In his original field on catalytic fixed-bed processes, Eigenberger pursued the simulation of multitubular reactors14 and unravelled the old issue of the interdependence between the flow distribution and radial heat transfer in randomly packed tubes through simultaneous computation of the flow, concentration, and temperature fields.15 The theoretical analysis was complemented by sophisticated experiments for identifying model parameters and evaluating the simulation results.16,17 Being aware of the inherent limitations of randomly packed beds, Gerhart shifted the focus to novel concepts in order to overcome these restrictions. Regular catalyst structures with efficient wall heat transfer were one of his focal points,18 which led to the development of the folded sheet reactor. This reactor integrates the advantages of a microstructured wall reactor regarding temperature control with the ability to insert and replace catalysts as in packed-bed reactors.19 It is also characteristic of the spirit at ICVT that feasibility studies based upon simulations were not considered a sufficient proof of concept. Supported and often guided by ICVT’s ingenious design engineer, Gerhard Friedrich, detailed solutions in the apparatus design were developed and implemented in bench-scale prototypes. A successful recent example is the design of a compact, fully heat integrated, 10 kW methanol reformer for hydrogen production, incorporating feed evaporation, steam reforming, water gas shift, and anode off-gas combustion.20
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Starting from his early cooperation with David Agar and Willy Ruppel at BASF, Eigenberger has become attracted by multifunctional, thermally integrated reactors, operating in a forced transient mode and their potential for process intensification. The reverse-flow reactor concept became an evergreen in his research activities. His early work with Ulrich Nieken focused on the reactor control under strongly fluctuating operating conditions typical for air purification applications.21-24 This resulted in a novel, simplified picture for the complex interactions in reverse-flow reactors, building on the analogy of reverse-flow operation under fast cycling with countercurrent reactor operation.25 This equivalence proved to highly facilitate rigorous parametric analysis and optimization of reverse-flow reactors and to provide an elegant shortcut method for assessing new ideas.26 On the basis of this fundamental knowledge, the application of countercurrent and reverse-flow reactors was extended to the coupling of endothermic and exothermic reactions.27-30 In its most recent design, reverse-flow operation may provide a thermally efficient process for strongly endothermic reactions such as methane steam reforming.31 During a long-lasting cooperation with Volkswagen, Gerhart’s group developed a sequence of detailed models of the three-way catalyst,32,33 which are now capable of predicting the emissions of vehicles during test cycles with sufficient accuracy.34 Because diesel and lean-burn engines tend to dominate the market, Gerhart directed research at ICVT also to NOx reduction in the presence of excess oxygen and to the issue of soot filter regeneration. The field of gas-liquid bubble-column and loop reactors had been the focal point of Eigenberger’s predecessor at ICVT, Heinz Blenke. For quite a while, the detailed mathematical modeling of such reactors seemed out of reach. With the support of BASF, an applied mathematician from Moscov, Alexander Sokolichin, entered Eigenberger’s group as a post doc. This initiated a fruitful sequence of pioneering works on computational fluid dynamics (CFD) modeling and simulation of bubble-column flow dynamics.35-37 Starting from scratch, he managed to tackle previously unsolvable problems. Meanwhile, his modeling and numerical concepts are widely accepted and implemented in stateof-the-art CFD packages.38 The success of the theoretical approach has been supported by the parallel development of novel experimental setups and implementation of optical techniques for flow visualization.39,40 Also in this field the activities were driven by the attempt not to resolve the complete details of the considered systems but rather to identify and to exploit the crucial structural and dynamic flow properties for a comprehensive reactor analysis. It resulted in an iterative method for modeling the macroscopic dynamic behavior of gasliquid reactors based on adaptive time and space averaging of the bubble dynamics and hydrodynamics.41,42 This work was part of the European collaborative research project ADMIRE, aimed at the buildup of expertise in the field of gas-liquid reactors. Wellrecognized additional results were experimental studies on reaction-enhanced mass transfer in bubble columns43 and studies on gas coalescence and redispersion in bubble-column reactors under industrial conditions.44 Fixed-bed adsorption became another point of interest in Eigenberger’s institute.45,46 His early work focused on the environmentally benign recovery of solvents from
exhaust air. A heat-integrated temperature-swing adsorption process employing a multistep regeneration mode has been developed in cooperation with Kraftanlagen-Heidelberg.47 A novel multifunctional adsorber reactor has solved the problem of adsorbent deactivation in purification of exhaust streams contaminated with styrene, which undergoes polymerization and coking.48 Regeneration is accomplished there through combustion of solid deposits. This process has also been used as a model system for theoretical analysis of gas-solid reaction fronts. A milestone was Gerhart’s cooperation with his colleagues Fritz and Weitkamp aiming at the use of monolithic packings made from zeolites in adsorption processes.49,50 The novel materials have initially been used in the separation of xylene isomers employing a combined temperature- and pressuredriven regeneration. In the following, Eigenberger shifted the focus to gas separation processes via pressure-swing adsorption, particularly splitting or oxygen enrichment of air. The design of these processes was traditionally the subject of empirical methods. A thermodynamically consistent model library has been developed at ICVT that eliminated widespread heuristics originating from the confusion of modeling and numerical implementation.51 The validity of empirical design rules has been assessed, and control strategies have been developed based on systematic simulations.52 Recently, the focus has been extended to the production of pure hydrogen from reforming processes and to the design of compact pressure-swing adsorption units based upon new-type adsorbent-polymer compound mass-transfer devices and their efficient operation.53 Besides the research activities, Gerhart consistently pursued the transfer of the novel concepts to industrial practice; e.g., in cooperation with Daimler-Benz, he implemented a combined temperature-vacuum-swing adsorption to recycle amines from foundry exhaust streams.54,55 Eigenberger took up the research on membrane processes that was initiated by his predecessor. He developed this field in close cooperation with Heiner Strathmann in the late 1980s and early 1990s. The focus has been set on electromembrane processes using monoand bipolar membranes.56,57 This work has been supported by the Willy-Hager-Foundation and by various other public and private funds. Novel solutions have been proposed for improved efficiency based on appropriate structuring of the stack and process stream distribution. Initially, electrodialytic regeneration of ionexchange resins58 and electrodialytic purification of lactic acid in fermentation processes were the major topics.59 Continuous electrodeionization (CEDI) has been for ultrapure water production.60 Recent work in this field focuses on the application of bipolar membranes in nonaqueous systems.61 The link between all of these topics is a rigorous, thermodynamically consistent modeling. Clear separation of equilibrium and kinetic effects allows for parameter identification with simple and accurate experiments and opens a wide prediction horizon to numerical simulation. Besides basic research, Eigenberger devoted many efforts toward implementation of the new ideas. Several pilot setups have been built and tested successfully under industrial conditions. The methods developed for the electrochemical processes paved the way for a detailed analysis and simulation of polymer-electrolyte-membrane fuel cells
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(PEMFC) in close cooperation with the German Aerospace Research Centre (DLR) in Stuttgart.62-65 Gerhart succeeded in establishing at the ICVT a group of polymer chemists headed by Jochen Kerres. Kerres’ group gained international reputation for the development of novel and highly efficient arylic polymer-based membranes for hydrogen (PEMFC) and direct methanol fuel cells (DMFC).66-70 Membrane fuel cell systems including membrane development, stack design, heatintegrated reformer concepts, and gas purification are presently a main focal point at ICVT.71,72 It is Gerhart Eigenberger’s merit of having gathered this broad spectrum of physicochemical processes, recognizing analogies, and utilizing synergies among them in order to create a detailed, model-based understanding upon which optimal solutions can be generated. However, his major contribution to the scientific community is his systematic approach, balancing necessary detailing with sufficient generality. His own statement of “our approach is based on the close interplay between detailed modelling and specific experiments” summarizes his scientific policy. Following this guideline, he contributed novel, powerful methods to numerical simulation and experimental analysis of chemical reaction engineering systems. He systemized modeling and simulation of multiphase systems, with a moving fluid and a fixed solid phase (fixed-bed or membrane processes) by a “piecewise 1D approach”.73 Using this approach, it is possible to generate hierarchical model libraries of complex systems, e.g., NOx storage catalysts, EME assemblies in fuel cells, or electrodialysis cells. Moreover, this provides the basis for a modular simulation approach based on physically motivated domain decomposition. The numerical expertise at ICVT has benefited from the long-lasting cooperation with numerical mathematicians at the Konrad-Zuse-Center Berlin. The adaptive algorithm PDEX has been adopted for simulation of 1D distributed dynamic models, and a front end has been developed for chemical engineering applications.73 The PDEXPACK software package became the standard tool for the solution of demanding fixed-bed process models.74-76 Eigenberger contributed his vast experience in modeling and simulation to the cooperative research project “Computer-Based Modelling and Simulation of Chemical Engineering Processes”. This project headed by Gilles joined the expertise of a group of faculty colleagues with similar vision and drive. The results of this collaborative research were awarded the Research Prize of Baden-Wu¨rttemberg in 1992. In the context of this cooperation, Eigenberger’s group developed the graphic system IGS for online visualization of dynamic simulation results. IGS and the interactive simulation environment based on it are extremely useful not only for the figurative illustration of complex dynamic phenomena but also for support of the development of numerical models. Software made at ICVT has been licensed to more than 20 partners from academia and industry. The same ambition regarding scientific excellence and practical relevance has driven Eigenberger’s efforts in the field of experimental methods. Experiments are considered as a complement to numerical methods in the context of an integrated methodical approach. Following this idea, experiments are not designed to resemble conventional technical processes but primarily to yield quantitative information about elementary
processes under well-defined conditions. Few examples from Gerhart’s work illustrate the significance of this approach: The flat-bed reactor has been developed for kinetic measurements in heterogeneous catalytic gas-phase reactions.78 The conditions in the reactor approximate the idealized model assumptions while ensuring isothermal conditions on the catalyst. The flat-bed reactor has been used for several complex reaction systems, e.g., the three-way catalyst, the NOx storage catalyst, the maleic anhydride synthesis, or the reforming of hydrocarbons. A capillary evaporator has been invented at ICVT for generating small vapor streams for laboratoryscale experiments: an apparently simple task but one without a satisfying solution available before. Meanwhile, the capillary evaporator belongs to the standard equipment not only at the ICVT but also in the laboratories of many partners in academia and industry. A highlight of Gerhart’s experimental work is the development of a fermentation process calorimeter with a resolution of 20 mW/L that has been commercialized by industrial partners.79 The fact that the apparatus design, the sensors, and the control have been developed in-house is indicative of the expertise available in his laboratory. Gerhart’s achievements were recognized and honored with prestigious awards and appointments. In 2000 he received from DECHEMA-GVC the Gerhard Damko¨hler Medal for his achievements in Chemical Reaction Engineering. In 2002 he was elected to the Heidelberg Academy of Sciences. Naturally, Gerhart was and is very active outside the ICVT. For many years he represented Germany in the Working Party on Chemical Reaction Engineering of the European Federation of Chemical Engineering, later becoming its Secretary and eventually chairing it from 1995 to 1998. In 1995 he was elected to the Senate of the German Research Foundation (DFG) and in 1999 became one of its Vice Presidents. Among his responsibilities are the Beijing Sino-German Center of Science Promotion (in close collaboration with the Natural Science Foundation of China). One major incentive of his engagement at the DFG has been his concern for the quality of teaching. He is author of a memorandum on the reformation of the education in technically oriented universities in Germany, aiming at optimal implementation of the Bologna declaration. The prospective of chemical engineering was also the topic of a symposium organized by Gerhart on the occasion of the 40th anniversary of the ICVT. The status of teaching as his principal mission manifests in the appreciable amount of time he routinely devotes even today with all his experience to prepare his classes. Besides the indisputable quality of his courses, the students appreciate his extraordinary sociability: one never sees him leaving a lecture room in a hurry. He is always approachable to the students for discussing their problems and their worries. He is actively interested in getting direct feedback about the conditions related with their studies. An integral part of his engagement in teaching is the supervision of Ph.D. students. Covering this huge spectrum of research activities, he provides young scientists a job opportunity and a prospective for their professional career. The Ph.D. projects at ICVT include well-balanced experimental and theoretical tasks in order to complement the scientific skills of the students. Gerhart involves co-
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workers in teaching and in various research projects, but he also encourages any autonomous initiative. During his time as ICVT director, the economy and the job market passed through ups and downs and the conditions of sponsoring academic research changed tremendously. Nevertheless, Eigenberger committed himself to ensuring employment to all co-workers until they got settled elsewhere. At the same time he initiated new projects and attracted young, competent students in order to ensure the continuity in the research activities of his group. Being often surprised by sudden changes of the external conditions, he never confronted his employees with these troubles. He managed to balance steadiness and progress with caution and widesightedness but also with personal engagement to exhaustion. This hidden part of his work, driven by his deep humanity, deserves at least the same recognition as his scientific achievements. Gerhart represents the model of a top professional for all those who have had the privilege to interact with him. The respect he has gained worldwide confirms his principles and his approach; his achievements provide a bright example that success of a venture depends decisively on the dedication of the acting persons. The above details will probably challenge his modesty. However, it is not our intention to sing him praises. The aim of this brief survey on his career is to light up his motivation and his vision. Gerhart Eigenberger will soon leave his Chair at Bo¨blinger Strasse and will pass on the leadership of ICVT to his successor. However, he will definitely not leave chemical engineering, the discipline he loves and to which he has devoted so many years of his outstanding career. He will surely remain involved in some exciting research projects and will be supporting his successor in building the future of ICVT on his legacy. We are absolutely sure we will keep seeing him active for many years to come. Acknowledgment Numerous friends and colleagues of Gerhart Eigenberger contributed to this special issue. Many others, whose names have not appeared in the Table of Contents, also join us in wishing him all the best in this new chapter of his life: Lieber Gerhard, zu Deinem 65. Geburtstag danken wir Dir herzlichst fu¨r Deine zahlreichen und wichtigen wissenschaftlichen Beitra¨ge und Ideen. Wir wu¨nschen Dir und Deiner Frau Doris noch viele, viele glu¨ckliche Jahre. Literature Cited (1) Eigenberger, G. Dynamic behavior of the catalytic fixedbed reactor in the region of multiple steady states. I. Influence of heat conduction in two phase models. Chem. Eng. Sci. 1972, 27 (11), 1909-1915. (2) Eigenberger, G. Dynamic behavior of the catalytic fixedbed reactor in the region of multiple steady states. II. Influence of the boundary conditions in the catalyst phase. Chem. Eng. Sci. 1972, 27 (11), 1917-1924. (3) Eigenberger, G. Influence of the wall on the dynamic behaviour of homogeneous tubular reactors with highly exothermic reaction. Adv. Chem. Ser. 1974, 133, 477-488. (4) Weng, H. S.; Eigenberger, G.; Butt, J. B. Catalyst poisoning and fixed bed reactor dynamics. Chem. Eng. Sci. 1975, 30 (11), 1341-1351. (5) Eigenberger, G.; Butt, J. B. A modified Crank-Nicolson technique with non equidistant space steps. Chem. Eng. Sci. 1976, 31, 681-691.
(6) Eigenberger, G. Mechanismen und Auswirkungen kinetischer Instabilita¨ten bei heterogen-katalytischen Reaktionen. Habilitationsschrift, Universita¨t Stuttgart, Stuttgart, Germany, 1977. (7) Eigenberger, G. Kinetic instabilities in catalytic reactionss a modeling approach. Chemical Reaction Engineering, Proceedings of the 4th International Symposium; DECHEMA: Frankfurt/Main, 1976; pp 290-299. (8) Eigenberger, G. Kinetic instabilities in heterogeneously catalyzed reactions. I. Rate multiplicity with Langmuir-type kinetics. Chem. Eng. Sci. 1978, 33 (9), 1255-1261. (9) Eigenberger, G. Kinetic instabilities in heterogeneously catalyzed reactions. II. Oscillatory instabilities with Langmuirtype kinetics. Chem. Eng. Sci. 1978, 33 (9), 1263-1268. (10) Eigenberger, G. Practical problems in the modeling of chemical reactions in fixed bed reactors. Chem. Eng. Process. 1984, 18 (1), 55-65. (11) Eigenberger, G.; Schuler, H. Reaktorstabilita¨t und sichere Reaktionsfu¨hrung. Chem. Ing. Tech. 1986, 58, 655-665. Eigenberger, G.; Schuler, H. Reactor stability and safer reaction engineering. Int. Chem. Eng. 1989, 29 (1), 12-25. (12) Eigenberger, G.; Ruppel, W. Problems of Mathematical Modelling of Industrial Fixed-bed Reactors. Ger. Chem. Eng. 1986, 9, 74-83. (13) Eigenberger, G. Fixed Bed Reactors. Ullmann’s Encyclopedia of Industrial Chemistry; VCH-Verlag: Weinheim, Germany, 1992; Vol. B4, pp 199-238. (14) Stankiewicz, A.; Eigenberger, G. Dynamic modeling of multitubular catalytic reactors. Chem. Eng. Technol. 1991, 14 (6), 414-420. (15) Daszkowski, T.; Eigenberger, G. A reevaluation of fluid flow, heat transfer and chemical reaction in catalyst filled tubes. Chem. Eng. Sci. 1992, 47 (9-11), 2245-2250. (16) Bey, O.; Eigenberger, G. Fluid flow through catalyst filled tubes. Chem. Eng. Sci. 1997, 52 (8), 1365-1376. (17) Bey, O.; Eigenberger, G. Gas flow and heat transfer through catalyst filled tubes. Int. J. Therm. Sci. 2001, 40, 152164. (18) Eigenberger, G.; Kottke, V.; Daszkowski, Th.; Gaiser, G.; Kern, H.-J. Regelma¨ ssige Katalysatorformko¨ rper fu¨ r technische Synthesen; VDI-Fortschrittsberichte Reihe 15; VDI-Verlag: Du¨sseldorf, Germany, 1991; Nr. 112, ISBN 3-18-141215-5. (19) Friedrich, G.; Opferkuch, F.; Gaiser, G.; Kolios, G.; Eigenberger, G. Compact fixed-bed reactor for catalytic reactions with integral heat exchange. Eur. Patent EP 0885653B1, prior to 1997. (20) Morillo, A.; Merten, C.; Eigenberger, G.; Hermann, I.; Lemken, D. Compact folded reactor concept for autothermal steam reforming with integrated evaporation and shift stage. Chem. Ing. Tech. 2003, 75, 68-72. (21) Eigenberger, G.; Nieken, U. Catalytic Combustion with Periodic Flow Reversal. Chem. Eng. Sci. 1988, 43 (8), 2109-2115. (22) Eigenberger, G.; Nieken, U. Katalytische Abluftreinigung: Verfahrenstechnische Aufgaben und Lo¨sungen. Chem. Ing. Tech. 1991, 63 (8), 781-791. Eigenberger, G.; Nieken, U. Catalytic cleaning of polluted air: reaction engineering problems and new solutions. Int. Chem. Eng. 1994, 34 (1), 4-16. (23) Nieken, U.; Kolios, G.; Eigenberger, G. Fixed-bed reactors with periodic flow reversal: experimental results for catalytic combustion. Catal. Today 1994, 20, 335-350. (24) Nieken, U.; Kolios, G.; Eigenberger, G. Control of the ignited steady state in autothermal fixed-bed reactors for catalytic combustion. Chem. Eng. Sci. 1995, 49 (24B), 5507-5518. (25) Nieken, U.; Kolios, G.; Eigenberger, G. Limiting Cases and Approximate Solutions for Fixed-bed Reactors with Periodic Flow Reversal. AIChE J. 1995, 1915-1925. (26) Kolios, G.; Frauhammer, J.; Eigenberger, G. Autothermal fixed-bed reactor concepts. Chem. Eng. Sci. 2000, 55, 5945-5967. (27) Frauhammer, J.; Eigenberger, G.; von Hippel, L.; Arntz, D. A new reactor concept for endothermic high-temperature reactions. Chem. Eng. Sci. 1999, 54, 3661-3670. (28) Kolios, G.; Eigenberger, G. Styrene synthesis in a reverseflow reactor. Chem. Eng. Sci. 1999, 54, 2637-2646. (29) Kolios, G.; Frauhammer, J.; Eigenberger, G. A simplified procedure fort he optimal design of autothermal reactors for endothermic high-temperature reactions. Chem. Eng. Sci. 2001, 56, 351-357.
4474 Ind. Eng. Chem. Res., Vol. 43, No. 16, 2004 (30) Kolios, G.; Frauhammer, J.; Eigenberger, G. Efficient reactor concepts for coupling of endothermic and exothermic reactions. Chem. Eng. Sci. 2002, 57, 1505-1510. (31) Glo¨ckler, B.; Kolios, G.; Eigenberger, G. Analysis of a novel reverse-flow reactor concept for autothermal methane steam reforming. Chem. Eng. Sci. 2003, 58, 593-601. (32) Kirchner, T.; Eigenberger, G. Optimization of the cold-start behaviour of automotive catalysts using an electrically heated precatalyst. Chem. Eng. Sci. 1991, 51 (10), 2409-2418. (33) Kirchner, T.; Donnerstag, A.; Ko¨nig, A.; Eigenberger, G. Influence of catalyst deactivation on automotive emissions using different cold-start concepts. Surf. Sci. Catal. 1998, 116, 125-136. (34) Brinkmeier, C.; Eigenberger, G.; Bu¨chner, S.; Donnerstag, A. Transient Emissions of a SULEV Catalytic Converter System. Dynamic Solution vs Dynamometer Measurements, 2003 SAE World Congress, Detroit, MI, Mar 3-6, 2003; SAE Technical Paper Series 2003. (35) Sokolichin, A.; Eigenberger, G. Gas-liquid flow in bubble columns and loop reactors. Part I. Detailed modeling and numerical simulation. Chem. Eng. Sci. 1995, 49 (24B), 5735-5746. (36) Sokolichin, A.; Eigenberger, G.; Lapin, A.; Lu¨bbert, A. Dynamic Numerical Simulation of Gas-Liquid Two-Phase Flows: Euler-Euler versus Euler-Lagrange. Chem. Eng, Sci. 1997, 52 (4), 611-626. (37) Sokolichin, A.; Eigenberger, G. Applicability of the standard k- turbulence model to the dynamic simulation of bubble columns: Part I. Detailed numerical simulations. Chem. Eng. Sci. 1999, 54, 2273-2284. (38) Sokolichin, A.; Eigenberger, G.; Lapin, A. Simulation of Buoyancy Driven Bubbly Flow: Established Simplifications and Open Questions, Journal Review. AIChE J. 2004, 50, 24-45. (39) Becker, S.; Sokolichin, A.; Eigenberger, G. Gas-liquid flow in bubble columns and loop reactors. Part II. Comparison of detailed experiments and flow simulations. Chem. Eng. Sci. 1995, 49 (24B), 5747-5762. (40) Borchers, O.; Busch, C.; Sokolichin, A.; Eigenberger, G. Applicability of the standard k-e turbulence model to the dynamic simulation of bubble columns. Part II: Comparison of detailed experiments and flow simulations. Chem. Eng. Sci. 1999, 54, 5927-5935. (41) Bauer, M.; Eigenberger, G. A concept for multi-scale modelling of bubble columns and loop reactors. Chem. Eng. Sci. 1999, 54, 5109-5117. (42) Bauer, M.; Eigenberger, G. Multiscale modeling of hydrodynamics, mass transfer and reaction in bubble column reactors. Chem. Eng. Sci. 2001, 56 (3), 1067-1074. (43) Fleischer, C.; Becker, S.; Eigenberger, G. Transient hydrodynamics, mass transfer, and reaction in bubble columns: CO2 absorption into NaOH solutions. Chem. Eng. Res. Des. 1995, 73 (A6), 649-653. (44) Scha¨fer, R.; Merten, C.; Eigenberger, G. Bubble size distributions in a bubble column reactor under industrial conditions. Exp. Therm. Fluid Sci. 2002, 26 (6 and 7), 595-604. (45) Salden, A.; Eigenberger, G. Technical Adsorption of Gases. In Handbook of Porous Solids; Schu¨th, F., Sing, K. S. W., Weitkamp, J., Eds.; Wiley-VCH: New York, 2002; Vol. 4, pp 22232280. (46) Salden, A.; Eigenberger, G. Environmental Protection. In Handbook of Porous Solids; Schu¨th, F., Sing, K. S. W., Weitkamp, J., Eds.; Wiley-VCH: New York, 2002; Vol. 4, pp 2700-2718. (47) Konrad, G.; Eigenberger, G. Rotary adsorbers for waste gas purification and solvent recovery. Chem. Ing. Tech. 1994, 66 (3), 321-331. (48) Salden, A.; Eigenberger, G. Multifunctional adsorber/ reactor concept for waste-air purification. Chem. Eng. Sci. 2001, 56, 1605-1611. (49) Trefzger, C.; Boger, T.; Fritz, H.-G.; Eigenberger, G. Compounding and Forming of Zeolite Structures. European Meeting of the Polymer Processing Society, Stuttgart, Germany, Sept 1995. (50) Boger, T.; Fritz, M.; Ascher, R.; Ernst, S.; Weitkamp, J.; Eigenberger, G. Selective separation of p- and m-xylene over zeolitic adsorbents in the gas phase. Chem. Ing. Tech. 1997, 69 (4), 475-480. (51) Unger, J.; Eigenberger, G.; Straub, M.; Hofmann, U. Temperature effects in PSA/VSA separation processes: Modelling, simulation and technical significance. ECCE-1/ICheaP-3, Florence, Italy, 1997; AIDIC: Milano, Italy, 1997; Vol. 4, pp 27852788.
(52) Bitzer, M.; Lengerer, W.; Stegmaier, M.; Eigenberger, G.; Zeitz, M. Process Control of a 2-Bed Pressure Swing Adsorption Plant and Laboratory Experiment CHISA 2002. 15th International Congress of Chemical and Process Engineering, Prague, Czech Republic, Aug 25-29, 2002; Paper No. 833. (53) Gorbach, A.; Stegmaier, M.; Eigenberger, G. Einsatz neuartiger Adsorber-Polymer-Monolithe in effizienten, kompakten Druckwechseladsorptionsprozessen 18, Stuttgarter KunststoffKolloquium, Mar 19-20, 2003; 1/P4. (54) Boger, T.; Salden, A.; Eigenberger, G. A combined vacuum and temperature swing adsorption process for the recovery of amine from foundry air. Chem. Eng. Process. 1997, 36, 231-241 (55) Boger, T.; Salden, A.; Eigenberger, G. Ru¨ckgewinnnung von Aminen durch Adsorption bei der Kernherstellung nach dem Coldbox-Verfahren unter Produktionsbedingungen. ABAG, Nov 1997. (56) Kuppinger, F.-F.; Neubrand, W.; Rapp, H.-J.; Eigenberger, G. Electro-membrane processesspart 1: Fundamentals and modelling. Chem. Ing. Tech. 1995, 67 (4), 441-448. (57) Kuppinger, F.-F.; Neubrand, W.; Rapp, H.-J.; Eigenberger, G. Electro-membrane processesspart 2: Application examples. Chem. Ing. Tech. 1995, 67 (6), 731-739. (58) Johann, J.; Eigenberger, G. Electrodialytic regeneration of ion-exchange resins. Chem. Ing. Tech. 1993, 65 (1), 75-78. (59) Kuppinger, F.-F.; Busch, C.; Eigenberger, G. Direct electrodialysis of fermentation broth with periodic removal of fouling layers. DECHEMA Biotechnology Conferences, Karlsruhe, Germany, 1992; VCH Verlagsgesellschaft: Weinheim, Germany; Vol. 5, Part B, pp 671-674. (60) Thate, S.; Eigenberger, G. Analysis of electrochemical deionization for ultra-pure water production. Vom Wasser 2003, 101, 243-248. (61) Sarfert, F.; Strathmann, H.; Eigenberger, G. Characterization and Modelling of Bipolar Membranes in Aqueous and NonAqueous Solution Systems. International Congress on Membrane Processes (ICOM), Toulouse, France, 2002. (62) Neubrand, W.; Eigenberger, G.; Wo¨hr, M.; Bolwin, K. Membrane Transport Phenomena in a Polymer-Electrolyte-FuelCell.Hydrogen 96, 11. World Hydrogen Energy Conference, Stuttgart, Germany, 1996; Pergamon Press: Oxford, England; pp 18811885. (63) Wo¨hr, M.; Bolwin, K.; Schnurnberger, W.; Fischer, M.; Neubrand, W.; Eigenberger, G. Dynamic modelling and simulation of a polymer membrane fuel cell including mass transport limitations. Int. J. Hydrogen Energy 1998, 23 (3), 213-218. (64) Siebke, A.; Schnurnberger, W.; Meier, F.; Eigenberger, G. Investigation of the Limiting Processes of a DMFC by Mathematical Modeling. Fuel Cells 2003, 3 (1 and 2), 37-47. (65) Meier, F.; Eigenberger, G. Transport parameters for the modelling of water transport in ionomer membranes for PEM-fuel cells. Electrochim. Acta 2004, 49 (11), 1731-1742. (66) Kerres, J.; Ullrich, A.; Meier, F.; Ha¨ring, Th. Synthesis and characterization of novel acid-base polymer blends for application in membrane fuel cells. Solid State Ionics 1999, 125, 243-249. (67) Kerres, J.; Ullrich, A.; Ha¨ring, Th.; Baldauf, M.; Gebhardt, U.; Preidel, W. Preparation, characterization and fuel cell application of new acid-base blend membranes. J. New Mater. Electrochem. Syst. 2000, 3, 129-239. (68) Kerres, J.; Zhang, W.; Jo¨rissen, L.; Gogel, V. Neuartige kovalent vernetzte kationenleitende Blendmembranen fu¨r DMF. GDCh Monograph. 2001, 23, 121-128. (69) Kerres, J. Development of Ionomer Membranes for Fuel Cells. J. Membr. Sci. 2001, 185, 3-27. (70) Meier, F.; Kerres, J.; Eigenberger, G. Characterization of polyaryl-blend-membranes for DMFC applications. J. New Mater. Electrochem. Syst. 2002, 5 (2), 91-96. (71) Acosta, M.; Merten, C.; Eigenberger, G. Modelling the multiphase flow in the cathode diffusion layer of H2-PEM-fuel cells. Chem. Ing. Tech. 2003, 75, 1038-1039. (72) Springmann, St.; Eigenberger, G. Simulation studies on autothermal reforming of gasoline for hydrogen production. Chem. Ing. Tech. 2002, 74, 1454-1458. (73) Dieterich, E. E.; Eigenberger, G. The ModuSim concept for modular modeling and simulation in Chemical Engineering. Comput. Chem. Eng. 1997, 21 (Suppl.), 805-809.
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Andrzej Stankiewicz* DSM Research, P.O. Box 18, 6160 MD Geleen, The Netherlands, and Delft University of Technology, Delft, The Netherlands
Grigorios Kolios Inistitut fu¨ r Chemische Verfahrenstechnik, University of Stuttgart, Stuttgart, Germany IE040121Y
