Chemical Engineering & Technology

Cover image for Chemical Engineering & Technology

May, 2004

Volume 27, Issue 5

Pages 459–588

    1. A New Era for Chemical Apparatus Engineering? (pages 469–479)

      E. Weiß, S. Praus, J. Rudolph, A. Lietzmann and T. Mense

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200406136

      In the near future, chemical apparatus engineering will have to focus on two main pillars: highly qualified standard and innovative products. The latter, in particular, must be developed in close interaction with chemical engineering in order to put the hardware required for new technologies and process strategies on the market. This article names the important fields of current general technical progress, showing that the thrust is directed toward an elevated level of product quality that can be achieved through apparatus engineering.

    2. More Efficient Plant Design by Modularization? (pages 481–484)

      B. Kampczyk, B. Hicking and H. Schmidt-Traub

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200403203

      The software CAPD which was developed at the University of Dortmund, provides the possibility to quickly display a plant layout though its generation does not contain all the plant details. Through the utilization of a realistic placeholder for any equipment the plant layout can be optimized.

    3. Design of Complex Distillation Columns by Overall-Cost Optimization (pages 484–490)

      S. Wenzel and H.-J. Röhm

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200403205

      Compared with the conventional configuration, complex distillation columns make for a marked reduction of the energy requirements of multi-component rectification systems. Whereas the control problems have, on the whole, been resolved, the ability to find the process-technological optimum of a complex distillation system within a short space of time is still difficult. The aim of this paper is to reduce the time required for finding the optimum design with the aid of commercial standard software.

    4. Utilization of a Two-phase Reactor with Pre-saturator for Multiphase Reactions (pages 490–495)

      B. Battsengel, L. Datsevich, A. Jess, C. Münnich, S. Peter and T. Turek

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200403199

      The two-phase reactor with pre-saturator was investigated for the hydrogenation of 1-octene and the hydrogenation of an adipic hexanediole-oligoester. For low concentrations of the liquid reactant the reactor is a suitable system. For high concentrations a liquid recycle is necessary and although the residence time is higher the recycling might have a positive influence on the external mass transfer.

    5. Process Concepts for the Transition Metal Catalyzed Syntheses of Formic Acid and Dimethylformamide Based on Carbon Dioxide (pages 495–501)

      A. Behr, P. Ebbinghaus and F. Naendrup

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200403221

      In recent years, carbon dioxide has attracted increasing attention as raw material for chemical syntheses. The chemically inert carbon dioxide can be activated by homogeneous transition metal complex catalysts. This permits a number of various syntheses which, however, are only profitable if the catalyst separation and recycling can be carried out completely and simply. The development of process concepts for the syntheses of formic acid and dimethylformamide by the hydrogenation of carbon dioxide are presented here.

    6. Investigations on the Regeneration Intensity of Different Back-Pulse Systems for Surface Filters of Rigid Filter Media (pages 502–505)

      S. Heidenreich, W. Haag, R. Mai, H. Leibold and H. Seifert

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200403239

      In order to improve the cleaning of rigid filter media, a new cleaning method was developed. The patented CPP (coupled pressure pulse) cleaning method is based on the principle that the cleaning system is directly coupled to the clean gas side of the filter elements. The newly developed CPP cleaning process is directly compared with a specific conventional jet-pulse system and the efficiency and the advantages of the new method are demonstrated. It is impressively shown that with the CPP process, an excellent cleaning performance can be achieved.

    7. Experiment and Mathematical Modeling of Solid Formation at Spray Drying (pages 505–510)

      P. Seydel, A. Sengespeick, J. Blömer and J. Bertling

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200403218

      The process of solid formation during spray drying has been described many times in the literature, however, a detailed mathematical description of the time-dependent process concerning the structure of the particles as a function of substance and process parameters is still not available. In the present work, a time-dependent and local modeling of the mass and energy transport processes during solid formation inside the droplet was carried out. The model was validated against reproducible experiments performed in a vertical pipe with single drop generation.

    8. Micronization of Organic Substances by Supercritical Fluid Processes (pages 510–514)

      H. Kröber and U. Teipel

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200403195

      RESS and PCA are two complementary processes to produce particles in the submicronic range. In the RESS process it was found that coagulation processes have a stronger influence on the particle size than supersaturation. Droplet formation, as well as the precipitation in the droplets influences the particle size in the PCA process. Which of the two mechanisms dominates depends on the process parameters and material properties.

    9. Integration of Open Absorption Cycles for Combined Heat Recovery and Dehumidification into Technological Systems (pages 514–518)

      P. Bittrich and D. Hebecker

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200403163

      The discrepancy between quality and quantity of heat is the main problem for heat recovery from gases with high relative humidity. The integration of open absorption cycles into the apparatus results in an increased heat recovery temperature and higher dehumidification of the flue gas. The application of high temperature condensing boiler technology (HT-CBT) is demonstrated in a biomass gasification plant with subsequent use of the gasification gas in a CHP engine.

    10. Mixing and Crystallization Kinetics in Gas-liquid Reactive Crystallization (pages 519–528)

      P.-C. Chen, C.C. Chen, M.H. Fun, O. Y Liao, J.J. Jiang, Y.S. Wang and C.S. Chen

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200401933

      A pH-stat MSMPR crystallizer was effectively used to explore the influences of mixing on crystallization kinetics of barium carbonate crystals in gas-liquid reactive crystallization systems. The mixing parameters were stirrer speed, feed concentration, gas-flow rate, pH of solution, addition rate of NaOH and mean residence time. The feed concentration and the stirrer speed were the significant factors affecting the crystallization kinetics.

    11. Stability Behavior of Liquid Jets under Gravity (pages 529–536)

      S. Nonnenmacher and M. Piesche

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200400049

      The influence of gravity on the stability behavior of falling liquid strands without external excitation was investigated. To this end, a mathematic-physical model was developed for the analysis of the stability behavior of liquid strands in the range of low to higher viscosity, the main emphasis being on gravity. The characteristics of the model are discussed and, finally, the stability criterion is derived for the quantitative determination of the point of disintegration.

    12. Studies on the Hydrodynamics of Chaotic Bubbling in a Gas-Liquid Bubble Column with a Single Nozzle (pages 537–547)

      M. Liu and Z. Hu

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200401935

      The nonlinear bubbling hydrodynamics in a gas-liquid bubble column with a single nozzle was studied. In order to prove that bubbling under certain conditions is chaotic, a series of analyses were undertaken on the time series of pressure fluctuations at different gas flow rates measured from a pressure transducer probe placed in the liquid close to the nozzle. The analysis methods include time domain, power spectrum, phase plot, Kolmogorov entropy and correlation dimension.

    13. A Kinetic Model of Degradation of Phenol in Water by Direct Contact of Gas Nonpulsed Corona Discharge (pages 548–552)

      N. Sano, J. Fujikawa, D. Yamamoto, T. Kanki and A. Toyoda

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200401804

      Reaction byproducts from degradation of aqueous phenol by contact of gas d.c. corona discharge with treated water were analyzed by liquid chromatography. According to the retention time, three byproducts, pyrocatechol, hydroquinone, 1,4-benzoquinone, were identified. Also, acetic acid was detected by gas chromatography as a final relatively stable byproduct. A simple reaction model in which relevant elementary reactions are assumed to be first order is proposed to correlate the practical behavior of degradation processes.

    14. Development of a Dosing Concept for Minute Flow Rates (pages 553–558)

      F. Kießlich, P.M. Prechtl, H. Gerhard, M.A. Liauw, N. Popovska and G. Emig

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200400039

      Automatic regulation and control techniques play an important role for the safe operation of any chemical plant from lab scale up to production plant scale. In the present study a system for simultaneous dosage and pressure control of gaseous and vaporized compounds is realized for pressures ranging from 10–2 to 1000 mbar and flow rates in the range of 5 · 10–4 to 50 NmL/min, thus in the domain of μL/min.

    15. Barium Sulfate Crystallization Kinetics in the Used Quenching Salts Treatment Process (pages 559–568)

      A. Matynia, K. Piotrowski, J. Koralewska and B. Wierzbowska

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200401878

      Research results on barium sulfate crystallization in the process of barium ion precipitation by means of the addition of crystalline ammonium sulfate are presented. The influence of the concentration of barium, sodium, potassium and calcium chlorides in the feeding solution as well as the process temperature on the barium sulfate crystallization kinetics were investigated. The process temperature influences the mean particle size.

    16. Simulation of an Acid-Based Starch Converter (pages 569–577)

      A. Iranshahi, H.R. Hakimelahi, R. Sotudeh-Gharebagh and N. Mostoufi

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200401937

      Converting starch to glucose is a very complicated process, and there is still a lack of detailed understanding of the physicochemical phenomena involved in the converter. A mathematical model is proposed to simulate a starch converter. The model integrates converter hydrodynamics and reaction expressions necessary to model the conversion phenomena and can be used to predict the performance of industrial converters at a wide range of operating conditions.

    17. Residence Time Distribution in Granulation Drums on the Example of Industrial Carbon Black (pages 578–582)

      M. Katzer, S. Pirl, S. Esser, J. Kopietz, T. Rieckmann, J. Behnisch and C.-J. Klasen

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200400029

      The present work describes systematic investigations into dry granulation of industrial carbon black with special regard to the residence time characteristics, using a continuously operated semitechnical bead-forming drum. A novel experimental method and a model for the determination of residence time distribution of carbon black in the bead-forming drum have been developed and very good agreement of model and experiment has been demonstrated.

    18. Hydrate Formation during Pressure Release of Wet CO2,View-Cell Observations (pages 583–588)

      A. Ullrich and R. Eggers

      Version of Record online: 3 MAY 2004 | DOI: 10.1002/ceat.200401932

      The blocking risk of pipelines by hydrate crystals in processing step was evaluated. Two topics were investigated: (I) hydrate formation during pressure release and isochore cooling and (II) the influence of a contact surface on hydrate formation. The investigated materials were steel, glass, and polytetrafluoroethylene (PTFE).The results of the experiments suggest that the major criterion for hydrate formation during pressure release is the degree of supersaturation.