MODELING OF A TRICKLE-BED REACTOR: THE HYDROGENATION OF 2-BUTANONE ON A RUTHENIUM CATALYST. Author(s): Germain, A.; Crine, M.; Marchot, P.; L'Homme, G. A. Author Affiliation: Univ de Liege, Belg Source: ACS Symp Ser Int Symp on Chem React Eng, 5th Mar 13-15 1978 n 65 1978 Houston, TX, USA Am Chem Soc Washington, DC p 411-424 Publication Year: 1978 Abstract: The prediction of the performances of a trickle-bed reactor is possible knowing only the intrinsic rate equation, if a good description of the topological liquid distribution is available. This one can be obtained using the percolation theory and resolving the local forces balances at the gas-liquid and liquid-solid interfaces. For the hydrogenation of 2-butanone, the authors could obtain calculated values of the conversion in satisfactory agreement with the experiments, provide that they take into account all the possible mass transfer processes between all the different types of bed areas. So for the first time the description of the liquid distribution in a trickle-bed catalytic reactor is sufficiently detailed to allow the quantitative prediction of the performances of such a reactor using a volatile liquid reactant. 21 Refs. EI Order Number: 79070000877 Subjects: CHEMICAL EQUIPMENT; CHEMICAL REACTION - Hydrogenation; CATALYSTS; RUTHENIUM AND ALLOYS ;TRICKLE-BED REACTOR Identifiers: TRICKLE-BED REACTOR Classification Codes: 547Effectiveness Factor of Partially Wetted Catalyst Particles: Evaluation and Application to the Modeling of Trickle Bed Reactors Author(s): Lemcoff, N.O. Cukierman, A.L.; Martinez, O.M. Author Affiliation: Ciudad Univ, Buenos Aires, Argent Source: Catal Rev Sci Eng v 30 n 3 1988 p 393-456 ISSN: 0360-2451 CODEN: CRSEC9 Publication Year: 1988 Abstract: The literature has been reviewed on the subject of evaluation and application of the effectiveness factor of catalyst particles in trickle bed reactor design. Numerical solutions have been presented for different catalyst particle geometries and, in most cases, for simple reaction kinetics. Also, several approximate equations have been derived that make the evaluation of the effectiveness factor much easier. Ramachandran and Smith's approximation for gas limiting reactant systems and Dudukovic's definition of Thiele modulus for a liquid reactant system have been proven to be important contributions. Although significant progress has been found in this area, there are still several aspects which remain to be thoroughly analyzed. The applications covered include catalyses of oxidation of ethyl alcohol ad sulfur dioxide, hydrogenation of methylstyrene, and hydrodesulfurization of heavy oils. EI Order Number: Catalysts--Applications; Chemical Equipment--Reactors; Ethanol--Oxidation; Styrene--Hydrogenation; Sulfur Dioxide--Oxidation; Petroleum Refining ;Effectiveness Factor; Trickle Bed Reactor; Methylstyrene; Ethyl Alcohol; Heavy Oils; Mass Transfer Identifiers: Effectiveness Factor; Trickle Bed Reactor; Methylstyrene; Ethyl Alcohol; Heavy Oils; Mass Transfer

Classification Codes: 803 Document Type: JA Treatment: AT 2 ISCRE 9: NINTH INTERNATIONAL SYMPOSIUM ON CHEMICAL REACTION ENGINEERING. VOLUME 1 - CONTRIBUTED PAPERS. Source: Chemical Engineering Science ISCRE 9: Ninth International Symposium on Chemical Reaction Engineering. Volume 1 - Contributed Papers. v 41 n 4 1986 Philadelphia, PA, USA p 607-1135 ISSN: 0009-2509 CODEN: CESCAC Publication Year: 1986 Abstract: This conference contains 65 papers reporting recent advances in chemical reaction engineering. The papers are grouped as follows: applications to biological and solid state processes, mass transport in reactors, fixed bed reactors, fluidized bed reactors, gas-solid-liquid reaction systems, transients in reactor and reaction systems, industrial reaction modeling, polymerization and deploymerization, and parametric sensitivity and multiplicity. EI Order Number: 87040064701 CHEMICAL EQUIPMENT--Reactions; CATALYSTS; MASS TRANSFER; POLYMERIZATION; MATHEMATICAL MODELS; CHEMICAL REACTIONS ;FLUIDIZED BED REACTORS; REACTOR MODELING; POLYMERIZATION REACTORS; TRICKLE-BED REACTORS; EIREV Identifiers: FLUIDIZED BED REACTORS; REACTOR MODELING; POLYMERIZATION REACTORS; TRICKLE-BED REACTORS; EIREV Classification Codes: 802 Document Type: CP 3 MODELING OF TRICKLE BED REACTORS AT HIGH TEMPERATURES AND PRESSURES WITH VOLATILE FEEDS. Author(s): Collins, George M. Hess, Richard K.; Hook, Bruce D.; Akgerman, Aydin Author Affiliation: Texas A&M Univ, Kinetics, Catalysis & Reaction Engineering Lab, College Station, TX, USA Source: Annu Meet Am Inst Chem Eng 1984 Annual Meeting - American Institute of Chemical Engineers. 1984 San Francisco, CA, USA Sponsored by: AIChE, New York, NY, USA AIChE New York, NY, USA 31p Paper: 108B ISSN: 0196-7282 CODEN: AMAEDX Publication Year: 1984 Abstract: The purpose of this study was to develop a model to predict the behavior of trickle beds when the liquid feed is volatile. The model developed is compared with a non-volatile liquid phase model employing the same kinetics. In the model it is assumed that the reactor is operating in plug flow and that there is no significant wall flow, the catalyst bed is completely wetted, the mass transfer effects are negligible, the feed is volatile, and that the reaction takes place on the wetted catalyst in the liquid phase. It is intended to apply this model to hydrotreating processes which take place at high temperatures and pressures with partial vaporization of the feed. 40 Refs. EI Order Number: 85040053530 CHEMICAL EQUIPMENT--Reactors; CATALYSTS; CHEMICAL REACTIONS - Hydrogenation;

CHEMICAL ENGINEERING - Mathematical Models; FLOW OF FLUIDS - Packed Beds; LIQUIDS - Chemical Reactions ;TRICKLE BEDS; PLUG FLOW; WALL FLOW; HYDROTREATING; VOLATILE LIQUID FEEDS Identifiers: TRICKLE BEDS; PLUG FLOW; WALL FLOW; HYDROTREATING; VOLATILE LIQUID FEEDS Classification Codes: 802 Document Type: CA 4 ADVANCES IN TRICKLE-BED REACTOR MODELING. Author(s): Crine, Michel L'Homme, Guy A. Author Affiliation: Univ de Liege, Groupe de Chimie Appliquee et de Genie Chimique, Liege, Belg Source: Recent Adv in the Eng Anal of Chem React Syst 1984 John Wiley & Sons New York, NY, USA p 430-461 Publication Year: 1984 Abstract: Various attempts in modeling heat and mass transport processes are reviewed in this paper. These models are characterized by a homogeneous representation of the fluid flows wherein the gas and liquid flow rates are assumed to be independent of the position in the packing. The paper shows how the main concepts of percolation theory may lead to a phenomenological description of the fluid flow hydrodynamics and, in turn, to the modeling of various transport processes such as the dynamic liquid holdup, the catalyst irrigation rate, the axial dispersion and the radial flow spreading in the liquid phase. These models are compared with experimental results and empirical correlations reported in the literature. (Edited author abstract) 54 Refs. EI Order Number: 85120175747 CHEMICAL EQUIPMENT--Reactors; CHEMICAL REACTIONS - Mathematical Models; FLOW OF FLUIDS; HEAT TRANSFER - Mathematical Models; MASS TRANSFER - Mathematical Models ;TRICKLE-BED REACTOR; RESIDENCE TIME DISTRIBUTION; PERCOLATION PROCESS Identifiers: TRICKLE-BED REACTOR; RESIDENCE TIME DISTRIBUTION; PERCOLATION PROCESS Classification Codes: 802 Document Type: MC Treatment: NT 5 IMMOBILIZED CELL REACTOR-SEPARATOR: EFFECTS OF PRESSURE AND GAS FLOW ON REACTOR PERFORMANCE. Author(s): Dale, M. C. Okos, M. R.; Wankat, P. C. Author Affiliation: Purdue Univ, West Lafayette, Indiana, USA Source: Amer Inst Chem Eng Natl Eng Natl Meet American Institute of Chemical Engineers 1983 Summer National Meeting (Preprints). 1983 Denver, CO, USA Sponsored by: AIChE, New York, NY, USA AIChE New York, NY, USA 26p Paper: N 77D CODEN: ACENC9 Publication Year: 1983 Subjects: BIOCHEMICAL ENGINEERING; ;WHEY LACTOSE FERMENTATION; BUBBLE COLUMN; TRICKLE COLUMN; REACTOR MODELING; COLUMN PERFORMANCE; SPONGE PACKED COLUMN Identifiers: WHEY LACTOSE FERMENTATION; BUBBLE COLUMN; TRICKLE COLUMN; REACTOR MODELING; COLUMN PERFORMANCE; SPONGE PACKED COLUMN Classification Codes: 461

Document Type: CARecord 1 Mathematical modeling of the process of oxidation of SO$-2$/ in a fixed trickle bed of catalyst Author(s): Stegasov, A.N.; Kirillov, V.A. Corporate Source: Inst Kataliza SO RAN, Novosibirsk, Russia Source: Teoreticheskie Osnovy Khimicheskoi Tekhnologii v 27 n 4 Jul-Aug 1993 p 393-397 CODEN: TOKTA8 Publication Year: 1993 Abstract: The mathematical model is proposed for calculation of the process of oxidation of sulfur dioxide in a fixed catalyst bed under continuous and pulsed feeds of the liquid phase. The model is verified using the results of experimental-data processing. In Russian 13 Refs EI Order Number: 94011170299 Subjects: Mass transfer; Differential equations; Hydrodynamics; Mathematical models; Oxidation; Chemical reactors Identifiers: Trickle-bed reactors; Balance equations; Liquid phase; Gaseous phase; Numerical experiments Classification Codes: 631.2 Document Type: JA Treatment: TX1 Effectiveness Factor of Partially Wetted Catalyst Particles: Evaluation and Application to the Modeling of Trickle Bed Reactors Author(s): Lemcoff, N.O. Cukierman, A.L.; Martinez, O.M. Author Affiliation: Ciudad Univ, Buenos Aires, Argent Source: Catal Rev Sci Eng v 30 n 3 1988 p 393-456 ISSN: 0360-2451 CODEN: CRSEC9 Publication Year: 1988 Abstract: The literature has been reviewed on the subject of evaluation and application of the effectiveness factor of catalyst particles in trickle bed reactor design. Numerical solutions have been presented for different catalyst particle geometries and, in most cases, for simple reaction kinetics. Also, several approximate equations have been derived that make the evaluation of the effectiveness factor much easier. Ramachandran and Smith's approximation for gas limiting reactant systems and Dudukovic's definition of Thiele modulus for a liquid reactant system have been proven to be important contributions. Although significant progress has been found in this area, there are still several aspects which remain to be thoroughly analyzed. The applications covered include catalyses of oxidation of ethyl alcohol ad sulfur dioxide, hydrogenation of methylstyrene, and hydrodesulfurization of heavy oils. EI Order Number: Catalysts--Applications; Chemical Equipment--Reactors; Ethanol--Oxidation; Styrene--Hydrogenation; Sulfur Dioxide--Oxidation; Petroleum Refining ;Effectiveness Factor; Trickle Bed Reactor; Methylstyrene; Ethyl Alcohol; Heavy Oils; Mass Transfer Identifiers: Effectiveness Factor; Trickle Bed Reactor; Methylstyrene; Ethyl Alcohol; Heavy Oils; Mass Transfer Classification Codes: 803 Document Type: JA Treatment: AT 2 RECENT ADVANCES IN THE ANALYSIS AND DESIGN OF TRICKLE-BED REACTORS. Author(s): Ramachandran, P. A. Dudukovic, M. P.; Mills, P. L.

Author Affiliation: Washington Univ, St. Louis, MO, USA Source: Sadhana v 10 n pt 1-2 Apr 1987 p 269-298 ISSN: 0256-2499 CODEN: SAPSER Publication Year: 1987 Abstract: This paper summarizes some progress in our understanding of trickle-bed reactors. The particular topics discussed in this review are the basic hydrodynamics, flow regime transition, pressure drop and holdup calculations, use of tracers, modelling of partial wetting effects, reactor design of and catalyst testing in trickle beds. The rapid advances made in these areas are critically examined and some problems which need further investigation are outlined. (Author abstract) 72 Refs. EI Order Number: 88010000352 Subjects: CHEMICAL EQUIPMENT; HYDRODYNAMICS; CATALYSTS ;TRICKLE-BED REACTORS; MULTIPHASE REACTORS Identifiers: TRICKLE-BED REACTORS; MULTIPHASE REACTORS Classification Codes: 802 Document Type: JA Treatment: X 3 LIQUID DISPERSION IN TRICKLE-BED REACTORS WITH GAS-LIQUID COCURRENT DOWNFLOW. Author(s): Chu, C. F. Ng, K. M. Author Affiliation: Univ of Massachusetts, Amherst, MA, USA Source: Amer Inst Chem Eng Natl Eng Natl Meet American Institute of Chemical Engineers 1986 Annual Meeting. 1986 Miami Beach, FL, USA Sponsored by: AIChE, New York, NY, USA AIChE New York, NY, USA 10p Paper: 33E CODEN: ACENC9 Publication Year: 1986 Abstract: The flow pattern can deviate form ideal plug flow in both trickling and pulsing flows. The liquid dispersion in those flow regimes are investigated separately, as the mechanisms causing the deviation of flow pattern from plug flow are different. In trickling flow, the dispersion of the liquid phase occurs in the flow path which is determined with computer-generated packed column. Dispersion in pulsing flow is studied with a combination of the method of characteristics and analysis of liquid dispersion in the liquid slug and gas pulse. The axial dispersion coefficients are then determined based on Monte Carlo simulation. Finally, liquid dispersion in trickle beds containing porous packings is also discussed. (Author abstract) 16 Refs. EI Order Number: 87060096922 FLUID DYNAMICS--Mathematical Models; CHEMICAL EQUIPMENT - Reactors; FLOW OF FLUIDS - Pulsatile Flow; MATHEMATICAL STATISTICS - Monte Carlo Methods ;LIQUID DISPERSION; TRICKLE-BED REACTORS; TRICKLING FLOW; AXIAL DISPERSION COEFFICIENTS; POROUS PACKINGS Identifiers: LIQUID DISPERSION; TRICKLE-BED REACTORS; TRICKLING FLOW; AXIAL DISPERSION COEFFICIENTS; POROUS PACKINGS Classification Codes: 631 Document Type: CA 4 MODELING THE HYDROTREATING REACTIONS OF A HEAVY RESIDUAL OIL IN A PILOT TRICKLE-BED REACTOR.

Author(s): Iannibello, Antonio Marengo, Sergio; Burgio, Gerlando; Baldi, Giancarlo; Sicardi, Silvio; Specchia, Vito Author Affiliation: Stazione Sperimentale per i Combustibili, Milan, Italy Source: Ind Eng Chem Process Des Dev v 24 n 3 Jul 1985 p 531-537 ISSN: 0019-7882 CODEN: IEPDAW Publication Year: 1985 Abstract: The removal of sulfur and metals from a heavy residual oil by hydrotreating in a pilot trickle-bed reactor was examined. Catalysts with different active components on two different supports (bauxite and alumina) were tested. The results were interpreted via several models that took into account the physical and chemical complexity of the three-phase system. A first-order kinetics approach proved valid for the bauxite-based catalysts, having a wide pore size distribution, provided that the hydrodynamic effects in the reactor had been suitably accounted for by either external liquid holdup or apparent intraparticle diffusivity. In contrast, the results from the alumina catalyst required interpretation with a different model, probably because of the different pore size distribution. 31 Refs. EI Order Number: 85080106901 HYDROCARBONS--Processing; CHEMICAL EQUIPMENT - Reactors; HYDRODYNAMICS; CATALYSTS - Alumina ;HYDROTREATING REACTIONS; HEAVY RESIDUAL OIL; PILOT TRICKLE-BED REACTOR Identifiers: HYDROTREATING REACTIONS; HEAVY RESIDUAL OIL; PILOT TRICKLE-BED REACTOR Classification Codes: 803 Document Type: JA Treatment: X 5 KINETIC MODELING OF THE OXIDATION OF GLUCOSE INTO GLUCONIC ACID USING A TRICKLE BED REACTOR. Author(s): Long, Nguyen Qui Germain, A. Author Affiliation: Univ de Liege, Inst de Chimie, Liege, Belg Source: Amer Inst Chem Eng Natl Eng Natl Meet 1985 Spring National Meeting and Petro Expo '85 - American Institute of Chemical Engineers. 1985 Houston, TX, USA Sponsored by: AIChE, New York, NY, USA AIChE New York, NY, USA 26p Paper: 70D CODEN: ACENC9 Publication Year: 1985 Abstract: A new continuous process was studied for the synthesis of gluconic acid by oxidation of glucose on a palladium catalyst. In order to optimize the productivity and the selectivity of the process, a kinetic model was developed based on data obtained in a continuous micro trickle bed reactor. This model correlates accurately the formation of gluconic acid as well as side products with the operating variables. It enables one to show that the very high catalyst loading of trickle bed reactors can considerably improve the selectivity of reactions normally realized in slurry reactors. 9 Refs. EI Order Number: 85080111069 SUGAR--Oxidation; CHEMICAL REACTIONS - Reaction Kinetics; CHEMICAL EQUIPMENT - Reactors; CATALYSTS; ACIDS - Manufacture; PALLADIUM AND ALLOYS ;GLUCONIC ACID; CONTINUOUS

MICRO TRICKLE BED REACTOR; GLUCONOBACTER; ASPERGILLUS NIGER Identifiers: GLUCONIC ACID; CONTINUOUS MICRO TRICKLE BED REACTOR; GLUCONOBACTER; ASPERGILLUS NIGER Classification Codes: 822 Document Type: CA 6 MODELLING OF A TRICKLE-BED REACTOR - THE HYDROGENATION OF XYLOSE TO XYLITOL. Author(s): Herskowitz, M. Author Affiliation: Ben Gurion Univ of the Negev, Dep of Chemical Engineering, Beer Sheva, Isr Source: Chem Eng Sci v 40 n 7 1985 p 1309-1311 ISSN: 0009-2509 CODEN: CESCAC Publication Year: 1985 Abstract: The purpose of this paper is to develop a model for predicting the conversion of xylose to xylitol in a trickle-bed reactor. The hydrogen and xylose concentrations in the liquid are calculated as a function of the liquid and gas superficial velocities, the pressure and temperature in the reactor. Since the hydrogen concentration in the liquid is at least two orders of magnitude smaller than the xylose concentration while the diffusivity of hydrogen in the liquid is only five times larger than the diffusivity of xylose, the assumption that the concentration of xylose is uniform in the catalyst pores is justified. 24 Refs. EI Order Number: 85100138998 CHEMICAL EQUIPMENT--Reactors; CHEMICAL REACTIONS - Hydrogenation ;TRICKLE-BED REACTOR; XYLOSE; XYLITOL Identifiers: TRICKLE-BED REACTOR; XYLOSE; XYLITOL Classification Codes: 802 Document Type: JA Treatment: X 7 MODELING OF TRICKLE BED REACTORS AT HIGH TEMPERATURES AND PRESSURES WITH VOLATILE FEEDS. Author(s): Collins, George M. Hess, Richard K.; Hook, Bruce D.; Akgerman, Aydin Author Affiliation: Texas A&M Univ, Kinetics, Catalysis & Reaction Engineering Lab, College Station, TX, USA Source: Annu Meet Am Inst Chem Eng 1984 Annual Meeting - American Institute of Chemical Engineers. 1984 San Francisco, CA, USA Sponsored by: AIChE, New York, NY, USA AIChE New York, NY, USA 31p Paper: 108B ISSN: 0196-7282 CODEN: AMAEDX Publication Year: 1984 Abstract: The purpose of this study was to develop a model to predict the behavior of trickle beds when the liquid feed is volatile. The model developed is compared with a non-volatile liquid phase model employing the same kinetics. In the model it is assumed that the reactor is operating in plug flow and that there is no significant wall flow, the catalyst bed is completely wetted, the mass transfer effects are negligible, the feed is volatile, and that the reaction takes place on the wetted catalyst in the liquid phase. It is intended to apply this model to hydrotreating processes which take place at high temperatures and pressures with partial vaporization of the feed. 40 Refs. EI Order Number: 85040053530 CHEMICAL EQUIPMENT--Reactors; CATALYSTS; CHEMICAL REACTIONS - Hydrogenation; CHEMICAL ENGINEERING - Mathematical Models; FLOW OF FLUIDS - Packed Beds; LIQUIDS -

Chemical Reactions ;TRICKLE BEDS; PLUG FLOW; WALL FLOW; HYDROTREATING; VOLATILE LIQUID FEEDS Identifiers: TRICKLE BEDS; PLUG FLOW; WALL FLOW; HYDROTREATING; VOLATILE LIQUID FEEDS Classification Codes: 802 Document Type: CA 8 MODELLING AND DESIGN OF A TRICKLE BED REACTOR. Author(s): Sicardi, S. Author Affiliation: Politecnico di Torino, Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, Turin, Italy Source: Institution of Chemical Engineers Symposium Series ISCRE 8, The Eighth International Symposium on Chemical Reaction Engineering. n 87 1984 Edinburgh, Scotl Sponsored by: Inst of Chemical Engineers, Rugby, Engl Inst of Chemical Engineers (EFCE Event n 299) Rugby, Engl p 169-176 ISSN: 0307-0492 CODEN: ICESDB ISBN: 0-85295-176-0 Publication Year: 1984 Abstract: In a trickle bed reactor, when a volatile key reactant is controlling, the experimental conversion rate is generally higher than that determined with the model of totally wetted particles. The models proposed to interpret this phenomenon are based on very different approaches and, at the present, are not completely reliable for the design of the trickle bed reactor. An empirical correlation for the evaluation of the conversion rate is proposed: it is obtained from the experimental data taken from the literature and is valid for three different reactions. It is useful information for reactor design. 11 Refs. EI Order Number: 85060080026 CHEMICAL REACTIONS--Reaction Kinetics; CHEMICAL EQUIPMENT - Reactors; CATALYSIS - Performance; CATALYSIS - Mathematical Models ;TRICKLE BED REACTOR; VOLATILE KEY REACTANT; CONVERSION RATES; TOTALLY WETTED PARTICLES; MICROKINETICS Identifiers: TRICKLE BED REACTOR; VOLATILE KEY REACTANT; CONVERSION RATES; TOTALLY WETTED PARTICLES; MICROKINETICS Classification Codes: 802 Document Type: CA 9 MODELLING OF A GAS-SOLID TRICKLE FLOW REACTOR FOR THE CATALYTIC OXIDATION OF HYDROGEN SULPHIDE TO ELEMENTAL SULPHUR. Author(s): Verver, A. B. Swaay, W. P. M. Author Affiliation: Akzo Engineering BV, Arnhem, Neth Source: Institution of Chemical Engineers Symposium Series ISCRE 8, The Eighth International Symposium on Chemical Reaction Engineering. n 87 1984 Edinburgh, Scotl Sponsored by: Inst of Chemical Engineers, Rugby, Engl Inst of Chemical Engineers (EFCE Event n 299) Rugby, Engl p 177-184 ISSN: 0307-0492 CODEN: ICESDB ISBN: 0-85295-176-0 Publication Year: 1984 Abstract: The gas-solid trickle flow contactor is studied as a reactor for desulfurization of gases with small amounts of H//2S producing elemental sulfur. Experiments on the conversion of H//2S and O//2 and on mass transfer performance have been carried out in a bench-scale pilot plant at 150 to 300 degree C. The performance is

described by two reactor models. The first model considers only mass transfer between gas and solid particles in series with reaction, and the other takes account of diffusion phenomena in the gas-solids emulsion (trickles) in parallel with reaction. At increasing temperature, mass transfer phenomena show an increasingly important limitation for the conversion rate. Results show the influence of trickle formation. 7 Refs. EI Order Number: 85060080028 SULFUR COMPOUNDS--Oxidation; CHEMICAL EQUIPMENT - Reactors; AIR POLLUTION - Control; CATALYSTS - Zeolites; CATALYSIS - Mathematical Models ;DRY DESULFURIZATION; HYDROGEN SULFIDE; GAS-SOLID TRICKLE FLOW REACTOR; BENCH-SCALE TESTING Identifiers: DRY DESULFURIZATION; HYDROGEN SULFIDE; GAS-SOLID TRICKLE FLOW REACTOR; BENCH-SCALE TESTING Classification Codes: 804 Document Type: CA 10 OXIDATION OF SULFUR DIOXIDE IN A TRICKLE-BED REACTOR: A STUDY OF REACTOR MODELLING. Author(s): Berruti, F. Hudgins, R. R.; Rhodes, E.; Sicardi, S. Author Affiliation: Univ of Waterloo, Dep of Chemical Engineering, Waterloo, Ont, Can Source: Can J Chem Eng v 62 n 5 Oct 1984 p 644-650 ISSN: 0008-4034 CODEN: CJCEA7 Publication Year: 1984 Abstract: In the reported experiments, the catalytic oxidation of sulfur dioxide on activated carbon by oxygen in the presence of water was carried out to study a laboratory-scale trickle-bed reactor. The particular aim of this study was to develop empirical models describing the reactor behavior for reactions in which the controlling reactant is in the gas phase. Water and various gaseous SO//2-air-O//2 mixtures were fed co-currently downward through a fixed bed of small carbon particles wetted to various degrees. The liquid distribution nozzle was designed to minimize entrance disturbances. Sulfuric acid product was analyzed by conventional titration methods. The experimental data are satisfactorily interpreted by either of two different models: one considers that the external area of the catalyst is divided into two zones (wetted and dry) both active with respect to mass transfer; the other assumes that only one zone of the external area involves mass transfer and that the mass transfer coefficient must be calculated according to film theory. 15 Refs. EI Order Number: 84120221396 Subjects: SULFUR DIOXIDE; CHEMICAL EQUIPMENT - Reactors; MATHEMATICAL MODELS; CATALYSTS - Activated Carbon; OXYGEN; WATER ;TRICKLE-BED REACTORS Identifiers: TRICKLE-BED REACTORS

11 PERFORMANCE OF A PILOT TRICKLE-BED REACTOR FOR HYDROTREATING OF PETROLEUM FRACTIONS: DYNAMIC ANALYSIS. Author(s): Iannibello, Antonio Marengo, Sergio; Guerci, Alessandro; Baidi, Giancarlo; Sicardi, Silvio Author Affiliation: Stazione Sperimentale per i Combustibili, Milan, Italy Source: Ind Eng Chem Process Des Dev v 22 n 4 Oct 1983 p 594-598 ISSN: 0019-7882 CODEN: IEPDAW

Publication Year: 1983 Abstract: The total liquid holdup and the intraparticle apparent diffusivity have been measured in a pilot trickle-bed reactor by a dynamic method. Different liquids and catalyst particles were tested. The total holdup show that pore filling of the catalyst may be considered as total even at very low liquid flow rate and at a relatively high temperature. The apparent intraparticle diffusivity is in line with that measured in bench scale reactors and with other liquid phases. 22 Refs. EI Order Number: 84020018842 Subjects: CHEMICAL EQUIPMENT; HYDROCARBONS - Processing Classification Codes: 802 12 TRICKLE-BED REACTORS: A REVIEW. Author(s): Herskowitz, Mordechay Smith, J. M. Author Affiliation: Ben Gurion Univ of the Negev, Beer Sheva, Isr Source: AIChE J v 29 n 1 Jan 1983 p 1-18 ISSN: 0001-1541 CODEN: AICEAC Publication Year: 1983 Abstract: In the last few years experimental and theoretical studies that contribute to improved design and scaleup of trickle-bed reactors have been published. The scope of this study is to review critically these improvements. Progress in understanding local rates of reaction is considered first. Then recent developments in reactor design are analyzed. 110 Refs. EI Order Number: 83050061600 Subjects: CHEMICAL EQUIPMENT; CATALYSTS ;TRICKLE BED REACTORS Identifiers: TRICKLE BED REACTORS Classification Codes: 802 13 COMPARISON OF CURRENT MODELS FOR TRICKLE-BED REACTORS WITH APPLICATION TO A MODEL REACTION SYSTEM. Author(s): Mills, P. L. Dudukovic, M. P. Author Affiliation: Monsanto Co, St. Louis, Mo, USA Source: Preprints -Division of Petroleum Chemistry American Chemical Society Preprints - Division of Petroleum Chemistry, American Chemical Society, Volume 28, Number 2: Symposia. v 28 n 2 Feb 1983 Seattle, WA, USA Sponsored by: ACS Div of Petroleum Chemistry, Washington, DC, USA ACS Washington, DC, USA p 525 ISSN: 0569-3799 CODEN: ACPCAT Publication Year: 1983 Subjects: CHEMICAL EQUIPMENT; ;COCURRENT DOWNFLOW OF GAS ON LIQUID REACTANTS; LIQUID-PHASE HYDROGENATION AND OXIDATION; HYDRODESULFURIZATION OF PETROLEUM FEEDSTOCKS; HYDRODENITROGENATION OF COAL LIQUIDS; TRICKLE-BED REACTOR PERFORMANCE PREDICTION; ABSTRACT ONLY Identifiers: COCURRENT DOWNFLOW OF GAS ON LIQUID REACTANTS; LIQUID-PHASE HYDROGENATION AND OXIDATION; HYDRODESULFURIZATION OF PETROLEUM FEEDSTOCKS; HYDRODENITROGENATION OF COAL LIQUIDS; TRICKLE-BED REACTOR PERFORMANCE PREDICTION; ABSTRACT ONLY Classification Codes: 802 Document Type: CA 14 TRICKLE-BED REACTORS: DYNAMICS TRACER TESTS, REACTION STUDIES AND MODELING OF REACTOR PERFORMANCE.

Author(s): El-Hisnawi, A. A. Dudukovic, M. P.; Mills, P. L. Author Affiliation: Washington Univ, St. Louis, Mo, USA Source: ACS Symp Ser Chemical Reaction Engineering - Boston Develped in Advance of the 7th International Symposium on Chemical Reaction Engineering. 1982 Boston, Mass, USA Sponsored by: ACS, Washington, DC, USA ACS Washington, DC, USA p 421-440 CODEN: ACSMC8 ISBN: 0-8412-0732-1 Publication Year: 1982 Subjects: CHEMICAL EQUIPMENT; ;GAS-PHASE, RATE LIMITING REACTANT; LIQUID-SOLID CONTRACTING EFFICIENCY; GAS-LIQUID-SOLID MASS TRANSFER COEFFICIENTS; REACTOR PERFORMANCE PREDICTION; RATE LIMITING CHARACTERISTICS; NON-INTERACTING GAS-LIQUID REGIME Identifiers: GAS-PHASE, RATE LIMITING REACTANT; LIQUID-SOLID CONTRACTING EFFICIENCY; GAS-LIQUID-SOLID MASS TRANSFER COEFFICIENTS; REACTOR PERFORMANCE PREDICTION; RATE LIMITING CHARACTERISTICS; NON-INTERACTING GAS-LIQUID REGIME Classification Codes: 802 Document Type: CA 15 DESIGN AND SCALE-UP OF TRICKLE BED REACTORS. SOLID-LIQUID CONTACTING EFFECTIVENESS. Author(s): Baldi, Giancarlo Author Affiliation: Politecnico of Torino, Istituto di Chimica Industriale, Turin, Italy Source: NATO Advanced Study Institutes Series, Series E, Applied Sciences Multiphase Chemical Reactors. Volume II - Design Methods n 52 1981 Vimeiro, Port Sponsored by: NATO Advanced Study Inst Sijthoff & Noordhoff, Alphen aan den Rijn, Neth and Rockville, Md, USA p 323-341 ISSN: 0304-9930 CODEN: NASEDC ISBN: 90-286-2821-5 Publication Year: 1981 Subjects: CHEMICAL EQUIPMENT; ;DESIGN AND SCALE-UP OF TRICKLE BED REACTORS; SOLID-LIQUID CONTACTING EFFECTIVENESS; MICROKINETICS; HYDRODYNAMICS; SOLID-LIQUID EFFECTIVENESS FACTOR; CATALYST WETTING Identifiers: DESIGN AND SCALE-UP OF TRICKLE BED REACTORS; SOLID-LIQUID CONTACTING EFFECTIVENESS; MICROKINETICS; HYDRODYNAMICS; SOLID-LIQUID EFFECTIVENESS FACTOR; CATALYST WETTING Classification Codes: 802 Document Type: CA 16 DYNAMICS OF A TRICKLE-BED HYDROCRACKER WITH A QUENCHING SYSTEM. Author(s): Yan, T. Y. Author Affiliation: Mobil Res & Dev Corp, Princeton, NJ Source: Can J Chem Eng v 58 n 2 Apr 1980 p 259-266 ISSN: 0008-4034 CODEN: CJCEA7 Publication Year: 1980 Abstract: A mathematical model has been developed to simulate the dynamic behavior of a trickle-bed hydrocracker without and with one quench. The model was used to study the effects of parameters on transient temperature and hydrocarbon feed profiles. The system was found to be very sensitive to inlet temperatures and the states of catalyst activity. The model can be used to guide design and operation of a quenching system, i. e. , proper

location, starting time, and quantity of quench stream, to prevent excess temperature rise that would otherwise lead to left double quote run-away right double quote condition and poor product yields. 18 Refs. EI Order Number: 80110002035 Subjects: CHEMICAL EQUIPMENT; CHEMICAL REACTIONS - Hydrocracking; MATHEMATICAL MODELS; DYNAMICS ;TRICKLED-BED REACTORS Identifiers: TRICKLED-BED REACTORS Classification Codes: 802 17 AXIAL DISPERSION OF GAS AND SOLID PHASES IN A GAS-SOLID PACKED COLUMN AT TRICKLE FLOW. Author(s): Roes, A. W. M. van Swaaij, W. P. M. Author Affiliation: Twente Univ of Technol, Enschede, Neth Source: Chem Eng J (Lausanne) v 18 n 1 Aug 1979 p 13-28 ISSN: 0300-9467 CODEN: CMEJAJ Publication Year: 1979 Abstract: Axial dispersion of gas and solid phases in a gas-solid packed column at trickle flow, a promising new countercurrent operation, was evaluated using residence time distribution (RTD) experiments. The column was packed with dumped Pall rings, the gas phase was air at ambient conditions and the solid was a porous catalyst carrier. At a given solid flow rate axial dispersion of the gas phase decreases with increasing gas velocity and is strongly dependent upon solid mass flux. Axial dispersion of the solid phase is approximately independent of the gas velocity and it is reduced if the solid mass flux is increased. For conditions of practical importance, 2-5 and 5-15 Pall ring layers correspond to the height of a mixing unit in the gas and solid phase, respectively. 23 Refs. EI Order Number: 80010000366 Subjects: FLOW OF FLUIDS; HEAT TRANSFER; MASS TRANSFER ;COUNTERCURRENT OPERATION Identifiers: COUNTERCURRENT OPERATION Classification Codes: 631TRICKLE-BED REACTORS. Author(s): Ng, K. M. Chu, C. F. Author Affiliation: Univ of Massachusetts, Amherst, MA, USA Source: Chem Eng Prog v 83 n 11 Nov 1987 p 55-63 ISSN: 0009-2495 CODEN: CEPRA8 Publication Year: 1987 Abstract: Trickle-bed reactors can be defined as a fixed bed of catalyst particles, contacted by a gas-liquid, two-phase flow. The flow may be cocurrent (downflow or upflow) or countercurrent. In this article, cocurrent downflow is considered, which, because of its relatively lower pressure drop and the absence of flooding, is by far the most common mode of operation in industrial practice. Trickle-bed reactors are used primarily in the petroleum industry for hydrocracking, hydrodesulfurization, and hydrodenitrogenation. Many basic aspects of trickle-bed reactors are not yet fully understood, making design from fundamentals very difficult. The axial Peclet number in the trickling regime, which is in agreement with the experimental data, is relatively independent of the liquid flow rate. 10 Refs. EI Order Number: 88030036194 CHEMICAL EQUIPMENT--Reactors; FLOW OF FLUIDS - Two Phase; PETROLEUM REFINERIES -

Equipment; PETROLEUM REFINING - Nitrogen Removal; HYDROCARBONS - Hydrocracking ;TRICKLE-BED REACTORS DESIGN; GAS-LIQUID SYSTEM; COCURRENT DOWNFLOW; CATALYST PARTICLES; CATALYST FIXED BED Identifiers: TRICKLE-BED REACTORS DESIGN; GAS-LIQUID SYSTEM; COCURRENT DOWNFLOW; CATALYST PARTICLES; CATALYST FIXED BED Classification Codes: 802 Document Type: JA Treatment: GX 2 SIMPLE MULTICOMPONENT DESCRIPTION OF THE INFLUENCE OF THE PARTICLE AND PORE SIZE OF COMMERCIAL CATALYSTS ON THE HYDRODESULFURIZATION OF HEAVY GAS OIL IN (SMALL) TRICKLE-FLOW REACTORS. Author(s): Gosselink, J. W. Stork, W. H. J. Author Affiliation: Shell Research BV, Amsterdam, Neth Source: Chem Eng Process v 22 n 3 Nov 1987 p 157-162 ISSN: 0255-2701 CODEN: CENPEU Publication Year: 1987 Abstract: Catalysts for the catalytic hydrodesulfurization (HDS) process are still being improved, for instance by optimization of particle size and shape and pore structure. They are generally tested in small-scale trickle-flow equipment. A simple multicomponent model has been developed to describe the influence of the particle and pore sizes on the heavy gas oil HDS performance in such equipment. The model is based on both the diffusion through the catalyst pores and the chemical HDS reaction on the catalyst inner surface of the individual sulfur components. It makes use of a broad distribution function for the HDS reaction rate constants k, and assumes that all the components have the same effective diffusion coefficient less than D greater than . This model, which has the mean value of k, this is less than k greater than , and less than D greater than as the only two parameters, gives an excellent description of the HDS performance of Co/Mo/A1//2O//3 catalysts over broad ranges of space velocities and catalyst particle sizes. (Author abstract) 23 Refs. EI Order Number: 88020020604 GAS OIL--Desulfurization; CATALYSTS - Porosity; PARTICLE SIZE ANALYSIS - Mathematical Models; DIFFUSION - Optimization; POROUS MATERIALS - Mass Transfer; CHEMICAL EQUIPMENT - Reactors ;HEAVY GAS OIL HYDRODESULFURIZATION; TRICKLE FLOW REACTORS; CATALYST PARTICLE SIZE EFFECT; CATALYST PORE SIZE EFFECT; PARTICLE SIZE OPTIMIZATION Identifiers: HEAVY GAS OIL HYDRODESULFURIZATION; TRICKLE FLOW REACTORS; CATALYST PARTICLE SIZE EFFECT; CATALYST PORE SIZE EFFECT; PARTICLE SIZE OPTIMIZATION Classification Codes: 523 Document Type: JA Treatment: NTX 3 TRICKLE-BED REACTORS: LIQUID DIFFUSIONAL EFFECTS IN A GAS-LIMITED REACTION. Author(s): Beaudry, E. G. Dudukovic, M. P.; Mills, P. L. Author Affiliation: Washington Univ, St. Louis, MO, USA Source: AIChE J v 33 n 9 Sep 1987 p 1435-1447 ISSN: 0001-1541 CODEN: AICEAC Publication Year: 1987 Abstract: A model is developed for predicting the performance of a partially wetted trickle-bed reactor for a

gas-limiting reaction of order less than or equal to one. The model indicates that under certain conditions the liquid reactant may affect the reaction rate due to its inability to rapidly diffuse to catalyst areas that are in direct contact with the gas. This model is the first to explain and predict on a rational basis the experimental results for the hydrogenation of diluted alpha -methylstyrene and aqueous maleic acid reported in the literature. A criterion that determines when liquid reactant effects can be expected is developed and reported. (Author abstract) 31 Refs. EI Order Number: 87120192853 CHEMICAL EQUIPMENT--Reactors; ORGANIC COMPOUNDS - Hydrogenation; CATALYSTS - Wetting; ACIDS - Hydrogenation; MASS TRANSFER; GASES ;TRICKLE-BED REACTORS; LIQUID DIFFUSIONAL EFFECTS; GAS-LIMITED REACTION; MALEIC ACID Identifiers: TRICKLE-BED REACTORS; LIQUID DIFFUSIONAL EFFECTS; GAS-LIMITED REACTION; MALEIC ACID Classification Codes: 802 Document Type: JA Treatment: TX 4 GAS-SOLID TRICKLE-FLOW REACTOR FOR THE CATALYTIC OXIDATION OF HYDROGEN SULPHIDE: A TRICKLE-PHASE MODEL. Author(s): Verver, A. B. Van Swaaij, W. P. M. Author Affiliation: Twente Univ of Technology, Enschede, Neth Source: Chem Eng Sci v 42 n 3 1987 p 435-445 ISSN: 0009-2509 CODEN: CESCAC Publication Year: 1987 Abstract: The oxidation of H//2S by O//2 producing elemental sulfur has been studied at temperatures of 100-300 degree C and at atmospheric pressure in a laboratory-scale gas-solid trickle-flow reactor. In order to describe mass transfer in the trickle-flow reactor, a reactor model has been developed in which a particle-free, upflowing gas phase and a dense, downflowing gas-solids suspension, the so-called trickle phase, are distinguished. From the experiments and from the reactor model calculations it appears that for the H//2S-O//2 reaction no mass transfer limitations occur at temperatures up to about 200 degree C, whereas at 300 degree C gas-phase mass transfer and diffusion within the dense solids suspensions offer resistance to reaction. (Edited author abstract) 16 Refs. EI Order Number: 87070105627 HYDROGEN SULFIDE--Oxidation; CHEMICAL EQUIPMENT - Reactors; SOLIDS - Suspensions; MASS TRANSFER; ZEOLITES ;GAS-SOLID TRICKLE-FLOW REACTOR; TRICKLE-PHASE MODEL; TRICKLE PHASE Identifiers: GAS-SOLID TRICKLE-FLOW REACTOR; TRICKLE-PHASE MODEL; TRICKLE PHASE Classification Codes: 931 Document Type: JA Treatment: TX 5 CATALYTIC HYDROTREATING OF BITUMEN DERIVED COKER GAS OIL: A MODIFIED KINETIC MODEL FOR PILOT AND COMMERCIAL PLANTS. Author(s): Yui, S. M. Sanford, E. C. Author Affiliation: Syncrude Canada Ltd, Edmonton, Alberta, Can

Source: Preprints - Tenth Canadian Symposium on Catalysis. 1986 Kingston, Ont, Can Sponsored by: Chemical Inst of Canada, Catalysis Div, Ottawa, Ont, Can Chemical Inst of Canada Ottawa, Ont, Can p 30-39 Publication Year: 1986 Abstract: A new kinetic model for hydrotreating of coker gas oil has been developed. First and 1. 5th order kinetics are applied to nitrogen (HDN) and sulfur removal (HDS), respectively. The model incorporates terms for hydrogen partial pressure (H//2PP) and catalyst wetting efficiency. By analyzing the pilot plant data, the power terms of 1. 3 (HDN) and 0. 8 (HDS) for H//2PP were obtained. The wetting efficiency of a commercial unit is assumed to be unity. The pilot scale trickle-bed, on the other hand, is only partially wetted; therefore, the plug flow assumption cannot be applied. The validity of the model was confirmed by commercial data. (Edited author abstract) 11 Refs. EI Order Number: 88030044950 GAS OIL--Processing; CHEMICAL REACTIONS - Reaction Kinetics; CATALYSTS - Wetting; CHEMICAL EQUIPMENT - Reactors; HYDROGEN - Pressure Effects ;COKER GAS OIL; CATALYTIC HYDROTREATING; CATALYST WETTING EFFICIENCY; PLUG FLOW; TRICKLE-BED REACTOR Identifiers: COKER GAS OIL; CATALYTIC HYDROTREATING; CATALYST WETTING EFFICIENCY; PLUG FLOW; TRICKLE-BED REACTOR Classification Codes: 523Modelling of catalytic SO$-2$/ oxidation for continuous and periodic liquid flow through a trickle bed Author(s): Stegasov, A.N.; Kirillov, V.A.; Silveston, P.L. Corporate Source: Siberian Branch of the Russian Acad of Science, Novosibirsk, Russia Source: Chemical Engineering Science v 49 n 22 Nov 1994 Pergamon Press Inc Tarrytown NY USA p 3699-3710 ISSN: 0009-2509 CODEN: CESCAC Publication Year: 1994 Abstract: SO$-2$/ oxidation over an activated carbon catalyst in a dynamically operated, adiabatic trickle bed can be described by a system of partial differential equations representing mass balances on four components in two phases, a fifth component only in the gas phase, two heat balances (one in the mixed fluid phase and the other for the stationary catalyst particles) and a total mass balance on the liquid phase. A stable, efficient algorithm has been developed to integrate the system of equations so as to predict the temperature profile in the bed and the acid concentration leaving the trickle bed. The adjustable parameter used to obtain the prediction, the wetting fraction, agrees well with experimental correlations of wetting vs liquid flow. The model is thus accurate. The effect of different kinetic models for SO$-2$/ oxidation on the simulations is examined. In English (Author abstract) 29 Refs. EI Order Number: 95012528892 Subjects: Oxidation; Reaction kinetics; Sulfur dioxide; Sulfuric acid; Activated carbon; Catalysts; Mathematical models; Differential equations; Algorithms; Integration; Wetting; Flow of fluids; Particles (particulate matter) Identifiers: Trickle bed; Intermittent liquid flow Classification Codes: 802.2

Document Type: JA Treatment: TX Record 2 Liquid-phase methanol synthesis: modelling of a monolithic reactor Author(s): Cybulski, Andrzej; Edvinsson, Rolf; Irandoust, Said; Andersson, Bengt Corporate Source: Delft Univ of Technology, Delft, Neth Source: Chemical Engineering Science v 48 n 20 Oct 1993 p 3463-3478 ISSN: 0009-2509 CODEN: CESCAC Publication Year: 1993 Abstract: A mathematical model of a monolithic reactor for liquid-phase methanol synthesis is developed. The performance of a commercial-scale monolithic reactor is simulated. The influence of various design parameters for different solvents and process conditions is studied. Over the range of process conditions considered, it was found that the mass transfer is sufficiently fast to allow the process to be operated essentially in the kinetic regime. The numerical results are compared with literature data on slurry columns, autoclaves and trickle-bed reactors. The performance of the monolithic reactor was found to be commensurable with these reactors. In view of some of the unique advantages of the monolithic reactor it can be a viable alternative to the conventional methanol reactors. In English (Author abstract) refs EI Order Number: 93111127433 Subjects: Chemical reactors; Mathematical models; Methanol; Synthesis (chemical); Performance; Mass transfer; Reaction kinetics; Solvents Identifiers: Monolithic reactor; Liquid phase methanol synthesis; Design parameters; Kinetic regime; Process conditions Classification Codes: 802.1 Document Type: JA Treatment: AT Record 3 Simulation of hydrodewaxing reactor by stochastic method Author(s): Yang, Jianli; Li, Jianlong Corporate Source: Qingdao Inst of Chemical Technology, Qingdao, China Source: Journal of Chemical Engineering of Chinese Universities v 6 n 3 Sep 1992 p 264-270 ISSN: 1003-9015 CODEN: GHGXEG Publication Year: 1992 Abstract: An industrial reactor is divided into MXN reaction zones which are in series and parallel. A model for the conversion rate of the hydrodewaxing reaction in a given zone was derived from a pure death process and Sylvester-Pitayagulsarn model. The gas and liquid flow distributions in each zone were predicted by a Markov process with discrete state and discrete time is in agreement with the industrial operational data. The effects of the feed temperature and the feeding rate on the performances of the industrial hydrodewaxing reactor were also discussed in the paper. In Chinese (Edited author abstract) 8 Refs EI Order Number: 93050994396 Subjects: Chemical reactors; Dewaxing; Flow of fluids; Computer simulation Identifiers: Trickle bed; Hydrodewaxing Classification Codes: 802.1 Document Type: JA Treatment: X

Record 4 Modelling of non-catalytic reactions in a gas-solid trickle flow reactor. Dry, regenerative flue gas desulphurisation using a silica-supported copper oxide sorbent Author(s): Kiel, J.H.A.; Prins, W.; Van Swaaij, W.P.M. Corporate Source: Univ of Twente, Enschede, Neth Source: Chemical Engineering Science v 47 n 17-18 Dec 1992 p 4271-4286 ISSN: 0009-2509 CODEN: CESCAC Publication Year: 1992 Abstract: A one-dimensional, two-phase axially dispersed plug flow model has been developed to describe the steady-state performance of a relatively new type of reactor, the gas-solid trickle flow reactor (GSTFR). In this reactor, an upward-flowing gas phase is contacted with a downward-flowing dilute solids phase over an inert packing. The model is derived from the separate mass and heat balances for both the gas and (porous) solids phases for the case of a non-catalytic gas-solid reaction, which is first-order in the gaseous reactant. The reaction rate may also depend on the solid reactant concentration, but this concentration is assumed to be low and uniform throughout the solids volume. From the model, axial profiles can be calculated numerically for the four independent variables, viz, the gas-phase and solids-phase temperatures and the concentrations of the gaseous and solid reactant. Under isothermal conditions, the model equations can be solved analytically; the resulting expressions for the axial profiles of the gaseous and solid reactant are presented. The model is applied to predict the flue gas desulphurisation performance of a full-scale GSTF absorber in a dry, regenerative process for the simultaneous removal of SO$-x$/ and NO$-x$/ from flue gases. In this process, to be operated at 350-400$DGR@C, the sorbent material consists of a porous silica support (spherical particles, 1.5 mm diameter) with 7.5 wt% CuO deposited on this support by an ion-exchange technique. The model calculations are based on experimental findings from previous studies regarding reaction kinetics, hydrodynamics of the two-phase flow, gas-solids mass transfer and testing of the integrated process in a bench-scale plant. It appears that SO$-2$/ removal efficiencies over 95% can be achieved in a GSTF absorber with a length of 15 m. In English (Edited author abstract) EI Order Number: 93010682094 Subjects: Chemical reactors; Flue gases; Desulfurization; Flow of fluids; Performance; Mathematical models; Adsorbents; Reaction kinetics; Silica; Copper oxides; Two phase flow; Temperature distribution; Hydrodynamics Identifiers: Trickle flow reactor; Gas phase axial profiles Classification Codes: 802 Document Type: JA Treatment: TX Record 5 Trickle-bed reactors. State of art and perspectives Author(s): Gianetto, A.; Specchia, V. Corporate Source: Politecnico di Torino, Italy Source: Chemical Engineering Science First International Conference on Gas-Liquid and Gas-Liquid-Solid Reactor Engineering Sep 13-16 1992 v 47 n 13-14 Sep-Oct 1992 Columbus, OH, USA p 3197-3218 ISSN: 0009-2509

CODEN: CESCAC Publication Year: 1992 Abstract: Theoretical and phenomenological aspects of trickle-bed reactors as reported in a wide number of papers of the last 35 years have been reviewed. The following engineering topics have been focused by trying a critical interpretation of the attained results: hydrodynamics, fluid-solid contacting, theoretical and semiempirical models, mass transfer phenomena, heat and pressure effects. The more recent themes considered in the literature and some important future trends of scientific and applied research have been enlightened. In English (Author abstract) 111 Refs EI Order Number: 92110624673 Subjects: Chemical reactors; Mathematical models; Hydrodynamics; Mass transfer; Heat transfer Identifiers: Trickle bed reactors; Catalyst wetting; Fluid solid contacting; Wetting efficiency Classification Codes: 802.1 Document Type: JA Treatment: LTG Record 6 Multiphase reactors. Models and experimental verification Author(s): Dudukovic, M.P.; Devanathan, N.; Holub, R. Corporate Source: Washington Univ, St. Louis, MO, USA Source: Revue de l'Institut Francais du Petrole v 46 n 4 Jul-Aug 1991 p 439-465 ISSN: 0020-2274 CODEN: RFPTBH Publication Year: 1991 Abstract: This paper addresses the issue of improving our understanding of the hydrodynamics in two commonly used reactor types: bubble columns and trickle beds. We use two different approaches. For the bubble column we develop and present a technique for measurement of liquid velocities and turbulence parameters in order to provide much needed data. We then suggest that this, coupled with another experimental technique for evaluation of voidage profiles, would yield all the necessary measurements for critical evaluation of the existing two phase flow models. In trickle-beds we develop a simple phenomenological model for liquid flow and confront it with the available data for pressure drop, holdup and flow regime transition. Based on this we develop a model for liquid distribution and suggest that quantification of any such model requires the use of noninvasive imaging technology of which we give an example. In English 50 Refs EI Order Number: 91100313157 Subjects: Chemical Reactors; Chemical Equipment--Bubble Columns; Hydrodynamics--Mathematical Models; Computer Aided Analysis; Flow of Fluids--Multiphase Identifiers: Trickle Beds; Computer Aided Radioactive Particle Tracking; Multiphase Reactors; Backmixing Parameters; Flow Regime Transition; Ergun Coefficients Classification Codes: 802 Document Type: JA Treatment: TXLRecord 1 Modelling of non-catalytic reactions in a gas-solid trickle flow reactor. Dry, regenerative flue gas desulphurisation using a silica-supported copper oxide sorbent Author(s): Kiel, J.H.A.; Prins, W.; Van Swaaij, W.P.M.

Corporate Source: Univ of Twente, Enschede, Neth Source: Chemical Engineering Science v 47 n 17-18 Dec 1992 p 4271-4286 ISSN: 0009-2509 CODEN: CESCAC Publication Year: 1992 Abstract: A one-dimensional, two-phase axially dispersed plug flow model has been developed to describe the steady-state performance of a relatively new type of reactor, the gas-solid trickle flow reactor (GSTFR). In this reactor, an upward-flowing gas phase is contacted with a downward-flowing dilute solids phase over an inert packing. The model is derived from the separate mass and heat balances for both the gas and (porous) solids phases for the case of a non-catalytic gas-solid reaction, which is first-order in the gaseous reactant. The reaction rate may also depend on the solid reactant concentration, but this concentration is assumed to be low and uniform throughout the solids volume. From the model, axial profiles can be calculated numerically for the four independent variables, viz, the gas-phase and solids-phase temperatures and the concentrations of the gaseous and solid reactant. Under isothermal conditions, the model equations can be solved analytically; the resulting expressions for the axial profiles of the gaseous and solid reactant are presented. The model is applied to predict the flue gas desulphurisation performance of a full-scale GSTF absorber in a dry, regenerative process for the simultaneous removal of SO$-x$/ and NO$-x$/ from flue gases. In this process, to be operated at 350-400$DGR@C, the sorbent material consists of a porous silica support (spherical particles, 1.5 mm diameter) with 7.5 wt% CuO deposited on this support by an ion-exchange technique. The model calculations are based on experimental findings from previous studies regarding reaction kinetics, hydrodynamics of the two-phase flow, gas-solids mass transfer and testing of the integrated process in a bench-scale plant. It appears that SO$-2$/ removal efficiencies over 95% can be achieved in a GSTF absorber with a length of 15 m. In English (Edited author abstract) EI Order Number: 93010682094 Subjects: Chemical reactors; Flue gases; Desulfurization; Flow of fluids; Performance; Mathematical models; Adsorbents; Reaction kinetics; Silica; Copper oxides; Two phase flow; Temperature distribution; Hydrodynamics Identifiers: Trickle flow reactor; Gas phase axial profiles Classification Codes: 802 Document Type: JA Treatment: TX Record 2 Trickle-bed reactors. State of art and perspectives Author(s): Gianetto, A.; Specchia, V. Corporate Source: Politecnico di Torino, Italy Source: Chemical Engineering Science First International Conference on Gas-Liquid and Gas-Liquid-Solid Reactor Engineering Sep 13-16 1992 v 47 n 13-14 Sep-Oct 1992 Columbus, OH, USA p 3197-3218 ISSN: 0009-2509 CODEN: CESCAC Publication Year: 1992 Abstract: Theoretical and phenomenological aspects of trickle-bed reactors as reported in a wide number of

papers of the last 35 years have been reviewed. The following engineering topics have been focused by trying a critical interpretation of the attained results: hydrodynamics, fluid-solid contacting, theoretical and semiempirical models, mass transfer phenomena, heat and pressure effects. The more recent themes considered in the literature and some important future trends of scientific and applied research have been enlightened. In English (Author abstract) 111 Refs EI Order Number: 92110624673 Subjects: Chemical reactors; Mathematical models; Hydrodynamics; Mass transfer; Heat transfer Identifiers: Trickle bed reactors; Catalyst wetting; Fluid solid contacting; Wetting efficiency Classification Codes: 802.1 Document Type: JA Treatment: LTG Record 3 Multiphase reactors. Models and experimental verification Author(s): Dudukovic, M.P.; Devanathan, N.; Holub, R. Corporate Source: Washington Univ, St. Louis, MO, USA Source: Revue de l'Institut Francais du Petrole v 46 n 4 Jul-Aug 1991 p 439-465 ISSN: 0020-2274 CODEN: RFPTBH Publication Year: 1991 Abstract: This paper addresses the issue of improving our understanding of the hydrodynamics in two commonly used reactor types: bubble columns and trickle beds. We use two different approaches. For the bubble column we develop and present a technique for measurement of liquid velocities and turbulence parameters in order to provide much needed data. We then suggest that this, coupled with another experimental technique for evaluation of voidage profiles, would yield all the necessary measurements for critical evaluation of the existing two phase flow models. In trickle-beds we develop a simple phenomenological model for liquid flow and confront it with the available data for pressure drop, holdup and flow regime transition. Based on this we develop a model for liquid distribution and suggest that quantification of any such model requires the use of noninvasive imaging technology of which we give an example. In English 50 Refs EI Order Number: 91100313157 Subjects: Chemical Reactors; Chemical Equipment--Bubble Columns; Hydrodynamics--Mathematical Models; Computer Aided Analysis; Flow of Fluids--Multiphase Identifiers: Trickle Beds; Computer Aided Radioactive Particle Tracking; Multiphase Reactors; Backmixing Parameters; Flow Regime Transition; Ergun Coefficients Classification Codes: 802 Document Type: JA Treatment: TXL Record 4 Thermal waves in the periodic operation of a trickle-bed reactor Author(s): Haure, Patricia M.; Bogdashev, S.M.; Bunimovich, M.; Stegasov, A.N.; Hudgins, R.R.; Silveston, P.L. Corporate Source: Univ Nacional de Mar del Plata, Mar del Plata, Argent Source: Chemical Engineering Science Eleventh International Symposium on Chemical Reaction Engineering - ISCRE 11: New Horizons for Reaction Engineering Jul 8-11 1990 v 45 n 8 1990 Toronto, Ont, Can p 2255-2261

ISSN: 0009-2509 CODEN: CESCAC Publication Year: 1990 Abstract: Periodic operation of a trickle-bed reactor with on-off liquid flow using SO$-2$/ oxidation over activated carbon at 26$DGR@C as a test reaction yields a large increase in the oxidation rate. A portion of this increase is due to a higher bed temperature. The on-off liquid flow causes a rising temperature front which is followed by a falling front in the direction of the liquid flow. These moving waves have been observed and are predicted by a dynamic trickle-bed reactor model which allows for gas-liquid mass transfer, product inhibition of reaction and evaporation. This model was used without fitted constants, but gave nevertheless a satisfactory representation of the experimental data. In English (Author abstract) 12 Refs EI Order Number: 90110059040 Subjects: Chemical Reactors; Sulfur Dioxide--Oxidation; Carbon--Activated; Mass Transfer Identifiers: Trickle-Flow Reactor; Thermal Waves; Periodic Operation; On-Off Liquid Flow-Cycling Classification Codes: 802 Document Type: JA Treatment: X Record 5 Novel model for reaction in trickle beds with flow maldistribution Author(s): Funk, Gregory A.; Harold, Michael P.; Ng, Ka M. Corporate Source: Univ of Massachusetts, Amherst, MA, USA Source: Industrial & Engineering Chemistry Research v 29 n 5 May 1990 p 738-748 ISSN: 0888-5885 CODEN: IECRED Publication Year: 1990 Abstract: The effect of liquid maldistribution on reaction in a trickle-bed reactor is examined by using a discrete model. It is based on a computer-generated, two-dimensional bed packed with equal-sized spherical catalyst pellets. The configuration of the liquid inlet distributor is included in the model. The flow on and intraparticle diffusion and reaction in each and every catalyst pellet are sequentially analyzed, leading to predictions of the overall reactor behavior. The interplay between flow patterns, wetting on individual pellets, and effectiveness enhancement is demonstrated. The present model offers advantages over other conventional models in terms of overall reaction rate predictions, the ability in the description of irregular morphological features, the absence of the artificial backmixing of materials, and others. In English (Author abstract) 44 Refs Subjects: Chemical Reactions; Chemical Reactors; Catalysts; Flow of Fluids--Computer Simulation; Computer Programming--Algorithms; Catalysis Identifiers: Trickle Beds; Flow Maldistribution; Trickle Bed Reactors Classification Codes: 802 Document Type: JA Treatment: TX Record 6 Steady-state models for SO$-2$/ oxidation in a trickle-bed reactor Author(s): Haure, Patricia M.; Hudgins, R.R.; Silveston, P.L. Corporate Source: Univ of Waterloo, Waterloo, Ont, Can Source: Chemical Engineering Journal and the Biochemical Engineering Journal v 43 n 3 May 1990 p 121-125 ISSN: 0300-9467 CODEN: CMEJAJ

Publication Year: 1990 Abstract: Published mathematical models for the steady-state operation of integral trickle-bed reactors are not all capable of predicting experimental results obtained for the catalytic oxidation of sulfur dioxide over activated carbon. Only the model of A.R. Mata and J.M. Smith, which considers variable gas composition within the reactor as well as the variability of the wetting efficiency with the liquid flow rate was successful. An empirical relationship between the wetting and the liquid flow rate was derived from steady-state data and found to coincide with that of M. Herskowitz. In English (Edited author abstract) 20 Refs Subjects: Sulfur Dioxide; Chemical Equipment--Reactors; Mathematical Models--Testing; Carbon--Activated Identifiers: Trickle-Bed Reactor; Steady State Models; Catalytic Oxidation; Model Predictions Classification Codes: 804 Document Type: JA Treatment: TX Record 7 Model for trickle bed reactors in view of changing gas velocity Author(s): Lekshmi-Narayanan, H.; Pan, Chin-Min; Haure, Patricia M.; Hudgins, R.R. Corporate Source: Univ of Waterloo, Waterloo, Ont, Can Source: Canadian Journal of Chemical Engineering v 68 n 2 Apr 1990 p 327-329 ISSN: 0008-4034 CODEN: CJCEA7 Publication Year: 1990 Abstract: The trickle-bed reactor model of S. Goto and J.M. Smith is modified to account for changes in the gas velocity as a result of the solubility of the active gaseous species in the liquid phase, its rate of uptake by the liquid, and the extent of its participation in the reaction. There appear to be practical cases for which changes in the velocity of the gas phase should not be ignored. In this note, we examine the conditions under which the constant gas velocity assumption can lead to significant errors. In English (Edited author abstract) 2 Refs Subjects: Chemical Equipment; Chemical Engineering - Mathematical Models; Flow of Fluids Identifiers: Trickle Bed Reactors; Material Balances; Reversible Reactions Classification Codes: 802 Document Type: JA Treatment: T Record 8 Mathematical modeling of a gas-liquid reaction in an irrigated catalyst bed reactor Author(s): Klinger, A.V.; Novikov, A.V.; Fedoseeva, T.V.; Popov, O.S. Corporate Source: Kalininsk Polytechnical Inst, USSR Source: Theoretical Foundations of Chemical Engineering (English Translation of Teoreticheskie Osnovy Khimicheskoi Tekhnologii) v 22 n 6 Jul 1989 p 520-525 ISSN: 0040-5795 CODEN: TFCEAU Publication Year: 1989 Abstract: A mathematical model was proposed to describe the process macrokinetics in a gas-liquid column-type reactors with an irrigated catalyst bed and the results of modeling compared with the experimental data. The model is based on mass transfer in liquid films. The process macrokinetics in the reactor, known as a trickle bed reactor, were experimentally studied for the case of glucose hydrogenation on a stationary nickel catalyst. In English (Edited author abstract) 30 Refs

Subjects: Catalysis; Chemical Equipment - Reactors; Glucose - Hydrogenation; Flow of Fluids - Films; Catalysts - Nickel; Mass Transfer - Mathematical Models Identifiers: Column Reactors; Differential Equations; Gas-Liquid Reactions; Irrigated Packed Bed Reactors; Liquid Film Mass Transfer; Trickle Bed Reactors Classification Codes: 802 Document Type: JA Treatment: TXPeriodic operation of trickle bed reactor for hydrogenolysis in gas-liquid-liquid-solid four phases Author(s): Yamada, Hiroshi; Goto, Shigeo Corporate Source: Nagoya Univ, Nagoya, Jpn Source: Journal of Chemical Engineering of Japan v 30 n 3 Jun 1997 Soc of Chemical Engineers, Jpn Tokyo Japan p 478-483 ISSN: 0021-9592 CODEN: JCEJAQ Publication Year: 1997 Abstract: Trickle bed reactors are the most common gas-liquid-solid three-phase reactors involving a solid catalyst, and gaseous and liquid reactants. If solvents in the liquid phase are indissoluble in each other, gas-liquid-liquid-solid four phases exist in the reactor. Deprotection of amino acid was studied in a trickle bed reactor as a typical example of a four-phase system. A reactant (carbobenzoxy phenylalanine) could be dissolved in an organic phase and hydrogenated to a product (phenylalanine) using a Pd/C solid catalyst. Phenylalanine had hydrophilic properties and transferred from the organic phase to the aqueous phase. When two liquids were continuously introduced into the four-phase reactor, the product (phenylalanine) was deposited on the surface of the catalyst and the catalytic activity gradually decreased. Periodic operation was adopted to solve this problem. Only distilled water was periodically introduced into the reactor to wash the catalyst, which could be completely regenerated after this washing period. The optimal reaction period was determined by simulation to obtain a high concentration of the product. In English (Author abstract) 5 Refs. EI Order Number: 97093813539 Subjects: Chemical reactors; Hydrogenation; Solvents; Amino acids; Catalyst activity; Aromatic compounds; Phase transitions; Dissolution Identifiers: Trickle bed reactors; Multiphase reactors Classification Codes: 802.3 Document Type: JA Treatment: G Record 2 Modelling of hydrotreating process in a trickle-bed reactor Author(s): Kumar, V. Ramesh; Balaraman, K.S.; Rao, V.S. Ramachandra; Ananth, M.S. Corporate Source: Indian Inst of Technology, Madras, India Source: Petroleum Science and Technology v 15 n 3-4 Apr-May 1997 Marcel Dekker Inc New York NY USA p 283-295 ISSN: 1091-6466 CODEN: PSTEFV Publication Year: 1997 Abstract: Pilot scale hydrotreating experiments have been conducted on straight run high speed diesel oil (SR HSDO) using commercially available Co-Mo on Al$-2$/O$-3$/ catalyst. Kinetics of hydrodesulphurization and hydrodenitrogenation are studied using the models that took into account the physical and chemical complexities of

the three phase system. Correlations are developed to predict the product properties based on operating conditions. The results show a good agreement with the experimental data. In English (Author abstract) 5 Refs. Subjects: Diesel fuels; Gas oils; Catalysts; Alumina; Chemical reactors; Reaction kinetics; Desulfurization; Correlation methods; Cobalt Identifiers: Hydrodenitrogenation; Hydrodesulphurization; Trickle bed reactors Classification Codes: 523 Document Type: JA Treatment: X Record 3 Analysis of rate enhancement in a periodically operated trickle-bed reactor Author(s): Gabarain, L.; Castellari, A.T.; Cechini, J.; Tobolski, A.; Haure, P. Corporate Source: Universidad Nacional de Mar del Plata Source: AIChE Journal v 43 n 1 Jan 1997 AIChE New York NY USA p 166-172 ISSN: 0001-1541 CODEN: AICEAC Publication Year: 1997 Abstract: When a trickle-bed reactor (TBR) is operated periodically, the bed is fed with liquid on and off, while the gas phase passes continuously. Rates and conversions could be higher than those corresponding to the steady-state operation. In the `dry cycles' the heat generated by the reaction can drive the vaporization of the liquid phase, and a much more rapid `gas phase' reaction may occur. There is a trade-off between the potential for hot-spot formation and the fact that overall rates are higher during cycling. A qualitative understanding of the phase transition in TBRs is obtained by a simple phenomenological model that takes into account different transport and reaction mechanisms occurring in a catalytic particle under different cycling conditions. A mathematical model is used to predict results. In English (Author abstract) 16 Refs. Subjects: Chemical reactors; Reaction kinetics; Vaporization; Thermal cycling; Phase transitions; Catalysts; Particles (particulate matter); Mathematical models; Mass transfer Identifiers: Trickle bed reactors; Hot spot formation; Dry cycles Classification Codes: 802.1 Document Type: JA Treatment: TX Record 4 Continuous lumping model for simulation of hydrocracking Author(s): Laxminarasimhan, C.S.; Verma, R.P.; Ramachandran, P.A. Corporate Source: Indian Oil Corp, Faridabad, India Source: AIChE Journal v 42 n 9 Sep 1996 AIChE New York NY USA p 2645-2653 ISSN: 0001-1541 CODEN: AICEAC Publication Year: 1996 Abstract: Hydrocracking of vacuum gas oil is an important chemical process involving complex reaction mixtures. The reaction is carried out in a trickle-bed reactor, considering reaction kinetics along with such hydrodynamic effects as mass transfer, intraparticle diffusion, and partial wetting. Since reaction kinetics is critical to modeling and simulation of a hydrocracking reactor, a modeling approach needs to capture the complex chemistry of the process, along with the elegance of the solution method. The complex chemistry of hydrocarbon is represented by an elegant

continuous lumping approach to modeling. The true boiling point of the mixture is used as the characterization parameter. Since the rate constant of hydrocracking is assumed to be a monotonic function of the true boiling point, it is possible to reformulate mass-balance equations in terms of rate constant as a continuous variable. A novel distribution function p(k,K), which determines the fractional yield distribution of species, was formulated based on data from the cracking patterns of various model compounds. Resulting integrodifferential equations are solved numerically to obtain yields of various fractions as a function of reactor residence time. Model predictions are compared with limited published data to show the utility of the model. In English (Author abstract) Refs. EI Order Number: 96103358237 Subjects: Hydrocracking; Computer simulation; Mathematical models; Gas oils; Reaction kinetics; Hydrodynamics; Chemical reactors; Integrodifferential equations; Probability; Computational fluid dynamics Identifiers: Continuous lumping model; Vacuum gas oil; Complex reaction mixtures; Trickle bed reactor; Hydrodynamic effects; Mass balance equation; Fractional yield distribution Classification Codes: 802.2 Document Type: JA Treatment: T Record 5 Interfacial mass transfer in trickle-bed reactor modelling Author(s): Toppinen, S.; Aittamaa, J.; Salmi, T. Corporate Source: Abo Akademi, Abo, Finl Source: Chemical Engineering Science v 51 n 18 Sep 1996 Pergamon Press Inc Tarrytown NY USA p 4335-4345 ISSN: 0009-2509 CODEN: CESCAC Publication Year: 1996 Abstract: A rigorous steady-state model was written for trickle-bed reactors. The mass and heat transfer resistances both between the gas phase and the liquid phase and between the liquid phase and the catalyst surface are included in the reactor model. The mass transfer is modelled using both the Maxwell-Stefan equations and the effective diffusivity method. The numerical solution of the model is discussed. The reactor model was attached to a flowsheet simulator that provided all the required physical property and phase-behaviour calculations. Finally, an industrial hydrogenation reactor was simulated as an example. The simulation results were used to examine the importance of local mass and heat transfer resistances in the reactor. In English (Author abstract) 24 Refs. EI Order Number: 96093332245 Subjects: Chemical reactors; Mass transfer; Heat transfer; Maxwell equations; Diffusion in gases; Diffusion in liquids; Computer simulation; Physical properties; Thermodynamic properties; Reaction kinetics; Mathematical models; Flowcharting Identifiers: Trickle bed reactors; Rigorous steady state model; Effective diffusivity method Classification Codes: 802.1 Document Type: JA Treatment: GT Record 6 Three-phase reactor model for hydrotreating in pilot trickle-bed reactors

Author(s): Korsten, Hans; Hoffmann, Ulrich Corporate Source: TU Clausthal, Clausthal-Zellerfeld, Ger Source: AIChE Journal v 42 n 5 May 1996 AIChE New York NY USA p 1350-1360 ISSN: 0001-1541 CODEN: AICEAC Publication Year: 1996 Abstract: A three-phase reactor model for describing the hydrotreating reactions in a trickle-bed reactor was developed. It includes correlations for determining mass-transfer coefficients, solubility data, and properties of the compounds under process conditions. The model, based on the two-film theory, was tested with regard to the hydrodesulfurization of vacuum gas oil in a new high-pressure pilot plant operated under isothermal conditions. The sulfur content of the product oil was found to depend strongly on the gas/oil flow ratio within the reactor. This is due to the inhibiting effect of hydrogen sulfide on the chemical reaction rates described by Langmuir-Hinshelwood kinetics. The poor conversion which, in contrast to industrial plants, is often observed in pilot plant reactors can be explained by incomplete catalyst wetting produced by low liquid velocities. The simulation shows a good agreement with the experiments carried out in a wide range of temperature, pressure, space velocity and gas/oil ratio. In English (Author abstract) Refs. EI Order Number: 96063207522 Subjects: Chemical reactors; Computer simulation; Chemical reactions; Correlation methods; Mass transfer; Solubility; Physical properties; Sulfur; Hydrogen sulfide; Reaction kinetics; Wetting Identifiers: Three phase reactor model; Hydrotreating reaction; Pilot trickle bed reactors; Mass transfer coefficient; Hydrodesulfurization; Vacuum gas oil; Two film theory; Langmuir-Hinshelwood kinetics Classification Codes: 802.1 Document Type: JA Treatment: G Record 7 Modelling of a trickle-bed reactor: II. The hydrogenation of 3-hydroxypropanal to 1,3-propanediol Author(s): Valerius, G.; Zhu, X.; Hofmann, H.; Arntz, D.; Haas, T. Corporate Source: Universitaet Erlangen-Nuernberg, Erlangen, Ger Source: Chemical Engineering and Processing v 35 n 1 Jan 1996 p 11-19 CODEN: CENPEU Publication Year: 1996 Abstract: 1,3-Propanediol can be synthesized by the hydrogenation of 3-hydroxypropanal over a nickel catalyst. The aim of the investigation was to obtain information about the mass transfer and degree of wetting in a trickle-bed reactor. The model for the concentration and temperature profiles in a pilot reactor employed was based on kinetic measurements in an autoclave. Two different approximations of the overall catalyst effectiveness factor were used: (1) the effectiveness factors of dry, half wetted and totally wetted slabs were weighted as proposed by Beaudry, Mills and Dudukovic: (2) a new cylinder shell model was used, leading to one-dimensional mass balance equations inside the porous catalyst particle for all possible values of the external wetting efficiency on the particle scale. In English (Author abstract) 14 Refs. EI Order Number: 96033109343 Subjects: Chemical reactors; Mathematical models; Hydrogenation; Organic compounds; Mass transfer; Wetting; Reaction kinetics; Catalysts; Nickel; Temperature measurement; Composition

Identifiers: Trickle bed reactor; Hydroxypropanal; Propanediol; Effectiveness factor; Cylinder shell model; Mass balance equations; Acrolein; Spinning basket reactors Classification Codes: 802.1 Document Type: JA Treatment: T Record 8 Modelling of a trickle-bed reactor: I. Extended definitions and new approximations Author(s): Valerius, G.; Zhu, X.; Hofmann, H. Corporate Source: Universitaet Erlangen-Nuernberg, Erlangen, Ger Source: Chemical Engineering and Processing v 35 n 1 Jan 1996 p 1-9 CODEN: CENPEU Publication Year: 1996 Abstract: Important ideas in the modelling of trickle-bed reactors given in the literature are summarized, partly extended and placed into context which, in future, will hopefully lead to a more satisfactory theory about the important physical and chemical processes in this type of reactor. Based on the common behaviour of different reaction systems and results of previous investigations, general model equations are formulated, which seem to be applicable to many reactions in a trickle-bed reactor. A new approximation for the overall catalyst effectiveness factor - the so-called cylinder shell model - is presented, which leads to one-dimensional mass balance equations inside the catalyst for all possible values of the external wetting efficiency on a particle scale. In English (Author abstract) 16 Refs. EI Order Number: 96033109342 Subjects: Chemical reactors; Mathematical models; Reaction kinetics; Approximation theory; Catalysts; Wetting; Mass transfer; Solubility; Gases; Catalyst deactivation Identifiers: Trickle bed reactor; Cylinder shell model; Mass balance equations; Effectiveness factor; Gaseous reactant; Mass transfer resistance Classification Codes: 802.1 Document Type: JA Treatment: T Record 9 Dynamic modelling of catalytic three phase reactors Author(s): Warna, J.; Salmi, T. Corporate Source: Abo Akademi, Abo, Finl Source: Computers & Chemical Engineering v 20 n 1 Jan 1996 Pergamon Press Inc Tarrytown NY USA p 39-47 ISSN: 0098-1354 CODEN: CCENDW Publication Year: 1996 Abstract: Dynamic models were developed for three phase slurry and trickle bed reactors operating in non-isothermal conditions. The model equations for the gas, liquid and catalyst phases consisted of parabolic partial differential equations (PDE) and ordinary differential equations (ODE), which were converted to ODEs using finite difference approximations for the spatial derivatives. The ODEs were solved by a stiff ODE solver (LSODE) using the backward difference method. The numerical strategy proved to be reliable. The reactor simulation programs were included in a flowsheet simulator. The use of the programs was illustrated with two case studies: oxidation of

SO$-2$/ and hydrogenation of toluene. The example simulations showed that the dynamic approach provides a meaningful path to the steady state of the reactor and gives valuable information of the reaction dynamics. In English (Author abstract) Refs. EI Order Number: 95112929965 Subjects: Chemical reactors; Computer simulation; Mathematical models; Partial differential equations; Finite difference method; Approximation theory; Numerical methods; Hydrogenation; Toluene; Oxidation; Sulfur dioxide; Convergence of numerical methods; Catalysis Identifiers: Catalytic three phase reactors; Trickle bed reactors; Ordinary differential equations; Backward difference method; Flowsheet simulator Classification Codes: 802.1 Document Type: JA Treatment: TX Record 10 Simulation of non-ideal flow in a trickle bed hydrotreater by the cross-flow model Author(s): Tsamatsoulis, Dimitris; Papayannakos, Nikos Corporate Source: Univ of Athens, Athens, Greece Source: Chemical Engineering Science v 50 n 23 Dec 1995 Pergamon Press Inc Tarrytown NY USA p 3685-3691 ISSN: 0009-2509 CODEN: CESCAC Publication Year: 1995 Abstract: The cross-flow model is used for the description of non-ideal behaviour of the liquid flow in a bench scale hydrotreater. Experimental data were received at reaction conditions using non-porous particles of various sizes. Total and static holdup and film thickness are correlated with liquid velocity and particle size. Mass transfer characteristic parameters are also correlated with liquid flow, particle size and bed porosity. System response simulation to stepwise feed tracer concentration change and best fit to experimental data yield the values of model parameters. In English (Author abstract) 17 Refs. EI Order Number: 96012991042 Subjects: Flow of fluids; Mathematical models; Computer simulation; Chemical reactors; Particles (particulate matter); Mass transfer; Particle size analysis; Fluidized beds; Porosity; Films Identifiers: Non-ideal flow; Trickle bed hydrotreater; Cross-flow model; Non-porous particles; Mass transfer characteristic parameters; Bed porosity; System response simulation; Feed tracer concentration change; Model parameters; Liquid velocity Classification Codes: 631.1 Document Type: JA Treatment: ATX Record 11 Multicomponent mass and energy transport on different length scales in a packed reactive distillation column for heterogeneously catalysed fuel ether production Author(s): Sundmacher, Kai; Hoffmann, Ulrich Corporate Source: Technische Universitaet Clausthal, Clausthal-Zellerfeld, Ger Source: Chemical Engineering Science Chemical Reaction Engineering: Science & Technology Proceedings of the 13th International Symposium on Chemical Reaction Engineering. Part A Sep 25-28 1994 v 49 n 24A Dec 1994 Baltimore, MD, USA 2 Pergamon Press Inc Tarrytown NY USA p 4443-4464 ISSN: 0009-2509 CODEN: CESCAC

Publication Year: 1994 Abstract: A reactive distillation column was operated which was packed with acid ion exchange rings catalysing the production of the octane enhancer methyl-tert.-butylether (MTBE) from methanol (MeOH) and isobutene (IB). Two types of catalytic rings were used: a block polymer (BP) with a capacity of 4.54 meq(H$+$PLU$/)/g and a glass supported precipitated polymer (GPP) with a capacity of 0.9 meq(H$+$PLU$/)/g. Fluid dynamic experiments with pure MeOH and pure MTBE show that the catalytic packings, which are located in the upper column section, work under trickle flow conditions. Nonreactive distillation experiments reveal sustained macroscale oscillations of fluxes, pressure and temperature that are caused by the distillation behaviour of the binary mixture MeOH/IB. These oscillations were also detected in the reactive distillation process with the highly stable, but less active GPP catalyst. The local compositions and temperatures from the nonoscillatory reactive distillation experiments with the BP catalyst are subjected to a detailed analysis of microscale solid-liquid and vapour-liquid transport resistances based on the Generalised Maxwell-Stefan approach. It turns out that the mass transport resistances inside the catalyst can vary significantly along the packing. The main mass transport resistance at the vapour-liquid interface is located on the liquid side. In English (Author abstract) 18 Refs. EI Order Number: 95042664673 Subjects: Ethers; Energy transfer; Mass transfer; Distillation columns; Catalysis; Methanol; Block copolymers; Fluid dynamics; Packing; Distillation; Composition; Catalysts Identifiers: Fuel ether; Catalytic ring; Packed reactive distillation column; Glass supported precipitated polymer; Acid ion exchange ring; Octane enhancer methyl tertiary butyl ether; Isobutene Classification Codes: 804.1 Document Type: JA Treatment: X Record 12 Modelling of biodegradation processes in trickle-bed bioreactors Author(s): Hekmat, D.; Vortmeyer, D. Corporate Source: Technical Univ of Munich, Munich, Ger Source: Chemical Engineering Science Chemical Reaction Engineering: Science & Technology Proceedings of the 13th International Symposium on Chemical Reaction Engineering. Part A Sep 25-28 1994 v 49 n 24A Dec 1994 Baltimore, MD, USA 2 Pergamon Press Inc Tarrytown NY USA p 4327-4345 ISSN: 0009-2509 CODEN: CESCAC Publication Year: 1994 Abstract: This paper deals with the mathematical modelling of a biological process to remove organic compounds from industrial waste gas. Modelling results will be compared with experimental data from measurements utilizing a laboratory-scale trickle-bed bioreactor. In such an apparatus, the biodegradation of the organic pollutants takes place via aerobic oxidation in biofilm, which is immobolized on a packing material. Two organic compounds were chosen as model pollutants, i.e. ethanol and polyakylated benzenes. In addition, data from the literature of a third

compound, dichloromethane, will be analysed. The mathematical model used in this work is based on the stationary differential mass balances along the reactor height together with the corresponding reaction terms. The experiments with ethanol reveal that over a large range of gas inlet concentrations, the rate limiting factor of the degradation process is oxygen limitation. The reason for this is the small partition coefficient of ethanol resulting in large liquid concentrations. Thus, the pollutant is mineralized at a relatively high rate until dissolved oxygen inside the biofilm is depleted. In these cases, model calculations with a zeroth-order reaction term describe the experimental data well. The experiments with polyalkylated benzenes reveal that substrate limitation occurs within the relevant range of gas inlet concentrations. The reason for this is the large partition coefficient resulting in small liquid concentrations. Thus, first-order reaction applies. Again, a rather good agreement of model and experiment is achieved. The analysis of the data of dichloromethane yields kinetic data within the transition regime of first-order and zeroth-order reaction rates. Thus, no significant difference is observed with the model calculations using either reaction order. The mathematical model presented can serve as a basis or proper design, up-scaling, and control strategies of trickle-bed bioreactors. In English (Author abstract) 21 Refs. EI Order Number: 95042664666 Subjects: Biodegradation; Mathematical models; Industrial waste treatment; Bioreactors; Oxidation; Biofilms; Ethanol; Benzene; Oxygen; Reaction kinetics; Chlorine compounds Identifiers: Polyalkylated benzene; Dichloromethane; Mass balance; Trickle bed bioreactor; Mineralization Classification Codes: 802.2 Document Type: JA Treatment: TX Record 13 Experimental and modeling study of kinetics and selectivity in the oxidation of a poly($alpha@-olefin) lubricant Author(s): Koh, Choon-Seok; Butt, John B. Corporate Source: Northwestern Univ, Evanston, IL, USA Source: Industrial & Engineering Chemistry Research v 34 n 2 Feb 1995 ACS Washington DC USA p 524-535 ISSN: 0888-5885 CODEN: IECRED Publication Year: 1995 Abstract: A major means of lubricant oil degradation is by oxidation in the presence of metal surfaces that can have catalytic activity. In this work an experimental and modeling study has been carried out on the oxidation kinetics and selectivity of a typical poly($alpha@-olefin) (PAO) lubricant in the presence of both inert (glass) and active (brass, steel) surfaces in the temperature range 170-240 $DGR@C. Inhibition of the reaction by zinc dialkyl dithiophosphate (ZDP) has been investigated. A batch recycling trickle-bed reactor system has been developed which provides reliable data on intrinsic chemical kinetics. Reaction rates are a strong function of temperature, with products appearing in the order of water, carbon dioxide, aldehydes, ketones, acids, and alcohols in both gas and

liquid phases. Significant changes in viscosity and molecular weight were observed for T $GRT 200 $DGR@C. A four-lump (PAO, carbonyl-containing compounds in the liquid phase, gaseous products, and deposits) kinetic model has been developed that gives good agreement with experimental results, including oxidation rate promotion by metals and inhibition by ZDP. In English (Author abstract) 48 Refs. EI Order Number: 95032625608 Subjects: Lubricants; Reaction kinetics; Catalyst selectivity; Oxidation; Degradation; Surfaces; Catalyst activity; Chemical reactors; Viscosity; Molecular weight; Mathematical models; Composition Identifiers: Poly(alpha olefin) lubricant; Catalytic metal surfaces; Zinc dialkyl dithiophosphate; Batch recycling trickle bed reactor; Chemical kinetics; Reaction rates Classification Codes: 607.1 Document Type: JA Treatment: TX Record 14 Partial wetting and forced reaction mixture transition in a model trickle-bed reactor Author(s): Ruzicka, Jiri; Hanika, Jiri Corporate Source: Czech Acad of Sciences, Czech Source: Catalysis Today Proceedings of the International Symposium on the Dynamics of Catalytic Systems Aug 29-Sep 3 1993 v 20 n 3 Aug 19 1994 Prague, Czech Repub Elsevier Science Publishers B.V. Amsterdam Neth p 467-484 ISSN: 0920-5861 CODEN: CATTEA Publication Year: 1994 Abstract: The model trickle-bed reactor had a trickle bed simulated as a vertical string of commercial catalyst cylindrical pellets. This paved the way for the separation and control of hydrodynamic regime effects to focus on the effects of mass and heat transfer and the influence or the model system used. The novel fixation of the catalyst pellets was to avoid their intrusion into the pellets which was the drawback of previous experimental arrangements. In English 12 Refs. EI Order Number: 94112441235 Subjects: Chemical reactors; Wetting; Catalysts; Mass transfer; Heat transfer; Packed beds; Mathematical models; Combustion; Hydrodynamics Identifiers: Trickle bed reactor; Light off Classification Codes: 802.1 Document Type: JA Treatment: X______________________________________________________________________________________