Design of a Chemical Pulse Reactor

1979 ◽  
Vol 34 (12) ◽  
pp. 1446-1451
Author(s):  
B. Denzel ◽  
F. F. Seelig
Keyword(s):  
Numerical Technique ◽  
Substrate Inhibition ◽  
Fixed Bed ◽  
Tubular Reactor ◽  
Fixed Bed Reactor ◽  
Low Flow ◽  
State Equations ◽  
Reactor Outlet ◽  
Catalytic Reactors ◽  
Two Phase

Abstract The general reaction X + Y + M → P + M may - due to substrate inhibition at the catalytic site M - give rise to bistability phenomena in an isothermal tubular fixed bed reactor. The parametric conditions for bistability in the single pellet are studied by a numerical technique. Solution of the steady state equations for a two phase model of the tubular reactor shows that narrow zones with high conversion are possible, similar to ignition zones in nonisothermal catalytic reactors. By a cyclic operation with alternating periods of charging the catalyst phase with substrate and discharging it by chemical reaction, pulses of high product concentration can be generated at the reactor outlet. This is demonstrated by simulation of the system assuming low flow velocity as it is characteristic for reaction columns with liquid mobile phase.

Modeling of a Fixed-Bed Reactor for the Production of Phthalic Anhydride

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Amir Rahimi ◽  
Sogand Hamidi
Keyword(s):  
Phthalic Anhydride ◽  
Fixed Bed ◽  
Tubular Reactor ◽  
Operating Conditions ◽  
Fixed Bed Reactor ◽  
Conversion Degree ◽  
Reactor Length ◽  
Reactor Temperature ◽  
Reported Data ◽  
Reactor Pressure

In this study, the performance of a fixed–bed tubular reactor for the production of phthalic anhydride is mathematically analyzed. The conversion degree and reactor temperature values are compared with the measured one in a tubular reactor applied in Farabi petrochemical unit in Iran as well as reported data in the literature for a pilot plate. The comparisons are satisfactory. The effects of some operating parameters including reactor length, feed temperature, reactor pressure, and existence of an inert in the catalytic bed are investigated. The optimum value of each parameter is determined on the basis of the corresponding operating conditions.

Methanol synthesis from CO2 and H2 in multi-tubular fixed-bed reactor and multi-tubular reactor filled with monoliths

2014 ◽  
Vol 92 (11) ◽  
pp. 2598-2608 ◽  
Author(s):  
Sofiane Arab ◽  
Jean-Marc Commenge ◽  
Jean-François Portha ◽  
Laurent Falk
Keyword(s):  
Methanol Synthesis ◽  
Fixed Bed ◽  
Tubular Reactor ◽  
Fixed Bed Reactor

Reactor Safety Analysis Based on a Developed Two-Phase Compressible Flow Simulation

Volume 1 ◽  
2004 ◽  
Author(s):  
A. F. Nowakowski ◽  
B. V. Librovich ◽  
L. Lue
Keyword(s):  
Multiphase Flow ◽  
Compressible Flow ◽  
Fluid Model ◽  
Numerical Technique ◽  
Computational Simulation ◽  
Safety Analysis ◽  
State Equations ◽  
Pressure Relief ◽  
Two Phase ◽  
Two Phases

The direct numerical simulation of multiphase flow is a challenging research topic with various key applications. In the present work, a computational simulation of multi-phase compressible flow has been proposed for safety analysis of chemical reactors. The main objective of a pressure relief system is to prevent accidents occurring from over pressurisation of the reactor. We are particularly interested in understanding the phenomena associated with emergency pressure relief systems for batch-type reactors and storage vessels. Existence of multiphase flow is significantly influenced by the interface between the phases and the associated discontinuities across the phase. The approach, which builds on the method first introduced by Saurel and Abgrall [1], was developed for solving two-phase compressible flow problems. Each phase is separately described by conservation equations. The interactions between two phases appear in the basic equations as transfer terms across the interface. The equations are complemented by state equations for the two phases and by additional correlations for the right-hand side coupling terms. The method is able to deal with multiphase mixtures and interface problems between compressible fluids. The key difference compared to classical two-fluid model is the presence of separate pressures fields associated with phases and introduction of pressure and velocity relaxation procedures. The relaxation operators tackle the boundary conditions at the interface and consequently the model is valid for fluid mixtures, as well as for pure fluids. The numerical technique requires the system to be decomposed and involves a non-conservative hyperbolic solver, an instantaneous pressure relaxation procedure and source term operators. The solution is obtained by succession of integrators using a second-order accurate scheme. The ultimate goal of this research is to use the method for studying the venting problem in reactor systems after verifying its performance on a series of standardised test cases documented in the literature.

scholarly journals Kinetic Study Based on the Carbide Mechanism of a Co-Pt/γ-Al2O3 Fischer–Tropsch Catalyst Tested in a Laboratory-Scale Tubular Reactor

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 717 ◽  
Author(s):  
Marco Marchese ◽  
Niko Heikkinen ◽  
Emanuele Giglio ◽  
Andrea Lanzini ◽  
Juha Lehtonen ◽  
...  
Keyword(s):  
Carbon Number ◽  
Fixed Bed ◽  
Tubular Reactor ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
Fischer Tropsch ◽  
Mechanism Model ◽  
Conversion Level ◽  
Temperature Programmed ◽  
Xrd Techniques

A Co-Pt/γ-Al2O3 catalyst was manufactured and tested for Fischer–Tropsch applications. Catalyst kinetic experiments were performed using a tubular fixed-bed reactor system. The operative conditions were varied between 478 and 503 K, 15 and 30 bar, H2/CO molar ratio 1.06 and 2.11 at a carbon monoxide conversion level of about 10%. Several kinetic models were derived, and a carbide mechanism model was chosen, taking into account an increasing value of termination energy for α-olefins with increasing carbon numbers. In order to assess catalyst suitability for the determination of reaction kinetics and comparability to similar Fischer–Tropsch Synthesis (FTS) applications, the catalyst was characterized with gas sorption analysis, temperature-programmed reduction (TPR), and X-ray diffraction (XRD) techniques. The kinetic model developed is capable of describing the intrinsic behavior of the catalyst correctly. It accounts for the main deviations from the typical Anderson-Schulz-Flory distribution for Fischer–Tropsch products, with calculated activation energies and adsorption enthalpies in line with values available from the literature. The model suitably predicts the formation rates of methane and ethylene, as well as of the other α-olefins. Furthermore, it properly estimates high molecular weight n-paraffin formation up to carbon number C80.

Hydrodynamics of co-current two-phase flow in an inclined rotating tubular fixed bed reactor — Wetting intermittency via periodic catalyst immersion

2015 ◽  
Vol 128 ◽  
pp. 147-158 ◽  
Author(s):  
Hans-Ulrich Härting ◽  
André Bieberle ◽  
Rüdiger Lange ◽  
Faïçal Larachi ◽  
Markus Schubert
Keyword(s):  
Two Phase Flow ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Phase Flow ◽  
Two Phase

Design consideration of dimethyl succinate production process

2014 ◽  
Vol 68 (12) ◽  
Author(s):  
Jozef Dudáš ◽  
Marcel Kotora ◽  
Michal Bradáč ◽  
Jozef Markoš
Keyword(s):  
Reactive Distillation ◽  
Process Analysis ◽  
Fixed Bed ◽  
Tubular Reactor ◽  
Fixed Bed Reactor ◽  
Process Conditions ◽  
Succinate Production ◽  
Analysis And Design ◽  
Simulation And Evaluation ◽  
Dimethyl Succinate

AbstractEsterification of succinic acid to form dimethyl succinate has been analysed and the process design is presented in this paper. The process analysis and design are based on our own experimental data (kinetics), information from open literature, and own mathematical models and computer programs for process simulation and evaluation. Reactive distillation and a tubular reactor followed by separation of components from the reaction mixture were considered and evaluated. An economic analysis indicated that operational costs dominate over the capital ones in the costs estimation and that the integration of partial processes into one vessel (reactive distillation) is advantageous. However, according to the analysis of the process conditions (temperature and pressure) for the reaction and distillation, it is impossible to execute the process in one vessel. Therefore, a fixed bed reactor combined with distillation was proposed and the technology has been developed.

Operational Behaviour of an Industrial Fixed Bed Reactor for Biomethanation of Alcohol Slops from Different Crops

1990 ◽  
Vol 22 (1-2) ◽  
pp. 385-394 ◽  
Author(s):  
P. Weiland ◽  
H. Thomsen
Keyword(s):  
Fixed Bed ◽  
High Strength ◽  
Pilot Scale ◽  
Anaerobic Treatment ◽  
Fixed Bed Reactor ◽  
Two Phase ◽  
Fixed Bed Reactors ◽  
Industrial Unit ◽  
One Year ◽  
Better Than

Distillery slops from a multicrop ethanol plant are difficult to treat anaerobically, because the composition and load changes throughout the year due to processing of different sugar-and starch-containing crops. For achieving high COD removal efficiencies and good process stabilities at medium strength loading rates, a two-phase anaerobic treatment process with a fixed-bed reactor for biomethanation was developed and tested in pilot-scale. On the basis of these experiments a full-scale unit with 1,800 m3 reactor volume was erected, which has been in operation for more than one year. The fixed-bed reactor is operated with COD loads up to 10 kg COD/m3d at hydraulic retention times of about 5 days. A variety of highly concentrated slops can be treated successfully with COD removals from 85 % to over 90 %. The fixed-bed reactor withstood sudden changes in wastewater strength and composition and is able to handle hydraulic overloads. Operational data from the industrial unit show that the performance and reliability of the fixed-bed reactor is much better than a conventional contact system, which was operated in a parallel run in the same scale. The results show, that the application of fixed-bed reactors can be recommended for a wide variety of high-strength wastewaters with low suspended solids contents.

Treatment of photographic processing wastewater using anaerobic-aerobic biofilm reactor

1997 ◽  
Vol 36 (12) ◽  
pp. 91-99 ◽  
Author(s):  
Akira Hirata ◽  
Haeng-Seog Lee ◽  
Satoshi Tsuneda ◽  
Tomotake Takai
Keyword(s):  
Fixed Bed ◽  
Biofilm Reactor ◽  
Fixed Bed Reactor ◽  
Two Phase ◽  
Effective Microorganisms ◽  
Biological Activated Carbon ◽  
Sewage Discharge ◽  
Control Value ◽  
Biofilm Reactors ◽  
Bod Removal

Two types of anaerobic-aerobic biofilm processes were applied to the treatment of the photographic processing wastewater. Two-phase fixed bed reactor packed with sponge cubic media and completely mixing three-phase fluidized bed reactor, respectively, were used as an anaerobic and aerobic biofilm reactors. One of the aerobic biofilm reactors was packed with cement balls (CB) made by crushed cement particles, and another packed with biological activated carbon (BAC). The fivefold diluted photographic processing wastewater, from which Ag had been removed previously, was used as an influent (BOD 5,700 g/m3, CODcr 17,000 g/m3, T-N 2,600 g/m3). During long-term continuous biological treatment, BOD values in effluent decreased gradually and reached 280 g/m3, which could fulfill the sewage discharge control value in Japan (BOD < 600 g/m3). It took more than one year to acclimatize the sludge and to get the effective microorganisms for degrading the compounds in the photographic processing wastewater. However, pH values in the aerobic biofilm reactors fell down to 3∼4. This was possibly because thiosulfate (5,700 g/m3) in the photographic processing wastewater was almost oxidized to sulfate by sulfur-oxidizing bacteria. For the purpose of obtaining higher BOD removal efficiency, pH in the aerobic biofilm reactor was adjusted to 7 using pH controller. As a result, BOD removal ratio was gradually improved, and the sewage discharge control value was steadily achieved after 181 days. The number of bacteria in the anaerobic biofilm reactor and the aerobic biofilm reactor with pH controller were 6.0×109 N/mL and 1.1×108 N/mL, respectively.

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