Stirred Flow Reactor Research Articles

Kinetic study of 1-butene oxidation in a jet-stirred flow reactor

An analytical study of the oxidation of 1-butene in a jet stirred flow reactor is presented. The experiments were conducted in the temperature range 900–1200 K at pressures extending from 1 to 10 atm for a wide range of fuel-oxygen equivalence ratios (0.15 to 4.0). The concentrations of molecular species were measured at different extents of reaction by gas chromatography. The main hydrocarbon intermediates were ethylene, propene, methane, 1–3 butadiene and ethane. Several other unsaturated hydrocarbons were also detected as minor products, among them cis and trans 2-butenes. A chemical kinetic reaction mechanism developed previously and extended to reproduce the experimental data is detailed, and the main reaction sequences are discussed. However, several aspects of the mechanism remain not well characterised. Among them, the reactions consuming 1-butene are essential for the development of the reaction process. The presence of 1,3-butadiene in significant concentration is an interesting observation of the present experimental study. Although it is formed for a large part by reation C2H4+C2H3=C4H6+H the contribution of C4H7 reactions is important. This means that H abstraction from 1-butene is a major process removing this compound. However, addition reactions to the double bond are also invocated, and the importance of these processes is not elucidated.

ChemInform Abstract: Experimental Study and Kinetic Modeling of Propene Oxidation in a Jet Stirred Flow Reactor

ChemInformVolume 19, Issue 22 Preparative Organic Chemistry ChemInform Abstract: Experimental Study and Kinetic Modeling of Propene Oxidation in a Jet Stirred Flow Reactor P. DAGAUT, P. DAGAUT Cent. Rech. Chim. Combust. Hautes Temp., CNRS, 45071 Orleans, Fr.Search for more papers by this authorM. CATHONNET, M. CATHONNET Cent. Rech. Chim. Combust. Hautes Temp., CNRS, 45071 Orleans, Fr.Search for more papers by this authorJ. C. BOETTNER, J. C. BOETTNER Cent. Rech. Chim. Combust. Hautes Temp., CNRS, 45071 Orleans, Fr.Search for more papers by this author P. DAGAUT, P. DAGAUT Cent. Rech. Chim. Combust. Hautes Temp., CNRS, 45071 Orleans, Fr.Search for more papers by this authorM. CATHONNET, M. CATHONNET Cent. Rech. Chim. Combust. Hautes Temp., CNRS, 45071 Orleans, Fr.Search for more papers by this authorJ. C. BOETTNER, J. C. BOETTNER Cent. Rech. Chim. Combust. Hautes Temp., CNRS, 45071 Orleans, Fr.Search for more papers by this author First published: May 31, 1988 https://doi.org/10.1002/chin.198822124Citations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume19, Issue22May 31, 1988 RelatedInformation

Kinetic modeling of ethylene oxidation

The oxidation of ethylene was studied in a jet stirred flow reactor in the temperature range 900–1200K at pressures extending from 1 to 10 atm for a wide range of fueloxygen equivalence ratios (0.15 – 4.0). A computer program has been developed to model the experimental data using a chemical kinetic reaction mechanism. A direct method to determine the first order sensitivities of the mole fraction of each species with respect to the rate constants was used to develop the kinetic scheme. The present chemical kinetic reaction mechanism is able to reproduce our experimental results, although some discrepancies are observed for the minor products, particularly for acetylene. The validation of the present mechanism is extended to higher temperatures, in order to describe the oxidation of C 1 and C 2 hydrocarbons in shock tubes. The experimental ignition delays obtained behind reflected shock waves, by various authors, are compared with the predictions of the model. A good is found for methane in the temperature range 1200–2150K, for ethane in the temperature range 1200–1700K, and for ethylene in the temperature range 1050–1900K.

Experimental study and kinetic modeling of propene oxidation in a jet stirred flow reactor

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExperimental study and kinetic modeling of propene oxidation in a jet stirred flow reactorP. Dagaut, M. Cathonnet, and J. C. BoettnerCite this: J. Phys. Chem. 1988, 92, 3, 661–671Publication Date (Print):February 1, 1988Publication History Published online1 May 2002Published inissue 1 February 1988https://doi.org/10.1021/j100314a019RIGHTS & PERMISSIONSArticle Views279Altmetric-Citations63LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (972 KB) Get e-Alerts

Third-body interactions in the oscillatory oxidation of hydrogen in a well stirred flow reactor

Stationary and oscillatory ignition states have been studied in mixtures of hydrogen and oxygen under flowing conditions in a non-adiabatic, well stirred vessel. The conditions bridge the region between ‘slow reactions’ and ignition at the second (p–Ta) limit. An oscillatory mode of ignition is observed at the boundary; it gives way to a stable state corresponding to complete reactant consumption at higher temperatures within the ignition peninsula. The period of oscillations is governed by the composition of the reaction mixture. The effects on the period of addition of diluents (He, Ar, N2, CO, CO2 and C3F8) and changes in the H2/O2 ratio have been studied by monitoring changes in temperature and light output from the system. The global behaviour of these systems can be modelled successfully using the accepted H2/O2 reaction scheme. Comparison of model predictions and experimental findings leads to values of the third-body efficiencies of He, Ar, N2, CO, CO2 and C3F8 relative to H2 of 0.35, 0.35, 0.45, 0.40, 0.90 and 2.90, respectively, in the reaction H + O2+ M → HO2+ M. With some mixtures hysteresis and birhythmicity are observed in their oscillatory behaviour; these effects too can be modelled successfully.

Development and use of a constant flow stirred thermokinetic reactor (steady-state TKR)

In addition to studies of reaction kinetics by a transient method in a batch reactor (nonsteady-state), such studies should also be carried out by continuous operation in a stirred-flow reactor (steady-state). Only in this way, for instance, can the extent be recognized to which the simplifying assumptions often made in the evaluation of industrial kinetics from transient investigation are reasonable and whether the kinetics obtained are applicable to complex reactor design. The thermokinetic reactor (TKR), with which it has only been possible to measure the rate of heat evolution in experiments under transient conditions (batch TKR), has now been modified so that investigations can also be carried out in the stirred-flow manner (steady-state TKR).

Complex periodic oscillations and Farey arithmetic in the Belousov–Zhabotinskii reaction

Our experiments on the manganese-catalyzed Belousov–Zhabotinskii reaction in a stirred flow reactor reveal many sequences of distinct multipeaked periodic states. In the parameter ranges studied the waveform for each periodic state consists of an admixture of small and large amplitude oscillations. No chaos is discernible, and in many cases the transitions from one periodic state to another occur without any observable hysteresis. Two types of sequences were studied in detail, one with waveforms consisting of concatenations of two basic patterns and another with waveforms consisting of concatenations of three basic patterns. The sequences of states with two patterns are described well by Farey arithmetic, which provides rational approximations of irrational numbers. These states can be characterized by a firing number, the ratio of the number of small amplitude oscillations to the total number of oscillations per period. For our data this ratio is a monotone stepwise-increasing function of flow rate, and the steps have a fractal dimension. The relationship between the observed sequence and the Farey arithmetic and the observation of a fractal dimension for the steps in the firing number suggest that the states formed by concatenating two patterns can be interpreted in terms of frequency locking on a 2 torus in phase space. The sequences of states with three basic patterns are described by a generalized Farey arithmetic that provides rational approximations for pairs of irrational numbers that are mutually irrational; this suggests that these states can be interpreted in terms of frequency locking on a 3 torus. A piecewise-linear two-dimensional map is shown to yield a phase diagram in qualitative accord with the measured phase diagram for these sequences.

ChemInform Abstract: Kinetic and Product Studies of the Thermal Decomposition of Dimethylsilane in a Single‐Pulse Shock Tube and in a Stirred Flow Reactor.

Chemischer InformationsdienstVolume 17, Issue 24 Preparative Organic Chemistry ChemInform Abstract: Kinetic and Product Studies of the Thermal Decomposition of Dimethylsilane in a Single-Pulse Shock Tube and in a Stirred Flow Reactor. S. F. RICKBORN, S. F. RICKBORNSearch for more papers by this authorD. S. ROGERS, D. S. ROGERSSearch for more papers by this authorM. A. RING, M. A. RINGSearch for more papers by this authorH. E. O'NEAL, H. E. O'NEALSearch for more papers by this author S. F. RICKBORN, S. F. RICKBORNSearch for more papers by this authorD. S. ROGERS, D. S. ROGERSSearch for more papers by this authorM. A. RING, M. A. RINGSearch for more papers by this authorH. E. O'NEAL, H. E. O'NEALSearch for more papers by this author First published: June 17, 1986 https://doi.org/10.1002/chin.198624091AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume17, Issue24June 17, 1986 RelatedInformation

Dynamics of n-heptane and i-octane combustion processes in a jet stirred flow reactor operated under pressure

Dynamics of combustion processes of n-heptane and i-octane have been studied with varying temperature and pressure by means of a jet stirred flow reactor (JSFR), in the range 450–850K and 1 – 12 atm. Periodic or damped oscillatory cool flames, multistage ignitions, “jumps,” and slow combustion have been observed, and their regions of existence in the pressure/temperature plane have been mapped. Results indicate that ignition of n-heptane is possible at low temperatures and it is not strongly dependent on pressure. The behavior observed with i-octane at low temperatures is strongly dependent on pressure and give rise to ignition at pressures above ∼8 atm. At high temperature, spontaneous ignition occurs in both hydrocarbons and at pressures above ∼4 atm is feebly dependent on pressure.

Multiplicity in a chemical reaction with one-dimensional dynamics.

Measurements on the Belousov-Zhabotinskii reaction in a stirred flow reactor reveal, beyond a period-doubling cascade, a sequence of periodic states that is different from the "U (universal) sequence" found in recent experiments on diverse systems. Particular periodic states occur in three different parameter ranges rather than one range as in the U sequence. However, the order of periodic states found here is in accord with a one-dimensional single-parameter map constructed from the laboratory data.

Simple Models for Diaphragm‐Type Chlorine/Caustic Cells: I . Dynamic Behavior

A simple model of the dynamic behavior of a diaphragm‐type chlorine/caustic cell is presented. The model is based upon measurable diaphragm properties and the mass transfer of hydroxyl ion through the diaphragm. The anolyte is modeled simply as a region in which the OH− ion concentration is fixed, the diaphragm is modeled as a plug‐flow reactor with an electrochemical reaction occurring at the catholyte/diaphragm interface where the cathode is placed, and the catholyte is modeled as a completely stirred flow reactor. Analytical integration of the governing equations for these models yields two mathematical expressions: one for the concentration distribution of hydroxyl ion within the diaphragm and one for the effluent concentration. Both of these expressions are functions of time, independent operating variables, diaphragm properties, and physical constants. They are used to show how the concentration distribution of OH− within the diaphragm and the cell effluent change when subjected to a step change in the current density. Also presented is a numerical method of solution for the model equations to predict the required change of the cell head subject to an arbitrary time‐dependent change in the current density at a fixed cell effluent concentration.

Kinetic and product studies of the thermal decomposition of dimethylsilane in a single-pulse shock tube and in a stirred flow reactor

Kinetic and product studies of the pyrolyses of dimethylsilane in a single-pulse shock tube (1135-1290 K) and in a stirred flow reactor (890-1000 K) are reported. The shock-induced reaction is accelerated by free-radical and silylene chains which cannot be quenched by trapping agents. The mechanisms of the pyrolyses in various temperature ranges are discussed and modeling results for the stirred flow and shock tube reactions are shown to be in reasonable agreement with experimental observations. Mechanisms for the decomposition of dimethylsilylene to ethylene and acetylene via silacyclopropane and silacyclopropene intermediates, respectively, are proposed. Arrhenius parameters for molecular elimination of methane from dimethylsilane are deduced (log k/sub CH/sub 4// = 14.8 - 73.000/2.3 RT), establishing an activation energy for CH/sub 3/SiH insertion into the (C-H) bond of methane of E similarly ordered 24.5 kcal (pressure standard state). 32 references, 1 figure, 6 tables.

Model Prediction of Entrainment Phenomena in a Stirred Flow Reactor with Limit Cycle Oscillations

Model Prediction of Entrainment Phenomena in a Stirred Flow Reactor with Limit Cycle Oscillations

Bifurcation structure of the Belousov-Zhabotinskii reaction in a stirred flow reactor

Bifurcation structure of the Belousov-Zhabotinskii reaction in a stirred flow reactor

Periodic Operation of a Stirred Flow Reactor with Limit Cycle Oscillations

AbstractThe oscillating flow reaction of bromate, bromide, and cerous ions was investigated computationally in a continuously stirred tank reactor (CSTR) where periodic perturbations were imposed on either the input rate or one of the inflow concentrations. The model computations predict a variety of interesting phenomena such as harmonic and subharmonic entrainment, chaos, transient behavior, and low amplitude harmonics. Under certain conditions the natural oscillations of the system can be considerably damped or enhanced by perturbation inputs of the proper frequency. The theoretical behavior of the system, studied under various experimental conditions, suggests many feasible experiments which are interesting in themselves, but may also serve as an additional probe of the complex mechanism used.

Experimental observations of periodic and chaotic regimes in a forced chemical oscillator

Abstract Experiments showing periodic and chaotic behavior in a Belousov-Zhabotinski (BZ) reaction mixture in a stirred flow reactor with periodic addition of bromide ions are presented. An alternating sequence of periodic and aperiodic regimes as a function of the period of Br - pulses is observed in experiments. This behavior is well described by a simple model based on the results of single-pulse experiments.

Studies of reactions of atoms in a discharge-flow stirred reactor. Part 5.—O(3P)+ trimethylamine

A discharge-flow system incorporating a stirred-flow reactor has been used to obtain stoichiometric coefficients for the rapid reaction between O(3P) and trimethylamine (TMA). The amounts of O atoms consumed and NO molecules produced when TMA was added to the stirred-flow reactor at 420 K were determined directly by measurements of chemiluminescent intensities. The yield of H atoms was estimated by a kinetic method when an excess of NO was present at relatively high pressures. On addition of CO to induce competition for OH between the reactions CO + OH → CO2+ H (4) and O + OH → O2+ H (5) the resultant decrease in O-atom consumption indicated that 5.2±1.4 OH radicals were generated per TMA molecule reacted. Reaction (5) is the only likely source of O2 from the reaction. The stoichiometric equation deduced is (14.6±0.9)O+(CH3)3N → NO+3(CO+CO2)+(7±1)H+(5.2±1.4)O2 with the likelihood that a small yield of H2 is generated also.The stoichiometric coefficient of O atoms was found to decrease by 1.2±0.3 in O+N2+CO systems when the point of addition of TMA was switched from the stirred-flow reactor to a section of the entry tubing, the times for reaction prior to observation changing from ca. 1 s (at 420 K) to ca. 15 ms (at 292 K) correspondingly. In view of the limited extent of possible reaction of formaldehyde in 15 ms this excludes formaldehyde and hence its precursor CH3 radicals from being major intermediates in the reaction. The major reactions composing the mechanism have rate constants > 109 dm3 mol–1 s–1 at 292 K.

Qualitative aspects of ethylene oxide oxidation in a well-stirred flow reactor

The slow oxidation of ethylene oxide in a stirred-flow reactor was studied, and accurate, fast-response thermocouples were used for the measurement of temperature rises due to the oxidation. The effects of mixture strength, ambient temperature and total pressure on the temperature rise are illustrated and discussed. Comparisons are made with results previously reported for ethylene oxide when studied in closed vessels.

Systematic design of chemical oscillators. 15. A new type of bromate oscillator: the bromate-iodide reaction in a stirred-flow reactor

Sustained oscillations and bistability have been observed in the reaction between bromate and iodide in acidic solution in a stirred tank reactor at 25/sup 0/C. This reaction appears to be the first bromate oscillator that requires a mechanism more analogous to that of chlorite oscillators than to that of other bromate systems such as the Belousov-Zhobotinskii reaction.

Hydroliquefaction of Australian coals with recycled slurry oil in a 1 kg h −1 continuous reactor

Coals from major Australian fields considered as suitable hydroliquefaction feedstocks were hydrogenated in a 1 kg h −1 continuous reactor unit at reaction conditions 415–435 °C and 21 MPa using a stirred flow reactor with retention time of about 2 h. The effect of coal rank and the catalytic effects of disposable iron-based (red mud plus sulphur) catalysts were studied. The system was operated continuously with process-derived recycle solvent for up to 236 h. The time for a single pass of recycle solvent was estimated to be 20 h. Distillate oil yields in the range 35–53% on daf coal were obtained under catalytic operation. The heavier product oils were shown to contain predominantly aromatics, hydroaromatics and phenolics. This indicates that fairly severe hydro-treatment would be required to produce specification diesel and aviation turbine fuels. Recycle solvent composition was observed to stabilize in 2–4 passes after making a process change. These data compare favourably with those obtained on the same coals in larger pilot plants showing that this unit is capable of producing useful yield data.