摘要:

AbstractKinetics of hydration of propylene oxide using an ion‐exchange resin catalyst in a slurry reactor was studied. The kinetics of homogeneous, uncatalyzed reaction was studied separately and used to obtain heterogeneous reaction kinetics. The homogeneous reaction was found to be 0.43 order with respect to propylene oxide concentration. The heterogeneous reaction was found to have intraparticle diffusional resistance under certain conditions. The intrinsic kinetic parameters and effective diffusivity were obtained from these data. The heterogeneous reaction was found to be 0.55 order with respect to propylene oxide concentration. The activation energies obtained for homogeneous and heterogeneous reactions were 51.5 and 53.4 kJ/mol, respectively. A theoretical model incorporating all the mass transfer resistances has been propose

ISSN:0001-1541    

DOI:10.1002/aic.690300102

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractThe potential energy between two interacting colloidal particles is derived by a knowledge of the energy of interaction of two parallel flat plates. The proposed method maps pairs of infinitesimal surface elements from the two interacting bodies to parallel plate‐like elements. The results obtained from this theory are compared with the Derjaquin approximation for largekRand the Levine and Dube approximation for smallk

ISSN:0001-1541    

DOI:10.1002/aic.690300103

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractCalculations for nonequilibrium stages were systematized via material balances for multicomponent mixing, which is applicable in the absence of sorption.The resulting treatment is quite complex with unequal stages but much simpler when the stages are equal. It allows solving complex solid/liquid washing problems from experimental simple washing data obtained with solute‐free wash liquo

ISSN:0001-1541    

DOI:10.1002/aic.690300104

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractA heterogeneous model is developed to account for noncatalytic gas‐solid reactions in a vertical pneumatic transport reactor. The model takes into consideration both the positive and negative variations of the solid porosity and the variation of the gas diffusivity with the reaction. The method of lines utilizing the second order centered finite difference scheme for the spatial discretization is employed to obtain the model solution.Experiments utilizing a vertical pneumatic transport reactor of a laboratory scale are performed to study the reaction between limestone and sulfur dioxide generated from coal combustion. The reactor is of 16.2 cm ID and 610 cm in length. The experimental data for sulfur retention are reported for various superficial gas velocities and calcium‐sulfur molar ratios. Verification of the model with experimental data is conducted. The agreement between the model prediction and experimental data is satisfact

ISSN:0001-1541    

DOI:10.1002/aic.690300105

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractAn integral method including the entrainment hypothesis of Hoult, Fay and Forney (1969) is used to predict the concentration of product formed in a buoyant jet in a crossflow. The analysis is restricted to a slow, irreversible, second‐order reaction with premixed reactants. Reliable laboratory data are presented for the oxidation of nitric oxide by the reaction 2NO + O2→ 2NO2with excess O2and these results are correlated with the theory. Additional measurements are recorded to provide information on the magnitude of the turbulent parameters necessary for proper closure of the rate expressi

ISSN:0001-1541    

DOI:10.1002/aic.690300106

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractThe bubble formation process at small, single, circular orifices at low gas flow rates is modified when the system is vertically vibrated in a sinusoidal fashion.For systems with significant gas chamber volume, bubble volume in the vibrated case is smaller than in the nonvibrated case. The vibrations increase the amount of liquid weeping through the orifice into the gas chamber. A simple inviscid model adequately predicts bubble formation in the medium‐chamber‐volume region at low values of amplitude and frequency of vibration and low viscosities. The boundaries of the transition from theFR≫ 1 to theFR= 1 regions are described in terms of “the acceleration number/Eötvö

ISSN:0001-1541    

DOI:10.1002/aic.690300107

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractThe performance of spherical catalyst pellets with radially nonuniform distributions of activity is simulated under parallel reaction networks closely resembling hydrocarbon oxidation reactions. Both reaction paths are assumed to be exothermic with the desired path exhibiting lower activation energy requirements than the undesired one. It is shown that nonuniform activity distributions enhance effectiveness and selectivity over a large range of values of the Thiele modulus. Multiple steady states in effectiveness and selectivity are observed for certain values of the heat of reaction parameter.

ISSN:0001-1541    

DOI:10.1002/aic.690300108

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractIntermediate phases and reactions occurring on decomposing diammonium hydrogen phosphate, ammonium para molybdate, sodium tungstate dihydrate and ammonium meta vanadate were established by thermal analysis and X‐ray examination.These salts promote fabric degradation at low temperatures but are effective at high temperatures. Diammonium hydrogen phosphate produced maximum amount of gases, absorbed the highest amount of heat and gave the highest fire retardation above 350

ISSN:0001-1541    

DOI:10.1002/aic.690300109

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractRate studies are reported of the effect of rehydration‐dehydration cycling on the vapor hydration behavior of solid K2CO3. Isothermal rate data were obtained at different temperatures and water vapor pressures for the reaction of narrowlysized anhydrous particles. Effects of different particle preparation histories on the rehydration rate were investigated and correlations of rate with particle pore structure explored. Rehydration rates of dehydrated K2CO3·3/2H2O were found to depend on the conditions of the prior dehydration. Rehydration is comparatively very slow at relative pressures belowP/Peq≃ 1.5; rates increase linearly with pressure aboveP/Peq≃ 3. Hydration rates of K2CO3particles obtained as anhydrous are substantially slower than those of identically‐sized crystals produced by prior dehydration of K2CO3·3/2H2O; after one rehydration‐dehydration cycle, rehydration rates are increased by as much as two orders of magnitude and this distinction between sources virtually disappears. Diffusional resistances based on calculated water vapor diffusivities are qualitatively consistent with the observed effects of cycling but do not by themselves account fully for the o

ISSN:0001-1541    

DOI:10.1002/aic.690300110

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY

摘要:

AbstractHydrogen sulfide is oxidized to elemental sulfur by ferric ion chelated with nitrilotriacetic acid (NTA) in aqueous solution at pH 3.5 to 4.5. The reaction appears to be fast relative to gas‐ and liquid‐phase diffusion, and the transfer of H2S from a gas stream is correlated well by the theory of absorption with instantaneous chemical reaction. The ferrous ion formed in this reaction may be reoxidized with oxygen absorbed from a stream of air. The presence of NTA catalyzes the reaction of O2and Fe2+in the same pH range, and diffusion is again controlling. Design calculations based on laboratory data for both absorption steps show that cocurrent gas‐liquid contactors are advantageous for achieving high reaction rates (e.g., ∼99.99% H2S removal), high gas velocities (10 to 20 m/s), low pressure drops [1 to 3 kPa (10 to 30 cm H2O)], and moderate column heights (10 t

ISSN:0001-1541    

DOI:10.1002/aic.690300111

出版商:American Institute of Chemical Engineers    

年代:1984

数据来源: WILEY