摘要:

AbstractA non‐isothermal, non‐adiabatic fixed‐bed pilot reactor specially designed for fast measurement of axial and radial temperature and concentration profiles during dynamic experiments is described. The pilot plant is interfaced to a process computer and facilitates conducting different types of dynamic experiments, such as those with simultaneous un‐correlated periodic changes of the process variables. This type of dynamic experiments proved to be most efficient for collecting the data necessary for reactor modelling. Axial and radial temperature and concentration profiles in the fixed bed were measured during catalytic hydrogenation of toluene on an industrial nickel catalyst. Peak shaped perturbations were employed to study the parametric sensitivity of the reactor behaviour and to estimate the reaction k

ISSN:0008-4034    

DOI:10.1002/cjce.5450630122

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractData collected with forced uncorrelated sinusoidal changes of the process variables are used to simulate the behaviour of a non‐isothermal non‐adiabatic pilot plant fixed‐bed reactor. The test reaction applied is the hydrogenation of toluene to methylcyclohexane on an industrial nickel catalyst. A pseudo‐homogeneous two‐dimensional model as well as a one‐dimensional model are applied to describe the reactor behaviour. The model parameters are estimated by defining an objective function based upon residuals of the discretized differential equations instead of upon deviation from the observed variables. This procedure leads to a drastic reduction of computer expenditure. Measured and simulated temperature and concentration profiles are compared on the basis of a number of plots and fitting quality criteria. The model parameters estimated from data collected during dynamic runs are comparable to those obtained from a series of stationary experiments (23experimental design). However, with the dynamic experiments the data necessary for modelling can be collected much more

ISSN:0008-4034    

DOI:10.1002/cjce.5450630123

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractLa simulation mathématique de la circulation de I'air et du profil de température dans une enceinte rectangulaire avec plusieurs ouvertures et sources chaudes localisées a été réalisée sur ordinateurs. Une méthode numérique aux différenccs finies, combinée à un modéle simple de turbulence, a été utilisée pour réksoudre les équations différentielles de la conservation de la masse, de la quantité de mouvement et de I'énergie. Les calculs ont été effectués un nombre de Prandtl de 0.7, un nombre d'Archiméde d'environ 34 et le nombre de Grashof a atteint des valeurs de I'ordre de 3 × 109. Une comparaison entre les résultats numériques et ceux observés dans une maquette permet de conclure que le modtèle mathématique reproduit assez fidètlement I'écoulement de I'air et le profil de température.L'effet combiné de la convection naturelle au voisinage des sources chaudes et de la convection forcée engendre une circulation complexe dans I'enceinte. Ces conditions d'opération ont été choisies dans le but d'Ctudier les conditions de la circulation de I'air et de la température dans les salle

ISSN:0008-4034    

DOI:10.1002/cjce.5450630124

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractSeveral inorganic reducing agents of various chemical characteristics have been tested to see if they reduce the oxygen contained in coal. It was found that oxygen content of coals decreased when they were heated in only water (blank runs). The treatment with the reducing agents containing sulphur did not increase the oxygen removal over that achieved in the blank runs. However, it appears that the ferrous salt catalytically deoxygenated both the lignite and bituminous coals.

ISSN:0008-4034    

DOI:10.1002/cjce.5450630125

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractResults are reported on the influence of intraparticle diffusion on the measured rate of reaction under a condition where the feed composition is changing periodically. The specific application is to cyclic operation of an ammonia synthesis reactor.The effectiveness factor calculated relative to the steady‐state kinetic rates for the time‐average feed condition for fine particles was higher than the comparable steady‐state effectiveness factor as a result of the rate improvement due to cycling.The effectiveness factor calculated relative to the time‐average rate of reaction under cyclic operation for the fine particles was much less than unity and similar numerically to the steady‐state effectiveness factor. The cycling effectiveness factor by either definition varied with cycling conditions because of the complex interaction of cycling p

ISSN:0008-4034    

DOI:10.1002/cjce.5450630126

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractA new model is proposed on the basis of the simultaneous decrease of build‐up yield stress and viscosity to describe the break down of crude oil gel. A set of two experiments conducted at different but under constant wall shear stress is required to compute the four parameters of the model. The model is verified with reported dat

ISSN:0008-4034    

DOI:10.1002/cjce.5450630127

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe effect of liquid viscosity on gas holdup in a 15.1 mm diameter vertical pipe was assessed over the viscosity range 0.00092‐1.670Ns m‐2. Gas holdup increased with increased liquid viscosity. The sensitivity of holdup to changes in viscosity was slight at low viscosity but was markedly increased at higher viscosities.Gas holdup was found to be well described, over the viscosity range studied, by the empirical equation:\documentclass{article}\pagestyle{empty}\begin{document}$$ \[ \varepsilon /(1 - \varepsilon )^4 = 10.62\exp (1.49\mu _L )U_g\] $$\end{docum

ISSN:0008-4034    

DOI:10.1002/cjce.5450630128

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0008-4034    

DOI:10.1002/cjce.5450630101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY