Tahani S. Gendy

Simulation of liquid and vapour phase xylene isomerization over deactivating H‐Y‐Zeolite

A steady-state simulation model for xylene isomerization over H-Y-Zeolite was developed. Liquid and vapour phase reactions were considered. The fixed bed catalytic reactor was simulated as a plug flow reactor that operates either isothermally or adiabatically. Four temperature levels were investigated taking into consideration catalyst deactivation. The main reactions considered in the model were the isomerization reactions and the disproportionation of xylenes to toluene and trimethylbenzene. The model predicts the concentration and temperature profiles for a given input of operating conditions. The simulation results revealed the similarity in the reactor behaviour if it operates either isothermally or adiabatically with respect to the distribution of the reaction products and catalyst deactivation. The study also indicated that performing the reaction in the liquid phase is more favourable than in the vapour phase due to better selectivity, relative productivity, efficiency and approach to equilibrium.

Response surface methodology for carbon dioxide reforming of natural gas

ABSTRACT The performance of 0.5% wt Rh/γ-AL2O3 catalyst for the dry reforming of natural gas using carbon dioxide has been studied. The response surface methodology (RSM) is used to study the effect of two different operating parameters, namely the hourly space velocity at the levels 18,000, 36,000, 45,000, and 60,000 ccg−1 h−1 and the reaction temperature at the levels 600, 700, and 800°C, on the conversion of the different components comprising commercial natural gas. The RSM is used to illustrate such effect in the three dimensions and shows the location of the optimum for the conversion or production of each component.

Comparative assessment of response surface methodology quadratic models and artificial neural network method for dry reforming of natural gas

ABSTRACT The performance of 0.5% wt Rh/γ-AL2O3catalyst for the dry reforming of natural gas using carbon dioxide has been considered. In the present work a comparative study has been performed using Radial Basis Function Neural Network (RBFNN) and Response Surface Methodology (RSM) quadratic models to investigate their predictive ability for the effect of two different operating parameters, naSSSmely the hourly space velocity and the reaction temperature on the conversion of the different components comprising commercial natural gas. The predictive capabilities of the two methodologies were compared employing statistical error functions. The results indicated the superiority of RBF in the prediction capability; for example, the F-ratio for the CH4 reactant is 86 and 1088185 employing RSM and ANN methods, respectively. Also for the various components involved in the reaction system R2 ranges from 0.74 to 0.96 in case of RSM while it is 1.0 for all components employing ANN. This is due to ANN ability to approximate the non-linearity between the input and output variables.

Heat-exchanger networks synthesis with fuzzy inlet temperatures using linear membership function and analytic hierarchy process

Heat exchanger network synthesis with uncertain source-stream temperatures has been formulated as a fuzzy multi-objective mixed-integer nonlinear programming problem (F-MO-MINLP) to handle the multiple objectives of minimum utility consumption, minimum total area, and even minimum number of matches. Inlet Temperatures are proposed as fuzzy variables. The linear (Triangular) membership function has been employed to describe this variation of Inlet Temperatures at different α-cut values. The effect of variation of the α-cut values on the various objectives has been investigated. The Analytic Hierarchy Process (AHP) has been utilized to obtain the weights of objectives. Two examples are presented to demonstrate the various aspects dealt in the work.