Modeling and Simulation of the Process of Dehydration of Bioethanol to Ethylene

Abstract

-The use of carbon-based waste biomass in the production of plastics can partially meet the growing demand for plastics in the near future. An interest in the production of ethylene from bioethanol has been renewing, motivated mainly by environmental appeal and economics. The main objective of this work is the development of a mathematical model for simulation and optimization of the production of ethylene by the dehydration of ethanol, improving the performance of the process. The phenomenological model proposed is based on mass, momentum and energy balances for the process. The results obtained are satisfactory in comparison with theoretical results and experimental data found in the literature.

Bioethylene Production: From Reaction Kinetics to Plant Design

“…The data from the experimental study by Kagirmanova et al under isothermal conditions were reproduced first, in order to check the coherence of the new kinetic model (Figure ). Then, to align the virtual reactor outcomes to the calculation of Maia et al, the kinetic constants were reoptimized imposing the same temperature profile calculated by these latter Figure ; notice also that a similar shape of the temperature profile in lab-scale tests on alumina was reported independently in ref ). This adjustment was necessary, because a plug-flow reactor model in Aspen Plus does not consider the diffusion and thermal gradients calculated in the cited literature.…”

“…Test of the adopted kinetic model to reproduce the original data of ref (left) and the reactor’s output already calculated in ref on the basis of the same data (right).…”

“…The coupled equations are integrated, for the steady state, over the reactor length x by an embedded routine. The abovementioned laboratory data were then retro-fitted adjusting the kinetic constants of the reaction rates but keeping the activation energies fixed; a similar analysis was already carried out by Maia et al, 50 though a direct comparison of the parameters cannot be done because these authors employed a nonisothermal model with diffusive corrections. However, the reported stoichiometry was extended to consider possible byproducts coming from reforming, like parasitic reactions (also observed using acidic oxides), 9,25,51 again adjusting the kinetic pre-exponential factors to comply with known data, 25…”

“…The coupled equations are integrated, for the steady state, over the reactor length x by an embedded routine. The above-mentioned laboratory data were then retro-fitted adjusting the kinetic constants of the reaction rates but keeping the activation energies fixed; a similar analysis was already carried out by Maia et al, though a direct comparison of the parameters cannot be done because these authors employed a nonisothermal model with diffusive corrections.…”

Modeling of Catalyst Deactivation in Bioethanol Dehydration Reactor

“…The reaction rate model for each reaction is based on the previous work of Maia et al, , which follows the mass action law and considers the reversibility of the reactions. Without loss of generality, the reaction rate expression for a reaction j can be written by the following equation: …”