Kinetics of front-end acetylene hydrogenation in ethylene production
- UNS-CONICET, Bahia Blanca (Argentina). Planta Piloto de Ingenieria Quimica
The kinetics of acetylene hydrogenation in the presence of a large excess of ethylene was studied in a laboratory flow reactor. Experiments were carried out using a Pd/{alpha}-Al{sub 2}O{sub 3} commercial catalyst and a simulated cracker gas mixture (H{sub 2}/C{sub 2}H{sub 2} = 50; 60% C{sub 2}H{sub 4}; 30% H{sub 2}, and traces of CO), at varying temperature (293--393 K) and pressure (2--35 atm). Competing mechanisms for acetylene and ethylene hydrogenation were formulated and the corresponding kinetic equations derived by rate-determining step methods. A criterion based upon statistical analysis was used to discriminate between rival kinetic models. The selected equations are consistent with the adsorption of C{sub 2}H{sub 2} and C{sub 2}H{sub 4} in the same active sites followed by reaction with adsorbed hydrogen atoms to form C{sub 2}H{sub 4} and C{sub 2}H{sub 6} in a one-step process. Good agreement between computed and experimental results was obtained using a nonisothermal reactor model that takes into account the existence of external temperature and concentration gradients. The derived kinetic equations together with a pseudohomogeneous model of an integral adiabatic flow reactor were employed to simulate the conversion and the temperature profiles for a commercial hydrogenation unit.
- OSTI ID:
- 253748
- Journal Information:
- Industrial and Engineering Chemistry Research, Vol. 35, Issue 5; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
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