화학공학소재연구정보센터
Industrial & Engineering Chemistry Research, Vol.48, No.3, 1090-1095, 2009
Simulation of a Membrane Reactor for the Catalytic Oxidehydrogenation of Ethane
Industrial-scale ethylene production using a novel membrane multitubular reactor for the ethane oxidative dehydrogenation process over a Ni-Nb-O catalyst is proposed. A theoretical study was performed by means of a pseudohomogeneous model of the tube and shell sides. The feasibility and convenience of using this novel design, as well as the influence of the main operating variables on the reactor performance, were analyzed. The introduction of the membrane leads to lower oxygen partial pressures inside the catalyst tubes when compared with a conventional multitubular reactor. This leads to very good ethylene selectivities, good temperature control as a result of lower heat generation rates, and reasonable production rates. The reactor performance appears to be highly affected by the balance between the rate of oxygen consumption by the chemical reaction and its rate of permeation through the membrane. Under certain operating conditions leading to lower reaction rates, an undesired accumulation of oxygen inside the tubes is observed. A minimum amount Of O-2 injected at the tube mouth appears beneficial to overcoming this accumulation phenomenon. The membrane reactor shows a nonconventional inverse parametric sensitivity with respect to the inlet temperature. When the reactor is operated at conditions where the reaction is controlled by the permeation flow Of O-2 through the membrane, it is possible to reach high selectivities to ethylene, significant ethane conversions, and mild temperature profiles.