Ethylene Epoxidation on Ag-Cs/α-Al₂O₃Catalyst:  Experimental Results and Strategy for Kinetic Parameter Determination

Abstract

The kinetics of ethylene epoxidation network were studied experimentally over a cesium-doped silver catalyst supported on α-Al2O3 pellets in a differential reactor. A variety of rate functions were considered and among these, expressions based on a dual-site Langmuir−Hinselwood mechanism: r i = k i P E /(1 + P E)2, fitted the data best with an average error of 13.0 and 10.7% for the epoxidation and the complete combustion reactions, respectively. Under the experimental conditions, both reactants influence both reaction rates; however, product influence is negligible because of their small partial pressures present in the reactor. High oxygen/ethylene ratios and lower temperature favored selectivity to the epoxidation reaction. The kinetic parameters obtained from the differential reactor experiments were refined to match the fixed-bed reactor experiments. With this, the average error in predicting both ethylene conversion and selectivity to ethylene oxide was 4.3%. The apparent activation energies for the epoxidation and combustion reactions were 60.7 and 73.2 kJ/mol, respectively.

Stability Study on Ethylene Oxide Industrial Reaction from the Management of Critical Process Variables

“…The Langmuir‐Hinshelwood reaction mechanism was fed on the simulator which considered kinetic parameters obtained from studies of Lafarga et al 23 and manipulated variables operating within normal conditions of the process.…”

Ethylene epoxidation over supported silver catalysts – influence of catalyst pretreatment on conversion and selectivity

“…It can be, however, enhanced by doping the catalysts with different promoters . The most commonly used promotors are cesium and rhenium . In fact, optimal promotor loadings can boost selectivity by almost 10% compared with unpromoted silver catalysts .…”

Real‐time optimization of a tubular reactor with distributed feed

“…The epoxidation of ethylene produces ethylene oxide, which is an important industrial chemical in the production of ethylene glycol and other chemicals. 21 The reaction scheme is generally considered to be given by the following parallel network 13,15 :…”

“…[13][14][15][16] A more specific case is the oxidation of ethylene, which is used for the simulation of the proposed controller. The objective is to maximize the fraction of the product of interest C at the reactor output.…”