Design and optimization of fixed-bed reactor for ethylene epoxidation based on reaction kinetics
摘要
In this work, process simulation of the ethylene oxidation reaction was carried out based on the hollow four-lobed catalyst. Applicable macrokinetic models were selected through comparison with industrial data, and reactor configuration and reaction conditions were optimized by combining detailed reaction kinetic models. Among them, the effects of changes in reactor configuration on selectivity and axial temperature of the reactor were analyzed; meanwhile, the effects of changing operating conditions on reaction selectivity and axial temperature of the reactor were also explored. The results show that: (1) With the increase of reactor inlet temperature, the bed temperature rises, which has a certain inhibitory effect on reaction selectivity; (2) With the increase of the concentrations of ethylene and oxygen in the feed gas inlet components, the bed temperature slightly increases, and the ethylene oxide (EO) selectivity increases. The increase of C2H4 content has a certain promoting effect on the main reaction, while the increase of O2 content has a promoting effect on the side reactions; (3) With the increase of pressure, the bed temperature rises to promote the main reaction, and the EO selectivity increases; (4) The increase of tube diameter will lead to heat accumulation in the reactor, resulting in a decrease in reaction selectivity and an increase in bed temperature. The tube diameter was optimized according to conditions such as selectivity and reactor thermal stability, and the reactor tube diameter corresponding to the catalyst should be controlled between 33.6 and 38.3 mm.