Design of a process for the one-pot bio-ethylene oxide production

The possibility to exploit renewable sources for the production of bulk chemicals is attractive and bio-ethanol has been recently proposed as platform to produce hydrogen via steam reforming and bio-ethylene by dehydration. Another compound with huge industrial applications is ethylene oxide, which may be in principle obtained in two steps following the route bioethanol bio-ethylene bio-ethylene oxide. Recently, a one-pot synthesis has been proposed. Based on that, the to design from the grass roots a new production plant, including the reactive and purification sections, has been developed, to exploit it industrially after checking its economic sustainability. In this work, the first step for design, i.e. kinetic modelling and reactor design, will be presented and discussed. A reaction pathway with parallel and consecutive reactions has been hypothesized and the kinetic parameters for the five reactions drawn have been retrieved by regression of experimental literature data. The model employed preliminarily is a power law pseudo-homogeneous one, used for a first sizing of the reactor and basic assessment of the technology. Three shell heat exchange reactors were implemented to control the exothermicity of the reaction, with simultaneous steam production. Three catalyst beds were used in such reactors (200, 500 and 2,000 kg) with intercooling. 99.5 % ethanol conversion and 84 % selectivity to ethylene oxide were achieved, with ca. 90 kmol/h productivity, starting from the bioethanol production of a commercial bio-refinery as preliminary criterion for sizing.