Multi-Scale Reaction Modelling: A Route to a Sustainable Future?

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A shift towards greener and more sustainable manufacturing methods by chemical and pharmaceutical industries is leading to increased implementation of flow processes. These flow processes allow for more flexible and continuous production of a more diverse range of chemical targets. The development of new flow reactors has allowed photo- and electrochemistry to be more widely accessible, allowing for more energy and atom efficient routes for complex chemical syntheses. Modular flow systems allow for the safer use of hazardous chemicals and harsher conditions so greatly expand the process window. When combined with PAT for continuous monitoring there is great opportunity for reaction automation and self-optimisation. When combined with computational modelling, this continuous monitoring will allow for more effective use of the acquired data leading to rapid realization of optimal operating conditions. Creating computational models of chemical systems is increasingly being used by manufacturing companies to make predictions on how their process is operating. Previously, modelling has mainly been used on an industrial scale, however, due to the shift towards smaller scale processes it is necessary to understand the characteristics of reactors on the kilo- and lab scales. Modelling programmes such as gPROMS are purpose built to model chemical production processes. Whilst gPROMS gives good predictions on full processes it has limited predictions down to small scale laboratory reactors. Computational Fluid Dynamics (CFD) has widely been used in the aerospace and automotive industries to visualise fluid flow, recently this has also been applied to manufacturing processes visualising flow within reactors. Understanding the fluid flow within reactors, combined with reaction kinetics, is essential for estimating changes required in the scale up of production processes. The prediction of this scale-up and the ability to quickly establish the optimal process parameters will vastly improve the sustainability and efficiency by ensuring minimal waste in both reagents and energy. The goal of this project is to create tailored models to specific chemical products to facilitate the scale-up of flow reaction systems. This will be done using CFD to optimise reactor design and gPROMS to optimise for operating conditions. The combination of these two methods will allow for quick and easy optimisation of multi-step processes from laboratory to industrial scale. The starting point will be the scale-up of the electro-vortex reactor recently developed at Nottingham, which uses a rotating cylinder inside a static outer cylinder to create Taylor-Couette vortices within the gap between the two cylinders. These vortices de-couple the mixing of reactants from residence time and the reactor has been successfully used for multi-mole per day methoxylation of N-formylpyrrolidine. The first step is to scale-up the production of this from 0.5kg/day to around 20kg/day. This will be tackled by CFD modelling to adapt the reactor design for this larger scale production particularly to investigate the effects of the large volumes of H2 that will be generated. After establishing the optimal reactor design, gPROMS will be used to establish optimal operating conditions within telescoped reactor systems involving the electro-vortex. This can then be expanded to optimising other vortex reactor designs for compound specific reactions.