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

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.

This CDT will deliver impact aligned to the following agendas:

People
A2P will provide over 60 PhD graduates with the skill sets required to deliver innovative sustainable products and processes into the UK chemicals manufacturing industry. A2P will inspire and develop leaders who will:
- understand the needs of industrial end-users;
- embed sustainability across a range of sectors; and
- catalyse the transition to a more productive and resilient UK economy.

Economy
A2P will promote a step change towards a circular economy that embraces resilience and efficiency in terms of atoms and energy. The benefits of adopting more sustainable design principles and smarter production are clear. For example, the global production of active pharmaceutical ingredients (APIs) has been estimated at 65,000-100,000 tonnes per annum. The scale of associated waste is > 10 million tonnes per annum with a disposal cost of more than £15 billion. Consequently, even a modest efficiency increase by applying new, more sustainable chemical processes would deliver substantial economic savings and environmental wins. A2P will seek and deliver systematic gains across all sectors of the chemicals manufacturing industry. Our goals of providing cross-scale training in chemical sciences with economic and life- cycle awareness will drive uptake of sustainable best practice in UK industry, leading to improved economic competitiveness.

Knowledge
This CDT will deliver significant new knowledge in the development of more sustainable processes and products. It will integrate the philosophy of sustainability with catalysis, synthetic methodology, process engineering, and scale-up. Critical concepts such as energy/resource efficiency, life cycle analysis, recycling, and sustainability metrics will become seamlessly joined to what is considered a 'normal' approach to new molecular products. This knowledge and experience will be shared through publications, conferences and other engagement activities. A2P partners will provide efficient routes to market ensuring the efficient translation and transferal of new technologies is realised, ensuring impact is achieved.

Society
The chemistry-using industries manufacture a rich portfolio of products that are critical in maintaining a high quality of life in the UK. A2P will provide highly trained people and new knowledge to develop smarter, better products, whilst increasing the efficiency and sustainability of chemicals manufacture.
To amplify the impacts of our CDT, effective public engagement and technology transfer will become crucially important. As a general comment, 'sustainability' styled research is often regarded in a positive light by society, however, the science that underpins its effective implementation is often poorly appreciated. The University of Nottingham has developed an effective communication portfolio (with dedicated outreach staff) to tackle this issue. In addition to more traditional routes of scientific communication and dissemination, A2P will develop a portfolio of engagement and outreach activities including blogs, webpages, public outreach events, and contribution of material to our award-winning YouTube channel, www.periodicvideos.com.

A2P will build on our successful Sustainable Chemicals and Processes Industry Forum (SCIF), which will provide entry to networks with a wide range of chemical science end-users (spanning multinationals through to speciality SMEs), policy makers and regulators. We will share new scientific developments and best practice with leaders in these areas, to help realise the full impact of our CDT. Annual showcase events will provide a forum where knowledge may be disseminated to partners, we will broaden these events to include participants from thematically linked CDTs from across the UK, we will build on our track record of delivering hi-impact inter-CDT events with complementary centres hosted by the Universities of Bath and Bristol.