Plastics are ubiquitous in modern life, with global production of ~260 million tonnes per year and only 9 % recycled in 2019. 8.3 billion tonnes of plastic have been produced in total and predicted 12 billion tonnes in landfill or environment by 2050, taking 400 years to degrade naturally. In future, a strong growth in demand for and production of plastics is expected, whilst concerns for the greenhouse effect necessitate that carbon dioxide emissions and reliance on fossil fuels are decreased to meet legislation. Plastics can be recycled via a range of mechanical, thermal and chemical techniques, each route having advantages and disadvantages. Some chemical recycling techniques, such as glycolysis, are applicable only to particular types of polymer. Other routes, such as mechanical recycling, produce a lower grade product, whilst thermal techniques require a high energy input. Mixed waste, including halogenated polymers such as polyvinyl chloride presents a challenge, as the chlorine is a potential catalyst poison. A recycling and upgrading process is thus required that can process a range of different pyrolysis oils derived from polymers as part of a mixed waste stream, can deal with contaminants and produce a value-added product. In Catawave we aim to address the above issues and develop a robust and energy efficient process to upgrade pyrolysis liquids derived from a range of plastic waste streams. To do this we bring together several novel requisite technologies, which will include the development of bespoke catalysts to effectively upgrade the pyrolysis oils. These will be formulated from industrial metal processing or mining waste by-products such as 'red mud' and known hydrocarbon cracking catalysts such as zeolite ZSM-5, and select samples will incorporate microwave susceptible carbon particles to aid their heating. We will assess whether microwave or induction heating in a flow reactor can deliver a more effective and energy efficient process compared with conventional resistive heating, in conjunction with the developed catalysts. The upgraded oil products will be characterised using a range of techniques, with aim of upgrading to increase the value of products, including upscaling to meet standards required for drop-in fuels. Fresh and spent catalyst will be characterised using a range of techniques to understand their catalytic behaviour and deactivation. The results of the experimental studies will be applied to develop a kinetic model using lumped approach comprising component groups, which would be used to inform the design and scale-up of reactors for an industrialised process. Techno-economic modelling will be developed to inform the process scalability and profitability, for example the selection of tonnage throughput, distributed or centralised processing of waste. We have engaged Project Partners from across the waste producing, recycling, fuels and process simulation sectors including Sabien Technology Plc, Halocycle, Severn Trent Green Power, Pressvess and Mitsubishi Chemical. They will provide samples of pyrolysis oil for upgrading, advise on catalyst formulations, assist with process design and economic evaluation, give technical consultation on the work plan and help setup routes to commercialisation and impact delivery as outlined in their letters of support.

The future 'Net Zero Economy' will be based on new forms of energy (e.g., renewable electricity and hydrogen), new feedstocks (sustainably sourced biological and waste materials), and a new depth of data. These changes present particular problems for the process industries (bulk and fine chemicals, food and beverages, pharmaceuticals, manufacturing, and utilities etc). To 'Engineer Net Zero' in these industries, they must undergo the most profound transformation since the industrial revolution. To accommodate these new energy types, novel feedstocks and new data, entirely new processes, process technologies and green chemical routes will have to be developed. The scale of the challenge is enormous; manufacturing alone accounts for ~10% of the total economic output of the UK (£203bn Gross Value Added) and ~7% of UK jobs (HMG, 2022). Research Challenges: The PINZ CDT will help to 'Engineer Net Zero' by developing new processes, green chemistries, and process technologies, via Research for Technology Transfer (O2) at the interfaces of process and chemical engineering, and the biological, chemical and data sciences. Our Research Themes (T) have been informed by and co-created with industry: (T1) Energy: The use of renewable electricity and hydrogen demands new ways to perform process steps (reactions, separations, heat transfer) and whole process design. (T2) Feedstocks: Sustainable feedstocks/raw materials and solvents (bio-based, carbon-neutral, waste-derived), will force the development of new process chemistry and technology. (T3) Data: The increasing quantity and quality of data (in-process, LCA, TEA) will dramatically change how we design, operate, and monitor processes. Training Challenges: Build Back Better: Our Plan for Growth (HMT, 2021), and The UK Innovation Strategy: Leading the Future by Creating It (BEIS, 2021) highlight a strategic focus on skills development, innovation, and Net Zero to transform the UK into a global science and engineering superpower. To meet these substantial challenges and maintain the UK as a technology hub and global leader in innovation in the process industries, the UK requires pioneering, innovative, and knowledgeable chemical engineers/chemists. These world-class, doctoral-level graduates will not only be required to navigate these challenges: they will need to lead the change. The PINZ CDT will create these 'Net Zero-enabled' future leaders via a nurturing, supportive and collaborative training environment, which will equip the researchers with the tools to develop, analyse, evaluate, and implement new technologies and processes during their projects and future careers. Student-Centred Training (O1) will underpin everything we do, tailoring research training both at the individual and CDT level, alongside the provision of the management, entrepreneurship, and business skills that industry demands. Throughout their training, we will facilitate peer-to-peer interactions within and across cohorts to build a community and engender a broad exchange of ideas. This is especially important when working with students from diverse academic and personal backgrounds and recognises the contribution diversity makes to a challenge on the scale of Net Zero. Delivery: PINZ will be led by the world's largest Process Intensification Group (PIG, Newcastle University), and the world-leading Green Chemistry Centre of Excellence (GCCE, University of York), leveraging >40 years of combined experience in technology transfer and >40 ongoing industrial partnerships. Only through this combination of the 'biggest and best' can the internationally leading education, training, and research needed to produce the next generation of leaders and innovators for Net Zero be realised.

For the UK to achieve net carbon neutrality by 2050, it is estimated that the mix of Greenhouse Gas Removal (GGR) technologies required will equate to ca. 35 M tonnes of carbon (MtC) p.a. Biochar can potentially make a major contribution both to this target and the adoption of farming practices described by the Committee on Climate Change (2020) to achieve a 64% reduction by 2050 in greenhouse gas emissions across agriculture, land use and peatlands by 64% from the 2017 level of 16 MtC. However, there are some significant challenges to overcome. There is limited availability of virgin wood to produce biochar and there are no large-scale production plants operating in the UK. Further, as well as economic viability and societal acceptability, there are concerns over biochar stability with initial degradation occurring over relatively short timescales. We propose to conduct the most ambitious and comprehensive demonstration programme to date involving arable and grassland, woodland, contaminated land, and where soil erosion control is required. Using over 200 tonnes of biochar, we will address uncertainties regarding the extent and scope of deployment and its stability with respect to carbon sequestration, together with quantifying effects on ecosystem services. The proposed research programme is highly inter-disciplinary, bridging engineering, geoscience, bioscience, social science and techno-economics, specifically designed to provide answers to the key challenges outlined and establish whether biochar can make a significant contribution to meet the UK's 2050 GGR target . The quantitative approach that we will adopt based on internationally leading science represents a step-change for biochar research in the UK, which has focussed primarily on agricultural benefits and not addressed the key challenges regarding carbon sequestration that are needed to reduce the uncertainty for policy development. Alternative bio-derived feedstocks that will significantly increase the production potential by >1 MtC p.a, will be identified. Two of our industrial partners, CEG and CPL operate demonstration and commercial plants, making them ideally placed to establish biochar production at scale in the UK. The extensive trials will provide a sound basis for establishing the potential for biochar deployment across agriculture, contaminated and reclaimed land and woodland, enabling regional and national scale effects to be quantified. To date, most field trials have been relatively localised and short-term. We aim to deploy char in large-scale farming and land management scenarios where the effects of 'real-world' management practices on the behaviour of char will be evaluated. Our excellent links with the farming sector, including the Agriculture and Horticulture Development Board and the National Farmers' Union, will provide the springboard to explore a wide range of stakeholder perspectives on biochar's role in GGR to aid policy development. . The Demonstrator will address concerns over environmental health and soil ecosystem service functioning and will provide the first comprehensive assessment of biochar stability in the UK and its impact on greenhouse gas soil emissions, with our international leading biological science and analytical capabilities. This will enable robust policy to be developed in which payments are based on the amount of carbon sequestered over extended timescales. Our business models will be based on our integrated life cycle and techno-economic analysis, identifying the carbon prices required to make deployment feasible and incorporating co-benefits of biochar use in agriculture. The Demonstrator will provide the Hub with all the necessary scientific, technological, environmental, economic and societal evidence to enable biochar deployment to be assessed in relation to other GGR approaches.