Flexible Routes to Liquid Fuels from CO2 by Advanced Catalysis and Engineering

There is an urgent need to address the accelerating increase in global CO2 emissions and atmospheric CO2 levels while providing fuels to meet growing energy needs. The UK government has targeted an 80% reduction in emissions (from 1990 levels) by 2050 with an interim target of 34% reduction by 2020. Increasingly, it is becoming clear that a key approach to storage of variable sustainable energy sources such as solar or wind power is in the form of stored chemical energy, and that this is likely to be as a form of hydrogen. However, although hydrogen itself has excellent enthalpy content per unit weight, it is a low density gas, has storage difficulties, and requires relatively high compression energy. The present proposal is focused on the conversion of sustainably produced hydrogen to high energy density liquid fuels including methanol, DME and hydrocarbons which are more easily transported and are compatible with existing fuel distribution networks. These fuels are low in sulfur and flexible in their contribution to future low carbon-intensity fuel scenarios by displacing fossil sources from the liquid fuels pool. They can be used for transport fuels (where they are likely to remain the focus for some time to come), as blending components, as seasonal storage candidates (exploiting their permanence and energy density), for distributed power production or for local heating.

The synthesis of these liquid fuels will be achieved using CO2 as a vector to react with hydrogen from solar or wind inputs. We therefore aim to develop new technology to reduce the atmospheric CO2 burden by utilising only water as a source of this hydrogen, avoiding highly endothermic thermocatalytic steam reforming. The annual CO2 emissions from UK electricity generation (around 150x10^6 tonnes) is sufficient, in principle, to supply the UK requirement for liquid transportation fuels, or three times the amount required for the world annual production of methanol (around 45x10^6 tonnes). There are a number of possible attractive concentrated point sources of this CO2, including CO2 prepared for sequestration or from ammonia plants, which could be used to make liquid fuels in the medium term provided efficient catalytic technologies could be developed. Thus we will develop new catalytic technology for the production of synthesis gas (CO/H2) and simple fuel organics, ultimately driven by solar energy using CO2 and H2 sustainably produced from water. We will explore integration of hydrogen and syngas generation with production of syngas from biogenic sources such as waste or biomass to provide additional feed flexibility. Part of our work will develop novel and targeted catalysts for the thermocatalytic production of 'green' fuels from syngas with variable CO2, H2 and water content, focused by process systems engineering considerations that specifically address low-carbon aspects such as intermittency of primary renewable power in process design. Industry partners have endorsed the approach and will provide key input into the form of point source CO2 supply, catalyst manufacture, liquid fuel synthesis, electrolyser manufacture, sustainable hydrogen generation and technology integration, life cycle analysis and industrial fuel usage.

The proposal adopts a multidisciplinary catalyst discovery, deployment and process engineering approach to develop, evaluate and optimise thermal, photo- and electro-catalysed routes to liquid fuels from CO2 and water using solar energy (and, indirectly, wind or marine power). Direct thermal and solar-assisted paths to methanol and DME will be compared with stepwise solar/electrochemical syngas generation plus thermal DME or Fischer-Tropsch hydrocarbon synthesis paths. The novel catalyst chemistries enabling each route will be integrated on the basis of process systems modelling and analysis to identify optimised schemes that will be benchmarked by input from industry partners with key roles in potential supply chains.

The main benefit is creation of value from CO2 by upgrading with renewable hydrogen to versatile liquid fuels with reduced carbon intensity, thereby reducing our dependence on primary fossil fuel resources and enhancing sustainability.

The benefits across many industrial sectors including transport, energy generation, manufacturing and chemical industries are reflected in the range of industrial partners and supporters of the project. The new catalytic processes address conversion of CO2 emissions to drop-in replacement hydrocarbon fuels that can use existing capital infrastructure and distribution networks, integration with renewable feedstock markets including renewable hydrogen generation essential for this CO2 valorisation, catalyst development and manufacture and new prospects in process engineering and systems integration including reducing the carbon footprint of the notoriously high impact construction sector and other manufacturing activity. The Decarbonisation and Energy Efficiency Roadmaps (March 2015) set out by DECC and BIS for the eight most heat-intensive industrial sectors to reduce greenhouse gas emissions and improve energy efficiency by 2050 recognises the importance of research in enabling technology options and removing barriers. This project will deliver benefits by loading the development pipeline for technology options based on catalysis science and process engineering as candidates for scale up and demonstration. Our industry partners have a track record of developing research-based technology platforms via public-private partnerships, which dramatically increases the chances of success in the long term. The influence of our industry partners across supply chains in, for example, the built environment, will accelerate the adoption of successful technologies and therefore the number and scope of business beneficiaries. In addition, each industry partner has a significant UK presence and will directly benefit from the research outcomes. These benefits include manufacturing and sales of new catalysts, hydrogen electrolysers, fuels and reduction of manufacturing costs. The University partners have significant experience in generating and protecting intellectual property from multi-partner projects, and transferring this to UK industry. These benefits all arise from the multidisciplinary approach to flexible routes to low carbon-intensity fuels taken by the project consortium.

Society will benefit from increased security of energy supply, and from reduced CO2 emissions. The proposal also offers the prospect of lower overall fuel costs for transportation, households and industry. This will improve the competitiveness of UK manufacturing in global markets, especially where commoditisation (and therefore margin erosion) has occurred, resulting in greater productivity, job creation and a better standard of living. Society will additionally benefit from jobs created in new technologies, and from the high quality researchers (RAs and associated PhD students) with a multidisciplinary skill set emerging from the project. This makes them highly valued in academia, industrial research and technical consultancies, and helps build critical mass in CO2 valorisation and low carbon technologies for the future.

The proposed research is ideally placed to inform DECC and Innovate UK policy and the activity of the main regulator the Environment Agency, and also seed translational activity of promising technologies through establishments such as the UKCCSRC Pilot-Scale Advanced CO2-Capture Technology facilities by CO2 valorisation. This policymaker engagement is further facilitated by the role of our project partners in government advisory bodies such as the Green Construction Board and the Low Carbon Innovation Group, and our connectivity to the Knowledge Transfer Network via the Knowledge Centre for Materials Chemistry.