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Production of Sustainable aircraft grade Kerosene from water and air powered by Renewable Electricity, through the splitting of CO2, syngas formation and Fischer-Tropsch synthesis

Periodic Reporting for period 2 - KEROGREEN (Production of Sustainable aircraft grade Kerosene from water and air powered by Renewable Electricity, through the splitting of CO2, syngas formation and Fischer-Tropsch synthesis)

Reporting period: 2019-10-01 to 2020-09-30

KEROGREEN’s objective is to produce green synthetic jet-grade fuel based on a net-zero carbon fuel cycle, the kerosene being synthesised from air and water, powered by renewable electricity. KEROGREEN meets UN ICAO CORSIA emission reduction targets and, as this fuel contains no sulphur, produces no soot and less NOx emissions, meets the EU Flightpath 2050 environmental objectives. At a generic level, coupling the renewable power sector to the fuel and chemical sector, Power-to-X, creates long-term, large-scale energy storage capacity needed to balance the grid and to strengthen EU energy security.
The KEROGREEN approach is based on plasma-driven dissociation of air-captured CO2, oxygen separation by high temperature oxygen exchange membranes and advanced Fischer-Tropsch (FT) synthesis to yield kerosene. Synergy between plasma-activated species and novel perovskite electrodes of the oxygen separator is expected to raise CO productivity, an important intermediate in the full synthesis scheme. High heat transfer FT technology and heat integration will raise energy efficiency. Hydrocracking tunes the kerosene yield to ASTM qualified aviation fuel. KEROGREEN technology is designed for modular upscaling, envisioned for decentralised, remote production plants, like off-shore wind parks or desert sited solar farms. It relies on the existing infrastructure for fuel storage and distribution and leaves current aircraft engine technology untouched.
KEROGREEN aims to deliver a container-sized plant able to produce up to 0.1 kg/hr kerosene at TRL 4. The project has identified an optimal path for integration of the individual units. The project challenge is to raise overall conversion of CO2 to liquid fuel, whilst reducing power consumption of the integrated KEROGREEN system.
At DIFFER the 1 kW 2.45GHz RF powered CO2 plasma reactor provides experimental data for the understanding of CO formation and loss processes. This serves as input for modelling the plasma chemistry and the turbulent transport. The newly developed 6 kW 915 MHz lab-reactor achieved first plasma whilst construction of the 6 kW container-sized plasma reactor module is in hand. Following the splitting of CO2 in CO and O2, the oxygen is separated out by electrochemical means based on oxygen selective, high temperature solid oxide cell (SOC) technology. After testing several different powder compositions produced by CERPOTECH, two novel perovskite materials were selected as candidate material for the SOC plasma electrode. This selection was supported by theoretical DFT computation of candidate materials as well as experiments on CO2 compatibility, CO backreaction and oxygen transport. Electrodes are deposited onto the electrolyte and characterized by VITO both microscopically and electrochemically. Electro-catalytic properties of the SOCs are assessed at DIFFER in plasma environment using a purpose built 13.5 MHz lab scale plasma reactor. Cell integration into a stack is contracted out to Industry, currently in progress with delivery expected early next reporting period. HyGear is working on the engineering of the oxygen separation module for integration and test by INERATEC in the container sized KEROGREEN system at KIT.
The CO purification module, based on Pressure Swing Adsorption (PSA), has been developed and assembled at HyGear and is currently being tested as a stand-alone CO purification system. Data gathered characterise and optimise performance under various operating conditions, including feed composition and flow rates. Data will be used to update the model of the integrated KEROGREEN system.
At KIT, the design of the Sorption-Enhanced Water-Gas Shift (SE-WGS) module employing advanced CO2 hydrotalcite-based adsorbent has been completed and construction of the module is ongoing. The experimental tests of the SE-WGS system in the laboratory are providing information required for the system operation. The innovative INERATEC evaporation cooled Fischer-Tropsch (FT) reactor based on micro-channel cooling design has shown desired process intensification. The high heat transfer FT module show 17% to 100% load flexibility necessary for intermittent power operation as compared with the limited 70-100% dynamic range of conventional plants. Mechanical size is an order of magnitude smaller, allowing integration in a container sized module close coupled to the renewable energy source. The KIT Hydro-Cracking (HC) unit for optimizing the kerosene product yield shows progress towards the desired aviation specification. First experimental results of the coupled three stage system show a broad alkene fraction narrowed down by hydrocracking and containing isomers for desired cold flow properties of jet-grade kerosene.
All experimental work has been accompanied by theoretical modelling, including simulation of the overall process chain detailing the chemical processes in the SE-WGS, FT and HC units at INERATEC and KIT. Similarly, KIT has built preliminary models to analyse the process life cycle including the material streams and environmental aspects and to assess the economy of synthetic kerosene produced by the KEROGREEN process in comparison with competing technologies.
Communication and Dissemination activities include the production of a KEROGREEN brochure, an up to date website, a leaflet and newsletters. A first international workshop on Plasma Catalysis for Renewable Fuels and Chemicals was organised at DIFFER on 15 November 2019, well attended by stakeholders and industry. KEROGREEN results were presented at international conferences and European networks such as EERA. Engagement with stakeholders including local airports and kerosene production and trading companies resulted in visibility of the KEROGREEN project and its EU funding basis.
KEROGREEN meets UN ICAO CORSIA and EU Flightpath 2050 requirements by producing Carbon Neutral Aviation Fuel. The concept benefits from already existing infra structure for fuel storage, transport and distribution while existing jet engine technology can be left as is. The production target of 0.1 kg/hr kerosene exceeds lab scale yield and allows identification of critical elements in the process chain progressing beyond State-of-the Art.
Chemical pathway analysis shows that thermal and material integration between the individual units is key to maximising energy and carbon efficiency. Recirculation of unreacted CO2 and product gases is expected to reach over 90% conversion of air captured CO2 to liquid fuels in a fully integrated KEROGREEN process.
During the next reporting period integration will take place of the KEROGREEN container sized system. Individual units will be integrated for proof-of-concept at system level and will allow identification of the main system bottlenecks and system optimisation. A market survey and business plan will identify the route to KEROGREEN upscaling, its potential applications and its impact on society. Current analysis indicates that the KEROGREEN approach has significant market impact provided KEROGREEN energy and conversion efficiency go up, accompanied by CO2 emission taxation to reach price equity with fossil based jet fuel.
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