MIX-MOXes - Mixed Metal Oxides Energy Stations for zero-carbon thermal energy generation with integrated heat storage

供热是现代社会的重要基础；然而，它的脱碳问题在很大程度上仍未得到解决。三个关键的根本性挑战仍有待解决：1)传统化石燃料需要被具有大量能量和功率密度的零碳能源载体取代，以实现高效供热；2)需要部署高效且具有成本效益的热能储存能力；3)需要在循环经济背景下开发零碳发电和储热技术。尽管付出了巨大的努力，但迄今为止提出的解决方案都没有完全取代化石燃料在产生和储存热量方面提供的基本功能。最近的研究从理论上预测，在相当的温度和反应速率下，铁和铝等丰富金属的微尺度粉末的快速氧化（即燃烧）可以释放出传统燃料的理论能量存储密度（~8400 MJ/m3）的10倍，但不会排放二氧化碳。这是一种非凡但在很大程度上未经证实的潜力；目前提出的零碳产热蓄热技术仅达到传统化石燃料蓄热密度和转化反应速率的~15-20%。此外，金属氧化物颗粒是快速氧化反应的唯一预期产物。一旦收集起来，人们相信氧化物颗粒可以通过可再生能源驱动的过程再生回金属粉末，从而关闭能源和资源循环，从而在循环经济中提供电力-金属- x路径。然而，需要新的激进技术和工艺，以可控和有效的方式燃烧和再生金属粉末。由于缺乏对控制金属粉末反应流动机制的基本理解和应用，这是否可能仍然不清楚。因此，这是一个具有巨大应用潜力的高风险发现研究领域。该项目设定了一个雄心勃勃的目标，即通过概念验证研究，建立一个全新的热能产生和蓄热综合系统家族的技术潜力，该系统利用了零排放燃烧和可回收金属粉末再生的基本现象。其核心是实验与数值/理论相结合的方法。该项目将揭示粒子级相互作用对点火和再生过程的影响；在组件水平上，概念验证实验将在实验室规模上演示金属粉末气溶胶的连续燃烧，同时捕获氧化物产物以进行后续再生。最后，在整个过程层面，将制定路线图，以确定技术升级的未来研究需求并管理相关的升级风险。如果被证明是成功的，Mix-MOXes项目将为未来英国循环经济背景下颠覆性的零碳发电和储热技术奠定基础。因此，它有可能取代或改造英国基于化石燃料的资产，特别是在大规模热储联产的地方：i)集中能源生产和储存在区域供热系统中，ii)工业过程热用于难以脱碳的英国能源密集型行业，iii)改造或更换发电站，利用现有基础设施在电网规模上提供联合零碳发电和储存。我们初步的保守估计显示，mix - mox可以为英国每年节省超过4000万吨的二氧化碳，同时为材料资源提供新的循环路线。

The provision of heat is a vital foundation of modern society; however, its decarbonization remains largely unaddressed. Three key fundamental challenges remain to be addressed: 1) traditional fossil-fuels need to be replaced with zero-carbon energy carriers with substantial energy and power density for efficient generation of heat; 2) efficient and cost-effective thermal energy storage capacity needs to be deployed and 3) zero-carbon technologies for generation and storage of heat need to be developed in a circular economy context. Despite significant efforts, none of the solutions so far proposed fully replace the essential functions that fossil fuels provide in generation and storage of heat. Recent studies theoretically predicted that fast oxidation - i.e. combustion - of micro-scale powders of abundantly available metals such as iron and aluminium could release a theoretical energy storage density 10x of traditional fuels (~8400 MJ/m3), at comparable temperature and reaction rates, but without CO2 emissions. This is a remarkable but largely unproven potential; so far proposed zero-carbon heat generation and heat storage technologies only reach ~15-20% storage density and conversion reaction rate of traditional fossil fuels. Furthermore, metal oxide particles are the only expected product of the fast oxidation reaction. Once collected it is believed that oxide particles could be regenerated back to metal powder via renewable-energy driven processes, closing the energy and resources cycles and thus providing Power-to-Metal-to-X paths within a circular economy. However, new radical technologies and processes are needed to combust and regenerate metal powders in a controllable and efficient manner. Whether this is possible remains unclear due to the absence of fundamental understanding and application of the mechanisms controlling reactive flows of metal powders. Here therefore lies a field of high-risk discovery research with huge application potential. This project sets the ambitious goal to establish the technological potential - through a proof-of-concept study - of an entirely new family of integrated systems for thermal energy generation and heat storage that harness the fundamental phenomenon of zero-emission combustion and regeneration of all-recyclable metal powders. At its centre is a combined experimental & numerical/theoretical approach. The project will unveil the influence of particle-level interactions on ignition and regeneration processes; at component level proof-of-concept experiments will demonstrate at lab-scale continuous combustion of metal powder aerosol with concurrent capture of oxide products for subsequent regeneration. Finally, at the whole process level, a roadmap will be developed to set future research needs for upscaling of the technology and manage associated upscaling risks.If proven successful, Mix-MOXes project could therefore provide the foundations for a disruptive zero-carbon technology for heat generation and storage in the future UK circular economy context. As such, it has the potential to replace or retrofit UK fossil-fuel based assets, particularly where combined heat and storage is delivered at large scale: i) centralized energy generation and storage in district heating systems, ii) industrial process heat for hard to decarbonize UK energy-intensive industries, iii) Retrofit or replacement of power stations to exploit existing infrastructure to provide combined zero-carbon generation and storage at grid scale. Our preliminary conservative estimation reveals that Mix-MOXes could provide the UK with CO2 savings in excess of 40MtCO2/year alongside new circular routes for material resources.