Improving resource efficiency and reducing carbon emissions through low-temperature, low-pressure ammonia synthesis

氨是全球第二大最常生产的工业化学品，估计全球产量达到1.76亿吨/年（2022年）。大约80%的氨用于化肥生产，在增加农业产量和支持不断增长的全球人口方面发挥着关键作用。事实上，据估计，化肥中的氨现在供养着全球大约一半的人口。氨合成目前依赖于有110年历史的哈伯-博世工艺，该工艺在高温下（？400摄氏度），高压（？（i）材料：在高温、高压条件下操作反应器需要大量的材料投资和高资本支出成本。值得注意的是，一个85万吨/年的大型氨厂估计需要225吨不锈钢用于合成反应器，资本支出估计为80亿英镑。(ii)矿物质：Haber-Bosch工艺依赖于熔融铁催化剂，其通常通过将来自瑞典的天然磁铁矿与各种促进剂熔融、冷却熔体并将熔体机械造粒成小颗粒，然后将其筛选以获得目标粒度来制备。一个85万吨/年的大型氨厂估计需要74，520公斤的熔铁催化剂，使用寿命约为10年。由于即使是预还原、稳定的熔铁催化剂也需要30-40小时的活化时间，因此哈伯-博世工艺在“始终在线”的条件下运行，限制了生产灵活性，并排除了使用间歇性可再生能源作为电源。哈伯-博世工艺面临的资源效率挑战是高能源需求和碳排放。哈伯-博世工艺消耗约2%的全球能源预算（8.6 EJ/年），并贡献约1.8%的全球二氧化碳排放量（5亿吨/年）。预计到2050年，氨的需求将增长近40%，这主要是由化肥需求推动的，常规氨生产与全球净零目标不相容。通过材料和制造资源效率的创新英国资金呼吁汇集了一个世界级的工业和学术财团，通过开发低温，低压氨合成工艺

Ammonia is the second most commonly produced industrial chemical worldwide, reaching an estimated global production of 176 megatonnes/year (2022). Approximately 80% of ammonia is used for fertiliser production, playing a critical role in increasing agricultural output and supporting the growing global population. Indeed, it is estimated that ammonia in fertiliser now supports approximately half of the global population.Ammonia synthesis currently relies on the 110-year old Haber-Bosch process, which reacts nitrogen and hydrogen over fused-iron catalysts under high-temperature (?400 degC), high-pressure (?200 bar) conditions.This process faces two key resource efficiency issues:(i) Materials: Operating reactors under high-temperature, high-pressure conditions requires significant materials investment and high CAPEX costs. Notably, a large-scale 850,000 tonne/year ammonia plant requires an estimated 225 tonnes of stainless steel for the synthesis reactors and costs an estimated £0.8BN in CAPEX.(ii) Minerals: The Haber-Bosch process relies on a fused-iron catalyst, which is typically prepared by melting natural magnetite from Sweden with various promoters, cooling the melt, and mechanically granulating the melt into small particles, which are then screened to obtain the target particle size. A large-scale 850,000 tonne/year ammonia plant requires an estimated 74,520 kg of fused-iron catalyst, with a lifetime of approximately 10 years. Since even pre-reduced, stabilised fused-iron catalysts require 30-40 hours for activation, the Haber-Bosch process is operated under "always-on" conditions, limiting production flexibility and precluding the use of intermittent renewable energy as a power source.Underpinning the resource efficiency challenges associated with the Haber-Bosch process are the high energy requirements and carbon emissions. The Haber-Bosch process consumes approximately 2% of the global energy budget (8.6 EJ/year) and contributes around 1.8% of global carbon dioxide emissions (500 megatonnes/year). With demand for ammonia projected to rise nearly 40% by 2050, largely driven by fertiliser requirements, business-as-usual ammonia production is incompatible with global net-zero targets.Innovate UK funding through Resource Efficiency for Materials and Manufacturing call brings together a world-class consortium spanning industry and academia to improve resource efficiency and reduce carbon emissions through developing a low-temperature, low-pressure ammonia synthesis process.