为可持续航空加油：可持续航空燃料和氢能航空燃料对技术、经济和环境的影响

每年，航空业产生的碳排放约占全球碳排放总量（大约10亿吨二氧化碳当量）的3%1。为减少温室气体排放，政策制定者、政府、行业组织和监管机构积极制定规则和奖惩措施，以期通过政策“组合拳”推动行业进一步脱碳，其中大多数都将2050年设为实现碳排放强度（C.I.）大幅度降低的目标时间点。航空业减少温室气体排放和降低运营总碳排放强度主要有三条途径：可持续航空燃料（SAF）、氢气和电气化。本文主要就SAF和氢气作商用航空的两种主要燃料来源进行分析。在过去几十年中，霍尼韦尔已经助力将可持续航空燃料变为现实。2009年，霍尼韦尔领导审批委员会2提交了将HEFA-SPK（加氢处理的酯和脂肪酸—合成链烷烃煤油）作为航空涡轮燃料列入美国试验和材料协会（ASTM）标准《ASTMD7566附件2》的申请，并于2011年7月获批。随后，霍尼韦尔与美国国防部合作，就美国海军和空军使用SAF给予了证明。2012年，AltAir Fuels燃料公司安装了首个采用霍尼韦尔UOP技术的商业可再生喷气燃料生产装置；2016年，美国联合航空公司成为第一家在定期航班上使用SAF的商业航空公司；2021年12月，首架100%使用霍尼韦尔UOP的Ecofining™工艺生产的SAF驱动的飞机由美国联合航空公司实现了历史性的首飞。霍尼韦尔UOP Ecofining™技术可以将11种生物基原料（如动物脂肪、废食用油、黄色油脂）转化为可再生柴油、可持续航空燃料和绿色石脑油。截至2022年，该技术已授权32次，目前已在6家工厂运行。霍尼韦尔认为，SAF是全球航空业脱碳的优秀选择。航空业脱碳霍尼韦尔观点可持续航空燃料（SAF）和氢燃料的对比分析1根据国际能源署航空排放数据2HEFA SPK 委员会 2011 年 7 月批准《ASTM D7566 附件 2》 每年航空业碳排放约占全球碳排放总量的3%大约10亿吨二氧化碳当量 目 录│4航空业脱碳霍尼韦尔观点可持续航空燃料（SAF）和氢燃料的对比分析摘要···········································································································································································································4可持续航空燃料1.原料可用性2.碳排放强度3.基础设施再利用4.对比氢气的结构价格优势5.航空旅行需求的非弹性特征氢燃料·································································································································································································111.氢气的能力优势2.体积能量密度障碍3.支持基础设施4.氢气、传统Jet A与SAF的碳排放强度对比市场发展路标霍尼韦尔— 推动航空运输的未来对可持续发展的承诺 ···········································································································································································5·······················································································································································································5·························································································································································································6···············································································································································································8···························································································································································8···················································································································································10············································································································································································11·······································································································································································11·················································································································································································11··············································································································································································13·······································································································································································15 ····················································································································2··············································································································12··························································································································14 摘 要尽管氢气具备一些有吸引力的物理特性（例如：高比能、当配送网络成熟时具备极低生命周期排放潜力），但要实现商业化规模，还需要应对几个挑战：一是飞机燃料需要液态氢以满足操作和安全要求；二是液态氢的低体积能量与常规喷气燃料相比，需要约四倍的体积4管道和储存）需要扩充；四是氢液化需要新的投资。此外，其他难以减排的行业（如钢铁和水泥制造业）对氢燃料的争夺也可能会导致低C.I.氢（即低碳氢/蓝氢和可再生氢/绿氢）的市场价格上涨。可再生氢的可用性可能会受到电解槽调试速度和电网脱碳速度的限制，后者也会受到其他行业电动化步伐的影响，导致电力总需求增加。低碳排放强度下原料的可用性1目前，通过加工脂肪、油和油脂（统称为“FOG”）生产的SAF已被视为一种成熟的生产路线，但预计原料供应量仅够满足2030年之前的需求3年以后，乙醇制航空燃料（ETJ）和生物质制液体燃料（BTL）等其他SAF路线将成为下一批能够满足SAF需求的可行原料，其原因主要在于三方面： ；三是现有飞机和配套基础设施（如压缩、基础设施再利用的潜力与氢气相比的结构价格优势23。2030 虽然FOG工艺从技术角度看已经成熟，但内部分析表明，其原料供应量仅能满足2030年之前的需求。为了让SAF作为航空脱碳载体被广泛应用，增加低C.I.的产量至关重要。在使用当前原料和当前农业工艺的情况下，要满足未来的SAF需求，需要将用地数量增加至原来的两倍。然而，随着农业实践的不断发展和利用糖或生物质作为原料的下一代生产路线的不断改进（例如ETJ和BTL），未来对产量和降低C.I.方面的需求都可以得到解决。因此，满足SAF增量需求所需的额外用地预计将远少于第一代原料生产所需的用地。糖和生物质原料都比FOG更丰富。根据美国能源部生物能源技术部门的一项研究，美国每年能够以可持续的方式收集大约10亿千吨的生物质，这些生物质可以转化为超过500亿加仑（约1900亿升）的低C.I.燃料580%~94%碳排放）。此类生物质资源包括木材加工废料、农业和林业残留物、专用能源作物、油籽和城市固体废物流等。这些原料加在一起可以满足美国航空业和其他运输方式对普适性低碳燃料的燃料需求，同时还可用于生产高价值的生物产品和可再生化学品6。用于SAF生产的生物质作物可以在农闲季节种植，帮助农民赚取额外收入、减少土壤养分损失、改善土壤和水质，并有助于控制土壤侵蚀。可持续航空燃料5美国能源部生物能源技术办公室 SAF 生物质报告6美国能源部能源效率和可再生能源办公室，可持续航空燃料、生物能源技术办公室1原料可用性 10亿千吨生物质超过500亿加仑的低C.I.燃料美国每年能够以可持续的方式收集大约转化为可减少碳排放80%~94% （可减少 SAF的碳排放强度高度依赖于以下变量：生产路线（也称“转化”，包括传统石油精炼、HEFA、ATJ酒精制喷气燃料、ETJ乙醇制航空燃料）、原料类型（如玉米、甘蔗、棕榈、大豆）、农业实践和运输基础设施（如卡车、货船）。例如，在传统炼油厂中，使用原油制成Jet A航空燃油的C.I.约为85~95克CO2e/MJ10。相对而言，ETJ路线（注意：预计到2050年，ETJ将占总供应组合的约50%）生产的SAF的生命周期C.I.在约24~78克CO2e/MJ11的范围内。这