Converting waste paper sludge to sustainable aviation fuel (SAF) offers a circular economy strategy to decarbonize the aviation sector. This study develops a life-cycle assessment (LCA) for converting high-ash paper sludge to SAF in the U.S. using a catalytic sugar upgrading system that consists of ash removal, enzymatic hydrolysis, dehydration, aldol condensation, and hydroprocessing. The LCA is coupled with a process simulation for an industrial-scale biorefinery based on experimental data. We quantified the carbon intensity as 35.7–41.8 gCO₂eq MJ^–1 SAF (−636 to −584 gCO₂eq per dry kg paper sludge) with acetone as a solvent, renewable fuel, and biobased chemicals; this is further reduced to 5.1–11.1 gCO₂eq MJ^–1 (−925 to −873 gCO₂eq per dry kg paper sludge) if ash is recycled and used for substituting cement. Converting 1 dry kg paper sludge to SAF with acetone, renewable fuel, and biobased chemicals (−925 to −584 gCO₂eq) is more climate beneficial than landfilling without landfill gas recovery (791 gCO₂eq) and with landfill gas recovery (−294 gCO₂eq). More than 330 million gallons of SAF can be produced annually (>4 million dry t paper sludge/year in the U.S.), resulting in a reduction of 2–7 million tCO₂eq.

中文翻译：

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从造纸污泥中提取的可持续航空燃料的生命周期评估

将废纸污泥转化为可持续航空燃料（SAF）提供了航空业脱碳的循环经济战略。本研究开发了生命周期评估 (LCA)，在美国使用催化糖升级系统将高灰分造纸污泥转化为 SAF，该系统包括除灰、酶水解、脱水、醇醛缩合和加氢处理。 LCA 与基于实验数据的工业规模生物精炼厂的过程模拟相结合。我们将丙酮作为溶剂、可再生燃料和生物基化学品的碳强度量化为 35.7–41.8 gCO ₂ eq MJ ^–1 SAF（每公斤干燥造纸污泥−636 至−584 gCO ₂ eq）；如果灰分被回收并用于替代水泥，则该值可进一步减少至 5.1–11.1 gCO ₂ eq MJ ^–1（每千克干燥造纸污泥−925 至−873 gCO ₂ eq）。使用丙酮、可再生燃料和生物基化学品（−925 至 −584 gCO 2 当量）将 1 公斤干造纸污泥转化为 SAF比不进行垃圾填埋气回收（791 gCO ₂当量）和进行垃圾填埋气回收（ −584 gCO ₂当量）的填埋对气候更有利。294 gCO ₂当量）。每年可生产超过 3.3 亿加仑的 SAF（美国每年超过 400 万干吨造纸污泥），从而减少 2-700 万吨CO ₂当量。