Abstract：
The present paper compared, through life cycle assessment (LCA), the production of aviation biofuel from two hydrothermal routes of microalgae cultivated in wastewater. Hydrothermal liquefaction (HTL) and gasification followed by Fischer-Tropsch synthesis (G + FT) were compared. Both routes included biomass production, hydrotreatment for biofuel upgrading, and product fractionation. Secondary data obtained from the literature were used for the cradle-to-gate LCA. G + FT had a higher impact than HTL in the 18 impact categories assessed, with human carcinogenic toxicity exerting the most harmful pressure on the environment. The catalysts were the inputs that caused the most adverse emissions. The solvent used for bio-oil separation also stood out in terms of impacts. In HTL, emissions for global warming were -51.6 g CO2 eq/MJ, while in G + FT, they were 250 g CO2 eq/MJ. At the Endpoint level, HTL resulted in benefits to human health and ecosystems, while G + FT caused environmental damage in these two categories, as well as in the resources category. In the improvement scenarios, besides considering solid, aqueous, and gaseous products as co-products rather than just as waste/emissions, a 20% reduction in catalyst consumption and 90% recovery were applied. Thus, in HTL, 39.47 kg CO2 eq was avoided, compared to 35.44 kg CO2 eq in the base scenario. In G + FT, emissions decreased from 147.55 kg CO2 eq to the capture of 8.60 kg CO2 eq.
摘要：
本文比较了,通过生命周期评估(LCA)，从废水中培养的微藻的两条水热路线生产航空生物燃料。比较了水热液化（HTL）和气化后的费托合成（GFT）。两条路线都包括生物质生产，生物燃料升级的加氢处理，和产品分馏。从文献中获得的次要数据用于摇篮到门的LCA。在评估的18个影响类别中，G+FT的影响高于HTL，与人类致癌毒性对环境施加最有害的压力。催化剂是造成最不利排放的输入。用于生物油分离的溶剂在影响方面也很突出。在HTL中,全球变暖的排放量为-51.6g二氧化碳当量/MJ，在G+FT中，它们是250克CO2当量/MJ。在端点级别，HTL为人类健康和生态系统带来了好处，虽然G+FT在这两个类别中造成了环境破坏，以及资源类别。在改进方案中，除了考虑固体，水性，和气态产物作为副产物，而不仅仅是废物/排放物，应用了20%的催化剂消耗减少和90%的回收率。因此，在HTL中,避免了39.47千克二氧化碳当量，与基本情景中35.44千克二氧化碳当量相比。在G+FT中，排放量从147.55千克二氧化碳当量减少到8.60千克二氧化碳当量的捕获。
