Hydrothermal liquefaction of pig carcasses to biofuel: A techno-economic analysis

Hydrothermal liquefaction (HTL) of pig carcasses is a promising treatment method. However, the commercial viability of a large-scale pig carcasses HTL plant needs further evaluation. In this study, a system for converting pig carcasses to biofuel via HTL was constructed using Aspen Plus. Four property methods for calculating the specific enthalpy and specific heat capacity of water were compared. Sensitivity and uncertainty analyses were conducted to investigate the key parameters determining the process economy. Finally, the economic potential of different feedstocks and processes was discussed. The results showed the baseline minimum fuel selling price (MFSP) was $0.432 per liter gasoline equivalent (LGE-1). The MFSP decreased as the plant scale increased, falling below that of petroleum-based fuels when the feed flow rate exceeded 1600 kg h-1. Feed solid loading and bio-oil yield were key operational parameters affecting MFSP, while annual uptime, plant life, and internal rate of return were identified as crucial capital parameters. The uncertainty analysis showed the range of 10-90% of MFSP was $0.356 to $0.549 LGE-1, with an average value of $0.454 LGE-1. HTL of pig carcass has demonstrated promising prospects for large-scale application.