January 13, 2023
Techno-economic Analysis of Sustainable Biofuels for Marine Transportation
AbstractRenewable, low-carbon biofuels offer the potential opportunity to decarbonize marine transportation. This paper presents a comparative techno-economic analysis (TEA) and process sustainability assessment of four conversion pathways: (1) hydrothermal liquefaction (HTL) of wet waste such as sewage sludge and manure; (2) fast pyrolysis (FP) of woody biomass; (3) landfill gas Fischer-Tropsch synthesis (LGFT); and (4) lignin-ethanol oil (LEO) from the lignocellulosic ethanol biorefinery utilizing reductive catalytic fractionation (RCF). These alternative marine biofuels have a modeled minimum fuel selling price between $1.68 and $3.98 per heavy fuel oil gallon equivalent (HFOGE) in 2016 US dollars based on a mature plant assessment. The selected pathways also exhibit good process sustainability performance in terms of water intensity compared to the petroleum refineries. Further, the O and S contents of the biofuels vary widely. While the non-HTL biofuels exhibit negligible S content, the raw biocrudes via HTL pathways from sludge and manure show relatively high S contents (> 0.5 wt%). Partial- or full- hydrotreatment can effectively lower the biocrude S content. Additionally, co-feeding with other low-sulfur wet waste such as food waste can provide another option to produce lower S-content raw biocrude to meet the target with further hydrotreating. This study indicates that biofuels could be a cost-effective fuel option for the marine sector. Marine biofuels derived from various feedstocks and conversion technologies could mitigate marine biofuel adoption risk in terms of feedstock availability and biorefinery economies.
Published: January 13, 2023