Assessment of Bio-jet Fuel Production through Alcohol-to-Jet Pathways from Lignocellulosic Biomass
Creators: Nayan, Nusrat F
Publisher: name: University of Alberta Library
Year: 2024

<p>The aviation industry worldwide consumes approximately 1.531.7 billion barrels/year ofconventional jet and 140 million litres/year of bio-jet fuel and it has been estimated thatcommercial aviation has contributed approximately 2-6% to global carbon emissions. Biomassderivedjet (bio-jet) fuel may be a promising solution for the aviation industry because of the fuel’spotential to reduce CO2 emissions over its life cycle. Bio-jet from edible, non-edible food cropsand lignocellulosic biomasses compete with the cultivable lands, but algae-based biomass doesnot. When bio-jet fuel sourced from algae is used for aviation, GHG emissions can be reducedsignificantly relative to the conventional jet fuel. However, extensive research, development, anddemonstration are being conducted to produce renewable jet fuels from a variety of feedstocks andpathways.This thesis is focused on opportunities to produce alternative jet fuel components fromdifferent alcohols (the alcohol-to-jet [AJT] pathway). It also provides a brief overview of otherconversion technologies (the oil-to-jet [OTJ], sugar-to-jet [STJ], and gas-to-jet [GTJ] pathways).The ATJ pathway consists of processes that convert platform alcohol molecules to an alternativejet fuel blend stock through catalytic reactions historically used by the petrochemical industry. Forthis study, a literature review was conducted for different alcohols and associated productionprocesses. Further, selected variations of all the process pathways were evaluated.For this study, process models were developed for ethanol-to-jet production processes.Techno-economic assessment was conducted. In addition, five scenarios, each with two cases wereassessed. In Case 1 for all five scenarios, feedstock ethanol and hydrogen were sourced from aniii upstream process of a 2000 dry tonnes/day--1 production plant (using spruce wood chips). In Case2, merchant ethanol was used. Two additional single-case scenarios were developed using nbutanoland isobutanol as feedstocks. In the best-case scenario, bio-jet production costs were$1.43/kg ($0.94/L) with a final yield of 47%. To understand the differences in bio-jet fuelproduction costs at different capacities, a wide range of production capacities (from 48 to 12,000tonnes day−1) was considered, and associated scale factors were developed for the individual unitsand the overall plants. The optimal size at which the cost of production is lowest is 12,000 drytonnes/day−1 (50,000 kg/hr). With increasing capacity, feedstock cost significantly increases, whilethe capital cost per unit output decreases. The scale factor was determined through the developedprocess and techno-economic models for the overall plants, major units, and equipment.A sensitivity analysis was conducted to estimate the impact of various process parameterson the final cost of bio-jet fuel. The results indicate that production cost is most sensitive tofeedstock cost, followed by the plant lifetime, discount rate, and capital cost. A Monte Carlosimulation was used to assess a change the production cost of bio-jet fuel and generate mean andmost likely prices for Cases 1 and 2 in both the base and best-case scenarios at a 95% confidencelevel.The aviation industry is mainly interested in high-quality bio-jet fuel as it is nearly carbonneutral and could help provide energy independence. In short, low-carbon fuels are seen as bothattractive and beneficial.</p>