Conversion of waste to sustainable aviation fuel via Fischer–Tropsch synthesis: Front‐end design decisions

Abstract

Front-end design decisions for a process to produce sustainable aviation turbine fuel from waste materials were presented. The design employs distributed conversion of wastes to oils, which are then transported to a central facility for gasification, syngas cleaning, Fischer-Tropsch synthesis and refining, that is, a spoke-and-hub approach. Different aspects of the front-end design, that is, the steps up to syngas cleaning, were evaluated. The evaluation employed a combination of case studies, calculations, experimental investigations, and literature review. The supply of sustainable aviation fuel (SAF) as a 50:50 mixture of wastederived and petroleum-derived kerosene to meet the demand of an international airport (Pearson, Toronto) was employed as case study. The amount of raw material required made it impractical to make use of only one type of waste. Using the same set of assumptions, it was shown that in terms of cumulative transport distance required, a spoke-and-hub approach was twice as efficient as centralized processing only. Technologies for decentralized production of oils were assessed, and oils produced by pyrolysis and hydrothermal liquefaction (HTL) in pilot-scale and larger facilities were procured and characterized. These oils were within the broader compositional space of pyrolysis oils and HTL oils reported in laboratory studies. The oil compositions were employed to study the impact of oil composition on entrained flow gasification. Thermodynamic equilibrium calculations of pyrolysis and HTL oil entrained flow gasification resulted in H 2 / CO ratios of syngas and O 2 consumption rates in a narrow range, despite the diversity of feeds. At the same time, to produce an equal molar amount of syngas (H 2 + CO), less HTL oil than pyrolysis oil was required as feed. Gas cleaning technologies were reviewed to ascertain types of contaminants anticipated after gasification, their removal effectiveness, and Fischer-Tropsch catalyst poisoning 1763

Viscosity–Temperature Relationship and Binary Viscosity Mixing Rules for Fast Pyrolysis and Hydrothermal Liquefaction Oil Blends

“…FP and HTL oils evaluated in this study were obtained from continuous systems, operating at pilot and demonstration scales. Table presents the characterization of the oils, which was reported before in ref . Heating values were calculated based on their elemental composition …”

“…In the context of biofuel production, if biomass and waste raw materials are to be converted to oils and used at a large scale, then it is unlikely that the oils could be derived from a single source. This type of scenario was investigated, 11 and for a practical front-end design in a fuel production process, blending of oils from different sources is necessary. This situation is analogous to what is found in petroleum refining, where crude oils from different sources are blended for refining.…”

“…In the context of biofuel production, blending of intermediate oils obtained from different feedstocks, as well as from the different thermochemical processes, may be advantageous. Such blending may even be necessary in cases where the capacity at which the oil is required makes it impractical, and likely, economically not feasible to use only one source of biomass or waste. , Furthermore, analogous to a petroleum refinery, blending of intermediate oils may also be desirable to adjust the composition and properties of the oil feed (such as the oil viscosity) in order to facilitate handling, transport, and conversion in further upgrading operations …”

“…Such blending may even be necessary in cases where the capacity at which the oil is required makes it impractical, and likely, economically not feasible to use only one source of biomass or waste. 11,12 Furthermore, analogous to a petroleum refinery, blending of intermediate oils may also be desirable to adjust the composition and properties of the oil feed (such as the oil viscosity) in order to facilitate handling, transport, and conversion in further upgrading operations. 11 Despite its relevance, studies on blending of FP and/or HTL oils are limited.…”

“…11,12 Furthermore, analogous to a petroleum refinery, blending of intermediate oils may also be desirable to adjust the composition and properties of the oil feed (such as the oil viscosity) in order to facilitate handling, transport, and conversion in further upgrading operations. 11 Despite its relevance, studies on blending of FP and/or HTL oils are limited. Blending of raw pyrolysis oils, namely, nonupgraded FP oils, with solvents and additives has been reported.…”