Pilot-scale hydrotreating of catalytic fast pyrolysis biocrudes: process performance and product analysis

Verdier, Sylvain; Mante, Ofei D.; Hansen, Asger B.; Poulsen, Kristoffer G.; Christensen, Jan H.; Ammtizboll, Nadia; Gabrielsen, Jostein; Dayton, David C.

doi:10.1039/d1se00540e

Cited by 9 publications

(13 citation statements)

References 48 publications

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“…Although successful hydrotreatment of bio-oils in fixed bed reactors has been reported previously, several issues were noted during these studies, such as catalyst deactivation, − plugging, or coke formation in the reactors . Potentially, plugging may even occur in the heated transfer lines to the reactors.…”

Section: Resultsmentioning

confidence: 94%

Derivatizing of Fast Pyrolysis Bio-Oil and Coprocessing in Fixed Bed Hydrotreater

et al. 2022

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In several countries forest-based biofuels are being developed and to some extent also deployed. Fast pyrolysis bio-oil produced from, for example, sawdust, has now been coprocessed in fluid catalytic cracking refinery units in a number of commercial trials. However, this application is limited to about 10% of the total feed, and coprocessing in conventional fixed bed hydrotreaters is necessary to reach the high potential with this feedstock. Feeding and upgrading of fast pyrolysis bio-oil in a fixed bed reactor configuration is still problematic due to the inherent bio-oil properties. Stabilization of reactive compounds in fast pyrolysis bio-oil and mild hydrotreatment in a separate refining unit prior to refinery integration has therefore been developed the past decade. Another approach, presented here, involves complete dewatering of fast pyrolysis bio-oil by azeotropic distillation using mesityl oxide as the solvent, followed by conversion of the abundant hydroxyl compounds via mixed anhydride esterification methodology using an external source of mixed carboxylic acids of different chain lengths originating from renewable tall oil fatty acids, providing a lipophilic feed component. Dewatering and derivatizing were carried out in reactors up to 50 dm3 with a mass ratio of fast pyrolysis bio-oil to tall oil fatty acid of 10:13. The produced lipophilic oils were miscible with a petroleum light gas oil fraction and exhibited superior stability even after accelerated aging at elevated temperature (80 °C). The derivatized oils were thus mixed with light gas oil, with a proportion of 30 wt % derivatized oil in final blends and hydrotreated continuously in pilot fixed bed reactors for 14 days at 4 operating conditions without plugging or excessive exotherms. The test conditions were varied; the reactor pressure was either 55 or 80 bar, temperature 380 or 400 °C, and liquid hourly space velocity either 1 or 2 h–1 during the hydrotreatment. Successful hydrodeoxygenation and desulfurization were accomplished, whereas an increasing nitrogen concentration could be observed in the liquid products with the particular catalyst and reaction conditions employed. The observed hydrogen consumption (15–20 g/kg feed) was compared with the stoichiometric consumption for direct deoxygenation and with typical consumptions for industrial hydrotreated vegetable oil processing. The measured biogenic carbon content in hydrotreated liquid products (26.7%) agreed extremely well with the calculated biogenic carbon content in the hydrotreating feed (26.6%) that consisted of the blend of derivatized oil and petroleum light gas oil. The overall results are very promising since simple unit operations can be used to produce derivatized fast pyrolysis bio-oils that do not need additional standalone hydrotreating units but can be coprocessed in existing ones.

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Section: Resultsmentioning

confidence: 94%

Derivatizing of Fast Pyrolysis Bio-Oil and Coprocessing in Fixed Bed Hydrotreater

et al. 2022

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Section: Direct Liquefaction Of Waste Materialsmentioning

confidence: 99%

“…Upgrading pyrolysis and HTL oils to transportation fuels via hydrotreating is one route under development that could open a large market, but catalyst deactivation during upgrading remains a major challenge. 103,108,109 Additionally, it requires a considerable amount of H 2 . Another suggested pathway is co-processing such oils in fluid catalytic cracking (FCC) units, but it is hindered by concerns about incompatibility of these oxygenate-rich Samples provided under an agreement that prohibits disclosing the supplier.…”

Section: State Of Biomass and Waste Liquefaction Technologymentioning

confidence: 99%

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

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Chauhan

et al. 2022

Energy Science & Engineering

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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

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“…In contrast, a recent study reported that several biocrudes produced from catalytic biomass pyrolysis were upgraded with varying degrees of success. 42 Three of the CFP biocrude feeds had similar oxygen content (25−29 wt %). The feed with the highest oxygen content also had the highest concentrations of levoglucosan and carboxylic acids.…”

Section: ■ Summary and Conclusionmentioning

confidence: 99%

“…RCFP biocrude was hydrotreated in a pilot-scale hydroprocessing unit to produce advanced hydrocarbon biofuels and blendstocks. A summary is provided of the design and operation of this unit that has been described in more detail in the recent literature. − The hydroprocessing unit consists of five main sections: (1) an oil feed system equipped with pumps and flow control, (2) a gas feed system, (3) a reactor system, (4) a gas–liquid separator system, and (5) a gas and liquid sampling system.…”

Section: Pilot-scale Hydrotreating Reactor Systemsmentioning

confidence: 99%

Integrated Reactive Catalytic Fast Pyrolysis: Biocrude Production, Upgrading, and Coprocessing

et al. 2022

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This study investigates hydrotreating biocrude produced by reactive catalytic fast pyrolysis (RCFP), a direct biomass liquefaction process that combines a robust hydrodeoxygenation catalyst for in situ pyrolysis with excess hydrogen at ambient (low) pressure. The RCFP process leverages advantages from catalytic fast pyrolysis (process simplicity and improved biocrude quality) and biomass hydropyrolysis (enhanced hydrodeoxygenation) to produce a thermally stable biocrude that can be upgraded in a single hydroprocessing step or coprocessed with petroleum refining intermediates to produce gasoline- and diesel-range hydrocarbons. RCFP biocrude (9.4 kg, 19.3 wt % oxygen, dry basis) was hydrotreated continuously for 144 h, in a pilot-scale hydroprocessing unit, at 138 barg (2000 psig) hydrogen pressure, 0.31 h–1 space velocity, and an average temperature of 300 °C. Blends of 10%, 15%, and 20% RCFP biocrude in light gas oil were also upgraded over a NiMo hydrotreating catalyst at 350 °C in hydrogen at 50–70 barg (725–1015 psig). The stand-alone hydrotreating results indicate that, even though there was no pressure drop increase indicative of reactor fouling, hydrotreating catalyst deactivation was evident as the product density increased from 0.852 to 0.955 kg/L after 144 h time-on-stream. Additionally, the oxygen content of the upgraded liquid product increased from 1.4 wt % to 5.5 wt % over the course of the experiment. In the coprocessing test, little or no catalyst deactivation was observed with the 10% RCFP blend on the basis of the density of the hydrotreated products. However, the hydrotreating catalyst activity was lower during upgrading of the 20% and 15% blends. On the basis of hydrodesulfurization of light gas oil, the relative activity of the hydrotreating catalyst decreased by 40% during the 1000 h coprocessing test. Fortunately, this level of deactivation measured at this small scale does not correlate to a prohibitively large deactivation rate at the industrial scale.

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Pilot-scale hydrotreating of catalytic fast pyrolysis biocrudes: process performance and product analysis

Abstract: Catalytic fast pyrolysis (CFP) is a technology option for producing advanced biofuels from hydrocarbon-rich biocrude intermediates. The relatively high oxygen content of biocrudes compared to petroleum intermediates increases hydrogen consumption...

Cited by 9 publications

References 48 publications

Derivatizing of Fast Pyrolysis Bio-Oil and Coprocessing in Fixed Bed Hydrotreater

Derivatizing of Fast Pyrolysis Bio-Oil and Coprocessing in Fixed Bed Hydrotreater

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

Integrated Reactive Catalytic Fast Pyrolysis: Biocrude Production, Upgrading, and Coprocessing

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