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Bergvall, N., Cheah, Y. W., Bernlind, C., Bernlind, A., Olsson, L., Creaser, D., . . . Öhrman, O. G. (2024). Upgrading of fast pyrolysis bio-oils to renewable hydrocarbons using slurry- and fixed bed hydroprocessing. Fuel processing technology, 253, Article ID 108009.
Open this publication in new window or tab >>Upgrading of fast pyrolysis bio-oils to renewable hydrocarbons using slurry- and fixed bed hydroprocessing
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2024 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 253, article id 108009Article in journal (Refereed) Published
Abstract [en]

Liquefaction of lignocellulosic biomass through fast pyrolysis, to yield fast pyrolysis bio-oil (FPBO), is a technique that has been extensively researched in the quest for finding alternatives to fossil feedstocks to produce fuels, chemicals, etc. Properties such as high oxygen content, acidity, and poor storage stability greatly limit the direct use of this bio-oil. Furthermore, high coking tendencies make upgrading of the FPBO by hydrodeoxygenation in fixed-bed bed hydrotreaters challenging due to plugging and catalyst deactivation. This study investigates a novel two-step hydroprocessing concept; a continuous slurry-based process using a dispersed NiMo-catalyst, followed by a fixed bed process using a supported NiMo-catalyst. The oil product from the slurry-process, having a reduced oxygen content (15 wt%) compared to the FPBO and a comparatively low coking tendency (TGA residue of 1.4 wt%), was successfully processed in the downstream fixed bed process for 58 h without any noticeable decrease in catalyst activity, or increase in pressure drop. The overall process resulted in a 29 wt% yield of deoxygenated oil product (0.5 wt% oxygen) from FPBO with an overall carbon recovery of 68%.

Place, publisher, year, edition, pages
Elsevier B.V., 2024
Keywords
Biofuel, Deoxygenation, Hydroprocessing, Pyrolysis, Renewable, Slurry, Biofuels, Catalyst deactivation, Fuel storage, Oxygen, Deoxygenations, Fast pyrolysis bio-oil, Fixed bed, Fixed-bed process, Lignocellulosic biomass, Ni-Mo catalyst, Oil product, Oxygen content, Catalyst activity
National Category
Chemical Engineering
Identifiers
urn:nbn:se:ri:diva-71914 (URN)10.1016/j.fuproc.2023.108009 (DOI)2-s2.0-85179611112 (Scopus ID)
Funder
Swedish Energy Agency, 41253-2
Note

 Correspondence Address: N. Bergvall; Research Institutes of Sweden AB, Borås, Box 857, SE-501 15, Sweden; This work was funded by the Swedish Energy Agency, project number 41253-2

Available from: 2024-02-22 Created: 2024-02-22 Last updated: 2024-05-17Bibliographically approved
Janosik, T., Nilsson, A. N., Hällgren, A.-C., Hedberg, M., Bernlind, C., Rådberg, H., . . . Öhrman, O. (2022). Derivatizing of Fast Pyrolysis Bio-Oil and Coprocessing in Fixed Bed Hydrotreater. Energy & Fuels, 36(15), 8274-8287
Open this publication in new window or tab >>Derivatizing of Fast Pyrolysis Bio-Oil and Coprocessing in Fixed Bed Hydrotreater
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2022 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 36, no 15, p. 8274-8287Article in journal (Refereed) Published
Abstract [en]

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

Place, publisher, year, edition, pages
American Chemical Society, 2022
Keywords
Chemical reactors, Dewatering, Distillation, Fatty acids, Gas oils, Liquids, Petroleum refining, Coprocessing, Fast pyrolysis bio-oil, Fixed bed, Fixed bed reactor, Fixed-bed reactors, Hydrotreaters, Hydrotreatment, Light gasoils, Liquid products, Tall oil fatty acids, Fluid catalytic cracking
National Category
Chemical Process Engineering
Identifiers
urn:nbn:se:ri:diva-60177 (URN)10.1021/acs.energyfuels.2c01608 (DOI)2-s2.0-85136171355 (Scopus ID)
Note

Funding details: Energimyndigheten, Dnr 2017-010695, P45131-1; Funding text 1: The Swedish Energy Agency through project P45131-1 (Dnr 2017-010695) is gratefully acknowledged for financial support of parts of the development work. We also thank all colleagues within RISE and Preem who have contributed with ideas and recommendations during the project work.

Available from: 2022-09-29 Created: 2022-09-29 Last updated: 2024-05-17Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0009-0000-6482-3178

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