Recovering valuable products from the aqueous streams of fast pyrolysis

Hall, Patrick H.

doi:10.31274/etd-180810-5770

Cited by 1 publication

(2 citation statements)

References 61 publications

(81 reference statements)

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“…The inline catalytic treatment lost carbon to coke on the catalyst and reduced the recovery of producer gas carbon in the form of condensable bio-oil and aqueous phase. The latter is usually considered as wastewater since the recovery of the dissolved oxygenates from the aqueous phase is challenging, but research is ongoing in this field [57][58][59][60]. By taking nitrogen as an internal standard for the sampling of the producer gas slip stream, the carbon yields with respect to the total fed biomass could be calculated (see Table S8).…”

Section: Product Distribution and Bio-oil Qualitymentioning

confidence: 99%

Catalytic upgrading of tars generated in a 100 kWth low temperature circulating fluidized bed gasifier for production of liquid bio-fuels in a polygeneration scheme

Eschenbacher

Jensen

Henriksen

et al. 2020

Energy Conversion and Management

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Section: Product Distribution and Bio-oil Qualitymentioning

confidence: 99%

Catalytic upgrading of tars generated in a 100 kWth low temperature circulating fluidized bed gasifier for production of liquid bio-fuels in a polygeneration scheme

Eschenbacher

Jensen

Henriksen

et al. 2020

Energy Conversion and Management

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“…Since vapor-phase upgrading produces additional water during dehydration and hydrogenation reactions, the condensed liquid often separates into an organic-rich oil phase as the main product of interest for fuel applications and an aqueous phase. Recovering valuable products such as levoglucosan and acetic acid from the aqueous phase stream is an active field of research. − …”

Section: Introductionmentioning

confidence: 99%

A Review of Recent Research on Catalytic Biomass Pyrolysis and Low-Pressure Hydropyrolysis

2021

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Direct catalytic upgrading of biomass-derived fast pyrolysis vapors can occur in different process configurations, under either inert or hydrogen-containing atmospheres. This review summarizes the myriad of different catalysts studied and benchmarks their deoxygenation performance by also taking into account the resulting decrease in bio-oil yield compared to a thermal pyrolysis oil. Generally, catalyst modifications aim at improving the initial selectivity of the catalyst to more desirable oxygen-free hydrocarbons and/or improving the catalysts’ stability against deactivation by coking. Optimizing the pore structure and acid site density/distribution of solid acid catalysts can slow down deactivation and prolong activity. Basic catalysts such as MgO and Na2O/γ-Al2O3 are excellent ketonization catalysts favoring oxygen removal via decarboxylation, whereas solid acid catalysts such as zeolites primarily favor decarbonylation and dehydration. Basic catalysts can therefore produce bio-oils with higher H/C ratios. However, since their coke formation per surface area is higher, compared to a microporous HZSM-5 zeolite, precoking (or imperfect regeneration) of these basic catalysts and operating for longer time-on-stream can be approaches to improve the oil yield. In-line vapor-phase upgrading with a dual bed comprising a solid acid catalyst followed by a basic catalyst active in ketonization and aldol condensation further improves deoxygenation while maintaining high bio-oil carbon recovery. Also low-cost catalysts such as iron-rich red mud have deoxygenation activity. An improved bio-oil carbon recoverycompared at a similar level of oxygen removalcan be obtained when changing from an inert atmosphere to a hydrogen-containing atmosphere and using an effective hydrodeoxygenation (HDO) catalyst. To keep costs low, this can be conducted at near-atmospheric pressure conditions. Pt/TiO2 and MoO3/TiO2 showed high activity and reduced coke formation. Stable performance has been demonstrated using Pt/TiO2 for 100+ reaction/regeneration cycles with woody biomass feedstock. If future works can demonstrate the same durability for lower-cost biomass containing higher contents of ash, N, and S, this would considerably boost the commercial viability of near-atmospheric pressure HDO. Further research should be directed to testing the durability of lower-cost HDO catalysts such as MoO3/TiO2 and further improving the activity and stability of lower-cost catalysts.

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Recovering valuable products from the aqueous streams of fast pyrolysis

Cited by 1 publication

References 61 publications

Catalytic upgrading of tars generated in a 100 kWth low temperature circulating fluidized bed gasifier for production of liquid bio-fuels in a polygeneration scheme

Catalytic upgrading of tars generated in a 100 kWth low temperature circulating fluidized bed gasifier for production of liquid bio-fuels in a polygeneration scheme

A Review of Recent Research on Catalytic Biomass Pyrolysis and Low-Pressure Hydropyrolysis

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