Deactivation of a CoMo Catalyst during Catalytic Hydropyrolysis of Biomass. Part 2. Characterization of the Spent Catalysts and Char

Stummann, Magnus Zingler; Høj, Martin; Davidsen, Bente; Hansen, Lars P.; Beato, Pablo; Gabrielsen, Jostein; Jensen, Peter Arendt; Jensen, Anker Degn

doi:10.1021/acs.energyfuels.9b02585

Cited by 13 publications

(22 citation statements)

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“…Stummann et al also found that CoMo catalyst could promote the occurrence of direct deoxygenation of phenols with the lowest content of carbon after the catalytic hydropyrolysis process. In their follow-up research, Stummann et al , studied the coking and deactivation process of the CoMo catalyst and reported the catalytic effect on the products during the semicontinuous operation. A significant increase in the oxygen content of the organic phase in the bio-oil production was found after 5 days of intermittent operation without renewing the catalyst, indicating that the CoMo catalyst gradually lost its catalytic performance.…”

Section: Biomass Catalytic Pyrolysismentioning

confidence: 99%

A Review of Recent Advances in Biomass Pyrolysis

et al. 2020

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Pyrolysis has created many (and will open more) possibilities for high-value utilization of biomass. To obtain the optimal amount of desired pyrolysis products, especially high-quality bio-oil, a great deal of effort has been conducted in both academia in the past few decades, to clarify fundamental mechanisms of biomass pyrolysis and design efficient relevant technical processes. This paper comprehensively reviews recent advances in both fundamental studies and technology applications of biomass pyrolysis. First, pyrolysis mechanisms of real biomass and its major components, the reactor-scale simulation of biomass pyrolysis, and applications of pyrolysis products are discussed. Then, according to the requirements imposed to improve the physicochemical properties of respective pyrolysis products, relevant optimization and regulation methods for biomass pyrolysis process are reviewed. Previous research has indicated that biomass copyrolysis with other feedstock can not only enhance physicochemical properties of pyrolysis products but also effectively realize recycling of wastes. Thus, an in-depth discussion of recent advances in biomass copyrolysis with four different feedstocks (i.e., coal, plastics, tires, and sludge) is covered in this Review. As an indispensable component of general biomass pyrolysis, recent activities of catalytic biomass pyrolysis are also summarized, including new catalytic pyrolysis processes such as catalytic hydropyrolysis and catalytic copyrolysis. Besides, two novel heating approaches (microwave heating and solar heating) for biomass pyrolysis are described, and their features are compared with the conventional heating method. Finally, this Review is concluded with perspectives for future directions of biomass pyrolysis.

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Section: Biomass Catalytic Pyrolysismentioning

confidence: 99%

A Review of Recent Advances in Biomass Pyrolysis

et al. 2020

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“…32 Therefore it is certain that some deactivation of the catalyst in the HDO reactor has taken place. The catalyst in the fluid bed reactor operates under more harsh conditions and has also been partly deactivated due to carbon deposition and uptake of potassium as will be discussed in detail in part 2 of this work (see ref 35). It is possible to regenerate some of the catalyst activity lost due to coking, 29 while catalyst deactivation due to metals deposited on the catalyst are less reversible 53 and thus of greater concern.…”

Section: (B) the Density At 40mentioning

confidence: 99%

“…Secondly, the effect of poisoning the catalyst by doping it with potassium, in the form of K 2 CO 3 , was studied. In this work (part 1) we report detailed product characterization including the composition of the condensed liquids, while in part 2 35 we characterize the spent catalysts and the produced char in detail. This is to our knowledge the first study in the open literature where the effect of the time on stream on catalytic hydropyrolysis with a well-defined catalyst is tested and the effect of potassium on the catalytic activity in catalytic hydropyrolysis of biomass is investigated.…”

Section: Introductionmentioning

confidence: 99%

Deactivation of a CoMo Catalyst during Catalytic Hydropyrolysis of Biomass. Part 1. Product Distribution and Composition

et al. 2019

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10 Deactivation of a sulfided CoMo/MgAl 2 O 4 catalyst during fluid bed catalytic hydropyrolysis of biomass 11 (beech wood) was studied. The stability of the catalyst was investigated by converting approximately 4.4 kg 12 of biomass and collecting the liquid and solid products for every 1 kg fed, using the same catalyst load. The 13 total time on stream was 16.2 h. A secondary hydrotreating reactor with a sulfided NiMo/Al 2 O 3 catalyst was 14 used after the fluid bed to further deoxygenate the vapors. The condensed organics and C 4+ gasses yield for 15 each 1 kg fed was 22.2 ± 1 wt.%, which was variations within the experimental uncertainty. The CO and CO 2 16 yield during the experiment increased from 14.9 to 18.2 wt.% daf, while the aqueous phase yield decreased 17 from 38.0 to 35.1 wt.% daf from the first to the fifth kilogram fed. The change in CO, CO 2 , and aqueous 18 phase yields was ascribed to a decrease in hydrodeoxygenation activity of the used catalysts. The 19 concentration of oxygen in the condensed organic phase increased from 40 to 2832 ppm, indicating that 20 deactivation of the catalyst in both the fluid bed and the HDO reactor occurred. Our previous study 1 has 21 shown that potassium, a known catalyst poison, is transferred from the beech wood to the catalyst, and the 22 effect of doping the catalyst with 1.9 wt.% potassium was therefore also investigated. The results were 23 compared to a similar experiment with a fresh catalyst. Both experiments were performed without the

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“…129 This indicates a very high mobility of K, while Ca was mainly found as larger particles on the spent catalysts. 130 Replacing the complete inventory of expensive zeolite catalyst after 10−20 days of operation makes in-situ CFP with zeolite-based catalysts commercially less attractive, although regeneration by washing in a mild acidic solution may be possible while adding operational costs. 438 Noble metals such as Pt and transition metals like Cu and especially Ni may also be deactivated by sulfur (S) species such as H 2 S, RSH, RSSR, etc., via formation of sulfides, which are difficult to remove due to the formation of a strong metal-S bond.…”

Section: Deactivationmentioning

confidence: 99%

“…50,125−129 Also with HDO catalysts where acidity is not necessarily important, alkali metal may deactivate the catalyst. 130,131 In addition, the separation of char and catalyst fines may be challenging. In ex-situ CFP and CFHP, the ash-rich char can be separated by hot gas filtration, thereby preventing direct contact of biomass ash species with the catalyst, greatly reducing the risk of catalyst poisoning.…”

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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Deactivation of a CoMo Catalyst during Catalytic Hydropyrolysis of Biomass. Part 2. Characterization of the Spent Catalysts and Char

Cited by 13 publications

References 56 publications

A Review of Recent Advances in Biomass Pyrolysis

A Review of Recent Advances in Biomass Pyrolysis

Deactivation of a CoMo Catalyst during Catalytic Hydropyrolysis of Biomass. Part 1. Product Distribution and Composition

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

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