Catalytic decomposition of biomass tars: The impact of wood char surface characteristics on the catalytic performance for naphthalene removal

Nestler, F.; Burhenne, Luisa; Amtenbrink, Meike Juliane; Aicher, T.

doi:10.1016/j.fuproc.2016.01.020

Cited by 61 publications

(37 citation statements)

References 35 publications

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“…Greensfelder et al [11] reported that the biomass char converts the tar into free radical by removing the hydrogen. The active free radicals undergo heavy polymerization reactions that produce coke deposited on the char surface [12]. In general, the severity of coke formation can be related to the number of rings in the tar component as stated by Hosokai et.…”

Section: Introductionmentioning

confidence: 98%

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Impact of Char Properties and Reaction Parameters on Naphthalene Conversion in a Macro-TGA Fixed Char Bed Reactor

et al. 2019

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Catalytic tar removal is one of the main challenges restricting the successful commercialization of biomass gasification. Hot gas cleaning using a heterogeneous catalyst is one of the methods used to remove tar. In order to economically remove tar, an efficient low-cost catalyst should be applied. Biomass char has the potential to be such a catalyst. In this work, the reactor parameters that affect the conversion of a model tar component “naphthalene” were investigated employing an in situ thermogravimetric analysis of a fixed bed of biomass char. The following reactor and catalyst parameters were investigated: bed temperature (750 to 900 °C), gas residence time in the char bed (0.4 to 2.4 s), char particle size (500 to 1700 μm), feed naphthalene concentration, feed gas composition (CO, CO2, H2O, H2, CH4, naphthalene, and N2), char properties, and char precursor. It was found that the biomass char has a high activity for naphthalene conversion. However, the catalytic performance of the biomass char was affected by the gasification reactions that consumed its carbon, and the coke deposition that reduced its activity. Furthermore, high ash and iron contents enhanced char activity. The results of this work will be used in the design of a process that uses biomass char as an auto-generated catalyst in the gasification process.

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Section: Introductionmentioning

confidence: 98%

“…al. [12]. However, Tenser et al found that naphthalene is, specifically, the highest in terms of coke formation.…”

Section: Introductionmentioning

confidence: 98%

Impact of Char Properties and Reaction Parameters on Naphthalene Conversion in a Macro-TGA Fixed Char Bed Reactor

et al. 2019

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“…Nowadays, chars are considered as wastes and the additional costs required for their disposal decrease the economic viability of the pyrogasification process. For this reason, new routes for char valorization are studied: soil amendment and fertilizer [3], sorbent for water treatment [4] and gas cleaning [5], catalyst [6,7] and catalyst support [8] for gas treatment. The syngas produced by pyrogasification is mainly composed of permanent gases, such CO, H 2 , CO 2 , CH 4 and small hydrocarbons (C 2 -C 3 ).…”

Section: Introductionmentioning

confidence: 99%

H2S removal from syngas using wastes pyrolysis chars

Hervy

Minh

Gérente

et al. 2018

Chemical Engineering Journal

104

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A B S T R A C TPyrolysis chars from wastes were investigated as sorbents for H 2 S removal from syngas. The H 2 S removal tests were performed at ambient temperature in various dry gas matrices (N 2 , Air, Syngas) to study the effect of the gas composition on the adsorption efficiency. Two chars were produced by the pyrolysis of: used wood pallets (UWP), and a 50/50% mixture of food waste (FW) and coagulation-flocculation sludge (CFS). The chars were functionalized by low-cost processes without chemicals: gas phase oxygenation and steam activation. Activated chars were the most efficient materials due to their large specific surface area, alkaline pH, basic O-containing groups and structural defects in graphene-like sheets. Raman analysis evidenced that inherent mineral species (especially Ca and Fe) increased the H 2 S removal efficiency by promoting the formation of metal sulfide and metal sulphate species at the char surface. Mesopores lower than 70 Å were revealed to be important adsorption sites. Under dry Syngas matrix, the chars remained efficient and selective toward H 2 S removal despite the presence of CO 2 , while O 2 in the Air matrix decreased their removal capacity due to the formation of sulfur acid species. The most efficient material was the steam activated char from FW/CFS, with a removal capacity of 65 mg H2S .g −1 under dry syngas. This char was proved to be completely regenerated with a thermal treatment under N 2 at 750°C. This study demonstrated that activated chars from food waste and sludge could be used as eco-friendly, affordable, and selective materials for syngas desulfurization even under dry atmosphere.

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“…Biochars appear to be promising materials for many applications such as soil amendment, fuel, sorbent, support for catalyst, catalyst, electrochemistry, water treatment, gas cleaning, additives in anaerobic digestion, etc. [1][2][3][4][5][6][7][8][9]. Among these possible outcomes, energy applications, where biochar acts as a catalyst, are of great interest [10].…”

Section: Introductionmentioning

confidence: 99%

Advanced characterization unravels the structure and reactivity of wood-based chars

Berhanu

Hervy

Weiss-Hortala

et al. 2018

Journal of Analytical and Applied Pyrolysis

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This study aims at understanding the structural changes occurring in the carbonaceous matrix of wood-based chars during their thermal conversion. Although chars are routinely characterized by porosity measurements or scanning electron microscopy, the composition and structure of the carbonaceous matrix is often not investigated. Here, advanced characterization using X-ray synchrotron microtomography, transmission electron microscopy, Raman spectroscopy and X-ray diffraction provided a precise description of the char properties, allowing for an accurate discussion of their catalytic properties. Two chars were produced by slow pyrolysis of wood waste (400 and 700°C) and a third one was fabricated by activation under steam at 850°C of the char obtained at 700°C. The results show that the pyrolysis temperature and the activation performed did not affect the macrostructure of the chars and that the pores were interconnected at the macroscopic scale. However, at 700°C, the micro-and nanostructures were modified: short-range organized graphene fringes were observed. The activated char showed a homogeneous microstructure similar to that of its precursor. Besides, the ratio of graphene-like structures, the local organization of graphene sheets, and the imperfections in graphene-like sheets were clearly improved by the post-treatment. To our knowledge, this is the first time that such an approach, combining various tools, is applied for the study of pyrolysis chars.

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Catalytic decomposition of biomass tars: The impact of wood char surface characteristics on the catalytic performance for naphthalene removal

Cited by 61 publications

References 35 publications

Impact of Char Properties and Reaction Parameters on Naphthalene Conversion in a Macro-TGA Fixed Char Bed Reactor

Impact of Char Properties and Reaction Parameters on Naphthalene Conversion in a Macro-TGA Fixed Char Bed Reactor

H2S removal from syngas using wastes pyrolysis chars

Advanced characterization unravels the structure and reactivity of wood-based chars

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