A DEM modeling of biomass fast pyrolysis in a double auger reactor

Qi, Fenglei; Wright, Mark Mba

doi:10.1016/j.ijheatmasstransfer.2020.119308

Cited by 24 publications

(11 citation statements)

References 54 publications

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“…46 The main sewage sludge pyrolysis products are syngas (including CO, H 2 , CO 2 , CH 4 (and other hydrocarbons) and condensable compounds), bio-oil, and carbonaceous residue (char). 3,15,24,27,28,54,55,57,60 These products can be used as fuel or functional materials. 15 Please refer to Figure 2 for more details.…”

Section: Sewage Sludge Pyrolsyismentioning

confidence: 99%

Pyrolysis of Municipal Sewage Sludge for Biofuel Production: A Review

Djandja

Wang

et al. 2020

Ind. Eng. Chem. Res.

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Among the various problems the world is facing, two problems are addressed in this paper. On the one hand, biomass, the fourth largest and most important renewable energy option that can provide different forms of energy, is criticized because it competes, sometimes, with the food chain. On the other hand, the amount of municipal sewage sludge has continued to increase over the years, and its disposal remains a crucial point of discussion between urban planners, wastewater managers, and leaders of environmental protection. To address this problem, researchers are directing their focus toward alternatives to conventional biomass resources, such as organic wastes and residues. Thus, municipal sewage sludge is a likely candidate for energy and high-value added material production. Regarding this issue, one of the main methods proposed by researchers is the pyrolysis process. The aim of this paper is to review the research conducted on sewage sludge conversion through the pyrolysis process. After characterizing municipal sewage sludge, we present a summary of the sewage sludge pyrolysis process. Then, the effects of some of the most influential parameters are examined. The last main part of this work is dedicated to the nitrogen transformation pathway during this process.

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Section: Sewage Sludge Pyrolsyismentioning

confidence: 99%

Pyrolysis of Municipal Sewage Sludge for Biofuel Production: A Review

Djandja

Wang

et al. 2020

Ind. Eng. Chem. Res.

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“…Hu et al 25 also chose CFD-DEM to study the influence of biomass shrinkage and superficial gas velocity on biomass pyrolysis. Qi and Wright 26 simulated biomass fast pyrolysis in a double auger reactor and analyzed the evolution of the biomass decomposition rate. Ku et al 27 combined CFD-DEM with a thermally thick particle model to explore the pyrolysis performance of larger biomass particles in a fluidizedbed reactor.…”

Section: Introductionmentioning

confidence: 99%

Impact of the Reactor Structure on Biomass Pyrolysis in Fluidized-Bed Reactors: A Coarse-Grained CFD-DEM Study

Wang

Lin

et al. 2021

Energy Fuels

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A coarse-grained computational fluid dynamics coupled with the discrete element method (CFD-DEM) model, combined with a smoothed voidage algorithm and a multicomponent and multistep pyrolysis scheme, has been developed, validated, and used to study biomass pyrolysis in different-shaped fluidized-bed reactors. Correspondingly, fluidized-bed reactors with three different section shapes (i.e., circular, square, and rectangular sections) and gas inlet areas (i.e., 25, 50, and 100% of the bottom section) were devised to explore the effect of the reactor structure on pyrolysis behavior. The simulation results have been extensively analyzed and discussed by various indicators, such as the gas–solid flow patterns, bubble behaviors, pyrolysis product species, biomass reaction rates, and reactor wall erosion depths. It is found that the circular reactor has the largest mean bed height but the lowest fluctuation frequency. Moreover, the circular reactor generally has the largest bubble equivalent diameter at the same height, followed by the square reactor, and the rectangular reactor provides the smallest bubbles. Regarding the effect of the gas inlet area, the fluctuation frequency monotonically increases with reducing the gas inlet area. The largest gas inlet gives the lowest biomass mass loss rate and the smallest bubble equivalent diameter, whereas the other two smaller gas inlets provide quite similar results. Moreover, decreasing the gas inlet area also generates large bubbles more frequently. Finally, the circular reactor suffers the severest wear, followed by the square and the rectangular reactors. These findings are helpful in optimizing the design and operation of biomass fluidized-bed pyrolysis processes.

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“…The experimental measurement of the heat transfer coefficient is challenging due to the dynamic nature and moving components of screw reactors. Some simulation efforts have been made by using the Eulerian method 29 or the discrete elements method 30 (DEM) to model mass and heat transfer in screw reactors. Funke et al 31 simulated heat transfer in a twinscrew auger type reactor using biomass and heat carrier material and observed its strong dependence on mixing quality and the ratio of heat carrier to biomass particles.…”

Section: Introductionmentioning

confidence: 99%

Integration of Thermal Treatment and Extrusion by Compounding for Processing Various Wastes for Energy Applications

Kolapkar

Zinchik

et al. 2021

Energy Fuels

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Waste generation is increasing, and a significant portion of the wastes is being landfilled. Torrefaction of such wastes to produce clean fuels is one of the potential solutions. This paper studied torrefaction of mixed fiber–plastic wastes at 300 °C in an integrated torrefaction–extrusion screw reactor with a throughput of up to 70 kg/h. The study experimentally measured the thermomechanical properties of the torrefaction–extrusion process and the pellets produced. The study presents the results for thermal dynamics, the effect of shaft configuration on residence time, specific mechanical energy (SME), heat transfer coefficient (U), specific heat (C) of mixed wastes, and mechanical and rheological properties of pellets. First, the thermal dynamics of the system were studied along the corresponding response of heaters with and without the flow of materials measured. The residence time measurement showed 20% and 40% cut flighting had about 2.3 and 3.7 times more residence time compared to a regular screw. The specific heat of the heterogeneous mix blend was measured at 1.58 kJ/(kg °C). The average overall heat transfer coefficient was measured experimentally for the reactor at 52.5 W/(m2 °C). The correlation between specific mechanical energy and mass flow showed more than 3 times decrease in specific energy consumed when the feed rate was increased from ∼10 to 50 kg/h. Thermomechanical analysis, flexural testing, and rheological testing were performed on the produced pellets to measure pellet properties.

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A DEM modeling of biomass fast pyrolysis in a double auger reactor

Cited by 24 publications

References 54 publications

Pyrolysis of Municipal Sewage Sludge for Biofuel Production: A Review

Pyrolysis of Municipal Sewage Sludge for Biofuel Production: A Review

Impact of the Reactor Structure on Biomass Pyrolysis in Fluidized-Bed Reactors: A Coarse-Grained CFD-DEM Study

Integration of Thermal Treatment and Extrusion by Compounding for Processing Various Wastes for Energy Applications

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