Combustion Behavior of Single Pellets of Coal–Wood Mixtures in a Hot Gas Flow Field

Mock, Chinsung; Lee, Hookyung; Choi, Se-Weon; Yang, Won Seok; Choi, Sangmin; Manović, Vasilije

doi:10.1021/acs.energyfuels.8b02557

Cited by 12 publications

(3 citation statements)

References 48 publications

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“…There was also a hetero‐homogeneous ignition method, which referred to the simultaneous occurrence of volatiles and char ignition. Mock et al conducted single‐pellet combustion test of the mixture of coal and wood in a laboratory‐scale reactor. During the homogeneous combustion process, two modes of volatiles flame were found: partially dissociative flame and diffused flame.…”

Section: Resultsmentioning

confidence: 99%

An experimental study of single unconventional biomass pellets: Ignition characteristics, combustion processes, and artificial neural network modeling

Lin

Wang

et al. 2020

Int J Energy Res

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Summary This study applied the artificial neural networks (ANNs) model to the thermal data obtained by suspension ignition and combustion experiment of single peanut shells (PS, millimeter scale) pellet under O2/CO2 atmosphere. ANN11 was the best ANN model for predicting the relevant parameters of PS combustion. The coincidence between ANN prediction data and experimental data was over 99%. Two modes of biomass pellet ignition were observed: homogeneous ignition of volatiles and hetero‐homogeneous ignition of volatiles and char simultaneously. The ignition mode was transformed from homogeneous ignition to hetero‐homogeneous ignition when oxygen concentration was 50%. In addition, it was observed that ignition at the bottom emerged first, and then the upper end was ignited, finally generating an envelope flame. This phenomenon occurred when gas flow temperature exceeded 873 K or the oxygen concentration was greater than 50%. The reduction of ignition delay time and internal ignition temperature from 21% to 50% oxygen concentration was more intense than that of 50% to 100% oxygen concentration. Increasing oxygen concentration or temperature resulted in a shorter, brighter, and more stable volatile flame of biomass pellets, which reduced volatile burnout time. Nevertheless, the impact of gas flow rate on biomass combustion was intricate and irregular.

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Section: Resultsmentioning

confidence: 99%

An experimental study of single unconventional biomass pellets: Ignition characteristics, combustion processes, and artificial neural network modeling

Lin

Wang

et al. 2020

Int J Energy Res

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“…Only the work of D. Howard and R. Essenhigh, referred to above, notes a quantitative measure of overlap, but does not indicate how it was estimated [31]. Most papers provide a qualitative description of stage overlapping, following from visual observations or the results of mathematical modeling [38][39][40]. In this paper, we propose a technique for identifying the degree of overlapping of the char residue combustion stage with the devolatilization stage in the conversion of biomass particles.…”

Section: Combustion Mechanism Of Single Fuel Particlesmentioning

confidence: 99%

Experimental Study to Replicate Wood Fuel Conversion in a Downdraft Gasifier: Features and Mechanism of Single Particle Combustion in an Inert Channel

Svishchev

2022

Applied Sciences

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Downdraft gasification is a promising process of energy conversion of wood biomass. There are such fuel conversion conditions that differ favorably from conventional conditions. In such conditions, there is no pyrolysis zone in the fuel bed, which precedes the oxidation zone. Fuel is supplied into the oxidizing zone without charring, where it reacts with the intensive cold air flow from tuyeres. The study aims to replicate the conversion of particles in a gasifier close to tuyeres. For this purpose, the individual particles are burned in the muffle furnace space and the quartz channel replicating presence of other bed particles at a first approximation. In the experiment, the furnace temperature was varied, as well as the velocity of air supplied to the particle. Two-stage and single-stage mechanisms of particle combustion were identified. A two-stage process is observed in the range of tuyere velocities below 20 m s−1. The two-stage mechanism is characterized by a stage of devolatilization and volatiles combustion, followed by a stage of char residue combustion. The stages are predominantly separate from each other, and their degree of overlapping is low, amounting to 24%. At the tuyere velocities above 125 m s−1 combustion of particles is realized primarily as a single-stage process. The intensive air flow reaches the fuel particle surface and initiates combustion of the surface char layer. In this case, the stages of devolatilization and char residue combustion run concurrently for the most part. In the single-stage mechanism, the degree of stage overlapping is significantly higher and amounts to 60–95%. For the two-stage combustion mechanism, the effect of cyclic movement of the flame across the particle surface is evident. The number of cycles can reach eight. This effect is due to the change of conversion stages. At air velocity above 95 m s−1, fragmentation of fuel particles commences. A layer of char formed at an initial stage of burning heats up in the intensive air flow and is separated from the particle surface. The heated walls of the quartz channel contribute to the intensification of particle combustion. This effect is probably due to the swirling of the flame between the wall and the particle surface.

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“…The quality of fuel pellets is mainly determined by some important key parameters, including ash content, heating value, amount of fines, mechanical durability, and bulk density (Jenkins et al 1998;Lehtikangas 2001). The basic and most important parameters, which are well defined in the American Society for Testing Materials (ASTM) and International Organization for Standardization (ISO) standards, are used to decide the applicability of solid fuels in the market (Tarasov et al 2013;Kang et al 2018;Mock et al 2018). However, the use of PMS for energy demand and its applications are not straightforward.…”

Section: Introductionmentioning

confidence: 99%

Fuel pellets from fine paper mill sludge supplemented by sawdust and by refined recovered lubricating oil

Ahmad

Lee

Goo

et al. 2020

BioRes

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Fine paper mill sludge (FPMS) disposal has emerged as a problem since the dumping of FPMS was banned. This study investigated the effects of adding a refined recovered lubricating oil (ion-refined oil) to FPMS pellets to increase its heating value and combustion time and decrease ash content and ignition time. Fuel pellets were prepared in three conditions, C-1, C-2, and C-3. In C-1, ion-refined oil was added to FPMS to examine its burning capability. In C-2, two types of pellets were produced mixing sawdust and FPMS ratios of 25:75 and 50:50. A ratio of 50:50 was selected for C-3, to which the ion-refined oil was added in different ratios. The quality of the energy fuel pellets was determined using proximate and ultimate analyses, except for chlorine content, which was determined through liquid ion chromatography. The properties of fuel pellets were determined and compared with national standards. It was confirmed that the results for pellets at a ratio of 50:50 with 10% and 15% ion-refined oil were acceptable, because these results were comparatively similar to the standards. Finally, it was concluded that ion-refined oil was an effective additive to FPMS to increase the heating value for energy demand and lower the ash content.

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Combustion Behavior of Single Pellets of Coal–Wood Mixtures in a Hot Gas Flow Field

Cited by 12 publications

References 48 publications

An experimental study of single unconventional biomass pellets: Ignition characteristics, combustion processes, and artificial neural network modeling

An experimental study of single unconventional biomass pellets: Ignition characteristics, combustion processes, and artificial neural network modeling

Experimental Study to Replicate Wood Fuel Conversion in a Downdraft Gasifier: Features and Mechanism of Single Particle Combustion in an Inert Channel

Fuel pellets from fine paper mill sludge supplemented by sawdust and by refined recovered lubricating oil

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