Investigation into the effects of ash-free coal binder and torrefied biomass addition on coke strength and reactivity

Kim, Gyeong-Min; Lisandy, Kevin Yohanes; Isworo, Yanuar Yudhi; Kim, Jin-Ho; Jeon, Chung-Hwan

doi:10.1016/j.fuel.2017.10.077

Cited by 24 publications

(8 citation statements)

References 28 publications

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“…Not only charcoal but also torrefied biomass seems to be a better additive than dried biomass. 15,8 El-Tawil et al 14 added torrefied wood to coal blend and found that the strength index (M40) of coke and its CSR were equivalent or slightly lower than those of coke from the coal blend alone.…”

Section: Previous Studies On Production Of Coke Frommentioning

confidence: 99%

High-Strength Formed Coke from Torrefied Biomass and Its Blend with Noncaking Coal

et al. 2022

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In continuation of our previous study on production of high-strength metallurgical coke from torrefied softwood (cedar), we studied coke production from a mixture of torrefied cedar (TC) and noncaking coal by pulverization to sizes <100 μm, mixing, binderless hot briquetting, and carbonization. These sequential processes produced coke with a tensile strength of 5–17 MPa, which was equivalent to or greater than that of conventional coke (5–6 MPa), from TC-coal mixtures over the entire ranges of TC mass fraction in briquette of 0–100%, torrefaction temperature of 250–300 °C, and choice of coal (sub-bituminous or medium-volatile bituminous coal). The mixing of TC and coal hindered densification of coke due to hindrance of shrinkage of more-shrinkable TC-derived particles during the carbonization under many of the conditions. Nevertheless, positive synergy occurred in the coke strength at TC mass fractions of over 50%, where coal-derived particles were dispersed in the matrix of TC-derived particles, bonded to them during the carbonization, and behaved as a reinforcement of the matrix. The bonding between TC-derived and coal-derived primary particles was revealed by scanning electron microscopy. Copulverization of mixed TC and coal to sizes <40 μm before the briquetting gave cokes having strengths as high as 23–28 MPa. The fine pulverization increased the frequencies of mutual bonding of TC-derived particles and coal-derived particles and bonding between TC-derived and coal-derived particles per coke volume. The strength of coke from the TC-coal mixture generally followed volume-based additivity of strengths of cokes from TC and coal. This was realized by mixing primary particles of TC and coal within ≈10 μm scale or even smaller.

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Section: Previous Studies On Production Of Coke Frommentioning

confidence: 99%

High-Strength Formed Coke from Torrefied Biomass and Its Blend with Noncaking Coal

et al. 2022

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“…Utilization of many different types of additives in coke making and their influence on the modification of thermoplastic properties of coal have been subject to a wide array of experimental investigations. − ,− However, there is a noticeable scarcity of novel theoretical investigations which aim to provide a molecular-level understanding of the influence of organic additives on the development of coal fluidity. To the best of our knowledge, only recently, Hou et al have tried to shed light on the molecular mechanism of coal liquefaction employing density functional theory (DFT) calculations.…”

Section: Introductionmentioning

confidence: 99%

Deciphering the Differential Influence of Organic Additives on Coal Fluidity Development: A First-Principles Investigation

et al. 2021

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Formation of high-quality coke is essentially controlled by the development of the extended stability of the coal fluid phase during industrial carbonization processes. Stabilization of coal free radicals through hydrogenation leads to this development of coal fluidity. The donatable hydrogens are usually supplied by the donor hydrogen species formed through the thermal decomposition of a coal macromolecular network. In view of the limited reserve of the donor hydrogen species within a coal system, organic additives with characteristic hydrogen-donating ability are conventionally added to the system to maintain the desirable coal fluidity. However, the choice of compounds requires a clear understanding of their chemistry and associated reaction features. In this context, factors controlling hydrogen-donating properties of some organic donor hydrogen compounds are investigated herein within the framework of density functional theory. A mechanistic interpretation of the reaction of the compounds with the coal radical is offered. In addition to structural modification, the influence of the functional group, namely, the phenolic hydroxyl group, on the hydrogen-donating efficiency of the systems is validated through our calculations. The key role of molecular orbitals in facilitating the release of hydrogens from them is also elucidated. Thus, the work features an advanced understanding of a fundamental industrial process combining a detailed electronic description of the systems. The efficiency of a new compound to act as a superior hydrogen donor candidate is identified. The insights obtained are believed to help derive a rational understanding of the systems and structure−property relationships, which, in turn, can inspire future studies to engineer desired compounds with improved properties. The relevance of our findings to practical carbonization processes is also illustrated in the present work.

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“…2,3 Firstly, the coal becomes soft, liquefication, agglomerate, accompanied with the condensation reactions, which results in the formation of the semicoke when the coal is heated to 500 C in an inert atmosphere, 4 then the semicoke continues to undergo a series of reactions and produces metallurgical coke with a higher mechanical strength and moderate CO 2 reactivity when the temperature is increased from 500 C to 1100 C. [5][6][7] Due to the shortage and the higher price of the coke coal, the substitution of coke coal with biomass for making coke had been widely investigated. [8][9][10] There are several advantages caused by the biomass incorporation into coal for coke making. One is widening the alternative raw materials for coke making, which simultaneously reduces the price of the raw materials since the price of biomass is lower than that of the coke coal.…”

Section: Introductionmentioning

confidence: 99%

Physiochemical structure of semicoke derived from co‐carbonization of coal and sawdust blends

Qin

Zhao

Han

et al. 2021

Intl J of Energy Research

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Investigation into the effects of ash-free coal binder and torrefied biomass addition on coke strength and reactivity

Cited by 24 publications

References 28 publications

High-Strength Formed Coke from Torrefied Biomass and Its Blend with Noncaking Coal

High-Strength Formed Coke from Torrefied Biomass and Its Blend with Noncaking Coal

Deciphering the Differential Influence of Organic Additives on Coal Fluidity Development: A First-Principles Investigation

Physiochemical structure of semicoke derived from co‐carbonization of coal and sawdust blends

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