Influence of pyrolysis pressure on structure and combustion reactivity of Zhundong demineralized coal char

Lin, Dan; Liu, Li; Zhao, Yan; Zhao, Yijun; Qiu, Penghua; Xie, Xiaochen; Sun, Shaozeng

doi:10.1016/j.joei.2020.03.011

Cited by 21 publications

(7 citation statements)

References 43 publications

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“…The combustion performance of char is mainly affected by its chemical and pore structure. 47 With the increase of pyrolysis temperature, the volatile content of char decreases, causing the reduction of combustion performance. On the other hand, in the early stage of pyrolysis, with the release of water and volatile matter in the coal sample, a large number of micropores are formed.…”

Section: Results and Discussionmentioning

confidence: 99%

“…The combustion activation energies of NMH-R char, NMH-I char, and NMH-L char did not significantly change when the pyrolysis temperature was below 500 °C. The combustion performance of char is mainly affected by its chemical and pore structure . With the increase of pyrolysis temperature, the volatile content of char decreases, causing the reduction of combustion performance.…”

Section: Results and Discussionmentioning

confidence: 99%

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Effects of Vitrinite in Low-Rank Coal on the Structure and Combustion Reactivity of Pyrolysis Chars

Hong

et al. 2020

ACS Omega

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Pyrolysis is a highly promising technology for the efficient utilization of low-rank coal. The structure of coal plays an important role in its utilization. In this paper, the evolution of the char structure during heat treatment (200–800 °C) of Naomaohu coal and its different vitrinite-rich fractions was studied. The functional group structure, aromatic ring structure, and crystallite size of chars were determined by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD) spectroscopy, respectively. The results indicated that minerals inhibit the condensation reaction of aromatic rings during pyrolysis. The high vitrinite content in coal is conducive to the formation of larger char crystallite average sizes ( L a ). The relationship between L a (1.69–3.10 nm) and the Raman band area ratio A (G R +V L +V R ) / A D or A D / A all was established. In addition, the combustion performance and kinetics of chars were also investigated. The results showed that the char from high contents of the liptinite fraction has lower combustion reactivity, and demineralization treatment has significantly reduced the combustion reactivity of char.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Effects of Vitrinite in Low-Rank Coal on the Structure and Combustion Reactivity of Pyrolysis Chars

Hong

et al. 2020

ACS Omega

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“…The particle size distribution of the remaining coal types was 0–0.075 mm. AN deash coal (referred to as Dem) was prepared according to the literature 20 . Both Raw and Dem were dried at 105 °C for 12 h and then stored in a sealed state.…”

Section: Methodsmentioning

confidence: 99%

“…AN deash coal (referred to as Dem) was prepared according to the literature. 20 Both Raw and Dem were dried at 105 °C for 12 h and then stored in a sealed state. Char was obtained by pyrolysis in N 2 atmosphere at 900 °C for 2 h. Tables 2 and 3 summarize the industrial analysis of Raw, elemental analysis and sulfur morphology of the samples and the ash composition of AN prepared at 900 °C, respectively.…”

Section: Experimental Materialsmentioning

confidence: 99%

Experimental study of CaS preparation from lignite‐reduced phosphogypsum in a fluidized bed

Wang

2022

J of Chemical Tech & Biotech

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BACKGROUND: Phosphogypsum (PG) is a solid waste. For a fluidized bed, current research has focused on the preparation of CaO and SO 2 by PG decomposition, while less research has been conducted with calcium sulfide (CaS) as the target product. Therefore, the effect of different conditions on the preparation of CaS by coal reduction of PG was investigated in a fluidized bed. The mechanism of the reaction between coal and PG was revealed through experiments and kinetic calculations.RESULTS: PG decomposition is a combination of solid-solid reaction (carbon reacting with CaSO 4 ) and gas-solid reaction (reducing gas reacting with CaSO 4 ), among which the solid-solid reaction plays a major role. A PG decomposition rate of 99.42% and CaS yield of 91.55% are obtained at 850 °C for 60 min when the Ca/C molar ratio is less than 0.25 and coal particle size is less than 0.075 mm. Lignite, bituminous coal and anthracite can promote the decomposition of PG. However, the higher viscosity of bituminous coal can lead to molten coking of the product, while anthracite is less economical, so lignite is the most suitable. Minerals in coal can improve the decomposition rate of PG. A fluidized bed improves the PG decomposition rate compared to a fixed bed.CONCLUSIONS: CaS is obtained by combined solid-solid and gas-solid reactions. Decreasing the Ca/C ratio and coal particle size as well as controlling the reaction temperature below 850 °C are beneficial for CaS generation. The minerals in coal can reduce the PG decomposition temperature and increase the PG decomposition rate.

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“…The structure of the coal char undergoes significant changes, such as expansion and deformation, during the devolatilization of coal. The structure of coal char is mainly dependent on changes in heating conditions such as temperature, heating rate, and pressure . The effect of pressure on the pyrolysis process of coal is mainly manifested in two aspects, one is that the volatile fraction stays longer in the coal and its release is inhibited and the other is that the diffusion of the volatile fraction inside the coal particles increases, which obviously increases the secondary reaction .…”

Section: Introductionmentioning

confidence: 99%

Effects of Pressurized Pyrolysis on the Chemical and Porous Structure Evolution of Coal Core during Deep Underground Coal Gasification

Niu,

Xin,

Cheng

et al. 2023

ACS Omega

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During deep underground coal gasification, the semicoke produced by the pyrolysis of dense coal cores is an important material for its gasification and combustion. In this paper, pressurized pyrolysis experiments were carried out on dense coal cores at 700 °C and pressures of 1, 2, and 3 MPa using a shaft furnace. The resulting semicoke and raw coal were analyzed using the characterization methods such as the N2 isothermal adsorption/desorption and scanning electron microscopy, Fourier transform infrared spectrometry (FTIR), and a pressurized thermogravimetric analyzer coupled with a FTIR spectrometer. The pyrolysis gas generation characteristics during pressurized pyrolysis were studied. The mechanisms of evolution of aliphatic functional groups and pore structures in semicoke during pressurized pyrolysis were revealed. The results indicate that the increase in pressure obviously changed the gas composition, most notably, the relative content of CH4 and H2 in the pyrolysis gas. The methane in the pyrolysis gas during pressurized pyrolysis of dense coal cores is mainly from the secondary reaction. As the pyrolysis pressure increased, the ratio of –CH2–/–CH3 became smaller, indicating that the pressure promoted the breakage of the long fat chains. With the increase of the pyrolysis pressure, the surface deformation of pressurized pyrolysis semicoke increases, and the pore structure becomes more abundant.

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Influence of pyrolysis pressure on structure and combustion reactivity of Zhundong demineralized coal char

Cited by 21 publications

References 43 publications

Effects of Vitrinite in Low-Rank Coal on the Structure and Combustion Reactivity of Pyrolysis Chars

Effects of Vitrinite in Low-Rank Coal on the Structure and Combustion Reactivity of Pyrolysis Chars

Experimental study of CaS preparation from lignite‐reduced phosphogypsum in a fluidized bed

Effects of Pressurized Pyrolysis on the Chemical and Porous Structure Evolution of Coal Core during Deep Underground Coal Gasification

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