Effect of Hydrothermal Dehydration on the Slurry Ability of Lignite

Sun, Meijie; Zheng, J. P.; Li, Xiangyang

doi:10.1021/acsomega.1c00639

Cited by 8 publications

(5 citation statements)

References 23 publications

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“…The coal gasification fine slag, named as XFS, was procured from a typical entrained-flow coal gasification plant in Xinjiang, China. Because the moisture content of the initial XFS was 56.91%, the experimental samples were dried at 105 °C for 6 h and subsequently air dried for 12 h. The proximate analysis , and high heating value of XFS was presented in Table . The fixed carbon content of XFS was as high as 31.78%, indicating its potential recovery value for the coal gasification plants.…”

Section: Methodsmentioning

confidence: 99%

Enrichment of Residual Carbon in Coal Gasification Fine Slag via Wet Sieving Separation with Ultrasonic Pretreatment

Sun

Liu

et al. 2022

ACS Omega

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To overcome the environmental and economic challenges posed by the increasing amounts of the coal gasification slag, here, a simple and efficient method for enriching the residual carbon from the coal gasification fine slag was proposed. The residual carbon enrichment pattern in the particle size distribution of coal gasification fine slags after the ultrasonic pretreatment was mainly enriched toward the 500–250 μm and 250–125 μm particle size classes by analyzing the changes in the particle size distribution and apparent morphology. The pulp pretreatment at the ultrasonic output power of 270 W for 4 min was determined as the optimal experimental condition with respect to the yield, ash content, and ash rejection of the concentrates. Compared to the conventional wet sieving separation, the yield and ash content of the final concentrates were reduced by 7.99 and 14.96%, respectively. Moreover, the ash rejection of the final concentrates was as high as 88.51%, indicating an increment of 11.63% than the conventional wet sieving separation. Furthermore, thermogravimetric analysis confirmed that the final concentrates exhibited the lowest reactivity; however, these demonstrated had the highest carbon content (nearly 70%) with 27.27% ash content. The combustion characteristics analysis showed that the wet screening concentrate after ultrasonic pretreatment had the highest composite combustion characteristic index (S) of 3.17 × 10–8, as compared to the raw and conventional sieving concentrates.

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Section: Methodsmentioning

confidence: 99%

Enrichment of Residual Carbon in Coal Gasification Fine Slag via Wet Sieving Separation with Ultrasonic Pretreatment

Sun

Liu

et al. 2022

ACS Omega

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“…The apparent reaction rate coefficient is given by eq 17. where η is the effectiveness factor, γ is the characteristic size of the particle (m), ρ p is the density of the particle (kg/m 3 ), A 0 is the frequency factor, A 0 = 8.6 × 10 2 (kg/m 2 /s/atm), E a is the activation energy, E a = 150,000 (kJ/mol), 31 and R u is the gas constant with the value of 8.314 (J/K/mol). The apparent reaction rate coefficient is given by eq 18. where M C is the molecular weight of carbon, R is the gas constant with the value of 82.06 (cm 3 •atm/mol/K), Sh is the Sherwood number (Sh = 2 32,33 ), and D ref is the reference value of the diffusion coefficient. 4.3.6.…”

Section: Conservation Equationsmentioning

confidence: 99%

“…With the rapid growth in the economy and an increase in energy requirement, coal is still the dominant energy resource . The combustion of lignite has gradually attracted attention because it is low-grade coal with the advantages of low mining cost, rich reserves, high content of volatile matter, and low amount of pollution-forming elements. − However, the utilization of lignite is limited due to its disadvantage of high moisture content and low calorific value . The moisture content of lignite in China is generally 25–40%, while the moisture content of lignite mined in Australia’s Latrobe valley can be as high as 55–70% .…”

Section: Introductionmentioning

confidence: 99%

Effects of Moisture on the Ignition and Combustion Characteristics of Lignite Particles: Modeling and Experimental Study

Bai

et al. 2022

ACS Omega

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The influence of the moisture content on the ignition and combustion characteristics of lignite single particles was studied using an ignition model of single coal particles with moisture and experimental investigations in a visual drop tube furnace under the temperature of 1300 K. The moisture content and the lignite particle size were varied within the ranges of 0–20% and 75–250 μm, respectively. The images of the combustion process illustrated that higher moisture content caused a significant ignition delay. The probability of homogeneous ignition was greatest when the particle size was 125–150 μm and the moisture content was 5%. An ignition model was employed to explain the mechanism of the influence of moisture content on the ignition and combustion characteristics, which embedded the chemical percolation devolatilization model to increase the accuracy of predictions. The predicted results show that there was an overlap in the release of moisture and volatile matter from the lignite particle during the combustion at a high heating rate. The devolatilization rate increases with the increase of moisture, which explains the increase in the probability of homogeneous ignition and fragmentation. Both particle size and moisture content have two-sided effects on the ignition mode, which causes the complexity and irregularity of the ignition mode of particles with moisture.

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“…Brown coal, known as lignite and sub-bituminous coal are classified as LRC due to the short formation time and low-grade metamorphism. Both have relatively low heat value and high ash content [11]. In addition, LRC, especially brown coal has a high moisture content, in the range of 25-65%, most of which exists as free water that rapidly evaporates under dry conditions [12].…”

Section: Lrc Types and Propertiesmentioning

confidence: 99%

Low-Rank Coal as a Source of Humic Substances for Soil Amendment and Fertility Management

et al. 2021

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Humic substances (HS), as important environmental components, are essential to soil health and agricultural sustainability. The usage of low-rank coal (LRC) for energy generation has declined considerably due to the growing popularity of renewable energy sources and gas. However, their potential as soil amendment aimed to maintain soil quality and productivity deserves more recognition. LRC, a highly heterogeneous material in nature, contains large quantities of HS and may effectively help to restore the physicochemical, biological, and ecological functionality of soil. Multiple emerging studies support the view that LRC and its derivatives can positively impact the soil microclimate, nutrient status, and organic matter turnover. Moreover, the phytotoxic effects of some pollutants can be reduced by subsequent LRC application. Broad geographical availability, relatively low cost, and good technical applicability of LRC offer the advantage of easy fulfilling soil amendment and conditioner requirements worldwide. This review analyzes and emphasizes the potential of LRC and its numerous forms/combinations for soil amelioration and crop production. A great benefit would be a systematic investment strategy implicating safe utilization and long-term application of LRC for sustainable agricultural production.

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Effect of Hydrothermal Dehydration on the Slurry Ability of Lignite

Cited by 8 publications

References 23 publications

Enrichment of Residual Carbon in Coal Gasification Fine Slag via Wet Sieving Separation with Ultrasonic Pretreatment

Enrichment of Residual Carbon in Coal Gasification Fine Slag via Wet Sieving Separation with Ultrasonic Pretreatment

Effects of Moisture on the Ignition and Combustion Characteristics of Lignite Particles: Modeling and Experimental Study

Low-Rank Coal as a Source of Humic Substances for Soil Amendment and Fertility Management

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