Coal char particle secondary fragmentation in an entrained-flow coal-water slurry gasifier

Guo, Qinghua; Zhang, Zhiqing; Xue, Zhicun; Gong, Yan; Yu, Guangsuo; Wang, Fuchen

doi:10.1016/j.joei.2018.04.001

Cited by 13 publications

(4 citation statements)

References 29 publications

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“…Numerical simulation plays a pivotal role in optimizing the gasification process. For instance, Guo et al [23] investigated how the oxygen-to-carbon ratio affects particle size distribution during gasification. Watanabe et al [24] studied the impact of the oxygen-to-coal ratio on synthesis gas composition, carbon conversion rate, and cold gas efficiency.…”

Section: Introductionmentioning

confidence: 99%

A Gasification Technology to Combine Oil Sludge with Coal–Water Slurry: CFD Analysis and Performance Determination

Wu,

Yu,

et al. 2024

FDMP

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The development of more environment-friendly ways to dispose of oil sludge is currently regarded as a hot topic. In this context, gasification technologies are generally seen as a promising way to combine oil sludge with coal-water slurry (CWS) and generate resourceful fuel. In this study, a novel five-nozzle gasifier reactor was analyzed by means of a CFD (Computational fluid dynamic) method. Among several influential factors, special attention was paid to the height-to-diameter ratio of the gasifier and the mixing ratio of oil sludge, which are known to have a significant impact on the flow field, temperature distribution and gasifier performances. According to the numerical results, the optimal height-to-diameter ratio and oil mixing ratio are about 2.4:1 and 20%, respectively. Furthermore, the carbon conversion rate can become as high as 98.55% with the hydrolysis rate reaching a value of 53.88%. The consumption of raw coal and oxygen is generally reduced, while the effective gas production is increased to 50.93 mol/%.

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Section: Introductionmentioning

confidence: 99%

A Gasification Technology to Combine Oil Sludge with Coal–Water Slurry: CFD Analysis and Performance Determination

Wu,

Yu,

et al. 2024

FDMP

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“…It has attracted considerable attention in scientific research and the large operating load of a single gasifier. 2,3 The distinct characteristic of entrained-flow gasification is that it will produce a large amount of slag, which forms a slag layer of the gasifier, reducing the heat loss and helping to improve the efficiency of the entrained-flow gasifier. However, excessive accumulation of slag can cause the gasifier to clog, reducing the operating efficiency of the gasifier.…”

Section: Introductionmentioning

confidence: 99%

“…It is widely used in chemical and energy production. It has attracted considerable attention in scientific research and the large operating load of a single gasifier. , …”

Section: Introductionmentioning

confidence: 99%

Study of the Deposition Characteristics of Particles on the Slag Wall of a Gasifier

Bai

Song

Wei

et al. 2023

Ind. Eng. Chem. Res.

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In this work, the behavior of coal char particles adhering to the slag wall was studied. The effects of slag thickness and particle size on the restitution coefficient and probability of deposition were mainly discussed. In addition, the types of particle deposition were also classified. The results of exploring the effect of particle size on the coefficient of restitution show that the restitution coefficient of coal char particles hitting the slag wall surface has a complex dimensional effect, with a maximum and minimum coefficient of restitution occurring at the same particle size, a phenomenon referred to in this paper as the discrete effect. The minimum restitution coefficient greater than 0 is regarded as the critical restitution coefficient (ε f), and it is considered that particles with theoretical restitution coefficient higher than εf will bounce off the slag wall. With the particle diameter of 600 μm as the boundary, ε f first decreases and then increases. The maximum restitution coefficient increases with an increasing particle size of less than 600 μm and stays at a maximum value of 0.62 when the particle size is more than 600 μm. Moreover, the fragmentation of particles occurs at the particle size of 840–1600 μm. The discrete effect was also observed in the experimental data for the investigation of slag thickness, ε f increases with the increase of the slag thickness, and the maximum possible restitution coefficient does not change with the thickness of the slag. In addition, according to the statistics of the deposition probability, it is found that the smaller the particle size, the greater the deposition probability, the thicker the slag thickness, and the easier it is to deposit.

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“…What is more, none of the above studies have considered the effect of slag porosity on solidification characteristics. However, the devolatilization and combustion gasification reactions as well as slag droplet collision and adhesion could cause pores in molten slag droplets. − …”

Section: Introductionmentioning

confidence: 99%

Numerical Simulations of Solidification Characteristics of Molten Slag Droplets in Radiant Syngas Coolers for Entrained-Flow Coal Gasification

et al. 2021

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The high-temperature syngas and molten slag droplets discharged from entrained-flow coal gasifiers contain a large amount of heat energy, which can be efficiently recovered by radiant syngas coolers (RSCs). However, it is hard to know the solidification degree of molten slag droplets at the outlet of an RSC during industrial operations. In this work, the industrial-scale RSC and molten slag droplet models are established to predict the solidification degree of slag droplets at the outlet of the RSC. Then, the effects of slag diameter, syngas flow field, slag initial temperature, slag porosity, and slag pore structure are investigated by numerical simulations, and residence time as well as complete solidification time are calculated by coupling of a discrete-phase model and a solidification model. The results indicate that as the slag droplet diameter increases, the residence time of the slag droplet shortens, but the complete solidification time increases. When the slag droplet diameter is greater than or equal to 3.0 mm, the complete solidification time is larger than the residence time, and the slag droplet cannot solidify completely at the outlet of the RSC. The solidification degree in the windward zone is greater than that in the leeward zone. Although the slag initial temperature has little effect on the solidification, a lower slag initial temperature is still conducive to a greater solidification degree. Additionally, the pore structure facilitates solidification, and the promoting effect of penetrated pores is more remarkable than that of closed pores. A larger porosity is also beneficial to accelerate the solidification of molten slag droplets and increase the solidification degree.

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Coal char particle secondary fragmentation in an entrained-flow coal-water slurry gasifier

Cited by 13 publications

References 29 publications

A Gasification Technology to Combine Oil Sludge with Coal–Water Slurry: CFD Analysis and Performance Determination

A Gasification Technology to Combine Oil Sludge with Coal–Water Slurry: CFD Analysis and Performance Determination

Study of the Deposition Characteristics of Particles on the Slag Wall of a Gasifier

Numerical Simulations of Solidification Characteristics of Molten Slag Droplets in Radiant Syngas Coolers for Entrained-Flow Coal Gasification

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