Selection of IGCC candidate coals by pilot-scale gasifier operation

Yun, Yongseung; Yoo, Young Don; Chung, Seok Woo

doi:10.1016/j.fuproc.2004.08.009

Cited by 46 publications

(22 citation statements)

References 6 publications

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“…Predicting the influence of the viscosity on the slag behaviors would be helpful in evaluating the impact of the uncertainties involved in the correlations. This is also meaningful in terms of the gasifier operation, because the ash characteristics are important parameters in determining the range of suitable coals and the amount of flux required [11].…”

Section: Effects Of Slag Properties: Viscositymentioning

confidence: 99%

“…The ash fusion temperature and slag viscosity are important properties in relation to the flowability and thickness of the liquid slag, which are determined by inherent properties such as the ash composition and chemistry, as well as external conditions such as the temperature and reaction atmosphere [5][6][7][8][9]. In order to minimize slag-related problems, coals with ash content and properties within an appropriate range should be selected [10,11]. For coals with high or low slag viscosity, additional supply of CaO-based flux or blending with other coals can be considered [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Effects of Design/Operating Parameters and Physical Properties on Slag Thickness and Heat Transfer during Coal Gasification

Ryu

2015

Energies

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Abstract:The behaviors of the slag layers formed by the deposition of molten ash onto the wall are important for the operation of entrained coal gasifiers. In this study, the effects of design/operation parameters and slag properties on the slag behaviors were assessed in a commercial coal gasifier using numerical modeling. The parameters influenced the slag behaviors through mechanisms interrelated to the heat transfer, temperature, velocity, and viscosity of the slag layers. The velocity profile of the liquid slag was less sensitive to the variations in the parameters. Therefore, the change in the liquid slag thickness was typically smaller than that of the solid slag. The gas temperature was the most influential factor, because of its dominant effect on the radiative heat transfer to the slag layer. The solid slag thickness exponentially increased with higher gas temperatures. The influence of the ash deposition rate was diminished by the high-velocity region developed near the liquid slag surface. The slag viscosity significantly influenced the solid slag thickness through the corresponding changes in the critical temperature and the temperature gradient (heat flux). For the bottom cone of the gasifier, steeper angles were favorable in reducing the thickness of the slag layers.

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Section: Effects Of Slag Properties: Viscositymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Design/Operating Parameters and Physical Properties on Slag Thickness and Heat Transfer during Coal Gasification

Ryu

2015

Energies

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“…As a result, CO 2 in syngas increases and cold gas efficiency reduces as ash content in the coal increases [20]. In addition, the high ash coals have an inherently high possibility of slag plugging in gasifier and fouling in syngas cooler [38]. Furthermore, if additional flux is required, the flux and its cost are proportional to the ash contents.…”

Section: Ash Content and Coal Compositionmentioning

confidence: 99%

“…Due to economic constraints, the ash content of coal (% mass) for a slurry feeding gasifier is generally about 20% (considering the evaporation of water by heat) and about 40% for a dry feeding gasifier (Table 3) [20]. However, a reasonable amount of ash is required to coat the inner wall of a gasifier for insulating purposes and for protecting the membrane wall [38]. Table 3.…”

Section: Ash Content and Coal Compositionmentioning

confidence: 99%

“…Coals with the flow temperatures >1500 °C require additional flux. However, if the FT is below 1260 °C with high ash content, the possibility of fouling a downstream heat exchanger, such as the syngas cooler, by fly ash increases and more precaution should be practiced to prevent the fouling [38]. The effects of the chemical composition of ash on fusion temperatures were studied using regression analysis for 1250 ash samples of Eastern and Western coals [46,59].…”

Section: Ash Fusibility and Ash Flow Temperaturementioning

confidence: 99%

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Slag Behavior in Gasifiers. Part I: Influence of Coal Properties and Gasification Conditions

2013

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Abstract:In the entrained-flow gasifiers used in integrated gasification combined cycle (IGCC) plants, the majority of mineral matter transforms to liquid slag on the wall of the gasifier and flows out the bottom. However, a small fraction of the mineral matter is entrained (as fly ash) with the raw syngas out of the gasifier to downstream processing. This molten/sticky fly ash could cause fouling of the syngas cooler. To improve gasification availability through better design and operation of the gasification process, a better understanding of slag behavior and the characteristics of the slagging process is needed. Char/ash properties, gas compositions in the gasifier, the gasifier wall structure, fluid dynamics, and plant operating conditions (mainly temperature and oxygen/carbon ratio) all affect slagging behavior. Because coal has varying ash content and composition, different operating conditions are required to maintain the slag flow and limit problems downstream. In Part I, we review the main types and the operating conditions of entrained-flow gasifiers and coal properties used in IGCC plants; we identify and discuss the key coal ash properties and the operating conditions impacting slag behavior; finally, we summarize the coal quality criteria and the operating conditions in entrained-flow gasifiers. In Part II, we discuss the constitutive modeling related to the rheological studies of slag flow.

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Experimental study on gasification characteristics and slagging behavior of Chinese typical high ash fusion temperature coal in lab scale downflow gasifier

Zhang

Piao

et al. 2009

Asia-Pacific J Chem Eng

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In order to extend the applicability of entrained flow gasification technology by using Chinese high ash fusion temperature (AFT) coal with dry ash extraction, gasification characteristics and slagging behavior of Chinese high AFT coal were studied in a lab scale downflow gasifier. The results showed that under this experimental condition, the optimum temperature window which is suitable for dry ash extraction with high AFT coal ranges from 1573 to 1623 K, as well as the corresponding optimum O2/coal mass ratio ranges from 0.93 to 1.13. The cold gas efficiency and carbon conversion are around 42 and 90%, respectively in this experiment. The slag on the bottom of the gasifier and in the cyclone existed, on the whole, as solid except that some small parts were melted with several micrometers in diameter, while the slag in the bag filter had remained unmelted when continue operating at an optimum condition for 1.5 h. Due to the small percentage of melted parts in the slag, the tendency of plugging is small and the problems of plugging can be avoided at the exit of gasifier by gasifying Chinese high AFT coal at around 1623 K. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.

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Selection of IGCC candidate coals by pilot-scale gasifier operation

Cited by 46 publications

References 6 publications

Effects of Design/Operating Parameters and Physical Properties on Slag Thickness and Heat Transfer during Coal Gasification

Effects of Design/Operating Parameters and Physical Properties on Slag Thickness and Heat Transfer during Coal Gasification

Slag Behavior in Gasifiers. Part I: Influence of Coal Properties and Gasification Conditions

Experimental study on gasification characteristics and slagging behavior of Chinese typical high ash fusion temperature coal in lab scale downflow gasifier

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