Prediction of temperature of critical viscosity for coal ash slag

Song, Wenjia; Yan-he, Dong; Wu, Yuping; Zhu, Zhaojie

doi:10.1002/aic.12500

Cited by 33 publications

(17 citation statements)

References 17 publications

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“…The availability of CALPHAD-based software tools today means the liquidus temperature of a slag can be calculated readily from its composition, as well as its subliquidus solid fraction as a function of temperature. Song et al have developed a model that relate the critical transition temperature to the liquidus temperature, as calculated from the coal ash slag composition [113]. The approach offers greater flexibility in the range of coal ash compositions over which the model is applicable, compared with earlier approaches based on proxy variables.…”

Section: Thermophysical Modeling Of Coal Ash Slagsmentioning

confidence: 99%

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Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes

Hsieh

Kwong

Bennett

2016

Fuel Processing Technology

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Coal gasification yields synthesis gas, an important intermediate in chemical manufacturing. It is also vital to the production of liquid fuels through the Fischer-Tropsch process and electricity in Integrated Gasification Combined Cycle power generation. Minerals naturally present in coal become molten in entrained-flow slagging gasifiers. Molten coal ash slag penetrates and dissolves refractory bricks, leading to costly plant shutdowns. The extent of coal ash slag penetration and refractory brick dissolution depends on the slag viscosity, the gasification temperature, and the composition of slag and bricks. We measured the viscosity of several synthetic coal ash slags with a high-temperature rotary viscometer and their ash fusion temperatures through optical image analysis. All measurements were made in a carbon monoxide-carbon dioxide reducing atmosphere that approximates coal gasification conditions. Empirical correlation models based on ash fusion temperatures were used to calculate critical viscosity temperatures based on the coal ash compositions. These values were then compared with those obtained from thermodynamic phase-transition models. An understanding of slag viscosity as a function of ash composition is important to reducing refractory wear in slagging coal gasifiers, which would help to reduce the cost and environmental impact of coal for chemical and electricity production.Published by Elsevier B.V.

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Section: Thermophysical Modeling Of Coal Ash Slagsmentioning

confidence: 99%

“…Huainan [111], Shen-Fu [112]) under gasification conditions. Both constant rotation rate (20 rpm) [111] and variable rotation rate (10 to 100 rpm) methods were employed [112,113]. Slag samples were quenched periodically and removed for study using SEM analysis.…”

Section: High-temperature Rotary Viscometrymentioning

confidence: 99%

Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes

Hsieh

Kwong

Bennett

2016

Fuel Processing Technology

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“…The T cv predicted in this method can only be used as reference. Song et al [66] derived an empirical equation to correlate T cv of 40 synthetic ash samples with liquidus temperature (i.e., the temperature at which solids begin to precipitate as liquid slag is cooling) and accurately predicted T cv of eight Chinese coal ash samples. The liquidus temperature is calculated by FactSage using a synthetic slag SiO 2 -Al 2 O 3 -CaO-Fe 2 O 3 -MgO system.…”

Section: Temperature Of Critical Viscositymentioning

confidence: 99%

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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“…... (1) This study adopted the similar method 10) to find out a correlation between the measured deformation temperature (T deform. ) and liquidus temperature (T liquidus ) of semi-synthetic slag samples (Fig.…”

Section: Formulation Of Equationsmentioning

confidence: 99%

Development of Slag Flowability Prediction Formula for Blast Furnace Operation and Its Application

Shiau

Liu

2018

ISIJ Int.

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In this study, the effects of MgO content, Al 2 O 3 content, TiO 2 content and C/S ( = CaO/SiO 2 ) on slag flowability are investigated for blast furnace (BF) operation. The liquidus temperature and the viscosity of semisynthetic slags are measured using an optical softening temperature detector and a viscometer, respectively. Based on the measured data, equations of the liquidus temperature and the viscosity for the semi-synthetic slags (SiO 2 -Al 2 O 3 -CaO-MgO-TiO 2 ) were formulated via the multiple-regression method. In operation practice of BF, the slag flowability is mainly determined by both viscosity and liquidus temperature. A combined slag flowability index, including viscosity and liquidus temperature, has been designed in this research to indicate appropriate slag flowability. This index has been incorporated into the tapping system of CSC (China Steel Corporation) BF. Based on the calculated liquidus temperature and viscosity of the final slag inside BF, the system is able to predict the difficulty of slag flow for the coming tapping. It can immediately provide BF staffs some information to control the variation of slag flowability via the effective operation practice such as enforcing management of thermal state or adjusting the chemical composition of final slag via the burden of BF.

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Prediction of temperature of critical viscosity for coal ash slag

Cited by 33 publications

References 17 publications

Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes

Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes

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

Development of Slag Flowability Prediction Formula for Blast Furnace Operation and Its Application

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