Viscosity measurements and empirical predictions for some model gasifier slags—II

Hurst, H.J.; Patterson, Joshua T.; Quintanar, A

doi:10.1016/s0016-2361(00)00043-0

Cited by 35 publications

(23 citation statements)

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“…The lack of reliable experimental data, as well as a large scatter between available results in this system, does not allow the model predictions to be fully confirmed. Figure 13 presents experimental [52,53,73] viscosities and calculated isocombs in the Al 2 O 3 -CaO-'FeO'-SiO 2 system in equilibrium with metallic iron at 1773 K and 10 wt pct of 'FeO.' The trends of the isoviscosity curves are very similar to those of the modified Urbain model developed by the authors, [31] except in the low silica area.…”

Section: B Prediction Of Viscositiessupporting

confidence: 56%

“…The priority has been given to the most recent studies. [47,48,49] The present set of model parameters does Good agreement between model predictions and experimental [28,29,37,46,[51][52][53]55] viscosities in the Al 2 O 3 -CaO-SiO 2 system at 1773 K is demonstrated in Figure 10. The results of Saito and Kawai [37] differ significantly from the others and have been rejected.…”

Section: B Prediction Of Viscositiesmentioning

confidence: 51%

“…In summary, the optimization was based on the following experimental data for Al 2 O 3 , [33,[41][42] 'FeO', [3] SiO 2 , [28,43,44] Al 2 O 3 -SiO 2 , [28,29,33] CaO-SiO 2 , [28,29,32,45,46] 'FeO'-SiO 2 , [28,[47][48][49] Al 2 O 3 -CaO, [46,50] Al 2 O 3 -CaO-SiO 2 , [28,29,46,[51][52][53][54][55][56][57] CaO-'FeO'-SiO 2 , [48,58,59] Al 2 O 3 -'FeO'-SiO 2 , [60] Al 2 O 3 -CaO-'FeO', [38] Al 2 O 3 -CaO-'FeO'-SiO 2 . [52,53,58,61] About 3700 experimental points were selected in total.…”

Section: Experimental Datamentioning

confidence: 99%

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A quasi-chemical viscosity model for fully liquid slags in the Al2O3-CaO-‘FeO’-SiO2 system

Kondratiev

Jak

2005

Metall Mater Trans B

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A structurally based viscosity model for fully liquid silicate slags has been proposed and applied to the Al 2 O 3 -CaO-'FeO'-SiO 2 system at metallic iron saturation. The model links the slag viscosity to the internal structure of melts through the concentrations of various anion/cation structural units (SUs). The concentrations of structural units are equivalent to the second nearest neighbor bond concentrations calculated by the quasi-chemical thermodynamic model. This viscosity model describes experimental data over the entire temperature and composition range within the Al 2 O 3 -CaO-'FeO'-SiO 2 system at metallic iron saturation and can be extended to other industrial slag systems.

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Section: B Prediction Of Viscositiessupporting

confidence: 56%

Section: B Prediction Of Viscositiesmentioning

confidence: 51%

Section: Experimental Datamentioning

confidence: 99%

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A quasi-chemical viscosity model for fully liquid slags in the Al2O3-CaO-‘FeO’-SiO2 system

Kondratiev

Jak

2005

Metall Mater Trans B

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“…Hurst et al performed a series of rotary viscometry measurements on Australian bituminous coal ash slags to determine their critical viscosity temperatures and viscosities as a function of composition [108][109][110]. They recorded the shear rate and torque as a function of temperature, at 30°C intervals during stepwise cooling.…”

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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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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“…To calculate viscosity, they suggested the following equation, based on a least squares fit of the experimental data, for the temperature range of 1,400-1,500 °C: This study was specifically aimed at the SiO 2 -Al 2 O 3 -CaO-FeO (SACF) system at 5 and 10% wt FeO. Later, Hurst et al [80] where A and E are parameters to be fitted from the experimental data, and 0  is the hypothetical viscosity of the non-networking slag expressed as a complicated exponential function, which depends on many parameters such as the molar volume at the melting temperature, the gas constant, the mole fraction, etc. The modified 'basicity' index * Bi was calculated from another complicated function that depends on many parameters, especially on the mass percentage of the various components present in the slag, for example, CaO-SiO 2 -Al 2 O 3 -MgO, etc.…”

Section: A Brief Review Of Various Viscosity Modelsmentioning

confidence: 99%

Slag Behavior in Gasifiers. Part II: Constitutive Modeling of Slag

Massoudi

Wang

2013

Energies

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Abstract:The viscosity of slag and the thermal conductivity of ash deposits are among two of the most important constitutive parameters that need to be studied. The accurate formulation or representations of the (transport) properties of coal present a special challenge of modeling efforts in computational fluid dynamics applications. Studies have indicated that slag viscosity must be within a certain range of temperatures for tapping and the membrane wall to be accessible, for example, between 1,300 °C and 1,500 °C, the viscosity is approximately 25 Pa·s. As the operating temperature decreases, the slag cools and solid crystals begin to form. Since slag behaves as a non-linear fluid, we discuss the constitutive modeling of slag and the important parameters that must be studied. We propose a new constitutive model, where the stress tensor not only has a yield stress part, but it also has a viscous part with a shear rate dependency of the viscosity, along with temperature and concentration dependency, while allowing for the possibility of the normal stress effects. In Part I, we reviewed, identify and discuss the key coal ash properties and the operating conditions impacting slag behavior.

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Viscosity measurements and empirical predictions for some model gasifier slags—II

Cited by 35 publications

References 1 publication

A quasi-chemical viscosity model for fully liquid slags in the Al2O3-CaO-‘FeO’-SiO2 system

A quasi-chemical viscosity model for fully liquid slags in the Al2O3-CaO-‘FeO’-SiO2 system

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

Slag Behavior in Gasifiers. Part II: Constitutive Modeling of Slag

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