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

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.
Authors:
ORCiD logo [1] ;  [1] ;  [1]
  1. National Energy Technology Lab. (NETL), Albany, OR (United States). Structural Materials Development Division
Publication Date:
Report Number(s):
NETL-PUB-20045
Journal ID: ISSN 0378-3820; PII: S0378382015301727
Type:
Accepted Manuscript
Journal Name:
Fuel Processing Technology
Additional Journal Information:
Journal Volume: 142; Journal Issue: C; Journal ID: ISSN 0378-3820
Publisher:
Elsevier
Research Org:
National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States). In-house Research
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; coal gasification; critical viscosity temperature; ash fusion; rotary viscometry; non-Newtonian flow; slag
OSTI Identifier:
1240881