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Title: Thermodynamic effects of calcium and iron oxides on crystal phase formation in synthetic gasifier slags containing from 0 to 27wt.% V2O3

Thermodynamic phase equilibria in synthetic slags (Al2O3–CaO–FeO–SiO2–V2O3) were investigated with 0–27 wt.% vanadium oxide corresponding to industrial coal–petroleum coke (petcoke) feedstock blends in a simulated gasifier environment. Samples encompassing coal–petcoke mixed slag compositions were equilibrated at 1500 °C in a 64 vol.% CO/36 vol.% CO2 atmosphere (Po2 ≈ 10–8 atm at 1500 °C) for 72 h, followed by rapid water quench, then analyzed by inductively coupled plasma optical emission spectrometry, X-ray diffractometry, and scanning electron microscopy with wavelength dispersive spectroscopy. With increasing CaO content, FeO content, or both; the slag homogeneity region expanded and a composition range exhibiting crystals was reduced. The mullite (Al6Si2O13) crystalline phase was not present in the slags above 9 wt.% FeO while the karelianite (V2O3) crystalline phase was always present in compositions studied if a sufficient amount of vanadium existed in the slag. Furthermore, based on the present experimental equilibrium evaluation, a set of isothermal phase diagrams showing effects of CaO and FeO on thermodynamic phase stabilities in the vanadium-bearing slags is proposed. Some uses of the diagrams for potential industrial practice are discussed.
Authors:
 [1] ; ORCiD logo [2] ;  [3] ;  [3] ;  [3] ;  [2]
  1. National Energy Technology Lab. (NETL), Albany, OR (United States); URS Corp., Albany, OR (United States)
  2. Canmet ENERGY, Ottawa, ON (Canada)
  3. National Energy Technology Lab. (NETL), Albany, OR (United States)
Publication Date:
OSTI Identifier:
1304160
Report Number(s):
A-CONTR-PUB-056
Journal ID: ISSN 0016-2361; PII: S0016236114010941
Grant/Contract Number:
FE0004000
Type:
Published Article
Journal Name:
Fuel
Additional Journal Information:
Journal Volume: 161; Journal Issue: C; Journal ID: ISSN 0016-2361
Publisher:
Elsevier
Research Org:
National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; phase diagram; equilibrium; coal; petroleum coke; additive agents