Analyzing organic sulfur in coal/char: Integrated mild degradation/XANES methods. Final technical report, September 1, 1993--November 30, 1994
- Southern Illinois Univ., Carbondale, IL (United States)
- Univ. of Kentucky, Lexington, KY (United States)
The overall goal of this study is to improve the understanding of sulfur in coals/chars via the use of combined advanced nondestructive and advanced destructive methods of sulfur analysis. This study combines selective oxidation, analytical pyrolysis, and sulfur X-ray Absorption Near Edge Structure Spectroscopy (XANES) analysis. Samples with a wide variety of sulfur contents, (0.63%--4.40%) have been prepared for use in this study. This includes steam gasification chars, oxidized coals and desulfurized coals as well of the original unaltered coals. Mild pyrolysis and XANES data shows that the sulfur chemistry of gasification chars is significantly different from that of the original coals. Mild pyrolysis of the samples that were oxidized with peroxyacetic acid showed that the level of simple thiophene structures observed in the pyrolysis products declines with increasing levels of oxidation. Sulfur XANES spectra of treated samples showed various effects depending on the treatment severity. The XANES spectra of less severely treated samples were similar, although not identical, to the untreated coal spectra. XANES of gasification chars indicated conversion of pyrite to pyrrhotite, removal of organic sulfide sulfur and dissolution of soluble inorganic sulfur species during gasification. Mild oxidation with peroxyacetic acid results in preferential oxidation of sulfide forms before thiophene forms but increasing oxidation severity leads to virtually all sulfur species being oxidized. Good agreement between W-band EPR and XANES data for aromatic sulfur contents were obtained. The TPR analysis of coal indicated that organic sulfur was present as alkyl-aryl sulfide, aryl-aryl sulfides, simple thiophenes and condensed thiophenes. TPR shows that non-thiophenic compounds are removed by PAA oxidation, and that the longer the oxidation is performed the greater is the removal of non-thiophenic sulfur structures.
- Research Organization:
- Illinois Dept. of Energy and Natural Resources, Springfield, IL (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FC22-92PC92521
- OSTI ID:
- 61093
- Report Number(s):
- DOE/PC/92521-T217; ON: DE95011396; TRN: AHC29516%%28
- Resource Relation:
- Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
Similar Records
Analyzing organic sulfur in coal/char: Integrated mild degradation/XANES methods. [Quarterly] technical report, December 1, 1993--February 28, 1994
Analyzing organic sulfur in coal/char: Integrated mild degradation/XANES methods. [Quarterly] technical report, September 1--November 30, 1993
Related Subjects
BITUMINOUS COAL
STRUCTURAL CHEMICAL ANALYSIS
CHARS
ORGANIC SULFUR COMPOUNDS
X-RAY SPECTROSCOPY
ABSORPTION SPECTROSCOPY
PROGRESS REPORT
COAL GASIFICATION
REDUCTION
TEMPERATURE CONTROL
SULFUR CONTENT
PHASE TRANSFORMATIONS
ELECTRON SPIN RESONANCE
OXIDIZERS
SAMPLE PREPARATION
CHEMICAL COMPOSITION
EXPERIMENTAL DATA