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Title: Microwave-assisted pyrolysis of Mississippi coal: A comparative study with conventional pyrolysis

Pyrolysis conditions greatly affect the structure-reactivity relationship of char during coal gasification. Here, this work investigated the effect of temperature and microwave heating on the structural properties of the chars generated during pyrolysis, as well as gaseous and tar products. Results showed that microwave pyrolysis of Mississippi coal produced more gaseous products and less tars compared to conventional pyrolysis. Higher CO/CO 2 ratio (>1) was observed under microwave pyrolysis compared to conventional pyrolysis (CO/CO2 < 1), which may be explained by a greater extent of gasification between solid carbon and the CO 2 formed during microwave pyrolysis. Additionally, in microwave pyrolysis, the oil tars generated exhibited lower concentrations of polar oxygenates, while the wax tars showed higher concentrations of non-polar alkanes, as observed from the intensity of CH vibrations in FTIR. The product compositions and FTIR analysis of the tars (oils and waxes) suggest that the microwave interacted preferentially with these polar species, which have relatively higher dielectric properties compared to alkanes. The structure–reactivity relationship of the chars produced was also investigated using a variety of characterization tools such as XRD, BET, SEM, EDS, and FTIR. Finally, the char reactivity towards combustion suggested that microwave-produced chars have a higher thermalmore » stability, likely due to lower O/C ratios, and could be utilized in the metallurgical industry.« less
ORCiD logo [1] ;  [2] ;  [2] ;  [2] ;  [3]
  1. National Energy Technology Lab. (NETL), Morgantown, WV (United States); AECOM, Morgantown, WV (United States)
  2. National Energy Technology Lab. (NETL), Morgantown, WV (United States)
  3. National Energy Technology Lab. (NETL), Morgantown, WV (United States); Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry
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Grant/Contract Number:
Accepted Manuscript
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Additional Journal Information:
Journal Volume: 217; Journal Issue: C; Journal ID: ISSN 0016-2361
Research Org:
National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States)
Sponsoring Org:
USDOE Office of Fossil Energy (FE)
Country of Publication:
United States
01 COAL, LIGNITE, AND PEAT; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Microwave pyrolysis; Lignite coal; Tar yield; Char properties; Low rank coal; Combustion reactivity
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