- Title
- Impact of coal pyrolysis products as a rheological additive on thermoplasticity of a coking coal
- Creator
- Xie, Wei; Stanger, Rohan; Tran, Quang Anh; Smith, Nathan; Wall, Terry; Lucas, John
- Relation
- Energy and Fuels Vol. 32, Issue 4, p. 4382-4390
- Publisher Link
- http://dx.doi.org/10.1021/acs.energyfuels.7b03232
- Publisher
- American Chemical Society (ACS)
- Resource Type
- journal article
- Date
- 2018
- Description
- Thermoplasticity is a determining factor for the development of the coke structure and coke strength. Mobile phase, whether vaporizable or not, may significantly affect thermoplasticity during coal coking. This work studies the effect of the mobile phase, including the volatile tar and extractable metaplast generated from one bituminous coking coal, on the thermo-swelling of the raw coal. The volatile tar was collected when the raw coal was heated from room temperature to 450 °C at a heating rate of 5 °C/min, while the metaplast was extracted from the heated char. Molecular properties of the tar and metaplast were characterized using a laser desorption/ionization-time of flight-mass spectrometry technique (LDI-TOF-MS). Thermo-swelling of the raw coal and its blends with the volatile tar and extractable metaplast was investigated using a computer-aided thermal analysis (CATA). The volatile (C and H) evolution rate of the heating coal samples was tracked using a dynamic elemental thermal analysis (DETA), and the weight loss rate was investigated using thermogravimetric analysis (TGA). It was found that the extracted metaplast has a higher molecular weight distribution than that of the volatile tar. The swelling and thermal changes of the heating coal increased with the addition of tar or metaplast. The weight loss rate prior to coal swelling increased with the additives, while the raw coal showed a higher volatile release after maximum swelling than the blends. The addition of metaplast into the raw coal led to greater swelling, increased exothermicity, and resulted in a higher thermal conductivity than the addition of volatile tar during the primary devolatilization, particularly when the additive was 20 wt % in the blend. Different influences of thermoplasticity of the blends indicated that the interactions between the additive and the coal are affected by the molecular weight distribution of the additive. These findings will aid in the selection of the additive for improving thermoplasticity of low-caking coals to benefit coke production.
- Subject
- thermoplasticity; coal; coke structure; coke strength
- Identifier
- http://hdl.handle.net/1959.13/1385675
- Identifier
- uon:32272
- Identifier
- ISSN:0887-0624
- Language
- eng
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