Changes in pyrolysis tar yield with increasing sweep gas superficial velocity were measured in a fixed bed reactor operated at 10 K min-' at temperatures up to 500Β°C. Tar yields were observed to increase with gas velocity by about 5 wt% when the superficial velocity was changed over the range 0.15-2
Correlation of tar yields from rapid pyrolysis with coal type and pressure
β Scribed by Glen H. Ko; William A. Peters; Jack B. Howard
- Publisher
- Elsevier Science
- Year
- 1987
- Tongue
- English
- Weight
- 545 KB
- Volume
- 66
- Category
- Article
- ISSN
- 0016-2361
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β¦ Synopsis
A new correlation independently relating maximum tar yield from rapid pyrolysis (heating rate 2 100 K s-') to coal type and to total pressure is presented. Coal type effects are treated using only information on the elemental composition of the unpyrolysed coal. Pressure effects are correlated via empirical parameters obtained from best-tit analyses of existing data. The correlation is tested against experimental data for coals from the USA, France and W. Germany representing a wide range of rank, and for pressures from 'vacuum' to 9 MPa. Satisfying results are obtained, with predictions of tar yield generally within f 5 wt % (of dmmf coal) of observed values at all pressures for most coals. The correlation is most suited to predicting maximum tar yields under reaction conditions affording minimal opportunity for extra-particle secondary reactions of newly formed pyrolysis tars. It is also useful for predicting probable upper bounds on pyrolysis tar yields under other operating conditions.
π SIMILAR VOLUMES
The pyrolysis of coal tar and petroleum pitches was studied under nitrogen pressures from 2 to 150 bar at temperatures between 300 and 600Β°C. The resulting residues were investigated by TGA, polarized-light microscopy and X-ray diffraction. It is shown that increasing pressure does not only increase