Two-stage pyrolysis of heavy oils. 3. Pyrolysis of tar-sand bitumens. Relation between ethylene yield and structural characteristics of heavy oils
✍ Scribed by Maki Itoh; Toshimitsu Suzuki; Yoshihiko Tsujimoto; Ken-ichi Yoshii; Yoshinobu Takegami; Yoshihisa Watanabe
- Publisher
- Elsevier Science
- Year
- 1983
- Tongue
- English
- Weight
- 527 KB
- Volume
- 62
- Category
- Article
- ISSN
- 0016-2361
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✦ Synopsis
Thermal cracking of tar-sand bitumens has been carried out using a two-stage pyrolysis reactor with temperature zones of 440°C and 750-600'%, respectively. Feedstocks were pyrolysed in the first stage into cracked oils, which were carried to the second stage for subsequent pyrolysis. Only 12-l 4 wt% of ethylene was obtained from tar-sand bitumens at the residence time of 1.2 s in the second stage, although 27 and 16 wt% were obtained from Taching and Iranian heavy vacuum residues, respectively. The tar-sand bitumens contain shorter paraffinic straight-chains and have more branched molecules than the vacuum residues of petroleum. A straight-chain paraffin index is proposed, with which a good correlation was obtained between ethylene yield and the fraction of straight-chain paraffin carbons in the heavy oil.