| CPC F28F 1/40 (2013.01) [C10G 9/20 (2013.01)] | 10 Claims |

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1. A thermal cracking tube having one or more fluid agitating elements formed on and projecting inwardly from an inner surface of the tube,
the one or more fluid agitating elements comprising
a fin extending along the inner surface of the tube, and
bumps provided on a region near the fin and projecting inwardly from the inner surface of the tube, wherein
the fin comprises a plurality of fins formed on the inner surface of the tube at an interval of I, and
the bumps are provided on the region at least up to I/2 of the upstream side and/or I/2 of the downstream side of the fin.
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