Abstract: To address the issues of discontinuous temperature distribution and insufficient separation efficiency in existing steam cracking test evaluation units, a single-tube electrically heated steam cracking test evaluation unit was designed and developed by referencing the heating mode and process parameters of industrial tubular steam cracking furnaces used for ethylene production. Subsequently, the performance of the developed unit was evaluated using straight-run naphtha as the feedstock. The results indicate that the unit employs electrically heated graphite tube resistance heating, effectively resolving the issue of discontinuous temperature distribution within the cracking furnace tube; no temperature plateaus were observed during the test process. Furthermore, the unit achieves a coordinated balance among the feed system, preheating system, and product cooling-recovery-separation system, ensuring adequate separation of gaseous and liquid products. The optimized steam cracking conditions for straight-run naphtha were determined to be: a feed pressure of 0.1 MPa, a cracking temperature of 890 ℃,a steam-to-oil mass ratio of 0.6, a reaction time of 100 ms, and a cracking depth not exceeding 0.50, which align with the optimal operating conditions of industrial steam cracking units. Consequently, the experimental results obtained from this steam cracking test evaluation unit provide reliable data support for raw material formulation and process optimization in industrial cracking units.

Key words: ethylene, steam pyrolysis, evaluation test, test equipment, cracking furnace