Abstract: Aiming at the issues encountered during the operation of the SL-Ⅱ ethylene cracking furnace (F-02102) of a petrochemical company, including aging of radiant section tube, short operation cycles, low feed load and inferior thermal efficiency, the CBL (China Northern Furnace) gas cracking technology was adopted to carry out the retrofit. The core of the retrofit was to replace the radiant section furnace tubes with 2-1-1-1 type four-pass configuration, optimize and adjust the convection section tube bundles, and support the upgrade of relevant auxiliary systems. After the retrofit, the cracking furnace can flexibly process a variety of feedstocks including ethane-rich gas, liquefied petroleum gas (LPG) and light naphtha. Its operation cycle is greatly extended from less than 70 days to 90~100 days, the feed load is increased to 110% of the original design capacity, the flue gas outlet temperature drops remarkably, and the thermal efficiency rises above 94%. All technical and economic indicators meet or exceed the retrofit targets, bringing favorable economic benefits to the enterprise.

Key words: SL-Ⅱ ethylene cracking furnace, CBL technology, radiant section furnace tubes, convection section tube bundles