Abstract <p>Approximate 36% of the total heat is produced by coke oven gas (COG) in the coke oven and has a great potential for recovery. In order to recover the surplus heat effectively, a water-jacketed coke oven heat exchanger is installed at the coke oven ascension pipe. However, this core unit suffers from uneven water vapor distribution on the jacket side, which leads to decreased heat transfer efficiency and localized high temperature bulging. In this study, Fluent was used to simulate a single jacketed heat exchanger to investigate the effect of fin position (water jacket side or COG side) and its number (4, 8, 12) on the heat transfer characteristics of the ascension pipe when the flow rate of cooling water on the water jacket side is 0.3 m/s at a coking time of 16 h. The results indicate that, considering the flow field, performance evaluation metrics, and practical engineering issues, it is more advantageous to install the fins on the water jacket side. Furthermore, as the number of fins on the water jacket side increases, the outlet temperature on the COG side decreases, leading to enhanced heat transfer efficiency. The heat transfer effect was optimal when the number of fins of jacketed ascension pipe heat exchanger was augmented to a total of 12.</p>