Simulation Of The Temperature Distribution In A Hydrogen-Making Furnace And Thermal Stress Analysis Of The Reformer Tubes

Hydrogen-making furnace is the key equipment in the natural gas and steam reformer plant. The temperature field in the radiation section has a significant effect on reformer tube life and hydrogen production rate. In this thesis, temperature field in the radiation section and temperature distribution at the outer wall of the reformer tube were simulated by using CFD software FLUENT. Then thermal-structure coupling analysis was performed to evaluate the stress distribution and the deformation at the reformer tube by using FEA software ANSYS. Finally, the strength of the spring hanger was investigated. The main conclusions are as follows:1. Flow field in the radiation section is affected largely by high-speed jet of burners nozzle. High-speed jet induces backflow, which produces bias flow toward the middle and causes high-speed jet far away from flue outlet dissipate very quickly. Flow field in the bottom area of the radiation section was uniform.2. Temperature field in the radiation section is nonuniform. Temperature was high below burners, temperature was low and temperature distribution became uniform at the bottom of radiation section. The flame far away from the flue outlet is longer than that near the flue outlet, and is deflected toward the middle. Temperature gradient is large around the reformer tube.3. Heat flux distribution of outer wall along the height of reformer tube is nonuniform, with an increase first and then decrease manner. The maximum heat flux is located at1/3total height of furnace chamber from furnace top. The heat flux of reformer tube in the middle is greater than that on both sides.4. Temperature distribution of outer wall along the height of reformer tube is also nonuniform, which increased first and then decreased. The maximum temperature is located at1/3total height of furnace chamber from furnace top. The temperature of reformer tube on both sides is remarkably smaller than that in the middle and t emperature gradient of reformer tube on both sides is great.5. The maximum thermal stress is found in the location where the temperature difference is largest. The thermal stress is much larger than the stress induced by pressure, but can be greatly reduced if using S-bend tail tube. The strength of reformer tube and tail tube can meet the requirements of the pressure vessel standard based on design by analysis.