内加热式氨分解反应器流动及传热研究

Study on Flow and Heat Transfer in an Internally Heated Ammonia Decomposition Reactor

中文关键词: 氨分解反应器；翅片；多孔介质  传热

英文关键词: Ammonia decomposition reactor  Fins  Porous medium  Heat transfer

中文摘要:

      以内加热式氨分解反应器为研究对象，旨在强化内部传热并提高氨分解率。通过实验测定一种氨分解催化剂的催化特性，并基于Ansys Fluent中的多孔介质模型对三种结构的反应器进行流动与传热模拟，分析反应过程。研究了加热温度、预热温度对反应进程的影响，探讨了翅片类型、翅片高度及反应管长度对反应器性能的影响规律。结果表明：HTZ204N镍基催化剂的使用温度需不低于750℃；提高进口NH?的预热温度有助于提升催化剂利用率与氨分解率；模型c采用的螺旋型翅片在增强内部扰动、提高氨分解率方面更具优势；高度为16 mm的翅片可有效强化传热并维持较低压降；当NH3处理量5000 L/h、加热温度达800℃且反应管长度为135–210 mm时，氨分解率均可超过90%，设备运行高效且催化剂利用率高。

英文摘要:

      This study focuses on an internally heated ammonia decomposition reactor, aiming to enhance internal heat transfer and improve the ammonia conversion rate. The catalytic characteristics of an ammonia decomposition catalyst were determined experimentally. Numerical simulations of flow and heat transfer in three reactor structures were performed using the porous medium model in Ansys Fluent, and the reaction process was analyzed. The effects of heating temperature and preheating temperature on the reaction progress were investigated. The influences of fin type, fin height, and reaction tube length on reactor performance were also explored. The results indicate that the operating temperature for the HTZ204N nickel-based catalyst should not be lower than 750 °C. Increasing the preheating temperature of the inlet NH? enhances catalyst utilization and the ammonia conversion rate. Model c, employing spiral fins, demonstrates superior performance in enhancing internal flow disturbance and increasing the ammonia conversion rate. Fins with a height of 16 mm effectively intensify heat transfer while maintaining a relatively low pressure drop. When the NH? throughput is 5000 L/h, the heating temperature reaches 800 °C, and the reaction tube length ranges from 135 to 210 mm, the ammonia conversion rate exceeds 90%, ensuring efficient reactor operation and high catalyst utilization.