Failure analysis of a reactor effluent air cooler
Failure analysis of a reactor effluent air cooler
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反应堆流出空气冷却器故障分析
DOI：
10.1016/j.engfailanal.2013.02.025
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发表时间：
2013-07-01
影响因子：
4
通讯作者：
Jin, Haozhe
中科院分区：
文献类型：
--
作者：
Ou, Guofu;Wang, Kuanxin;Jin, Haozhe
针对某炼油厂加氢裂化反应器流出物空气冷却器爆管的原因进行了研究。为此，首先采用解剖分析法，发现铵盐晶体，根据实际操作条件，利用白杨软件建立离子平衡模型，计算NH 4Cl和NH 4 HS的结晶温度。结果表明，随着原料中氯、氮含量的不同，NH 4Cl的结晶温度在175 ~ 210 ℃之间，高于REAC的操作温度。为分析冷风机结构对铵盐沉积位置的影响，采用Fluent软件对冷风机联箱和管束进行了数值模拟。结果表明，由于在集箱进口两侧形成较大的旋涡，使集箱进口存在偏流区。集箱入口两侧管内多相流流速和水相含量较低，导致NH 4Cl沉积和沉积物下腐蚀。为了验证失效分析结果，利用红外摄像机对其他在役空冷器进行了检测，结果表明，其他空冷器在相同位置也存在堵塞现象。最后提出了减少NH 4Cl沉积的建议。(C)2013爱思唯尔有限公司保留所有权利。
In the present research, root causes of the tube explosion of a refinery hydrocracking reactor effluent air cooler (REAC) were studied. For this purpose, anatomical analysis was firstly used and ammonium salt crystals were found. Based on the actual operating conditions, ionic equilibrium model was established by Aspen software to calculate the crystal temperature of the NH4Cl and NH4HS. The results indicate that NH4Cl crystal temperature ranged from 175 degrees C to 210 degrees C with different chlorine and nitrogen content of the feedstock, which is higher than the operating temperature of REAC. To analyze the impact of the air cooler structure on the ammonium salt deposition location, numerical simulation including the air cooler header box and bundles was conducted by the Fluent software. The results show that a bias flow regime exists because of the large vortex formed in both sides of the header box inlet. The velocity and aqueous phase fraction of the multiphase were low in the tubes of the header box inlet both sides, which result in the NH4Cl deposition and under-deposit corrosion. In order to verify the failure analysis results, other in service air coolers were inspected using the infrared camera, and the results show that other air coolers had the plugging features at the same position. Finally, some recommendations were given to mitigate the NH4Cl deposition. (C) 2013 Elsevier Ltd. All rights reserved.