文献类型：期刊文献

英文题名：Analysis of failed ethylene cracking tubes

作者：Guan, Kaishu[1]; Xu, Hong[1]; Wang, Zhiwen[1]

机构：[1]E China Univ Sci & Technol, Res Inst Proc Equipment, Shanghai 200237, Peoples R China

年份：2005

卷号：12

期号：3

起止页码：420

外文期刊名：ENGINEERING FAILURE ANALYSIS

收录：;EI(收录号：2005098860445);WOS:【SCI-EXPANDED(收录号:WOS:000227423000009)】；

语种：英文

外文关键词：bulging failure; cracks; overheating; tube failures; chemical-plan failures

摘要：The failure of ethylene cracking tubes at an elevation of about 5 in in radiant chambers after one-year service has been analysed. Bulges and circumferential cracks, oriented towards the walls/burners, are the result. The investigation included tensile tests, optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analysis. Analysis revealed that ruptures found in the tubes were caused by overheating of the tubes because of inappropriate burning of bottom burners. Significant growth of precipitates of carbide was observed in the failed zones which results in the drastic reduction of material ductility. The bulged zones also showed a globular form of grains. Tube bowing, due to the restricted growth during the hot expansion, promotes cracks. To avoid such overheating, precautions should be taken while improving the burning condition of the bottom burners and decreasing the peak tube metal temperature. It is necessary to check the tube temperature periodically in critical positions and one should ensure that the temperature is less than the design temperature. (C) 2004 Elsevier Ltd. All rights reserved.