焦炭塔顶颈部筒体减薄及油气出口接管焊缝开裂原因分析

广州分公司延迟焦化装置焦炭塔运行8年后发现塔顶颈部与油气出口接管连接处焊缝产生了裂纹,分析其原因:(1)接管处是几何不连续区域,应力水平偏高;(2)焦炭塔的操作是循环往复式的,构成了疲劳载荷,进而产生了循环应力应变;(3)介质中的H2S和HCl对塔壁造成腐蚀。针对产生的原因,采取了在焦炭塔上部及塔顶颈部衬一层0Cr13Al和更换塔顶筒体和油气出口接管等措施,为焦化装置的长周期运行奠定了基础。

Thinning out the Shank Shell on the Top of Coke Drum and Cause Analysis on Weld Seam Failure of Connection Tube at Oil and Gas Outlet

After the coke drum running for 8 years in Guangzhou Branch, weld seam failure occurs on the weld joint between the top neck of coke drum and the connection tube of oil and gas outlet, through analysis, the following reasons are found:(i) there is a discontinuous geometry zone at the pipe connection, the stress level is higher there; (ii) the coke drum is operating at the mode of recycle and reciprocating that forms fatigue loading which creates repeated stress strain;(iii) H2S and HC1 in the medium erodes the drum wall. To solve this problem, 0Crl3Al was lined on the neck and upper part of the coke drum, the top drum wall and pipe connection at oil and gas outlet was replaced, which lays a foundation for long-term operation of the coke drum.