摘要：
The construction,characteristics and operation conditions of the four-in-one fired furnace for the continuous catalytic reforming unit are introduced,and the causes of leakage of outlet manifold blind flange are analyzed.It is concluded that inner ring and the winding belt are subject to the impingement erosion of vortex,which leads to the failures of inner ring and seal.Whereas,the addition of heat insulation has accelerated the failure of seal.The gasket has been operating for a long time with no maintenance.To solve the leaking problem,the gasket has been replaced,the heat insulation is removed,the risks are evaluated and important locations are supervised.It is also recommended to upgrade gasket structure for manifold blind flange and apply flexible graphite corrugated metal gaskets which can resist to the vortex impingement erosion.The flange type and blind head structure are improved and vortex prevention facilities are added.The risks evaluation is performed for the seals in high-temperature,high-pressure,inflammable and explosive services.Maintenance should be made in a timely manner to prevent accidents.%介绍某石化公司连续重整装置四合一加热炉的结构、特点以及运行状况,并对加热炉出口集合管盲盖法兰泄漏故障进行了分析.分析认为集合管内存在旋流,长时间对缠绕垫片内环和缠绕带进行冲刷,致使内环和密封失效;盲盖增设保温,加速了密封失效过程,且垫片运行周期较长,存在失修情况.针对此次故障采取更换垫片、拆除保温、进行风险评估、重点监护等措施.另外建议升级集合管盲盖密封结构,采用波齿复合垫或齿形复合垫,可以一定程度上抵抗这种涡旋冲刷;改进法兰形式,对盲盖结构进行改进,增加防旋流设施,对类似特殊工况的高温、高压、易燃、易爆部位的密封进行风险评估,有针对性地进行检修,避免失修.
