尿素合成塔物料管管口裂纹统计与成因初探

对水溶液全循环法尿素合成塔物料管检验缺陷进行了统计分析，指出物料管缺陷主要是液氨物料管管口裂纹，其是由物料管焊接结构、温差应力、腐蚀介质和工况条件等因素综合影响造成的。并指出可以通过控制工艺稳定性，采取预混甲液和液氨以及改善焊接接头应力集中程度等方法来降低液氨进口管管口裂纹出现的频率。

Statistics of Cracks Occurred at End of Medium Pipe in Urine Synthetic Tower and Cause Analysis

In this article, the statistical analysis for the defects inspected in the fluid pipe in urea synthesis tower with water solvent and whole cycle process was carried out. It was indicated that the defects in fluid pipe is the crack occurred at the end of pipe contai-ning liquid ammonia, which is caused by the comprehensive factors from welding structure, thermal stress, corrosive fluid and the other working condition. It was also indicated that through the control of process stability, the use of mixing methylamine and ammonia liq- nids and the improvement of the stress concentration in welding joint, the occurrence of the crack appeared at the liquid ammonia inlet can be reduced.