PTA装置低压液氮管线损坏原因

Damage causes of Low-pressure liquid nitrogen pipelines in PTA plants

PTA装置开停车或正常生产时均需要氮气作为保护气体,介绍了液氮系统的组成、工艺参数。叙述了液氮管线事故发生的经过。对其原因进行分析,认为是由于液氮瞬间流量太大,来不及汽化升温,造成管线内液击同时氮气管线瞬间达到-40℃,材料脆性爆破压力降低,此时液氮管线发生液击,液击压力大于管线爆破压力,管线发生短裂。提出了对液氮系统进行改进,改进连锁系统和气化系统,取得较好的效果。

The article introduces the composition and process parameters of a liquid nitrogen system.The accident of liquid nitrogen pipeline is described.Analyze its cause.It is thought that the instantaneous flow of liquid nitrogen is too large to evaporate and heat up,which causes the nitrogen pipeline to reach-40℃instantly,resulting in brittle fracture of the material.The improvement of the liquid nitrogen system is proposed.Improve the interlocking system and gasification system and achieve better results.