氢氮气压缩机是生产合成氨的一项关键设备，其功能是气体输送或化学反应时提供动力。本文是以陕化集团老化肥厂区11#氢氮气压缩机的一次事故为例，分析了引发事故的原因和仪表联锁保护功能，研发设计了PLC逻辑关系，详细探讨了11#压缩机的联锁改进具体实施过程。结果证明：技术改造实现了保护设备的目的。

Hydrogen nitrogen compressor is a key equipment in the production of synthetic ammonia, providing power when gas or chemical reacts. This article bases on urea # 11 an accident of hydrogen nitrogen compressor in Shanhua Coal Chemical Group of old fertilizer factory, analyses the causes of accidents and the meter chain protection, researches and designs the PLC logic relationship, discusses the 11# compressor chain to improve the concrete implementation process of the compressor. Results show that: the technical renovation achieve the goal of the protection equipment.