尿素设备腐蚀的影响因素分析及防腐措施

针对尿素生产的特点,分析了对尿素设备腐蚀的影响因素:介质温度、氨碳摩尔比、水碳摩尔比、氨基甲酸铵溶液浓度、氧含量、硫含量、氯离子含量和介质流速等。提出了正常生产和停车封塔2种情况下的防腐措施。正常生产期间要严格控制如下指标:操作温度、系统的加氧量、硫含量、氯离子含量、氨碳比和水碳比;停车期间要严格控制系统的氨碳比和水碳比,同时根据不同状况来确定停车封塔时间。

Analysis on equipment corrosion and its measures against it in Urea plant

According to the characters of Urea production,the influence factors on the equipment corrosion in Urea plants are analyzed,which includes medium temperature,the Mol ratio of ammonia to carbon dioxide,the Mol ratio of water to carbon dioxide,the concentration of carbonate solution,the content of oxygen,the content of sulfur,the content of chlorine ion and medium velocity of flow etc.The anticorrosion measures to be taken during the normal production and shut-down period in the urea plant are put forward.For the normal production,some measures as follows must be strictly controlled:medium temperature,the content of oxygen adding to the system,the content of sulfur,the content of chlorine ion,the ratio of ammonia to carbon dioxide,the ratio of water to carbon dioxide.During the urea plant shut-down period,measures must be taken to control as follows:the ratio of ammonia to carbon dioxide and the ratio of water to carbon dioxide strictly,and fix the down time of enveloping the urea reactor according to the different situations.