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在尿素生产工艺流程中,用换热器进行热交换反应是必不可少的。其反应介质有氨、二氧化碳、水和氨基甲酸氨等,对尿素设备有很强的腐蚀性。特别是尿素生产中的二氧化碳汽提塔、高压冷凝器及高压洗涤器处于最苛刻的条件下,曾发生过严重的腐蚀事故。所以列管采用不锈钢制作。其余换热器因使用范围不同,内列管采用碳钢管—20~#钢。碳钢管不耐腐蚀,加之运行时间较长,生产中经常出现这样或那样的腐蚀问题造成泄漏。其方法是带压堵漏或临时停车堵管,或者是在大修时根据主管设备技术人员所掌握情况,设备容易腐蚀部位的列管进行估计性抽管更换。在更换过程中,
In the urea production process, using a heat exchanger for heat exchange reaction is essential. The reaction medium ammonia, carbon dioxide, water and ammonia carbamate, urea equipment is very corrosive. Especially in the production of urea in carbon dioxide stripper, high pressure condenser and high pressure washer in the most demanding conditions, there have been serious corrosion accidents. Therefore, the use of stainless steel tube production. The remaining heat exchanger due to the use of different ranges, the inner tube carbon steel pipe -20 ~ # steel. Carbon steel pipe is not resistant to corrosion, combined with longer running time, production often appear in this or that cause corrosion problems caused by leakage. The method is blocking with pressure or temporary parking blockage, or in the overhaul according to the competent equipment and technical personnel to grasp the situation, the equipment vulnerable to corrosion of the parts of the tube for the estimated replacement of pipe. In the replacement process,