Study On Corrosion And Protection Of High Or Medium Temperature Shift Furnace And Hydrogenation Reactor

Metal corrosion does harm for many fields of civil economy, including metallurgy, transportation, petroleum chemical engineering , aerospace, power source, communication etc. Corrosion and protection of materials are very important and elaborate work in chemistry industry because of the complicated working environment and strict production conditions. Ammonia synthesis is an important process in caprolactam production of Baling petrochemical company. In this paper, corrosion and protection measurements of several key devices in ammonia synthesis were discussed in detail. The results are as follows:1. The corrosion invalidation reasons of 104DA high temperature shift furnace were analyzed and discussed in detail. Macroscopical check, metallography analyses, magnetic power and ultrasonic wave detection, material components analyses and mechanical performance measurement were used to study the corrosion of 104DA device. The results show that the hydrogen corrosion cracking of 104DA device is caused by wrong selection of materials. Restoring and running administration methods were proposed according to the corrosion and running state of the device. After 4 years production running, abnormal running of super-temperature and super-pressure of the device didn't occur. It brings good social and economic benefit.2. The corrosion cracking reasons of the gland of R3002 caprolactam-cyclohexanone hydrogenation reactor were researched. The appearance, wall thickness, micro-hardness and mechanical performance of the corrosion sites were measured. And chemical elements analyses,metallogrsphy microscope,rupture scanning electron microscope were also used to study the corrosion of the device.The results indicate that the corrosion cracking is caused by the following reasons:Firstly,the mechanical performance of the device didn't meet the design demand because of the wrong selection of lower head material.Secondly,the phenomenon of super-temperature during the device running is the direct and main reason.In order to avoid the similar accident,effective inspection measures and corresponding running monitor methods of the device were proposed.3. Metallogrsphy analyses, magnetic power and ultrasonic wave detection methods were used to investigate the reason of hydrogen corrosion of R3004 medium temperature shift furnace.The results present that the hydrogen corrosion of R3004 is caused by the high running temperature, which is higher than the designed wall temperature.The corrosion of the devise is not serious at present.Through adopting strict safe running measures and corresponding process conditions the R3004 device can run a production period.