Research For Safe Operation Of Hydrogen Manufacturing Converted Furnace Tube

Hydrogen conversion furnace is one of the most widely-used devices in modern petrochemical and oil refining enterprises.And the converter system is the core of the converter.As the hydrogen conversion furnaces are subjected to the action of hydrogen and high pressure and temperatureworking environment,which maylead to hydrogen conversion furnace tube to some damages including oxidation,corrosion,high temperature creep and so on.So it is of great significance to study the damage and failure of the furnace tubes and ensure the long period safe operation of the reforming furnace and the whole hydrogen production device.As HP40 Nb has good resistance to high temperature performance,carburizing,oxidation resistance and fatigue resistance,that widely used in the manufacture of hydrogen conversion furnace tube.Once a company used a 4-year hydrogen conversion furnace tube,which came to an explosion,causing the heating furnace broken down and the entire device pausing.However,the accident occurred when the furnace tube had only been put into use for 4 years,the working time of 1/3 service life.Therefore,this paper is aimed to analyze the details in this furnace tube.This paper introduces the ultrasonic testing technology used in the design of KSD4 furnace tube ultrasonic flaw detection equipment.The KSD4 furnace tube ultrasonic flaw detection equipment is used to detect the furnace tube,and the most serious attenuation area is found.The specimens near the attenuation region and the crack were selected and further experimental study was carried out.The experiment consisted of three groups of tube samples,group A was sampled the new furnace tube,group B was sampled in the worst case,and group C was sampled in the vicinity of the crack.The impact toughness experiments,tensile mechanics experiments and fracture scanning electron microscopy(TEM)of these furnace tubes were carried out respectively.The furnace tube was further analyzed by the above experimental results.The results show that the mechanical properties of the furnace tube are affected by the thermal shock of the furnace tube under the working environment of high temperature,high pressure and hydrogen.After the service,the plasticity of the furnace tube decreases and the impact toughness decreases,and the decrease of the performance of the furnace tube and the change of the microstructure of the furnace tube are consistent.This provides a good reference for the test of the deterioration of the furnace tubes and the calibration of the results of the HP40 Nb tubes using centrifugal casting.Through macroscopic observation,there are cracks in the tube while there are a lot of irregular small cracks,which are all from the inner surface of the furnace tube to the outside of the furnace tube.At the end of this paper,the energy view,fracture mechanics and finite element method are used to simulate and analyze the state of multiple cracks.By calculating the maximum stress and stress intensity factor values of the crack front,according to the finite element simulation results,it can be seen that when there are two cracks on the same straight line,it is more likely to expand than in the case of only one crack.In the presence of two parallel cracks,it is less likely to fail than in the case of only one crack.In this paper,we try to find the change of the micro-structure of the material when the macroscopic performance of the material decreases,which is of great significance for the future detection of the performance of the furnace tube by ultrasonic detection.The research on the safe operation of the furnace tube is of theoretical significance and practical value.