Study On Erosion Corrosion Of Multiphase Flow System Of Hydrogenation Air Cooler

Petrochemical industry mainly to produces all kinds of oil and gas products,which is the key of China’s economy.The normal operation of all kinds of air coolers applied in hydrogenation units is very important for safe production and continuous production of products.In many air coolers,because the fluid into the air cooler contains corrosive substances such as hydrogen sulfide,hydrogen chloride,ammonia,etc.,and the fluid itself has a fast flow rate and high temperature,there will be corrosion of high-pressure heat exchangers,air coolers and other tubes,resulting in leakage and even burst of air cooler tube tubes and affecting the normal production and operation.Based on hydrogenation air cooler of ammonium salt crystallization and erosion corrosion problems,research on the flow condition of different potential perforation failure cause and the leak location,through the simulation analysis,determine the cause of corrosion elements,offer the risk analysis of corrosion prediction,prevention and control of technical solution and optimization of process corrosion protection operation parameters such as recommendation for solution.The results are as follows: Fluid produces backflow inside the tube box to form a vortex,resulting in uneven distribution of air cooler fluid velocity and different flow direction.Through the distribution of the overall velocity and shear stress of each bundle,the results show that that the velocity and shear stress of the first tube,namely the 8th,9th,10 th,14th,15 th and 16 th root tubes,are larger and are most easy to erode and leak.Specific analysis of the eighth tube found that: The peak of the erosion rate and electrochemical rate of the four walls are concentrated at the entrance of the tube.The erosion corrosion and electrochemical corrosion promote each other and are more likely to cause leakage,especially on wall B.The analysis results of the parameter optimization and structural transformation are as follows: Based on the standard operational,the flow rate is decreased to 70%,increased to 120% and 150% respectively.By comparing the overall flow rate,shear stress,scouring rate and electrochemical corrosion rate,0.7-1 times flow rate is the most appropriate.Based on the standard working conditions,the heat transfer coefficient is increased to 120%,150%and reduced to 80% respectively to explore the optimal operation.By comparing the temperature distribution,shear stress distribution,erosion rate and electrochemical corrosion rate,1-1.2 times of heat transfer coefficient is appropriate.The fluid flow direction is changed by adding the partition at the tube box,and the distribution of diesel phase and the water phase is more uniform after adding the separator.When the partition is 60° from the bottom,the peak value of erosion rate is the lowest,and the peak value of electrochemical corrosion rate of each wall decreases.Therefore,the use of a separator with a bottom surface of 60° can effectively alleviate erosion corrosion.