Methods to reduce corrosion in the pre-hydrogenation system

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There are many ways to reduce corrosion, and the following are some common methods: (1) Use corrosion-resistant materials, such as stainless steel equipment or pipelines; (2) Apply anti-corrosion coatings or inject corrosion inhibitors; (3) Adjust the layout of pipelines to minimize impact corrosion; (4) Reduce the levels of acidic substances (H2S, HCl) in the feed and within the system, thereby reducing electrochemical corrosion of the equipment. Specific methods include: ① Injecting ammonia to neutralize acidic media (HCl)； ②Adsorbents (dechlorination agents) are used to remove acidic media (HCl). Comparing the various methods mentioned above, it can be seen that the use of stainless steel alloys enhances the corrosion resistance of the equipment; however, this increases the cost of the equipment. Whether it is cost-effective to use such alloys should be determined through careful consideration of the specific conditions of the installation. When using coatings, attention should be paid to the impact of high-speed fluids in the system on the coatings, whether the strength of the applied anti-corrosion layer meets the requirements, and whether the anti-corrosive material washed away affects the performance of the reforming catalyst; these issues require further analysis and investigation. Changing the flow direction of the pipeline can help to reduce impact corrosion to some extent, but it cannot mitigate electrochemical corrosion. Using ammonia water is a simple and feasible method, yet it is affected by factors such as the chlorine content in the raw materials, the amount of ammonia water used, and the operator’s level of responsibility; therefore, it is difficult to use this method to completely solve the problem of equipment corrosion. The adsorption effect of dechlorinating agents can also be utilized. It can effectively remove hydrogen chloride from the reaction effluent, with simple operation and is safe and reliable. The key issue is the need to find an efficient dechlorinating agent.