【Sea River: Insights from Other Sources】Yan’an Petrochemical Plant upgrades a small-scale unit to a mixed dehydrogenation system for drying the reaction products, thereby extending its operational life” 　

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　Recently, Yan’an Petrochemical Plant overcame the technical challenges related to the drying system for the reaction products in its mixed dehydrogenation unit. By employing multi-faceted optimization strategies to improve the performance of the drying agents used for these reaction products, the plant was able to fully upgrade its core process systems, thereby ensuring the long-term stable operation of the facility. 　　As a key component in ensuring the stable operation of hybrid dehydrogenation units, the reaction product dryer plays a crucial role in removing hydrogen sulfide, aromatic solvents, and water from the reaction products. In 2024, the adsorption capacity of the desiccant used to remove reaction products declined on several occasions during the operation of this device, which caused the hydrogen sulfide level at the outlet to increase temporarily and affected the subsequent operation of the system. 　　To address this challenge, the technical team carried out systematic optimizations from multiple perspectives. In terms of technical parameters, the team made continuous adjustments to the boiling range of the aromatic solvents, keeping it within the range of 220°C to 385°C. During equipment operation, the team optimized and adjusted the timing of the regeneration sequence, reducing the time required for each regeneration by 10–12 hours and improving the adsorption efficiency of the desiccant used in the reaction products. In addition, the team paid special attention to the impact of post-cooling temperature on the performance of the desiccant. By upgrading the air cooling system, clearing the air cooling spray water pipes, and increasing the amount of spray water used for air cooling, it was possible to reduce the amount of aromatic solvents carried by the reaction products. The team also precisely controlled the amount of sulfur added to the reaction feed, thereby maintaining a stable level of hydrogen sulfide in the reaction products and ensuring optimal operation of the reaction product dryer. 　　Through a series of improvement measures, the operating conditions of the reaction product dryer were significantly enhanced; the hydrogen sulfide content at the outlet was reduced from 50 ppm to 3 ppm, and the operating cycle of the dryer was extended by more than half a year compared to before.