The hydrogenation unit is under construction. Don’t step on these 10 pitfalls!

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The 25th National "Safety Production Month" in 2026. Everyone pays attention to safety and everyone will investigate and rectify hidden risks in an emergency. -------------------------------------------------- "Starting a project is not a race, safety is the end point." ——Written to every chemical industry brother who is fighting on the front line of the hydrogenation unit. https://mmecoa.qpic.cn/mmecoa_png/LIjJWiag5KAByysTC7069o4OVrCbzPPBcwuxEicCvstibmqQV6subtwbRicF4XlNWwBZTv2eDCu1MRic6HiaDpYdKyQg/640?from=appmsg#imgIndex=1 01"Physical examination before starting work"”: Don’t let your equipment get sick. Imagine you want to run a marathon, but your shoes are worn out and the laces are loose - how can you still run? Before the hydrogenation unit is started, "small parts" such as valves, flanges, gaskets, and bolts are our "shoes and shoelaces." During the start-up process, the valves are opened and closed frequently, which makes employees prone to stress and fatigue, and loopholes in operation are prone to occur. Therefore, valve operation review and confirmation must be implemented - just like the pilot's checklist before taking off, not a single thing can be missed! 💡 Tips: The bolts that tighten the valve when it is cold are easy to loosen when it heats up. Just like a scarf tied tightly in winter, it needs to be loosened when it gets hot in spring - but the opposite is true here, it needs to be tightened again when it gets hot! 02 Heating and boosting: Slow work will lead to fine work, fast work will lead to accidents💡The heating should be like "stewing soup over low heat", not "stir-frying over high heat". Why should it be slow? Because the hydrogenation reactor is made of Cr-Mo steel (chromium-molybdenum steel), "temper embrittlement" will occur after long-term high temperature - just like bones become brittle when people are old, and they are prone to cracking due to rapid cooling and rapid heating. If the temperature rises too fast, the temperature difference between the inside and outside of the wall will be large, and the stress will be concentrated, which can range from flange leakage to equipment scrapping. 💡 Remember this number: Generally, the heating rate is controlled to be ≤30℃/h, and the cooling rate above 200℃ must also be ≤30℃/h. ⬆️ Boosting pressure requires “step by step” and the first start of construction: Before the wall temperature reaches 50°C, the pressure cannot exceed 1/4 of the design pressure. ； After exceeding 50℃, the pressure increase rate shall be less than or equal to 2.8MPa/h. Stop work and then start again.: Before the wall temperature reaches 93°C, it cannot exceed 1/4 of the design pressure. Just like inflating a bicycle, if the pump is pushed too fast, the inner tube will explode easily. Reactors are much more expensive than bicycles! 03Six Dangerous "Invisible Killers"”: Be wary of leaks during the start-up phase - as the Most Familiar Stranger equipment heats up, thermal expansion can cause small leaks in flanges and gaskets. Don’t panic if you find a leak. Use a steam hose to blow away the oil and gas (to prevent fire), and then check with soapy water or a flammable gas detector. The heating rate is controlled at ≤25℃/h (based on the furnace outlet temperature), which can minimize the harm of thermal expansion. Explosive mixture - air is the "accomplice". Never allow hydrocarbon raw materials to be introduced into the system before the air is removed! All equipment must be purged with inert gas or steam. remember: Hydrogen + air = explosive mixture, one spark and it's over. Water Dangers – The “Gentle” Killer Even a small amount of water in a hot oil system can cause big trouble. The reactor system needs to be dried with circulating hot gas, and the remaining water in the fractionation system is first flushed with cold oil, then hot oil, and finally discharged at the bottom and low point of the container. https://mmbiz.qpic.cn/sz_mmbiz_png/keqpjicn6JgIItCkxTwmPIA270gM5NPRE8ReZUdXnndR2aJuOpY2VBqjdMoDVTXDbKSxVJ7e2Q42mnlmqTWTo5Q/640?from=appmsg#imgIndex=2 ⚠️ Blood lessons : A certain factory once had water hammer in the equipment that was not drained away, causing water hammer during start-up, causing the pipeline to rupture! https://mmecoa.qpic.cn/mmecoa_png/LIjJWiag5KAByysTC7069o4OVrCbzPPBcwuxEicCvstibmqQV6subtwbRicF4XlNWwBZTv2eDCu1MRic6HiaDpYdKyQg/640?from=appmsg#imgIndex=3 Vacuum Collapse – Certain containers in the fresh feed surge tank and fractionation system were not designed for vacuum. When the equipment is cooling, the condensation of steam will create a vacuum. If the valve is closed, the container will be "deflated"! Therefore, it is never allowed to close the valve after using steam, and it must be filled with gas before cooling. High pour point raw materials - "solidification trap" During start-up, equipment that normally operates with lighter materials may enter high pour point raw material oil. Just like diesel oil solidifies in winter, high pour point raw materials will "freeze" at low temperatures. Therefore, steam tracing pipes should be used, and the operating temperature should be higher than normal when necessary. Tempering brittleness of the material - "Scars of Time" After the Cr-Mo steel reactor has been operated at high temperature for a long time, the material will become brittle. Fluctuations in temperature and pressure during the start-up and shutdown stages are most likely to cause "old injuries to relapse." 04 Alternate hot and cold: "Thermal expansion and contraction" philosophy of valve operation https://mmbiz.qpic.cn/sz_mmbiz_png/keqpjicn6JgIItCkxTwmPIA270gM5NPRE8ReZUdXnndR2aJuOpY2VBqjdMoDVTXDbKSxVJ7e2Q42mnlmqTWTo5Q/640?from=appmsg#imgIndex=4 When the cold exchange equipment is started, the cold flow should be introduced first, and then the hot flow should be introduced slowly. https://mmecoa.qpic.cn/mmecoa_png/LIjJWiag5KAByysTC7069o4OVrCbzPPBcwuxEicCvstibmqQV6subtwbRicF4XlNWwBZTv2eDCu1MRic6HiaDpYdKyQg/640?from=appmsg#imgIndex=5 Why? Leakage occurs because of uneven heating and cooling inside and outside the equipment. When the temperature rises to the specified temperature, the temperature rise must be stopped and constant temperature heat tightening must be performed - allowing the bolts and gaskets to "stretch" in place in a hot state to ensure no leakage during long-term operation. 💡 Operation instructions : Cold first and then hot, the word "slow" comes first ； The heat is tight and there is no need to worry about leakage. 05Nitrogen replacement: Before the start of the "lung clearing" exercise materials are introduced into the equipment, nitrogen replacement must be done, and the oxygen content in the equipment must be