Decarburization of hydrogen production conversion catalysts

Carbon deposition treatment of conversion catalyst 1) Accident symptoms: ① Increase in the pressure difference at the inlet and outlet of the furnace tubes. ② The temperature at the upper part of the furnace tube rises, resulting in heat pipes and mottling. ③ The converted biogas has a high methane content. 2) Cause of the accident: ① Low water-to-carbon ratio. ② Catalyst poisoning. ③ The catalyst is unevenly packed or crushed. ④ The catalyst activity decreases. ⑤ The operating temperature and pressure experience large fluctuations. 3) Accident handling: (I)—Minor carbon buildup confirmed. —Reduce the load to 50%. —Increase the FV4302 setting to raise the water-to-carbon ratio. —It was operated for 5 hours under hydrogen supply to achieve carbon removal. (I)—Confirm severe carbon buildup. —Activate the small-cycle mode; the compressor operates in small cycles. — Turn off FV4303 to cut off the feed material. —Carbon is heated using steam, with the amount of steam being around 30–40% of that used in normal operation; the pressure is 1.0–1.5 MPa. The temperature must be strictly controlled so as not to exceed the level observed during normal operation. —The CO2 concentration in the exhaust gases is analyzed every half hour; carbon burning is terminated when it drops and stabilizes at a lower level. —If necessary, a small amount of air can be added to the steam for carbonization treatment, but the amount of air must be strictly controlled to prevent overheating. (The air-carbon burning process has a large thermal effect, leads to intense reactions, causes significant damage to the catalyst, and therefore should not be used.) — After carbon burning is complete, the feed gas is introduced again after re-reduction. If the catalyst cannot regain its normal activity after carbonization, the operation is stopped and the catalyst is replaced.