Main parameters for dry sulfiding of hydrocracking catalysts

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This post was last edited by jordan569 on 2010-10-21 at 23:33. Dry sulfiding in the catalyst reactor is usually carried out under the conditions of the plant’s operating pressure and with the circulation compressor operating at full capacity; the initial sulfiding temperature is 175°C, while the final sulfiding temperature is 370°C. During the process of dry sulfurization inside the reactor, it is first necessary to determine the maximum initial sulfur injection rate for catalyst sulfurization based on the flow rate of circulating hydrogen at the operating pressure. That is, at this maximum initial sulfur injection rate, the H2S concentration in the circulating hydrogen at the reactor inlet is estimated to be 0.30%–0.33% (by volume); this represents empirical data that can be used as a reference. Unocal’s empirical data suggests that the maximum initial sulfur injection rate for catalyst sulfurization can be estimated at 56 kg of CS2 per 1×104 Nm3 of circulating hydrogen. Table 1 shows the requirements for the heating rate and hydrogen sulfide concentration in the recycle hydrogen during catalyst sulfidation: Table 1 Requirements for temperature and hydrogen sulfide concentration during catalyst sulfidation. Heating rate during sulfidation stage (°C/h) and related technical requirements; Hydrogen sulfide content in recycle hydrogen (%V): 175–230°C: 3°C/h; the sulfidation temperature must not exceed 230°C before H2S penetration occurs at the outlet of the cracking reactor: 0.1–0.5%. At 230°C, the holding time must be ≥8 hours; heating is increased to 0.5–1.0°C once the dew point of the recycle hydrogen at the outlet of the cracking reactor is < –19°C. 230–290°C: 4°C/h; if the dew point of the recycle hydrogen at the outlet of the cracking reactor is > –18°C, heating is paused for 0.5–1.0 hours. 290–370°C: 6°C/h; again, if the dew point of the recycle hydrogen at the outlet of the cracking reactor is > –18°C, heating is paused for 1.0–2.0 hours. At 370°C, the holding time must be ≥8 hours; sulfidation is complete when the difference in dew points between the outlet of the refining reactor and the outlet of the cracking reactor is < 3°C, and the level of high-boiling fractions stops rising. 0.5~1.0