Catalyst deactivation
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Does the QCS-04 catalyst from Qilu Petrochemical still need to be passivated after being taken out of the shift converter?
Cooling and nitrogen purging are sufficient; passivation is not required.
May I ask whether the owner will not use the removing agent, or will they reinstall it and continue to use it? If it is not to be used, lower it to room temperature and then discharge it; oxidation may still release heat, so watering it down can help cool it.
We are just replacing the catalyst on top of the converter
If it needs to be replaced, it must be cooled to room temperature, continuously purged with N2, and the catalyst at the top must be removed manually or using a vacuum pump. May I ask which manufacturer you represent?
To replace only the top portion, first cool it with nitrogen, and then a steam ejector can be used to remove the catalyst from the top.
For safety reasons, it is recommended that if the entire catalyst bed is to be removed, it should first be passivated and then cooled to room temperature before removal. Otherwise, during the removal process, cobalt sulfide and molybdenum sulfide can easily undergo oxidation reactions with the oxygen in the air, generating a large amount of heat that may lead to safety accidents.
In the case of a partial replacement, passivation is not necessary. However, the temperature inside the converter should be kept as low as possible; the safe temperature is below 30 degrees, and the lower the temperature, the better. Even in winter, in some areas in the north, if a emergency shutdown for replacement is required and the temperature inside the converter is at room temperature (around 0°C), it is not necessary to use nitrogen protection unless the catalyst needs to be removed. The oxidation process of the catalyst is very slow, so such oxidation has minimal impact on the catalyst.
Follow my advice: partially replace it with nitrogen and use protection； For a complete replacement, it’s necessary to carry out substitution and passivation – don’t listen to others trying to trick you!