Regarding the issue of introducing the new catalyst
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The carbon dioxide hydrogenation reactors are arranged in three beds in series, with coolers between each bed. During this overhaul, only the catalyst in the second bed was replaced; however, two temperature spikes occurred in the second reactor during operation. The first temperature spike happened right after pressurization, when the first bed had not yet started to react. This caused a one-day delay in driving; by the time of stamping, the temperature had already dropped to around 12 degrees. Does it seem like the activity of this catalyst is a bit too high? How can such accidents be prevented?
Reply to 1# GRC1980: It’s very likely that the activity is too high; deactivate Bed 2 using CO, or reduce the inlet temperature of Bed 2. I’m curious as to why only the second bed was replaced; usually, it should be the first bed that wears out first
It’s the former hydrogenation dicarbonyl reactor, right? For pressurizing the reactor, it is recommended to use an ethylene gas phase at 3.5 MPa. If ethylene cannot be used for pressurization, the method for the second floor is supported: use a CO cylinder to inject gas for passivation on the second bed.
Great question. Actually, we moved the catalyst from the second bed to the first bed; a new catalyst was installed in the second bed. It was to reduce the risk of excessive temperature during operation, but it still happened. Thank you for the suggestions from the two people above, but I would like to ask as well: when using CO for dulling, what amount should be injected? How can we ensure that a small amount of CO can pass evenly through the catalyst bed?
The specific amount of CO to be injected varies depending on the catalyst; you can consult the catalyst manufacturer for details.
The catalyst manufacturer needs to provide this quantity; are you using one from southern Germany? The G83C seems to be 1 cubic meter of catalyst per 1 Nm3 of carbon monoxide. It is necessary to consult the manufacturer for specifics. Especially since you place the fresh catalyst in the second bed, it may be necessary to cause a greater degree of passivation, or to lower the inlet temperature of the second bed. I’m thinking it might be better to place the new catalyst alongside the old catalysts in beds one, two, and three, and swap their order, hehe