Discussion on exhaust gas hydrogenation catalysts
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As we all know, exhaust gas hydrogenation catalysts need to be pre-sulfurized before their first use, in order to convert the oxidation state of the catalyst to a sulfided state. Do you know what the oxidation states of cobalt and molybdenum are? Also, why is it necessary to avoid exposing the catalyst to hydrogen at temperatures above 180 degrees before sulfurization?
Cobalt oxide, and molybdenum trioxide. Why come into contact with hydrogen? Why is the temperature increase during displacement in contact with hydrogen? Don’t understand
This is because after 180 degrees, hydrogen reduces cobalt oxide and molybdenum oxide, turning them into metallic elements and thereby removing their reactivity.
This post was last edited by adsl121 on 2009-5-6 00:15. CoO＋H2S « CoS＋H2O; DH0298=-13.4KJ/mol (1). MoO3＋2H2S＋H2 « MoS2＋3H2O; DH0298=-48.1KJ/mol (2). The second question is unclear
Agree with the view from the 3rd floor. However, my unit requires that the temperature not exceed 200 degrees during operation.
This post was last edited by adsl121 on 2009-5-6 00:17. Our pre-vulcanization doesn’t involve hydrogen; it only reacts with hydrogen sulfide
During pre-vulcanization, it should be avoided for hydrogen to come into contact with the catalyst at temperatures above 250 degrees in the absence of hydrogen sulfide. Please pay attention to each condition.
7# ltj: What does it mean by being careful about various conditions, as mentioned above? I wonder if one agrees with what was said on the third floor regarding hydrogen and the idea of offering it as an offering?
Is it because there’s a fear that it will react with oxygen to form water, thereby deactivating the catalyst?