Regarding the issue of presulfurization
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What is the purpose of hydrogen pre-sulfurization? Why is water produced, and how is it produced?
The catalyst leaves the factory in an oxidized state and is inactive; it must be sulfided before it can be used. When hydrogen reacts with oxygen, water is definitely produced.
It means their reactions occurred, right?
Otherwise, why is water volume also considered one of the indicators that pre-vulcanization is complete?
H2S+MO--MS2+H2O
1. Both the fresh catalyst and the active metal components of the protective agents exist in oxidized states; these oxidized metal components have very low activity during the hydrogenation process, and only when they are converted to sulfided states do they exhibit higher activity. The purpose of catalyst sulfidation is to convert the active metal components of the catalyst from their oxidized state to their corresponding sulfided state, thereby enhancing the catalyst’s activity and stability. 2. Taking single-point sulfurization and liquid-phase sulfurization (with DMDS as the sulfurizing agent) as examples, the following reactions occur: C2H6S2 + 3H2 = 2H2S + 2C2H4MoO3; 2H2S + H2 = MoS2 + 3H2O; 3NiO + 2H2S + H2 = Ni3S2 + 3H2O; 9CoO + 8H2S + H2 = Co9S8 + 9H2O; WO3 + 2H2S + H2 = WS2 + 3H2O. It is necessary to calculate the cumulative amount of these waters in order to determine whether the catalyst has been fully sulfurized.
The purpose of presulfurization is to convert the oxidized catalyst into a sulfided state, endowing it with certain activity; the water produced is a byproduct of the reaction.
The catalysts produced by manufacturers are transported in their oxidized state; such oxidized catalysts are inactive, while those in the sulfided state are active. Sulfidation is a process that converts the catalyst from its oxidized state to its sulfided state through chemical reactions with hydrogen and hydrogen sulfide, and water is generated during this reaction.
Hehe, take a look at the explanation below.