Precautions during sulfur recovery shutdown
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How should one proceed when the catalyst does not become deactivated during sulfur recovery shutdown? Please help me answer
Before use, catalysts are usually in an oxidized state or a partially presulfided state. The catalyst is only active in its sulfided state. Therefore, after the catalyst is loaded into the reactor, it must first be activated; typically, the sulfiding agent DMDS is added to introduce H2S into the gas phase. This H2S reacts with the metal oxides to form metal sulfides, and only under these conditions does the catalyst become active. Due to the high initial activity of the catalyst, it needs to be passivated (to reduce its initial activity), and low-nitrogen oils (straight-run diesel or kerosene) are commonly used for this purpose.
Strictly prevent oxygen from leaking in. Prevent catalyst combustion from damaging the catalyst
During the sulfur recovery shutdown, the catalyst does not become deactivated, but the elemental sulfur in the reactor must be purged. Our factory strictly controls the oxygen content in each combustion furnace.
If the hydrogenation catalyst is not deactivated, N2 can be introduced while the incinerator is still running in order to transfer part of the process gas from the hydrogenation reactor to the exhaust incinerator for combustion. The pressure inside the system is controlled using pressure control valves, and the amount of N2 is regulated so as to allow the system to cool down gradually.
Pay attention to the air supply volume; too high a level can cause ignition.