Why is sulfur removal carried out before increasing the operating rate in hydrogen production?
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Why is sulfur removal necessary before starting up the hydrogen production plant, and what are the requirements for carrying out this sulfur removal process? I hope experienced colleagues can share their insights.
You are probably referring to the conventional iron-chromium-based conversion process, during which sulfur release occurs; in the case of sulfur-resistant conversion processes, there is no such issue of sulfur release. Sulfur mainly remains as an impurity during the production process, primarily in the form of sulfates, and during the reduction of the catalyst, FeSO4 is reduced to H2S, which then escapes.
The raw material for medium-temperature catalysts is mainly FeSO4.H2O, and during the manufacturing process, a small amount or trace of FeSO4 gets enclosed within the precipitate particles. Additionally, the added chromium anhydride may also contain NaSO4 due to the production method. Significant sulfur release, as observable by conventional analytical methods, occurs only when the medium-temperature catalyst is reduced to a relatively high temperature.