The problem of sulfurization in reforming catalysts
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I have just started learning about *reformation*. I heard that the reformation catalyst needs to be sulfided, meaning that the platinum in the catalyst reacts with hydrogen sulfide to form platinum sulfide. In the production process, will this platinum sulfide be reduced at some point? If so, then why is it considered an irreversible reaction? I would appreciate guidance from those who are experts. Thank you
This post was last edited by zhangyong6404 on 2009-8-20 at 11:38. Sulfur-containing compounds in the feedstock can produce hydrogen sulfide under reaction conditions; if this gas is not removed in a timely manner, it leads to a decrease in the dehydrogenation activity of the recycle hydrogen, thereby promoting the cracking of alkanes. Sulfur poisoning occurs mainly due to the adsorption of excess sulfur on the catalyst surface in reaction with metals. This reaction takes place in two steps, as shown by the following equations: Pt + H2S → PtS (irreversible) + H2; PtS + H2S → PtS (irreversible) + S (reversible) + H2. In the first reaction, platinum irreversibly adsorbs a portion of sulfur; this sulfur (referred to as irreversible sulfur) improves the performance of the catalyst by reducing the hydrodesorption of hydrocarbons, thereby contributing to an increase in the yield of liquid products. This step is generally completed by presulfurization. In the latter reaction mechanism, in addition to irreversibly adsorbing a portion of sulfur, platinum can also reversibly adsorb a portion of sulfur (reversible sulfur); this reversible sulfur can poison the catalyst and degrade its performance.
Thank you, moderator of floor 2; I understand now