【Q&A Question 029】2017.01.29
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This post was last edited by 955559 on 2017-7-21 at 12:37. [Q&A Question No. 029] On 2017.01.29, why is a nitrogen atmosphere used instead of a hydrogen atmosphere during the catalyst drying process? The reference answers will be visible after responding; points are awarded by identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) During the catalyst drying process, if hydrogen is used for drying and the drying temperature exceeds 200 degrees Celsius, the active oxides on the catalyst will be reduced by hydrogen to form less valuable metal oxides. This creates difficulties in the subsequent presulfidization step, as the reduced metals are difficult to sulfide, thereby reducing the catalyst’s activity. New Normal Cup – Voting for the Top 10 Members of HaiChuan in 2016 is now underway; choose the member you care about the most (please cast your valuable vote for those in the Petrochemical Division). http://bbs.hcbbs.com/thread-1667649-1-1.html Summary post of Q&A questions for 2017 (updates available now). http://bbs.hcbbs.com/thread-1657793-1-1.html Summary post of daily questions for 2017 (updates available now). http://bbs.hcbbs.com/thread-1657794-1-1.html Summary post of Q&A questions from 2016 (all updates completed). http://bbs.hcbbs.com/thread-1597792-1-1.html Third round of selection for outstanding management members of HaiChuan. http://bbs.hcbbs.com/thread-1655902-1-1.html “Creative Ideas for Energy Saving” campaign in the Petrochemical Division. http://bbs.hcbbs.com/thread-1666758-1-1.html Xiaomi phones are up for grabs. Summary post collecting chemical engineering-related materials from the “Petrochemical Section”. http://bbs.hcbbs.com/thread-1654603-1-1.html Many prizes await you (Source: HaiChuan Chemical Forum)
Under certain pressures, the catalyst can be easily reduced to metallic elements or low-valent sulfides by high-temperature hydrogen, which affects the catalyst’s activity
During the catalyst drying process, if hydrogen is used as the drying medium and the drying temperature exceeds 200°C, the active oxides on the catalyst will be reduced by hydrogen to form less valuable metal oxides or metals. This creates difficulties in the subsequent presulfurization step, as the reduced metals are difficult to presulfurize, thereby reducing the catalyst’s activity.
During the catalyst drying process, if hydrogen is used as the drying medium and the drying temperature exceeds 200°C, the active oxides on the catalyst will be reduced by hydrogen to form less valuable metal oxides or metals. This creates difficulties in the subsequent presulfidization step, as the metals resulting from this reduction are difficult to sulfide, thereby reducing the catalyst’s activity.
Answer: If hydrogen is used as the drying medium and the drying temperature exceeds 200°C, the active oxides on the catalyst will be reduced by hydrogen to form less valuable metal oxides or metals. This creates difficulties in the subsequent presulfidization step, as the reduced metals are difficult to sulfide, thereby reducing the catalyst’s activity.
During the catalyst drying process, if hydrogen is used as the drying medium and the drying temperature exceeds 200 degrees, the active oxides on the catalyst will be reduced by hydrogen to form less valuable metal oxides or metals. This creates difficulties in the subsequent pre-sulfidization step, as the reduced metals are difficult to sulfide, thereby reducing the catalyst’s activity.
During the catalyst drying process, if hydrogen is used as the drying medium and the drying temperature exceeds 200°C, the active oxides on the catalyst will be reduced by hydrogen to form lower-valent metal oxides or metallic elements. This creates difficulties in the subsequent presulfurization step, as the reduced lower-valent metal oxides are difficult to presulfurize, thereby reducing the catalyst’s activity; metallic elements, on the other hand, become permanently inactive.
Hydrogen cannot be used during drying, as drying is a process of removing water. At that time, the catalyst was still in an oxidized state, so using hydrogen was dangerous; only after presulfurization did the catalyst become in a sulfided state
The hazards associated with hydrogen increase, leaks are difficult to handle, and it is necessary to prevent the catalyst from being excessively reduced and losing its activity!