【Q&A Question 033】2017.02.02
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This post was last edited by 955559 on 2017-7-21 21:43. [Q&A Question No. 033] Why does a hydrogenation catalyst need to be pre-wetted? 2017.02.02 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.) ) 1. Keep all catalyst particles in a wet state to prevent the existence of dry areas within the catalyst; the presence of such dry areas reduces the overall activity of the catalyst. 2. It causes the sulfides in sulfur-containing oils to be adsorbed on the catalyst, preventing difficulties arising from hydrogen reducing active metal oxides to sulfides, which helps to improve the activity of the sulfidation catalyst. 3. Pre-wetting can also prevent water from affecting the quality of the catalyst. 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 at 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 industry technical materials from the “Petrochemical Section”. http://bbs.hcbbs.com/thread-1654603-1-1.html Many prizes waiting to be won (Source: HaiChuan Chemical Forum)
During the pre-sulfurization of the catalyst, it is necessary to pre-wet it first; this is mainly to prevent the formation of dry areas, to reduce the activity after sulfurization, and to avoid the hydrogen reduction of the active metals in the catalyst.
1 Keep the catalyst particles uniformly wet to prevent the formation of dry areas in the catalyst bed, which could lead to incomplete sulfidation and thus reduce the overall activity of the catalyst； 2 It enables the sulfides in the sulfurized oil to adsorb onto the catalyst, preventing the active metal oxides in the catalyst from being reduced to metals, which helps to improve the catalyst’s activity ； 3 Avoid the impact of moisture on the catalyst.
1. Keep the catalyst particles in a wet state to prevent the existence of \"dry zones\" in the catalyst bed. The presence of a \"dry zone\" reduces the overall activity of the catalyst2; it causes the sulfides in sulfur-containing oils to adsorb onto the catalyst, preventing the active metal oxides from being reduced by hydrogen and thus facilitating sulfidation. It also helps to increase the activity of the sulfidation catalyst3. Pre-wetting can further prevent water from affecting the quality of the catalyst
The purpose of pre-wetting is to expose the catalyst to sulfur-containing oil before it comes into contact with hydrogen. One of its functions is to ensure that all catalyst particles are in a wet state, thereby preventing the formation of \"dry zones\" in the catalyst bed; the presence of such dry zones would reduce the overall activity of the catalyst； Another function is to cause the sulfides in sulfur-containing oils to adsorb on the catalyst, thereby preventing the active metal oxides from being reduced by hydrogen and making sulfidation more difficult; this is because the sulfidation rate of metal oxides is much faster than that of metals, which helps to improve the catalyst’s activity
Pre-wetting of the catalyst, through experimental research and industrial practice, has become a step in getting hydrogenation refining catalysts ready for use. This technique is particularly essential in sulfur-dropping bed hydrogenation reactions. It serves two main purposes: first, it ensures that all catalyst particles are in a wet state, preventing the formation of \"dry zones\" within the catalyst bed; the presence of such dry zones reduces the overall activity of the catalyst； Another function is to adsorb sulfides in sulfur-containing oils onto the catalyst, preventing the reduction of active metal oxides to sulfides by hydrogen and thus helping to improve the activity of the sulfiding catalyst. Additionally, pre-wetting can also prevent water from affecting the quality of the catalyst.
To prevent incomplete temperature distribution and to remove dust and impurities from the catalyst,
Because it has the following functions: 1. It keeps the catalyst particles in a wet state, preventing the formation of dry areas in the catalyst bed； 2. Adsorb sulfides in sulfur-containing oils onto the catalyst to prevent the active metal oxides from being reduced by hydrogen ； 3. Avoid the impact of water on the quality of the catalyst.
1 is to keep the catalyst particles in a wet state, thereby preventing the formation of dry zones in the catalyst bed. 2 is to enable the sulfides present in sulfur-containing oils to adsorb onto the catalyst, preventing the active metal oxides from being reduced to sulfides by hydrogen
Prevent the formation of a dry layer in the catalyst and enhance its activity
It facilitates the pre-sulfurization of the catalyst, enabling catalytic activity; it prevents areas of the catalyst from remaining unsulfurized, which helps in controlling temperature rise!