【Daily Question No. 319】November 21, 2018
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【Daily Question No. 319】Why is it necessary to first reduce the temperature and then reduce the flow rate in the event of an accident in a hydrogenation unit on November 21, 2018? If the amount is reduced first, it will result in an increase in the heat supplied to the reactants, thereby increasing the degree of cracking and accelerating the hydrogenation reaction; this also increases the reaction heat, posing a risk of overheating the catalyst bed. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Correct: 3 wealth, Incorrect: 1 wealth ； Mass posting of posts – rated based on the lowest score ； Replies that are unrelated to the answer are considered spam and will be deleted immediately. For management purposes, if you need to view content from a few days ago, please go to https://bbs.hcbbs.com/home.php?mod=space&uid=3862647&do=thread&view=me&from=space through the summary post below
If the amount is reduced first, it will result in less being provided
Cooling down is the most convenient method for reducing blood pressure
Protect the catalyst, protect the reactor
A decrease in the feed rate to the reaction system leads to a reduction in space velocity, an increase in the temperature rise within the hydrogenation reactor, and an increased risk of reaction \"temperature runaway\".
Cooling first and then reducing the flow rate is intended to prevent excessive temperature rise in the reactor bed.
A sudden decrease in the amount of feedstock leads to a reduction in the density of the feed oil on the catalyst bed, or to an uneven distribution of it, which in turn causes sharp changes in the reaction heat or results in large temperature differences across the bed. This leads to intense secondary hydrogenation reactions and, as a consequence, a rise in temperature
The feed rate to the reaction system decreases, the space velocity drops, and the temperature rise in the hydrogenation reactor increases, making it prone to reaction \"temperature runaway\"
A decrease in the feed rate to the reaction system leads to a reduction in space velocity, an increase in the temperature rise within the hydrogenation reactor, and an increased risk of reaction \"temperature runaway\".
Temperature control is generally similar to that of a hot furnace; if the temperature is lowered first while the heating rate remains unchanged, this results in an increase in temperature. Furthermore, a decrease in the space velocity of the reaction can lead to excessive reactions within the reactor, causing the temperature to become uncontrollable.