【Q&A Question 093】2016.07.22
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This post was last edited by liuquan1100 on 2016-7-22 20:14. [Q&A Question No. 093] 2016.07.22: What are the hazards of too low a reaction feed rate? The answer key will be available after responding; scoring is based on answering the key points. It can easily cause off-streaming and low space velocity, as well as excessive cracking and overheating.
The disadvantages of too low a feed rate are as follows: ① At the same temperature, a low space velocity results in a longer residence time, leading to intense hydrogenation reactions that make it difficult to control the bed temperature; ② A too low space velocity increases the likelihood of condensation reactions, causing coking on the catalyst surface; ③ A low space velocity leads to an excessive amount of light components in the products, especially an excess of gases； (4) Too low an air velocity can cause channeling in the reaction bed ； (5) When the feed rate is too low, the operation of the distillation system becomes more difficult.
Severe bed offset and channeling occur, leading to local hot spots and even excessive temperature rises.
At the same temperature, a low space velocity and long residence time lead to intense hydrogenation reactions, which can make it difficult to control the bed temperature and result in flow deviation.
The disadvantages of too low a feed rate are: ① At the same temperature, the space velocity is low and the residence time is long, resulting in intense hydrogenation reactions that make it difficult to control the bed temperature； ②Too low an air velocity increases the likelihood of condensation reactions, leading to coking on the catalyst surface ； ③Too low an air velocity results in a higher content of light components in the products, especially an increase in the amount of gas ； ④Too low an air velocity can cause channeling in the reaction bed ； ⑤When the feed rate is too low, it becomes more difficult to operate the distillation system.
High energy consumption, prone to flow deviation, uneven heating of the equipment, and so on
An excessive hydrogen-to-oil ratio increases the reaction depth, leading to more light components being produced through cracking, and as a result, the yield of the target product is low.
It is not conducive to the long-term operation of the equipment; it is harmful to the equipment! Additionally, it is harmful to the catalyst and does not contribute to its activity! The device has high energy consumption!
The feed pump is prone to damage, the heating furnace has too low a load, there is flow deviation in the reactor, and the catalyst is damaged
It is difficult to maintain temperature and pressure, and the product may react excessively to form other substances