【Q&A Question 076】March 17, 2018
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【Q&A Question 076】March 17, 2018: Briefly explain the disadvantages of too high or too low a distillation overhead temperature The top temperature is the main operating parameter for controlling the dry point of the oil at the tower top. If the top temperature of the tower is too low, it will not be possible to remove all the light components, resulting in an increased load within the tower and unstable operation ； However, an excessively high tower top temperature will result in the gasoline dry point not meeting the specifications. Therefore, excessively high tower top temperatures are inappropriate. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Due to the limitations on the number of posts in the “One Question per Day” section, “One Image per Day” has been moved to the registered devices section; you can access it through the directory I posted. For management purposes, if you need to access content from a few days ago, please go to the summary post below to enter the “My Registration Season” event – (Note: This event is currently underway in the Chemical Engineering section). https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=18978 For the daily questions section related to chemical engineering technology training in 2018: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888971 For the daily image section related to registered equipment in 2018: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888970 For the Q&A section related to hydrogen production and hydrogenation technologies in 2018: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888968 For the daily questions section related to LNG technology in 2018: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888973 For the Q&A section from 2017 (updates have started): https://bbs.hcbbs.com/thread-1657793-1-1.html For the daily questions section from 2017 (updates have started): https://bbs.hcbbs.com/thread-1657794-1-1.html For the daily image section from 2017: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1875160 For the list of daily questions related to LNG in 2017: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1804162 For the Q&A section from 2016 (updates are complete): https://bbs.hcbbs.com/thread-1597792-1-1.html
The top temperature is the main operating parameter for controlling the dry point of the oil at the tower top. If the top temperature of the tower is too low, it will not be possible to remove all the light components, resulting in an increased load within the tower and unstable operation ； However, an excessively high tower top temperature will result in the gasoline dry point not meeting the specifications. Therefore, excessively high tower top temperatures are inappropriate.
The top temperature is the main operating parameter for controlling the dry point of the oil at the tower top. If the top temperature of the tower is too low, it will not be possible to remove all the light components, resulting in an increased load within the tower and unstable operation; however, if the top temperature is too high, the dry point of the gasoline will not meet the required standards. Therefore, excessively high tower top temperatures are inappropriate.
Too high a pressure will cause backpressure in the reaction system, leading to vacuum in the compressor; too low a pressure will result in vacuum in the top reflux pump, causing interruption of the top reflux process and resulting in overheating at the top of the distillation tower, which affects product quality
1. An excessively high temperature at the top of the distillation tower causes the components of the distillate at the top to become heavier, reducing the tower’s separation efficiency and resulting in substandard distillation products. 2. An excessively high top temperature in the distillation tower increases energy consumption, while an excessively low temperature reduces the tower’s efficiency. 3. The excessively low temperature at the top of the fractionation tower causes some light components to remain at the bottom of the tower.
The top temperature is the main operating parameter for controlling the dry point of the oil at the tower top. If the top temperature of the tower is too low, it will not be possible to remove all the light components, resulting in an increased load within the tower and unstable operation ； However, an excessively high tower top temperature will result in the gasoline dry point not meeting the specifications. Therefore, excessively high tower top temperatures are inappropriate.
Last edited by Xin Zai Tian Bian on 2018-3-17 10:52. For the system: disruption of phase equilibrium and thermal equilibrium leads to increased energy consumption； For the product: if the top temperature is too high, the initial boiling point of the product at the bottom of the tower becomes too high, and the final boiling point of the product at the top of the tower becomes too high ； If the top temperature is too low, the initial boiling point of the product at the bottom of the tower becomes too low, and the final boiling point of the product at the top of the tower also becomes too low; all of this leads to substandard product quality.
The top temperature is the main operating parameter for controlling the dry point of the oil at the tower top. If the top temperature of the tower is too low, it will not be possible to remove all the light components, resulting in an increased load within the tower and unstable operation ； However, an excessively high tower top temperature will result in the gasoline dry point not meeting the specifications. Therefore, excessively high tower top temperatures are inappropriate
Either too high or too low a top temperature can result in the gasoline dry point not meeting the specifications; a high top temperature leads to severe water carryover in the reflux stream, an increase in tower pressure, and a higher risk of the reflux tank pump running out of liquid
An excessively high distillation top temperature can cause pressure buildup in the reactor, leading to vacuum formation in the compressor. Too low a level causes the top reflux pump to become empty, resulting in a disruption of the top reflux and leading to overheating at the top of the distillation column, which affects product quality.