In the urea production process using carbon dioxide stripping, how can the temperature differences at various points on the walls of the synthesis tower be better controlled?
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In the urea production process using carbon dioxide stripping, when heating the synthesis tower with air and steam, how can the heating time of the synthesis tower be reduced while keeping the heating rate under control and the temperature difference across various points on the tower wall within the required range (less than 30 degrees)? (In order to ensure that the temperature difference between various points on the wall of the synthesis tower does not exceed 30 degrees, it takes a long time for the temperature of the synthesis tower to rise to over 100 degrees, approximately 48 hours.)
Is there any better way to raise the temperature of the synthesis tower before starting the CO2 compressor?
Do you mean the temperature-raising passivation time by 48h?
On the condition that the temperature difference across various points on the tower wall remains below 30 degrees, it takes 48 hours to raise the temperature from room temperature to 100 degrees. If the temperature difference along the tower wall is not taken into account and the heating rate is kept below 12 degrees per hour, the time required will definitely be much shorter.
You just need to increase the air flow.
The temperature increase for passivation is usually 10 degrees per hour; a tower wall temperature of 125 degrees is sufficient. Together with 4 hours of maintaining that temperature, two shifts are generally enough. The key is to properly control the discharge of steam and water.
The heating rate is easy to control; the problem lies in the fact that when steam and air are used for heating, it’s difficult to raise the temperature in the middle part of the tower. This inevitably leads to a large temperature difference between the upper and lower parts of the tower as well as with the wall of the middle section, which affects the lining of the synthesis tower! What I would like to ask for help with is how to reduce the time required to heat up the synthesis tower, while ensuring that the temperature difference across various points on its walls remains below 30 degrees.
It is adjusted using the liquid and gas outlet valves of the synthesis tower. I’ve only been using it for 3 months as well
What are your high, medium, and low pressure steam pressures before heating the synthesis tower?
This post was last edited by 1025199692 on 2015-11-3 11:25. Before heating the synthesis tower, your high, medium, and low pressure steam pressures are 0, 0.1, and 0.05 MPA respectively
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