How do integrated and separate heating and separation systems for urea evaporation equipment operate in terms of product quality control?

The following suggestions are provided for reference. First, changing from an integrated design to a separate one yields better results, according to some SeaFriend users. Second, appropriately increase the height of the separator to enhance the separation effect.

It might be caused by an excessive load on the evaporation system; you can try enlarging the separator. Personal opinion.

In the CO2 stripping process, the evaporation equipment is all connected together; in some cases, the water and urine handling systems are separate. The size of the equipment is determined by the production capacity of the plant, and this was taken into account by the design team, who felt that there was no need to make any modifications to the equipment. The reasons for problems should be sought in terms of operation and management. The operating procedures have little to do with the structure of the equipment; it is essential to maintain proper control over the parameters of the evaporation process. Product quality is directly related to these parameters. For cleaning purposes, only two points need to be cleaned: the separated product and the throat section, once every two hours. During cleaning, cold water must be drained quickly and the valves must be opened and closed swiftly. The temperature setting for the second stage can be increased slightly, and then it should be restored to its normal value after cleaning. No other points need to be cleaned – there is no such requirement. The sight glass in the second stage should not be filled to capacity, and the liquid level at the inlet of the melt pump should be kept as low as possible (in plants where the liquid level is not controlled, the valve in front of the three-way valve should be left fully open). The temperatures in the first and second stages need to be adjusted carefully; they might be too high. It is necessary to refer to the temperature reading in front of the three-way valve used for granulation. Blockages can occur due to biuret formation, and in such cases, thermal treatment should be carried out.

I would like to ask whether the liquid level control valve for the second distillation stage is installed in front of the three-way valve in the granulation section, or at the outlet of the melting pump on the second floor?

In terms of design, it is generally installed in front of the tee valve in the granulation section. However, if this control valve is to be used, a level gauge must be installed in the secondary liquid phase; otherwise, remote control cannot be achieved.

Friend on floor 5, it’s great that you raised this question. My personal opinion is the same as that of the moderator on floor 6: this valve must be installed before the granulation tee valve, and it’s preferable that it be connected using flanges. Both valves should be located at the highest point in terms of elevation. The inlet/outlet pipes for the molten material should have a slope of at least 15 degrees. It would be inappropriate to install it in any other location; changes are recommended. The reason for this is that, during prolonged operation, if this level control valve fails, it will make it easier to drain the molten material from the pipes. If it isn’t installed at a high point, drainage could become difficult, leading to the risk of pipe blockages. This is just for reference.

Agree with the comment above. It is mainly to consider such extreme situations. But having a higher height also has its disadvantages; the melt pump is prone to malfunctioning due to liquid backflow.

“\"Those who cherish water are right,\" they said. On Monday this week, I saw the managers and staff from the design institute discussing this issue as well, and they said the same thing.