Discussion on the locations of the stabilizer top air cooler, aftercooler, and reflux drum (Advanced Technician topic)
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The last edit to this post was made by 328104062 on 2011-3-12 at 09:25. The process for stabilizing the reflux at the top of the tower is: tower –> air cooling –> aftercooler (water cooler) –> reflux tank. Why is the air cooling unit placed at the highest position (on the topmost platform)? (This is easy to understand; air cooling is more effective, and since it’s a cooler, it facilitates the natural flow of condensate.) Then why is the return tank placed on the middle platform? And is the aftercooler (water cooler) placed on the bottom layer? And it enters the reflux tank from the bottom, rather than from the top? One more thing: the tower top pressure is controlled by choke, heat path, and non-condensable gas zoning
It’s so that the water cooler can be filled with liquid, thereby improving the heat exchange efficiency
It is designed with safety in mind for easy operation.
Then why is it entered from below the reflux tank? It seems to be a question for testing senior technicians
Perhaps it is determined by the on-site conditions; our Luoyang branch’s design process follows the sequence of air cooling – water cooling – return tank, with the locations arranged from high to low, so there is no phenomenon as described by the poster
The water cooler is placed at the bottom; pressure is used to control the liquid level inside the heat exchanger, thereby adjusting the heat exchange area. This works on the principle of U-tubes, which is why feeding occurs from below.
In my understanding, the process used to overcome these bottlenecks involves utilizing the pressure difference between the top of the tower and the reflux tank, along with adjusting the opening degree of the control valves, in order to apply pressure. Regarding the choke point, it is located at the lower inlet of the reflux tank; the heat bypass is at the upper inlet. This arrangement is intended to maintain a favorable temperature gradient and density gradient, thereby facilitating the emergence of liquefied gas from the bottom of the reflux tank.
In my opinion, to facilitate the control of the pressure in the stabilizer tower, if the reflux tank is located below the cooler, fluctuations in the pressure of the reflux tank when non-condensable gases are discharged can easily affect the pressure in the stabilizer tower, as well as causing significant fluctuations in the flow rate of liquefied gas. The reflux tank is located above, which can increase the pressure drop for liquefied gas to be drawn into the reflux tank. It is beneficial for pressure control.
That’s because of your design; it’s not necessary to enter from the bottom. My setup allows entry from the top, and the cooler is also located on the platform above the reflux tank, which is on the ground. I haven’t found any issues with it, and it has been functioning normally all along.
If liquid gas enters the reflux tank from above, it is likely to vaporize easily, which is not conducive to operation.