Deethanizer problem
Thread Content
The liquid level in the reflux tank at the top of the deethanizer tower of the gas fractionation unit is often very low, which can easily cause damage to the reflux pump due to evacuation. So I would like everyone to discuss, because this tower is full reflux, can the pump be stopped directly without reflux when the liquid level is low? If possible, what impact will it have on operations?
This will definitely have an impact, because there is no material coming down, then the tray will dry out? You can directly open the inlet and outlet valves of the pump smaller, or set up a valve that can automatically adjust the valve opening according to the height of the liquid level.
Low liquid level in the reflux tank is caused by improper operation. First of all, do a good job of smooth operation. Control the reflux flow rate so that it is not too large. Control a certain amount of evaporation and pressure. Generally, the pressure is around 2.4Mpa and the reflux flow rate is 2-3 tons. It can be smaller depending on the situation. This is the premise of ensuring the C2 removal rate. There is no need for a large reflux flow rate.
No, if the reflux is stopped, the liquid level in the reflux tank at the top of the tower will rise and the tower pressure will become unstable, disrupting the normal operation of the tower. The liquid level in the reflux tank is low and the reflux can be appropriately reduced.
The reflux flow rate is determined based on the liquid level of the tank, so your reflux flow rate is determined based on the liquid level. You cannot increase the reflux flow without the liquid level. This is wrong. If you stop the reflux tower, the pressure will increase, which is overpressure, so it is recommended not to stop it. Second, the reflux flow rate can be adjusted according to the pressure and temperature. This is the right way to operate. For example, when the pressure is high, you can increase the reflux or reduce the low temperature and reflux volume. This is mainly based on the components of your raw materials. However, the operation of the deethanizer tower generally takes into account more conditions. You can explain what is causing the low liquid level in the reflux tank. This will make it easier to answer. My personal opinions are for reference only.
Failure to reflow coldly will cause instability in subsequent processing procedures and increase the amount of heavy components in propylene.
The operation of the deethanizer tower seems simple, but in fact, if it is not operated properly, it will lead to large fluctuations in the operation. My experience is the "lazy man's method" that is: Put the liquid level and flow rate of the reflux tank into automatic cascade (of course, the PID parameters must be set reasonably), change the heat source at the bottom of the tower to manual (generally no adjustment is made), put the pressure control into automatic, and do not adjust the water volume of the water cooler. This can ensure the smooth operation of the deethanizer tower.
It is absolutely impossible not to reflow. 1. Without reflux, the plate must be dry, and tower flushing may occur. 2. The quality of the product propylene and propane will not be greatly affected, but the yield will definitely be reduced. 3. Regardless of whether you discharge the non-condensable gas from the reflux tank at the top of the deethanizer tower to a low watt or a high watt, it may cause liquid in the gas pipe network. 4. You can ask the people upstairs to turn down the regulating valve to appropriately reduce the amount of backflow! !