Reboiler cannot pass steam
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Dear masters, please help me analyze this problem. Our distillation tower has such a strange phenomenon. There is no abnormality in the reboiler steam inlet pipeline. The tower temperature is decreasing, the tower liquid level is increasing, and the steam flow rate is getting smaller and smaller. Even if the steam regulating valve is fully opened, there is still almost no flow. I really don’t understand because my younger brother is so talented and ignorant. Our reboilers are thermosyphonic. At first I thought it was poor circulation, and then I increased the tank liquid level to 80%, but it still didn't work. Later, I considered that it might be a steam condensation problem, and then fully opened the bypass of the return water regulating valve, but it still had no effect. (After fully opening the bypass valve, there will be a steam overflow phenomenon, but as soon as the bypass valve is closed, the steam flow will disappear immediately). Masters, please help me. My brother is really anxious
1. If there is no problem with the circulation, there must be a blockage in the steam return water. Try to go back to the water and go straight, don't be afraid of being out of breath.
The tower temperature is decreasing, the tower liquid level is increasing, and the steam flow rate is getting smaller and smaller. Even if the steam regulating valve is fully opened, there is still almost no flow. -----------This is a phenomenon that the reboiler is clogged. The heat exchange effect is not good. The steam trap is blocked by liquid. When the heat exchange effect of the reboiler is not good, the steam cannot be condensed into a liquid state and cannot be discharged. The pressure in the reboiler will rise, so the steam cannot be added. Open the bypass of the steam trap, and the steam volume will increase immediately. You can try it. Just clean the lower pipe when the machine is stopped.
Combining the two, first determine whether the reboiler is blocked, and you can directly drain the return water for inspection. If it is clogged, you can only stop the car and deal with it. If it is not clogged, just deal with the backwater.
I agree with the fourth floor's point of view. We should consider it from many aspects and combine the two.
There are problems with the main return water path, most of which are caused by the valve head of the self-adjusting valve or manual valve falling off.
Heat exchange tubes will not suddenly have problems. Eighty percent of the time it's a gas line failure. First, fully open the hydrophobic bypass to determine whether the air intake system and heat exchange tubes are smooth. If there is no problem with the above, it is a hydrophobic failure. Generally, drain valves are prone to clogging.
It should be that the drain loop is not smooth, causing condensate to accumulate in the reboiler. Use a drain bypass or pry open the flange to drain. I've often encountered this problem before.
Check whether there are fluctuations in the pressure of the fractionating tower and the feed, and whether the steam trap and the back path are smooth (including whether the pressure is too high), because if the back path pressure increases and the liquid water in the reboiler is not discharged smoothly, it will also cause the above phenomenon. If there is a problem (blockage) in the reboiler heat exchange tube bundle, it can only be operated smoothly first and then purged when shut down.
The trap does not work and the steam condensate cannot be discharged, causing the pressure in the reboiler to be high and steam cannot be added. Then the tower temperature decreases and the tower liquid rises. We have also encountered such a situation. We tried to take a look at the auxiliary line of the trap, but we must be careful not to let the steam escape from the auxiliary line of the trap. Installing a liquid level gauge on the shell side of the reboiler can facilitate observation, prevent liquid accumulation in the reboiler, and facilitate operation and control.
I think everyone is right, we should consider it from two aspects: lol
There is air leakage when the bypass is turned on, and there is no steam as soon as it is turned off. It seems that there is a problem with the drain pipe and needs to be checked for blockage.
I have encountered this situation before. There should be no problem with the reboiler. It should be that the water in the reboiler is full and steam cannot enter, so the steam flow is getting smaller and smaller, and finally there is no more. Open both the condensate regulating valve and the bypass to drain water.
Use bypass to control steam, and repair the steam trap or main line steam self-regulating valve when shutting down
Did the reboiler have vapor lock at that time? Because yours is a thermosiphon, it is prone to vapor lock. When the temperature is high, it becomes difficult to repel water and the amount of steam cannot be lifted.
If the steam condensate is not delivered smoothly or the pipeline is blocked, it is recommended to try on-site diversion and discharge of the steam condensate.
This phenomenon is generally caused by clogging of steam traps and pipelines. The steam return valve can be adjusted and cleaned during shutdown. In addition, attention should be paid to whether the pressure changes and temperature changes of the distillation tower are real.
Trap problem! If there is air leakage when the bypass is opened, it means that the reboiler is not blocked. Check the trap and it will probably be fine!
Trap problem! If there is air leakage when the bypass is opened, it means that the reboiler is not blocked. Check the trap and it will probably be fine!
It is recommended to do the following checks: 1. Open the condensate drain to see if the heat exchanger is blocked. ； 2. Lower the liquid level, at least the gas phase return port of the material cannot be submerged.