Solvent concentration in the reflux tank at the top of the solvent regeneration tower
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The concentration of the lean liquid in our solvent regeneration unit is 27%, while the average concentration of the lean liquid in the tower top reflux tank is around 30%; at one point it even reached 50%. Dear colleagues, why does this situation occur? Can a reflux tank concentrate?
First, check to see if there are any errors in the analysis; normally, the liquid at the top of the tower is a vapor-phase condensate, and it should not contain much MDEA – the concentration is usually quite low.
I’ve measured it many times, and the concentration is always higher than that of the lean solution. What’s the reason?
Check whether the valve of the pipeline leading to the reflux tank is closed.
After the valve leading to the reflux tank is closed, how can a reflux cycle be established? Moreover, the fresh solvent supply port is generally located on the pipeline that leads the lean liquid into the absorption tower. So the possibility of fresh solvent mixing into the reflux tank, as you think, should be ruled out!
I’m not talking about the valve on the return line that leads to the tank; I’m checking to see if there are any other valves on the lines leading to the tank that aren’t closed properly. It’s also possible for other wires to come through.
The process for this tank is relatively simple; it can be understood as a liquid separation tank, with basically one feed line and two outlet lines. No solvent-related pipelines. (I even went ahead and checked the flowcharts for several sets of devices to confirm my claims.) ）
Is it going to stay like this? It was normal before, but now there’s an abnormality?
I’ve never done it before either; I only discovered it when I tried to do it some time ago. It doesn’t seem very scientific, so I came to Haichuan to ask everyone for their opinions.
Yes, when there is no suitable solvent available, it’s impossible for fresh solvent to enter; the process is very simple – it just involves a separation tank.
We keep the concentration of our lean liquid at 25%; a few years ago, the ammonia concentration in the reflux liquid was only 4%. Recently, the regeneration tower has been experiencing frequent flooding. After consulting the desulfurization agent manufacturer, they advised analyzing the amine concentration and oil content in the reflux liquid; the results showed an amine concentration of over 20% and an oil content of 200 ppm. It was recommended to increase the amount and frequency of transferring the reflux liquid to the acidic water stream, and so far this approach seems to be effective. The manufacturer believes that titration is used for the analytical testing, and what is measured is the content of inorganic ammonia, not organic ammonia. I’m also thinking about how to verify what the manufacturer says.