High solvent loss during solvent regeneration
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Since the maintenance in May, our unit has experienced significant solvent loss; we basically have to add ethanolamine every day, and desalinated water must be added to the solvent storage tank every three days to maintain the system’s inventory level. The upstream desulfurization units were inspected, including dry gas desulfurization, recycled hydrogen desulfurization, and low-pressure gas desulfurization, as well as the sulfur flash tower itself. Each of these gas streams is equipped with a liquid separation tank after leaving the tower, and these tanks basically contain no substance. The cooling system and buried pipes were also checked, and no leaks were found. I don’t understand why our ethanolamine loss is so high I hope some experts can give me some advice.
What is the liquid level in the top reflux tank of the solvent regeneration tower, and can it be maintained? Perhaps the temperature is high after air cooling, and the venting of acidic gases from the tank top may carry some solvents along with it
The liquid level in the reflux tank has always been normal, and the reflux flow rate is also maintained around the design value. Our temperature after air cooling is indeed very high, deviating significantly from the design values. However, after water cooling, the temperature at the bottom of the acidic gas reflux tank remains between 40-60°C. Moreover, there has never been any issue with the liquid level in our regenerated acidic gas separation tank
Is the solvent filtration system being used too frequently? Or the valves that lead into the underground tank need to be kept very tight; otherwise, it will be serious! Generally, for a loss rate as high as yours, the cause is usually to be sought in equipment leaks; with such a high evaporation rate, it makes more sense that your steam consumption also increases accordingly, right?
For solvent regeneration, our steam usage ratio is as follows: approximately 120 T of ethanolamine is recycled, with around 19 T of steam being used. There is no liquid level at the exhaust port of the regeneration tower; we used a temporary modification line connected to the lean liquid pipeline at the bottom of the tower to compensate for the need related to the regeneration reboiler
Based on the data I’ve seen regarding solvent systems, it seems that this ratio for you is quite high…… Under normal circumstances, the ratio of steam to solvent flow rate should be maintained between 0.08 and 0.12; in your case, it’s almost 0.16! (Was it the same ratio for you in the last cycle?) It was brought up again in this cycle. ) It would be best if you sent me a screenshot of the DCS for your absorption-regeneration system; I’ll take a look at it for you.