Sulfur regeneration system
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The flow rate of acidic gas is 750 Nm3/h. The temperature at the top of the regenerator is 103°C, while the pressure at that point is 89 Kpa. The circulation rate is 86 t/h, and the amount of steam used is 12 t/h (steam at 0.35 Mpa is used as the heat source). The reflux rate is 16 t/h, which is above the normal range. The liquid level in the reflux tank is 41.9%. The temperature of the reboiler is 114.6°C, while the temperature at the bottom of the tower is 111.8°C (the acceptable range is 110–120°C; the steam ratio is around 0.14, and it’s difficult to increase the temperature at the bottom of the tower even by using more steam). The temperature of the amine solution after cooling is 31.9°C. I would like to ask everyone why the reflux rate in this unit is so abnormal, and why the temperature at the bottom of the tower is so low
This translates to a steam consumption of 140 kg per ton of amine solution. In terms of energy consumption, this figure is also roughly the same. How is the regeneration effect?
Take samples to analyze the hydrogen sulfide content in the amine-poor solution as well as the concentrations of solvent components such as MDEA. A hydrogen sulfide content of around 1.5–2 g/L is considered normal; a lower level is unnecessary as it also results in waste of steam. The low bottom temperature of the regeneration tower may be due to low concentrations of solvent components such as MDEA in the lean amine solution, along with a high water content.
When the hydrogen sulfide content in the lean liquid exceeds 1.0 g/L, the sulfur content in the desulfurization gas (catalytically liquefied gas) from the upstream unit becomes excessive; therefore, my unit must keep the hydrogen sulfide content in the lean liquid below 1.0 g/L.
Perhaps the sulfur content requirements for liquefied gas after desulfurization in your facility are relatively high; previously, the standard requirement was H2S ≤ 10 ppm. This is related to the uses of liquefied gas after desulfurization; it is understandable to set higher requirements for its use as a raw material in petrochemical plants, as it is also beneficial for the downstream liquefied gas deep desulfurization units.