Large fluctuations in liquid level in the hydrogen sulfide removal stripping tower
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Recently, due to the high processing volume and the addition of coker gasoline to the raw materials, the liquid level at the bottom of the hydrogen sulfide removal stripping tower has been fluctuating greatly. What is the reason for this? Is the processing volume too high, causing the stripping tower to be overloaded?
Is it related to the temperature control of the steam at the bottom of the stripper, or are there fluctuations in the properties of the feed?； If the processing volume is too large, the load on the top of the tower becomes high; if the water separation equipment such as the reflux tank is not large enough, it can also cause fluctuations in the liquid level at the bottom of the tower.
Is the bottom of the stripping tower a reboiler or a reboiling furnace? If it is a reboiler, it is related to unstable operation of the furnace!
The bottom of the stripping tower is a reboiler; the temperature in this boiler fluctuates little. The stripping steam is currently essentially shut off. Attempts were made in the past to turn off the steam, but that didn’t work either. The level control of the water separation vessel isn’t very precise either.
Reduce the flow rate by closing the valves that regulate the liquid level up and down, and try again; it’s likely related to the temperature of the medium inside the level gauge!
A large processing volume is one factor; another issue is that when the density of the raw material changes, the density parameter in the level gauge also needs to be adjusted, otherwise delays may occur and significant fluctuations in level control will result.
There are probably too many light components. . .
Is it steam stripping, or stripping with a reboiler or regenerator? The blending of gasoline increases the load on the vapor phase at the top of the tower; does the pressure at the top of your tower fluctuate significantly as well, with an upward trend? First, it’s necessary to check whether there is an issue with the stability of the heat source. If not, it can be assumed that the change in raw materials is the cause. In our hydrogen sulfide stripping tower, fluctuations occurred due to an increase in processing capacity; the solution adopted was to lower the temperature at the bottom of the tower and raise the pressure at the top, but this did not yield very good results in removing hydrogen sulfide. To meet the requirements of the increased processing capacity, adjustments were made.
The main issues are fluctuations in low temperatures and excessive variations in the properties of the raw materials; as long as the processing volume remains within the specified range, there is little impact.