In the vapor pre-distillation tower, why isn’t light gasoline drawn directly from the outlet of the reflux pump? And to extract it separately from the upper part of the tower, does a water cooling system need to be installed?
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If extraction is done from the outlet of the return pump, there are air coolers and water coolers for the return flow; since the temperature is low, there is no need to install a separate light gasoline water cooler, and fluctuations should be smaller as well.
The pump operates unstably, and the vaporization of light gasoline is even more unstable; water cooling is employed to reduce the temperature and prevent vaporization.
You’re right; our device draws from the pump outlet, and the flow rate is very stable
I think the composition in the reflux drum at the top of the tower is different from that inside the tower; the composition in the reflux drum is relatively lighter
Our light gasoline is extracted from the 6th tray of the tower, as the composition of the material at each tray varies according to the distillation curve; the extraction point for light gasoline is determined based on the design parameters of the tower. Installing water cooling is likely intended for the safety of the tank area, to prevent the extraction temperature of light gasoline from becoming too high.
If the light gasoline is removed from the liquid phase in the middle of the tower plates, it is possible to reduce the amount of H2S dissolved in the light gasoline, thereby lowering its sulfur content and ensuring that the quality of the gas product meets the required standards. Light gasoline drawn from the reflux pump will result in a lighter composition of the gasoline, with an increase in the amount of light hydrocarbons present in it. Additionally, it is also possible to draw the light gasoline from the outlet of the reflux pump; however, this will lead to an increase in the amount of product at the top of the tower, which means that larger overhead coolers and other cooling devices, as well as a more powerful reflux pump, will be required