Problems with the hydrogenation pre-distillation tower
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The light gasoline from the hydrogenation pre-distillation tower is withdrawn as a side stream, using natural pressure to drive the discharge; the top of the tower operates in full reflux mode. I would like to ask: is it possible for the light gasoline to be distilled at the top of the tower? Since light gasoline needs to be sent to the desulfurization unit, and the system pressure in that unit prevents light gasoline from being pumped there by its own pressure, it’s a real problem. Consider whether the cooling load of the tower top air cooler can meet the requirements I wonder if anyone has experienced this.
It first exchanges heat with the bottom oil from the pre-distillation tower in the shell side of the gasoline/heavy gasoline heat exchanger, and then enters the pre-distillation tower. The vapor at the top of the tower is cooled by an air cooler and a after-cooler before entering the reflux tank at the top of the pre-distillation tower; the reflux tank uses desulfurized fuel gas as its gas seal. The light gasoline from the reflux tank is pressurized by the reflux pump at the top of the pre-distillation tower; part of it is used as reflux at the top of the fractionation tower under cascade control of flow rate and tower top temperature, while another part is sent to the light gasoline extraction unit under control of flow rate and liquid level
In our plant, the gasoline hydrogenation unit is equipped with a pre-distillation tower; the heavy gasoline at the bottom of the tower is fed into the reactor for hydrogenation, while the light fractions are obtained from the top of the tower. The top of the tower features air cooling and water cooling, in addition to a heat bypass! The pressure is generally controlled at around 3 kilograms through the reflux tank pressure control valve! Then, part of it comes out from the reflux pump to be used for reflux, while the light fractions are sent out of the device! ! Fully feasible
Our OCT-MD FCC gasoline hydrogenation process is exactly as described above: it is fully feasible, easy to operate, and ensures that sufficient pressure is available to supply light gasoline to the desulfurization system.
It is completely possible; this issue has been proven through practical use in various organizations and multiple systems.