Questions about the fractionation tower
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In the diesel hydrogenation unit, the bottom of the distillation tower serves as a reboiler; diesel is obtained from the bottom of the tower, heavy naphtha is obtained from the top, and kerosene is produced via side streams. With the top temperature, bottom temperature, feed temperature, and side draw rate remaining unchanged, what changes occur in the range of kerosene and diesel when only the top pressure is increased? Shouldn’t the separation efficiency of the tower decline, with the kerosene boiling range widening, its initial boiling point dropping, and its final boiling point rising? Does the diesel cut-off temperature also decrease at the same time?
In other words, all fractions move downward; the initial boiling point of naphtha decreases as does its dry point, the initial boiling point of kerosene drops and so does its final boiling point. The initial boiling point of diesel also decreases, while that of 95-octane fuel remains unchanged
Under ideal conditions, the boiling range of kerosene and diesel will be on the lighter side; the boiling range of kerosene will not widen, while its initial and final boiling points will decrease. The initial boiling point of diesel will also decrease
The premise for all fractions to decrease is that the distillation column can still carry out effective separation, but what if the distillation column can no longer separate them? Is it the case that the initial boiling point of the kerosene component overlaps significantly with the dry point of naphtha, and at the same time, the dry point of kerosene overlaps significantly with the initial boiling point of diesel?
The premise for all fractions to decrease is that the distillation column can still carry out effective separation, but what if the distillation column can no longer separate them? Is it the case that the initial boiling point of the kerosene component overlaps significantly with the dry point of naphtha, and at the same time, the dry point of kerosene overlaps significantly with the initial boiling point of diesel?