A problem with catalytic fractionation
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Why can increasing the absorption dose in the absorber reduce the reflux flow at the top of the fractionator, ensuring effective absorption and preventing oil carryover? I would appreciate some guidance from those who are more experienced.
Can the amount of absorbent in the absorption tower affect the reflux flow at the top of the distillation tower? I don’t think there’s a necessary connection here, but if the absorption dose is too high, it may cause an excessive load on the absorption tower, leading to over-absorption. This in turn can affect the operation of the stripping tower and even the stabilization tower, result in increased emissions of non-condensable gases, and a decrease in the yield of liquid hydrocarbons.
The oil absorption volume in the absorber should not affect the top of the distillation tower, but there is also a possibility of such an effect. The absorption efficiency is poor; gasoline is present in large amounts in the lean gas stream, and the rich reabsorption oil contains a high amount of gasoline, which returns to the distillation column and affects the load in the middle and upper sections as well as related operations. It is crucial to control the absorption effect; excessive absorption should be avoided, as it leads to poor desorption results. The presence of uncondensed gas in the stabilizer column increases pressure, and to ensure that the hydrogen sulfide content in the liquefied gas is within acceptable levels, thorough desorption is necessary. Excessive absorption is not energy-efficient, and it may also result in the entrainment of foam.
The idea that increasing the absorption dose in the absorber tower can reduce the reflux flow at the top of the distillation tower is correct. The temperature of the richly absorbed oil returning to the tower is higher than that of the trays at the return point (our 24th tray); it acts as a circulating flow between tray 21 (the outlet for light diesel) and tray 24, removing heat and thereby reducing the reflux flow at the top of the distillation tower. Increasing the absorption dose is equivalent to increasing the liquid-to-gas ratio, which inevitably improves the absorption efficiency; however, it is important to control the absorption dose
Increasing the absorption dose in the absorber tower can reduce the reflux flow at the top of the fractionation tower? I’ve never heard of that. All I know is that increasing the amount of absorbent in the absorber tower enhances its absorption capacity, allowing for more complete absorption of C3 and C4. However, excessive absorption can cause C1 and C2 to be absorbed as well, which increases the load on the bottom of the separation tower. Additionally, it can make it harder to remove non-condensable gases from the top of the stabilizer tower, reducing the yield of liquefied petroleum gas. Could it be that the absorption oil in the rich gas section of the reabsorption tower has increased accordingly, which in turn has increased the amount returning to the distillation tower, resulting in a decrease in the reflux flow at the top of the distillation tower?