a
Stripper top
∆P vapour
H
Stripper bottom
∆P
liquid
Vapour tra c (Actual volumetric ow)
Stripped product
Side stripper with reboiler
Side stripper with stripping steam
b
Stripper top
Figure 2 Typical side stripper hydraulics
yield and flash point are retained between the two strippers. A thermosyphon reboiler with 25 wt% vapour return condi- tion is assumed for the reboiled side stripper, while the other stripper uses superheated steam as stripping media. These figures show that much higher vapour traffic across the overhead vapour return segment is formed with the stripping steam stripper. The stripping steam stripper case also discloses that vapour and liquid traffic values are substantially reduced towards the bottom of the stripping steam stripper. Only stripping steam vapour and stripped liquid remain at the stripper bottom. Meanwhile, the strip - per with thermosyphon reboiler necessitates a higher liquid circulation amount. Since the reboiler vapour stream con- tains the heavy boiling range materials, the reboiler vapour flow rate is higher than the stripping steam flow rate. These unique differences in process conditions between the side stripper types should not be ignored for side strip- ping equipment sizing and operations. Otherwise, inferior side stripping performance can be experienced. Almost every side stripper relies on gravity hydraulics to receive the feed from the crude atmospheric column. Figure 2 illustrates a typical configuration between the crude atmospheric column and the side stripper. Liquid head (H) at the crude atmospheric column side draw should be high enough to overcome all pressure drop components across the liquid draw line, Δ P liquid , and stripped vapour return line Δ P vapour .² Otherwise, liquid draw rate reduction or starvation will be experienced.
Stripper bottom
Liquid tra c (Actual volumetric ow)
stripped vapour return line and the overhead condenser. The side stripper hydraulics and the overhead condenser capacity can be downgraded if equipment capacity and pipeline sizes are insufficient. On the other hand, the lack of a reboiler is one of the major advantages in this side stripper configuration. Less fouling tendency usually achieves better unit run length compared to reboiler side stripper operations. The most common stripping medium in petroleum refin - ing operations is steam. Superheated stripping steam is favoured to minimise the chances of equipment damage. The steams at saturates conditions can be condensed and increase the chance of equipment damage. Process conditions between these two types of side strip- pers are quite different. Typical vapour and liquid traffic patterns between the side strippers are compared in Figure 1a (top) and Figure 1b (bottom). Kerosene side stripping is selected as a process service. The same values of kerosene Figure 1a (top) and 1b (bottom) stripper vapour and liquid traffic comparison
Stripper comparison per operating mode
Operating parameter
Unit
Original Reboiler
Current Hybrid - ∆ 4% - ∆ 90%
Operating mode
-
Kerosene product draw
BPD
Base Base
Reboiler circulation rate (process side) *
Actual GPM lb steam /BBL
Kerosene side stripper unit stripping steam ratio
-
10.2
of kerosene product
Kerosene side stripper tray ∆ P
psi
Base Base Base Base
Base Base
Kerosene flash point
ºF
Stripped vapour return flow *
Actual ft 3 /min
+ ∆ 321% + ∆ 395%
Kerosene side stripper vapour return line ∆ P
psi
* Simulated value
Table 1
16
PTQ Q3 2025
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