Hydrocarbon Processing - October 2021 - 34

Plant Safety and Environment
Feed-LT distillate, and the second addition
is between the Feed-LT distillate and
Feed-HV distillate-1, as shown in FIG. 5.
The number of shells in the new heat exchanger
were changed to determine the
effects on energy savings and CO2
emissions
reduction rates. The rearrangement
of the existing Feed-VR heat exchangers
from four shells to three shells was studied,
and that one shell was used between
the Feed-PA and the Feed-LT distillate or
between the Feed-LT distillate and FeedHV
distillate-1 as alternative scenarios
for the new system.
Case 5. In this case, the target was
the rearrangement of the heat exchanger
hot side services for the Feed-HV distillate-2
from the HV distillate stream to
the VR stream, as well as the addition
of the modified heat exchanger between
the Feed-PA and Feed-LT distillate heat
exchangers, as shown in FIG. 6. All HV
TABLE 1. The effects of the pinch study on total fuel savings, simple payback periods
and IRR values at SOR
Alternative scenarios
Base Case [SOR]
-
New heat exchanger addition
3.98%
Shells in 1 x 1 (series*parallel)
New heat exchanger addition
5.91%
Shells in 2 x 1 (series*parallel)
New heat exchanger addition
7%
Case 1
Shells in 3 x 1 (series*parallel)
New heat exchanger addition
7.59%
Shells in 4 x 1 (series*parallel)
New heat exchanger addition
5.82%
Shells in 2 x 2 (series*parallel)
Modification of Feed-VR HEX
1.88%
Shells in 2 x 1 (series*parallel)
New heat exchanger addition
3.94%
Shells in 1 x 1 (series*parallel)
New heat exchanger addition
5.94%
Shells in 2 x 1 (series*parallel)
New heat exchanger addition
7.06%
Case 3
Shells in 3 x 1 (series*parallel)
New heat exchanger addition
7.66%
Shells in 4 x 1 (series*parallel)
New heat exchanger addition
6.25%
Shells in 2 x 2 (series*parallel)
Modification of Feed-VR HEX
2.44%
Shells in: 2x1 (series*parallel)
Modification of Feed-VR HEX +
New HEX addition
Shells in 1 x 1 (series*parallel) +
1 x 1 (series*parallel)
New heat exchanger addition
Case 4
Shells in 2 x 1 (series*parallel)
New heat exchanger addition
8.54%
Shells in 3 x 1 (series*parallel)
New heat exchanger addition
Shells in 4 x 1 (series*parallel)
34 OCTOBER 2021 | HydrocarbonProcessing.com
9.22%
5.1
6.29
19.01%
14.9%
4.46%
3.25
30.62%
2.59
38.55%
9.15
8.97%
7.59
11.74%
6.18
15.23%
4.9
19.88%
3.69
26.87%
3.36
29.63%
9.83
7.98%
7.66
11.59%
6.23
15.08%
4.92
19.78%
3.65
27.2%
Total duty
savings, %
-
Simple payback
period, yr
-
IRR, %
-
distillate streams were diverted to the
Feed-HV distillate-1 heat exchanger; in
this way, the Feed-HV distillate-2 heat exchanger
was revised as the Feed-VR heat
exchanger. The energy savings potential
of the rearranged pre-heat train was studied
to determine the effects on the fuel
consumption of the fired heater and CO2
emissions reduction rates.
Checking equipment adequacy. Energy
savings alternatives were analyzed
through validated unit simulation models.
In these analyses, the goal was to
identify possible equipment that could
create bottlenecks. The list of equipment
adequacy controls included:
* Heat exchangers-Design
temperature and design pressure
controls were performed
according to revamp operation
conditions; and ρV2
and vibration
controls were also considered
for all alternative scenarios.
* Pumps-Adequacy controls were
performed on the rated capacity
values in the datasheets of the
pumps, and it was determined
whether the pumps could meet the
corresponding differential pressure.
* Fired heaters-Fuel savings and
CO2
reduction rates were analyzed
for each case, and the effects of
the cooled down VR stream on
the lube oil plant unit fired heater
were analyzed to determine if
any bottleneck might occur.
Results. The VDU energy efficiency
performance,
data and CO2
fired heater
fuel
savings
emissions rates regarding
the pinch analysis were checked for each
alternative case. In the alternatives, SOR
and EOR operation parameters and results
were obtained from simulation models
and the economic feasibility and/or
CO2
emissions reduction rates were calculated
individually.
In Case 2 and Case 5, using the revised
5.77%
5.03
19.29%
Feed-HV distillate heat exchanger as the
Feed-VR heat exchanger proved an inadequate
solution due to the hot side design
pressure and hot side design temperature
limitations, respectively. Accordingly,
these two cases were eliminated from the
pinch study results.
The rates of increase on both VDU, lube
oil unit fired heater duties and fuel savings
were tabulated in TABLE 1 and TABLE 2 for
http://www.HydrocarbonProcessing.com
Hydrocarbon Processing - October 2021

Table of Contents for the Digital Edition of Hydrocarbon Processing - October 2021
