HP March 2022 eBook—Energy Transition - 54

Process Optimization
Option 2: VR residue blending with
diesel. VR from the VDUs can be blended
with a low-sulfur stream to produce
ARD
unit
VR
ARDR
HCO
unit
2 in.
Unibon LSAR line
8 in.
FIG. 5. MAB units' blend.
TABLE 7. Results of the final blend
Parameter
Ash
Density at 15°C
Flash point, PMCC
S
H2
Pour point
Relative density at 60°F
Sulfur, total
Total sediment potential
Vanadium
Kinematic viscosity at 50°C
Aluminum and silicon
CCAI
TABLE 8. BFO results of Option 4
Parameters
Sulfur, % mass
Density at 15°C, kg/l
Flash point, °C
Kinematic viscosity at 50°C, cSt
Total sediment potential, % mass
H2S (liquid phase), ppm
Ash, % mass
Aluminum and silicon, mg/kg
Vanadium
CCAI
Modification I/P
UCO
UCO
BFO
unit
ULSD
Modification done
ULSD storage tanks
the required product (FIG. 4). To reduce
sulfur in VR bottoms, feed sulfur was kept
exceptionally low. This has resulted in
achieving sulfur in VR bottoms at 0.84%.
Adding 10-ppm sulfur gasoil, the resulting
sulfur was reduced to less than 0.5 wt% as
per VLSFO requirements. The results of
the final blend are detailed in TABLE 7.
The BFO viscosity quality is extremely
low at 45 cSt, compared to a maximum
of 380 cSt, and the CCAI is close to the
maximum limit.
Impact. It requires approximately
45% of 10-ppm gasoil as cutter stock.
This could lead to the possibility of final
blending aromaticity dropping below
40%, which, in turn, could lead to sludging.
Therefore, this option has an inherent
associated risk.
Option 3: Diesel as bunker fuel. Diesel
can be supplied as bunker fuel at prevailing
market prices. KNPC economics
will not be affected if the bunker price is
the same as the export gasoil price. In this
case, the bunker will be 10-ppm gasoil.
Units
% mass
kg/l
°C
mg/kg
°C
-
% mass
% mass
mg/kg
cSt
mg/kg
-
Result
0.02
0.9047
108
0.93
3
0.9052
0.48
0.04
7.2
45
5.7
793.1
Option 4: Using low-sulfur ARDR,
ULSD and UCO. The MAB refinery had
successfully completed its trial run for the
lab blend with ARD residue and a mix of
TGO and UCO to produce LSFO. However,
the blend viscosity was around 20
cSt-40 cSt. The blended batches were
stable and met specifications; therefore,
the MAB refinery commenced preparing
VLSFO batches. The desired results were
achieved after executing the modifications
shown in FIG. 5. The BFO results are
detailed in TABLE 8.
Option 5: VR and TGO. The MAA
refinery finally achieved the most economic
and feasible way of producing
VSLFO, using ARD distillate, VR and
TGO streams (FIG. 6). To achieve this,
the ARD unit was run with ARD resiMAB
VLSFO
0.39
0.894
110
37.2
0.1
0.2
0.06
4
5.7
785
MAA tank
0.5
0.896
> 110
40
0.06
0.2
0.02
4.6
6.7
785
VLSFO import: First cargo
0.46
0.937
104
345
NA
0.5
0.03
NA
NA
800
due product with a maximum amount
of sulfur at 0.35 wt%. The VR unit must
process low-sulfur ARD residue from the
ARD unit without mixing with high-sulfur
ARD residue from other MAA ARD
units. BFO results are detailed in TABLE 9.
TGO + ARD
distillate
VR unit
Bunker tanks
VR residue
FIG. 6. VR residue with TGO blend.
Hydrocarbon Processing | AUGUST 2021 | HydrocarbonProcessing.com
http://www.HydrocarbonProcessing.com
HP March 2022 eBook—Energy Transition

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