Economics
The previously discussed pressure curve shows that
reducing the flash zone pressure from 50 mm Hg to 20 mm Hg can
reduce the resid production from 35% to 30% of the crude
charge rate. If the crude unit charge rate is 100 MBPSD, then
the resid rate would drop from 35,000 BPSD to 30,000 BPSD.
Depending upon the differential between HVGO and resid, the
economics table provides a simple calculation for the economic
value of the reduced resid. For example, if HVGO is worth
$1/bbl more than resid, the 5,000 BPSD of increased HVGO
production is worth $1.8 MM/yr. If the revamp costs for the
unit in question is less than this $1.8 MM, the project payout
is less than a year to reduce the flash zone pressure from 50
to 20 mm Hg. Other incentives can be calculated from the
presented material specific to each refiner’s crude slate and
operating pressure.
|
Incremental Profit per
Year |
|
for
Increased HVGO Recovery, $1,000/yr. |
| |
|
|
|
|
|
|
|
| |
Recovered HVGO, BPSD |
|
Upgrade
Incentive
$/bbl |
0 |
500 |
1,000 |
2,000 |
5,000 |
10,000 |
20,000 |
| |
|
|
|
|
|
|
|
|
0.0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
|
0.5 |
0 |
91 |
183 |
365 |
913 |
1,825 |
3,650 |
|
1.0 |
0 |
183 |
365 |
730 |
1,825 |
3,650 |
7,300 |
| |
|
|
|
|
|
|
|
|
1.5 |
0 |
274 |
548 |
1,095 |
2,738 |
5,475 |
10,950 |
|
2.0 |
0 |
365 |
730 |
1,460 |
3,650 |
7,300 |
14,600 |
|
2.5 |
0 |
456 |
913 |
1,825 |
4,563 |
9,125 |
18,250 |
In the non-optimized furnace
example previously discussed, the flash zone
temperature probably could be increased almost 50° F to experience a
similar coking tendency as the non-optimized design. The
previously discussed resid production chart indicates that increasing the flash zone
temperature from 700° F to 750° F reduces the Arab Heavy resid production from 32
to 27% of crude. Assuming a 100,000 BPSD crude rate, the resid
production will drop by 5,000 BPSD. The economics table
above shows that a 5,000 BPSD
reduction in resid production is worth $1.8 MM/yr. assuming a
$1/bbl differential between HVGO and resid. This incentive
could justify furnace and transfer line modifications allowing
better deep cut operation.
It should be noted that this furnace
temperature incentive ignores the increased cost for the
heater duty since much of the heat is recovered by the
exchanger train. A detailed engineering study should include
the heater duty cost. Similarly, the cost differentials
between HVGO and resid should consider that the heaviest HVGO
can contain higher concentrations of metals and asphaltenes
which may somewhat reduce incentives.
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