Hydrocarbon Processing - December 2020 - 44

Plant Design, Engineering and Construction
lower than in the previous cases due to
high CO2 content after the CO shift.
For the purpose of this study, it is as-

sumed that this fuel gas can be co-fired
and consumed with natural gas in the
duct burners of the SAGD equipment.

TABLE 3. Anticipated performance for revamp Option 2
Item

CO shift

PSA1

93,890

310,200

Feed capacity, sm /hr
Feed H2, mol%

45.6

52.3

Feed CO, mol%

51.6

32.6

Feed CO2, mol%

2.14

14.4

CO conversion, %

68.3

H2-rich product, sm /hr

132,985

110,800

H2 product purity, mol%

61.3

99.8

H2 recovery, %
3

Tail gas ﬂow/design, %

Tail gas pressure, kPag

265

TABLE 4. Anticipated performance for revamp Option 3
Item

CO shift

PSA1

Feed capacity, sm3/hr

168,277

238,338

Feed H2, mol%

45.6

61.3

Feed CO, mol%

51.6

7.28

Feed CO2, mol%

2.14

30.7

CO conversion, %

75.8

H2-rich product, sm3/hr

238,338

110,800

H2 recovery, %

H2 product purity, mol%

61.3

99.8

Tail gas ﬂow/design, %

51.1

Tail gas pressure, kPag

265
S92-cogeneration
S85-steam

S86-blowdown
S89-H2

Asphaltene

Sweet
syngas

Raw syngas
T

Asphaltene
gasiﬁcation

Acid gas
removal

S82

Partial
CO shift

T 100
S84

388-PSA

S83

S84-B

T
PSA 1

MIX-100
S90-tail gas

VLV-100

FIG. 6. Revamp Option 2: Partial CO shift with bypass.
S92-cogeneration
S85-steam
Asphaltene

Sweet
syngas

Raw syngas
T

Asphaltene
gasiﬁcation

Acid gas
removal

S82
T 100

FIG. 7. Revamp Option 3: Full CO shift.

S86-blowdown

DECEMBER 2020 | HydrocarbonProcessing.com

T
Full
CO shift

S88-PSA

S89-H2
T
PSA 1

This debottlenecking option is simpler and easier to control. It has the lowest HP syngas consumption, the highest H2 recoveries, a high amount of HP
syngas to cogeneration with a moderate
total installed cost for the CO shift unit,
and higher HP steam demand. The key
advantage of Option 3 is to resolve all
PSA1 operational issues for the switching valves and tail gas piping bottlenecks.
Option comparison and discussion.
Key performance parameters, syngas
fuel efficiencies and operating costs were
estimated for the three debottlenecking
options, using the rigorous simulation
models. The syngas fuel efficiencies are
based on the volume-based LHV from
the simulation. The operating costs/
revenues are estimated for comparative
purposes and are based on assuming local industrial unit pricing, the simulated
utility consumption (including electrical
power and HP steam), and the syngas/
tail gas supply. The estimated technical
data, as well as pros and cons, are summarized in TABLE 5. From TABLE 5, the
following observations can be made:
* Revamp Option 1 of adding a
new PSA2 train only reaches the
target H2 supply rates with medium
total installed cost, the highest HP
syngas usage, low H2 recoveries and
the lowest operating margin. Both
the PSA1 switching valve issue and
the tail gas hydraulic limitation still
exist. The HP syngas usage ratio
over total available syngas is 87%
over the 75% requirement for the
three gasifier trains in operation.
* Revamp Option 2 of adding partial
CO shift only meets the target
H2 production with lower total
installed cost, reduced HP syngas
usage and minor improvements
in PSA1 H2 recoveries and cycle
time. However, the PSA1 switching
valve problem still exists.
* Revamp Option 3 of adding
full CO shift not only meets the
target H2 production rates, but
also resolves the existing PSA1
operational problems with medium
total installed cost, lowest HP
syngas usage, highest H2 recoveries
and highest operating margins.

S90-tail gas

Recommendations. Revamp Option 3

(full CO shift) is recommended for the

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